Publ ished by The Internet-First Univers ity Press Founding of the Maize Genetics Cooperation News Letter at Cornell University Volumes I & II Rollins Adams Emerson (1873–1947) A 90th Anniversary Tribute Edited by Lee B. Kass Edward H. Coe, Jr. Michael N. Cook Margaret E. Smith Judy L. Singer This Book – https://hdl.handle.net/1813/66550 Books and Articles Collection – https://ecommons.cornell.edu/handle/1813/63 The Internet-First University Press Directory – https://ecommons.cornell.edu/handle/1813/64826 C ornel l Univers ity This content appears online at Cornell University’s eCommons for open access distribution and then in the more traditional physical form (bound book) for a modest user fee. This approach obviates the need for other libraries (or indeed individuals for personal usage) to acquire, catalog and store this content. However, redistribution and all other rights remain with the copyright holders. The IFUP was co-founded by J. Robert Cooke and Kenneth M. King. Online access to this digital book is at: https://hdl.handle.net/1813/66550 Books and Articles https://ecommons.cornell.edu/handle/1813/63 The Internet-First University Press Directory (All content through August 2019) https://ecommons.cornell.edu/handle/1813/64826.2 Perfect bound copies of this book may be ordered as separate Volumes (Volume I and Volume II) via e-mail: digital@cornell.edu Cover photo: Rollins Adams Emerson (1873–1947), Head of Cornell University Department of Plant Breeding from 1914–1942 (Courtesy of Plant Breeding files, Cornell University) Published by The Internet-First University Press Ithaca, NY, USA © 2019 Lee B. Kass, Edward H. Coe, Jr., Michael N. Cook, Margaret E. Smith, Judy L. Singer and Plant Breeding & Genetics Section, Cornell University All rights reserved, except as noted above. Founding of the Maize Genetics Cooperation News Letter at Cornell University A 90th Anniversary Tribute Volumes I & II i Thomas Hunt Morgan and Rollins Adams Emerson Willard Straight Hall, Cornell University, Ithaca, New York. Headquarters of the 1932 Sixth International Congress of Genetics, 24-31 August 1932. Morgan was President of the Congress and Emerson the General Chairman of the Local Committee. (Courtesy of Edward S. Buckler) ii Founding of the Maize Genetics Cooperation News Letter at Cornell University A 90th Anniversary Tribute Volumes I & II Edited by Lee B. Kassa, b Edward H. Coe, Jr.c Michael N. Cookd Margaret E. Smitha Judy L. Singera aPlant Breeding & Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853 bDivision of Plant and Soil Science, West Virginia University, Morgantown, WV 26506 cUnited States Department of Agriculture-Agricultural Research Service, Plant Genetics Research Unit and University of Missouri, Columbia, Missouri 65211 dCollection Development & Digital Collections, Albert R. Mann Library, Cornell University, Ithaca, NY 14853 PLANT BREEDING & GENETICS SECTION CORNELL UNIVERSITY Ithaca, New York The Internet-First University Press https://ecommons.cornell.edu/handle/1813/62 iii Copyright © 2019 by Lee B. Kass, Edward H. Coe, Jr., Michael N. Cook, Margaret E. Smith, Judy L. Singer and Plant Breeding & Genetics Section, Cornell University, Ithaca, New York All rights reserved. The online version of this book may be downloaded for personal use only. Mass reproduction and any further distribution requires written permission of the copyright holder. Published by The Internet-First University Press Ithaca, New York Co-founders: J. Robert Cooke and Kenneth M. King Front Cover: Rollins Adams Emerson (1873-1947), Head of Cornell University Department of Plant Breeding from 1914–1942 (Courtesy of Plant Breeding files, Cornell University) Inside Back Cover: 1945 Synapsis Club group photo (Reprinted from Murphy & Kass 2011, p. 157; Courtesy of Plant Breeding & Ge- netics and the publisher) Back Cover: Maize Genetics Cooperation News Letter Volumes, compiled by R.A. Emerson (Photo image by Judy Singer) Scanned by Jeffrey Piestrak, Collection Development & Digital Collections, Albert R. Mann Library, Cornell University Proofread by Judy L. Singer Reviewed by Mark E. Sorrells Produced by J. Robert Cooke iv To the Legacy of R.A. Emerson & To Maize Cooperators Worldwide v vi Volume I CONTENTS Frontispiece T.H. Morgan and R.A. Emerson at 1932 International Congress of Genetics . . . . . . . . . . . ii Copyright . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Dedication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v Foreword by Edward S. Buckler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ix Preface and Acknowledgments by Lee B. Kass and Edward H. Coe Jr. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xi Group Photograph of Congress Attendees, 1932 International Congress of Genetics . . . . . . . . . . . . . . . xiii Introduction by Editors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Introduction to Maize Genetics Cooperation News Letter, Volume 1 (1929) . . . . . . . . . . . . . . . . . . . . . 7 Reprint: Maize Genetics Cooperation News Letter Volume 1 (1929) . . . . . . . . . . . . . . . . . . . . . . . . . 8 Introduction to Maize Genetics Cooperation News Letters Volumes 2-14 (1932-1940) . . . . . . . . . . 41 Reprint: Maize Genetics Cooperation News Letter Volume 2 (1932) . . . . . . . . . . . . . . . . . . . . . . . . 42 Reprint: Maize Genetics Cooperation News Letter Volume 3 (1933) . . . . . . . . . . . . . . . . . . . . . . . . 46 Reprint: Maize Genetics Cooperation News Letter Volume 4 (1933) . . . . . . . . . . . . . . . . . . . . . . . . 64 Reprint: Maize Genetics Cooperation News Letter Volume 5 (1934) . . . . . . . . . . . . . . . . . . . . . . . . 74 Reprint: Maize Genetics Cooperation News Letter Volume 6 (1934) . . . . . . . . . . . . . . . . . . . . . . . . 87 Reprint: Maize Genetics Cooperation News Letter Volume 7 (1934) . . . . . . . . . . . . . . . . . . . . . . . . 92 Reprint: Maize Genetics Cooperation News Letter Volume 8 (1934) . . . . . . . . . . . . . . . . . . . . . . . 104 Reprint: Maize Genetics Cooperation News Letter Volume 9 (1935) . . . . . . . . . . . . . . . . . . . . . . . 123 Reprint: Maize Genetics Cooperation News Letter Volume 10 (1936) . . . . . . . . . . . . . . . . . . . . . . 150 Reprint: Maize Genetics Cooperation News Letter Volume 11 (1937) . . . . . . . . . . . . . . . . . . . . . . 173 Reprint: Maize Genetics Cooperation News Letter Volume 12 (1938) . . . . . . . . . . . . . . . . . . . . . . 201 Reprint: Maize Genetics Cooperation News Letter Volume 13 (1939) . . . . . . . . . . . . . . . . . . . . . . 245 Reprint: Maize Genetics Cooperation News Letter Volume 14 (1940) . . . . . . . . . . . . . . . . . . . . . . 269 Volume II Introduction to Maize Genetics Cooperation News Letters Volumes 15-21 (1941-1947) . . . . . . . . 331 Reprint: Maize Genetics Cooperation News Letter Volume 15 (1941) . . . . . . . . . . . . . . . . . . . . . . 332 Reprint: Maize Genetics Cooperation News Letter Volume 16 (1942) . . . . . . . . . . . . . . . . . . . . . . 390 Reprint: Maize Genetics Cooperation News Letter Volume 17 (1943) . . . . . . . . . . . . . . . . . . . . . . 452 Reprint: Maize Genetics Cooperation News Letter Volume 18 (1944) . . . . . . . . . . . . . . . . . . . . . . 507 Reprint: Maize Genetics Cooperation News Letter Volume 19 (1945) . . . . . . . . . . . . . . . . . . . . . . 541 Reprint: Maize Genetics Cooperation News Letter Volume 20 (1946) . . . . . . . . . . . . . . . . . . . . . . 592 Reprint: Maize Genetics Cooperation News Letter Volume 21 (1947) . . . . . . . . . . . . . . . . . . . . . . 628 Annotated Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B.1 To scroll to a menu item, click on it. To return, use the “previous view” command. vii APPENDICES Appendix I. Introduction to reprint of Kass, Lee B., Chris Bonneuil and Ed Coe. 2005. Cornfests, cornfabs and cooperation: The origins and beginnings of the Maize Genetics Cooperation News Letter. Genetics 169 (April 1): 1787-1797; online May 6, 2005: http://www.genetics.org/content/169/4/1787.full.pdf+html . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A.1 Reprint: Kass et al. 2005 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A.2 Appendix II. Introduction to reprint of Coe, E.H. and L.B. Kass. 2005. Maize Genetics Cooperation News Letter files: Expanded chronological list of materials and related cooperation. Maize Genet- ics Cooperation Newsletter 79 (Oct. 31): 72-76; available online April 2005: http://mnl.maizegdb.org/mnl/79/06CoeKass.htm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A.13 Reprint: Coe & Kass 2005 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A.14 Appendix III. Contributor’s Biographical Sketches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A.19 To scroll to a menu item, click on it. To return, use the “previous view” command. viii FOREWORD CELEBRATING 90 YEARS OF MAIZE COOPERATION By Dr. Edward S. Buckler Research Geneticist, U.S. Department of Agriculture - Agricultural Research Service, Robert Holley Center, Cornell University; and Adjunct Professor of Plant Breeding & Genetics, School of Integrative Plant Science, Cornell University When Dr. Kass asked me to write a foreword for this volume, I was surprised; surely there were others in the maize community better suited? However, I can trace my scientific lineage as a maize geneticist directly to the community built by the Maize Genetics Cooperation News Letter (MNL). I did my PhD at the University of Mis- souri in evolution and archaeology. However, while I was there, Drs. Ed Coe (editor of MNL from 1974-2000, after Emerson, and others) and Jim Birchler (MNL co-editor with Mary Polacco, now Schaeffer) introduced me to maize genetics. In 1993, I drove in a van to my first Maize Meeting with their graduate students. Every year since, I have attended the Maize Genetics meeting, where over 600 people of all ages come to discuss and work on the intricacies of maize. But, before jet setting around the US or planet was possible, and before the myriad of Internet communication’s tools were available, the Maize News Letter was a visionary way to build an effective and collaborative community. How did this community come about? As I look out the window of my office today, I see the building where, in 1932, the greatest geneticists from around the world gathered at Cornell University for The Sixth International Congress of Genetics. Despite the world being in the throes of the Great Depression, scientists traveled to Ithaca, New York to discuss the incredible breakthroughs occurring in genetics — the first Golden Age of genetics. At the time, the rediscovery of genetics was about 30 years old and if we look at the meeting attendees and talks, we can see the origins of many of the major branches of genetics represented for the first time. And, at that meeting, Dr. Rollins Emerson (1st MNL Editor) called together a side group of maize geneticists to develop a process to share knowledge and discovery across the community. This side meeting invigorated the previously established Maize Genetics Cooperation News Letter, which would, for the next decades, be the key catalyst for the community. What other newsletter is a cooperation newsletter? This sense of cooperation was instrumental to the creation of our community, initially with sharing of information and genetics stocks. But over time, these founding geneti- cists and breeders collaborated with nearly every other field of science – physiology to archaeology to engineering. Cooperation evolved and added collaboration. Today, the breadth of science that is possible when working on maize through collaboration is what I love most about our science. Our community answers questions as precise as how a change in a single base of DNA affects the structure of the tassel to questions as overarching as how maize can play a sustainable role in feeding the world in the face of climate change. The newsletter let people know years before an official publication came out what various groups were working on. While there is always some compe- tition for discovery, the community around the newsletter was dominated by cooperation and collaboration. In this volume, Drs. Kass, Coe, and co-editors show how the Maize News Letter is central to the origins of maize genetics and community, and in no small part the origins of the entire modern genetics community. While I nev- er had the honor of meeting Rollins Emerson, Barbara McClintock, George Beadle, or Marcus Rhoades, I have worked on questions that all of these people asked and even reanalyzed some of their data that was first reported in the MNL. In this volume, Lee Kass brings to life these founders of our scientific community, where we came from, and how our community was built. While this work highlights some scientific questions that remain open, the greatest lesson the MNL can teach us and future generations is how to build a community of learning and discovery, where the scientist, the science, and society all win. ix x PREFACE Rollins A. Emerson, second Head of Cornell’s Department of Plant Breeding, established the Maize Genetics Cooperation and the Maize Genetics Cooperation News Letter (MNL) at Cornell University (Kass et al. 2005, reprinted in this volume). It was published at Cornell from 1929 through 1955, and continued publication at The University of Illinois, Indiana University and The University of Missouri (Coe & Kass 2005, MNL 79; reprinted in this volume). This 90th Anniversary book was inspired when in April of 2018 Kass searched the MaizeGDB online database (https://www.maizegdb.org/mnl) to locate a complete reference, including page numbers and author affiliations, for an article published in MNL 17, 1943.  Coe, former MNL editor (1975-2000), helped locate the reference and confirmed that it was not possible to gain knowledge of affiliations for historical purposes without examining hard copies of the MNL. Many of those early News Letters had been retyped for the digital venue, and contributors’ reports were not always shown in groups by affiliation (e.g., University, College, or other Institution), as can be found in the originals. While searching for this reference, it occurred to Kass that Plant Breeding & Genetics at Cornell had Emerson’s bound volumes of the earliest MNLs that were not in the Cornell Library. Before sending these MNL bound volumes (Vols. 2-14, 1932-1940; Vols. 15-21, 1941-1947, compiled by Emerson for the College of Agriculture Library) to the Cornell Archives, we desired to scan them “verbatim” and make them available in digital format.  We also have a copy of what is now considered MNL Volume 1, 1929, Emerson, pp. 1-30. This was located among the papers of E.G. Anderson, at The University of Missouri, by Coe (MNL 53, Foreword, 1979). It was reprinted in a hard copy of MNL 53:117-130, March 1, 1979, “IV. 50 Years Ago,” as part of the Historical Notes of the MNL, but was not initially available in digital format (see MNL archived volumes https://www.maizegdb.org/mnl; https://mnl. maizegdb.org/mnl/53/). A pdf version of MNL Volume 53 has since been added as a link: (https://mnl.maizegdb. org/mnl/53/00MNL%2053or.pdf). Volume 22 to date has been added as verbatim pdf versions by Coe and are posted at the online database, (https://www.maizegdb.org/mnl). The early MNL articles were presented online, but were incomplete (available at Maize Newsletter Archives, https://www.maizegdb.org/mnl). Also, the early volumes (1-3) were mis-numbered on this website [the correct volume numbers were published by Coe and Kass (2005)]. The 1932 issue was listed as Volume 1, but the first Volume issued in 1929 was not included at this archive link (this volume was reprinted in MNL 53, as mentioned above). Considered to be the first MNL by Emerson, Volume 1, 1929 is correctly cited as MNL 1 at MaizeGDB, Reference Record, Emerson, R.A., 1929, MNL 1:1-30, “You who attended the “cornfab” in my hotel room ...” (https://maizegdb.org/data_center/reference?id=9020573). This web-link also reports that MNL 1 was reprinted in MNL 53. Biographical references for R.A. Emerson are included at: (https://maizegdb.org/person?id=12877). Because the early MNLs were not available in digital format, we reached out to Robert Cooke, publisher of the Internet-First University Press, to ask if he might have an interest in publishing, as an e-book, Volumes 1-21 (1929-1947) of the Maize Genetics Cooperation News Letter, including the correspondence that accompanies these volumes. He was enthusiastic to publish the volumes if we could make arrangements to have them scanned. We were fortunate that Michael Cook of Albert R. Mann Library Digital Collections had the funding and resources for this endeavor, and he offered, in addition, to produce a Cornell eCommons webpage where the scans could also be viewed (see Introduction). Cook also suggested reprinting Coe & Kass (2005) in this volume for ease of comparison with original MNL volume numbers (see Appendix II). We are, therefore, pleased to present here the early MNLs compiled by R.A. Emerson, with relevant photographs (see Introduction) and perspectives on its founding at Cornell University, 90 years ago this April. Lee B. Kass Edward H. Coe, Jr. 9 February 2019 xi ACKNOWLEDGMENTS We acknowledge with thanks: the staff of Albert R. Mann Library for providing resources for scanning Maize News Letters; Jeffrey Piestrak, Digital Collections Specialist, for making the excellent scans; and Michael Cook, Head of Collections, for supervision. We also acknowledge Ed Buckler, Cornell University, for providing 1932 ICG photos; and Evan Earle, Director Cornell Archives and Peter Fraissinet, L.H. Bailey Hortorium, for identifying the building where the 1929 group photo was taken. Dr. Alexandra S. Kadner, WV medical writer and scientific consultant, provided assistance by alerting us to more recent cooperative-type Newsletters. We thank The Genetics Society of America for granting permission to reprint Kass et al. 2005, Genetics 169 (April 1): 1787-1797. We deeply appreciate Mark Sorrells, Professor of Plant Breeding & Genetics, for reviewing the manuscript. Hard copies of this volume were made available courtesy of School of Integrative Plant Science, Plant Breeding & Genetics Section. LBK thanks Plant Breeding & Genetics, Cornell University, and Plant & Soil Sciences, West Virginia University for logistical support. Special recognition is given to our publisher, J. Robert Cooke, for encouraging our efforts to make this project a reality. xii xiii Group photo of Sixth International Congress of Genetics, 24-31 August 1932, Ithaca, New York, taken outside northwest corner of the New York State Armory and Drill Hall (now Barton Hall), Cornell University Campus. (Courtesy of Edward S. Buckler) [For IDs see Jones (1932, Volume 1) or Crow (1992)] xiv [Left Half] Group photo of Sixth International Congress of Genetics, 24-31 August 1932, Ithaca, New York, taken outside northwest corner of the New York State Armory and Drill Hall (now Barton Hall), Cornell University Campus. (Courtesy of Edward S. Buckler) [For IDs see Jones (1932, Volume 1) or Crow (1992)] xv [Right Half] Group photo of Sixth International Congress of Genetics, 24-31 August 1932, Ithaca, New York, taken outside northwest corner of the New York State Armory and Drill Hall (now Barton Hall), Cornell University Campus. (Courtesy of Edward S. Buckler) [For IDs see Jones (1932, Volume 1) or Crow (1992)] xvi INTRODUCTION The Maize Genetics Cooperation News Letter (MNL) was founded by Rollins Adams Emerson (1873-1947) at Cor- nell University and has been published annually since 1929. It is a compendium of notes and information about on-going research intended to be shared throughout the maize research community. The News Letters were pub- lished by the Department of Plant Breeding at Cornell University until 1955. A partial name contraction to News- letter was made with Volume 64 in 1990. The publication became fully and only digital with Volume 88. Emerson was head of Cornell’s Department of Plant Breeding from 1914 to 1942 (Murphy & Kass 2007, 2011). He had been called from the University of Nebraska to succeed H.J. Webber, who established the Department at Cornell in 1907. Emerson and his students established a school of Maize Genetics and Cytogenetics, and in 1929 he founded the Maize Genetics Cooperation News Letter. In this book we offer a full page verbatim scan of the first MNL, sent to maize cooperators by R.A. Emerson on 12 April 1929. The scan was made by Coe from the archived files of E.G. Anderson, who had spent his retirement years at the University of Missouri. Anderson had received his Ph.D. (1920) at Cornell with Emerson (Murphy & Kass 2007, 2011, pp. 24, 31, 33-34, 119). As Emerson planned his retirement, he arranged to have all copies of the MNL bound for the College of Agricul- ture Library. Two bound volumes resulted (see back cover). When the new library (Albert R. Mann Library) was established, Emerson’s bound volumes remained in the Department of Plant Breeding and eventually were passed along to Margaret Smith (see Kass et al. 2005). The back cover of this volume shows the two bound volumes of the early MNLs that were compiled for the library. Verbatim scans of these first bound volumes are also included here, and the originals will be deposited in the Cornell Archives for their History of Science Collections. The first set of bound MNLs, which we located in the Department of Plant Breeding at Cornell (MNL, Vols. 2–14, 1932–1940), was numbered by hand in pencil, beginning with October 1932, labeled “Vol. 2.” (MNL 2; Coe & Kass 2005). The “Historical Notes on Maize Cooperation” listed on p. 56 of MNL 14 (1940) states that the mim- eographed letter of April 12, 1929 is “considered News Letter 1.” The Cornell Plant Breeding Department’s bound volumes appear to have been numbered retroactively under the guidance of Emerson, who was the secretary for MNL, Vol. 14, 1940. The binding on the first set of bound News Letters clearly shows that 1932 was considered to be MNL Vol. 2 (see image on back cover). The MNL included unpublished data, unselfishly contributed by geneticists from many institutions (Murphy & Kass 2011, p. 23). This first and unique cooperative effort was so successful that it became widely copied. For example, the first volume of the Drosophila Information Service [DIS], issued in March 1934, mentioned the Em- erson Cooperation and that Drosophila workers had planned to establish a similar service to that of the maize workers (Bridges & Demerec 1934, p. 2). Similar publications soon followed: Mouse Genetics News (Snell 1941, Law 1948), reestablished as Mouse News Letter (Dunn 1949); Neurospora Newsletter (1962-1985), later named Fungal Genetics Newsletter (1986-2007), and currently named Fungal Genetics Reports (2008-current); Arabidopsis Information Service (Röbbelen 1964-1973, Kranz 1974-1990), later The Arabidopsis Information Resource (TAIR); Zebrafish Science Monitor (1991-2000), which became ZFIN NEWS and then The Zebrafish Information Network (2004-current); Worm Breeders Gazette (WBG) (Edgar 1975-current); and a variety of other plant Newsletters that have come and gone, such as Gramene and The Rice Genetics Newsletter (1984-2007). See others as listed on the Gramene website (http://archive.gramene.org/newsletters/newsletters.html). The first MNL (Vol. 1, 1929) was sent “To Students of Maize Genetics” in April of 1929, shortly after Emerson’s “cornfab,” held in his hotel room at the AAAS Christmas meetings, December of 1928, in New York City (Kass et al. 2005). This mimeographed letter included a long folder of linkage information—linkage data, lists of genes, and “rainbow maps”—and the names of researchers assigned to nine of the ten linkage groups known at that time (see MNL 1, 1929, p. 2). Most of the researchers assigned to study the maize linkage groups were working at Cornell; the more familiar names were [George W.] Beadle, [Barbara] McClintock, [Allan C.] Fraser and of course R.A. 1 Emerson. Others working on linkage groups were affiliated with Bucknell University, Lewisburg, Pennsylvania; Iowa State University, Ames, Iowa; The University of Minnesota, St. Paul, Minnesota; Ohio Agricultural Exper- iment Station, Wooster, Ohio, in cooperation with the Office of Cereal and Crops Diseases, Bureau of Plant In- dustry, U. S. Dept. of Agriculture, Beltsville, Maryland; University of Wisconsin, Madison, Wisconsin; and Kansas State University, Manhattan, Kansas. Barbara McClintock shared the study of linkage group B-LG with Lewis J. Stadler of The University of Missouri, Columbia, Missouri. Beadle would later share the 1958 Nobel Prize in Physiology or Medicine for “… discovery that genes act by reg- ulating definite chemical events” (https://www.nobelprize.org/prizes/medicine/1958/beadle/facts/). McClintock, 1983 Nobel Laureate in Physiology or Medicine, was awarded an unshared prize for her “discovery of mobile ge- netic elements” (https://www.nobelprize.org/prizes/medicine/1983/mcclintock/facts/; Kass 2013ff.). Ever honest and forthcoming, Emerson claimed “no credit” for assembling this first summary of data. Professor Fraser had “abstracted the available published papers” before leaving for a year in Europe, Emerson explained. Emerson also noted that his graduate student, “Mr. Beadle, has completed that work and assembled my own un- published records and has arranged all the tables and charts” (Emerson, MNL 1, p. 1). Supplementary communications were sent out by Beadle in November and December of 1929 and February of 1930. Emerson sent a 17-page mimeographed folder of revised maps on April 17, 1930, and in July 1930 he sent a second folder of linkage data that included 23 pages. The latter two communications were found in the papers of E.G. Anderson and at the Rockefeller Archives Center, respectively. They were identified by Emerson in his His- torical Notes published in MNL 14:56, but were not included in the Plant Breeding Departments’ bound volumes. These communications (not included here) were reprinted in MNL 54 (1980) and MNL 72 (1998), and are listed in Coe & Kass (2005). The Maize Genetics Cooperation was formalized during the 1932 Sixth International Congress of Genetics held at Ithaca, NY (MNL 2, 1932), and was mentioned in Emerson’s Historical Notes published in 1940 (MNL 14:56). Shortly before that conference, Emerson notified maize geneticists of his plan to establish a Cooperation of Maize Geneticists (ref. MNL 14:56; Coe & Kass 2005). Soon after the Congress, Emerson and his former student Marcus Rhoades issued what has been considered to be the first “Maize Genetics Cooperation News Letter” (October, 1932), in which unpublished data were freely shared among the members. Rhoades assumed editorship of the MNL after Emerson and George Beadle. Rhoades numbered the October 5th 1932 MNL as number 1, but as we have shown this had been identified by Emerson as MNL 2, 1932 (see scanned MNL Vol. 2 in this volume, and bound volume image on back cover; see also Kass et al. 2005, reprinted Appendix I; Coe & Kass 2005, reprinted Appendix II). A group photograph taken at the 1932 Congress of Genetics is published in this Anniversary volume (before the Introduction). The photograph is slightly different from the one published in the Proceedings (Jones 1932, Vol. 1), given that Emerson’s dog is included in the lower right corner. The scan was made from a photograph that was saved from the trash by Edward (Ed) Buckler, when he was affiliated with North Carolina State University (NCSU). We also have a similar photo in the Plant Breeding and Genetics files at Cornell. By examining the list of attendees at the Ithaca Congress (Jones 1932, Vol. 1, p. 25), we concluded that the framed photo that Buckler had saved from a storage closet at NCSU had been obtained by C.H. Bostian, who had joined the faculty at North Carolina State College, Raleigh, North Carolina (now NCSU) in 1930, and retired in 1973 (Bostian Wikipedia). He is identified by number 368, in the upper left side of the 1932 Ithaca Congress group photograph (see Crow 1992 or Jones 1932, Vol. 1). In addition, the President of the Ithaca Congress, T.H. Morgan, and R.A. Emerson, the General Chairman of the Local Committee, are seen in a photo (frontispiece) taken in Willard Straight Hall, the Headquarters of the Congress (Morgan 1932). This scanned image was also made from a photograph saved by Buckler. An image of the Executive Committee for the Congress, also from this NCSU collection, can be viewed on the eCommons webpage (Maize Genetics Cooperation News Letter, eCommons https://ecommons.cornell.edu/handle/1813/58745). 2 At the 1932 International Genetics Congress, Emerson gave an opening address titled “The Present Status of Maize Genetics” (Kass & Bonneuil 2004). In his introduction he declared: “I cannot refrain from noting here a very real advantage experienced by students of maize genetics ... I am aware of no other group of investigators who have so freely shared with each other not only their materials but even their unpub- lished data. The present status of maize genetics, whatever of noteworthy significance it presents, is largely to be credited to this somewhat unique, unselfishly cooperative spirit of the considerable group of students of maize genetics. In this connection I want gratefully to acknowledge the help of many persons who have contributed directly or indirectly to this summary statement of the status of maize genetics” (Kass 2001, Kass et al. 2005). By October 1932, MNL 2 (= Rhoades MNL 1) was issued from Cornell, and provides a record that ten linkage groups had been assigned to ten maize workers. A report of the meeting held at the International Congress of Genetics was included in this MNL, as recorded by Secretary Rhoades (see also Kass et al. 2005). Emerson’s num- bered MNL 3, January 23, 1933, 16 pages (= Rhoades MNL 2), is identified as the “Third Corn News Letter” (MNL 14:56), and provided a long list of known genes of maize, among other items. By November 13, 1933, Rhoades issued a two-page call for information anticipating the forthcoming MNL 4, published the following month. This November call is not included in the Emerson bound volume, but was included in the files at Missouri (Coe & Kass 2005). By December 1933, Emerson’s and Rhoades’ MNLs were both numbered in agreement as MNL 4, 7 pages. Thereafter, the MNL volume numbers correspond (Coe & Kass 2005). Rhoades left Cornell in 1935 and Emerson assumed editorship once again. In 1937, Derald Langham, Emerson’s graduate student (Ph.D. 1939), became editor through MNL Volume 13 (March 1939). Emerson re-assumed edi- torship through 1944 (MNL 18), with the exception of MNL 15 (April 1, 1941), edited by Professor Fraser. Fraser had planned to assume editorship but, sadly, died in September of 1941. Robert L. Cushing was hired in 1943 to replace Fraser. Cushing edited MNLs 19 and 20 (1945-1946) and was succeeded by Harold H. Smith as editor and Professor of Genetics through MNL 26 (1952). It may have been Smith, in consultation with Emerson, who had the second set of MNLs (Volumes 15-21) bound for the library. We have also included scans of the Cornell Plant Breeding Department’s second bound volume of Maize News Let- ters (MNL 15-21, 1941-1947; see image on back cover). We believe that Emerson may have compiled this bound volume prior to his death on 8 December 1947. Note that MNL Volume 21, which we include in this book, was not scanned from this second bound volume. Due to technical difficulties with the library’s book scanner, MNL Volume 21 was scanned from an unbound identical Albert R. Mann Library copy instead. As mentioned in the Preface, Cook provided funds to scan these early maize volumes, and provided guidance on copyright, and other items of value to include for historical perspective. Professor Margaret Smith (Cornell Ph.D. 1982) has held Cornell’s bound MNL collection for many years (Kass et al. 2005). She joined the Plant Breeding faculty in 1987. R.P. Murphy (Murph), former Chair of Plant Breeding (1953-1964), introduced Kass to Smith, when Kass sought information about McClintock’s affiliation with the Maize Genetics Cooperation News Letter at the encouragement of former editor Coe (see Kass 2013ff.). Although Murphy had long ago left maize research, he had done his Ph.D. at Minnesota with one of the most prominent maize geneticists of his generation, Herbert K. Hayes, and continued his interest in the subject through the faculty in Plant Breeding (Murphy & Kass 2007, 2011). Having access to the early maize volumes led to cooperative efforts to expand the chronological list of materials related to maize cooperation (Coe & Kass 2005) and to provide his- torical perspectives on the cooperative spirit fostered at Cornell by Emerson (Coe 2001, Kass et al. 2005). Smith also tutored Kass in the reproductive biology of maize to further her understanding of the extensive field work required, and she introduced Kass to the cytogeneticists teaching in the Plant Breeding Department, who used slides prepared by McClintock for work reported in MNL (see Kass 2013ff.). Judy Singer has been an invaluable resource to this project, and has been a long time member of Cornell’s Depart- ment of Plant Breeding and Genetics. Singer facilitated all contacts for obtaining the photographs that appear in this book, and she designed and took the photo that appears on the back cover. Singer’s cooperative spirit is remi- niscent of the manner fostered by Plant Breeding Department Head Rollins A. Emerson. For many years, she has 3 worked towards the preservation of historical documents in this historically notable department, initiated by Dean Liberty Hyde Bailey in 1907 (Murphy & Kass 2007). Murphy, Kass, and Singer worked closely to save and identify documents for the history of Cornell’s Plant Breeding Department (Murphy & Kass 2007), which was subsumed into the School of Integrative Plant Science when it was established in 2014, and to deposit these documents for posterity in the Cornell Archives. In this tradition, and in celebration of the 90th Anniversary of the Maize Genetics Cooperation News Letters, the editors of this volume are pleased to present a digital record of the early Maize News Letters, founded at Cornell University by R.A. Emerson in April of 1929. References Cited Bostian, Carey Hoyt (1907-2000). North Carolina State College, Raleigh (now NCSU) https://en.wikipedia.org/ wiki/Carey_Hoyt_Bostian Bridges, C.B., and M. Demerec. 1934. Drosophila Information Service [DIS] 1(March): 1–88. [DIS 1, p. 2 mentions a letter sent to Drosophila geneticists on Nov. 10, 1933, reporting that Drosophila workers plan to establish a similar service to that of the maize workers (Excerpts of DIS No. 1 have been digitized beginning with p. 54). MNL 4, p. 2, Dec. 18, 1933, reports that the Drosophila workers have decided to start a cooperative group modeled after the one for maize.] Coe, Edward H. Jr. 2001. The origins of maize genetics. Nature Reviews Genetics Volume 2 (Nov. 1): 898–905 Coe & Kass 2005 (see Annotated Bibliography and Appendix II) Carter, T.C. et al. 1952. Nomenclature for Inbred Strains of Mice; Prepared by the committee on standardized no- menclature for inbred strains of Mice. Cancer Res 12:602-613. [Reference 1 states that the first Mouse News Letter was edited by L.C. Dunn at Columbia University. Subsequent issues were prepared by T.C. Carter, Hampstead, London. In this report there is no mention of Snell’s (1941) or Law’s (1948) previously published Mouse Genetics News.] Crow 1992 (see Annotated Bibliography) Dunn, L.C. (Ed.) 1949. Mouse News Letter Vol. 1. Columbia University; Issued twice annually (semiannual) [see Reference 1, p. 603, in Carter, T.C. et al. 1952. Cancer Res 12: 602-613.] Edgar, R., 1975 Worm Breeder’s Gazette, Vol. 1 (No 1. Dec. 1975), pp. 1–22. Santa Cruz, CA. [see also http:// wbg.wormbook.org/about/; http://dev.wormbook.org/wbg/archive/; online 2009, http://toddharris.net/ blog/2009/12/16/an-early-model-for-open-access-returns-say-hello-to-the-new-worm-breeders-gazette/] Fungal Genetics Reports (FGR). 2008--current. Published as an online resource by the Fungal Genetics Stock Center. Volumes 1 - 32 (1962 - 1985) were published as Neurospora Newsletter. From 1986 - 2007, FGR was continued as Fungal Genetics Newsletter, then Fungal Genetics Reports (2008-current), https://newprairiepress.org/fgr/ Gramene, The Rice Genetics Newsletter [RGN1] Volume 1, Number 1, 1984, http://archive.gramene.org/newslet- ters/rice_genetics/rgn1/v1conte.html Jones 1932, Vol. 1 (see Annotated Bibliography) Kass, L.B. 2001. Ethics in science: preparing students for their career. Plant Science Bulletin 47: (No. 2, Summer 2001): 42-48. [Available online at: http://botany.org/PlantScienceBulletin/psb-2001-47-2.php] Kass, Lee B. (Ed.). 2013ff. Perspectives on Nobel Laureate Barbara McClintock’s publications (1926-1984): A Com- panion Volume. The Internet-First University Press, Ithaca, NY. URI: http://hdl.handle.net/1813/34897 [online Dec. 30, 2013, updates 2014; 2016, Kass_Vol_III_Increments_v07Jun16_PRT.pdf (15.27Mb)] 4 Kass, Lee B. and Christophe Bonneuil. 2004. Mapping and seeing: Barbara McClintock and the linking of genetics and cytology in maize genetics, 1928-1935. Chap. 5, pp. 91-118, in Hans-Jörg Rheinberger and Jean-Paul Gaud- illiere (eds.), Classical Genetic Research and its Legacy: The Mapping Cultures of 20th Century Genetics. London: Routledge. Kass et al. 2005 (see Annotated Bibliography and Appendix I) Law, L.W. 1948. Mouse Genetics News, Journal of Heredity, Volume 39, Issue 10, 1 October 1948, pp. 300–308 [not free access]. Maize Genetics Cooperation News Letter (see Annotated Bibliography) Morgan 1932 (see Annotated Bibliography) Murphy, R.P. and L.B. Kass. 2011 (27 June). Evolution of Plant Breeding at Cornell University: A Centennial History, 1907-2006. Rev. ed. i-x, 178pp., Appendices, Photo Section. The Internet-First University Press, Ithaca, NY. URI: http://hdl.handle.net/1813/23087 Murphy, R.P. and L.B. Kass. 2007. Evolution of Plant Breeding at Cornell University: A Centennial History, 1907- 2006. Department of Plant Breeding & Genetics, Cornell University, Ithaca, NY, Pp. 1-98, Appendices A1-A98, Photo Section P1-P38. (July 2007). Röbbelen, Gerhard (Ed.) 1964. Arabidopsis Information Service (AIS) Volume 1, No. 1. September, 1964. https:// www.arabidopsis.org/ais/1964/index1964.html [In 1974 A.R. Kranz assumed editorship until 1990; electronic vol- umes available at: https://www.arabidopsis.org/ais/newaisvols.jsp; continued by The Arabidopsis Information Re- source (TAIR), https://www.arabidopsis.org/] Snell, G.D. [Ed.] 1941. Mouse genetic news, No. 1. Roscoe B. Jackson Memorial Laboratory, Bar Harbor, Maine. 18 p. (Mimeo.) [Issued November 1941, reissued November 1945-see Law 1948 for details] Zebrafish Science Monitor Volume 1 No. 1, July 1, 1991, https://zfin.org/zf_info/monitor/vol1/vol1.1.html#- FROM%20THE%20EDITOR; Published through August 14, 2000 (https://zfin.org/zf_info/monitor/mon.html) ZFIN NEWS, The Zebrafish Information Network, Volume 1, No. 1. Summer 2004 https://zfin.org/zf_info/news/ Newsletter_Summer04.pdf; “ZFIN NEWS” is the ZFIN Newsletter, published bi-annually at the University of Or- egon 5 6 Introduction to Maize Genetics Cooperation News Letter, Volume 1 (1929) The following pages offer a full page verbatim scan of the first MNL, sent to maize cooperators by R.A. Emerson on 12 April 1929 (Kass et al. 2005, Appendix I). The “Historical Notes on Maize Cooperation” listed on p. 56 of MNL 14 (1940) states that the mimeographed letter of April 12, 1929 is “considered News Letter 1” (see INTRODUC- TION). The scan was made by Ed Coe from the archived files of E.G. Anderson (See Coe & Kass 2005, Appendix II). 7 8 CORNELL UNIVERSITY ITHAC A» Ho Y. April 12s 1929 IT* Oh UNTO OS :ze o. You who attended the wcornf.Vbw in my hotel room at the time of the winter science meetings in hew York will recall that. I promised to prepare a summary of the published data involving linkage groups in maize9 to add my own unpublished data., and to send these records to each of you for criticism and the addition of such unpublished records as you may care to furnish me* I am now enclosing the records promised, but can claim no credit for having assembled them. Professor Eraser had, before leaving for a year in Europe, abstracted the available published papers. Mr.. Beadle has completed that work, has assembled my own unpub­ lished records, and has arranged all the tables and charts. I hope that each of you, whether or not 3rou attended the Hew York meeting, will send me such relevant data as you have not yet published, showing either linkage or independent inheri­ tance. In so far as you have data ready for publication, I prefer to receive a copy of your manuscript, but shall be glad to have also records which you are not ready to publish, if you care to send them. I agree not to publish any such data without your con­ sent and in any case to give proper credit. Any records sent, however, should be with the understanding that I am at liberty to use them in an early revision of the mimeographed sheets for dis­ tribution to other workers, pending the publication of the general linkage paper which I have been threatening to bring out for some years now. I indicated at New York that the records were too in­ complete to warrant publication now, a fact made strikingly obviou by the I *5,rainbowsn on the maps. The distribution of the data in mimeographed form should serve temporarily the needs of those actively studying maize genetics; and others can wait. The co­ ordination of effort agreed to in New York should go far toward straightening out many of the question marks in the next year or two. 9 In this connection, I add here, as a reminder, a list of those to whom linkage groups were parcelled out at How York, C­Wx group Eyster, Buckneli; Beadle, Cornell. R~0r group Lindstrom, Jenkins, Wentz, Ames. Su­Tu group BiTiersoa, Cornell.. B­Lg group Stadler, Missouri; McClintock, Cornell, Y - P l group ­ Bill, Cornell. p­Br group ­ Emerson, Cornell. Ra­Gl group ­ Brewbaker, Minnesota; Brun1 son, Manhattan; Eraser, Cornell. Bx­V group ­ Eyster, Bucknell; Jorgenson, Ohio; Li, Cornell, group ­ Hot assigned. group ­ Brink, Wisconsin; Li, Cornell. To those not at the Hew York meeting, it should he ex­ plained that this assignment of groups was, so far as possible, made in accordance with the expressed interests of those assuming the responsibilities entailed. It was far from our purpose to preempt groups for ourselves and thereby warn off other workers. Our purpose rather was to make sure that each known group woula be given immediate and adequate attention to the end that the not vexy exciting job of chromosome mapping may go forward^with some dis­ patch, thereby making possible an attack on certain important genetic problems now awaiting just such tools as accurate linkage Saps afford. It should go without saying therefore that the help of those of you v/ho were not at the Hew York conference will be welcomed. I suggest that those who have mode themselves respon­ sible for any group, request needed material directly from the workers most likely to have it, as indicated by the names in the last column of the table lor that group. We at Cornell shâ ­l be glad to furnish on request tester stocks in so far as our sornewhar limited supply will permit. It would doubtless be he3.pful if those who have particularly desirable testers for any group would proffer them to the ones who are primarily responsible for that group. Sincerely, R. A. Emerson 10 In the last column of the tables giving the linkage data for the several linkage groups, papers from which the records have keen sum­ marized are indicated "by author and year, hot all published data are included. For instances Rd, data are omitted when abundant back­cross data are available. Records credited to an author without indication of the year are unpublished. In general, unpublished data received in personal correspondence are net included, except when no publishes records are available. Such data are doubtless incomplete. It Is thought, therefore, that workers will prefer to add their complete data as of the spring of 19£0. X and Y in the column headings of the several tables indicate the dominant genes of the first column and x and y their respective r ec e ss ive allelomorphs. In the second column under the heading 15Link, phase11, C ­ coup­ ling and R = repulsion, Be ~ back­crossed and S ~ selfed. Bata presented in the table of three­point tests are included :. not additional to, data in the several group tables. The first col .mu of this table shows the genotype of one parent only, the other parous having obviously the respective allelomorphs of the genes of parent no. 1, The genotypes involved in columns 2 ­ 5 will be clear from the following illustration: Parental Parent combinations Region 1 Region 2 Regions ho. 1 ho. .1 ho, 2 ______________ ___________________ 1 and 2__ C sh Wx C sh Wx­c Sh wx C Sh wx­c sh Wx.C sh wx­e Sh Wx C Sh Wx­c sh vr. I Sh wx I Sh wx­i sh Wx I sh Wx­i Sh wx I Sh Wx­i sh wx I sh wx­i Sh ¥ Baps. ­ Ho attempt has been made to indicate map distance other than by observed cross­over percentages $ 3 mm. = 1 per cent crossing over. Starred genes (*) are those located with reasonable certainly5 others probably belong in the general region indicated. A gene tested with only one of the located genes is placed oppo­ site that gene at a distance determined by the cross­over percentage, its locus being approximately at one end or other of the "rainbow1. Independence of linkage groups.­ This chart shows what tests have been made between genes of anj one linkage group and those of other, presumably independent, group* Thus, there are records involving approximately 9900 individuals .tv :n selfed parents indicating independence between C or I and A and approximately 2000 individuals in back­cross progenies indicating independence of sh and A. It is obvious that the data are not ade­ quate to establish the independence of all the groups, and it is hope that other workers will have unpublished data to fill in some of the "holes"o As an example of the necessity of obtaining more nearly adequate data, a manuscript by Hayes and Brubaker (received after i­he stencils for the linkage tables had been cut) indicates that gl0~fu belong to the B­3g group, while Beadle*s unpublished records suggest that fi is in the C­wx group. The independence of these two groups is, therefore, quos t i0nab 1 e. 11 List.of Genes ar Argentia ­ finely striped leaf Eyster 1929 au^ Aurea chlorophyll­yellow plant Eyster 1929 au2 Aurea chlorophyll­yellow seedling Eyster 1929 ip Brown pericarp with a Meyers 192? C Colored aleuronc with A and R East and Heyes 1911 43 Dwarf plant Subtle (Unpub.j de15 Defective endosperm Brink 1927 hi­­­­ Ha yes and Eas t 1915 gl2 G lo s.a.y. s.oed 1 i ng . g^i Germless Eyster 1929 I Inhibitor for aleurone color East and Hayes 1911 pk Polkadot leaf Eyster 1929 a Virescent seedling Demerec 1924 V14 Virescent seedling Phipps (Unpub.) v15 Virescent seedling Phipps (Unpub.) n i White seedling Demerec 1926 WX ¥axy endosperm Collins 1909 yg Yellow­green plant Jenkins 1927 Notes pit The 1929 data of Eyster on pit are not consistent with his earlier data. He makes the statement in his 1929 paper that pk and ar show relatively close linkage— hence pk pro!ably lies on the wx side of G. ■̂̂ie naterial on which the d^ and w\^ counts were made, W11 •̂tlG C and R factors were segregating. Demerec states that a calculation of the recombination percentage with C would suggest that both d^ and were on the wx side of sh but that a calculation on such material could not be depended on. au^ The location of au^ to the right of sh is somewhat doubtful. Recombination values with C and sh are based on separate progenie So Neither au or au have been tested with yg for allelomorphism. 1 ^ v14 ^14 ­*­s known to be located in the C­sh­wx linkage group but the data (Phipps unpub.) are of such a nature that .a recom­ bination value cannot be calculated. 12 Genes Link. Ro. comb in a­ ! phase Humber of individuals cions X Y xy Xy xY xy Total Ho. | % i Authority J■ VUu ­VA. R Be 115 340 298 92 845 207 24.5 Breggar *18 C Be 858 310 O -L J- 7 pi 2260 621 77,5 Breggar 113 C Be 371 115 125 397 1008 240 23.8 Kempt on *719 C Be 2542 717 739 2710 6708 1456 21.7 Hutchison 522 42511 9388 22.1 Stabler *25 249663 67402 27.0 Collins and 302995 79314 26.2 (Kempton 727 V, SH G BC 4032 1 5 T ~T5214T035 SMS' 30T 3.6 Hutchison ? 22 C Be 10077 366 397 9866 20706 763 3.7 Eyster *29 R Be 638 21379 21096 672 43r,35 1310 3.0 Hutchison s22 "72849 2374 r 3.5 Sh ¥x R Be To31 r OT9T7~5S85 T48S~13855 3019 l"20.3 Hutchison *22 i oh C BC 9452 402 TOTT “196X5 786| 4.0 Hutchison '22 1 Wx [C Be "1487 584 547" 1520 4155 i TT3Ti 277X "Ttufchi son 5 22 R Be 7yo 2217 2283 792 6082 1582 26. 0 Hutchison ? 22 h 10220 2713 26.6 C V, R Be 3001 676 711 294 1981 594 RSOoO Lemerec ’2' n i l R 70 84 40 3 197 7± “ Bernerec *24 1 Pk C S* 128 o 54 ^ 56 244 2 Eyster *24 c s'L 148 5 128 92 373 2 Eyster *24 Sh Pk R ST 140 61 60 2 263 10 Eyster *24 ' R S> 382 173 173 11 739 24.5 Eyster *29 R Be3 73 363 366 70 872 143 16.4 Eyster *29 ^ x _ R 3 329 1621 138 8 637 j 22.8 Lemerec *26 ­l b WW 11 R S 487 193! 161 16 857 31.2 Lemerec 526C S 320 26 25 67 438 13.4 ­Lemerec *26 S Yg 0 s 30817 20.5 Jenkins J27 R S. 3885 23.0 Jenkins *27 R BC 10 57 52 7 126 17 13.5 Jenkins *27 Sh Yg R Be 193 546 429 99 1267 292 23.0 Jenkins *27 R S 2583 1­g2g1g2 1057 89 4941 28,6 Jenkins *27vi x Yg C Be Z§T ­J "297" 412 ~T39’5Y 586 r 42. 0 Jenkins *27 R Be 78 120 136 80 414 1518 38.2 Jenkins .271Q0T] nm A 41.1 Jenkins *27 ?"l5 Wx 0 S 4075 46r 1609 6145 19.4 Brink *27 Le1Fl Sh R S 2449 1146 1237 4832 16.5 Brink ’27 Yv Bp R Be 9| 56 49 9 123 18 14.6 Meyers *27 C; Ar R Be* 2178 4692 4166 1507 12543 3685 29.4 Eyster *29 Sh Ar R Be1* 1925 4763 4177 1221 12086 3146 26.0 Eyster * 29 Six Gu C S 2108 311 310 492 3221 21.6 Eyster *29 ­J hul c s' 546 79 638 305 1568 | 26. 5 Eyster *29 Sh AUp rR 340 133 146 ion 629 28.0s Eyster *29 Sh Gm^ c s 2693 301 258 702 3954~1 115.3 Eyster *29 15 V15. R 3̂ 297 128 139 2 566 | 2.9 Phipps Sh ­j F [r s^ 366 171 172 5 714 ­ „i— 20 Phipps----- rr--- ! _C and R segregating ­ 9i7 ratio \A, C and R segregating - 27^37 ratio 3Ratio corrected for germination "by author ^See Three­point test data ''Recombination value recalculated ­ author*s calculation given as 39.7 13 a) au ox 14 List of Genes df flint defective Lindstrom 1925 g Golden plant Lind sfrom 1918 gm2 Germle ss Dome re c 1926 lj­l Lineate ­ striped leaves Hemp ton 1920 Ii_L. Lutous seedlings Lindstrom 1917 12 Luteus seedlings Lindstrom 1925 nl Harrow­ler.f Erne r s o n (ITnpuh c Pg'l Pale­green seedling Brunson 1524 R Aleurone color East and Hayes S Spotted aleurone with Rrr Kempton 1919 vie Virescent seedling Phipps (Unpub.) v20 Viresccnt seedling Phipps (Unpub *) w2 White seedling Carver 1924 15 Re combi nr*­* I Ge nc s Link* Number of individuals ■ tions X Y phr se X Y X y 1 x Y x y Total No * _z_. Authority R G C Be 200 55 58 174 487 113 23*2 Lindstrom *17 & *18 C Be 227 36 33 195 491 69 14*1 Emerson R Be 29 81 86 18 214 47 22.0 Lindstrom *18 R Be 18 117 156 28 319 46 14*4 Emerson 1 1511 275 18 * 2 R C S 303 2~1 5 121 431 1 • 61 Lindstrom •21 G R Be 8 35 21 5 69 13 18.8 Lindstrom *13 R Pg. C B n 1907 .300 1053 686 3946 23.3 Brunson *241 R S 1199 506 445 32 2182 27.2 Brunson *24 G Pgl C 8 “638 33 57 146 890 14.6 We nt z Lil Pgl R S 194 71 265 45 Brunson *24 R “ Wo G s 1329 171 202 402 2104 18.5 Carver *24 C s 648 74 81 157 960 17.8 Lindstrom *24 R s 43 16 22 2 83 30.8 Carver *24 EtX R s 815 210 10 1035 Lindstrom *25 R s3 585 348 84 1017 Lindstrom *85 R 560 318 70 948 Lindstrom *25 R s5 380 402 115 897 22.0 Lindstrom *25 R L2 R s ~ m e ~ 405 473 69 1893 33.9 Lindstrom *2d C s1 837 197 582 277 1893 35.4 Lindstrom 725 R Gmo R s 2239 784 976 84 4083 31 Dome rec *26 R S' 6876 2947 1182 90 11095 27 Wentz r: '•flli2 VJT R s "28X0 ~ 3'6 S3~ DO ± Wentz Gm2 Pgl R s 835 255 ' 1090 50 ± We nt z R L 51 15 43 93 202 20 Phippsr R VPO c Bcfc 77 10 80 152 319 12.5 Phipps G Li^ R Be 148 817 924 111 2000 259 13*0 Hutchison R Li^ C Be 208 74 86 138 506 160 31*6 Hutchi son C Be6 460 191 282 374 6517 191 29*3 Hutchison 1157 351 30.3 ru%* N1 R Be 69 389 382 49 889 118 13.3 Emerson R NX C Be 219 93 116 191 619 209 33.8 Emerson 11928 data indicate complete linkage mid R segregating ­ 9 s 7 fileurone ratio 3W^ and wg segregating \̂7g and segregat _ng w2 cinĉ w3 segregating and R segregating 1First two classes only Note s df Lindstrom states that df and wo are very closely linked ' but presents no data, S Kempton (1919) postulated this spotting factors located so as to give about 12.5/& re comb inat ions 1 with R* Emerson (Unpubc) has additional evidence in support of this assumption. 16 R l/^V U°l3 / ^ M ii 17 List of Genes e­' Ocm de­̂ Defective endosperm 11a nge 1 b d o rf /19 2 'v do6 Defective endosperm Mange1s dorf 1926 dc16 Defective endosperm Wentz 1925 ,̂ JorK,o Ga Gamete ­ pollen tube growth Mange 1 s do rf/1925 gex Premature germination Mangelsdorf 1926 su Sugary endosperm East and Hayes 1911 x S5 Tasscl­secd Emerson (Unpub ­) Tu Tunicate ear Collins 1917 wl White­­base leaf Stroman 1925 Linkage Lata ! Re c omb i na ­ Gene Link, Humber of individuals t ions X Y phase X Y X y x Y x y Total HO a % Authority Su Tu C S 113 4 7 25 149 8,3 P o ne s & Gallnstegui * 2 C Dc 430H 175 169 406 1180 344 29,1 Eystcr ’21 C Be 612 290 208 562 1672 498 29,8 Emerson R Be 1031 2498 2093 . 807 6429 1838 28.6 Eyster *22 R Be 63 215 164 57 499 120 24.0 Erne r s o n 9780 2800 28 • 6 Su Wl R S 44 19 11 1 75 25 ­ 0 Stroman ’24 R S 4492 2018 1961 93 8564 22.0 Carver '27 Dele Su C S 20622 453 7201 28276 * 3.2 Wentz *25 Su V8 C S 940 214 179 148 1481 ­ 32.4 Bernerec T26 Tu C S 450 1 Lethal 451 41 Phipps De1 Su R S 601 238 247 64 1150 . 39 Mangelsdorf & JL Pone s '25 De 6 Su R S 204“ 92 ­ 296 26 Mange1sd orf ? 25 Ge­̂ Su R s 1218 474 1692 40 Mangelsdorf *26 Su TSr­ C Be 578 41 42 457 1118 83 7.4 Emerson5 Tsr rpr, 1 L L Be 49 166 115 48 378 97 25.7 Emerson5 R Petes Ge­i1 6c is used instead of su for su°g ar1y7 defective of Wentz, Vq is very near Tu but whether to the left or right is unknown­ Ga is to the left of su because it disturbs the Tu­tu ratio very little if at all in pedigrees in which it disturbs the Su­su ratio materially (Emerson, Unpub,), den is presumably to the left of Ga, because Ga is between dc and su (Mangelsdorf and Pones 1925). 18 'O\ Z ­6 a, tfTs ur c; • , / d ^ wu/. ; / *»6 / ­x 19 List of Genes ".DD Intensifier of plant color Emerson 1918 Ig Ligulele ss Emerson 1912 sk Bilkless jone s 1925 ts^ Tassel­seed. Emerson 1920 t4 Virescent seedling Domeree 1924 Linkage Data i Recombina­ Genes Linkc jITumber of individuals tions X Y phase ! X Y XJSL x Y x y Total Bo. % Authority B Ig C Be 240 134 102 243 719 236 32.8 Emerson *18 C Be 642 291 282 620 1835 573 31.2 Emerson C Be 2487 1469 1557 2609 8122 3026 37.2 Emerson & Hutchison T 21 R Be 498 1085 103/ 504 3124 1002 32.1 Emerson 13800 4837 35.0 Lg Ts­, C Be 117 52 72 74 315 124 39.4 Emerson R Be 51 65 64 42 222 93 41.9 Emerson ~53T~~2T7~ 40.4 B G Be 113 24 21 110 268 45 16.8 Demerec *24 v4 Ig R Be 412 501 521 366 1800 778 43.2 Demerec ?24 B Sk C Be 1332 97 106 1226 2761 203 7.4 Anderson R Be 2 82 66 6 156 8 5.1 Andersen '“SUIT 21T 7.2 Eg BE ~ m B c ~ I F T 288“ 315 167 957 354 37.0 Anderson 148 60 67 133 408 12/ 31.1 Anderson 1365 481 35.2 20 ­st? B * a 4 21 List of Genes Bh Blotched aacurone with A c R Emerson (Unpub fi Pine streaked leaves Anderson 1922 PI Purple plant color Emerson 1918 sm Salmon silks Anderson 1921 Te Vire scent soe dling Carver 1927 V7 Virescent seedling Carver 1927 W1 White seedling Stroman 1924 w5 White seedling with wg Lemerec 1924 White­ seedling with Wg Lome re$ 192 4i Linkage Lata Re combina­ Gene s Link*! Number of individuals tions X Y pi? Clse X Y X y x Y x y PotaT" No. Author it ;y Y PI c Be 79 22 28 71 ! 200 50 25*0 Emerson ’18 545 221 234 506 1506 455 30.2 Anderson ’21 80 51 3C 55 216 31 37.5 Anderson 173 46 59 176 49 4 105 23.1 Hutchisqn R Be 367 880 8Q7 372 2516 739 29.4 Anderson 5.21 135 398 374 118 1025 253 24.7 Anderson 5917 1633 28.5 PI Sm C Be 1076 145 146 994 2361 291 12.3 Anderson ’21 84 1014 971 76 2145 160 7.5 Anderson Y2I 4506 451 lo.o Y Pi 'Tt Be ^“33351 0 ' many Anderson** * P2 Y "IT kOJ ~37 35 54 376 24.3 Demerec T23 (W5 12 (24.3Y s' 349 eo 33 454 Pemerec ’23 (W* 024.5 Y 5*T "1020“" 259 191 1707 35 !Lindstrom ’24 C s 1132 321 c* 34­7 175 1975 42 Stroman *24 R kj 456 181 186 41 864 42 Stroman ’24 Y V6 R s 467 2U!T 209 12 913 23 Carver 127'J V? C s 592 149 1 78 79 998 42 Carver ’27 c s'z 445 277 106 116 944 36 Carver ’27 Ye v7 R s V5T~ 179 23V 913“ 42 Carver *27 Bh Y C Be 144 51 118 2103 523 169 32.3 Anderson Bh P I C Be 58 1 26 473 132 1.7** Andersen lwn and wg duplicate genes ^Segregating for another v ­ not linked ^Probably part of this class actually Bh '^Prcm Bh class Notes m­jj Stroman presents data which he interprets as showing r linkage between m­j and mg and also between and Y. m2) His data are sufficiently extensive only to suggest that these factors may beD.ong to this links,go group* 22 u urcG? \ • ;/ j u■7\{ \ \ ti lOy Oi ?'fth 23 List ox Genes Bn Br c wn a 1 e ux 0 no Kva ka 1 \ 19 2 4 gip Glossy seedling ILvakan 1924 in Intensifier of alourone Praser 1924 Pgp Pale­green s0cdl1ng Bemerec 1925 ra Ramo sa Gernert 1912 si Slashed seedling Haye s and Br evbaker 1926 sr0 Striate ­ striped leaf Bruns 0n (Unpub,) Virescent Demerec 192^ Linkage Data Recombina­ 9 ones Link, Humber of individuals tions 1 Y phase X Y l y . x Y x y To tal Ho. r /C°7 Authority'1 B­o Sla C Be 177 63 54 192 486 117 24.1 Kvakan * 2 4 ­ Gii v& C Be 106 9 6 120 241 15 6.2 Kvakan * Bu V5 C Be 83 31 29 98 241 60 24.9 Kvakan *24 Bn Ra C Be 169 104 100 161 534 204 38.2 Kvakan *24 Bn Pg1 C S 203 8 5 65 281 4.5 Dome re c 125 G1­, Sr 2 R Be 97 289 342 63 791 160 20.2 Brunson Rotes si Hayes and Brev/baker state that si belongs to this linkage group, Y2I Hayes and Brev/baker present data showing a linkage YpJ between two factors for yellow endosperm (Yg and Yp) and a glossy seedling factor. Since the relation of the glossy character to gl­ is net evident? the placing of these two genes in this linkage group would appear uncertain. 24 25 List of Genes bm Brown midrib Eyster 1926 bv Brevis ­ semi­dwarf plant Suttlc (Unpub.) f 2 Fine striped leaves Eyster 1926 Pr Purple alcurone East and Hayes : SC-,J- Scarred endosperm Eyster 1926 tn Tiny plant Eyster 1926 y2 Yirescent seedling Bemere c 1924 Yirescent seedling Bernerco 1924v3 v12 Yirescent seedling Phipps (UnpubO yg Yellow green Eyster 1926 ys Yellow­stripe Beadle 1929 Linkage Bata Recombina­ Genes Link. Number of individuals tions X Y phase X Y X y x Y x y Total Ho. C7__ /£._ Authority Pr Ypr --.j su Tu t s i U sk 3 lg y PI sm wl A 99 20. 5 48 99 9 6 2 80 1 12 13 op f i i 10 10 15 15 y­­ ~13reT~l[— "S"t' 2 2 5 5 A 1 *4 10 3 4 5 1 na L 5. 2 £ 123 2 J3 8 1 yp: 1 3 ft 5 3 ; Pr 8 5 20 G 1 5 3 1 •1— 2 ? C 11 13 2 5 V2 2 3 r5" 8 1 13 34 14 /O 1 4 *Tv;3 • '“ " Xto 8 6 4 1 C’7h 4 " I 4 11 5 2 8 r5nmm S I 3 3 3 2 5 p 62 7 4 4 7 6* 26cr 4 10 3 12 5 4 9 5 2 9 *t 5 1 1 Bn 26 14 14 9 6 29 2 p 41 6 3 I dr;U-1 ..... r§ 7 6 4 16 3 3 10 7 4 4 0 8 7 in 45 P 8 3 12 5 6 7 6 1 30 7 p, 18 23 c ts2 1 3 2 r R 3 7' 7" or | 5 3 16 1 fl 9_ 2 15 2 6 2 3 y 9 8 12 15 4 2 1C 1 10 13 1 14 14 10 pi 6 5 6 12 5 7 S 4 11 3 14 44 19 sm 1 t S l 5 V/ 12 7 12 8 sk 3 13 4 B 33 11 46 1 7 7 5 13 19 figures in table represent lg it 19. 15 55 3 10 7 10 21 23 approximately the number of hundreds of individuals counted, the counts r1>c, 2 4 suggesting independent inheritance. °5 SU 50 71 5 2 5 3 Counts on backcross progenies are Tu 9 9 5 3 distinguished by an underscore from counts from self pollinations. R 17 23 6 ! fih 1 "3 nl 3 3 1^1 8 v18 2 2 V20 2“ Continued on next page 33 j cn i «-* y e c i s.h \ :x VX auu I R nl X il '• X1 uO "̂ nc>r- su Tu t s i p Bn v5 ra d­j pg2 er Pr Vg v3 v-̂ 9 bv -.j U sk 3 lg y PI sm wl t s g b r A 99 20. 5 48 99 9 6 2 80 1 12 op y­­ 2 2 5 5 A 13 f i i 10 10 15 15 ~13reT~l[— "S"t' 1 *4 10 3 4 5 1 na L 5. 2 £ 123 2 J3 8 1 yp: 1 3 ft 5 3 ; Pr 8 5 20 G 1 5 3 1 •1— 2 ? C 11 13 2 5 V2 2 3 r5" 8 1 *Tv;"3 13 34 14 /O 1 4 • '“Xtoh 8 6 4 1C’7 4 " I 4 11 5 2 8 r5nmm S I 3 3 3 2 5 p 62 7 4 4 7 6* 26cr 4 10 3 12 5 4 9 5 2 9 *t 5 1 1 Bn 26 14 14 9 6 29 2 p 41 6 3 r;U Id-1 r§ 7 6 4 16 3 3 10 .....7 4 4 0 8 7 in 45 P 8 3 12 5 6 7 6 1 30 7 p, 18 23 c ts2 1 3 2 r R 3 7' 7" or | 5 3 16 1 fl 9_ 2 15 2 6 2 3 y 9 8 12 15 4 2 1C 1 10 13 1 14 14 10 pi 6 5 6 12 5 7 S 4 11 3 14 44 19 sm 1 t S l 5 V/ 12 7 12 8 sk 3 13 4 B 33 11 46 1 7 7 5 13 19 figures in table represent lg it 19. 15 55 3 10 7 10 21 23 approximately the number of hundreds of individuals counted, the counts r1>c, °5 2 4 suggesting independent inheritance. SU 50 71 5 2 5 3 Counts on backcross progenies are Tu 9 9 5 3 distinguished by an underscore from counts from self pollinations. R 17 23 6 ! fih 1 "3 nl 3 3 1^1 8 v18 2 2 V20 2“ Continued from previous page 34 j cn i «-* LITERATURE ON LINKAGE IN HHI2E In general, only papers containing data on the linkage or independence of factors in knov/n linkage groups are listed. Anderson, E. G. - The inheritance of salnon silk color in naize. Cornell Univ. Agric• Exp, Sta. Hen. 48: 539-554. 1921» - Heritable characters of naize. XI. Pino streaked leaves. Jour. Heredity 13: 91-92. 1922. ______________ - Pericarp studies in naize. II. The allele - norphisn of a series of factors for pc-ricarp color. Genetics 442-453. 1924. _______________ - Genetic factors for yellow ondospem color in naize. Papers Mich. Acad. Science, Arts & Letters 4: 51-54. 1924. .______________ and Emerson, R. A. - Pericarp studies in naize. I. The inheritance of pericarp colors. Genetics 8s. 466-476. 1923. Beadle, G. Y7. - Yellow stripe - a factor for chlorophyll deficiency in naize located in the Pr pr chronosonc. Aner. Nat. 63: 139-151. 1929. Breggcr, T. - Linkage in naize: The C alcurone factor and waxy endosperm. Aner. Nat. 52: 57-61. 1918. Brink, R. A. - A lethal nutation in naize caffecting the seed. Aner. Nat. 61: 52£*-530. 1927* Brunson, A. M. - The inheritance of a lethal pale green seedling character in naize. Cornell Univ. Agric. Exp. Sta. Men. 72: 5-22. 1924. Carver, W. A. - The genetic relation of endosperm and chlorophyll characters in naize. Proc. Iov/a Acad. Sci. 31: 129. 1924. (A short note without data in which it is stated that brindled, a chlcrcphyll defect, shov/s linkage with sw- with about 26 % of re combinat ions (j . ___________ _ - A genetic study of certain chlorophyll deficiencies in naize. Genetics 12: 415-440. 1927. Collins, G. N. - Gametic coupling as a cause of correlations. Aner. Nat. 46: 559-590. 1912. ____________ _ - Mosaic coherence of characters in seeds of maize. U.S.D.A. B.P.r. Circ. 132: 19-21. 1913. _ ____________ - Hybrids of Zea tunicata and Zea ranosa. Proc. Nat. Acad. Sci. 3: 345-349. 1917. ______________ - Hybrids of Zea ranosa and Zea tunicata. Jcur. Agric. Res. 9: 383-395. 1917. _ ___ _ _____ _ Kenptcn, J. H. - Inheritance of waxy endospern in hybrids of Chinese naize. IV. Conference internat de genctique (Paris). Cenpt. rend. 1911: 347-356. 1913. ----- -------- —_- Inheritance cf waxy endosperm m hybrids with sweet corn. U.S.D.A. B.P.I. Circ. 120: 21-27. 1913. ­­­­­­­­ ­ a:lc ______________ ­ Inheritance cf endospern textu't m sweet X waxy hybrids of naize. Aner. Nat. 48: 584~&9& 35 Collins j G. IT. and Kempt on, J. H. ­ Variability in the linkage of two seed characters of maize. U.S.D.A. Bui. 1468; 64. 1927. Demerec, M. ­ Inheritance of white seedlings in maize* Genetics 8; 561­593. 1923. ________ ­ Genetic relations of five factor pairs for vircscent seedlings in maize. IT. Y. (Cornell) Agric. Exp. Sta0 Mem. 84" 3­38. 1924. ___ _______ ­ inheritance of pa^o green seedlings in maize. Genetics 10? 3 1 8 ­x4. 1925. ­ Botes on linkages In maize. Timer. Bat. 60; 172­176. 1926. East, E. Mo ­ Inheritance of color in the aleurcne cells of maize. Amer. Bat. 46; 363­365. 1912. ___________ and Hayes, H. K. ­ I meritance in maize. Ccnn. Agric. Exp. Sta. Bui. 167; 1­142. 1911. Emerson, R. A. ­ Genetic correlation and spuricus allelomorphism in maize. Beh. Agric. Exp. Sta. Ann. Rept. 24: 58­90. 1911. ______________ ­ The inheritance of the ligule and auricles of corn leaves. Boh. Agric. Exp* Sta. Rept. 25: 81­88. 1912. ______________ ­ A fifth pair of factors, A aL, for aleurcne color in maize, and its relation to the C. c_ cand R r_ pairs. Cornell Univ* Agric. Exp. Sta. Mem. 16; 231­289, 1918. ________________ ­ Heritable characters of maize. II. Pistillate­ flowered maize plants. Jour. Heredity 11: 65­76. 1920. ______________ ­ The genetic relations of plant colors in maize. Cornell Univ. Agric. Exp. Sta. Mem. 39: 7­156. 1921. ______________ ­ Aberrant endosperm development as a means of dis­ tinguishing linkage groups in maize. Tmer. Bat. 58; 272­277. 1924. ______________ ­ A possible case of selective fertilization in maize hybrids. Abstract in Anat. Rec. 29: 136. 1924* ______________ and Emerson, Sterling H. ­ Genetic interrelations of two andromonoecic­us types of maize, dwarf and anther ear. Genetics 7s 202­236. 1922. ___________ __ and Hvhchison, C. B. ­ The relative frequency of crossing over in micrespore and in megaspore development in maize. Genetics 6: 417­432. 1921. Eyster, W. H. ­ The linkage relations between the factors for tuni­ cate ear and starchy­sugary endosperm in maize. Genetics 6; 209­240» 1921. ­ Inheritance of zigzag culms in maize. Genetics 7; 559­567. 1922. ____________ ­ The intensity of linkage between the factors for sugary endosperm and for tunicate ears, and the relative fre­ quency of their crossing over in microspore and megaspore development. Genetics 7s 597­601. 1922. - A primitive sperophyte in maize. Ancr. Jour. Bet* •; V~ n ~7T -t o o / J - a ! — _L !± » l_ (f 36 Eyster, W» H. ­ Heritable characters of maize* Polkadot leaves. Jour. Heredity 15s 397­400. 1924* ­ Chronesone VIII in maize* Science 64; 22* 1926. _____________­ Five new gene®' in chrcnosome 1 in maize• Ztsch* f* Ind. Ah. u Vererb* 59; 105­130* 1929. Fraser, A. C. ­ Heritable characters of maize ­ XVII*' Intensified red and purple aleurone color* Jour. Heredity 15s 119­125. 1924* Hayes, H. Eh and Brewbaker, H. B. ­ Factors for color of aleurone and endosperm in maize* Jour* Ane r. Soc. Agron. 18 (9 ) % 761­767* "1926» ____________and _____ _;______­ Glossy seedlings in maize. Aner* Hat. 62s 228­235* 1928. ____________ and East, 33. M. ­ Further experiments on inheritance in maize* Conn. Agric. Exp. Sta* Bui. 188s 1­31. 1915* Hutchison, C. B. ­ Heritable characters of maize* VII* Shrunken endosperm. Jour. Heredity 12s 76­83. 1921* ________________ ­ The linkage of certain aleurone and endosperm factors in maize, and their relation to other linkage groups. Cornell Univ. Agric* E^p. Sta. Men* 60: 1425­1473. 1922. Inner, F. H* ­ The inheritance cf reaction to Ustilago /Zeae in maize. Univ. of Minn. Tech. Bui. 51: 62. 1927. Jenkins, M. T. ­ A factor for yellow­green chlorophyll color in maize and its linkage relations. Genetics 12; 492­518. 1927. Jones, D. F. ­ Heritable characters of maize XXIII ­ Silkless. Jour. Heredity 16s 339­341* 1925. ____ __ and Mangelsdorf, P. C. ­ The expression of Mendelian factors in the ganetophyte cf maize* (Paper given at Kansas meetings of A* A* A. S’., Dec., 1925). Anat. Rec. 31s 351. 1925 ____________ and Gallastegui, C. A. ­ Some factor relations in maize with reference tc linkage. Amer. Hat. 53s 239­246. 3.919 Kenpton, J. H. ­ A correlation between endosperm color and albinism in maize* Jour. wash. Acad. Sci. 7t 146­149. 1917. ______________ ­ Inheritance of spotted aleurone color in hybrids of Chinese maize# Genetics 4s 261­274. 1919. ______________ ­ Heritable characters of maize* V* Adherence. Jour. Heredity 11s 317­322* 1920* __________ ___ * Linkage between brachytic culms and pericarp and ccb color in maize. Jour. Wash. Acad. Sci. II; 13­20. 1921* ­' Linkage between brachysm and adherence in maize, /mier. Hat. 56: 461­464. 1922. ______________ ­ Heritable characters of maize. XVI. Dead leaf margins. Jour. Heredity 14s. 349­351. 1923* ­ Inheritance of dwarfing in maize. Jour. Agric. Res. 25; 297­321. 1923. Kvakan, P» ­ Tne inheritance of brown aleurone in maize. H. Y. (Cornell) Agric. Exp* Sta. Men. 83: 3­22. 1924* 37 Lindstron? E. W. ­ Linkage in maize: alourone and chlorophyll factors* frier. Hat. 51? 225­237. 1917. _______________ ­ Chlorophyll inheritance in naize. Cornell Univ* Agric. Exp. Sta. Mon. 13s 7­68. 1918* ­ Chlorophyll factors of naize* Jour* Heredity 11? 269­277« 1920. ____ “ Concerning the inheritance of green and yellow pigments in naize seedlings* Genetics 6: 91­110. 1921* ______ ­ Hereditable cliarr^ters cf naize XIII* Endosperm. defects ­ sweet defective and iAint defective* Jour* Heredity 14; 126­135. 1923 * ­ Genetic research with maize* Genetics 5; 327­356* 1923* ______________ ­ Complementary genes for chlorophyll development In maize and their linkage relations. Genetics 9; 305­326* 1924. _______________ ­ Genetic factors for yellow pigment in naize and their linkage relations. Genetics 10: 442­455. 1925. Mangelsdorf, P. C. ­ The genetics and morphology of some endosperm characters in maize* conn. Agric. Exp. Sta. Bui. 279; 513­ 614. 1926* _______________ _ _ and Jones, D. B. ­ The expression of Mendelian factors in the gametophyte of maize. Genetics 11: 423­455. 1926* Meyers, Marion T. ­ A second recessive factor for hrown pericarp In naize* Ohio Jour, of Science XXVII: 295­300* 1927* Phipps, I* E* ­ Heritable characters in maize* XXXI. Tassel seed­4* Jour. Heredity 19: 399­404. 1928* Stadlor, L. J. ­Variation in the Intensity cf linkage in maize. Arne r . Hat* 59: 366­370. 1925* ______________ ­ The variability of crossing over in maize. Genetics 11: 1­37. 1926. Stronan, G. H. ­ Genetic relations of chlorophyll and anthocyanin seedling characters in maize* Genetics 9: 91­123. 1924. _______________ ­ The Inheritance of certain chlorophyll characters in maize* Genetics 9s 493­512. 1924* Webber, H* J. ­ Correlation of characters in plant breeding* Aner* Breeders* Assoc. Rept* 2: 73­83. 1906. Wentz, J. B e. ­ Linkage between sweet­clefcctive and sugary endosperm in maize* Genetics 10; 395­401* 1925. 38 39 40 Introduction to Maize Genetics Cooperation News Letters, Volumes 2-14 (1932-1940) The following pages offer verbatim scans of the first set of bound MNL Volumes 2-14 (1932-1940) numbered by hand in pencil, beginning with October 1932, labeled “Vol. 2” (MNL 2; Coe & Kass 2005, Appendix II; see also Kass et al. 2005, Appendix I). The binding on the first set of bound News Letters clearly shows that 1932 was con- sidered to be MNL Vol. 2 (see image on back cover). MNL Volumes 2-14 are arranged below sequentially, numbered as per Emerson’s system (MNL 14:56, 1940), and inter-leafed with calls and other items as found in the Plant Breeding bound volumes (Scanning of MNL bound volumes was arranged by Michael Cook). Not included here is the “second folder” of Linkage data mentioned by Emerson in his Historical Summary (MNL 14:56, 1940). That document was among the papers of E.G. Anderson and also in the archives of the Rockefeller Foundation (Kass et al. 2005, Appendix I; Coe & Kass 2005, Appendix II). Note that both Emerson and Beadle sent many communications to maize cooperators prior to issuing MNL Vol. 2, 1932 (Coe & Kass 2005, Appendix II). Marcus Rhoades assumed editorship of the MNL as of October 5th 1932. Succeeding editors through 1940 were R.A. Emerson, Derald Langham, Emerson then Allan C. Fraser. 41 MAIZE GENETICS COOPERATION NEWS LETTER 2 1932 Department of Plant Breeding Cornell University Ithaca, N. Y. 42 M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A . N E W Y O R K October 5* 1952 To Corn Geneticists Enclosed with this is a report of the meeting of corn geneticists held at Ithaca at the time of the Genetics Congress and a report of a committee provided for at that meeting. In accordance with the action taken by the -hole group and by the committee, it is requested that, as soon as convenient, you send to the undersigned a small quantity of seed of any stocks which you think may be useful to other workers now or which should be maintained for future use. As these lots of seed are received, a record of them will be made and later sent to all of you so that you rnay know what is available. As an illustration of combinations of genes such as should be available for distribution, a list of types now in our possession at Cornell is given below. You should not fail to send material even tho it duplicates stocks in this list 1. lg-gl2-b-v4 7. lg g ar na-ts4 Bn-ra-v^ 8. p-(Tsgt5£)-(Ff)-(Br br)-an 5* Bn-gl-̂ -v̂ 9. A-j-na-cr gl^-v^ ¥-Pl 4. y-Pi-al 10. 3 E-lg Y-Pl C rr pr 5. a-j_ P sh v*x lg f^ 11. P-br-f-an 6. A B PI lg sh wx y 12. P-br-f-brn^ A limited supply of trfsomic seed is available for the b-lg, a-nq, pr-v£, Y-Pl, ra-gl-^ j, c-wx and r-g linkage groups. Ye shall be glad to supply samples of this seed to the different individuals charged with the responsibility of the various groups. If the demand is not too great we shall try to supply all requests for trisomic seed. If your v;ork requires some unusual set-up or if you want better material of certain types than you now have, please indicate your needs at once. Tnese requests will then be circulated from this office. As tn illustration of what is in mine here, Emerson wants an early maturing stock involving green-striped. He also desires the combination a&herent-enther ear. A. la. Ahoades, Sec’y 43 V o t . ^ Report of a meeting held during the Genetics congress on August 26th by those interested in corn genetics - M. M. Rhoades - The meeting v:as called to order by Dr = R Emerson Approximately 45 individuals veers present. Tiie following resolutions were discussed and favorably acted upon: - 1. That the dropping of the second letter in bi-literal symbols to form a subscript be condemned as confusing and unsat- isf actory . 2. That some place be designated as a ’clearing house’ to assist in the assigning of appropriate names and symbols for char- acters and genes. Cornell was chosen as the institution '/here the records will be kept and help given in the assigning of symbols. An example of how this ’clearing house’ may be expected to function is as follows:- Two individuals, A and B, are working on glossy seedlings. A reports he has 5 and 3 reports he has 4 new glossy seedlings. A will then be assigned from glA to glc< and B \ ill be assigned from gig to glpp. This should avoid the confusion that arises when two investigators use the same symbols for different genes. 0. That a repository be formed for the storing ana d1ssem- inating of new genes and of desirable multiple factor combinations, and that : list of such genes and combinations be furnished those interested from time to time. 4. That the geneticists refrain from designating the linkage- groups by numbers until the cytologists agree to the size secuence of the different members of the haploid set. 5. That a committee be appointed by Dr. Emerson to consider the problems connected v/ith the maintenance of a central seed re- pository. The report of the committee follows:- In accordance with the action noted above a committee was appointed consisting of Brink, Jones, hangelsdorf, btadler, and Emerson (chairman). The committee met and took action as follows 1. The genetics group at Cornell, with M. h. Rhoades in charge, is to act as custodian of these stocks. 2. The custodian is to receive from the several workers seed of any stocks involving new characters considered by the finder as worth saving and certainly any such characters the linkage of which is known, also particularly useful combinations of genes in the several groups, etc. 44 o. The custodian will furnish those interested a list of the stocks received. 4. He will distribute on request small lots of particular- stocks to workers having need of them. 5. The custodian will see that viable seed of these stocks is provided at least every three or four years by those charged with growing them. 6. The finder of a new character is expected to maintain the stock or to notify the custodian that he can not do so. Those assuming responsibility for particular groups will maintain stocks involving all the genes of those groups and will endeavor to build up desirable combinations of genes of the particular groups. 7. The following assignment of groups was made by the com- mittee:- Group 1 . P~br ...... Emerson Group 2 . — ” JL */1 • • • • • • • Beadle Group o . q • • « • • • • Brink Group 4 . U i- LI 9 9 9 • O o * Jones Group b . pr-vo • Burnh- m Group 6 . Y-Pl " Stabler Group 7. ££ -i- X* O- 9 0 0 0 9 0 9 Jenkins JL Group 8 . , j 0 0 9 9 9 9 9 Sprsgue Group 9. rw «.,.,ry» ■/ v • « • • • • t Eyster Group 1 0 . ■il • • • • • • • Lindstrom Any of the above who cannot assume or continue responsibilit for the group assigned him is to notify the custodian at once. It is to be understoon that anyone may begin or continue work with any group whether or not it has been assigned to him. The purpose is not so much to pV 9 V ent duplication as to insure that no group is neglect ad. It io .o>:pected? however, that hen two or more are interested in the same group, they will work in close cooperation! R. A. Emerson (chairman) 45 MAIZE GENETICS COOPERATION NEWS LETTER 3 January 23, 1933 The data presented here are not to be used in publications without the consent of the authors. Department of Plant Breeding Cornell University Ithaca, N. Y. 46 M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A , N E W Y O R K December 12, 19 To Id&ize Geneticists if you have any good tester combinations you v-ish to send in so that they may be made available for the whole group or if there is any combination of genes you would like to have, will you please notify us here at Cornell so that we may list your contributions and wants in the corn-letter which will come out in the near future. January 1st has been set as the dead line for receipt of material to be included in the letter. Will you please cooperate with us so that we can make this cooperative affair a real service to all concerned. We plan to include in the letter a summary of the technic employed by the Russian physiologist, Lysenko in his "bpringefication" of corn. If any of you have this year's linkage data which could be added to the linkage summary, we shall be glad to receive them at once. The summary is in pre- paration for publication. Cincerely yours, 47 N e w Y o r k S t a t e C o l l e g e o f A g r i c u l t u r e a t C o r n e l l U n i v e r s i t y C o r n e l l U n i v e r s i t y A g r i c u l t u r a l E x p e r i m e n t S t a t i o n I T H A C A , N. Y . D E P A R T M E N T O F P L A N T B R E E D I N G \r»t. z J n u ary 1933 To maize geneticists :- We are including in this report an inventory of all maize characters whose description has either been published or called to our attention. We are also including a summary of the tech- nique employed by Lyssenko in his 'Jarovization’ of corn. Demerec was kind enough to make the translation from the Russian. The response of the maize geneticists to the two letters from this office asking for their cooperation in establishing a clearing house and central repository has been good. Either seed or the statement that certain stocks were available and would be sent later has been received from the following institutions: Wisconsin, Texas A. and M., Missouri, Carnegie Institution, U. S. Department of Agriculture, Connecticut Agricultural Experi- ment Station, California Institute of Technology, Minnesota, Ames, Bucknell and Cornell. A list of these stocks is included in this report. The following wants have been received: 1. Related stocks homozygous for Ga ana ga. Sprague. S. A multiple recessive stock for each chromosome involving as great a map distance as possible with genes so situated as to reduce undetected double crossovers to a minimum. Sprague. 3. Variegated pericarp material from different sources. Whenever possible variegated/red cob white combination is preferable. Demerec. 4. Allelomorphs or suspected allelomorphs of h such as marbled, stippled, navajo, mottled, etc., and allelomorphs of R affect- ing plant characters. Stabler. 5. Multiple recessive combinations of genes in the pr-Vg group. Rhoades. 6. Any recessive gene in the gi^ v^ group that is carrying dominant yellow endosperm. Hayes. 7. The combinations al-Y-Pl; i^-ra-gl ; *nai 1gq-g1c»-'b; pr-bm^ su-gl^; Y-Pl pr-bm-^ P-f^-an; p-f1-an. Burnham. 48 8. Multiple seedling combinations for the same and different linkage groups; particularly new genes such as lg0, flossies, argostripe. Randolph. 9. The combination a^ pr in with any glossy. Randolph. 10. Seedling genes in the Y-Pl group other than al and py. Randolph. Recommendations concerning symbols for nev/ characters: Since approximately 290 different characters in maize have been described and assigned symbols it is becoming nore and more difficult to find appropriate symbols, suggestive of the charac- ter, for new genes. Therefore, we recommend the following: When a new character arises which is similar in its appear ance to a previously described character it should be given the same symbol as that used for the old character except that the subscript, of course, shall be different. This has been done in the past, e.g. the different virescents, glossy seedlings, etc., but it has not been followed in all cases. As a concrete example of what we have in mind, we have different striped leaves des- cribed as fine streaked, fine striped, green striped, yellow striped, japonica, iojap, striate, etc. The number of geneti- cally different striped characters will probably be great. Therefore, instead of trying to find a new symbol for a new strip designate it as jg if it resembles japonica, or ysg if it re- sembles yellow stripe, etc. The sane holds for the male steriles dwarfs, etc. Unless we are willing to do this we shall be forced to use tri-literal symbols, or bi-literal symbols which in no way suggest the appearance of the character. be strongly urge tint you correspond with this office be- fore assigning symbols to nev; characters. We shall keep the list of assigned symbols up to date so that we can be of assistance in assigning the proper symbols. The success of this project depenas entirely upon your cooperation. There have been several instances in the past where tne same symbol has been used for different genes. This is confusing not only to maize geneticists but to others. Listed below are tne best available multiple combing.tions of genes in each of the 10 chromosomes: Some of these stocks have just been isolated and the supply of seed is limited. By next summer enough seed should be available for everybody having a legitimate use for the stocks. However an attempt will ba made this spring to supply any of the listed stocks as long as the supply holds out. 49 M a p d i s t a n c e Total l e n g t h c o v e r e d by of k n o w n Chromosome C o m b i n a t i o n these f a c t o r s g e n e t i c n an I p - b r - f -bin 1 8 5 ± 125 ± 1 2 II l g r gl e -b- v 4 SO ± 80 ± III a ^ - n a - c r ^ 79 ± 79 ± IV su-Tu-gl,, 40 ± 70 db V ys-pr-brn^ 50 ± pr-bnr -v 57 ± 1 2 VI a l - y - P l - p y 69 ± 69 ± VII B n - g l r v 5 26 ± B n - r a - V p 26 ± b VIII j -ms8 27 ± IX yg - c - s h - w x 52 ± 96 ± X r-g-nl 33 ± 33 ± arovization technique: At -the bixth International Congress of Genetics, Professor Vavilov reported Lyssenko’s discovery by which the growing period of plants can be appreciably shortened (jarovization). If the claims of the workers investigating this problem are justified, this discovery is of great importance to riant geneticists and to plant breeders. Following is the description of the method ’worked out for maize and described in the Bulletin of Jarovization, 283: 105- 108, 1932, (1) Add water to increase the water content of the seed to 30 per cent of weight. (2) Keep the seed in aarkness for 10 to 15 days at a tem- perature of 20 to 30 centigrade and allow it to germinate. By regulating moisture the germination process should be controlled so that the germ does not aevelop excessively. 50 -H z> co +1 o CV2 Tho following stocks have bean received: Brink - (l) lg1-ts1-v4 x lg1-Ts1-v4; (2) o±-lg2y (5) p-br-f-bmg; (4) g^-fi-v^ (5) glg-ts1-v4 x gl2-TS;L-v4. Sprague - (l) r-g-nl; (s) B PI su; (3) al-y-Pl; , xaRfe (4) Bn-gl.-v ; (5) Pc-, Pc? Pc3 pc4 - Pc = purpl U , ^ ^ _ coleanoT*rVhiiiza (6) bt bt0; (7) AGR so so, so = oran.' e scutellum; (8) sy sy - sy = yellow scutellum; (9) Sx - scutellum color; (10) gl ; (11) glg; (is) gl ; (13) gl ; (14) gls; (13) gl^ (16) gl8; (I7).glg. Beadle - (l) sr; (2) gs (early); (5) su-Tu-gl . Demerec - (l) xug; (2) w^; (3) p (4) pg4; (5) pg5; (6) pbx; (7) pbg and pb5 (duplicate factors); (8) pb4; (9) zebra1; (10) zebrag; (11) zebra5. Stadler - (l) Y a Rg C pr in b pi; (2) a r C pr wx y; (3) Pvv A Rg c sh wx pr su; (4 ) A C r& sh wx y pr Su su - rg derived by , x , mutation from Rg; (5) a C rt6 pr in y wx Su su. Jenkins - (l) C C R R pr pr ag a^ (Bt bt); (2) gl1 ij YY; (3) gl4 v5; (4) gl ij YY seg. frx and frg. Eyster - (l) g^; (2 ) g4; (a) pk; (**) 1 0 ; (5) (Gj (7) f3; (8) sug; (9) yt; (10) da; (11) ar; (12) sa (13) aux; (14) aug; (15) oy; (16) ms2; (17) ms5; (18) vp1; (19) lis18; (20) crg; (21) ns20; (22) bt4; (23) pgg. 51 ivlangelsdorf writ os that he can furnish the folio- ing late stocks; (1) B b na na; (2) na g; (5) g; (4) Y y PI pi; (5) lg gl ra; (6) Pr Pr RR cc v-x v/x; (7) £ b lg lg Sk sk; (8) pr pr RR CC su su; (9) Tu tu su su; (10) Tu tu Ts^ tSg su su. K slip ton advises that he can furnish: (1) ra g li lg; (g) ra g lg br; (3 ) pr li lg f; (4) cr 11 gi - gl = gigas; (5) lg ad f; (6) vx lg gl. Lindstrom can furnish: (1) r g li b pi; (2) R g li b pi; (3) r g nl b pi; (4) R g nl b pi. Singleton and Jones have the following multiple taster: A c R l g g P S u y . Anderson has seed of: P-br-f-bin ; various combinations of sm and sk. be have not listed any stocks from Cornell In the corn letter of October 5. 1932. re listed the multiple testers ivai1a b1e her 3. Appended herewith is the list of maize characters 'with their gene symbols, be have attempted to make this list cs accurate and up to date as possible but mistakes and discrepancies are bound to occur. V/e will appreciate it if you rill call any of these errors to our attention. We are making an attempt to collect seed of all of the maize characters in the central repository at Cornell. In the list of genes re have noted the stocks of which re have seed. If any one has seed of a character listed as not on hand at Cor- n-11, he should send us a small supply of such seed. 52 Chrom- Seed at Gone Character affected osome Cornell Described a , etc. plant, aleurone and III t Emerson f18, i pericarp color Emerson & An derson ’32 plant and aleurone V t J enkins 132 a2 color ad^ adherent tassel I t Kempton f20 ad fi n t Eyster 2 ad3 ft t? t Eyster al albescent VI t Phipps an^ anther ear I ft Emerson ?22 ar argentea IX h Eyster ? argostripe VII t Eyster as asynapsis I ti Beadle and UcClintock au-ĵ aura a IX t Eyster 129 au2 aurea ji Eyster 129 B plant color booster II t Emerson f22 ba barren stalk III t Hofneyr 1 bag f ! II ft Hofneyr bd branched sterile Collins and Kempton be branched ear it Bryan Bh blotched aleurone VI t Emerson 9 branched silkless t Kempton bk brittle stalk ti Vi grans bi1 blotchec leaf t Emerson '23 it u t bl2 Vtiggans bai brovn midrib V t Eyster ’26 ft t 0U2 I t Burnham bn ft t t Burnham 53 brown aleurone V II ff Kyakan T 24 bp brown pericarp IX ft Meyers '27 br brachytic I f? Kempton '20 bs barren sterile vVoodv'orth ’26 brittle endosperm V ft b t i hangelsdorf f26 ?f rt ff bt2 iprcgue bt, tf H - Beadle t-J bt, rt it4 ft Eyster bv brevis V ff Li c aleurone IX ft East & Hayes cb chloroblotch V Ch chocolate pericarp t! Emerson and .mderson ’31 crinkly rt c r i I I I Emerson r21 cr ft IX 2 Eyster ’32 dwarf I I I trdi Emerson ’12 uwarf d2 - Suttle dwarf tt d3 IX Demerec ’23 d4 dwarf d5 dwarf I I ft Perry dv-arf d6 V Eyster ’32 d a dilute aleurone IX ft Eyster ’32 de defective endosperm 1 IV Hengelsdorf ’26 do ft ff ~2 Mangelsdorf ’26 de rt tf ô mengelsdorf ’26 i? rt de4 mangelsdorf ’26 d° ft ?! 5 Mangelsdorf ’26 ff ft d96 Mangelsdorf ’26 de ft ff 7 mangelsdorf ’26 54 1—1 CJ PQ defective endosperm de8 Mangelsdorf '26 de9 fl it Mangelsdorf ’26 it t de10 Mangelsdorf !26 tf t dell Mangelsdorf !26 it t dS12 Mangelsdorf f26 t n de15 Mangelsdorf '26 ft t de14 Mangelsdorf f26 t t de15 IX Brink 127 t i IV de!6 Wentz f25 fi it depl Mangelsdorf ’26 df flint defective X dt dotted leaf ft Emerson fine striped d I ft Lindstron ’18 i t V - f2 Eyster '26 ti fi ft f3 X Eyster fi fine streaked VI ‘ anderson f22 fl floury endosperm II ft Hayes & East ’ll fr frayed VII If Jenkins & Pope 1 frayed fr2 VII If Jenkins & Pope f s fasciated - Collins & Kempto golden X flgl Emerson !12 golden ft g2 Jenkins '26 golden I ffS3 Eyster golden g4 IX ft Eyster Ga pollen tube growth IV fl Mangelsdorf and factor Jones '26 gc glucostactous Eyster f24 gSl premature germination Mangelsdorf f26 ge2 it ft Mangelsdorf '26 55 ge3 premature germination d a n g e ls c io r f ? 26 ft t! ge4 M ange ls d o r f ’ 26 ft ff M a ng e ls d o r f T 26 ge5 gi gigas Kem pton glossy V I I ft Kvakan gll ’ 24 glp glossy I I ff Hayes k Brev/- b a ke r '28 gl3 glossy IV ft Hayes & B re w - b a ke r T 28 g-^4 glossy IX ft Sp ra g ue glossy - It gl5 Sp ra g ue glossy - - gl6 Sp ra g ue glossy - ff Sp ra g ue glossy - ff Sp ra g ue g la gl9 glossy - If Sp ra g ue germless gr-l Demerec ’ 22 geri.il ess gra2 X Demerec ’ 26 gn3 germless germless gm4 V I *gme germless IX E y s t e r ’ 29 gs green striped I ft Em e rso n ’ 12 h soft starch mumm ’ 29 hs hairy sheath ft Ta v c a r I inhibitor of aleurone IX ff E a s t 6c I la y e s ’ l l color i j iojap V I I ft J e n k in s ’ 24 in intensifier of V I I ff F r a s e r ’ 24 aleurone color * reported as gin . 56 r> i—i j j aponica VIII tf Emerson ’12 Kn knotted leaf ff Bryan luteus X ff d Lindstron ’17 luteus X ff Lindstrom T25 12 luteus - - X3 Jenkins & Bell luteus X - Jenkins & Bell 4 luteus V J! Eyster ’32 luteus IX ff Eyster d luteus IX ff Eyster la lazy t! J enkins liguleless lgl II ff Emerson ’12 liguleless lg2 III ft Brink li lineate X tf Collins and Kempton ’20 lp pollen lethal V ff Rhoades rn yellow white seedling Stroman ’24 1 n if tt U2 Stroman ’24 me micropyle color Singleton and Jones mb mid cob color Demerec 127 mg miniature germ Wentz ’24 mi midget plant Perry mr midrib Kvakan ms^ male sterile VI ff Singleton a-nd Jones ! ff ff aS2 IX Eyster tf It mS3 III ft Eyster LIS. M ft 4 Beadle ms_ ff ff D Beadle 57 i—1 1—l male sterile Beadle mS6 ms^ tt tt Beadle mse tt tt VIII Beadle ms9 rf tt Beadle tt tt Beadle tt tt Beadle nsn ms. o tt tt Beadlel/C tt tt Beadle mS13 tt tt Beadle aS14 tt tt Beadle mS15 tt tt Beadle ms16 tt »t I f t Emerson ns17 tt tt V ft Eyster ms18 it tt Eyster ms19 - ms ^ ft tt IX ft Eyster20 Mt mottled aleurone X ft Kempton *19 na^ nana III tt Hutchinson »22 nana Perry na2 nl narrow leaf X tt Emerson opaque endosperm Singleton and °i Jones 0 tt tt Singleton and 2 Jones oy oil yellow V ft Eyster *32 P, etc. pericarp color (memy I If allelomorphs) piebald If Demerec *26 pbi pt>g piebald f! Demerec Pb-r piobald ft Demerec piebald t! Demerec Pb4 Pb5 piebald - Demerec 58 o 01i—i 0 coleorhiza color tt Sprague pcl pc it it ft Sprague \ . JV 63 cnI—1 >> MAIZE GENETICS COOPERATION NEWS LETTER u December 18, 1933 Department of Plant Ereeding Cornell University Ithaca, N. Y. 64 N e w Y o r k S t a t e C o l l e g e o f A g r i c u l t u r e a t C o r n e l l U n i v e r s i t y C o r n e l l U n i v e r s i t y A g r i c u l t u r a l E x p e r i m e n t S t a t i o n I T H A C A . N. Y. D E P A R T M E N T O F P L A N T B R E E D I N G November 13, 1953 To Maize Geneticists ij.s v/as the case last year, this laboratory will again attempt to act as a clearing house for information and a distri- buting point lor genetic stocks, This letter is a call for information to be used in succeeding corn letters, be thought it ould be appropriate if the first letter in the fall of each year presented new* and per- tinent information of value to all maize investigators, such as new linkages, revised or corrected linkage maps, new combinations of genes, new allelomorphs, reoccurrences of known mutations, etc. So '/e are, therefore, requesting all maize geneticists to send us any information they deem of value to others. It Is under- stood that any information or data which appear in this series of corn letters can not be cited in publications v-'ithout the direct consent of the contributor. As an example of the kind ol information we would like to have for the first letter, we "•ill give the folio wing unpublished facts: 1. Emerson has a new glossy seedling which is linked with fine-striped-, (f,). Seed avail- able. * 1 ‘ 1 £. Hayes reports that argostripe (ag) is allelomorphic with iojap (ij) and that lazy (la) sho.s linkage with the su-Tu group. 3. Lindstrom has a new recessive sun red plant color. Seed available. ihe above are sample items of a type tha.t ill interest everyone, we ’want more ol them for the first corn letter, we would like to have this letter in your hands before the Christmas meetings at Boston so the dead line for contributions will be Decemoer 15th. Everyone is urged to contribute so that these letters will be of real value. ^nis winter ve hope to make an inventory of all the genetic stocks in maize, ihe stocks * ill be listed under t\:o categories: (l) Combinations of factors belonging to the same linkage group and (c) combinations ox genes belonging to dif- ferent lin^kk;z ge groups. It should be of great help to all inves- tigators to know v/hether a desired combination of genes is al- ready in existence or whether you must spend several years in 65 o /C o building it up. For that reason we ore asking that you go over your genetic material and list the different combinations under the tv jo categories. Care should be taken that the proper sub- script is used for the different glossies, etc. If possible state whether of early or late season, l.e should like to have those lists as soon as possible. Me hope to have the complete list ready for mailing by February is!:/so January 15th is set as the dead line for receipt of this information. You \ ill bo interested in kno: ing that the Drosophila workers have recently decided to start a cooperative group modeled after the one for maize. The following paragraph is taken from the letter calling on the different laboratories to organize: "for several yesrs now workers on genetics of maize have been receiving mimeographed circu- lars prepared in Professor Emerson’s laboratory, containing information contributed by various investigators. This service proved to be so use- ful that steps are being taken to extend it and make it a permanent institution.1. al'e g lad t h a t the 3UCCC3 s of the maize group has s t i n - ula ted the Dr020p h i 1a i n v e s t i g a t o r s to undertake a similar cooperative enterprise end v, e hope they find the- same genorou spirit oi cooperation which you rmize workers have shown. in ememb or we would luce to have the requested information soon as possible Sincorely yours, t T). y> ). h. 66 M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A , N E W Y O R K December 18, VXZ \Xo-t. H To incite geneticists The response to our request for news items has been good. The various contributions which have been received comprise the bul'-: of this letter. .-11 ol the information given in this letter is unpublished and your cooperation has made it x>ssible to place this mass of information in the hands of maise investigators considerably in advance of its publication. e believe you will find this letter interesting and profitable. If its success justifies it v:e plc*n to have a similar nows letter in the fall ol each year so thet the workers in the different laboratories can keep in closer touch. V.hile this corn letter is essentially c list of ncvr infor- mation, we shall be glad to include in subsequent letters lor this year m y facts ’hich you think will bo of interest to others. ■. c wish to emphasise again that the listing of information in these news letters does not constitute publication. The con- sent of the contributor should be obtained if you wish to cite his data in your papers. Hows items from Ithaca: 1. Dwarf, (d.) gives approximately 55 per cent re- C, u, combination \ ith a,. (Singh). а. Dwarf^ (d,p is in linkage group X. Order is (v ingh). 5. Glossy 10 (pI-̂ q ) gives 15 per cent recombination with fine striped^ (f^). (Lmerson). d. Pigmy, (x / r ) belongs in linkage group I. (Lmerson). 5. Japonica, (J_v, ) is about 5 units from Tu. Order & k. unknown at present. (Emerson). б. Two new r allelomorphs. Krg gives with a red plw.nt, red anthers, green silks; r£r gives with u green pl^nt, green anthers, rod silks. (Lmerson). 67 7. r families segregating for in-ra-gl^-Vc give date, which indicate the order is in-Iii-fll1-v5 . (: raser) . 3 c i:vUreco (au-,) lies bet'.;eon wx and y- in linkage group IX. Order is c-sh-v.x-au-, -vn . (Creighton). 9. Yellow-green (ygc.) is about 1 cross over unit from she terminal knob on the short arm of chromosome 9 . (Creighton), 10. argentea (ar) and v^ whose loci fall close together on the genetic map are not allel- omor ph s . (Crei ghton). 11. Brown midrib^ (bin,) is situated in the short arm of chromosome 5 and there is good evi- dence which suggests it lies extremely close to the insertion region. (McClintock). If. L new narrow-loafed character is linked with a-̂ . (McClintock), (as I remember, wlcClintock told me last summer it gave 30 per cent recombination with a^ - Ed.) 13. Data from crossing over in trisomes inaicate that ra and vr lie on opposite sides of the insertion region of chromosome 7. (Rhoades). 14, a dominant modifier interacts with recessive _â to give a speckled or spotted alourone, Interaction with recessive c and r unknown as yet. No difficulty in classification. (Flhoactes) . 15. In addition to the #5 and #7 trisomes, a , #3, and #10 trisomes can be distinguished from their dicomic sibs by morphological differences (Rhoades). 16. There is an extremely high correlation between small seeds and trisomy for chromosomes 5 m d 6. (Rhoades). - Seed is available for all the new characters listed unde the Cornell heading. 68 New; items fron Pam gang: 1. Chromosome 1 is involved in 17, chromosome & involved in CO, chromosome 5 in 22, chromo- some 4 in 18, chromosome 5 in 1C, chromosome 6 in 14, chromosome 7 in 11, chromosome 8 in 11, chromosome 9 in 1C, and chromosome 10 in 16 different reciprocal translocations. Most of these translocations have been ob- tained in a homozygous condition. (Anderson). Note: anderson hi s kindly offered to furnish any of his translocations to anyone who can use thorn as a tool in his research. The com- plete list of these interchanges (reciprocal translocations) will be listed in the next corn letter, anyone desiring in interchange should write to ^ndc-rson and explain his needs to him. A. Chocolate pericarp (Ch), that long elusive gone, seems to belong in chromosome 5. (Anderson). 3. Something wrong with albescent (al). Does not seem to belong in linkage group* VI. (ander- son) , Nu>.s items from New Haven: 1. The c ha.r ac t e r r amo s a (ra) has appeared three times in different inbreds. All wore allelo- norphic with r:^. (Singlcton ind Jonus). A, Mutation of Su to su occurred in one seed out of a total of 127,000. (Singleton and Jones). 3. a. brittle endosperm was found in a flint corn from Germany. Tests showed it to be allelo- morphic with bt1 . In this same flint corn two iaZy (la) plants appeared in the second year. Tests are being made with la.. (Singleton and Jones). -1 A dominant ragged (Kr ) similar to R a occurred in a Laaming Lvergroc n hybrid back crossed twice to Leaning. Is being tested with Pqw . Tentatively called Hr (Singleton and Jones). a now brown mnwrib i ppcw.red in an inbred line of Country Gentleman. Is b a ing tested v:i th the other brown midribs, (Singleton mid 1one s) o 69 6. L viviparous seed-white- seedling combination appeared in an Fg popul: tion. The develop- ment of the character varies. Sometimes the seeds germinate on the ear. If they do not, the. seeds have a pale yellow endosperm in contrast to the normal orange yellow seeds of this strain. Pale yellow seeds always produce white seedlings. Orange seeds pro- duce only^normal green seedlings. (Singleton and Jones). 7. Dull brown blotches (di) appeared in the en- dosperm of one of our y su Country Gentle- :.ian inbrods. This behaves as a recessive character. Dull blotched seeds when planted produce sterile dwarf plants, rbout £ feet high, with no tassel or car. Non-blotched seeds produce normal plants. (Singleton & J.nes) . 6. The linkage relations of the following charac- ters, which segregate sharply, are being studio!; 1 • op;: que-^ (o^) - undo .sperm soft. st. rch, entirely opaque. b. opaquern, (o0) - similar in appearance to o-i . Both give £5 per cent opaque- in Fr,. c. threaded (th) - seedling end plant char- acter. Very fine pin stripes similar to threaded1’ cloth. d , semi-dea r f — X1 pi: nts about £-1, /a foot high. C? . sc ui-dwa rf - pi: nts ab out 2 £-1/ /C feet high. f . I ... r ,0 d ( M . J - r:layd be M r OfT “ I*-- q “ :w y b.a ; lL-1* h . yellow dvarf ('kd) : bout a o per cmnit r< c omb inat ion bet;t ecn Y and■ y d . i o .~ij_ c re pyle color ( \wc; intensi -e r*..;d dot : nicropylo when plants have large P. Tests are. being made to determine .■hethe-r an allelomorph or modifier of p j - addition; 1 tests are being made to de- termine the linkage relations of sjq and l_o with characters in the fourth link- age group other than su. (Singleton and Jones) , 70 9. a much-brinched ear and tassel character was found in a field of corn at Fort Atkin- son,, Wisconsin. Same os ra^. (Burnham). 10. Nov; genes being studied: brown-midrib (ba~) yollov; green (ygr.) green stripe (gso) a mottling allelomorph of r, -and an inhibitor of this mottling. (Burnham), 11. Revision jf linkage group V. The most probable order is Vp-ys-^-pr-bv-bm^ v/ith bt-. very close to bm-j_. V<, lies 'toward the one of the longer arm. ^Burnham) . IS. There is some evidence to indicate that ra is either between r.l̂ and v^ or that the order is fily-Vg-ra. (Burnhaxi). IB. Albescent (al) may not be in chromosome 6. (Burnham) . News from Madison: 1. a new workable character, pale midrib (pm), appears to show 10 to BO per cent cross- ing over with Rr,-. . Seed available. (Brink). ^ S. ii new allelomorph of thu unplaced gone, golden a, is reported. Golden k (jLg) appears to be independent of r . (Brink). a. nu>. ramose (rc.p), less emtreme than but readily classifiable. is reported. Sued ...vail; bio. (Brink;. Nev> s f r jm the U . S . D . a . : 1. Lazy^ (l̂ .j_) shows linkage in Fg with su end flig And in back cross counts with Tu. Appears very close to su since there was only ;ne crossover among several hundred Fg plants. (Jenkins). S. Ag is linked with bt^ v/ith about 7 per cent crossing over. Limited data of a three point backcross indicate the- order is pr- btj-ap. (Jenkins). 71 £. i now iiL.tu.ru plant chlorophyll deficiency, ten- tatively celled gs is in the Sue m d link: go gr dup much closer to B than to lw. (Sprague) . 4. One of the duplicate factors for orange scut- el lum (s_21) is in linkage group IX. The >rdcr is apparently s.^-c-sh-woc. (Sprague) . 5. Glossy 4 (gi4) is in linkage group IX. Gives about 40 per cent recombination with v, and independence* with c and sh. (Sprague;. 6. i.n almost complete linkage was found between light colored seeds and albino seedlings. (Bruns ;ii) . Nous frjm Minnesota: As was stated in the corn letter of November loth, the following facts were reported: 1. i rgostrioc (ajg) is allelomorphic with iojap (i.j) . (Hayes). 4. Lazy, (la,) shows linkc go with the su-Tu group. (Hayes). News items f r ;m Bucmnell: (During the past y^cr Eystcr sent in t; this office the following pieces of unpublished information: 1. a dominant ..luur ;nc diluter (Da ) is 6 units from Cy Order is Da 2--e---v-x. ^ 2. Opaque und^sperm^ ( . ) bcl >ngs to linkage gr >up IX. ° 3 o. Scarred endosperm (sc ) belongs to linkage group IX. d 2 4. Yellow flecked seedling leaves (yf) belongs to linkage group IX. Su&r, gives about 47 per cent recombination with X» 72 This office has already received several lists of genetic t jd z s . The dead line for receipt of lists of these stocks is anuary 15th. We strongly urge thjse of you who have, not ax.do an inventory of your genetic strains to d) s j in the near future s j that the next c.,rn letter nay present an adequate list -jf existing stocks. In the c x.iing c ;rn letter to hope to bo able to present for your criticism a tentative system of nomenclature for naize genetics. 8 inc ercly your s* >/. 7 7 ) . 73, 73 ^ v. MAIZE GENETICS COOPERATION NEWS LETTER $ January 25, 1934- Department of Plant Breeding Cornell University Ithaca, N. Y. 74 N e w Y o r k S t a t e C o l l e g e o f A g r i c u l t u r e a t C o r n e l l U n i v e r s i t y C o r n e l l U n i v e r s i t y A g r i c u l t u r a l E x p e r i m e n t S t a t i o n ITHACA, N. Y. DEPARTMENT OF PLANT BREEDING ir*£. t> January 25, 1934 To maize geneticists :- The inventory of genetic stocks which comprises the bulk of this letter is, of course, not complete but it will serve as a basis for future and more extensive lists. We wish to thank those maize geneticists v/ho have cooperated in making this inventory pos- sible. Its value should be apparent to everyone. In a plant such as maize where it takes several years to build up a required stock for a certain experiment, it is essential that the list of existing stocks be kept up to date and be available so that the investigator can make use of these stocks. No attempt has been made to credit the stocks to different investigators. Those stocks which are marked with an asterisk are those which have not been received here at Cornell. It by no means follows that those stocks which are not marked by an asterisk were synthesized here at Ithaca. In the past we have received so many stocks from different cooperators that an attempt to trace the ori- gin of the different stocks seemed a hopeless task. So we have purposely avoided listing the origin of any of the stocks. This does not give the credit due those investigators who have spent a great deal of time in building up good genetic strains. In the future we shall try to remedy this condition. In order that this laboratory may serve efficiently as a dis- tributing center for genetic strains, we urge those of you who have the stocks marked by an asterisk to send a small amount of seed to us so that it can be increased for distribution. ^t the Boston meetings a system of nomenclature was agreed upon by representatives of the Drosophila and maize groups. This proposed system, as it applies to maize, is submitted in this report for your consideration and your criticisms and suggestions arc re- quested. It was agreed that the needs and requirements of maize and Drosophila genetics were so diverse that it would be unwise to attempt to formulate an identical system of nomenclature. Yet in the matter of symbolizing genes, designating translocations, defi- ciencies, etc., it was felt that a uniform system could be employed with advantage, end the symbols which arc- used in the proposed sys- tem were agreed upon by the representatives of the two groups. It should be clearly understood tnat the proposed system is only tentative. It can and will be modified in any way that will make for a better ana more useful system. 75 The proposed nomencl&torial system for maize is as follows* 1 , The linkage groups will be designated by Arabic numerals. Group 1 will include those genes which lie in the longest of the monoploid set of 10 chromosomes, etc. The longest chromosome will be called chromosome 1 and the shortest chromosome 10. Arabic numerals will be used for both linkage groups and chromosomes since the Roman numerals arc too cumbersome. 2. Whenever biliteral symbols are used the second letter shall not be dropped as a subscript. Italicize gene symbols. 5. Literal superscripts shall be used to represent different members of an allelomorphic series, e.g., Rr, R&, rr, r£. 4. Numeral subscripts shall be used to represent different genes which give phenotypically similar effects, e.g., 1 1 , 12, 12, etc. 5. The normal allelomorph of a mutant gene shall be designated by the use of the + sign as a superscript, e.g., the normal allelomorph of sugary (su) will be su+, end not Su or + . The plus sign alone may be used for normal allelomorphs in such genotypic formulae as > but these allelomorphs should be designated as indicated above when the formula is written as su* Tu* / su Tu. This suggestion was made by the Drosophila group and we believe it meritorious. It enables one to tell whether the mutant gene is dominant or recessive to the normal or aver- age condition. And, too, the normal gene is nothing more than an allelomorph of the mutant one. 6. The letter T (italicized) shall denote reciprocal translo- cations or segmental interchanges. T(l-£)^ would represent the first case of a reciprocal translocation between chro- mosomes 1 and 2, 1(1-2) 2 the second, etc. Numeral subscripts instead of literal ones are recommended to denote the differ- ent translocations. There are several objections for using a, b, c, etc. to denote the different translocations. Then more than 26 different translocations involving the same two chromosomes are found we should be forced to use biliteral subscripts, such as aa, ab, ac, etc. The letters of the alphabet have in the past been used for symbolizing genes. For example, we have designated the different virescents as Vi, vg, 2LZ> etc., and not as vr, vg, vc, etc. 7. The symbol Df (italicized) shall bo used for Deficiency. For example, the first deficiency involving chromosome 10 will be represented as Df IOqj the second as Df lOg, etc. 8. The symbol In (italicized) shall stand for Inversion. An inversion involving chromosome 4 will be represented as In 4-̂ ; the second one as In 4g, etc. 76 on • 9. It was decided that there was, as yet, no need to formu- late a system of nomenclature for duplications. This office will do all that it can to enable you to secure any of the stocks listed in this letter but it should be remembered that in several cases the amount of seed is small and we may not be able to fill your request. Sincerely yours. " h 7. 7r?, Jj u a s 8. MMR: B M. M. Rhoades ENCLOSURES 77 i. P br fi bm2 p + + an bmg13. p br f-u + bmg ^ 2. p br fj baig p 14. p . b..r.. f. ij - adix + p 3. £ br f1 bnig p br fj + bmg 2 4» P an bmg p br f-,X . .a. n +15. p p br fL + gsz z 5. p ad-: bmr. p + + + bmg 6. P 6l10 ?! + 16. p tSg br an + 7. p br fp ad^ * p 8. p br ad-, * 17. gl10 fl an p p + + an 9. an may seg. bm0 * p br f, + an __ 1 p 10. p fjL bmg * 18. p br ad-j + 21 11. ts0 f1 may seg. bmg * p tSg or f ■f’ an IS. tsp an may seg. f, bm * 19. p + br f1 ad̂ _ + 20. p sr oooooo Linkage sroun 2 1. lg]_ glg b V4 8. gl2 x ^2 2. lgx gig b v4 seg. tsx * 9. glg v4 seg. ts1 * 3. fl v4 * 10. gi2 fl v_ * 4 4. lg1 B v4 11. gl2 fl 5* lgj_ b v4 12. v4 seg. ts1 *lgl 6. lg B ba seg. . b sk v. 1 2 1 3 lgx 4 7. lg1 b ba? seg. 14. B sk 15. lg^ B seg. ts^ 78 1 . ar -na~ts4 10 . a? d - ^ - c r 2 . ar - t s 4 11 . lg,p~d-^ na +ai 12. t - i - i g go . + + c r 13 . &xi - c r * 4 . a i + d ^ c r + Rg + + 14 . a1 -R g * 5 . - n a - c rai ' 15 . al - ^ ai 6 . ar - n a - t s 4 16 . o r r ms3 c r + 7 . • Fp * 17 . Pgp-d-j seg. + pgo Cj a ts. 18. 4 "1 4 + + F28. F+ + cr 9. ar -na-ts^-cr 19. ai Q2 oooooo Linkage group 4 1 . su TU gig 9 . SU T s 5 + F Pft 2 . su +g l 5 + 3 . su Tu 1 0 . su h 4 . su T 1 1 . SuxsS5 h su TSc; + 1 2 . su s t * 5. , 5 T?y + V/i * ^p 1 3 . su Tu T s r * 6 . su Tu + _ + -------------- Fo+ val 2 1 4 . seg. su and vp_ 1 2 o su g i , + 1 5 . su l a * 7 . 3 F „ -I- + w l 2 1 6 . Tu l a * + 8 . su T u + F „ 1 7 . su 1 8 . su l o + + j g 2 + lo + + 1 9 . su -S£ ++ + 2 0 . +su sp 79 o , 1. pr vg 10. bt^ bm^ * 2. pr vg 11. ys1 pr bm1 * 3. v£ pr bm^ 12. ys^ pr bm-j s 4. pr bm^ IS. pr vlp bm-̂ * 5. ys1 pr bt 14. pr v3 bun * 6. a?-bt1-pr 15. ys pr v*o * 7. vg ysx pr * 16. v -bv 2 8. pr bv bm^ * 17. pr vl£ 9. vc pr bv * oooooo ■LT-i".n —kage^ £roun G~x 1. y PI py 9. Y Bh PI 2 . y pi py 10. y pi sm 3. y pi py 11. y-si-pl seg. 4. y PI py 12. v?-y-pl 5. po y pi * 15. v?-Y-pl 6. po Y pi * 14. v b-Y-pl 7. po y pi * 15. Vg-Yy-pl 8. 3m Py py © * Stocks carrying al are not listed since there is considerable doubt that al belongs in this linkage group. oooooo 80 L:w; :.. ̂ e Group 7 1. bn d i vb 9. ra si <6 // 0 Bn fill v5 10. Bn gli si m<_y 9 13 ser. frn and l‘r 1 2 11. bn gii sl 4. ra-gix--VeD 12. \ T r' -4S* gll v5 V“1 5. ra v5 13. in gli Vr5 <3 p> 6. Bn ra * 14. in ij + ra 7. T. Fp * 15. in gin gii + ij 2 X 16. gli ij 8. Wh gl-jX 17. si ra oooooo Linkage group 6 1. j__+_ + ias0 FS ocoooo 81 l. ySo c sh 11. sh ar k, e sh wx v1 lc- » cvU-i uUr; 5 . c sh v15 wx IS. c sh v;x d,_ seg o 4. j.RC wx. homozygous ter 14. ygg sh d seg. rainal xnob on 9 * 15. sh lc 5. c sh bp \*• \ij--r -?! o 16. sh-wx-w.^ Fg 6. ar P-k sh "ic* c sh wx au x 7. e sh wx C sh Vvx au- 8. da1 LU1 au2 sh 18. da au-̂ sh 9. c sh V;X W11 seg 19. I sh 10. sh mSJ> oooooo Linkage Group 10 1. r gx PE]_ g]_ r seg. tc'j. r gx nlx 8' pgl 12 se£> 3. H gx nl^ S' gl X4 SC"£‘ 4. h g-ĵ 10. d7 r g-L seg. 5. li 11. r tester stock which does not carry the inhibitor of 6. 12 r gl seS* the mottling allelomorph. 12. g-̂ -r mottled oooooo 82 Multiple combinations involving tw-o or more groups Ax C-sh-wx r-g Pr £■'1 rr C E-lg Y-pl pr j a C-sh-wx r-g pr R C lg y pr j in Su C-sh-wx R-g Pr Gi R wx Bb-lg Y-pi pr su Ax C-sh-wx R-g pr sh-wx B- £i R lg Yy--PI Pr C-sh-wx R-g-nl Pr s _ i R£ pr Y in b pl * 3-lg Y-Pl su-Tu -6 pr In Su su v_Pi 1 p1 bu2 3 may seg * A 3-lg Y-Pl Su-Tu tSo d,1 A1 B-lg y-Pl Su-Tu pr p i ~\T 6 1 5 B-lg y-Pl su-Tu pr lg in A-, B-lg y-Pl su-Tu-+ lg crl -V 7^ + ”+ y-+ su^+-gl3 1 ° 1 5 pr BB-Lg lg Su-tu Yy-Pl pi wx * in~£ll pr in-ij Bb-lg Su su-tu Yy-Pl pi wx * pr-•bm^ an BB-Lg lg su-Tu tu Yy-pl hx wx * pr fr (Br i Bb-Lg lg su-Tu tu Yy-pl V.x wx * pr iG-gig b-Lg lg su-tu y-pl wx * 2 or ts4 * a^ pr in wx y C R& Su su pr a.-nr- ax E PI C R Pr Y pr-•bm^ su A^-cr C Rg pr su y-pl b-lg j pr- U1 3-lg Y-•PI Pr C R bmi y r* pr g ^ - r a "*1 B-lg y--pi Pr R S sh-wx h B Y-pi Pr C R Su 1 » _ V.rn v/x !'V-cr C o rr_g pr in 1 Su su y-pi b-lg sh-wx su :auy seg« tSg d-L j - R m l *-bm TT A Cc Rf' pr In in Su su y-pl 3 v;'x b-lg bmg j v? may seg. wx *;r ygi «1 dx cr tsg ;h-wx pr- A^ RB c-Sh sh-wx pr in su y Pvv ih-wx- 83 >i—1 Xg-glo-’o wx Fg » A B p1 lg tsx Fo 1.C R ar ts4 lg gig Fg b pi pr v9* aj-na-ts^ C-R B PI Fg * A C R pr-bm^ v/x may seg. v bmc cr * n C R lg-3-v4 pr bv Yy-pl F0A/ A C r brn,. *̂̂ 1 ^1 j Y Ch i su * a_-na-cr Y-pl gl-j-Vg SU-gl3 lgx-v4 * ci -j —nc<. —cr Y-pl b-lg gl-^v- a. 3 PI c-sh-wx pr su-gl * a. i“na b-lg Y-pl 1 O a B PI c-sh-wx Pv su-Tu * a. 1—na—cr b-lg Y-pl A c R pr lg-j_ g1 Su y Bn a-,-Na nr-Ts4 ts4 b-lg gx br-li seg. bd (branched silkless) a-̂ —na b-lg Y-pl gl1-v5 g -li wx seg. bd. A C R Pr gl^-ra * cr li gi a C R so, sc>1 2 ra gj-li lg na Hr-g^ B Pi su a B PI li lg]_ fx • #& trisome fi % gl fl #3 lgj_ i #5 ! rax gx lg1 br #6 n V/X lg1 gl-ĵ #7 li cr ra^ f #8 t. a r C pr wx y Bn ? * #9 ?; a, C r pr wx y Bn ? #10 n C R& pr in y wx Su su A C (Rr)? Pr (Bb)? pi Yy tetraploid AC rS sh wx y pr Su su A C r& b pi y Su tetraploid a C pr Y pi in b a-j C R pr y Su A C R pr su Tu tu gl A2 c R Pr y Su P sh-wx su lg-b f A^ C r pr y su * &2 P sh-wx Su lg-b C R pr y 84 Ax C R pr sh hx b pi i^i y A o R sh wx b pi y Three- inbred strains of Leaning selfed for 29 years. * Strain resistant to physiological forms 1 and 3 of Puccinia sorghi. Strain susceptible to physiological forms 1 and 5 of p. sorghi. Strain resistant to physiological form 1 but susceptible to physi- ological form 5 of P. sorghi. List of reciprocal translocations at Cal. Tech. Pedigree Chromosomes No. involved A 11 1- 7 A 12 1- 3 A 13 4- 9 A 14 4- 5 A 15 3-10 A 16 8-10 A 17 2- 7 A 18 3-10 A 19 Cj *7Zj — %j A 20 5-10 A 21 5- 8 .h. 22 8-10 A 23 6-10 24 1- 5 A 25 2- 7 A 26 3-10 A 27 3- 7 A 28 3- 5 A 29 1- 2 30 5- 6 i 31 3- 9 A 32 1- 5 A 53 2- 6 A 35 1- 9 A 36 4- 6 A 37 4- 6 A 38 3- 8 A 40 1- 5 A 41 2- 6 A 42 2- 4 A 43 1- 9 85 Pedigree Chromosomes No. involved A 52 5— i» a 58 1- 3 A 61 4-10 A 62 8-10 a 64 1-10 a 66 4- 5 A 69 2- 7 A 70 4- 6 a 73 1- 7 A 74 1- 3 a 75 8- 5 a 76 8- 9 a 77 1- 9 a 78 2- 8 a 79 4- 9 a 80 2- 6 a 83 8- 9 A 84 8-10 a 85 4-•10 A 87 1-• 3 A 38 2- 4 A 90 2- O a 94 9-10 AlOl cr>,— 4 ,-103 — 7 a 1 1 1 6- 8 A118 A — 3 ,.119 6- 9 a 122 1- 4 a 1£9 2- 4 a 133 3-10 ,-.136 •cV — rf? A137 4— 7 c & , i 125 <0— 6 A & c 6452 5- 6 A & c 6460 o 9 A & c 6462 4- 5 rv & c 6465 o 9 A & c 6466 1-10 A & c 6467 4- 8 A & c 6468 3- 5 A & c 6470 6- 9 A & c 3471 2- 6 A & c 6472 4- 5 A & c 6475 2-10 A & c 6474 3- 7 A & c 6475 5- 7 A & c 6477 3- 8 86 MAIZE GENETICS COOPERATION NEWS LETTER 6 February 21, 1934- Department of Plant Ereeding Cornell University Ithaca, N. Y. 87 784 a S T A T E C O L L E G E O F A G R I C U L T U R E A T C O R N E L L U N I V E R S I T Y NEW Y °o T n E L L U N I V E R S I T Y A G R I C U L T U R A L E X P E R I M E N T S T A T I O N I T H A C A . N . Y . D E P A R T M E N T O F P L A N T B R E E D I N G ( Co February 21, 1924 To Maize Geneticists : Thf- proposed nomenclatorial syste , m1 ft o- r oo iin m si ri a a iz e cra n e h b ul ue - a i sn di n p re on vd o ked scu.. we have ^ r eceivJ ee dn l cci on ms m ens tt sa d «l ne dr , n uM ggu en .g ,o lsdorf, _ sS ffi JeS*S S i s. L sd ar . wi~ t?c a . S« . S^ ; n £ the I cri . . rl S “ r“ « tic .ism .s o .r comments made about each item. rteo 1 - (see proposed nomenclatorial system in corn letter of * J* anu- ary 25th) . Pnn’ticntf" This seemed to be generally acccptaoic to y ̂ crj end chromosomcstexccptfwhcres0thorsusrge ^ i n ? o £ J sfecll? s^ clsrlt'^caA not be obtained by’ using Arabic numerals throughou » te ^ar ae d should be, In those- e x c e p t c h ^ m o s o m S s f f t f Z ^ s ^ / i ^ o f ^ b l c n fa uc mto err ail ly s wme ie llt a sall t isre -quirements and it se s et ma st em toe n ut, - ^a Ds - sm t ad te u bin . the corn letter, shoulu stand. Ttoe fe - Whenever biliteral symbols are used n ot t heb o sd er coo np dp ed l etas t era ss hub as lc lr ipt. Italicize gone symbols. Comments: Sc.tisfuctory to everyone. Item 3 - Litoral superscripts shall be used t - o- - r- e~ p rm ee sm eb ne tr s d io ff f eu ri e na tl lelomorphic series, e.g. hy, fan? £— > 1— • Comments: Satisfactory to e /cryone. Item 4 - Numeral subscripts shall b - e- - u- s- e dg e tn oe s r ew ph ri ec sh e ng ti v de i fp fh eo rn eo n t typically similar effect.,, e.g. l±, v^, V3, etc. Comments: O.K. but anderson suggests it di ms ip ge hn ts e b ow i wt eh l la l tl o subscripts and raise the numeral to oh c cs t s,h e rest of the symbol. rv • i ~ -i-vi-i c: ai7t s cay t s it oe nm d^drop p sl en eg m^ st h p^ oon du u we er a bl els ih es v eS u tb hs c-c tr i tp ht es ph ra es s eb ne tcome widel a yn d u si es d satisfactory so that any benefits th r ia ci hs i mn ig g ht th e n “ u «m ce rr «a fl * to “ the same level as the rost of 88 t of sufficient value to justify the change. ■Therefore we suggest that Item 4 remain as stated. nril 5 - (see proposed nouenclatorial system in corn letter of 5 Janua -r y f th) . Comments: This suggestion has net with , s„ ut c1r hi n wit dh eat s prwe e aw di t oh bd -raw it and belie e vC e,£ ? tn‘ hf ai tn ? t hn eo rm o. l' d]. s; yl sl tc el mo u lo or rp hs should d bf e c^ onn t io nf u c ea dp ,i t ia .l e . l te ht at te r es i tb hee . used a (* e .gi n . rn Han hs S uo ,f Lall cl r S u fs ou r a tn hd e l nr. o) r - m alS omoi pn*> ̂ prague andb e J eu ns ice id n st o m ad de es i tg hn ea t ie n uth re e sd oo mina o nf teloaorph rather than the normal allel w oo mu ol rd p ht el sl i ncat e a s ug cl h an ac e p rw oh ce et dh ue rr e the cross was nade in c r oe up pu ll is ni go n orph ase. _6 - (see letter of January 2bth) . Comments: This was acceptable to all save wi ,s .h ne ds e rst oo n ,u s we h oT 1-fa, T 1-fcb, etc., in place oi i U - d p i r Utc He meets the objection that Cw th h^ e t u sw ei ll o f n te hc ee s ls ei tt ta et re s t oh ie tu hs oe to 1f - bi v li il tl o^ rb ae lV so n be y t si tm ae t ib ne gf ̂ o tr ie n tw ̂ e i th ave m ' od ri ev i tn hg a nt h 2e 6' s ta rn ae n st lw oo c ac th ir oo nm so so inm -e s ra .n He fn u- rthet rh es oe bs j eca tn sd s toe es t hen o usn ee ed o f for J io tn ae ls i) c. iziB nu gt tt hh ee lq ou oe ts et ri o Tn Uof s w dh oe ct -h er o p rr e nf oe tr ab Al ne d ei rs s om ne a sn i ^n g sl tee .s ..s 1n ow sinc L e hh ea s h al si s at e pd a pa el rl ik nn o pw rn e st sr a in ns l vo bc fa ct wi ons and has design 1 ated themT j>-fca, etc. Therefore it seems best that v:e a mg or de ie f yw it thh e An pd re opr os so en d' s syt se tr em mi no tl o ogy. S r ia ni cs ee d st oo m e it oa bl ji ec ci tz ii on ng hat she l ee et nt er T we suggest that it sho.l i l ta nl oi tc i tz oe d. Stadler states that he sees n n oot rb ee a su os ne d w hf yo r t ha en y s yk mi bn od l o Tf or c t a r na nslocat p ir oo n,g re iss . .e.i ve simp“ le e ,s e re e cn io p ra o cp ar li ori reason v.hy his suggest w io or nk ab il se . not r Item 7 - The symbol Df (italicized) sh T ao lr l e bx ea m up sl ee, d ft oh re Df ei fr is ct i ed ne cf yi .ciency inv w oi ll vl i nb ge cr he rp or me os se on mt ee d 1 0a s Df lC^; the second os Df 10g, etc. Comments: Generally satisfactory p ar le tf he or u gD hf A1 n0 da e ri sn o np l wa oc ue l dof Df 10^. However Stadler stc.tos th w ai tl l *have a good many defi r cienc it eh se ic nr vp oh ln vb ie nt g w ^o ul sd i ngs lo eo n be outstr D if p 30 p l eo dT aa nn dd sf ii nn cd es Si tt a ds l. et ri s if sa c Ut oo ir ny, b we suggest that the propose t de a sf yo sr deficiencies stand as listed except that the sym n bo ot l b De f i st ha al li lc ized. 89 . , 3 - The symbol In (italicized) shall stand for Inve i rn sv ie or ns .i on Li nn volving chromosome 4 will be represented as In 4^; the second one as In 4^, etc. Comments: Same as for Item 7. Tten 9 _ it was decided that there was, as yet, no need t l o ot fe o ra a u-s ystem of nomenclature for duplications. ifo comment necessary. Vk'C want to strongly emphasize that in t a he attempt tn oo me fn oc rl ma ut lo ar ti ea l system for maize there is no intention of l ei ss th ai bn -g a set, rigid system which can not be modified va r ti oe d f in te ed ts he of a rapidly changing field of rese w a’i rl cl h.a ris -Le — occ ta h*s .i ;ro en s when a modification of the proposed n e sc ye ss ts ea mry isf or clarity v/e do not doubt, out without q g ue en se tr ia ol n r su ol me es of nomenclature which will be followe a dr e w he es nse n pt oi sa sl i. b leT o provide such a general code has been p ou nr ep o os ie s oo hf e these corn letters. We wish to thank t h ha ov se e be oe fn yos uu f wf hi oci ently interested to communicate your views to us. After taking into consideration your comments and w e c rw ii ts ih cit so mss ubmit a revised nomenclatorial sysior: fo h ra s m ab ie ze en wm ho id ci hf ied so as to incorporate some of the changes which were recommended. The modified nomenclatorial system for maize is o.s follows: 1 . The linkage groups and chromosomes will be design n au tm ee dr a bl ys . A raL bi in ck age group 1 will include those genes t h we hil co hng e ls it e c ih nr omosome, etc. The longest chromo 1 somp ei 0 oi od f s te ht e mof o no- will be called chromosome 1 and the shortest chromosome 1 0 . 2. Whenever biliterai symbols are used the second letter b e sd hr ao lp lp e nd o ta s a subscript. Italicize gene symbols. 3. Liter...1 superscripts shall be used to represent different mem o bf e ra sn allelomorphic series, e.g. R£, EEt l£ > r£« 4. Numeral subscripts shall be used to represent dif w fh ei rc eh n tg iv ge e nep sh enotypically si^ilc.r effects, e.g. y^, Vg, y^, etc. 5. The normal allelomorph of a recessive mutant gene n a st he ad l la s b eh a ds e sb ie ge -n customary in the past, i.e. either by o r a b +y sa i gc na pital letter; e.g. the normal allelomor e pi ht h oe fr sS uu co ar n + b, e depending upon which is the most conve u ns ie. e ns T th oe normal allelomorphs of what arc commonly c d oo nm si in da en rt e d genes can ce designated, as in the pa st , b + y s ei ig tn h eo rr by small letters, i.e. the normal allelomorph oi iu can bo either + or tu. 90 91 MAIZE GENETICS COOPERATION NEWS LETTER 7 September 13, 1934- Department of Plant Breeding Cornell University Ithaca, N. Y. 92 M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A . N E W Y O R K • I September 13, 1934 To Maize Geneticists We have the pleasure to announce that the Rock , e+ f-i eo ln lh ea rs Fm oa und -e a grant to support the coopera q t^ in ve er i mo ad i zo ef wf oi rve k y fe oa r rs. We are indebted to Brink l g oe rs te hd a vt io n gt h se u gR -ockefeller people that they aid in a financ t ihe a lc o wo ap ye rative maize genetics enterprise. Last fall we issued for the first time a c i at le lm s fos ru ch n ewas s new linkages, linkage data, s s ho oe rc ti f aic c cop ur no tb sl em os f, new genes, etc. The respons m ea n ai nf de s it ne td e rw ea ss t sufficient to warrant the issuing oi c al al st ih mi is l af ra ll. We would like to have the No dv ie fm fb ee rr e n1 t5 t ih t. e msT h bi ys time limit should make it possibl s ee ed tl oi n og b tc ao iu nn ts this fall before sending in T h ye o ul ri s nt ei wn sg io tf e mn se .w genetic testers is desired so that w t eh e cl ai ns t K eo ef p available maize stocks up to date. In addition to serving as a distributing and b cu or oea pu e rath ti is v e laboratory shall attempt to collect a s nt do c mks a inof t aia nll corn characters. With this purpos p ea st i ns u mm im ne dr , w te m sgr ew 8000 plants in our garde p no sl l ai nn da t oi vo en rs ^w 9e 0r 0e made. Included in this collecti t oe nr s w ew rh ei ch c haha rd a c-not been grown in recent years, a of n db e wi en rg e l io ns t d, a na gs e rw ell as desirable stocks whi p cl he t he ad d t bh er co ou mg eh dca el -ls for seed. The great majority o a xt io tn hs e w pe or le l im na de by Mr. John Shafer, a gra C do ur an te el l s. t udW eh ni ^l e h eo ru er *p rimary purpose shall be to wh pi rc eh s eh ra vv ee tp hr ee ^v gi eo nu es ^l y been isolated, we hope l i tm oi t pe rd o dm ua cn en ,e r m a t a least, some desirable multiple combinations. Since January, 1934 this laboratory has distribu q tu ee ds t ono v re er -350 stocks to different investigators. Through the kindness of R. G. v’.iggans we h d ao vz ee n si en cb urr ee dd s a which are fairly early in seas s oi ns t aa nn dt at ro e t vh ee r )s t rr ea -ins of corn smut present at o If t ho au cr a ,g en ue iti nc c et se os mt ee rs are extremely susceptible a ib tl e st eo e msc ro as ds v it sh -em with resistant lines to obt e ar is. n reIn s iso tr ad ne tr tto e o de - termine which of the inbred w se ws ih la ll l p rs oe vn ed bs ea sm tp les of seed of the different inbr st ea dt si o tn os ss eo v et rh aa lt their smut resistance in diff c eo ru en nt tr v pac ra tn s be o f te ts ht ee d. Those inbreds whic w hi l al r et h me on s tb e r eu ss ie sd t ai nn crosses with the susceptible genetic testers. 93 It is becoming increasingly more important to have lists 0f cytological testers, i.e., strains in which the chromosome morphology is known. Those of you who are engaged in cytogenetic research please go over your material to see if you can furnish cuchinformation and, if so, send us the lists. Pollen classification Anderson sends the following concerning classification of pollen for semi-sterility, etc. uWe cut out some blocks of light redwood, bored holes in them like this and attached handles. Usually we have 96 holes (8 rows of 12;. Ae collect pollen only in the forenoon. No tags are used. Y.e write* the family number on the block and then check the plants collected in the record book, skipping a hole as we pass from one family to the next for safety. The pollen sheds plentifully especially after an hour or more. Tapping the tassel over a slide gives lots of pollen which we look at dry. When pollen is plentiful it is easier to classify dry than in a KI-I preparation. You get used to shriveled pollen after a while so it doesn’t bother much. If it is too shriveled we put on a drop of weak iodine solution. *' Anderson states that his assistant has made as many as oCO classifications in a single day. Le-itz makes a small pocket microscope (Tauschen Mikroskop) which sells for about £14.00. This pocket microscope can be used in classifying pollen in the field. It is a very fast and con- venient method but can be used only when the anthers are shedding pollen. On a quiet morning, however, it is possible to work lor several hours before the pollen has been completely shed. Induced mutants Stadler has kindly furnished this laboratory with the xol- lowing mutants which he obtained in his X-ray work. We increased these stocks this paist summer and they are available for distri- bution to anyone wishing to study their linkage relations. Segregating mutant_________Viability________Linkage indication Argentia (ar_CL) good close to su dwarf (db) good none dwarf (a,.) good slight - Y repulsion o . 94 yellow green (yg&) low none pale green (pga) good close to su (might = ara) virescent (low ratio) probably fair none virescent (v ) good none 3. (not induced) glossy (glb) fair none glossy (glc) fair none fine streaked (f'i,) good none glossy (gld) lethal none pale green possibly viable none pale green very low- close to Y (wilts) pale green lethal LO units from Y The names and symbols given to these mutants are merely for convenient reference, L'hen they have been more thoroughly tested names and symbols will be assigned to them. Maize genetics in the U.S.S.R. American maize geneticists will be glad to learn that an active group of workers in maize genetics is springing up in the U.S.S.R. This work is under the direction of M. I. Hadjinov. have received the- following letters from him which are trans- cribed here for your information. ifYour letter of November 13, 1933 I received only 13th January, 1934. I am enclosing herewith information about our works on the maize genetics. I hope it will be of some value though strongly delayed. During the ̂ last 2-3 years we have carried out this work some results of which will be shortly published. The greater par of them I am sending you today. I should be much obliged if you would kindly send me the mimeographed circulars of the Cornell University on maize genetic and also some genetics stocks. I should like to ask you if you would find it possible to s.ena me also numbers of circulars previously years of which I possess only that of 1930 '’Linkage in Maize*'. I yish to state that I am familiar with the Chromosome Ma m the report of Prof. R. a. Emerson on the VIth Genetic Congress 95 Dr. G. D. Karpetchenko asks me to send his best wishes to you * Yours sincerely3 (Signed) M. I. Hadjinov,'" The enclosure: "Recurrences of known mutations iiguleless. From 7 stocks: Shanghai, Primosky Region (F. East) HTdifferent stocks, Middle Volga region, Armenia, U.S.A. Learning (all tested) and one from the N. Caucasus (non- tested; . ramosa. From 4 stocks: Italy, 2 different stocks of Georgia, N. America (tested). shrunken. From 2 stocks: Middle Asia, North America (varieties Minnesota 23) (tested) . golden^. From West China (tested). green striped. From 2 stocks; Georgia, Learning (non-tested). Teopod. From early sugar varieties (names unknown) supplied by Prof. Larionov; from Ukraine, where Teopod has never been grown before. fine-striped. From 2 stocks: Mexico, N. America (tested). anther ear. From L stocks N. America (non-tested). dwarf.. From 2 stocks (tested). dwarf -z. From 1 stock (tested). barren-sterile. (Prof. Hayes). From Spain (non-tested) barren-stalk. (Prof. Emerson). From Italy (non-tested). tassel seed-j . From 2 stocks. Primorsky Region, N. /-merica (tested). tassel seed.. From 2 stocks. Georgia, Armenia (tested). lazy culm. From Ivory King (N. America) (non-tested). brown midrib. From 2 stocks: Georgia, Sterling (N. America) (non-tested). 4 cases of cvtoplasmatic male sterility: Azerbaijan, Peru, N. Caucasus, America. male sterility. 25 stocks segregated for male sterility are be- ing studied. 96 Now genes R R h ^ Rough sheaths . A dominant gone producing warts in the leaf sheaths in the lower n e pa ar r tt h oe f a tu hr ei c lo el ae. f blT ah di es character a i pn pet ah re i ns gt a ig ne to hf e 7 plt ao n t8 leaves. The vitali i ts y n oo fr m ta hel . plS ae ne td available. vK, rh0. Rough sheaths A rea c_ e_ s_ siw S vi e gene producing the character similar to that of Rh^ Rh . Beside warts this gene causes sometimes a narrowin t gh e ofa pp te he uad ara ln ec ae f bof l adt eh read-like leav p el sa .n t Ti hs e s vo im te aw lh ia tt y l oo iw , t hb eu t in some families norma a lv *a il oa ob ecl ie . glA-gli r Glossy^ -n . 11 different allelomorphs have been recorded from fc5 differen g te n se ts o co kf s .g lo As ms oy n gb y t hi en t 1e 1r crossing and b le ie nn k af go eu n td h eg rl e^ h” a v§ e1 ^ previously described. The linKcige of the remaining genes will be shown below. crg cV Crinkly. A gene similar to crinkly^ but non- allelomorphic with it. Seed available. 5. ygs ygg-yg4 yg4 - Yellov.'-green 5_4 - Duplicate genes. The seedlings are yellow-green till th te h e fl fo lw owe eri rn ing g th se t agy ee ,l lo kw i tp ei vg ment di a ss a pa p es ai rm sp ,l e ir te c se es gs ri ev ge a teg de ,n e in the o i rn ig g iw ni at lh sn to on c- ka .l li Ie nd cf ra om si sl -ies gives 15:1. pla rn ht e i vs i te ax lt ir te ym e ol fy low. Seed available. 6 rs-ir0s.. Ramosa-silkless. This gene c e aa ur ses si m ai l bar r ani cn h ia np gpe i o- fr a tn hc ee to ramosa a b bs ue tn c we i to hf ts hi el k cs. o mplA et t et he same ti t ma es s ie tl , cai un sc er se a n g ino f g cl ums, flowe i rn st ph ie k ep la ei tr s s ap ni dk e al ne tt hs e. r s It gives a n t oa rl mi at ly po of l lt eh ne , pl xa hn ct vi is -normal. Seed available. at at. mtherless. Causes a complet T eh e a bv si et na cl ei t oy f o af n tt hh ee r sp .lant is normal. Seed available. hf hf. Hermaphrodite flowers. * pisti i ln a tt eh e flm oa wl ee r f il so ^w de er v ^b xe os pi ^d ce anthers l go in vg i. n g S ao m se it li km e £s - 6i n cs mt .e ad of a silk m e tn ht ea rr ey ip si st oi nl l. y a Th re u dip -ollen is v e ea rr ys h ra av re e lya dl eo vw elf oe pr et di .l ity T. h e The vitality of plant is normal. vb vb. Variable brachyte. Causes a i n st he ar rn po d sc hs o ru tp e nt io n g1 oc xm . TneT his charac T th ei rs is sh o mr ut ce hn i vn ag r im aa by l e.a ^f fect either i an t ce or nn so id de es r ai bn l ew ha p /f i e n n es F wc 0 1 D v h c ich your. t tpw w i n be testea m l ^i yn sk ta eg .e w •i ith the genes wx and C. I h 5)v a ve these Fg. My ramosa-sili ki/li ensesc ii sc simiJlar to bi*aDr. Kempton. My data, ( ho , lide ned wev t coin ^̂ci d°e wi et rh , t oh no se l io nf a gD er . bK de mpt a on, wh lo o cab te el di ev ie n 4 s ( is tu -T Xu d) q ;chromosome. ----—---- ------- ———i —— --—---- - -----e--- R Susu 728 159 42 1156 : 4 7 . 6±F 12 .5 3 • Fx O C Tutu 102 53 41 8 184 : 5 7 . 0^4 .0 1 F R Bnbn 252 143 101 19 5 1 5 :3 4 .7 *2 . r 52 5 B R Bnbn 9 41 15 6 4 1 :3 6 .6 98 which induce me to think (bd) located in 7 (ra-gl^ chr -losome. This summer I shall have the linkage (bd) with larger progeny. 6) I have genes ts^, ts9, ts^ and I am aware oi. the genes Ts~. All these genes produce grains on tassels and in ts , ts, 7 ts there is nearly always a complete replacement of maie flowers by female. Ts* produces also grain on the tassel. small ovary with a sport silk or without it is developed in the hermaphrodite male flowers in which seeds are never formed. Anthers are nearly normal, but pollen degeneration occurs so after tetrads during the formation of pollen walls.^ k_is asso elated with a strong sterility of female flowers, hi link ned o with su. I have sent you the drawings of hi m^le tlow A rt s . the same time I am sending you small quantity of oeed Hs1, rSp, cr^, — > — > , — anc* ^ 2 * "̂*'67 ^ gl el g l I n autumn I will forward a series of cha 1 racters _9 6 10 after testing their mode of heredity. Some time ago I read your paper on plasmatic sterility in the Journal of Genetics. The results which I obtained and men- tioned at the time in my letter to Dr. Karpetchenko, .hen P a msa dena, are completely identical with yours. The experimen with artificial infection of seedlings cy fresh ju^ce from flo’. cr ine ears showed mo, as in your case, negative resuits. how i ev «e mr ,, inclined to consider this phenomenon as a result occa sioned by the virus diseases. Presently in connection with 1 vestigations of the Mendelian type of male sterility from d 3i 5f ferent sources I came upon 4 cases of plasm^ti^ sterility. One type of plasmatic sterility inherited in F1 through pollen I have in sorghum. I am studying it presently. In regard to the work of the Mendelian type of male-sterility i |°t:y s ~elf in connection with Dr. Beadle, through whose kmdne ceived all his genes of male sterility. With best wishes, I am Sincerely yours, (signed) M. I. Hadjinov.” Unfortunately the seed Hodjinov sent was received too late for planting here at Ithaca last summer. Jexu fall, however, we shall have seed available for distribution. 99 Corrections and additions to list of genetic factors (See maize letter of January 2Z? 193b) (antherless) Hadjinov , a f•raostripe) is allelomorphic with i$ (isjap). The symbol bd is for branched silklcss. The character branched sterile is non-existent. (branched ear) proved from tests made this summer to be alle- lomorphic with bd. bno (bruwn alourone) is in chromosome S. Sprague. cr̂ (crinkly leaves). Hadjinov. d (dwarf plant) is in chromosome 10. Singh. Da9 (dominant aleurone dilutorg In chromosome 9, 6 units from C. Order is Dag-c-wx. Eyster dl (dull brown endosperm blotch). Singleton end Jones, dm (dead leaf margins). Kemp ton '2'6, flr. (floury endosperm) . Mumm. hll0 (glossy Seediins) • In chromosome 1. Emerson. gs (green striped). In chromosome 2. 2 Sprague. hf (hermaphroditic flowers). Hadjinov. j (japonica). In chromosome 4. Emerson. le (lemon endosperm). In chromosome 5. Eyster, lo (lethal ovule) may be allelomorphic v/ith sp. In chromosome Singleton ’ 3E. me (mealy endosperm). Mangelsdori ]22. o3 (opaque endosperm). Chromosome 9. Eyster. pb^ (piebald), apparently non existent, pe (pubescens-hairy sheath). Tavcar }62. PI (purple plant color). Chromosome 6. Emerson 'ml. pm (pale midrib). Chromosome Z. Brink, ps (panicula specialis) . Tavcar hi. rag (ramosa). Brink. rejt (reduced endosperm). Chromosome 5. Eyster ’cl. 100 re (reduced endosperm) chromosome 5. Systcr ’31. t'j rc (reduced endosperm). Chromosome 4. 4 Hs-] (rough sheath - dominant) . Hadjinov, rs (rough sheath - recessive) , Hadjinov, rv; etc. (row number genes), Tavcar. si (silky) (si9 and si are duplicate genes), Fraser si, (silky). Fraser, o suLm (an allelomorph of su). Mangelsdorf. (white seedling). Chromosome 4. Lindstrom. w19 ws (white sheath), Rhoades. yf (yellow flecked leaves). Chromosome 9, Eyster zg (siz zag stalk). Chromosome 6. Singh. 9 Please add these to the list in the maize letter of Jan- uary 95, 1955. We would appreciate it if you would notify us of any mistakes, oversights, etc. Notify this office of any now symbols you may wish to use before publishing so that we can help avoid duplication of symbols. 101 List of maize geneticists ..nderson, E . 0., Institute of Technology, Pasadena, Calif R ,p'idle* G. W., Institute of Technology, Pasanena, R Cr ai lnk i f.R. a ., Genetics Dept., Univ. of Wisconsin, Madison, v,i B su cr .n ham, C. R., Agronomy Dept., Univ. of W. Va. Morgantown, W. r /i ao .k ev, Ira M., 1635 Laurel St., S. Pasad C eo nl al ,i ns C ali.i. G. N. Burea nu of Plant Industry, U.S.D.A., Washington, C o Do .l Ce .r /d . C., University of Wisconsin, Madison, Wise. Creighton, Miss H. B., Conn. College for Women, New Lo D ne dne or ne ,c , C oM n. n. , Carnegie Inst,, Cold Spring Harbor, Long Island, N.Y. , R • A • , Plant Breeding Dept., Cornell Univ., xthaca, N.Y. v s . H . , Jotany Dept., Bucknell University, Lewisburg,^ Pa. Jr\ • c . , Plant Breeding Dept., Cornell Univ., Ithaca, N. G Yu .r ney', HH.. CC.. ,, Vvaite Research Inst., Adelaide Univ., Adelaide H ,a dj Ai un so tv .v, , jM.. I . , Inst. Plant Industry, Detskoe Selo (near Leningrad), U.S.S.R. Hayes, H. K., Agronomy Dept., University Farm, St. P Hu al ul l, , F Mr ie nd n, . Agronomy Dept., Agric. Exp. Station, Gainesvill J ee ,n k Fi lns ^, . M. T., Bureau of Plant Industry, U.S.D.A., Washing J to on ne ,s , D.D. C . F., Genetics Dept., Agric. Exp. Sta., New K Hem ap vt eo nn ,, CJ o. n nH .. , Bureau of Plant Industry, U.S.D.a ., Washington, D.C. Kvakan, Paul, Dobricevo Cuprija, Jugoslavia. Li, H. W., Honan University, Kaifeng, Honan, Ch L ii nn ad .strom, E. W., Genetics Dept., Iowa State College, M c AC ml ei sn ,t oc Ik o, w a.M iss Barbara, Plant Breeding Dept., Cornell University, Ithaca, N.Y. Mangelsdorf, P. C., Agronomy Dept., Agric. Exp. Station, College Station, Texas. Meyers, M. T., F ̂a nr m Crops D .ept., Ohio State Univ., Coaumo M uu sm ,m , OW h. i o.J ., Agronomy Dept., Univ. of Illinois, Urbina, ill. Perry, H. S., Botany Dept., Duke Univ., Durham, R an N.d ol op ah r, . L. F., Botany Dept., Cornell University, It R he ae cv ae ,s , N.R Y. . G., Biology Dept., Agric. Exp. Sta., College S R th ao ta id oes n, , M T. e xM ., Plant Breeding Dept., Cornell Univ., It R nh ao ca ad ,e s N, . lV .. H., Botany Dept., Cornell University S ,i n Ig th h, a cS a. ,, NP .l Ya .nt Breeding Dept., Cornell University, Itha S ci an ,g l Ne .t xo .n , W. R., Genetics Dept., Agric. Exp. Sta., Sp Nr ea wg u He a, v eG n. , F C. o n, nB .u reau of Plant Industry, U.S.D.a . S -,t Wab al se hr i, n gL t. o nJ ,. , D.F Ci .e ld Crops Dept., Univ. of Missouri, T a Cv oc la ur m, biA a. ,, MD oe .p t, of Plant-Breeding, Univ. of Zagreb, x T ah go rm ea es ,, JH u. g oC s. ^, Genetics Dept., University Farm, St. Pau W le ,a t Mh ie nr nw .a x, Paul, University of Indiana, Bloomington, We an nt az ., J. B., Farm Crops Dept., Iowa State College, Ames, Iowa. 102 In addition to the preceding list the maize letters are s<>nt to the following individuals who have requested that the b yeo included on the mailing list. Some of them havu been active in the past in corn genetics but have in recent years become in- active/ Others on the list are anxious to receive the letters so that they may closely follow the progress of corn genetics. jnderson, Edgar, Bussey Inst., Harvard University, Cambridge, B Mr ai se sg er, Friedrich, John Inn.es Hort. Inst., Merton, London, Engla B nr du nson, a. M., agronomy Dept., Kansas State College, Manhattan, Down, E . E., Farm Crops Dept., Michigan State College, Ec.st Lansing Michigan. Dorsey, E., Plant Breeding Dept., Cornell Univ., Ithaca, N.Y. Garber, R. J., agronomy Dept., Univ. of W . V a., Morgantown, H Va ays . , F. /■.., Poultry Husbandry Dept., Mass. State College, Amherst, ,\ A * c' c Hofmeyr, J. D. J., P.0. Marabastad, Pietersburg, South Africa. Hoovur, M. M., agronomy Dept., Univ. of Vi. Va., Morganton, W. H o Vr ao .v itz, S., Univ. of Buenos aires, Buenos aires, Argentina. Krug, C. A., Inst, agronomica do Estado Campinas, Sao Paulo, K Bu rl ae zs iho lv , N. N., Inst. Applied Botany, Herzen St. 44, Leningrad, U • S . S . R . Lebedeff, G. F., Carnegie Inst., Cold Spring Harbor, Long Isl M aa ni dn ,s , V. E. B., Botany Dept., Univ. of Michigan, Ann Arbor, M M ii cl he .s, L. G,, Agric. Dept., Queensland Univ., Brisbane, Austral Ne ia al ., Norman P,, Genetics Dept., Univ..of Wisconsin, Madison, P h Wi ip sp es ., Ivan F., Waite Research Inst., Adelaide Univ., Adelaide, Australia. Richey, F. D., assoc. Chief, Bureau of Plant Industry, U.S.D.A. Washington, D. C. Sharp, L. W., Botany Dept., Cornell Univ., Ithaca, N.Y. Taboada, E. R., Direccion Gral. de Agric., Sn. Jacinto, Mexic W oi .g gans, R. G., Plant Breeding Dept., Cornell Univ., Ithaca, N.Y. Do not forget that the dead line for receipt of news ite is m sN ovember 15th. Please cooperate so that we can make these mai l ze et ters of real service and interest to you. Sincerely yours, 7 rl. 'VTJ. 103 MAJZE GENETICS COOPERATION NEWS LETTER S November 24, 193A Department of Plant Breeding Cornell University Ithaca, N. Y. 104 M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A . N E W Y O R K November 1954 i £ eizc Geneticisto « This letter is composed of data and information v/hich you , c,ve generously contributed so that we can all keep in closer contac be better informed about the work in the different laboratories. mdv , Up r^ evv spk ow n* -s" e— to -o-u— r rec* uest for news items has been good and the in- formation included in this letter will be of interest .md value to everyone. Host, if not all, of the information listed in this letter has not been published so we wish to emphasize, in order that there vail be no misunderstanding, that the appearance of information in these series of corn letters does not constitute publication. If you wish to refer to any data you should ask the direct consent of the contributor. Since these corn letters are a cooperative affair it seems just that only those who show sufficient interest to cooperate should receive the letters. Not everyone will have something to contribute end no one will be dropped from the mailing list for that reason. This office should, however, receive an acknowledgement of the re-^ quest for news items even though you have nothing to contribute. We feel that anyone who does not value these letters sufficiently to in- clude his own data has no claim to the unpublished data of others who have generously cooperated. News items from Ithaca 1. Zebra^ (zb^) which shows in seedlings as a virescent and in mature plants as a zebra stripe (transverse bands of green end yellow tissue) shows no crossing over with d^. Oraer is zb^-h-g-^. Classification excellent and viability good. Singh. k. Zigzag stalk (zg ) is linked closely with PI and sm. Exact order unknown. Classification satisfactory. Singh. 3. A dominant gene (Dt) interacts v*ith a^ to give dotted aleurone. Dt does not interact with ag, c or r. Seeds of a-ĵ Ag C R Dt constitution have a pale purple background on which appear the more intense dots. The ratio of the number of dots on seeds of a. Ag C R Dt Dt dt genotype to the number of dots on seeds of a^ a-̂ Ag C R Dt Dt dt constitution is 2 : 3, while the ratio for seeds of a^p a-̂ P Ag C R Dt dt dt to seeds of a^ Ag C R Dt dt dt constitution is 1 : 3.8. These ratios suggest that the dosage of affects the number or else that an P has an inhibitory effect which is 105 proportional to the dosage of Dt is not linked but is independent of a^, a0, c, r, su and Ig. Rhoades. plants which have 20 chromosomes plus the short arm of chromo- some 5 are intermediate in appearance between disomes and trisomes for chromosome 5. The fragment has a terminal in- sertion region as the break occurred exactly at the spindle fiber region. In 50% of the cases a trivalent group is formed at metaphase I, and in 50% of the cases a bivalent and the fragment as a univalent are formed, when a trivalent is formed the disjunction in anaphase I is such that the fragment passes to the same pole as one of the normal 5 chro- mosomes. The two normal chromosomes rarely, if ever, pass to the same pole and fragment plants have never thrown the primary trisome. Through a study of genetic ratios in plants carrying the fragment it has been possible to assign certain gones in chromosome 5 to the long and short arms, respectively. The available data suggest that Vg ys pr and bt are in the long arm of chromosome 5, while bm-̂ and a^ are in the short arm. Whether a gene shows a 5 : 3 or a 1 : 1 ratio in a back cross using the fragment plants as female determines if a given gene is in thej long or short arm. Rhoades. i>n inbred strain gave in Fg approximately 65% of luteus seed- lings. This aberrant ratio was caused by the linkage- of a gene for small pollen with the normal allelomorph of the luteus gene. Small pollen (sp) has 2% crossing over with luteus. A variable percentage of the eggs with the small pollen gene abort giving in different F' populations a range from 55 to £0% of luteus seedlings. Small pollen germinates as rapidly as normal pollen but never, or rarely, succeeds in fertilization. Cytclogical examinations at pachytene showed no visible deficiency. The gene for small pollen is being tested with sp . Rhoades. White sheathg (ws-j) is in chromosome 2 according to trisomic tests, ws 3 shows as seedling and can be class ified ’ontil shortly after flowering. Rhoades. __t---x bt-, bm, gave 13d8 + bn, : 1 ++ : 2 bt-, bm-. : 119 bt + btx + 1 1 1 1 1 which gives 1.2% crossing over. Rhoades. + -f + x pr bm^. pr bm^ v2 0 - 232 c - 235 1 - 194 region 1 = 43.4% crossing over 1 - 201f , region 2 = a-a.3% crossing over a — 77 Coincidence ~ .80. a — 84 1-2 - 40 Rhoades. 1-2 - 46 106 Branched ear (bo) is alle 9. lomorphic rrrith branched silkless (bd)Rhoades. 10 The studies on nutation and tetraploidy induced by heat troat- 1 * merits arc being continued. The first seedling crop in the greenhouse this fall gave two new mutations, a glossy and a white seedling, from less than 100 Fg ears tested. Randol n. Treatments to obtain 4N commercial hybrid strains were repeated this past summer. A number of 4N plants from commercial in- breds treated a year ago looked very promising early in the season but failed to mature seed, due largely to unfavorable cultural conditions. Randoloh. it The E-type chromosomes produce marked sterility alien present in numbers higher than 16 or 18, and are structurally unstable. Randolph. pg i. survey of chromosome morphology in different strains of maize has revealed types of Indian corn from the southwest which are more nearly like teosinte than any previously known. Randolph. 14, Perennial teosinte in the greenhouse this fail was pollinated abundantly with corn pollen from liguless brown plants to obtain haploids, and odds are being offered (3 : l) that if any are obtained they ’will be annual. Randolph. h summary of all data now available indicate recombination per- centages as follows for the group of g^nes near the end of the known linkage map for chromosome 1 Number of Per cent of individuals recombination P-tSp 3196 1.3 P-zl 1567 1.6 P-ms^Y 3.0 The order of these four genes is unknown. rnnerson. 16. My collection includes ttm following aleurone-, anther, and silk color combinations, in which " + " indicates colored and li-'i colorless aleurone anther silk Rpg + + Rgg + rrr + + r&r + r gg I need the following :- 107 A1curone anther silk The nearest approach to this in ny former collections was Navajo-patter colored aleurone, colored anthers, and colored silks. Colored anthers appear always to be associated wita some color in glumes, sheaths, brace roots, etc. and, except in the presence of B, colorless anthers with colorless glumes, sheaths, and brace roots. It is of interest to note that, if this series of supposed allelomorphs is an example of very close linkage, Webber was probably the first to re- port linkage in corn (Webber, H. J. - Kept. Amer. Breeders’ assoc. k : 76-81, 1906). Emerson. N ew s items f r om C o lumb i a, Mo . 1. is located on the longer arm of chromosome 5, not far from the insertion region. This is the cytological position of Df 5-, , which includes V^. Linkage data indicate the Df is between Blu and Bv, very close to Bv. The Df does not include Bm1, Bt, or Bv. This internal deficiency markedly reduces crossing over, Doth in the Bm-Bv region and in the Bv-Pr re- gion. This shows that in maize crossing over may be inhibited by deficiency outside the region homologous to the Df, which appears not to be the case in Drosophila. Stabler. 2. A new high-mosaic strain gives endosperm mosaics with a frequency higher than that ordinarily found in heavily X-rayed ears. The various endosperm loci show differing frequencies of loss corresponding at least roughly to their relative frequencies in common maize. The high frequency of chromosomal aberra- tions is limited to the early divisions in endosperm develop- ment, the proportion of small sectors being hardly more than normal. The factor responsible for this effect is transmitted through both male and female gametes. The chromosomes derived from both the male and the female parent are affected in en- dosperms which have received this factor from either parent. In an F progeny segregating for an unknown yellow seedling factor and for the high-mosaic factor, seedlings sectorial for the yellow seedling character were common in th^ progenies with high mosaic frequency. Plants heterozygous or homozygous for the high-mosaic factor are normal in development and have normally fertile pollen and ears. Stadler.3 3. Dr. Sprague and I have begun some work on ultra-violet treatment of pollen, with the collaboration of Dr. F. S. Brackett of the Smithsonian Institution. The experiments haven’t gone very far as yet, but it is clear that ultra-violet treatment of pollen induces genetic changes which show up as both whole endosperm and mosaic endosperm deficiencies at rates rather 108 "ur-jrisingly high, x single progeny n growing in;,™ oe w growing* l is n the greedi- o 1 shows about 10? of tnc pla p no tl sl e wn i ts ht e sr ci gl ri st gJ ting y. The results thus far therefo ■ re .t ct h oe rr ec sh pa onn dg .e .s to bo expected froia an X-ra o y-' l el ren c, ^ uw ,i H.t nh t of jrequencies corresponding to a dosage p o o fn s Xi -d re a r yn sb '• y lower tho.n the- maximum u .l tr Ha o- v.v ei vo el re ,t tr ha ed i ca lt osi eo sn ou is ed were also well below th P ee s mu ai xts x af uro ni' .i filtered end mono chromatic ultra-violet t i lo tn cis c -.e re not yet uvnilabxc. obe-dlCi ® ilin' eOgo* dc tu. Linksge Re c onbi nat ion: Gene phase Number of individ No. %___ X y XY Xy xY Gsg Lg RBC 17 58 81 19 56 29.5 Os" B 162 4 8 170 12 5.5 Pep R 128 95 58 r • Cj 16 o 5 Pc„ G 204 19 80 50 21.5 Order R--Pc2-g Sprague News items from noreantown New linkage stocks :-^ Chromosome 1 p f. p 1 an b 'r ' b"of b 2n i g , ( p a l e y e l lo w e n a o sp e xr^ J P bn^ y P f ̂ bOg ( s e g r e g a t i n g tS g ) • Chromosome 5 pr b t bra ( n o t homozygous f o r LCR) . Chromosome 7 r a g l i-j (o r h l e a s t the F ̂ -, 1 in c o u p l in g ) ± Burnham. New characters : - Several characters .a re either . segregati _ng o c ro n ad ri et io inn hi on m ot ^h ye g ni an bred lines here at iiorg a ar ne t ot wh ne . fo nl ul oo nw gi n tg h: ~r .i glossy seedling, tassel s w ei et dh , n ro ar nm oa sl a e ta ar ss s, purple seedling leaf colo s ru n w hr ie cd h in i s na ait lu ur oe t : plant. This 1-st character is c. domin^n •• Burnham. 109 cQ i—1 -J 6 o f,-]nkagc data including o ic•*'» to w. o.. with unlinked genes - 2 poirr tests o- Number of individuals • • Ne* coin- Genes x y Linkage » ~ : X Y X y} i, Total: oinatxon. eh a s c x Y . x y . . Ho>: Y t*, . i ] R S 437 1 1 1 : fc.01 : 4 : 754 : - :19.,0 l J • l l Vp ysi * C B 1-Lb 43 : 51 : 113 : 325 : ~ :30.5 R B 153 £76 : 30b 8in :y s 11 2 3* : 860 :276 : Z a . l C B 150 37 ; 33 : 111 : 331 : 70 :21.1 tiLl x 1 S l X _ : : : : :less 4- bt bn^ bt — 260 46b i 173 : 0 : 897 : :than : : : : : ll.. bn C-, B 111 101 : 198 v : 0 115 : 625 :299 : R B 182 135 : 221 : 150 ‘ 666 :312 : bnn ch * C B 104 98 i 106 i 89 i 387 i 204 ° yg? C 3 113 1c 0h 3 * : 97 : 84 ; 587 :200 ; hot yg-j* C B 163 136 : 142 -L : .. 1-—4 4s 8 .. :. .— 5 8■ 9— :278 :47.2 : ; : : i bug ch C B 57 48 : 46 : 36 : 187 : 94 : g2 Ch C B 59 57 : 61 : 47 : 224 :118 : X Y Ygn - T4-5u C B 32 15 * 5 : 17 : 69 : 20 :29 _ ._ 0J*.. .....—•— hn - T5-7n * R B 5 128 : 95 : 14 : 242 : IS : 7.9 * Those include those in the 5-point tests. Burnham. Linkage data fr ,n a 3 point Fg test : : P G re netic : pr: : Bt : bt :c ons Bt ti tut : e bt :Totalri: : + :vp2: + :vpc.: + :vp2: + •’ vp2 • • • • 1 r + Vi'8 1 Uoip.0 7 ; 55 j 1 *| 84J 14 J 200J 1*: p 9r 9 1 bt + ; . . . : : : : • • : :• • : : : : : ^ ft Not c or twin that these are vp grains. The rocon bination percentages are calculate:* as though these were vpo• pr - vp g = Jef/o bt - vpo(2/ - 10;'c pr - bt = 15$ Burnha 110 r Linkage data from 5 point back crosses : o - • 6 Genetic Regions Total constitution 0 1 : £ : 1, is + + + * 79 - 70 bO - 1514b - 55** 6 - 1 149 1 7 ^ : 7 £66pr ys vg 15.8%: 50.8%: 81 - 87 15 - bl: 6 - 5s 1 - 1 bn-i_ + + 167 34 : 11 : b 214 + Pr ys 16.8%: 6.1%: + + + 118 - 79 bl - bl:11 - 10: 0 - 5 bm pr ys 197 4b : bl : 5 b65 (also sog. 3:1) 17.8%: 9.3%: + + Ch 61 - 45 59 - 5o: Tx-7 + + b9b — bOl 6 - 7:b0 - b5: 1 - 0 495 15 : 45 : 1 55b — g i r n b.6%: 8.3%: * vf classification was net entirely satisfactory. Burnham. 6. Notes on the above data The linkage of T4-5a with yg is the first found for yg^ If it is in chromosome 5 it must be out in region where v0 is or e/on nearer the end. Or' course it may be in chromo- some 4. The break in each chromosome was near the subter- ninnl knob. The data on chromosome 7 are mostly from inter- changes. In T5-7a both breaks were near the subterminal knobs, while in Tl-7 the break in 7 was on the long arm not far from the spindle fiber insertion. The data indicate that Bn is out toward the end of the long arm, with ra near the break in 1-7 and gl^ in between. Vp^ apparently is on the bm^ side of pr. Burnham. 111 ^^ta'tmeusuro (K & E) has been foun th de vl ee rn yg t uh s eo ff u lc h Ir no m no es eo sm ue rs. m By - t d rr e- ev i' ni gn "° tv h; ei th co rt nh ee r ..u a l. up tm 1e ^a ”s ure the i lc et no gr tst h i (s i n re ig ni cs ht ese re od r .Ca en n.t ih u e - s de if au ll i an f d te ht e er asm ;i n si un reg . arm T hil se ng it s hs 8 8 en8 d 8 re la0 t iveT h le e nm go to h sm e oa fs u tr ne e was G sue g8 gg ee s‘ tV er dB u br y h ae n, enan g ini en e rPE ,R*, project hero at the E S xt pa et ri io mn e. nt Singleton. i ■. *_ • ~.v-, c •'r* Piittv c tions to J C- 31 8 ? y eaTh r! 1 s g n^ on to e sr .Joso has appeared In .an i on tb hr eo rd . s toI ct k , ha as Lp ero Tve On allelom t ohe r phf io cu rt vh i taj c re ^u nr *r enc Te h iso b f) tP hr ie sl i gm oi nn ea r my t oe us rt s s tw oi ct ksh . la, give an wi it nh d icsu a. t ioK n ) olc ro ls is no kv ae gr es occurred in a row i os x p ^r 0o b pa lb al ny t sa ,l lel i omorphic to la. c .) ^ iiicropylo color Me is a modif r yat ih ne gr ft ah ca tn o r al ol f el to nm eo r Pp h fi ac c. t o.,B ackcrosses of E _ to pne shov-.ea a segregation into PHc, Puc and P plan o tc sc ur vlif i cM he cw oe ur le d na ol tl elomorphic to P. Singleton. a) 8 h o factor o r has shown linkage with ra.no sa (C.O. c 1e 8n t p ea rn the basis of Fg data) . Backcross data, will be avail- b) Packeross data havo shown that Ts b oths id loe ao nf d su s. p arT eh ey o n u ta hy e be c-llelomorpnic. c) 5B<.ckcross data of material sent by t h Da rt . w El m ei rs s ob ne t iw ne de in c aT ts e& and su. The order proaubly l TSc-v. b l-su-Tu. Singleton, jJc-Vv genes or reoccurrence cf known - ) g er nu em ^osu Sweepstakes inbred. It is bein b gr o tw en s tu ei da r vi /ib uh b - r S aw ^.e epstakes inbre g dl , c ossyCountry Gentleman inbred, d glossy (not 1, S, or 3) Sweepstakes c ir ni be n r k el dy , — Sv/eopstaKcs inb f a r d eh ue .r ent tassel - S’veep stages y e il n£ l b o rw e d,s tripe - Sweepstakes h y i e nl bl ro ew di ,s h japonica - Sweepst y ae kl el si o w ii ns bh r et dh readed - Sweepstakes inb d rw ea -r uf . 3 — Sweepstakes f ii nn be r ek s d t .r ipe (nay be allel. to . f , p A- Sweepstakes inbred. Singleton, 5 . soft starch (h) of iiumu is different from o bp oa tq hu e o pS a. q ue 1 S ai nn dg leton. 112 i^ylrxeoua sugary (suftn) is allelonorphic v;ith su. This new sugary gone is expressed only when another gone, Gu, va p ir ico hd uces a cull endosperm similar in appearance tc v/ax s yt a bi un ti ng blue instead of red, is also present in the reces- sive condition. Ratios in most crosses arc 15 : 1. The gene suau shows the sane linkage relations as su wh g io ln ee td hu e ^i s located in the R-g group. The new sugary is no a ts good a character as the original sugary but it has b e sa or mi en g on the inheritance of pseudo-starchiness, t th . e st yi nc - pseudo-starchy can be produced by crossing amylaceo s uu sg ary with true sugary. Seed are available. Mange lsdoro. Tn Tripsacum hybrids with maize the number of Tripsacum chrom s oo -mes can be determined by an examination of the poll P el na .n ts with bO Zea chromosomes plus one Tripsacum ch h ra ov me o so50 m e per cent normal and 50 per cent small pollen. Plan w ei st h two Tripsacum chromosomes have kb per cent normal, 5 p 0e r cent small, and kb per cent empty pollen, appa a r es ni tn lg yl e Tripsacum chromosome causes reduction in size diil^ t wo or more cause complete abortion of the pollen. ch Er xo tm ro as ome jlo.nts can ba readily idontifioo. in tne fi p ^o ll dl e b̂n y examination. We now have a large number of stock k sl l having LO maize chromosomes and >nc extra Tripsacum c hr juosouo. Wo ltu attempting to identify these ex s ta rc au m T rc ih pro -ui>s rmes by crossing with corn stacks in whic c hh r to hm e osomes are marked by two or more recessives. b Wa ed l ay r ei n need of multiple recessive stocks for * this work.Mangelsdorf. p few stacks which we have developed lor Texas conditions wh ai nc dh ar« available to other maize geneticists in the South are : - 3 lg aa Bb PI ^1 Lg^ lgg Pp Br br F f Bm bm Lg lg G1 gl Ra ra - Pp Br br F f Bm bm su wx - F^ Lg lg su wx Lg lg Gi gl Ra ra su wx Y PI B lg su Tu v/x aa Pp. Mmgelsdorf ,7e have a number of F plants of uiplaie'. moa x tetraploid Trip- sacum which can be propagated by division. Anyone wishin s gom e of this mater it.1 is welcome to it. iiangelsdorf. 113 1# Linkage data : - Link-1 Recom- : pedi-:Genes age XY Xy : xY xy :Total b inat i on s:authori ty gree : X Y phase N o. % : 9415 •G R S 260 65: 96 3: 4c4 22.5:Lindstrom 9451 sR C S 120 24: 49 20: 213 40.3: 9419 •PI C B 86 r jn « 80 64: 303 153 50.5: » * 9 See : Su w,§> R S 2366 977: 980 159:4482 37.0x0.9: f)4£9 :Tp C B 31 33: 59 58: 181 92 50.8: ]) h new recessive anthocyan gene. y assigned w because the original w in the mimeographed sheets is not shown to be linked with anything, and since the gene is on the new 4th chromosome. Lindstrom. 2. Mev; genes not described or tested for linkage : - a) Dominant chlorophyll striping. Old gold striping (Og). b) a new dominant sorghum tassel. V-.ill not be named until tested with TsR and Tŝ >. ° Lindstrom. News items from V; a shim ton, D. C. 1. In back cross counts involving 227 plants rootless (rt) showed 18.5/0 crossing over with Rg . Jenkins. 2. Lazy (la) shows 11.4/& crossing over with su cjiu is on the oppo- site side of su from Tu and gl^ as b^sea on a 4-point back cross test. Jenkins. 3. u 3-point b^ck cross test with ra^, Tp and indicates the order to bo ra-Tp- ij with the total ra-ij distance about 11 units. Jenkins. 4. Branched silkless (bd). Our r suits agree with those of Hadj inov in that (bd) is not located in the fourth chromosome with Tu. Our latest progeny in repul >ion phase with su gives Su Bd 261 : Su bd 82 : su Bd 4a : su bd 14 with less than 1. The deficiency of su plants is accounted for by the poor s t and. Kemp t on. 114 1. h1 lb^ ■1v > 6cf x re; Ll L'c2 1'6£ Rg o igy rg j 70 E £'l Lg? kg ~ igr = 36.0% ‘'1 LSo kg 1 1 j 406 Ll ig2 rg Igp - Rg = 15.7% (J nl igg Rg L1 - Rg = 51.755 bgo rg ̂ 138 al "‘1 L££ rg Rg j 60L1 tel 11lb Brink, N L ts* ' 1 4 r e : x a . na ts l’l n e , T s 4 Rg 1 Na ts4 r g - 135 0 1 Grose; = i n1 a1 -ovo^1 na *̂S4 R& 6 a a r ̂f ; ij . C1 — Hu = 13 o l f j ne R —g i— 41 na Tf c4 = 35,7/5 1 *1 TS4N a ts rg 31 113 ts _ Peor ■= 3.7/ ’i 4 4 N i rp c, ni - Rg = 40,91 R-iX ~b4 Rg = 140 4” c bl ne L54 rg 105 145 o A1 Na ts4 Rg - £4 na ip~ °4 rg — 17 51*x ^1 ns ts4 rg = 311 & 1 Na = 56 68 o TS4 Rg na Ts^ rg = L. 1 & 3 “Xl al Na ts4 Rg = 9 13 A1 Na Tlqb4 rg = 141 & 3 al na ts%. Rg — 5 17 c. A1 na ts4 Rg = tsj Gi N a Ts4 rg 3 — 5 Total S90 Brink 115 (lg0 x na) @ No lgfl no. plants appeared a along about. oOOQ oil spi ing. Th.̂ j result does not tally with expectation on the basis of the above results* viz, (lgg ~ Rg - 15• *7/0 o»o,9 *.110 ric; — Hg 4 0 ,9$ c.o.) (&n-n& = 25.1 %, c.ncl a^-lgg - 36.0%) . 1 Brink. Lgg 1 ■ lg = 162 b do - Rp D1 o 2 > 162 d11 bgg Crossing-over h Lg£ \ 96 lg„a - d. = 571 .2!* dl ^ 2 >. Total a 58 Brink. h_!£ x a rg Dx rg d Rg L9 D 1x rg Cro5oxn*,-ovor D1 Rs 94 Rg ~ di ~ ^.4#d1 rg Totel 585 Brink. na Pa Jin ;x na pm rg pale midrib Na pm rg Numbers na Pin Rg = 125 Na pm rg = 189 . _ 514 Rg - na - 40.3>-. c.o ila Pm Rg = 109 na pm rg 57 _ 166 n& 1̂ nr* .n- = 710. 79 %f'S " Na pm naRg = 15 pm - = 33.1 >c na Pm rg 21 34 na pm Rg = 1 Na Pm rg 5 6 Total 520 Brink. 116 r-' li 7. A.. Ba^ Rg X a bâ _ rg Cv 0 C v I* ̂ A Ba Rg ) 20 rg ) - bL-i A ^13 C .1 rg )r_ { 16 Crossiny.-ovcr a*. j B* a t a a / —_ c**. „ — 36.8% 1 rg 3 ba — r .. C> j- Bi-i 10 - Rg . jC/O *• b4 Rg ) 1 - Rg - bp .iL . ia. /oj’ Rg \ " 1 L Iiai rg ) ( Total = 49 Brink. 8. Rg Ra.c, x rg ra r an — r n.uio s a.2 re TUS Rg p" 2 = 38 rg ru9 = 67 Crossing-over Rg ra2 = 26 Rg-ra.g = 34.4% rg Ra q = 29 Total 1G0 Brink. 9. Ra2 = 152 i* r a o 29 ad „ 13G8 “ i x be 1247 Ot Rag - 43 v.i. 9 c.o. = ca 50%ra2 Brink. Nev»s items i'roi.i Pasadena 3 ev»- ;stocks - chromosome 2 1.bX b vA segrega ting c sh wxgl2 ig1 .gl2 B V4 b sk V4 segregating Ig and gl 13 sk 4 f. ft 1 ft b ts„ v i i i fi 117 Chrome 5 o-ic o U" *O0 pr b ^ v2 Pr Ch Ch Ch Ch Ch Ch x v pr bm 2 1 Clokcy Chromosome 7 rax gl ij Cldkoy I j i i i K i ^ g O U t o. * On a back cross of 1100 plants for rax glx ij the order froi the first 700 plants is ra^-gl^-ij with ; cross over value of 4-5 per cent between ra^ and gl^. Clokey. Data from cross ±__11?__± x pi sa py PI + py Py plants py plants 0 : pi sm: 150 PI + : 131 1 : PI Sui: 17 ( pl : 37#w : PI + : 26 1-2i2l + : 0 1 om Py plo.nts only - PI-sat 11i •- — 8o . tW *>/o sm-py 26 _ 13 . 0$ 195 From all slants Pl-py 60 C f v » /w 561 Order is thcreiore Pl-sia-py. mderson News items from Sao Paulo, Brazil No. of strain a) Far and see a cim. ra.cters available 1) pronature gemination (Sol) 1 2) several Kinds of defective endos- perms (shrunken> floury, etc.) 6 b) varicgated pericarp 1 4) mottled alourone 1 118 No, of strains ̂Vc_.il able 5) brown pericarp 1 6) &1ourone colors & 7} semi-tunicate grains* 1 8) branched o; r 5 b) r.r-:,' f characters l ) concentric spots* 1 £) oily spots (?)* 8 3) crinkly (?) ^ 4) rolled leaves i£ 5) ragged (?) d 6) narrow leaves 1 7) hairy sheath f c) Chipriliy 11 -ucf 1 ciant types l) white seedlings 7 1) yellow seedlings ^ 3) several kinds of striped ̂ 14 i) zebra striped seedlings (?) 7 a) Genes affoctin;-; the whole plant l) several typos of dwarfs 13 £) ultra-iv/arf 1 ranosa (?) 1 e) i v bnc r < .it. 1 six-di-, trlbuti o n i) tassel-ear, tassel-seed 4 £) hernaphr. flowers on the ear 1 5) male flowers on the ear* 1 (upper half of ear is f) 4) female plants* 1 The characters marked with * arc suppcsod to be new ones. Some of the abnormalities appeared in more than one strain, but they may not be allelomorphs. Krug. 119 Results of first inbreeding three corn varieties Varieties Total ‘'amarello'' “Crystal1' hl.L\[3uro,i Type of Variations (688 (1052 (72 (l81t Found ear-rows) ear-rows) ear--rows) ear- No. : No. : % No. % No. • White seedlings 12 : 1.74 60 s 5.70 2 2.8 74 4.08 Yellow seedlings 5 : 0.73 5 : 0.47 0 10 0.55 Transv. striped lvs. 5 : 0.73 12 : 1.14 0 17 0.95 Light green lvs. 19 : 2.76 6 : 0.57 1 1.4 26 1.43 Striped leaves 15 : 2.18 9 : 0.85 1 1.4 25 1.57 Concentric spots 1 : 0.14 •• Ragged (?) 1 : 0.14 11 : 1.04 0 12 0.66 Rolled leaves 6 : 0.87 15 : 1.42 1 1.4 22 1 • 2l Crinkly 6 : 0.87 0 : 1- 1.4 7 0.38 Oily spots (?) 4 : 0.58 5 s 0.47 1 1.4 10 0.55 Narrow leaves (?) 0 : 2 : 0.19 0 c 0.11 Hairy sheath 0 : 2 i 0.19 Dwarf s 5 : 0.73 5 : 0.47 1 1.4 11 0.60 abnormal sex dis- •• • tribution 25 : 3 . 6a 8 : 0.76 2 35 1.93 Ramosa (?) 0 : 1 : 0.09 0 1 0.05 Branched car 4 : 0.58 4 : 0.38 0 . - . ——-— - -------- •a •• In 193k; we selfed about 3,000 plants of these three vari- eties. among the 3clfed ears we found a great many with defective endosoerm seeds, one case of ‘'premature germination1' (3:1), one with semitunicate grains, besides a great number of diversily diseased ears which were eliminated. From these 3,000 ears we selected only 1812 for further planting; the variations found among these ear-rows are given in the above table. Krug. 120 CD 1 iw o Sanaa's Vvi'li with plant color pigments In a former paper Sandc and Bartlett shewed that the pip- r:ent in an BB PI PI plants was a yellov/ flavonol glucoside, iso- quercitrin , Sando* milner and Sherman have a paper in press on the nature of the pigment in An B3 PI PI plants. This purple •pigment proves to be the anthocyanin of isoqucrcitrin, chrysan- themin. To quote Sando: "If it is assumed that the anthocyanin in purple-husked maize is formed directly from the flavonol glue oside the reduction representing the possible formation of chrysanthemin (as chloride) from isoquorcitrin may be expressed briefly as follows: Cl 0 OH 0 X\X\_Xx ~ \ o H H0/ \ X \ HO \ -----x — > X ° E °-C6Hli°5 w °-C6Hll°5v V isocuercitrin - Cgl HggC^g Chrysanthemin Cl - C H H Cl.21 20 11 Inbreds resistant to smut In the corn letter of September 12> 1934, we stated that we had several inbreds which were resistant to smut under field conditions here at Ithaca ijid that it seemed desirable to cross some of the more susceptible genetic stocks to these inbreds pro- viding they proved resistant when grown at other stations. Hayes writes that they have made extensive tests for smut resistance at Minnesota and have inbreds which were resistant to smut brought in from various localities. This material should be ideal for our purposes and Hayes has kinaly offered to supply a limited amount of seed for testing next summer. V;e should like very much to send snail lots of seed to four or five different stations. If you are willing to grow this material and note its resistance to smut under your field conditions, please notify this office. 121 Miscellaneous The following changes and corrections should bo noted X. The symbol dt was originally given to the character dotted leaf. No description of this character was ever published it was never linked, cjad the stock has been lost. There- fore, the symbol Dt has been assigned to dotted aleurono (see news items from Ithaca). 2 , glj_Q v;as erroneously reported in the news letter of last year as being linked with f^. The striped character proved to be instead of f^ and the glossy is gl^ instead of a new gene. N1 was reported as showing linkage with a^. More extensive counts failed to substantiate this linkage. 3. The names of A. E. Longley and C. E. Sando have been added to the mailing list. Both are with the U. S. Department of Agriculture at Washington, D. C. We hope to issue another corn letter in the spring. This letter will include such news items as are sent in and a more complete list of genetic stocks. Sincerely yours, 1, )Y] , 7b. 122 MAIZE GENETICS COOPERATION NEWS LETTER 9 March 6, 1935 Department of Plant Breeding Cornell University Ithaca, N. Y. 123 c P M A I Z E G E N E T I C S C O O P E R A T I O N y D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A , N E W Y O R K January 21, 1935 To Maize Geneticists This letter is a call for lists of new genetic stocks, news items, etc., for another corn letter which will be issued around the first of March. Please go over your genetic testers and list any new combinations you have developed. Also send a small sample of each stock to this laboratory and we will in­ crease it for general distribution. News items are, of course, always welcome additions. The dead line for receipt of this material is February 15. Your cooperation is not only desired, it is essential. Sincerely yours, (signed) M. M. Rhoades MMR:B M. M. Rhoades Letter sent to: E. G. Anderson, Beadle, Brink, Brunson, Burnham, Clokey, Collins, Eyster, Hayes, Jenkins, Jones, Kempton, Lindstrom, Mangelsdorf, Perry, Singleton, Sprague, and Stadler. 124 M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A , N E W Y O R K °\ March 6, 1925 To Maize Geneticists i - This maize letter contains a list of new genetic stocks, as •-r„3mnil asr- a consiiudeerraaubilte' numubceir ouix news itev me si± , . r s e; v e, ral new. s-i tocks 2re listed in the las, ,t4. maize Tl,se+-t-Fr,,- .— ter» -_ rt vh-i ey ’..ill nnoo tt hbeer rrrenpoesatteedd . „rp The response of the Various investigators to the reQuost for material has, as heretofore, been gratifying and has made possible £•^^3 series ol maix.e letter^. The new stocks have been grouped together as follows: From Sinftlcton Chromosome 4 stocks: ni. + su 1Tu vr V + L 1I11 su tu.  ■ su X ts w1 su. wl + + wl + + a. su 4. su s£ 5. su lo 6 su + 7. + Sp* + + + + lo 8. wi S\I ♦ Q Ts_̂ + su + x 2 ' Z) • Fo. 10 wl + tu su g!3 + wl su 2 wl su tu Stocks other than chromosome 4: Chromosome 1. P tSg i \ bm2. Chromosome ts* • v. if1 glP lgi and lg! gig v4 h C rg Y Su. Chromosome 5. bm̂ pr. Chromosome 7. glp v5 seg. ra­̂ and gl­j_ ij Y Su. From Burnham Chromosome 1. U an bmm k6­33j« to 5­1^; ­ Bm reduced fron 4­6y to 1/t) . Cytologies 1 observations indicate that this effect may be genu/m 1 for internal deficiencies. This means that backerosoes of non­deficient individuals will have to be used for final mapping, but the non­deficient sibs of the sane crosses may be usea for this. The reduction >f crossing over in the deficient plants will be an advantage in reducing the genetic length of the chromosome so as to permit the detection of link: ge over longer­ actual distances. It might be worth while to construct haplo­viable Df stocks deliberately for this purpose, particularly in the case of the longer chromosomes. Probably >no well placed Df would do for each chromosome. Preferably the Df should include a locus somewhere in the middle region, and the dominant marker used should be far enough away for fairly frequent crossing over. The dominant should be one not likely to occur in the mutant stocks, as P, B, Rg. Ch, PI, etc. The recessive should be a seedling character so that a large number of plants may be examined in looking for the induced deficiencies. Such deficiencies may be obtained by irradiating the pollen of the dominant stock, pollinating on the recessive, growing to maturity the F;p plants showing the recessive character, and pollinating all which by their plant development and pollen development seem likely to be haplo­viable deficiencies. The best pollen to use on these plants will be pollen carrying two (or more) recessive markers widely separated in the chromosome. Then, v/hen the Df plants are pollinated by the new mutant, the Df progeny may bo used as out­ lined above and a few non­deficient sibs may be selfcd to provide F' material with 'widely separated markers, for accurate mapping if the Df test indicates linkage. Thus, for chromosome 3, a suitable technic would be as follows: Treat Rg and pollinate on l£g, save 132 only l£o seedlings, and pollinate suitable ones by a The Rg (lg )"/ plants thus secured are suitable for pollination by thĉ nev; mutants, and the Df stock is maintained by pollinating in each generation by a and using only the Rg Df plants of the progeny. If any corn breeder not having x­ray equipment available wishes to make up such a stock for his chromosome, we should be glad to make the necessary treatments and pollinations for him here next season, using th stocks designated by him for the pur­ pose. Stadler. News items from V/ashingt;n, D. C. From a perennial tcosinte­corn hybrid has been isolated a cornlike strain with 20 chromosomes in ­which chromosome IX has a terminal kn'jb on the short arm and a large internal knob on the long arm. Measurements show the terminal knob to be approximately 0.3b of the whole length of the chromosome from the spindle fibre attachment, the internal knob approximately 0.52 of the whole length of the chromosome from the spindle fibre attachment and approximate­ ly 0.15 from the end of the long arm. The terminal and internal knobs are frequently stuck together so that at first it gave the impression that the loop was due to the pairing of a normal IX with a IX that had an inversion. Seed of this strain is available. A. E. Longley. News items from Bucknell University 1. A new fine­striped* chlorophyll pattern in Chromosome 10 cas in­ dicated by its linkage with the R aieurone color gene. R r R St R st r St r st Backcrosses 1206 1213 822 121 203 776 Crossing over ca 17^. *Ed. note: This gene is f„. 2. Bm­̂ in chromosome 5. Field grown Bn bm Approx. Ratio Group 1 2495 765 3.27 : 1 2 633 101 6.27 : 1 'Z 1055 64 16.48 : 1 4 292 3 97:33 : 1 133 g) Greenhouse grown Bn bn Approx. Ra. tio Group 1 4456 1510 2.95 : 1 L* Eyster. 139 The reagents employed and the sequence of transfers from fixation to paraffin­ribbon mounts are as follows: 1. Fix roots 12 to 24 hours in "Craf" (Chromo­acetic­formalin): Solution A, Chromic 1 gr., Acetic 7 cc., Water 92 cc. Solution B, Formalin 30 cc., Water 70 cc. Mix equal parts A and B just "before using. This fluid was developed primarily for making chromosome c i on u nt th se root­tips of maize, but it has proved to be very useful for similar studies in many other plants. 2. Transfer roots directly from Craf to 75% alcohol, changi s nev ge ral times at half­hour intervals to remove most of the fixing fluid; then to 85^ alcohol. 3. From 85^ alcohol to normal butyl alcohol as follows: (1) HpO 15 cc., 95^ ethyl 50 cc., butyl 35 cc. (2) * 5 cc., " " 45 cc., n 55 cc. (3) Absolute ethyl 25 cc., butyl 75 cc. (4) Normal butyl, 3 or 4 ctenges. Leave roots at least an hour in each solution, 2­3 hours in pure butyl. 4. Infiltrate gradually with paraffin: Add melted paraffin po (i mn et l ti5 n4 g­55° C.) in an amount equal to about one­third th o ef vt oh le u mb eu tyl alcohol covering the roots. Add the paraffin s s lo o wi lt y will solidify on top of the butyl alcohol. Plac r ee ce thp et acle (preferably a 30 or 50 cc. pyrex beaker) conta t ih ne i nr go ots and butyl­paraffin mixture in a paraffin oven at 5 L 6e av Ce . over night. As the paraffin melts it passes slowly b o tt ot o tm h eo f the beaker and gradually infiltrates the roots. nex Tt h e day pour off the butyl­paraffin mixture and add pure liqu p ia dr affin. Repeat 3 or 4 times at hourly intervals. 5. Embed, cooling the paraffin rapidly in ice water, 6. Prepare cross­sections 10 to 15 microns in thickness, gp r ri eb ab do ns on slides and dry for several hours at about 40 C. 140 To facilitate the handling of root­tips in the paraff m io nu n mt ee td h od they may on cards in the following manner. 1 Prepare small pieces of heavy paper approximate ' lyi n 2 s ci m.z e x (t 2h .e 5 h ce ma .viest grade of Y and S filing ca S rm de sa r i s th se u ib ta as be l e)o f a card with DuPont househol w da t ce er mp er nto ,o fi on rg Lc ee Pm ae gn et . s Add roots and cover with more cemen a tt l le ea as vt i n. g5 cm. of the tip of the root free ( o fn ic ge . i Dn . the I nf vi ex ri tn g a tf luid, keeping the cards separated until the cement has partially Hardened. 2. After fixation and transfer to 75$ alcohol, sni t ph e o fr fo o tt hs e f tr io pm s ^t oh fe original card in a petri dis s hm a cl ol n ta am io nu in nt g o af alcohol. Prepare a second smaller i ma cat re dl ,y a7 px p ro12 x m in size. Label one side (Pig. 2a t )h ,e ao nt dh e cr o as ti de with a thin layer of nrocilage, u a sm ib ne gr ­ ac o cl lo er ae rd , grade of Carter’s or Stafford's muci t lo agt eh e ec vo an ps oi rs at te en dc y of heavy syrup. Rapidly transfer b thy e o rne o otf sr o om n et he petri dish to blotting pape e rx c fe os rs ra el mc oo vh ao ll , o fa nd then to the second card. A d d a n mod r ea mt uh ci in l as gt er ip of paper to help hold the roots i I nm m pe lr as ce e t (h *e i gc .a r 2d b Kwi th roots attached at once, ri a gl nc to h so il d. e uT ph ,e im nu c di bl a , ge may be conveniently applied with a. ho. 2 or No 3 camel­hair brush. For transferring the root t sh e qb ul io ct xt li y ng : rp oa mp er to the card a bent dissecting n to e edc lb ee r ao pl pd lit e ds urface of the root is very effe f ci tn ia vl e o (r Fi ige .n ta 3t ).i on mo ef the roots on the card m t ar ya n bs ef e cr o mt po l e8 t5 e$ d a al xc oo eh ro l. The root­tips s h o u l d project 2 am pm p. rob xe iy mo an td e lt yh e edge of the card, and care mu t si tp s b ea r te a kk ee np t thf ar te e mo ef mucilage since it causes trouble in sectioning, 3. After the mucilage has hardened the card mount 3 s0 ac rc e. po lr a c5 e0 d cc i. n ap yrex beaker and dehydration and ar ie n fc io ltm rp al te it oe nd in the usual manner. The mounts s w hi ot uh l dt h be e l ea mb be el dl de ed d side down so that the mounts r me aa yd i bl ey . identified Paraffin ribbons from two or more card moun m ta sy be placed on the same slide (Fig. 4). 141 L. P. Randolph X place slides in xylol to remove the paraffin. Flush with fresh xylol, t hen with absolute alcohol. Pass the slides successively through 95$, 50$ and 30$ alcohol to water, 3­5 minutes for each step. 2 1$ potassium perraangenate, 2­3 minutes. Rinse in tap water. 3 5$ oxalic acid, until the sections are bleached ­ usually 1­3 minutes. P rolonged treatment with oxalic acid sometimes causes the sections to come off the slide. Wash in tap water 15 minutes. The bleaching process in permangenate and oxalic is not always necessary, but it usually adds contrast. 4. Mordant in 1$ chromic, 20 minutes. Rinse in tap water and then in 2 or 3 changes of distilled water. 5. 1$ aqueous solution of crystal violet, 4 hours. It is often desirable t o vary the staining period. If the stain comes out too rapidly in the alcohols and clove oil, leave the slides in the stain longer. If destaining is prolonged, shorten the period. Rinse in tap water. 6. Treat with iodine­potassium iodide (iodine 1 gm., potassium iodide 1 gm., 80$ alcohol 100 cc.) until the color of the sections changes from blue to brown, usually 1­2 minutes. 7. Rinse in 95$ alcohol and pass through 3 changes of absolute alcoho c llo v te o oil. Differentiate in the alcohols and clove oil, ordinarily 1­3 minutes. Watch the process in the final stages under the microscope T .h e raetaphase chromosome groups under a 16 mm. objective should stand s h oa ur tp ly against a practically colorless background of cytoplasm. 8. Pass through several changes of xylol to remove all of the clove oil. Mount in thin xylol­balsam. After the cover glass is in place invert the slide on paper toweling and apply mild pressure to force the excess b alsam from under the cover glass. Add a few drops of xylol to the edges of the slide, cover with another paper towel and a piece of hea g vl ya ss, or other suitable weight. As soon as the slides are dry they b e mae yxa mined. This method of mounting removes all excess balsam and brings the cover in close contact with the material, so that high­power objectives may be used with greater safety. 142 Pub lieat ion of new linkage data It has become increasingly difficult to secure publication f o''oers presenting linkage data for new genes in maize. Some entitle journals refuse to accept this type of work for publica­ Hrn. Yet it is extremely important that a short description of characters and a summary of the linkage date, appear in some recognized Journal so that this information will bo made generally Available. •> In conversations with Richey, Jenkins end Brink the recent Pittsburgh meetings the following solution was suggested: ^"That there be published annually a paper under the general heading New L in k a g e s in Maize1, or some similar title, which would present short descriptions of new characters with tne linkage data given in sun­ dry form. This material would be contributed by the various vork­ ' rY. The name and address of the contributor would appear either before or after each linkage ho reported so that he would get the credit which rightfully belongs to him.." The above suggestion will, of course, have to be developed in greater detail but wo believe it should receive careful considera­ tion from you­ because it offers a remedy to the rather serious problem of securing publication lor new linkt.^oo. The amount of space devoted to each.character will have to^bo limited to not more than one printed page and preferably less. This allotment should prove sufficient, although seme leeway would, oi course, be permitted. This proposed publication is not, in any sense, to be considered as supplanting the maize letters because as we have so often reiterated, the* appearance of information in the maize letters does not constitute publication. If this proposed annual paper of new linkages will not oe acceptable for publication in one oi the* Journals, we suggest­ tbu.t space be purchased at so much per pag^. For the next four years at least there will be funds available from the grant made by the Ro c k - efellor Foundation to the Maize Genetics Cooperation which ern^be^ used to pay for the publishing of this paper. One attractive featur­ of purchasing space is that v.e could secure immediato publication. The* contributions from the various investigators would ec ediojJ and compiled by the Secretary of the Maize Genetics Cooperation. Give us your opinion of this idea and, more import, nt, would you be willing to take part in such an enterprise ? Below is a copy of a letter ’which was received from Jones ̂ in response to an enquiry as to what he thought ol the idea from his point of view as Editor of GENETICS: "Dear Dr. Rhoades: I am much interested in your suggestion as to a way of publishing linkages. I should like very much to try something of this kind and see no reason why it would not be acceptable in GENETICS. I agree with you that the information should be published but^in the past, authors have usually expended each individual 143 case of linka ge into a 5 or 6 page paper or more, und facilities have­ not permitted the publication of this much material. If each item could be con­ densed into a page or less, I think the arrangement would be advantageous for all concerned. Some pro­ vision would have to be made for references so that each separate contribution should have a main head­ ing together with the author’s name and address. The principal difficulty that I see will be to get someone to summarize this material and get it in shape for publication. If you are willing to do this or anyone else can bo persuaded to do it, we shall be very glad to do cur part. (Signed) D. F. Jones.” Inasmuch as I an severing my connections with Cornell to take a position with the U. S. Department of agriculture at Ames, Iowa, I necessarily an relinquishing my duties as Secretary of the Maize Genetics Cooperation. Until, however, Dr. Emerson appoints my successor I shall be willing to continue to act as Secretary so that there will be no lapse in the functions per­ formed by this office. Until March 20th I can be reached here at Ithaca and after March 20th at Ames, Iowa, c/o Department of Farm Crops, Iowa State College. I wish to state that I have really enjoyed my work with th< Maize Genetics Cooperation and I hope that my successor will re­ ceive the same fine cooperation from the maize geneticists which has n:xle possible this unique series of corn letters. Sincerely yours, ~)YJ. ~̂)Yj, (I MMR: B M. M. Rhoades 144 The enclosed maps of the linkage groups V;ere made from the data which Emerson has assembled for the forthcoming paper on linkages in maize by Emerson, Fraser and Beadle. Only those loci whose position is known with reasonable accuracy are listed. We are indebted to the Division of Cereal Crops and Diseases, U. S. Department of agriculture, for furnishing the copies of these maps. M.M.R. 145 1 2 3 4 5 6 7 8 9 10 0 0 0 A2 0 v7 0 V5 0 m s 8 KNOB 0 N LY Go B M 1 BV 14 R A ± 18 G L 1 18 1819 GL- 22 PO 21 c 24 SH 25 AS 28 NA 28 TP 31 PR 31 MS1 32 R G a V 34 IJ35 35 T1 38 B 39 BA, 39 BP40 YS 4 4 T 5-7 A 4 5 SK 52 BR 52 B N 54 W X F, 56 TS4 56 Ts, 57 57 FL 57 63 TS, 63 Rg 66 SP 67 Pl 66 69 LO 69 Bh su 70 T 8-9 A71 71 72 74 AN 74 DE 16 77 SM 85 87 PY 92 W, 101 100 Tu GS< 103 CR- 105 GL- C H R O M O S O M E M A P S OF M A I Z E 128 B M I 93 5 146 o r o I-* o > M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A . N E W Y O R K November 30, 1935 To Maize Geneticists: I The summary of linkage in maize is finally off the press aS Cornell Agricultural Experiment Station Memoir ISO, and. a copy has been mailed to each of you. The authors realize tnat this summary is already a year or two out of date, but hope that it will serve a useful purpose as e base of reference for future linkage studies. It will, of course, have to be revised from time to time, but probably a general revision should not be attempted for some years. Your secretary believes that, lor the present at least, it will be better for those of you who are interested in a particular linkage group to publish a revi- sion of that group when you have data sufficient to straignten out any of the confusing and even contradictory situations apparent in many of the groups as presented inthe summary. When one has evidence sufficient for a thorogoing revision of any one of the ten groups, it should not be difficult to fine a place for publication of a concise paper setting forth the revision. Pe „n ding the time wh .en any of us are ready to publish such revision, the data obtained should be made available to others. Moreover, most workers find a miscellaneous lot of linkages the data on which should be made known to the rest of us. In the past many such records have been sent to you in mimeographed form, but always with the caution that such distribution does not constitute publication and that no one other than the one who contributed the data has any right to use them without per- mission ,in a published paper. This is not an ideal arrangement. The data should be published at once. But it is almost impossi- ble to find a journal that will accept a paper presenting data say on a single linkage. , It has been proposed that those of you who nave linkage data worth publishing but not of sufficient importance to war- rant a separate paper send to the secretory of Maize Genetics Cooperation brief, concisely worded accounts embodying the data and that these short papers be published together under some general heading, but each to be signed by the responsible author. I have been informed that the outgoing editor in chiei of Genetics has approved this suggestion, but it has not been presented to the incoming editor, Dr. Dunn. If the publication of such a collection of brief papers is paid for from sources other than the publishers of Genetics, very prompt publication can be assured. It would seem that the grant of funds made by the Rockefeller Foundation for the support of Maize Genetics Cooperation might be used legitimately for this purpose. Be- fore presenting this proposal to the Rockefeller Foundation for 147 2. decision, I desire an expression of opinion, favorable or un­ f a v o r a b l e , from as many of you as possible. I shall also want indication of how many of you may desire to have papers in­ cluded in such a collection to be published late this winter or early in the spring. II Reports have been received from a few of you who grew in­ bred strains last summer to determine relative resistance to smut and other diseases, general adaptability, etc, I trust that the ethers who received seed of these strains will report soon so that all reports can be tabulated for the next news letter. It is already apparent that no one or two of these strains will be useful in all regions of this country. Since the strains tested the past summer came from only two sources, Dr Hayes and Dr. Wiggans, it seems probable that others of you may have or know of inbred lines better adapted to some regions than any of the strains so far tested. If you will indicate this to me, a further test can doubtless be arranged next sea­ "011, Altho the inbred strain test was started with the hope of finding one or more strains widely resistant to smut, which is a serious drawback to many of the genetic stocks grown by some of us and particularly serious in case of plants injured in collecting sporocyte material for cytological study, the cross­ ing of good inbred strains with genetic stocks may prove very useful in other ways. If one desires to make an accurate com­ parison of segregates in any culture involving even so few as two allelomorphic characters, it is necessary to use relatively large numbers of individuals to make sure that the nine chromo­ some pairs other than the one directly involved in the compari­ son are, on the average, the same in both segregates. When, by the nature of the comparison, one is limited to a few individ­ uals, as might well be the case in certain histological, phys­ iological, or chemical investigations, it becomes essential to employ material with as uniform as possible a background of genes other than those involved in the study. Such material can probably best be obtained by repeated backcrosses of the recessive segregates to the same inbred line. Backcrossing separately to two inbred lines makes it possible later to study the segregates in vigorous material by intercrossing two such backcrossed progenies. In line with this purpose, cresses were made last summer of six dwarf and semidwarf types with two of the inbred strains which did well at Ithaca. This was done to get material for Mrs. Abbe*s (Minnesota) histological and devel­ opmental study of these types. In so far as possible, other^ undesired genes linked with the pair to be studied were involved in the crosses. When in progressive backcrosses these unwanted genes are lost, one can be reasonably sure that a considerable part of the chromosomes carrying the genes to be studied, as well as the other nine pairs, are relatively uniform genetically for both normal and dwarf segregates, Even one or two back­^ crossings should afford material that is much more nearly uni­ form than are most segregating genetic stocks now in use. 148 h i Hand, pollinations of the cooperative material last summer were for the most part highly successful. We shall be able to include a list of these stocks in the next news letter. A list and seed of new stocks which any of you may have nd which have not previously been sent to the secretary are herewith called for. The list should be ready for the next news letter and the seed should be sent as soon as convenient. IV This is also a call for items of interest to be^included in the next news letter. Please include new genes, indications of linkage of new or well known genes, etc. Linkage data might well be included unless you intend to submit them later for in­ dependent publication or for collective publication as proposed in this letter. V ­ Summary ­ 1. Please report promptly on behavior of inbred strains if you grew them and have not yet reported (See II above) Send list and seed of new stocks (III) 3. News items are now due (IV) 4. Indicate (a) whether you do or do not favor the pro­ posed collective publication of short signed articles on link­ age in maize, (b) whether you will probably be able to submit such articles by late winter or early spring, (c) deadline date favored for reception of such articles. 5. All these items (l­1! above) should reach me by December 20, 1935, so that the next news letter can be sent out early in January. (Signed) R. A. Emerson Secretary "pro tern" 149 MAIZE GENETICS COOPERATION NEWS LETTER 10 March A, 1936 Department of Plant Breeding Cornell University Ithaca, N. Y. 150 M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A . N E W Y O R K March k , 193^ To Maize Geneticists This letter contains information from many sources, arranged under the following heads I. Collective publication of linkages. II. General news items. Includes notes on linkage without data, lists of seed stocks, etc. III. Linkage data. IV. Seed stocks received, and those propagated in the Cooperation garden at Ithaca. V. Tests of inbred strains for disease resistance. VI. Special notices. Most of these reports are given almost verbatim but are not put in quotation marks because in numerous instances they have been somewhat abbreviated and sometimes the phraseology has been changed (without, I trust, a change in meaning). Statements enclosed in brackets, Cl , are gratuitous comments by your sec­ retary. I. Collective Publication of Papers on 1 Linkage in Maizen Perhaps the most" important matter presented in this news letter relates to the collective publication of separately headed and signed articles on linkage (see news letters of March 6 and November 30, 1935)• The response from cooperators has been wholly favorable and several have indicated their readiness to contribute to such a series of papers. Dr. Hanson, representative for the natural sciences of the Rockefeller Foundation, has written as follows; "Regarding your request to use a small part of the fund for the publication of brief papers in Genetics, since this seems to you to be merely using a somewhat different mechanism than you originally contemplated for putting this maize material before the geneticists interested, the Foundation will have no objection to a small portion of the funds being used for that purpose. With kind regards, I am Cordially yours, (Signed) Frank Blair Hanson" 151 Dr. Dunn, editor in chief of Genetics, with reference co mir ­proposal, says; , ,, "I see no danger in this so long as we adhere to the ba.sic rule for publication in GENETICS — i.e. soundness, significance and permanent value of the material printed, and so long as we are just as free to accept or refuse such papers as any others. I think the publication of such material should differ as little as possible from other papers published; that is, it should not form a separate department of the journal which would constitute a special privilege and might bring resentment from other groups. I think we shall be able to make satisfactor}/­ arrangements and suggest that when ready, you send in some sample copy which we can use as the basis for settling form, etc. We go to press on February 15th (May Number) and thereafter on the first of each odd numbered month. If an arrangement is made, copy can be printed in two months (plus about five days) from receipt of mss. Sincerely yours, (Signed) L. C. Dunn” See also suggestions by Jones (news letter March 6, 1935? pp• 19 f 20). # Of course, we should not expect to receive preferential treatment from Genetics, and could not expect our papers to be accepted unless they meet the standards set for that periodical. I am anxious to try the plan this spring. It is obvious that we cannot get material ready for the May issue of Genetics. The July issue goes to press May 1 (I assume from Dunn's letter), and manuscripts should be in the editor’s hands some time before that I ask, therefore, that you send such material as you desire to include to reach me not later than March 31. Manuscripts should be typed and ready for publication with­ out change. When new genes are involved, a short, concise des­ cription of the characters differentiated by them might well be included. Well known genes should not requiresuch treatment. Tables should be presented in summary form. Different cultures involving the same kind of data should not be listed separately unless that is essential in order to demonstrate significant differences between them. Of course F2 and backcross data lor coupling and repulsion must be entered separately in the tables. A single frequency distribution may often be displayed in the text to better advantage than in a table. Tables of data should be &nd k­2c 0 are effective in producing a markedly increased frequency of tetraploid sectors in the root­ tips and stem­tips, more mutant sectors being produced in the roots than in tho stems of the same treatment. Negative results were obtained from a study of the persistence in the mature plants of tetraploid sectors induced by heat treatment of the germinating seed. Over y jO plants were included in the experi­ ment and no tetraploid cars or ears with tetraploid sectors, as determined by applying pollen from tetraploid plants to the treated plant and noting the set of seed, were obtained. 4. Heat treatments of diploid corn, barley and einkern in early ombryogeny and in the seedling stage induced an increased frequency of segregating mutant se< dling types differing from the normal either in growth habit or morphology or in the amount of c ill 0 r op hyl 1 d 0 v e 1 opm on t. 5. Inbred stocks of tetraploid maize after four generations of selfing have good vigor, reasonably good uniformity, and in some cases an increase in fertility over the original parental tetraploid stock. Tetraploid strains of commercial yellow corn arc being tested in cooperative bio­chemical and animal assay experiments to determine their vitamin A potency. Since the tetraploid yellow maize endosperm has six doses of Y rather than three as in the normal diploid yellow corn the vitamin A potency may be twice as great in the former as in the latter. 6. The tolerance of dormant seed to heat treatment varied with the moisture content of the seed. Corn and barley seed with 2k per cent moisture was killed with one qQ­minutc treatment at 100° C. With a reduction of moisture content to 9 per cent the seed was not injured by a 30­minutc treatment at 100° C, but after 60 minutes germination was only 30 per cent, and after 2 hours only 10 por cent of the seed germinated. Seeds with 5 Per cent moisture germinated perfectly after 2 hours treatment at 100° C, but were killed after 30 minutes at II50 C. Seeds with 2 per cent moisture, the reduction in moisture content being accomplished by drying approximately 3 weeks at 60° C, germinated well after pO 154 . tes at 11(5° C, but only 10 per cent germinated after 60 rnin­ and 30 minutes at 130° G killed all of the seed. The corn pollings from the sub­lethal dosages at the different moisture Contents were weak and chlorotic, many failing to survive, but the development of normal green color was not similarly altered in the barley seedlings. 7. In further studies on the 3­type chromosomes in maize the number in individual plants has been increased to 32­35> with no "marked decrease in plant vigor but with an appreciable de­ cease in fertility among these extremely high numbered 3­type plants. Both Florida, and Durango teosinte occasionally have 3­ tvpc chromosomes which are morphologically identical with those in maize, and exhibit the same synaptic behavior and breeding relationships. Plants of Florida teosinte with 5 B­type chromo­ somes and plants of Durango with as many as 10­13 have been ob­ tained by inter­crossing plants with lower numbers. From an extensive survey of chromosome morphology in various stocks of̂ maize and teosinte, primarily for the purpose of determining the orinin of the B­type chromosomes, an extremely wide variation in proohase morphology in different stocks has been noted; maize stocks with as many as l ' y i k sizable knobs and others with as few as 1 or 2 have been discovered, also Durango and Florida teosinte stocks with very few and other stocks with numerous knobs. How­ ever, a careful search for a chromosome arm in these diverse stocks similar to or identical with the 3­chromosome has been fruitless thus far. This suggests that the 3­chromosome may be a composite of several parts from different regions of the same or different A­chromosomes. L. F. Randolph 3. Mosaic plants in part heterozygous and in part homo­ zygous for a chromosome 5 deficiency. ­ Breakage in the spindle fiber insertion region of chromosome 5 resulted in two chromo­ somes, one a deficient rod­shaped chromosome and the other its reciprocal, a ring­shaped chromosome, each with an insertion region, the two equivalent genomically to one chromosome 5 (McClintock, Proc. Nat. Acad. Sci., 1932). Two such cases were described. In one case, known as the large deficiency large ring, the ring involved approximately one­sixth of the length cf the chromosome, including the locus of Bmp. In the other case, called the small deficiency small ring, the ring involved about one­twentieth of the length of the chromosome and also included the locus of 3nh . It has been found that the small deficiency can function through the eggs without the small ring being present also. Pollen having the large deficiency plus the large ring­shaped chromosome (the full genomic complement for chromosome 5) can function as well as normal pollen with an intact chromosome o* When two such gametes fuse, an individual having the small deficient chromosome, the large deficient chromosome and the large ring­shaped chromo­ some is produced. As stated in the above publication, loss of the ring­shaped chromosome occurs in some mitotic divisions. In the plants resulting from the described cross, the nuclei and thus cells which arise after such a loss of the ring chromosome will be homozygous deficient for the amount of chromosome repre­ sented by the length of the small deficiency. Such plants should 155 therefore, a mosaic of heterozygous and homozygous deficient +iRsue if cells whose nuclei have undergone the loss of the ring chromosome can continue to propagate themselves. It was known that the heterozygous deficient tissues do not vary noticeably from non­deficient tissues. If, in these plants, the homozygous deficient tissue is viable and if the homozygous deficiency alters the structure of the cell, streaks of altered tissue should be detectable. Streaks of altered tissue were very obvious in the leaves of such plants. A histological study of the nature of the alterations is being conducted by Mrs. Lucy Abbe. From the ap­ pearance of the homozygous deficient tissue it is probable that such tissue would be inviable if not surrounded by normal tissue. The original "double­deficient" plants were obtained by crossing plants having a normal chromosome 5 with bmp, a deficient chromo­ some 5 with no lucus for Bmp and the ring chromosome carrying Bmp. The "double­deficient" plants were all Brnp except one plant which was variegated for Bmp and bmp. The introduction of the bmp locus of the normal chromosome 5 into the deficient chromosome is be­ lieved to have occurred as the result of a non­homelogous cross­ over between the normal and deficient chromosomes with a resulting shift in the position of the deficiency (as described by Stadler in the Amer. Nat., 193^)• 9. Several inversions, two involving sections of chromosome 9 and one involving a section of the long arm of chromosome have been detected and isolated by Miss Creighton and myself. One of the inversions on chromosome 9 should eliminate single cross­overs within the short arm of this chromosome, although the tests have not been completed. 10. Disjunction studies on interchanges have shown that sis­ ter spindle fiber regions do not separate in I, that crossing­ over between the spindle fiber and the break is followed by disjunction of homologous spindle fiber regions, that the passage of two homologous spindle fiber regions to the same pole in I is increased when the crossing­over is decreased, and that whether ^ or 6 types of spores will be formed and their proportions depend upon the relative distances between the spindle fiber regions and the breaks coupled with crossing­over in these regions. Barbara McClintock 11. Data from crosses of Florida toosintc with maize, back­ crossed to maize, showed little or no crossing over in the short arm of chromosome 9* but between wx and v­j , there was from 6 .k f j (Creighton) to Ij­Oy (Allen) of crossing' over. Sylvia M. Allen and Harriet 3. Creighton 12. An inbred strain of yellow dent corn, which, after hav­ ing' been sclfed for nine generations, has been propogated by sib­ crossing or mass pollination for three years, has given rise to two striking mutations, namely, yellow to white endosperm and normal stature to a slender dwarf type. All the white endosperm kernels germinate prematurely. R. G. Wiggans University of Minnesota, St. Paul, Minn, ­ 1 , I have been studying an abnormal tassel type that I pro­ pose to call ramose tassel. It gives some variation in ear type. Some strains show crocked rows and generally a few sterile male 156 fiorets on the tip of the ear. In other cases the upper half of p ear is divided somewhat like ramose­1. In crosses, however, either of these types can be separated from rap with considerable accuracy. Linkage studies of ramose tassel were made last year sing Fg data from crosses with representative genes of the ten croups. ~ linked with nap crp and py in group 3 (py in ;Jr0Up 6] . It has occurred to me that this may be the same factor or an allelomorph of rag reported by Brink but not published. [Brink’s linkage data (Linkage Summary, pp. 4­1, 4­2) give ap~ra2 and rag­Rg 34­$ recombination^ n 2. I note your statement [Li nkage Summary, p. 12j that floury is difficult to classify in many stocks. I have had no difficulty except where some of the virescent seedlings were con­ cerned. I classify commonly over a ground glass with light under­ neath. H. K. Hayes. U. S. Dept. of_ Agric. 3 Cereal Crops & Diseases, Ames, Iowa ­ 1. A branched car was observed in Fg (1923) of the station strain of Reid’s Yellow Lent. It appears similar in all respects to the one described by Kempton as branched silkless, bd. and was reported by Rhoades (Maize letter, November 24­, 1934­) to be allelomorphic to that gene. Fg data involving bd with two other genes show it to belong to group J. [.The data (see III, below) seem to place bd to the right of ij, near 3np. Hadjinov’s data (Linkage Summary, p. 57) give about 36$ recombination between his bd and Bnp. His bd has not been tested with either Bryan’s or Kempt on’s 7) 2. A character similar to Brunson’s cuzcoid was found in Fg of the variety Krug in 1934­. It tasselcd very late but produced no car shoots. It had about 50$ more nodes than normal corn. It apparently is controlled by a single recessive gene. A. A. Bryan3 3. The study of the factor interaction of an and Dt has been continued (sec maize letter of November 24­, 1934­). On the basis of rather extensive counts the ratio of the average number of dots on seeds of ap ap ap Dt Dt dt to the average number of dots on seeds of ap ap ap'Dt Dt dt constitution is 3:2. The ratio for seeds of ap ap ap Dt dt dt to ap apP apP Dt dt dt corv­ stitution is 3:T* Since in the comparisons the Dt gene is held constant while the dosage of ap varies, it is apparent that the effect of increasing the dosage of recessive ap, as indicated by the average number of dots, is an arithmetic one. In reciprocal crosses between two closely related lines (ap ap dt dt x ap ap Dt Dt) the ratio of the average number of dots on seeds of Dt Dt dt to seeds of Dt dt dt constitution was 4­:l. Some data have also been obtained on the number of spots of Dt Dt Dt constitution. These data indicate that the effect of increasing the dosage of Dt may be geometric. 4­. Further study with the chromosome 5 fragment (see maize letter of November 24­, 1934­) has placed the following genes in the long arm of chromosome 5: vg, ys, pr, vpg, v­, and bt. The loci of ag and bmp are in the short arm of chromosome 5* The fragment chromosome, which is composed of the short arm of chro­ mosome 5 anc*­ has a terminal insertion region, occasionally passes 157 te ough_ __th_e p_o_l_l_e_n_. In the progeny of a selfed. fragment plant ^hpre^occurred an individual with the normal complement of 20 c!h^rnopmoossoomeess pplluuss two fragw ment chromosomes. ,In genetic constitu­ tion and appearance this 22 chromosome plant was identical with the secondary trisome found several years ago in which the single supernumerary chromosome was composed of two hort arms of chro­ mnsorne 5 ̂. Pplants having a single ifragmenxt chromosome were studied at'3pachytene.. As reported before, the fragment pairs with the two normal chromosomes p approximately half the cells. It was occasionally observed in those cells where the fragment was un­ paired that the terminal insertion region presented the appearance being split. This observation may have some theoretical im­ portance since some of the prevalent tneories of meiosis assume that the reason the spindle fiber region undergoes a reductional division in the first meiotic anaphase is that the division of the insertion region is delayed to a late pr opnase stage while the split of the chromosome thread occurs in the early prophasc stage*. ^ inbred strain gave in F2 approximately 65$ luteus seedlings (again see maize letter of November 2k, 193*0. The genetic constitution of this line was with about 2 per cent c r o s sing over between the sp and 1 loci. iheso u.10 genoo have boon linked with factors in chromosome 10. They are very close to gi and give about 20 per cent of recombinations with R. The lutcus gene is designated as lg and the small pollen gene as sp2 . Seed available. 6. A triploid individual occurred in a cross of glp x wsp. The constitution of the triploid was dip Glp glp Ws-5 ws­j which suggests that the diploid number of chromosomes was contri­ buted by the pollon parent. 7 . During the harvesting of the fields in tne Iowa Corn Yield Test several oars were found which had, to tne writer, the appearance of triploid cars. Root tip counts Oj. the progu stantiated this hunch. g. Half the plants in a small Fp progeny of an R­g­li s ,ock x Florida tcosinte had narrow leaves, an unusual type of chloro­ phyll striping, and brown midribs. Neitner 01 tne parents showed this character. It seems possible that wo have nere a case ox factor interaction between Zea and Suchlacna genes. Se^cral crosGcs wore made between the R—g— li stock and Florida teosin^e and only one of the Fp progenies showed this new character. 9. In the progeny of^a plant trisomic for chromosome 6 there occurred an individual witn 20 chromosomes plus a fragment composed of the long arm of chromosome 6. The insertion region is apparently terminal. Studies of tne disjunction of the two^ normal chromosomes 6 and the fragment, utilizing the technic of^ McClintock in studying the number of nucleoli in the q u a r t e t s of microspores, showed that in 2.4­̂ > of the eases the fragment cn.ro— mosome wont to one pole and the two normal enromosomos to tne other pole. In the remaining cases the two normal chromosomes underwent disjunction. 10. Studies of some of the Iowa inbred lines showed that m those inbreds which are poor pollen producers there was a con­ siderable number of unpaired chromosomes at Metaphase I._ Those unpaired chromosomes undoubtedly cause some 01 the sterility 158 p j_n these lines. Fertile inbred lines showed fewer univalent pV'ornosomes. In the "sterile" inbreds the pairing pachytene was rfect and the unpaired homologous chromosomes showed at diakin­ osis an orientation to each other ^becauisrep nof this earlier associa.­ 1 "*1 1, in a selfed line homozygous for all the dominant aleurone fac to rs there occurred seeds with colorless areas of varying size (Anderson had a similar character several years ago. He called it «*Sr;Id" aleurone.) The explanation for the appearance of colorless ‘paa in this line is due to the failure of formation of the aleurone layer. 12. New stocks: Tp~glp~vr­ra ai­lg2 Dt ap­na­tsij. Dt pr­bmp­ap (pr o bably) 13. Studies with Pvv and sm indicate that intensity of sal­ mon color in silks depends upon amount of variegation on the ear. The silks have a uniform color, not variegated. pit. Golden­1, gp, though not identifiable by external appear­ ance, can be classified accurately in the seedling stage by cut­ ting off the seedling stalk iust above the ground. Golden­1 seed­ lings have a distinct golden'color in cross section while non­ p­olden ones are clearly green. M. II. Rhoades Agr»l Experiment Station, New Haven, Conn. ­ 17 We are informed by Eye ter that his opacrui is the same as our op. [Eystcr reported in chrom. 2/ 2. A maternal stripe has­been obtained from a series of Sweepstakes inbreds. It is more vigorous than those obtained by Demerec and Anderson. ...... 3. The dwarf reported in maize letter of November 24, 1934 is not dp. It segregates well and is viable but never produces an ear or even pollen at New Haven. Seed available. 4­. The adherent reported in the same news letter is not adp. Viability good. <5. Seed of a stock of trisornic chromosome "r is available, Op + + 6. Fp, 7S& individuals, of -7 gave recombination per­ + glp centages as follows:­ o^ ­ glp 27, o2 ­ i i 37. Another Fp, 323 seedlings, of ^2 , gave 22$ crossing­ T glp over. Backcross data, 4­33 plants, give 1.7$ crossing­over between op and rap. These data indicate that op is to the left of . 7 . We apparently have two complementary factor pairs for yellow endosperm. I have tentatively designated one of them Yjp and the other It (intensifier), I have only one stock of Yg Yg it it, but It is carried by several white stocks, in fact, all so far tested except one a­tester. It might be an allelomorph of A. Fp seed of the cross Yg Yij. it i t x yg yjp It It is all yellow. The Fp ears segregate fairly well into a 9*7 ratio for yellow and white, showing several intensities of yellow. I do not think the stock of Yg Yip i t it i s the same as Yp. It is 159 h lighter in color and shows segregation well only in very flinty corneous stocks. The intensifier stocks, yif yi| It It, aolis­on iinn­uttejin sifyy the yellow color of Ypx. Ralph Singleton TT­.î prsitv of Florida^ Gainesville, Fla. ­ —­­­­ T7'k few years ago an inbred ear segregat n ed sharp li yi 0ye :l 1l ;ow and pale yellow endosperm. Th 10 e 0 pale seeds producn eP di .o st $ white seedlings and the others produced near o lr y e o an l ls eedlings. Brunson reported something sim ° ilar , I 2 t. h inA k .first year inbred ear of Cuban Yellow Flint se q gh ra er gnl av t' er ded and green seedlings and a range of intensity e n od fo s yp ee lrm l. o w The seeds were arranged in order of endosperm color a nd the darker 3/U­ planted separately from the ligh t th ei rs 1c /l na .s sif Oni cation crossovers with anthocyanin were abo m uh tc 2s 0t $o .c k was grown through two more generations with o f s ec la er cs tig oi nv ^i ng lesser crossing over and the crossovers red a ub co eu dt t1 o0 %. The reduction was attributed to s se eg lr e eg ca tt ii oo nn for sharper and more accurate classification of endosper T mh e c oa ln ot rh .o cyanin difference was indicated at the R locus by out­ crosses to Cornell aleurone testers. Fred H. Hull California Institute of 1 Technology, Pasadena­ ^­ J­ 3­ al, j jD \a t ­a on "striate and interchanges place sr oetween P and br. 2. Summary of map position 1 s 3 of 9 interchanges in chro moso ̂ me sa nd 10." Part of this is a repetition of what I sent last year. Chrom. 1 ­ " Left of P. An undescribed 1­6 interchange gave the order T­P­sr with 6$ crossing over between T and P. Near P, order uncertain, l­2b, l~9c.^ Between P and br l­3a, l­6b, 1­5°> l~9a * Near br 1— 3d, 1­7°, 1­7° > l~9b> l­10a. Between br and bm2 l~5a > 1~^ > l~7d. Chrom. 3 ­ Betwecn a and na 2~3d, 3~5C > 3~5b. Nearer tsi| 1—3a > 2— 3b, 3~7a » 3~0a, 3~*9a > ̂ 3~* P 1r 0ob aa ,b 3l ~y ^ cb •e yond tsip but order uncertain J—lCa., 2— J»c, l­3d. Beyond ts^ (27.2$) 3­7b. Chrom. 9 ­ all tested are beyond waxy. crossing, over No. of backcross plants l­9a . 239 l­9b 3 505 l~9c 125..7* 2 237­9a 2 39 0.7 pop­ b 7­5 622> 3­9a 3.6 60S 4­9a 25.1 k-26 (2 groups of data 31*0 and 1 1 .6) U 9 b 3.1 193 6­9a 9.5 6106­ 9b 3.7 731 160 6­9b 35 «o l4l (data ir­ regular ) 9 1̂0 about 3*5 (estimated from combined wx~T and T­R intervals) C hr onu 10 ­ crossing over with golden­1 (left of gg) § crossing_over No of plants 1­ 10 a 15.0 "“"137" 2­ 10 6 . 2 go 3­10a 15. 4 4£l 3­10b 20.0 320 3­ 10c 7 . 0 346 6 -1 0 9.7 642 g­lOa 1 7 . 0 427 g­lOb 21^2. 310 g­lOc .6 7 335 4­ 10(nbe ar g^, order uncertain) 9-10 (Right of R) 3. Summary of map locations of interchanges on chromosome 9 Combined data of Clokey and Anderson. Near B 2—6b, 2­9a. _ Between B and vij. l­2b, 2~3c, 2­6, 2­3d, 2­10, 2­4d, 2­7b , 2­9b. Far right of B but not yet tested with vj, 2­7c. Near vg 2­4a, 2­4b, 2~5b, 2­7a, 2~7b. Beyond vh 2-4c (vh - T = 35)• E. G. Anderson University of Buenos Aires, Buenos Aires, Argentina ­ 1. In Garrapata corn from the Province of Salta in Argen­ tina and from Bolivia, spotted aleurone is due to a dominant r modifier giving mottled aleurone. Mottled x a and c testers gives self color Mottled x r testers gives mottled F1 , but in F2 some colorless kernels appear. The modifier is inde­ pendent from pr and from a and c but seems to be linked with r. The r modifier is designated Mr. The backcross: r Mr Fr/r mr pr x r mr pr gave Mottled purple 66 Mottled red 59 White 126 251 Oir has been used by Xvakan for midrib (Linkage Summary, p, 13) but the stock has been lost. Sceus sent loor like "stip— pled'", which is cither an allelomorph of r or very closely linked with it]) 2. Six "glossies" wore obtained from selfcd Amargo and otner varieties. They are designated temporarily by the following sym­ gx33a Sarne as gig e133b Different from gl1} gl2 , S13? and ggif­a From sample of floury corn from Humahuaca (Jujuy, Argentina), different from gig and gig. 161 gl­zipD From a yellow flint; being tested with other ̂ glossies. gl^c From the Amargo variety; different from gig. 3, A oarren­stalk type was found in the stock of gl îpc. If. A liguleless stock was found in Amargo corn. A planting * 100 selfed seeds gave 56 green and 2$ lethal white leaf base seedlings. Of the normal green plants that lived to the age^of three months, 285 had normal and 20 had liguleless leaves. This is at present designated lgjl+a. 5. a selfed plant of Amargo produced, from 50 seeds, 22 normal plants and 7 dwarf plants with bifid leaves and the midrib prolonged into a conspicuous awn, like the flowering glume of Aveneac. The character is called aristifolia and its genetic symbol is given as af. The aristifolia character is not known in grassesJ so far as I am aware, except in a small genus of Mexican grasses (jouvea), the taxonomic position of which is uncertain. 6. Lazy, laxl̂ a, appeared in the progeny of a selfed plant of the variety, "Maiz Canario de 8> filas", which consisted of a7 normal and 15 lazy plants. Has been crossed with su glj. 7 . Siamcnsis, sn, is a recessive character of variable ex­ pression obtained from an Amargo strain. Of the double seedlings, the "paracito twin" aborts early in some instances, leaving nor­ mal appearing individuals. A homozygous strain of sn exhibited the following types: Seedlings with marked duplications ­ 12 Seedlings with different abnormalities ­ 32 Seedling normal ­ 1. Male sterilcs: A male sterile, rns­?­̂ , from a strain of maize from Tabacol (Salta, Argentina) gives''a sharp 3:1 segrega­ tion. Another, ms 3]^, from Kumahuaca (jujuy, Argentina) is linked with aleurone color. The stock is segregating for R r. 9. Tassel seed, ts­^p, has been found in a yellow flint from San Luis, Argentina. ' f 10. Germless­ seeds, from a selfed car of Piamontes, a flint corn, had 112 normal"and 30 germless kernels. 11. Silky, si­,7,,, came from the same Piamontes strains. S. Korovitz Instituto Agronomico de Campinas, Sao Paulo, Brazil ­ Attention IF called to a bulletin from Brazil: Effcitos da primeira autofecundacao em tres variedades dc milho. Technical bulletin #19, p. 19, with 37 photographic illustrations (five colored plates). Published in Portuguese with an abstract in English, as follows: 1 The Genetics Department of the Instituto Agronomic© started in 1932 a large maize breeding project based on the pro­ duction of pure linos to be used for hybrid seed production. Over 3000 vigorous plants of 3 main commercial varieties were self­fertilized and part of the seeds of 1S12 selected inbred oars was planted out for further selfing. In this paper the author describes some of the more prominent variations found among the selfed oars and also in the progenies. Most of these off­types arc compared with similar variations worked out by American geneticists. The variations described hero are: (1) premature germination of the seeds on the ears; 2) several cases 162 Of d e f e c t i v e endosperm; 3) endosperm color (yellow­white); 4) ,Liv endosperm; 5) Aleurone colors; 6) Pericarp colors; 7) white ­Ldlinys; 3) yellow seedlings; 9) zebra striped seedlings; v 1ir 0e )s cent seedlings; 1 1 ) pale green seedlings; 12) zebra striped leaves* 13) several kinds of striped leaves; Id) oily spots; 15) c­everal kinds of dwarfs; 16) narrow leaves; 1 7 ) crinkly leaves; {$) ramosa (?); 19) rolled leaves; 20) ragged 2 2 (?); 21) branched j,. ) several kinds of abnormal sex distribution: male and fe­ nale plants, extreme cases of ’tassel­seed*, etc. — a u It th o ir s’ s the^ intention to exchange seeds of his genetic material with American geneticists in order that some of the supposed new vari­ ations may be conveniently worked out and their genes be located in the maize linkage groups”. C. A. Krug University of Zagreb. Jugoslavia ­ — ' I, 'Attention is called to a recent paper dealing with the inheritance of number of kernel rows in maize (Tavcar, Alois ­ Beitrag zur Vererbung der Kornreihenanzahl an Maiskolben.^ Zeit­ s c h r i f t fllr Ziichtung, P flanzenzuchtung, 2 0 : 364­376. 1935)* A ip­rowed type is described and its genotype is assumed to be Rwg Rw # Crosses of i­rowed with g­rowed forms exhibit monohybrid Fp and backcross ratios. To the genes differentiating these two forms are assigned the symbols Rw2 rwp. 4­row = Rwp Rw1 rw2 rw2 ; row = Rwp Rwp Rw2 Rw 2. Rw ̂ and Rw2 are inherited independently of each other and of P and Yp. [Since, on the author’s assump­ tion, Rw1 is homozygous in both the 4—rowed and S­rowed types used in these crosses, no evidence is presented for the independ­ ence of RWp from Rw2 , P and Yp. Of course Rwp could be used as a symbol for the residual genotype of a 4­rowed form, but there seems no more need for such a symbol here than in many other casesj 2. Four­rowed ears have two rows of kernels on either side of the cob, the two pairs of rows being separated by smooth areas (rachis without paleae). It is necessary to distinguish between palea and rachis color as well as between these and pericarp color, all of which belong to the P allelomorphic series. Ten Genotype Pericarp Palea Rachis (with A) color color color prrr red red red prrw n ti white prwr 1 white red prv/w it 1 white pwrr colorless red red pwrw it it white pwwr it pwww 1 wh1ite red: white porr or1ange red. rodpoww white white An account of this series will probably be published in Zeits­ chrift fur induktive Abstammungs ­ u. Vcrerbungslehre. A. Tavcar 163 I k . John Tnnes_.Horticultural Institution, Merton Park, London ­ '­­­ X. There is™pronounced indication of linkage between a crene for fasciated ear and white endosperm. 2. In a cross between fasciated­cherry­japonica and golden, the majority of the Fx plants were not­gclden not­fasciated but were japonica. Fp segregation was normal for the first genes but ­ave $9 japonica in a total of 139 plants, When japonica was crossed with dwarf­;; all Fp plants were green, not japonica. 3. In a cross between a line with coloured aleurone and rr lines, four alleles of R could be distinguished, by their different effects on aleurone colour. Otherwise the plants were of the con­ stitution AA CC bb PI PI. At least one of the R alleles involved seems to be a cherry allele. Two alleles were the normals, at present designated R and r. A third may be identical with the allele recently discovered by Rhoades, and designated here r 1. The fourth is a very weak dominant called R*. The four heterozy­ gotes when selfed gave Rr 25foc olourless Rr* 3 5# " R*r 50# » R*r* mostly 66fc, in one case 75% colourless It seems possible to obtain colourless R* homozygotes by selec­ tion of modifiers. The ratios 63:1 after selling and 1:7 after hackcrossing seem to indicate the presence of at least three complementary recessive modifiers. 4. The intensity of aleurone colour in the crosses mention­ ed under (3) depends upon two complementary modifiers giving 9 deep to 7 pale after selling. 5. A large set of data was analysed with the help of effi­ cient statistical methods in order to see how many ratios were disturbed by linked genes for pollen tube competition. Indica­ tions of such competition have been found in connection with the following segregations: purple­1 and brittlc­1 (see 6 below) Brieger deep and pale aleurone ” yellow­white endosperm Tidbury deep­pale yellow endosperm " c and sh Tseng. 6. The distance between prx and bt­j_ has been found to be 17.5$. The gametophyte factor gap is located between prx and btp about 12.3 units from prx and k ,7 units from btg. The amount of elimination in Ga/ga heterozygotes has been found to vary and has been studied in both typos of heterozygotos, i.e. and Prl ga2 Btl prx gap btp P*1 Gap btx The data vary round the moans 15^ and kofo instead of the ex­ pected 50$. 7 . Random pollination of unprotected plants has been found to be of rare occurrence in the experimental plots both at Berlin and Merton. Sclfing predominated if unrelated lines which, how­ ever, flowered nearly simultaneously, were inturplanted. Random pollination was found only if the plants wore nearly identical in composition. 164 2>. Experiments on earliness and yield were started in order to find types well suited to the English climate. A number of varieties were tested in randomised blocks. The plants were sown in three lots. The variation within each lot was very small. Plants "sown on April 17th and planted out in May were far the slowest, those sown on May 21st and planted out on June lH­th were cuicker and needed about two weeks less. Plants sown in the field on June 5th gained another seven days. The differences between the varieties were partly very significant. I am convinced that part of the failure in the cultivation of rnaize in northern Europe is due to the fact that the seeds are sown too early and kept too long in pots. 9. A fairly large coupling Fp of C Sh/c sh and I Sh/C sh has been produced (9053 grains in the first and 7226 in the second case) to see whether there is any significant difference between the recombination values. All the data from the individual ears as well as the totals form a homogeneous sample around the common mean of 5.1$. A backeross for C Sh/c sh gave 4­.3f in 66k&. The difference between all Fp’s and the backcrosses is .just over twice the error. Experiments will be made to test reciprocal backcrosses. F. 0. Brieger Honan University, _Kaifeng, Honan, China ­ 1 . a white waxy strain of maize from the province of Sze­ chuan was crossed to al y PI, white seeded of course. The F]_*s were all yellow seeded. Fp gave lH-6 yellow and t~[ white, a case of complementary factors. Linkage tests are in progress. 2. From selfed strains of corn collected from Honan province, one ear was found to have prematurely germinated seeds that seem to be linked with y. On selfing again one ear was found t 13 o9 have yellow and 59 white seeds. All the white seeds had germinated on the cob. This may be a case of complete linkage. Progress is being made to ascertain this. III. Linkage Data 1. Four­point tests, group 2. I. T. Clokey + + + + Igl S12 3 VH­ 0 1 2 3 1 - 2 1-3 2-3 1- 2-3 12H- 136 HO 29 5S H-2 101 31 S0 3 1 16 09 15 19 17 13 16 1 5 l&k 11 2 6 29 6 732 9 13.351 25.if, 1.556 3.6f H-.of O.Sf l £ l ~ g l 2 15«3$> g lg - B 1 9 . 6% B-vij. 3 3 . 5 f 2. Trisomic and backcross tests, group 2, involving albes­ cent, liguleless­1, and yellow endosperm. H. S. Perry Fp data from the cross of #2 trisome carrying Igl X that al is in chromos orne 2. d1° d + + + !gl al + al !&1 al 21 61 !gl lH­ 0 = 156 H-90 H-2 ­ 39 9H­7 0 = 5Z2 ­ 7 2 Total — — ­ 735 — ­ 8.3 165 The suggestion of close linkage between al and lg^ seems to be confirmed by a diploid Fp progeny, as follows: 1o + + + lgx al + al lgx !gi al 101 51 4­3 0 195 ­ 26. 22.1 Per cent crossing overcly. Fp_ progenies involving­ Yx and al have indicated close linkage between these two genes. Backcross counts confirm this linkage, as follows: Yellow Not yellow Al al Al al 186 0 0 169 Two seedlings from seeds with yellow endosperm and one non­•yellow, are still too small to classify. 3. Two­point tests, group 7. A. A. Bryan X Y xy Xy xY xy Bd Gl­i RS go1! 254 268 53 = 1379 Bd u 1 RS g06 252 282 39 - = 1379 G11 ij cs 1030 42 58 249 = 1379 ­ 1 6$ [All three genes involved in the same F2 ciiltur es .1 4. Three­point tests , group 7. 0 1 2 1-2 + + 14­8 133 l o 13 16 9 3 _ °lE 281 31 3 ­ 340 K. M. Rnoad.es v5 eii + 9.1# 7 % 0.9$ + + + 337 4-23 23 113 104 3 , 17 16 10 3 217 =1015 I. w. Clokeyra 1!B1! ij 3­3$ 21.4fo 0,4$ 1255 1281 70 44 24 4i 2 0 + + ­t­ 254-0 114 65 2 -2721 A. C. Fraser v5 ral S1! 4.2$ 2.4 $ 0.1$ + in + 15"5 1537 153 36 143 102 57 4o3122 + 1S9 245 97 -3653 A. C. Fraser v5 e1! 5-2$ 6. Tt> -O • T{ V/­ 5. Four­point test, group 7* I. W. Clokey EfcZa_+ + + + rax glx ij 0 1 2 3 1­2 2 11 ­6 3 2­ 3 210 222 5 1­2 17 ­ 325 40 0 0 1 0 1 0 0 0 432 lg 22 65 0 1 1 0 539 3.3$ 4.1$ 12.1$ 0.2$ 0.2$ T—rax 3.5$, ra j-g p 4.3$, 12.+$ Normal and seaisterile (T) plants considered separately: Normal - T-rap ra-i-gli 5• 2$, glp-ij 13-6% Seraisterile ­ " 1.2$, " 2.5$, " 11.1$. The large difference in per cent of crossing over in the two cases is unexplained. 166 6 . Three­•point test, group 1 0 . V. Rhoades 0 1 2 1­2 106) 10 7 J k 6S 20 16 9 S RE_ + +__ 2 1 5 1^2 + 36 17’gi r 3 ̂ .6# O . Oyo 7 . Linkage Data for Chocolate, group 2. (?) Ch V C B 71 66 ­̂2 76 255 ^2̂ which did not germinate. Glossies 1, 2, 3, 6, 7, 9; glc, no germination, # too late to ripen. Hadjinov’s glossies 3, 5, 6, 7, 10 (H3 = ­lb, H6 = gig, H10 = gly, see II above); Hg, all normal seedlings, supposed to be +/gl but some certainly homozygous normal. Hadjinov^s Rsp, rsp, at, bd, cr^, bs?, vb (variable brachytic). , . . . . . ... v Perry’s Yx and yx, m various combinations with Yi yp, pi pi, Al al. Brunson’s pale yellow endosperm, Wiggans’ brittle stalk. Segregating cultures from Wp Wp x Ap b PI py su. Plant colors:­ Ap 3 PI, ap^ B PI, ap B pi, ap b PI, ap b pi. Tester stocks Group 1. ­ P­p fp bmp, P­p br fp bmp, F~p br fp anp, p sr anp bmp, P­p gsp bmp, p as. Group 2. ­ lgp gl2 B b vjp, lgp gl2 tSp, sb, al. Group 3• — SLp nap ts]p, dp3, dprn, a Rg. Group k , ­ la su Tu tu gly. Group 5* “ ysi bmp prp vp, Ap ap bt bv prp, bmp bt prp, bv prp vp. Group 6. ­ Yp PI sm py, Yp pi (zgj?), po y. Group 7. ­ vpr rap glp, rap glp ij, v^ glp Bup. Group g. ­ jp, msg. Group 9* ~ c sh wx vp, ygp c sh wx. Group 10.­ nip gp R, r zb^, dy, li gp Rr. Multiple testers ts2 bm2 lgp b sup Ap nap crp prp yp pi in jp C Rt. bmp lgp b Al sup prp yp pi In Bnp jp c Rg. Pvv Ap su prp yp in c sh wx Rg. Ap Ap Pr pr C­sh­wx gp­R­r. Ap Ap 3­lgp Y­y­Pl Su— su— Tu— tu. Other stocks previously listed are, for the most part, still available. New seed stocks listed under general news items (ll) in this letter but which have not been sent for the Cooperation col­ lection, should be received as long as possible before planting time (May 15). V , Tests of Inbred Strains for Disease Resistance Last spring seed of five inbreds furnished by Professor Kayes and eight by Professor Wiggans were sent to eight coopera­ tors in various parts of this country. All these strains were supposed to be more or less resistant to smut. Some of them were shown to be less smut resistant than expected, several proved very 168 s u s c e p t ib le to bacterial wilt (Stewart’s disease) and a few sus­ ceptible to rust. 1 • Smut. I 'have attempted to present a summary of the observations on smut in tabular form, below:­ _Pe3?_cGrib_smutted plants Mor­ 3034. No. St. gan­ New Ith­ cu l tu re years Paul Arnes, town, Haven, aca, Aver- _Npj__ Variety selfed Minn. la. W.Va. Conn. N.Y. _ M e S64 Golden Bantam 7 10.1+ 0 0 36.4­ 0 9.^ S42 Northwestern 9 6.0 5.0 0 0 4.0 3.0 Dent 070-34 Minnesota 13 5 0 ­ ­ 0 — S2S>3 Rustler 5 10.3 0 0 0 4.0 2.9 086­34 Rustler 6 0 0 0 0 0 0 206 Learning 9 0 0 3.0 0 2.0 1.0 20$ U . S . 204­ 13 6.5 17 .1 30.0 93.7 67.0 42.9 209 Bloody Butcher ii 31.6 S.5 0 i$.7 4.0 12.6 210 Oil Dent 9 1H-.3 3.$ 3.0 -1 2.0 6.07 211 West Branch ? 7.5 0 0 14.3 0 4.4 212 Silver King 14 31.0 2.3 0 21.1 0 10.9 213 Onondaga 12 92.9 j+2.9 0 15.4 0 30.2 White Dent 214­ Dutton's Flint 12 0 3.0 0 0 0 0,6 Minnesota cultures grown under smut­epidemic conditions. Longfellow variety had 65.6$ smut. H. K, Hayes. Iowa season excellent for testing smut resistance; smut infection in general was one of the heaviest in several years. A. A. Bryan, , ^ West Virginia check variety showed smut. C. Burnham* Notes of smut infection ­ Line C$6­34, no smut reported; 214­, little smut at Ames, la. only; 206, light smut at Morgantown, W. Va. and Ithaca, N.Y.; S2$3, light smut at St. Paul, Minn, and Ithaca, N.Y. only; 342, light smut at St. Paul, Morgantown, and Ithaca; 211, some smut at St. Paul and New Haven. Line 20$, showed medium to high percentages of smut in­ fection in most tests; at Morgantown, New Haven, and Ithaca, smut with one exception limited to light tassel infection, but at Ames five ears were smutted. Lines 212 and 213, showed heavy ear­smut infection in some tests. Line C70­3‘+> little to no germination in all tests. 2. Rust. Pasadena, Calif. Little smut in 1935? none on strains in test. Lines 20$ and 211 very badly rusted; 209 moderately badly rusted; 210, 212, and 213 lightly rusted; 206 and 2l4 free from/rust and easily the most desirable for this locality. E. 0. Anderson. 169 Ithaca, N. Y. Lines 3^2 and 211 some rust; 203 much ruSt but too late to injure plants very seriously. There is o0ne’rust present every year at Ithaca, but it usually comes too late to be a serious disease. During two widely separated sea­ sons however, when rust had been introduced inadvertently with seedlings transplanted from the greenhouse early in summer, a very severe epidemic occurred. Many of the more susceptible stocks were killed before flowering time. If conditions should arise by which early infection were brought about, rust would be our most serious disease. R. A. Emerson. New Haven, Conn. "Apparently one of our inbreds, Con­ necticut 2, an inbred out of the Whipple variety of sweet corn, is completely susceptible to rust. We had no rust here during the years that we were inbreeding Whipples from 1925 to 1923. Sometime later, I think in 1929 or 1930, we noticed considerable rust on this one inbred. Aside from rust Connecticut 2 has proved to be our best Whipple inbred and the one we are using in a great many crosses. It is used as the pollen parent and is never damaged so much that it will not make sufficient pollen. It always makes a good crop of seed when planted early. Last year the Eastern States Farmers’ Exchange at Springfield, Mass, planted about an acre of Connecticut 2 for increase. They planted this late in order to avoid contamination from the pollen of sweet corn growing near by. This field of Connecticut 2 was so badly dam­ aged that it did not make a single ear. I am doing some conver­ gent improvement on this inbred and using Rhoades method of in­ oculating the seedlings so I can get a similar inbred resistant to wilt." Of the inbreds in the cooperative test the only one seriously affected by rust was 203 in which about 30$ of the leaf area was covered by rust pustules. Somewhat susceptible strains were, in order of susceptibility: 211, 30$; 209, 20$; 206, 213, and S2S3, 10$, the latter had a few scattered pustules on the leaves of all the plants, W, Ralph Singleton. 3• Bacterial blight (Stewart’s disease). Morgantown, W. Va, Lines and 209 very susceptible to wilt; C36 and S^2 poor plants, wilt (?) susceptible. Chas. Burnham, Washington, D.C. At Arlington Farm, resistance to bac­ terial wilt is of much greater importance than smut resistance* We seem to have universally heavy infections of wilt and suscep­ tible lines are almost completely wiped out. Such was the case this season. Dr* Wiggans’ lines 206, 203, and 210 were outstand­ ingly the most resistant. Merle T. Jenkins. Lodging. V/ashington, D.C. Lines 206, 203, and 210 looked better than everything else until late in the season. In the heavy storm we had in September, 206 and 210 lodged somewhat, whereas 203 remained erect. Merle T. Jenkins, Morgantown, W. Va, Lines S233 and 211 no lodging; 206, 203, and 21Ji some lodging; 210 and 212 badly lodged, Chas,Burnham, Ames, Iowa. Lodging recorded by grade: 1 = little or none, and 5 very much lodging. Roots and stalks noted separately to determine whether lodging due to weak roots or weak stalks. 170 Lodging grade Lodging grade Line Roots Stalks Line Roots Stalks 206 3 3 21S 2 K 203 2 214­ 2 2—1/2 209 1- 1/2 3- 1/2 Sl+2 2 2 210 3- 1/2 2- 1/2 S5J+ 2 3 211 2- 1/2 2 3283 2 2 212 3 3 CS6­3^ 2 1 A. A. Bryan. 5* Firing. Ames. Line 209, "top leaves burned badly just prior to tasseling. A. A. Bryan. St. Paul. Line 213, some firing; 209, upper leaves rath­ er heavily fired. H. K. Hayes. 6. Ear notes. Arnes. Line Seed set Ouali t y Line Seed set Quality poor poor 2 0 9 excellent fair S 4 2 fair good 210 good good S 2 S 3 fair good 211 good good C 3 6 - 3 1! fair fair 212 poor fair 2 0 6 good fair 2 1 3 fair poor 2 0 3 good fair 2 1 4 - very poor poor A • A • Br yan. St. Paul. Line 211, rather undesirable ears at harvest. H. K. Hayes. Ithaca. Line Ears Line Ears S5? * good 209 good S4­2 good 210 poor S2S3 good 211 good 086­3^ fair 212 good 206 fair 2!3 fair 203 poor 214­ good Obviously these inbreds differ widely in ability to produce sound and well filled ears at Ames and Ithaca. R. A. Emerson. 7 * Summary. The" lines most generally resistant to smut are, in order of greatest resistance:­ 036­3*+> 2l4, 206, 3233, 342, 211. Line 203 showed the highest percentage of smut, but in most instances the infection was light and in the tassel only. In rust susceptibility, line 203 showed the most infec­ tion, 209 and 211 much rust, and 206, 210, 212, 213, S^2, and S293 some rust. Bacterial blight was most injurious to lines S54, 209, C36, and Ŝ ­2. Lines 206, 203, and 210 were most resistant. At both Ames and St. Paul, line 209 showed bad_firing. In set of seed, quality of ear, amount of lodging, there was little uniformity. 171 The following comments are of interest:­ Line 211, "excellent". A. A. Bryan, Ames. Under Arlington Farm conditions, I don’t think there is any question but that 20$ is by far the best line of the whole lot. M. T. Jenkins. (Lines 206 and 210 were good except for lodging!) The starred lines £206, 200, 211, 21^7 I con­ sider good enough for use in crosses with genetic testers. C. R. Burnham* My choice of these lines would be about as fol­ lows, starting with the best: 214­, 206, 210, 213, 211, 200, 212! E. 0. Anderson. Line 200, very nice strain, vigorous. Lines S42, S203, 206, 210, 211, 212, 2lU­, desirable types. C$6—34­ fair, 209 and 213 undesirable. H. K. Hayes. From all these comments, it would seem that lines 206, 210, 211, 214­ have rather wide adaptability and that, where rust and smut are not troublesome, line 200 may prove satisfactory. Sprague, however, reports that at Columbia, Mo., none of the lines have value. 0. Some cooperators have indicated a willingness to test these lines further and to include some of their own. Any of you, whether or not you helped in the test in 1935> who are will­ ing to conduct a test in 1936, will be furnished seed in so far as it is available or can be obtained. If any of you have other inbred strains, thought to be highly resistant to diseases and which might be adapted to a relatively wide range of climatic conditions, I shall be glad to arrange for tests. We shall prob­ ably be unable, however, to handle any large number of strains. VI• Special Notices 1, Manuscripts for inclusion in the proposed collective publication of papers on Linkage in Maize must reach me not later than March y i . (See I, above). Some of the data included in this news letter might well form the basis of short papers. 2, New seed stocks should be received at an early date ­ certainly by May 1 ­ so that plans can be made for their multi­ plication in the Cooperation garden. 3* Those having disease resistant inbred strains of possi­ bly wide adaptability which they desire to have tested this year should indicate the fact at once and send seed by April 1. Those willing to cooperate in making the tests will please communicate with me at once. R. A. Emerson, Secretary 172 ma ize "g e ne t ic s c o o pe r a t io n NEWS LETTER 11 March 23, 1937 Department of Plant Ereeding Cornell University Ithaca, N. Y. 173 M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A , N E W Y O R K November c l , 19S6 To Maize Geneticists Contributions of material for the Maize Genetics Cooperation le t ter are hereby requested. These should include anything that you think . . i l l be of value to other maize geneticists. The deadline is January 15. Seed stocks of many of the genes reported have never been sent to the Co*-op to be kept on f i l e for use by other cooperators. This winter a special e f fo r t w i l l be made to bring this collection up to date. Your prompt cooperation w i l l be very much appre- ciated Sincerely yours, Deraid Langham Secretary 174 IJ o l / / M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A , N E W Y O R K March 23, 1937 To y[dii.zB Geneticists; The information in this le t ter was contributed by a number of individuals, and has been organised into the following divisions: I. General news items. I I . Collective publication of linkages. I I I . Seed stocks grown in 193 -̂ IV. Seed stocks received for propagation in 1937* V. List of genes not in Co-op. VI. Tests of inbred strains for disease resistance. Most of these reports are given almost verbatim but are not put in quotation marks because in numerous instances they have been some- what condensed. I • General News Items Maize Genetics Cooperation, Ithaca, N. Y. - 1. Backcross data show that Hadjinov’ s barren stalk (bax ) is allelomorphic to ba2- 2. Seed received from L. C. Raymond, Quebec, labelled "Sweet Brittle", produced plants with b r i t t le stalks and. leaves. These plants differed from b r i t t le stalk (bkx* Wiggans, unpub.) in that they were normal size, and greenhouse tests show that "Sweet Britt le " and bkx 300e n0-t a l le les. 3. Backcross data show that Hadjinov’ s branched silkless (bdx ) is allelomorphic to Kempton's bdx (chrom, 7)* D. G« Langham Cornell University , Ithaca, N. Y. - 1. Data sent by Anderson, with supplementary data of mine, show that j3r (chrom. 1) is to the le f t of P, rather than between P and br as previously announced, and suggest that tS2 is to the right of P. The following table includes the available data from three-point backcrosses: genotype 0 1 2 1 ,2 Total Author p + br 2b2 71 10s 2S bbs Anderson + Tl-5b + 1 5 .^ 0 z b . Ho 6 . 2 $ p + br 195 60 5« + Tl-5c + I S . 1 $ 1 1 . % 519. l 1„o 332 Anderson + + Tl-5b 178 S9 S8 2 0 375 Anderson sr P + 2 3 . 7 % 23 • % 5-3 $ 175 genotype 0 1 2 1,2 Total Author + + Tl-5c 116 6k 36 lk 230 Anderson S P + 27.956 15.756 6. + + Tl-9a 80 21 39 6 Anderson sr P + 50 17 lk 1 Ernerson 130 32 _ 53 7 22g 16.756 23.3% 3.156 + + Tl~9c 97 2k 5 3 129 Emerson sr r + 18.6% 3.956 2.356 P ts.2....+ _ 97 1 IS 0 116 Emerson + + Tl-9o 0.9% 15.556 P + Tl-10b 232 3 kl 0 276 Emerson + tSg + p t s 2 + 169 2 29 0 200 Emerson r + Tl-10b 1)01 5 70 0 '476 i.rfb i 4.756 There is some question about the locus of what is; here designated Tl-10b. I f i t is between P and br as previously announced, then ts9 must be to the right of P. I t is certain that sr is to the le f t o f1- P, thus adding about 25 units to the length of the known linkage map of chrom. 1 and making i t now approximately 150 units. R. A. Emerson 2. Piebald (pbx), found in Emerson ' s cultures, seedlings and plants with large, indefinite patches of white and yellow. Classifi- cation good, v iab i l i ty fa ir . Chrom. 6. Linkage data from F2 crosses Genes Phase XY _Xy xY xy Total % recomb. h CS 50 ^0 122 61k 15.5 PI Pbx CS 239 lk 29 3^ 316 16.5 These data indicate that pbx is located between Y-, and PI in chrom. 6. G. A. Lebedeff 3* I have just returned from Canal Point, Florida, where two weeks were spent in the examination of corn sporocyte material. A brief statement about the winter planting of corn in Florida, ar- ranged for and supervised by Dr. Jenkins, may be of some general interest. It was an unusually warm winter down there. Corn planted at Canal Point from October 25 to 2S began shedding pollen in late December and Mr. Garrison had finished making most of the crosses in this material by January 20, some 2 or 3 weeks ahead of last year. A later planting on November 2k was beginning to reach the sporocyte stage January 10, and an abundant supply of sporocyte material equal in quality to that obtained during the summer here at Ithaca was 176 a v a i l a b l e during the following two weeks. Tassels were beginning to show in this planting on January 25. The location at Canal Point is well-protected from frosts, the soil is well-adapted to corn, and corn smut which often does so much damage, especially to plants from which sporocyte samples are taken, seoms to be entirely absent from that region. Birds, the ear worm, sugar cane borer, and other pests caused considerable damage this year, but i t looked to me as i f i t should be possible to get at least a reasonably good winter crop down there most every year. A stunted condition possibly due to a length of day effect was noted in some lines, but other lines looked about as good down there as they do at home here in the north. H-. Studies on induced polyploidy and other genetic effects in- duced by heat treatments were continued during the past year. My stocks of tetraploid corn looked much better last year than ever before in spite of the generally unfavorable weather conditions; good vigor, and a very sturdy growth habit characterized a number of lines which were also highly f e r t i l e and in other respects looked very promising. Tetraploidy was induced in both the Durango and Florida types of annual teosinte. These experimentally induced tetraploids were entirely annual with no trace of the perennial habit which characterizes the tetraploid Euchlaena perennis from Mexico. One octoploid was also obtained and i t wasn’ t perennial either, but was dwarfed and s ter i le like the corn octoploids. 5 . Chemical analyses of the carotinoid content of tetraploid corn are under way in cooperation with Professor D» B. Hand, a bio- chemist, with a growing interest in the chemical basis of heredity, preliminary results indicate that the meal from the tetraploid yel- lows has appreciably more of the active provitamin A carotinoids, cryptoxanthin and beta carotin, than the comparable diploid yellows. The diploid yellows d i f fe r widely in the amount of carotinoids pres- ent in the meal, and from some unon-yellows" yellow pigment has been extracted. With what we now know about the genetics of yellow en- dosperm from Perry and Sprague’ s recent paper and from the earlier work, and with the method which Professor Hand has perfected for separating chemically the various yellow pigments in corn meal, i t should be possible to find out something about the chemistry of gene action. 6 . Some progress was made last summer in the improvement of my multiple tester stocks with markers in each of the ten linkage groups. Stocks similar to those tested last year with one 01 more genes added are available for distribution in limited amounts. L. F. Randolph Connecticut Agricultural Experiment S ta . , New Haven, -Conn. - 1. The character previously l is ted as threaded fth) has been found to be allelomorphic to striate (sr ) . An Fp population segre- gating for f 1 , bmp, and sir gave a recombination per cent of 25 for bmp and sr, 25*5 for sr and tSp. The recombination percentage for sr and f-̂ was 59; or no linkage. This seems puzzling since tBg and bmp are 12$ units apart. However, the population was small consist- ing of but 59 plants. 177 2. Trisomic stocks with chrom., 4- as the extra chrom. are avail- able- 3- Unreported linkage of 02 and raq , and g l x and i j : Genes Phase XY x^_ xY xy Total No. % RB 116 597 55*4 109 1376 225 16°2 Ral o2 Rai CB 127 15 15 112 269 30 11 O p Crl]_ RS 31*43 1595 1*487 64- 629*4 20 O p I j RS *405 169 18*4 30 37 RS 753 353 328°2 V5 13 1*452 20* * These plants were grown in a warm greenhouse and hence the classification for w was d i f f icu l t . A ll questionable plants were c la s s i f ie d as v^. This per cent is probably not re liable . 4-. A three-point test involving o g l ^ , and i j gave the follow- ing counts: F1 genotype 0 1 2 I_j2 Total Op + + Wy 513 115 150 9*4- 123 28 23 1513 + g l i i j 930 265 2X7 51 17-5% 1*4.3 $ 3.4# The recombination percentages of o- and ra^ (repulsion phase), also 0o and gl^ indicate that 02 is to the le f t of yq and within 2 or 3 units of Vq. The percentages between o2 and pj^indicate that o2 is 2 or 3 units to the right of v ̂. Stock of 02 is available. 5 . By wrapping developing ears of the composition of A B pi with different colored cellophane we found that the sun-red color w il l not develop when a l l but( red light is excluded, Science 27, Vol. &4-, No* 21S7, pages 4-S& and 4-£>9» More selective f i l t e r s have been obtained and we w il l try to locate defin ite ly in 1937 the wave lengths of light responsible for the production of the sun-red pigment. W. R. Singleton 6. Paired mosaics (twin spots) have been found to involve C, C~, Pr, P, Wx and some unknown aleurone color modifiers. Wx twin spots are very faint and show only in certain material with light iodine staining. The evidence indicates that some unpaired spots start as paired mosaics but one or the other altered ce l l is non-viable or fails to produce tissue that reaches the surface. Unpaired c mosaic areas are usually larger and more numerous than twin spots involving the same gene in the same seeds. Many of these unpaired spots prob- ably do not start as twin spots. In C Wx heterozygous seeds both genes go together in about 60% of both twin spots and single spots and G alone in about 4-0$>. A shift of Wx without C has not been observed. The dark part of a C Wx twin spot may also show a further change to colorless, normal or 178 still darker ce lls . In some cases these are twin spots within twin s p o t s . Wx may shift with 0 the f i r s t time and not the second, or neither or both times. Obviously these results can not a l l be accounted for by muta- tion, non-disjunction or deletion. Some kind of interchange between homologous or non-homologous chromosomes is indicated. Proof of an exchange between the C and Pr chromosomes is at hand in white and red paired mosaics in heterozygous 0 Pr seeds. Such mosaics are rare. Chromosomal aberration does not seem to be adequate to ac- count for the frequent twin spots in which the two parts are equal in size and outline and crossing-over, between homologous chromosomes as shown by Stern for Drosophila (GENETICS 21:625- 730) seems probable. Proof of somatic crossing-over in plants w i l l have to await fur- ther evidence. It may be found in 2N tissue where dominant linked genes are contributed from each parent. The 3N endosperm mosaics are not satisfactory for this purpose. Translocation stocks having either Su or Pr with C and Wx are desired. Seed w il l be appreciated i f such stocks are available. Aleurone and endosperm mosaics vary in frequency in different families from none in a thousand seeds to thousands of mosaics on a single seed. They are easily seen with a low power binocular micro- scope. A Bausch and Lornb BKT5 microscope with a revolving drum and .7 , 1 and 2x objectives and lCx eyepieces has been found convenient. The light is also important. In addition to the well-known plain cpots and the twin spots that are frequent in some families, large cells, giant cells , depressions and outgrowths are easily seen. The growth changes may accompany color and other known gene changes and clearly result from somatic segregation. Depressions and outgrowths- are sometimes paired, alone or with color changes. Somatic segrega- tion has an important bearing on the cancer problem and any evidence should be put on record. D. F. Jones California Institute of Technology, Pasadena, Ca l i f . - 1. Chromosome I. Striate~Ts r ) seems to be definite ly to the l e f t of P, making the order sr-P-br-bm^. One interchange seems to be about 2 units s t i l l further to the le f t . 2. Chromosome 2. Backcrosses involving Ch and a long inversion in chrom. 2 gave 136 recombinations out of a total of *Ui-7, or a re- combination percentage of 30.4-. 3. Chromosome 3* Three interchanges show close linkage with di . The data are: $ recombination Number of with d1 backcross n - 3d 0 109 T2-3c O.S 602 T3-7b 0 A *162 h . Chromosome *f. Most interchanges show l i t t l e crossing—over with su- .̂ Of those tested the following are furthest away: 179 fo r e c o m b i n a t i o n N u m b e r o f B . C . p l a n t s T l~ 4a 0 w i t h T s r 359 6 b 1 . 5 " 1! 0 3 2 0 T2-4d 0 . 2 » T u 5 0 0 Beyond g ig T?-4b 1 6 . 7 u it 2 1 5 T?-4b 1 5 . 0 " Tip-9b 2 2 . 0 » gn l 3 79 j 5 5 * 5 . C h ro m o s o m e 8 . T $ -10a 2 5 - 0 " T8-10b 4-0.0 " ii-1- D i s t a n c e N u m b e r o f Ms O r d e r f r o m m sg p l a n t s i n B . C . 3 -8 a. T - m s g - j , 7 139 y 8b it° a 33 1 8 2 4-8 M 3 4 l i 4 5-8 ( u n c e r t a i n ) 0 .4 276 6-8 T - m S g - O i 5 1 1 5 g-9b H0 M 27 95 g - iO c tl 27 71 (Distance between msg and about 10 units in a l l these ' tests ;--------data varies from 8.1 to 10.9)* E. 0. Anderson Iowa State College, Ames, I owa - 1. Chromosome 1. Genes Phase _XY_ .XX. xY XY_ .Total No. djc Tŝ Gs1 CB 12s 37 46 113 324 83 25.6 2. Chromosome 10. Og R RB 55 193 17s 62 488 117 24.0 F't genotype 0 1 2 1,2 Total 0g_+ + 2*6 225 3 1 3 3 21 34 2 6 618 + l i gx 491 64 8 10. % g . % l . % Og + r 6g 77 17 25 10 21 5 7 230 + ex + 145 42 31 12 18 • 13.5# 5 .2$ 3- Chromosome 4. Order of three linked genes is established by Fp data of small magnitude as; la-sup-w]|. E. W. Lindstrom 4. Further studies with plants hyperploid for the short arm of chrorn. 5 show that secondary trisornes, involving the fragment chrom., 180 ?re found in the progeny of hyperploid individuals, The breeding behavior of the fragment of hyperploid plants is as f ollows: Fragment plant Fragment plant TffQft-gLf of f s Pr ing in # as female____ as male 9^-9fo 2U + fragment 0.61a Secondary t r i somes 0 .5*0 The above data show that the fragment chrom. is readily trans- miss able through the female side but only rarely do male gametophytss hyperploid for the fragment ohrom. function. The frequency of sec- ondaries, however, through the male side is as great, at least, as through the female side. Pollen from secondary trisomes gave only disomic offspring in the limited backcross tests made which indicates that pollen hyperplid for the "secondary’1 chrom. can not successfully compete with haploid grains. Among the questions to be answered are (l) How do the secondaries arise and (2) Ho?; do those male garneto- phytes from fragment plants which bring in the "secondary” chrom. manage to successfully compete with haploid pollen when pollen hyper- pj.oid for the fragment chrom. is rarely successful. 5. Hayes recently reported a new virescent linked with jq and therefore belonging in chrom. 8 . This virescent was designated V£q. Trisomic tests showed that vqg was in chrom. 8. Grosses made be- tween Vqg and v show them to be a l le l ic . 6. v ̂ is linked with an endosperm color gene with k-J$ recom- bination as shown by the following data: _XY Xy xY xy Total ^ recomb. 816 2^1 226 108 1391 kj Tests are in progress to see whether Vq^ is in chrom. 2 or 6. 7. A new viable pale green is in chrom. 9 on the basis of t r i - somic tests. 8. F ̂ linkage data places ws ̂ ten units to the le f t of lgq . The locus of l g q has been shown by FlcClintock to be near the end of the short arm of chrom. 2, so ws-z must occupy a nearly terminal position in this arm. 9. A second occurrence of a chrom. fragment consisting of the short arm of chrom. 5 was found among the progeny of a disomic plant. This fragment is apparently identical with the one mentioned in"item k. 10. A new annual form of teosinte, resembling the Durango variety, was crossed by sh-wx maize. Five Fq plants had approxi- mately normal amounts of crossing-over in the sh-wx region while one Fq plant showed no recombinations in this interval. The Fq ears had $—10 rows of seeds as contrasted with the usual Crowed ears found for Fq hybrids of the other annual forms of Euchlaena. No segrega- tion into types occurred when selfed and sibbed seed of the pure Euchlaena was grown. No admixture with maize was evident as the tassels had no main spikelet. 181 g, 11. Small pollen (sp2) and lg are probably between _g1 and l i with the order li~sp2- lg -g1-R. Plants trisomic for chrorn 10. and having the constitution Spp Sp2 sp2 had about 20$ small pollen (sp2) and about £0$ normal pollen. This'indicates that n+1 pollen of Sp2 sp0 constitution is of normal size and that sp2 is recessive to Spn ir/’such garnetophytes. 12. More data have been obtained on the dosage relation of Dt and a-j_. Three levels of dosage for ai show a linear effect while increasing the dosage of the Dt gene, as shown by three dosage levels re su lts in a non-linear e ffect. The genes Dt and a-, interact to pro- duce the dotted aleurone character. 1 Linkage data for chrorn. 2. Jgenes Phase _XY xY xy Total $ recomb Lei Ws3 RS 480 252 253 3 10 Crip WS 4 RS 231 100 85 9 445 32 Lgi AI RS 361 161 183 0 705 0 Glp Al RS 128 66 50 2 246 19 l4. Linkage data for chrorn. 10. R Lg *CS 1368 179 702 57^ 2824 12> * + Spo + CB 529 130 39 824 1524 ei + 11 is + 1$ + CB 657 33 48 314 341 1393 + l i * (could not classify for sp2 because of drouth and heat damage). Previous data have shown about 3$ recombination for sp2 and lg, and sp2 i ° be fa ir ly close to g-j_. These facts together with the above data indicate the order is l i - sp 2~lg-g^. M. M. Rhoades 13* Linkage data for chrorn. 10. genotype 0 1 2 1,2 Total RP + r 179 161 109 l l4 31 30 16 13 653 + gx + 340 223 61 29 34.2$ * 9.3 $ 4 . 4 order is Rp-g Rp_ + + 223 , 90 40 13 36* + l i gi 24. % 10.9$ 3.6$ order is Rp-1: * (seedlings inoculated in f la ts and only resistant individuals transplanted to f ie ld , to prevent spreading the rust to other cul- tures ) . - - - es- Lk&s® _JCY Xy xY xy Total *$> recomb. Hp d7 r s 409 127 133 4-1 710 50 182 1—1 Singleton reported 35$ recombination between Dy-Ĝ and 27$ between p -r . This suggests the order is G- -̂R-Dy, but might be different. However, i f Dy fa l ls to the l e f t of R i t should show fa i r ly strong linkage with Rp, but i t does not. Therefore the order in chrom. 10 is: Rp l i gi R d7 0 20 01! V. H. Rhoades 16. The following data were obtained from three-point tests involving gly , i j , and bdy: Fi genotype 0 1 2 1,2 Total + + bd 344 271 37 26 255 19s IS IS 1167 eh + 6x5 63 453 5 H 38.84 3 -lfc 1/. Data were obtained on a dominant or part ia l ly dominant char- acter which we have been calling knotted leaf and designating by the symbol Kn kn. A fu l l description has not been published. Superfi- cial observations indicate a more rapid growth of the vascular tissue, resulting in a kinking or knotting of the veins. Plants known to be heterozygous for this character usually make normal growth with only an occasional knot on the leaf blade and a slight knotting of the leaf sheath. Other plants proven to be homozygous were so badly knotted that the tassels could not make their appearance without assistance. Backcross data were obtained in 1933 on 531 plants and in 1936 on 252 plants involving the genes f , tsg, and Kn. The combined data for the two years are as follows: F-j genotype 0 1 2 1,2 Total + + Kn 171 125 101 161 94 31 29 71 tS2 f l + 296 262 7S3 125 100 33-5$ 16.0$ 12. H A marked deficiency of plants in 1933 made interpretation of the data doubtful. The results in 1936, however, were very similar to those in 1933, Backcross stocks involving the genes for br, f 1? bm2, and Kn were obtained this year for classification in 1937. A. A# Bryan University of Missour i , Columbia, Missouri - !• Gig and g i g have become mixed some time in the past and the stocks of gig which have been distributed are g ig . An ultra-vio let induced glossy is tentatively assigned the symbol g i g . 183 The linkage relations of g ig are l is ted below: Genes Phas e _XY xY xy Total recomb. Qt Orl A RS 339 175 77 1 592 10.0 pr Crl6 RS 305 169 16k C 63g S.5 ( i f 1 xy) Vp2 ^6 RS ikB 74- 93 1 316 10.5 2. 01]_q (not the one reported by Emerson) is in the 9th linkage group. A small F̂ repulsion gave no double recessives with wx. 3 . Intercrosses were made between 16> newly-acquired glossies and glossies 1-10 inclusive. Due to the unfavorable season, seed was not obtained from many of the crosses. However, crosses were com- plete enough to suggest that this group included some new glossies. 4-. Intercrosses have been made between Had.jinov’ s and the writer ’ s glossies. The following identities have been established: h g ij = sii).; h g i 10 = s i y , H £15 = a lio ; H file = file (see News Letter of March g 193'=’ , page 3) • His stock designated Gig g ig did not segregate and his stock g in has been le tha l under conditions at Columbia. 5 . Seed has been sent of a new dominant character tentatively designated ’’vestig ia l glume” with symbol Yg. In the presence of the dominant a l le le Vg there is almost complete suppression of glumes in both the staminate and p is t i l la te inflorescence. G. F. Sprague 6. The following l i s t of mutants is submitted as a sample of the types of mutant observed following treatment of pollen with ultra-violet radiation. The l i s t includes the seed and seedling character mutations observed in experiments recently reported (Proc. Nat. Acad. Sci. 22:572-57&) in which unfiltered radiation from a commercial quartz mercury vapor arc was used. Similar mutants have been observed in later experiments. Many of the mutants l is ted are of l i t t l e value for general genetic purposes, because of lethality or low v iab il ity ,^or in a few cases, because of overlapping the normal type. In (2), (15 ), and (33) the parent Fn plant had defective pollen, but the mutant ap- peared to be unrelated to the factor causing the pollen defect. In all other cases the parent Fj plant had normal pollen so far as could be determined by pollen examination. I t is possible that pong the mutant seed characters reported there may be included instances of small seed due to heterozygous deficiencies not mani- fested by defective pollen development/ Tests against this possi- b il ity have not yet been completed. Description Mutant (seedling character) Notes a ) red leaf dark to faint red colora- not distinct on ma- tion in seedling leaves ture plants virescent some seedlings virescent possibly two separate yellow-green-a yellow green, others near mutants; may be asso- white ciated with small seed 184 /■z'j glossy-a glossy seedling with possi- occurred with a small bly some normal overlap seed, unlinked ( 1+ ) yellow green-a clear yellow green, later develops necrotic areas and dies (p;) virescent nearly pure yellow at probably a usable yellow green-b emergence; turns green mutant (6) rolled early seedling leaves many die but a few tightly ro lled and survive to produce adherent normal mature plants (7) dwarf dwarf seedling and plant not induced; possibly a recurrence of dwarf 3; closely linked with wx (3) corrugated leaves narrow with well occurred with aleurone marked corrugation spot; original materi- al showed complete association with aleu- rone spot (9) virescent nearly pure yellow on emer- probably a usable yellow green-c gence, gradually turns a mutant greenish yello?/ (10) speckled seedling leaves prominently speckled and semi-dwarf (11) yellow seedlings distinct yellow may be viable green-b green; do not green up in seedling stage (12) glossy-b clear glossy indication of linkage with pr; tentatively designated as gig (13) virescent seedlings appear luteus lethal yellow with slight greening (1*1) yellov/ segregates for yellow green occurred with a germ- green-c and white seedlings less, unlinked (15) white tip seedling leaves have a dis- occurred with an un- tinct white tip; present associated pollen also on some ma.ture plants segregation 185 (16) germless-a (17) small-a l/S-l/k normal size deficiency of small seeds (1$) small-b 1/10-3A normal size; very occurred with a vires- irregular shape cent yellow green, unlinked (19) aborted very small and poorly a l l aborted seeds are developed germless, but some normal size germless seeds present (20) small-c clear separation, approxi- many small seeds are mately 25^ recessive type germless (21) small~d seeds normal in height and occurred with a glossy width, reduced in thickness seedling, unlinked (22) miniature-a seeds reduced in size and characteristically scarred (23) miniature-b variable in size with prob- able normal overlap (21!) miniature-c seed size reduced but with occurred in check, probable normal overlap not induced (25) aleurone spot aleurone layer absent in occurred with seedling scattered areas over the character corrugated seed (26) small-e seeds normal width and l/H- only slight deficiency ~3/^ normal height and of small thickness (27) germless-b seeds normal in size marked deficiency of germless seeds (28) miniature-d seeds about 1/2 normal a l l miniature seeds size, some normal overlap are germless (29) small-f seed reduced in size small seeds are germ- less (30) gnarled seeds small and variously mis-shapen (31) shriveled seeds poorly developed and shriveled are also shriveled germless 186 (32) rrdniature-e seeds l/2~3/ ̂ normal size small seeds not germ- apparent ly clear separation less (33) miniature-f seeds reduced in size not germless (3I ) gerrnless~b seeds nearly normal size (35) scar scarred seeds range from I /8 to normal size (36) miniature-g seeds 1/&-1/2 normal thick- ness and 3/4 height and width (37) germless-c many seed also scar occurred with vires- cent yellow and white seedlings, unlinked Further information regarding these mutants w il l be included in a research bulletin of the Missouri Agricultural Experiment Station. C. F. Sprague and L. J. Stadler. Agricultural _Experirnent Station, College Station, Texas - 1. Several years ago we reported a new type of sugary, "amyla- ceous sugary," the inheritance of which depends upon two factors, one of which, su—am, is allelomorphic to su^, the other du being located in chromosome 10. The genotype suj- su?-- Du Du is indistinguishable from pure starchy, while the genotype sujp suy- du du is a good sugary though not as wrinkled and translucent as ordinary sugary. Since the presence of the du gene in homozygous condition can con- vert suip suip from starchy to sugary, i t occurred to us that this same gene might have a similar effect on ordinary sugary, sû SU]_, converting i t to a "super sugary." Chemical analyses of ordinary sugary, sû su-, Du Du and "super sugary," sû sû du du, have been made which confirm this assumption. The former has ^8.7 per cent total sugars, the latter 62.6 per cent. Several commercial sweet corn varieties are now being converted to "super sugary" by intro- ducing the du gene through repeated backcrossing to determine whether this gene w il l have any value in practical sweet corn breeding. 2. In a stock derived from a cross of Tripsacurn and Zea, com- prising 20 Zea and 1 Tripsacurn chromosomes, the extra Tripsacurn chromosome carries the allelomorph of the sugary gene. This chromo- some shows regular, though not complete pairing with the f i r s t chrom- osome of Zea and not with fourth on which the sugary^ gene is located in Zea. 3. Tripsacurn is apparently homozygous for the A factor. Its composition with regard to the C, R, and Pr factors is being deter- mined. 187 4-. Corn seedlings l e f t in refrigerator for brief periods showed frequent islands of tetraploid tissue in root tips. Treatment of ears with dry ice soon after pollination has not produced any tetra- ploid plants. 5 . A new gene for premature germination, or vivipary, is linked with sup. A new gene which causes a peculiar mottling of the endos- perm appears to be a usable endosperm character. Linkage tests are being made. 6. Observations for several years have indicated that 3 factor causes plants to bloom earlier. Extensive data this season on date of anthesis in B and b plants from same segregating progenies show no significant difference. 7 . A study has been in progress for several years to determine whether the marked differences between Suchlaena and Zea are genic and whether the genes which differentiate the two genera can be lo- cated on definite chromosomes. Four chromosomes have been studied, using marker genes from corn, and i t has been found that the V-Pl genes are de f in ite ly linked with genes for number of tassel branches 3-lgp genes are linked with genes for height of stalk, number of t i l lers , number of leaves, number of ears, and number of tassel branches. Waxy gene is linked with genes for number of t i l l e r s , number of leaves, and number of ovules per ea.r. supTu genes are linked with genes for height of stalk, number of leaves, number of ears, number of tassel branches, length of es.r, number of rows of ovules and number of ovules. So far as the results go they indicate that the genes which differentiate Zea and Euchlaena are scattered at random over a ll the chromosomes. P. C. Mangelsdorf and R. G. Reeves Univers i t y o f _Wisconsin, Uadison, Wisconsin - 1. Linkage data on Chrom. J: Genes Phase XY Xy xY M. Total re comb g2~d1 RS Ski 85 13 4-23 38 Rg-Ra2 CB 61 I t 4-1 77 197 30 Severe drought injury made accurate classification of cr and im- possible. The g2-dp results, however, indicate that go may be in chrom. 3 » Genes % recombination A - Lg2 39 ' ap__ lg£ + (X) A - Ra2 4-5 + + ra2 Lg2-Ra2 5^ The data of these two tables (together with earlier findings) indicate that the ra2 locus is in the neighborhood of dp, probably between dp and cr. R. A. Brink 188 University of West Virginia, Morgantown, W, Va. - "-----1 . Linkage data on Chromosome 2: Genes Phase XY XI xY re comb. Alr-B CB 30 15 15 u RB 50 127 n s 57 2. Linkage test with sup: F-j genotype 0 1 2 1,2 Total + pi + 189 163 64- 52 11 22 k 2 507 yx + su2 352 116 3 3 . 6 2 2 . s .% 1.2 # (separation of Yp-y^ poor, especiall}^ in sû class) C. R. Burnham Bureau of Plant Industry, Washington, D.C. - 1. Recent morphological studies of the chromosomes of strains of Indian corn and of teosintes from the experiment station at Chapingo near Mexico City have shown several strains in which chromosome 10 is abnormal. This chromosome has a piece attached to the end of the long arm about the length of its short arm. This piece is much knobbed and at present nothing definite can be said concerning its origin. A small quantity of both corn and teosinte seed carrying this abnormality are available for distribution. A. E. Longley 2. In connection with making the corrections in the linkage summary pointed out on page 3 of the March 4 Maize Genetics Letter, I note on page 3̂ that wq is l is ted as reported by Bernerec 1923B. I assume that this should be changed to Lindstrom as on page 25. F. D. Richey 1I ‘ Col l ective Publication of Linkages Some of the linkage data presented in this News Letter would seem suitable material for a general linkage paper to be published, (see News Letters of March 6 and November 30, 1935 > and March ty-, 1936). I f the authors of these data w il l signify their desire to have it published as presented in this News Letter or w il l rewrite i t in the form they prefer, we w il l attempt to make arrangements for hav- ing i t published this summer. I f others of you with similar data will send i t to the Co-op. not later than April 10, we shall be glad to include i t in this publication. In the News Letter of March 4, 1935, Dr. Emerson gave some very t good suggestions regarding the manner of arranging the linkage data: "Manuscripts should be typed and ready for publication without change. When new genes are involved, a short, concise description of the characters differentiated by them might well be included. 189 Well-known genes should not require such treatment. Tables should be presented in summary form. Different cultures involving the same kind of data should not be l is ted separately unless that is essential in order to demonstrate significant differences between them. Of course F2 an<̂ beickcross data for coupling and repulsion must be entered separately in the tables. A single frequency distribution rilay often be displayed in the text to better advantage than in a table. Tables of data should be accompanied by such discussion only as is essential to make clear any points not obvious from an examin- ation of the tabular data themselves, or as is necessary to indicate the relation of the unreported observations to other linkage tests, etc. The tabular arrangement and headings used in the Linkage Sum- mary are convenient and I, naturally, think them good. No limit can be set now to the length of the individual contributions, but, unless a very considerable amount of data are presented, individual papers might well be kept to not over one or two pages of printed matter, and i t is my hope that some may be not more than half that long". I I I . Seed Stocks JGrowrr, 1936 Inbred strains. Selfed or sibbed ears of a l l the inbred strains in disease resistance test. suq glj$ Yq lâ lpa. (a l l e l to lap) r Prq mr (mottled aleurone-Horovitz) may seg. gq Homo. A-j C R btq bv prq Homo. Aq C R a? b t q bv prq seg. v2 Homo. A-j C R A2 btq bv pr^ Inbred line of supergold pop corn (Jenkins) seg. cultures of y^ y^ It It x Yg i t i t y;+ y ̂ I t I t ax c r prx i Trisomics 3> and 6 Sweet Britt le (L n• \S • Raymond) seg. cultures of l g q gs2 b X I g l gs2 b v^ it tt it yt X aq na ts 1 it it â Dt x al lg 2 B PI 1 m it a2 X V p prl bniq A 0 R it tt it R g i nil X zb^ 190 aUj au2 sh da aup aup sh a-j_ na ts^ Dt glp wx TP gj-l ral v5i/' al ^ 2 Dt ar wx gp ^1® D1 hf bm̂ Kn gi gi5 vx (Wiggans) f r l f r 2 g i i iJ ^ p tsp br fp bm̂ yg2 lgl g l2 b vlp l g l g l 2 3 VJ, A1P1 sm seg b i l msg X jp Msg/msg gU x yg2 c sh wx r l zb5 No germination: <17 gx X gig A-jC r sh wx yp prp Su/sup x dx SUp Yip Yip i t i t Too JL ate: y&3 seg. l g ^ ms vai a f3lpa (= a r is t i fo l ia ) g l33a (= g l2> sn (= siamensis) gl^P, (amargo corn) 10 pkges. of seed from Australia (Note: this seed from Australia is of various inbred strains, devel- oped at Queensland Agricultural High School and College, which show seedling characters such as f ine-stripe and virescent. These char- acters ought to be studied in a region with a longer growing season than at Ithaca. A small amount of this seed is available for d istr i bution.) 191 lg. IV. Seed Stocks Received for Pro pap; at ion in 1937 1. A. A. Bryan, Arnes, Iowa:- br bm2 kn x + +__+__ Kn br fp bm2 + +__ bd x glp i j bd g l l ' i j + 2. R. A. Brink, Madison, Wisconsin:- Ap lg2 x Ap lg 2 ts^ d1 al ^2 ra2 ax lgg di x Ap lg2 dp tS[|_ }. G. F. Sprague, Columbia, Missouri:- b gfg Ig i Vg x vg vg 1, J. Shafer, Pasadena, California:- (inbred x sb)# (sb x A b pi Ypy[_ su2)# yl su2 5. A. E. Longley, Washington, D.C.:- Indian maize carrying an extra piece attached to chrom. 10. Teosinte (Tecubaya) carrying an abnormality similar to that found in the Indian maize stock. 6. J. H. Kempton, Washington, D.C.:- Teosinte from Mexico- Novocayan, from the hacienda of that name near Durango City (from the same place as the original Durango seed). Nobogame, from the town of that name in Southwestern Chihuahua. Represents the farthest north for teosinte. Trampas, from near northern border of Durango. 7. G. A. Lebedeff, Ithaca, New York;- pbx wx yp PI sm x pbx 8 . S. Horowitz, Buenos Aires, Argentina:- a (dominant japonica) x ApC R sh wx B pi 9. R. G. Wiggans, Ithaca, N. Y . :- Chlorophyll types - Yellowish green seedlings Dark green Rather light green Medium to light green Good foliage, leaves broad, excellent in general appearance Yellow stripe 192 in R. A. Emerson, Ithaca, N. Y. + g n + (x) SUi + 02 + Tss sup (x) wl + + + SUi e i 3 (x) wl + + + Tem. sui (x) la + SU-ĵ 11, C. A. Krug, Sao Paulo, Brazil Variety Numbers Characterist i c s Ratios Amarello 41B-1B segregating mealy endosperm (3 : l ) I! 47-1 "brown pericarp" bp ? (3 : l ) ? It 03-1-4 seg. dwarf plants (3 : l ) Crystal 96— 4—1 seg. tassel seed (3 : 1)? it 97- 1 "ragged" Rg ? 3 : 11 111- 2-3 "oily spots" (blotched lea f)? it 119-6 branched ear (homozygous) Amarello 12 9 -1-1 striped leaves 3 : 1 Crystal 134-2-1 semi-dwarfs 1 137-1-3 seg. zebra seedling leaves 3 : 1 Amarello 146-1 semi-dwarfs (homozygous) 1 14-9-2 "rolled leaves" ro ? Crystal 150- 1- l a seg. defective endosperm 1 3 : 1156 "rolled leaves" ro? (homo.) Negro 164-2-1 colored pericarp and aleurone Morango 109 A variegated pericarp Amparo 242 seg. defective andos. sh ? 3 : 1 Crystal 256 brevets in the tassel Amarello 254-1 male s te r i l i t y 3 : l tt 266-1 zebra-striped leaves (homo.) Hickory King (?) 267 defective cob Rwp, Rw? (?) Crystal 200-1 "crinkly" cr ? (homo.) V. List of C-enes Not ir. Co-op The genes that have been reported and are not in the Cooperative Collection are l isted below. I f you have any of these genes in your seed stocks, w i l l you kindly send us a few seeds so that we may get a stock for the Co-op? Your cooperation w il l be greatly appreciated by a ll who are interested in having available in a central repository a complete set of maize genetic seed stocks. a3 e h o gm0 adp m 2 gn>3 gmij. an 2 Hs d 15 193 le Ip me bn£ Md me mg btj mi na2 °3 cb Og oy Pb2 C Tp pbj pcl~^ pg3~io pm h Pil p i2 d6 Pr2 ps Pu1 Da p ^ 2 raP rel_H dePi ro HP rt de^ sl~5 sa0c sc1 sf del - l 6 S°2 s0l dl so2 su-̂ sy dm th twi-3 vio du va2 VH> 13,15,16,19 vax f 2 VP3 wl4-10 wa f 3 wŝ xnl , 2 Y2 fs yd yf ygi,3 go Yp ya2 Z '°1_lL gel~ l5 z^ l ,2 VI. Test 8 of Inbred Strains for Disease Resistance Last spring seed of f ive inbreds furnished by Wiggans, one by Hayes, one by Kvakan, three by Bryan, and f ive by Singleton were sent to eight cooperators in various parts of the United States. The severe drouth and heat in some areas made possible a good com- parison of the inbred lines in regard to resistance to f ir ing . The following tables and supplementary notes on the inbreds were received by the Co-op.: 194 1OJ ,—o1 Ar 1 ington Experiment Fpj:m, Rosslyn, Virginia - Total No. No. Date No . Erect Smutted Line Silked Plants Plants Plants Remarks Co 206 7/30 27 3 0 Very l i t t l e pollen Co 20S 7/26 34 13 0 Good line Co 210 7/30 36 1 2 Co 211 7/26 33 21 0 Pollen 5 or 6 days later than silks Co 214 7/26 29 1? 0 S2S3 7/30 14 12 0 I 234- g/10 29 17 0 Dr 2{6 A 8/10 30 9 0 ID ^56 A2 g/2 23 22 1 Very good line Kvakan 6991 7/30 9 2 0 Light green & spotted No good here Singleton C2 25 0 Too early. Entirely it C6 36 2 unsuited to tt C13 39 2 Arlington f! C85 33 0 conditionsIt C78 34 1 M. T. Jenkins AmeSj_Iowa - The season in Iowa was so unfavorable that observations must not be taken too seriously. Early lines were more affected by these conditions than the later lines. No attempt was made to hand- pollinate any ears. Under open-pollination the set of seed was fa ir on some lines and poor on others. The season was good for testing smut resistance, the smut infec- tion being about as heavy as in 1935- The following notes were made on the inbred lines: C 206: Free from smut; no f ir ing of leaves, tassels good, ear shoots good but poorly f i l l e d ; roots weak; plants about 5 * high; ears about 1-|- to 2 ’ high; not very promising. C 208: Smutted ears on about 30$ of the plants; tassels good; one or two top leaves fired; plants erect; ear shoots good but not very well f i l l e d ; tendency toward 2-eared condition and some multiple earing; rather promising stock except for the smutting of the ears. C 210: One smutted plant in a total of J6 ; roots weak, badly lodged; not at a l l promising. C 211: No smutted plants; extremely early, very short plants; pro- duced considerable seed; a useful stock. C 211i: No smut; roots very weak; unproductive; not promising. S 283: No smut; early; lodging-resistant, at least until late in the season when a tendency toward stalk-breaking became apparent; produced a fa ir amount of seed for the season; probably a useful line. Kvakan 6991J About one-third of the plants had bud smut; stalks weak, broke badly; not promising. I 23'i: Rather late compared to others in this group but also re l- atively good; only two smutted plants in a total of 33 (bud smut); good set of seed; promising but possibly rather late for general use. 195 Dr 276k: Two suckers with ear smut and one plant with stalk smut just below the ear; short, thick, w e l l - f i l l e d ears; very weak roots; not especially promising. WD 4-56A2: Four plants with small bud smut galls near the base of the plant; no lodging; ears fa ir ly w e l l - f i l l ed with seed of excellent quality; poor pollen producer; re lat ive ly late; an excellent line for Iowa conditions but probably too late for general use. Sweet Corn Lines: All of these lines were so extremely early and made such poor growth under the prevailing conditions that fa ir judgment can hardly be passed upon them. They were nearly or quite smut-free. Numbers C6, C13> C7&, and C&5 had a fa ir set of seed. They are not promising for our conditions. A. A. Bryan Columbia^ Missouri - L in e F i r i n g No t e s Co 21 -̂ yellow green in color; no ear shoots S 233 tassels were blasted on 7/6; f i r s t silk appeared 7/9 Co 206 wilted badly followed by f ir ing and tassel blasting; tassels blasted 7/15 Co 203 l i t t l e f i r ing but tassels blasted 7/15 Co 210 l i t t l e f ir ing but tassels blasted 7/l§ Co 211 upper leaves fired; tassels blasted 7/9 Kvakan 6991 very slender stalk; yellow green color; tassels blasted 7/9; f i r s t silks 7/H Dr 276 A lower leaves f ired 7/17; pollen shed 7/17 WD ^56 2A silked 7/13; a l l tassels blasted by 7/17 Bryan 23^ upper leaves f ired 7/15; f i r s t silks 7/20 No rust, bacterial blight or smut was noticed in these cultures, None of the strains produced ears. G. F. Sprague 196 Durham2.JOrth Carolina - Approximate order of Number of diseased Miscellaneous adaptability^ observed Maturity observations Group I (good) Smut Rust l,*Dr 276-A 0 0 late general appearance sturdy 2.*C0 200 0 13 ( 50$) med. Rust injury negligible 3_«s 2S3 0 0 med. 4, * WD "̂5 —̂ A2 0 0 med. two plants runty Group 2 ( fa i r ) 5. Co 210 0 0 med. seg. small plants 6. Kvakan 6991 0 0 med. 7. 1 234 1(5$) 0 late g.*C 72 1(3$) 0 med. Group 3 (poor) (not in order) c 05 1(5$) 0 med.-late Two "Fp hybrids'1 ruled out. #Co 211 0 0 med. General appearance satisfactory Co 214- 0 0 med. Very few seeds on open—pol. ears Co 206 0 0 med. Not much pollen; prob- ably protandrous c 13 0 0 early C 2 0 0 med. C 6 0 0 med.-early * eight to 20 h ana-pollinations in each of these inbreds. # a l l pollination failures were of same date. This inbred may deserve better rating. Conditions prevailing here last summer were in general too favorable to afford a rigorous test. The weather was consistently hot but rainfall was adeouate (for late plantings which included these in- breds). No f ir ing , no lodging, and no bacterial blight was observed. The infrecuency of smut and rust infection in the inbred lines may not mean much, since my cultures generally suffered l i t t l e from smut and rust. T had occasion to use some of these inbreds in crosses and also made a lew se l f and sib pollinations in eacn line. The rating as to adaptability is based largely on the results of these pollinations. The proportion of successful pollinations and the yield of grain resulting provided a basis for rating. H. S. Perry 197 198 Burnham CO CO o o c o CO O CO CO M S3 w P H- H- P H- 0 0 0 3 0 0 B = O O 3 * * H> * ON' OI -^J r o I 1 T f ? ? - 0 9 VO I—1 i—1 I—* HVJ c > j i—1 0 9 o no *~3 P J > < k J k S r S k * S r S r S CD CO CD ro H h - ya 8 3 0 0 O H- v j i v j i c n - k 4 ^ ONVTI 4=" ONVTI V k - P O n C+ V J l V J l yj aq O V k V J l o - P " O 0 oa oa o n - f ^ - p v j i v n o v k r o o 0 V o P CO c + p CO i—• H* P c + ! o ' P — o r o •n j h r o v o 0 0 S P o v n o v j i o o o o o o o o r o o o - p P | c+ H 0 P O P > 5 i H p O 7-1 c+ H* H V k P* H P H o P o v j i o o v j i o o o o o v i o v o o o r o 74 P p 0 74 0 P O' P H* 0 H < < P> H C ro Hj H o q i h Hj oq »c ( f t v v ro p • • p o p O I p p O O O O O c + H> p =<; H* H- H- o H* o 1 H* H* O O O O O 0 ro c f 4 P 1 H H p , 4 p , 4 H p c q p cq cq p P H c*f H* + o o o I H* 0 O o o o P P P yq c + p 0 p p r o • cq p Cq 0 o ' O p p * d 0 0 0 0 0 p 0 P H P P H P o o P O O CQ - s v r r c+ ~ ~ o V. o o O H O O H O S i V / J O O O O 3 v> • H P c + - v o VJl 0 0 09 r o - ^ i p • • O n * O 4=* o p • - N l - s l O J • r r h CO Vk v o Vk H 3 • • no P H c + l J l - PVH H - PVJI VJI VJl H H H H H H H M M V I • H - o H o no r o 09 H v n h v o v j j v j n I v o v j i v o p o V J l O n P • C+- o v o O n m P < r o ro yd * <; r o h 0 c + ct* p o ' p p o o « J M - F=* P 4 o a O n P M o O n o n 3 • f =* 3 0 0 0 > > O O n 3 no O V O P V O M o o t o 3 P 03. o a c + o o a 3 o a p o a o a 03. —o - o w c f M 0 M M M M O t o r o M J H * 3 O x ! 4 0 * P c + < ! 2 M CL> ) 1 CD 4 4 ) ) CO CD CO O c + Oq I o o p M M M < H M M M M M M M ' on' oJ o O - V ON V O o - v v o o a s p c + CO O O O t ! o o O CO O O j c+ CO o o o o o o o o o 0 Q M P o M M M r o m r o 4 o V n I V O V V - J=" oa - r - V M O o a co p . P M M P3 M C\M v j i I £ r o o O V I O r o M TO • P " O O C + 0 p U 1 p H - 3 I I M M M M M M _ M SJ 3 M M r o O n J p r o m - P 0 o o ? f no r o 1 o 1 c + I l n o M M M M M M O 4 C?N O N o a O N O N 3 4 H* 4 0 0 0 H* H* Cq od 0 <4 P 4 4) 4s m "d *d H- M o 4 M P M* 3 O 4 4 0 o 3 4 O 0 P P M • 4 M H* 0 o 4 o O M* 4 4 4 Moq o o 0 4 . 4 M 0 4 o 3 0 M 4 0 4 0 * < CD p 4 M H- 0 MC3 4 P O oq M MOq 0 3 0 4 *• O P 3 4) P 4) p Sa P oq P c + H- 4 6 0 H- H- 0 4 4 m 0 4 o P o 0 v. 4 *3 M M c + M M 3 M M o CO o 4 O 4 M P M 4 4 4 P M P 0 *■» co-op e r e ^ a b i e ^ t o ^ e t ^ 13!1, ?f 3a ize geneticists found that t h e y ^ leading journal-8 thev^1" ll ?kafG datu published in some of the ides of corn- blning their rclativefy r” u °?nccive? the and lishing collectively T h i t0 one l£,r«er P«Por pub netics -nd r" ~u6gestio n was approved by the Editor of Ge e-^to^olV^ ftiz? Genetics Coop- eration signified’his wilii ngn te oniv°llect the individual papers - for the publication. But te d *n received by the Co-op. Perhaps the r eason terhhte h P"r bGof response from mt'.ize workers has been due t o sonr mi c of the author auch^f^he^a ateri-l^T p®"3lih ° n oml i d e h b ^ indic°t?iete’ bUt rather i ^ e r e I y P s t.ained^in"their 1studie«°!1n'i'V nre\illingnfhrVe °b' to other workers in thi- -i/ te n Ullng to pi!ES on with maize, dome of the spc‘e:‘ up progress lete and should be* publishe d so" thrt°it comp ? a t e e ^ e yo ^ other g lnet^sts.^T i? ; in Co-opriio^eLetter t e ' t h e ^ ^ l f inCiu Previous circular letter- L u n / 0?0 es in nnJ " t f 6f „pi n » c i r r „ 2 l r r; - (j collec- tive publication. " UlG'A ln th 202 ’’The aetails of the method of hen:.;ling the material in the proposed collective public;.-tion of linkage studies in maize will, of course, have to be worked out cooperatively between the publisher and the Maize Genetics Cooperation. During the several years thet this idea of collective publica- tion has been discussed among maize workers, the following plan has been formulate;. Each cooperator who has linkage data which he considers useful and of permanent value to other geneticists, shell write a short paper in the same manner as he would if he were to publish independently. Then each of these papers \ ill be sent to the Secretary of the Maize Genetics Cooperation, who will group then into one larger paper with an introduction, etc., and will serve as author of the collective paper. The- impor- tant point is that each short paper T-ill bo an indi- vidual and separate unit within this larger p:per, with the name and address of the author affixed to it. The Secretary of the Maize Genetics Cooperation shall be responsible for the organizetion and compo- sition of the whole collective paper, but the respec- tive authors of the ’unit papers’ shall be responsible for their data. This means that any citation from the collective publication must include the n me of the maize worker who furnished that particular data.” Dr. Dunn has written: ”...... there is nothing in the policy of GENETICS to interfere with publication of maize linkage data in the form you suggest. Our numbers early in the year arc likely to be the heaviest so May or July pub- lication would fit our schedule best. Submission of the first paper in February would, be most convenient for us.” It is suggested th; t you write your contribution to the News Letter first; then excerpt certain linkage data from it nd write separate prpera(s) to be included in the collective pub- lication. The particul; r data which you select ror public' tion will appear in both the News Letter and the group public; tion. For further inform tion concerning the general form of a. linkage- paper, see the Co-op News Letter of March 4, 1936, p-ge 2; or March 23, 1937, page 15. Sincerely yours, D. G. Langham, •Secretary 203 M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A , N E W Y O R K January 22, 1938 To Maize Geneticists :- A number of maize geneticists have already sent in their items for the annual Co-op News Letter * and many of you probably have your contributions in the mail new. The final date for the receipt of material for this 1938 Letter is January 31st. In the circular letter of November 17, 1937, I dis- cussed the proposed collective publication of linkage data in such detail that the cardinal points were apparently lost in the shuffle. In brief, the plan is that linkage papers, any one of which in itself would not be sufficient for sepa- rate publication, will be sent to the Secretary of the Maize Genetics Cooperation who will group them in much the same manner as in BIOLOGICAL ABSTRACTS and send then to the Editor of GENETICS for publication. Each unit paper must be written as if it were to be published independently. No alterations or additions will be made by the Secretary of the Co-op. In order to be included in this collective publica- tion, your paper must be received by the Co-op not later than March 31, 1938. Sincerely yours, £>. A . D. G. Langham 204 1)o [. / ̂ " M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A . N E W Y O R K March 6, 1936 To Maize Geneticists The material in this letter was obtained from many sources, and has been organized under the following heads: I. General News Items* II. Seed Stocks Grown in 1937- III. Seed Stocks Received For Propagation in 1936• IV, Miscellaneous Co-op Items. V. Gene Index of all the Co-op letters. VI. Chromosome Maps of Maize. A. Regular map: few genes, loci fairly definite. B. Working map: many genes, loci not well established. Most of the information in this letter is given as it was received by the Co-op, but a few changes were made in some of the tables to conform to the accepted system of arrangement. I* General News Items University of Minnesota, St. Paul. Minn. - 1. Zebra seedling, zb) , has been located in chromosome 1 by the following studies. 4 Denes Phase XI xY IX Total Re comb. Zb^ Br RS bb& 14-2 152 12 75^ 31.1 Zbll Fx RS 11-55 135 15s 9 757 28.0 Zb]| Bm^ RS 1+S7 103 li+h 23 757 1+6.0 Zbj| P CS 266 2^ 5 6b 359 6.9 Progeny of 1 ear indicated that the P parent was heterozygous giving the following segregation tt cs 63 30 2 2b 199 6.7 2. A culture of ra^ received from Dr. Brink at Wisconsin proves to be similar to "the one I have studied for many years. There is some variability in type of ear, some cultures showing rudimentary male flowers on the tips of some ears, irregularity of rows on the cob but no division of the cob as in r§i* Other cultures have a divided cob on the tip of the ear but a solid cob at the base, Ra^ can be separated from r§2 in the F2 of a cross. H. K, Hayes 205 3. Virescent seedling. A virescent seedling in Minn. #13 corn was found to be linked with japonica and given the symbol vnj . ghoades (Co-op News Letter, March 23? 1537) has found y-^ and -be allelic after trisomic tests had placed ypg also in chrorno- some 3. Further linkage data of ip ? wsg sind Vf6 are as follows: genes Phase XY M xY M Total rfo Recomb, RB S2 565 h 542 1260 12.1 vi6 71 RS 11+9 154 4- J1 ?16 35^ 661 16.9 CS 4-6*1 39 23 135 661 9.5 Msg Vl6 RS 337 150 171 3 661 13.9 The order of the genes appears to - msg - vl6 • 4. Zebra striped. Eme rson et al list five cases of zebra striping that have been reported. There are two types, one that is expressed in the seedling stage and which may completely dis- appear in partly grown plants. The type reported here was obtain- ed from an inbred line of Del Maiz sweet corn furnished by J. D. Barnard of the Minnesota Valley Canning Compaq'. The season in 1936 was very hot and dry. Germination of sugary seeds was much- lower than normal. Zebra striping could not be classified until late summer when the weather was cooler. Classification was diffi- cult in some cultures. The results given in the summary indicate zb̂ is located in group 4-. Genes Phase XY Xy xY *y Total °jo Re comb. Zb. Tu CS 4-10 6*1 64- 90 62S 23.3 zb6 Ol, RS 326 l4g 135 19 62S 33.9 Tu GI3 RS 3114- 160 147 7 623 20.5 Zb^ Su^ CS 4-227 259 175 361 R022 13.3 The order of the genest appears to be Sup - zfe6 “ Tu - gl H. K. Hayes and M. S. Chang University of Missouri, Columbia, Missouri 1. Of the unknown glossies grown in 1937? tests were completed on one which was found to be different from the other ten and has been assigned the symbol glpp. This was an X-ray induced mutant. One of the ultra-violet induced glossies proved upon test to be gl9. Tests on three others have not been completed. 206 TC CO I-\ In a previous report it was stated that somewhere along the line pi5 and pig had been confused and the present stocks of these are identical. Since the symbol gig has been used in print for the glossy on the 5th chromosome, this designation has been re- tained and a new glossy assigned the symbol gd.5. 2. Glossy 7 has been tested with j^ msg with no indication of linkage: Genes Phase XY Xy xY xy Total Re comb. ffly Jx CS 150 22 l|-0 9 230 bj, Gly Msg CS 14-2 23 51 2 230 50 3. The inheritance of yellow endosperm color is more complex than has been generally believed. Evidence is available for the presence of at least one gene in addition to Y^ and Y-, which is concerned with the presence or absence of yellow endosperm pigment. Ratios of 9:7, 15^1, 19 and others possibly more complex have been obtained. The yellow scutellum gene sy is able to produce its effect in the presence of y-^v^, but in the presence of other recessive whites the development of pigment (carotin) is completely suppressed. The factor or factors involved have not been completely identified. G, F. Sprague John Innes Horticultural Institution, London, England - 1. Experiments on the inheritance of quantitative characters commenced by Dr. Brieger were continued during the summers of 1936 and 1937* The ultimate aim is to produce varieties of sweet corn which are early enough for the English climate and yet satisfactory in yield. In a comparison of Fp families and their parents it was found that the application of a pseudo-factorial method of analysis (Yates, 1936) is not warranted for field trials with maize. The efficiency of the experiment when treated as a 3 x 3 x 3 pseudo- factorial arrangement was about 60$ of that when treated as a simple randomised block lay-out. C. D. R. Dawson’ Connecticut Agricultural Experiment Station, New Haven, Conn, - 1. The evidence so far obtained indicates that mosaics in maize are due to losses or rearrangements of chromosome fragments rather than to somatic crossing over as Stern finds for Drosephila. Paired mosaics involving different chromosomes have been found for nearly all of the easily identified endosperm characters. In seeds heterozygous for C and Pr the following results have been obtained: White Spots Red Spots Rod and White Paired Spots ) Number g^09 1061 37 Ratio 227 29 l 207 These figures indicate a more or less random exchange between the 60 chromosome arms in this triploid tissue. The secondary paired mosaics (twin spots within the dark part of primary twin spots) can not be accounted for by somatic crossing over but are understandable on the basis of translocation followed by further breaking at other places. Variegated waxy tissue in areas that have previously lost the C gene show an unstable condi- tion that would not be expected from somatic crossing over. Similar variegation has been found involving C, Pr, and Su. In seeds resulting from the pollination of C wx by c Wx light and dark aleurone twin spots were found indicating a shift of one C allele. If this resulted from an exchange of homologous segments the endosperm underlying the dark part of the twin spot should be waxy. In many such twin spots examined no waxy areas were found. D. F. Jones Agricultural Experiment Station, College Station, Texas - 1. The most important development in Texas during the past year is the discovery that the essential differences between Zea and Euchlaena are not due to numerous genes scattered at random over all the chromosomes as we first thought, but are due to four chromosome segments which are transmitted in inheritance in almost the same manner as single genes. The fact that these segments all carry genes similar to those possessed by Tripsacum, and the simul- taneous discovery that short segments of the chromatin are inter- changed between Zea and Tripsacum in hybrids of these two genera, has led us to the conclusion that teosintc is nothing more than maize with several translocation segments from Tripsacum superim- posed upon the maize germplasm; the product of a natural hybrid between Zea and Tripsacum. Two of these translocation segments have been located by linkage studies. They occur at opposite ends of chromosome 4 and both show linkage with Su and Tu. These translocation segments from Tripsacum are probably the cause of the unpaired terminal segments which Longle3' has observed in his cytological studies of the hybrid of maize and teosinte. We have verified his observa- tions on the occurrence of these segments but we are not yet certain that they occur in every case on the chromosomes which he has designated. The differences between the various kinds of teosinte which have been collected in Guatemala and Mexico may be attributed partly to the differences in the maize to which these transloca- tions segments have been added, and partly to a loss of portions of one or more segments as the result of repeated hybridization with maize. These new facts reopen the entire question of the origin of 208 maize. With teosinte as a recent development out of the picture, it is’reasonable to assume that maize originated from pod corn, which in the homozygous condition is frequently a perfect flowered plant similar to the Andropogonae, and which has the essen c th ia ar la c t e r i s t i c s of a plant adapted to survival in the wild. The place of origin was probably in South America, either in Peru or Bolivia. V/e suspect that the crossing of South American types of maize with Tripsacum to produce the new genus Euchlaena, has also re- sulted in some new types of maize previously not in existence, such as the pointed pop corns and the long slender flint and^flour corns, neither of which are known in Peru or Bolivia. If this is the case most of our North American maize varieties, with the^ possible exception of the Southern Oourd-seed types, carry Trip- sacum genes in their germplasm. It is possible that the knobs which many of our North American corn exhibit on the chromosomes have been received from Tripsacum via Euchlaena, in which case we are quite likely to find some South American varieties which are lacking in knobs. These hypotheses suggest a number of genetic and cytological tests which will keep us well occupied for a number of years. We are having some difficulty in locating viable seed of Bolivian and Peruvian maizo and if any of the readers of this letter have such seed available we should appreciate receiving some of it. P. C. Mangelsdorf and R. G. Reeves Iowa State Colloge, Amos. Iowa - 1,’ The following linkage data were obtained from the back- cross: + + Kn b —r —bm xQ br fl kn 1'll̂ _ 0 _ 1 2 _2_ 1,2 i U 2x3 1 165 132 lM- 4- 50 50 47 52 ' 10 1 2 16 32 6 2 3^7 IS 100 17 3 4g g 2.S$ 15.6# 15.5$ 2.7^ 0.5% 7 .5$ l,yt> Recombination percentages: br-fp 7*2, br-Kn 26.1, br-bmg 3l>2, f-L-Kn 27.0, Kn-bm2 24,1. These data do not agree completely with the present accepted loca- tion of br and fp. On the basis of those data Kn is located closer to br than to f^ but it must be between and bm2» After more extensive tests in 1937 the writer is doubtful that homozygous knotted plants can be distinguished from the heterozygous plants, 2. A tall late type of plant with about 50 per cent more nodes than the normal was discovered among the plants from an F2 selfed 209 1—1 par from the Krug variety. Plants of this type were crossed with seVeral normal stocks in 1936 and the Fx progenies were grown in lajjt All of the F, plants were normal. A similar type was found in 1936 among the plants from another F2 selfed ear from the Krug variety • A. A. Bryan California Institute of Technology, Pasadena, Calif. - — l7 Correlation "between cytology and map position in chrom. 1. Cytological Linkage Map Position_ Position Tl~2c s .7 near sr T1-9C S .6 near P Tl-2b s A P + 1.5 Tl-6c S .3 P- 7.6- T - br Tl-3a s .25 P- 17.3-- T - br Tl-9a P- 20.0-- T •- 3^ br Tl-9b F- 2B.6-- T - 32,A - br Tl-5c P- 24.2-- T - 27. - br Tl-6b L .25 P- 39.0-- T •- 3.A - br Tl-6a L .2 br - 13.A - T Tl-3d near br Tl-7c L .3 near br ( + 2,7 ) Tl-7a L .4 near br Tl-lOa L A near br Tl-7b L .6 near br Tl-9^ L .6 br + 7.0 Tl~2a near ad and an Tl-5a br - 9.7 - T - 39* " t>m2 Tl~4a br - 20. - T - +5. - bm2 Tl-7d L ,g> br - 3^.7 - T - 18. - bm2 2. Chocolate. In the distal part of long arm of chrom. 2. Homozygous long inversion gave the linkage order: v^-32~B-2p-Ch As the inversion includes about k/^th of the long arm, Ch must be very near the end. E. G. Anderson 3. MspQ. Backcross tests with the following chromosome alterations show no obvious linkage: Inversion of chrom. 2 (near B and beyond v^) TB-^b (2 near vjj., k beyond gl^) T2-3C (2 near sk, 3 near d^) T^-Ba (4- near su, & near spindle attachment) 210 +. Correlation between cytology and map position in chromo-1 some 2. Cytological Linkage Map Position __ Position T 2 - 3 a nes-r Ig T2-6b S .75 3 + 2.2 T 2 - 9 a S .65 3 - 2.7 - T - 23.7 - vl+ Tl-2b S .6 (?) B - 5.3 - T - 30.9 - v\+ T 2 - 3 ° 3 - 6.0 - T - 23.0 - Yk T2-3d B- 13.3 - T - 12.1+ - T2~4d B- 18.0 - T - 6.0 - vi+ T2~9̂ s .1 3- 22.5 - T - 7.2 - v>+ T 2 - 9 a L .1 B- 25.6 - T - 7.0 - vi! T2-7b L .25 B- 28.2 - T - 4-.6 - v^ T2-10a L .2 B- 36.R - T - 6.0 - T 2 - 6 c L .3 Vh + 1.1 T 2 - 7 a L .3 vtt + 1 T2-^a L .3+ V [, ± 1 T 2 - 7 c L .3 V)i + 1.6 T2-5b v£ ± 5.3 T 2 - 4 b L • 6+ va ± 7.7 T2~]+c va ± 35.0 T I. M. Clokey and E. 0. Anderson 5. Linkage of sb. Slit blade is probably not on chromosome where :first reported: Gene s Phase XY XY xY XY Total Re comb Yx Sb RS 930 2^9 306 1569 50 PI 3b RS 1+76 135 154 ^9 316 1+3 Su2 Sb RS 396 265 3 l+o 63 1569 ^3 Py Sb RS 1165 32s 352 63 1913 50 The Y was not certainly, but probably, Yn , In any case, sb is not between and py. 6. Sb is not on chromosome 2. C-enes Phase XY M xY ZY Total tfo Recomb Lgx Sb RS 233 95 76 35 kSk 50 Crip Sb RS 233 92 73 36 1+91+ 50 sb x trisorne 2: Sb sb Culture 1 6 3 Culture 2 137 63 Culture 3 126 20 319 36 211 Tf, were on chromosome 2 there should be about 30 sb plants; if on some other chromosome, about 100. I'jotes: Sb is generally readily classiliable, though quite triable. Many of' the plants are fully fertile. Usually the Iftio is about as expected, though in two of my cultures the ratio 30 nbout J3:l (FP seed). This was not due to lethalness of sb, for nearly all of the seeds grew. In A B PI plants the slitting of the blades seemed less developed than in green plants. J, Shafer University of Wisconsin Madison, Wisconsin ---- 17 Linkage of ra2. Phase XY Xy xY M Tot 3.1 $ Re comb. Genes Cr̂ Ra2 RB ll 26 22 3 65 26.1 This is further evidence indicating that the ra2 locus may be near that of R. A. Brink Arlington Experiment Farm. Arlington. Virginia, - __ --- 1. The dominant Dt gene has been reported (1936) to produce dots of aleurone color on a^-tester seeds. The nature of the interaction between Dt and a-j_ was unknown at that time. It has now been established"that Dt causes ai to become unstable and to mutate at a rate thousands of times greater than normal. Muta- tions of a-i in the presence of Dt can be detected in aleurone, husks, and leaves i.e. plant color, and pericarp tissue. Reces- sive a1 mutates to the _AX allele a thousand times as frequently as to the aj allele. There is no chromosome abnormality present in the Dt line. The a^ gene is in chromosome 3 while Dt may belong to chromosome 9. Mutations of ax to Ax or aj occur late in devel- opment in all tissues. It is not possible, at least by the writer, to reconcile these data with any of the hypotheses advanced by Schultz, Stern or Patterson to explain variegation. They seem, however, to agree with Demerec's conception of increased mutability being caused by a chemical or physiological condition produced in the cell. Recessive a.-̂ is highly stable in the presence of dt. The Dt gene is specific in its effect on a^» Uo other recessive locus including a2, c, r, lg-^, wx and su is affected. A dominant modifying gene reducing the frequency or rate of mutation has been isolated. There is some evidence of a recessive gene affect- ing the time of mutation. 2. The following data on the location of ws-̂ show the order to be as follows: ws^ lgx gl2 B 0 IT 30 19 These four genes are all located in the short arm of chromosome 2 and if the Rg or r& alleles are used with B all of them can be classified in the seedling stage. 212 WS3 lg]_ + - i-J-15 WS7; igi gi2 - 16 + + + — 1063 WS,lgl+ + + gl2 - 5 3 3 selfed + + gl; WS3 + gig - 2^ WS7 + + 90 + lg-Ĵ + - 99 + lgx gi2 - If Total = 22^1 WS7 lg]_ == H i° ws3 S^2 = igx - gi2 = 19% 3, Trisomic tests show is in chromosome 6, Since v ^q gave ^3io recombination with it will fall near the end of either the long or short arm. Tests with joy will be made this spring. if. Preliminary results indicate that the pollen tube is not parasitic but is dependent for its growth in the silk upon the starch stored in the pollen grain. 5. There is a highly significant increase in crossing over in the Ag-Bt and Bm-g-Pr regions of chromosome g in microsporocytes as compared with megasporocytes. In a Hlow” line there was 7 re- combination between Ag~Bt in the female gametes contrasted with 12.2$ in the male gametes. Similar differences between the fre- quency of crossing over in the two sexes is the explanation of the inexplicable difference found by the writer (1936) in crossing over for the Bm-j-Pr region in plants hyperploid for the short arm of chromosome 5 as compared with diploid sibs. The hyperploid individuals had been used as the male parent while the diploid sibs had been used as the female. M. M. Rhoades Cornell University. Ithaca, New York - 1. In the News Letter of March 23, 1937? PP* 1? 2, it was shown by means of three-point tests involving the genes sr, P, and br and the translocations Tl~5a and Tl-pc, that the order of the genes is sr - P - br with the translocation breaks between P and br. Backcross data from ^76 individuals were also presented sug- gesting that ts0 is between P and ^hat was then called Tl-lOb but now designated Tl~2c. Records of the past summer presented below show that Tl~2c is to the left of P very near sr, that ts0 is to the left of ? with ms-̂ y presumably to the left of ts2 , an& that Tl—3a aad Tl-9c are probably to the right of P. The data are as follows: Genes Phase XY Xy xY xy Total $ Re comb. Sr Tl-2c C3 151 1 l H 297 0.7 213 Fj genotype 0 1 2 ij_J Total tsp P + 76 93 1 2 17 22 0 0 r + Ti-5t> 169 0 211 i > $ 13.7$ ms17 P + 26 25 3 2 15 13 2 1 2g + + Tl-5b 51 5 $75.7 $ 32.2$ ts2 P + 106 i4-o 3 1 29 36 0 0 246 i). + + Tl-3a 0 3151.3$ 2065. 6^$ MS17 P + ^ 33 2 0 7 5 0 0 + + Tl-3a 87 2 12 0 101 2.0$ 11.9$ sr__ P___+__ 38 32 2^ 17 0 5 0 1 + + Tl~9c 70 4i 6 1 117 35.0$ 4.3# 0.9$ From r37 News _2Z 21! 5 129 Letter 167 r? To 7 2 46 26. ii$ ^.1$ 1.6$ Tl~2c + _P 156 132 51 29 2 1 0 0 + ts2 + 23k 50 3 0 377 + ts2 P 201+ 27 6 50 4-9 3 0 0 1 Tl-2c + + It-SO 22 3 1 5^3 m 179 , 6 1 9 60 13.7$ 0.6$ 0.1$ From *37 News 4oi 10 5 0 476 Letter 1175 249 11 1 1J+3 6 1 7. H 0.3$ 0.1$ + ms-jy P 152 157 29 31 3 5 0 4 - 309 60 g 4 3&L 15.7$ 2.0$ 1.0$ Two of the cultures reported above involving Tl~2c with B of data from B Tl-2cl + P + + t s 2 + 0 1 _2 .1 1^2 U 3 , 3 1,2,3 Total 122 111 27 3^ 30 21 2 0 g 21 1 0 0 0 0 0 233 61 51 2 29 1 0 0 377 16.2$ 13. 5$ 0.5$ 7.7$ 0.3$ 0 0 One of these cultures also segregated Ig^ as in F2. Using only Igp plants, the records for lgp B Tl~2c + P are: + + + t s p + 214 0 J L _ 2_ 4 1,2 1 U 2 U 1,2,3 Total 2$ 15 12 10 0 6 3 1 ^ „ 79 19.0# 15.2$ 12.7# - 7 M 1.3$ 5.1# One of the cultures reported above to show close linkage between T1~2c and sr also involved B of chromosome 2 but no marker other than sr of chromosome 1. The data are: Fl genotype 0 1 2 1)2 Total R Tl—2c + 63 2S 9 0 0 0 0 f + sr 107 37^ 0 0 l H 25.7$ 0 0 Since no crossover between Tl-2c and sr appeared in this culture, the orientation of these two markers with respect to the rest of chromosome 1 cannot be told. 2. Among 2052 F^ plants of crosses of ad ̂with an^, no double re c e s s iv e appeared, but cultures from 220 p£ an-j_ and ad]_ plants indicated a crossover value of 4.1$ (Linkage Summary, 1935) P* 32). Backcross cultures of last summer gave the following results: Genes Phase XY Xy xY XY Total fa Re comb. Ad̂ An-ĵ CB 2^7 7 10 199 463 Ad1 An1 RB 36 31 1 _Z2 535 4.1 R. A. Emerson 3. Chromosome 7 • F]_ genotype 0 1 2 1,2 Total in + + SSO 30 g 1017 + V5 S1! 3*4$ 11.316 0.9$ in - k. 3 - v5 - 12.2 - glx in glj_ + £1 12 23 7 123 + + id 9.S$ lg.7$ 5.7$ in - 15 • 5 - gli - 24.4 - id A number of seedlings in the latter cross were destroyed by mice in early stages. Counts are not dependable for distances but they are consistent with the order in the first cross. A. C. Fraser 215 !(-. Doubling the number of chromosomes in yellow corn increased the carotinoid content 4-3 per cent as determined by chemical analy- sis of 2N and 4-N stocks having a common origin. The volume of the endosperm cells of the tetraploid was more than 3*5 times as great as that of the diploid. Thus the individual endosperm cells of the tetraploid contained more than 5 times as much carotinoid as did those of the diploid and in terms of gene concentration within the endosperm tissue the amount of carotinoid was increased 2.5 times as a result of chromosome doubling. Chemical analyses by D, B. Hand. 5, The following results have been obtained to date on haploid frequencies in seedling progenies from untreated and x-rayed (1500 r-units) pollen: N 2N IS /( 0 From untreated pollen 66 126,302 From x-rayed pollen 31 2k , 619 t.as/ 0 e 0 The haploids were identified with the aid of recessive seedling genes, stomate examination and root-tip chromosome counts. L. F. Randolph 6. The following characters have appeared in inbred lines: co —Corrugated leaf. Raised striations of tissue in seedling and mature leaves. Classification good. Viability normal. bkx-Brittle stalk. Similar to brittle stalk-1. Classifica- tion good. Viability normal. dea-Defective endosperm. Seed similar to de^. de^-Defective endosperm. Seed similar to de^. dec-Defective endosperm. May be a new sugary. Classification good. Viability good in germinator, but hasn’t been tested under field conditions. fx- Fine stripe. Plant striped in seedling stage and through- out development. Classification good. Viability normal. Pux-Purple plumule. Similar to Pu^. wx- White seedling. Similar to w^. wsx-Fnite sheath. Similar to ws7. R. G. Wiggans 7. White seedling-1 (w^) has been known to be loosely linked with the gene of the sixth chromosome (Linkage Summary, 1935). To place w^ more accurately in the chromosome seedling counts were made of the F^ cross between w^ and pigmy (py). Seeds were taken from the Co-op stocks. The results indicate a very close linkage between py and w-,. 216 genes Phase XY Xy xY xy Total ^ Recomb. Py Wx RS S67 ^16 ^+3 0 1726 ty-.$(if one xy) G. A. Lebedeff Segregation in autotetraploid maize. To determine the nature of segregation of some genes in autotetraploid maize, back- crosses were made involving the genes B(plant color booster) and Su(sugary endosperm). Cross B b No. of Ratio Plants BBbb x bbbb U 7 135 572 3.25 : 1 Some difficulty was encountered in classifying the progeny of the backcross, sun red (BBbb) x green (bbbb), since there was a great deal of variation in degree of coloration. Some plants were dis- tinctly sun red, others resembled dilute sun red, while still others showed a tinge of color on and around the ligules. Un- doubtedly errors were made in classification, there^being an excess of green plants. However, the backcross ratio approaches 3.6/ :1. Since the type of segregation is a function of cross over distance between the gene locus and the spindle fiber attach- ment region, this would indicate that the gene 3 is located fifty or more units from the spindle fiber attachment region and that chromatid segregation had occurred. Cross Su su No. of Ratio plants Su Su su su x su su su su 2877 6*15 3522 ±.k6 : 1 su su SU SU X - Su Su su su _3Z b.2k : 1 32S5 732 y m kA} : 1 There was no difficulty in classifying sugary segregates in a backcross of autotetraploids. The ratio of 4.^3 Su~: 1 su indi- cates that this gene has segregated on a basis intermediate be- tween the random distribution of four chromosomes and random dis- tribution of eight chromatids, and suggests that the gene Su is located about 20 cross over units from the spindle fiber attach- ment region. H. E. Fischer 9. It has been observed by many investigators that the F-j_ ears of maize-teosinte hybrids are 4-rowed (paired spikelets, two-ranked). This indicates that the paired spikelet condition 217 of the maize ear is dominant to the single spikelets of teosinte. Collins and Kempton, 1920, showed that in an F2 population, paired and single spikelets segregated 3:1. Data obtained by the writer in the summer of 1937 have confirmed their findings. It has not been pointed out, however, that the two-ranked condition of teosinte, which appears in the Fp of maize-teosinte hybrids, segregates as a unit character in the F2 population. The combined 3:1 segregation of the dominant two-ranked condition of teosinte (as contrasted with the many-ranked condition of maize) and the 3:1 segregation of paired vs single spikelets, gave a 9:3:3:! ratio, indicating that these two genes are independent of each other. This independence makes possible the combination of the recessive many-ranked condition of maize with the recessive single spikelets of teosinte, giving two kinds of ears: some with an even number of rows and others with an odd number of rows. Thus, 3-, , and 5~t o w q <1 ears with single spikelets have been found. With paired spikelets these would presumably have been 6-, and 10-rowed ears, respectively. 10. Preliminary Fp and reciprocal backcross data on maize- teosinte hybrids indicate that response to short-day may be due to one, or a few, genetic factors. 11. New characters. gc2 - Glucostacious-2. Seedlings pale green in very early stages. Then brown blotches appear and the plants die. Chrom. Unknown • czx - Cuzcoid. Plant too late to shed pollen under field conditions at Ithaca. lap - Lazy teosinte. Similar to lap in maize. Has not been tested for allelism. D. 0. Langham II. Seed Stocks Grown, 1937 1. Testers. Chromosome 1: p adp seg. anp P/ + f̂ bm2 seg. br (p adp x p adp anp)self sr an^ bm^ br fp bm2 x (Kn x br fp bm2) Chromosome 2: lgp gl2 B tsp V]p A PI x Igp +/gl2 B +/tsp vip A PI Ig-̂ b gs2 V^/ ? 012/ ? x Inbred II lg1 012/ ? b v]+ gs2 x Inbred I 218 Chromosome 2 (con't); Inbred x lg1 gl2 b v^ A pi b gs2 lgx lg-ĵ gl2 b V[| Y trisome #2 Chromosome 3 : . ai lg2 Dt/? ax na cr gl1 v^ Y ax Dt/? ax Dt/? seg. lg2 an +/na +/lg +/tsi| x ax na +/lg2 +/ts2 a^ lg2 *̂1 x 1^2 ^ Ax lg2 +/d1 x Ax lg2 ts^ d^ a-̂ lg2 *̂a2 a1 lg2 Dt/? y1 seg. na a-] yt seg. na na tsi| x na +/tsi|_ tsij. +/na Dt/? x a^ +/ts^ na Dt/? Trisome #3 Chromosome ty-: (su-̂ x djj) x (Tu su-|_ x djj) (gl^ x su]̂ j2)self suam du (Ga x su^)self (+/wi|. +/su1)self (su^ gl^ x wl)self (Ts^ su ̂ x wl)self (Ts^ su-̂ x la su^Jself (Ts^ su^ x la) x la sn^ Trisome #4- Chromosome 5 : Homo. Ax C R a2 bt bv prx Homo. Ai C R a2 bt bv pr1 seg. Vp v0 ap A-̂ C R b pi Homo. Ai C R Ap bt bv pr ]_ Trisome #5 Chromosome 6: PI sm +/py A b x PI py A b PI sm x pbx (Lebedeff) Y^ PI sm seg. py Chromosome 7 • Inbred x ra^ gl^ ij blx rax glx ij x bd1 rax gl-L i j x glx ij frx +/fr2 ral g1! ij glx Tp seg. rax tp (bdx x glx ij) x glx ij bd1 rax glx x Tp glx v^ Trisome #7 219 Chromosome 8 : vx6 msg 21 x (rnsg x vl6; rnsg jp x rnsg/+ jp msg x msg/+ Trisome #3 Chromosome 9 : Inbred I x gj| wx Inbred I x ar wx g^ wx x (gl4. x yg2 c sh wx) c sh wx bp au-̂ au2 sh msp x ms2/+ wx da ar sap (gill x yg2 c sh wx)self Trisome #9 Chromosome 10: r zb^ seg, nip ±1 seg, w1 0g/+ Y Pwr Og Og Inbred x OgOg seg, Ip r Ap C y1 seg, gp Trisome #10 2, Miscellaneous u, s . 20^ (Inbred West Branch (Inbred II) Inbred I x bm^ seg, hf A1 C R PI B Yp 9-2 Kn A1 +/b PI x Ax +/b PI 2 1 b PI Ai C R A2 Prpg A seg. v12 (bm^ x yg^)self Ap C R A2 prp i v13 va2 x va2/+ Vg/+ x vg wa x wa/+ an2 x Inbred ms^ x ms^/+ +/na2 x na2 ms6 x msg/+ r prp x Ap C B ms 7 x msy/+ ApB pi Rst x r prp ms<2 x ms^/+ +/bkp x bk2 msio x msio/+ (+/bk-j )self ms12, x ms12/+ +/de +/mi x de mi 220 ms-^ x msiy + +/an2 x +/an2 ms-ĵ x ms-Li|/+ Inbred x mi ms^y x ms^y/+ Wc Y-l msy<̂ x mGy^/+ fx (Wiggans) msj|p x ms^2/+ dea » v12 x v12 deb ■ prl seg. gl1Q de0c n (sb x A1 b pi +/Y]_ su2 )sib CO » y1 su? seg sb wsx " Pb̂ . Chlorophyll types- Yellowish green Sx sy rather It. green Pcx medium to It. green Ch/? seg* glx dark g2*een TS3/+ vi|/+ x Rg/+ nip TS3/+ v^/+ X R g]_ C sh wx gc2 Seed stocks from Australia grown by Shafer in Calif, for the Co-op: 3 different stocks of yellow-striped seedling. 5 different stocks of virescent seedling. crinkly. 3, Stocks too late to mature at Ithaca. From Krug: brown pericarp black pericarp branched ear seg. tassel seed seg. dwarf bract in tassel oily spots seg. defective endosperm seg. mealy rolled leaf variegated pericarp semi-dwarf ragged striped leaves seg. zebra seedling ms x ms/+ crinkly zebra leaves From Mangelsdorf mottled dwarf seg. vpx 221 lg. 4. No germination, sr an-j bm2 Jjjax A c R sh wx B pi da aup au2 sh +/v!5 x + ^ 5 ms[|. x ms]|/+ rnsp̂ x msp^/+ mSgy x ms2y/t gl+ ar sap pkp III. Seed Stocks Received For Propagation in 2 2 1 $ 1. J, Shafer, Ithaca, N# Y. :~ V19 T 1— 2b x T 1- 2b T 2-* 4b 2. R. A. Brink, Madison, Wisconsin:- (pm x lg2 dp) sib (Ap pm x ap lg2) sib 3. J. H. Kempton, Washington, D. C.:- fs 4. A. Tavcar, Zagreb, Jugoslavia:- Hs 5. M. M. Rhoades, Arlington, Virginia:- (ws^ Igp B Ax pi x gl2) x (ws^ lgp b Ap pi x gl2 ) 6. W. R. Singleton, New Haven, Connecticut:- ra2? zbx f x ys su-̂ x +/lo +/bax v57 gl, X lg! gl2 b VI; r^ACYSu yellow x yellow ysx (7 cultures) 7. R. Cr. Wiggans, Ithaca, N. Y.:- dec ^ x IV, Miscellaneous Co-op Items 1. Seed stock inventory. In March, 1937? an inventory of the genetic seed stocks in the Co-op collection showed that l4$ of the genes reported in the Linkage Summary, 1935? were not in the seed trays here. A list of those l4?> genes was included in the News Letter, March 23, '37> and several maize geneticists responded by sending in 16 genetic stocks. 222 In January, 193$, personal requests were sent to each of the pc geneticists who, collectively, had first reported the remaining 132 stocks. We have learned that about 75$ of those genes have been lost due to inviability of seed stocks. 2. Assignment of linkage groups. One of the topics discussed at a special meeting of maize geneticists at the A A A S meetings in Indianapolis, was the problem of linking workable genes and developing more desirable tester stocks. This is an important Question because there are more than 50 suitable genes that haven’t been linked and some of the chromosomes are poorly marked. The plan previously outlined for linking new genes has not been fundamentally changed, but it may well be reviewed here. Each of the ten linkage groups in maize has been assigned to one, or more, cooperator who is charged with testing unplaced charac- ters with his particular chromosome and building up suitable tester stocks. The following assignments have been made: Chromosome 1. Emerson. Chromosome 2. Rhoades and Clokey. Chromosome 3. Brink and Woodworth. Chromosome 4. Singleton and Brunson. Chromosome 5* Burnham. Chromosome 6. StadLler and Lebedeff. Chromosome 7• Jenkins and Fraser. Chromosome 8. Sprague and Perry. Chromosome 9* Eyster and Shafer. Chromosome 10. Lindstrom, Wentz, and Bryan. When a new gene is found, a few seeds involving it should be sent to the secretary of the Maize Genetics Cooperation who will grow them in an increase block and obtain a liberal supply of seed for the central repository. Then the secretary will send a few seeds to each of the above geneticists who will test for linkage in his particular chromosome. This system has been devised not to limit the number of workers who are trying to link new genes, but rather to insure the linkage of every workable gene. 3. More vigorous genetic stocks. During the summers of 1935 and 1936, a number of maize geneticists tested a group of inbred strains for disease resistance and general desirability. The two^ inbreds, U.S. #20^ and West Branch Sweepstakes, seemed best suited to Ithaca conditions and have been selected for use in the Co-op. They have been designated as Inbred I and Inbred II, respectively, and are being used in crosses with weak genetic stocKS to increase vigor and, by repeated backcrossing of the segregates to the 223 inbreds, to obtain a more nearly homozygous chromosome complement. Later, the segregates from each inbred line may be crossed to get hybrid vigor. Last summer 17 genetic stocks were crossed with both Inbred I and Inbred II* 1|. Linkage maps. The linkage maps attached to this Letter were prepared from the data in the Linkage Summary and the data which appeared in the Co-op News Letters since the Linkage Summary was published. Sincerely yours, S). to. £33, p p . 3, 6 1-23- 3 3, pp. 3 . 6 3-6-35, PP* 1, 3, 4- 3-6-35, p p . X, 3 3-11- 36, pp. 11, 15 3-4-36, t). 10 3-23-37, PP* l^> 15 3-23-37, p p . 3, 5 3-6-33, pp. 6,7,3,10,11,13,14- 3-6-3S, pp. 1 , 5, 6, 14 ba-j_ * I- 25-34-, p. 5 12-10-33, P. 5 II- 24-34-> p. 13 11-24-34, p. 6 1-23-33, P* 3 Bri]_: ba^: I- 25-34-, p. 7 1-25-34, p. 4 II- 24— 34, pp.6 , 7 1- 23- 3 3 , p . 6 1-23-33, PP* 3, 7 3- 23- 3 7, p. 1 3- 4- 36 , p, 7 bd: bn2: 9-13-3^, PP. 6, $ 9-13-34-, p. 3 11-24-34-, p. 10 3-4-36, pp. 7 , 16 bp: 3-23-37, PP. l, 9 3—6— 3^, p. 15 1-25-34-, p. 3 1-23-33, P. 7 be (=bd): 3-6-33, p. 16 9-13-34-, p. 3 br: Bh: I - 2 5 -3 4 , 4 I I - 24-34, p. 5 1^25-3^, p. 6 1-23-33, pp. 3, 7 1-23-33, P. 6 3-6-35, P- 3 3-4- 36, p. 10 3-23— 37, PP* X, 2, 5 3-6- 30, pp. 1,5,6,9,14 3-23-37, P. 1 btl : brn̂ : 12-10-03, PP. 3, 5 12-13-73, pp. 2, 5 I- 25-34, p. 6 I- 25-34, p. 6 II- 24-04, pp. 2, 4, 4, 6 I I - 24-34-, pp. 2, 4-, 5, 6, 7 1-23-33, P. 7 1-23-33, PP- 3,6 3-6-35, P- 3 226 >1^-36, PP. 7, 14 1-23-33, P. 7 3~23~37 > p. io 3—6—3S , pp. 9, 15 da : b%(= bt1): 9-13-3*+, p. 2 3—6—353 p. 3 V bv: 9-13—3^, P. 2 3.2-1^33, P. 5 dH : I- 2^34-, p. 6 I I — 2U— 3*4-, p. 4 3-6-33, p. 15 1-23-33, P. 7 3-6- 3$, p. 15 d ?: 3-23-37 12-l$-33, pp. 2, 6 dl : 1-25-34-, p. $ 9-13-34, p. $ I- 25-314 p. 5 1-23-33, PP. 3, 7 II- 2l!-3l4, p. 12 3-6-35, PP. 12, 14 1-23-33, P. 7 3-4-36, pp. 1 1, 15 3-6-35, P. 5 3-6-3$, p. 16 3-4--36, p. 9 3-23-37, PP- 5, 114 cb: 3-6- 3S, pp. 6 , :, 15 I- 23-33, P. 7 d2 : Ch: 12-13-3 3, p. l 12 16 1-25-3*+, P. 5 - U 33, p. 3 II- 24-34, pp. 6, 7 d3: 3~4~36, pp. 3 , 17 3-23-37, P. 5 1-25-3*+, p. S 3-6- 3$, p. 6 1-23-33, p. 7 c o : d5; 3—6—35? p* 15 1-23-33, P. 7 c r^ : d6: 1-25-3*+, p. 5 1-23-33, P. 7 1-23-33, PP- 3, 7 3—14— 36, p. 7 3-23-37, P. l*+ d7 : 3—6— 3S , pp. S, 15 12-13-33, p. 1 227 2k. 1~25~3^, P. 2 3-23-37, P. 13 9~ lJr-3k, P» ̂ 3-6-33, p. 15 3-23-37, PP. 3, 9 et: d&l« 3-6-35, P. 5 1—25—3^ > p* $ 1-23-33, p . 7 3-6-35, p. 12 3-6-3&> p. 16 1-25-34, P. 4 n-24~34, pp. 5 , i3 Da 2« 1-23-33, p p . 3, 8 3- 6- 3 5 , P > 1 12-1^33, P* 6 3-23-37, PP. 3, 9 , 9-13-34, p. g 3-6-3 2, pp. l, 5 , l4 de 7: f 2 = 3-6-35, P« 12 1-23-33, p. S de^ • f3: 1-23-33, p. S 1-23-33, P. 8 3-6-35, PP. 9, 13 del: f ia : 1-23-33, p. 7 9-13-34, P . 3 del5: fi: 1-23-33, p. S 1-23-33, p. 8 del6: fli: I- 23-33, P. « 1-25-34, p. 4 dl: 1-23-33, P. 8 3-4-36, p. 7 12-13-33, p. 4 Dt: 1-25-34, p. 7 II- 24-34, p. 1 1-23-33, P. 8 3-4-36, p. 7 3-6-33, p. 15 3-23-37, P- S 3-6-33, pp. 3, 15 du: 1-25-34, p. 7 1-23-33, p. 8 3-6-38, P. 15 228 gl]_ (oon't.): gl: i-2>34, p * g 11- 2*1-3*1, p p . 5, 7, 1*1 11- 24-34, p p . 5, 10 3-6-35> P* 1 I- 23-33, PP. 3, «5 3-4- 36, pp. 3, 9, 16 3-6-35, P* 4 3-23-37, PP. 4, 9 3-4-36, p p . $, 9, li, 16 3-6-38, pp. 1 1 , 15 >23-37, PP* 6, $, 9 3-6-3$, p. 16 gl2: g2: 1-23-33, pp. 3, 9 1- 25-3*1, p. 4 12- 13-33> P* 5 3-6-35, P* l II- 24-34, p. 6 3— 4— 36, p. 15 3-23-37, p . 14 3-23-37, P. 8 3-6-38, pp. 7,8, 9, 14 g3: gl3 = 1-23-33, p . 3 1-23-33, PP. 3, 9 g4: 12- 1&-33, P. 5 1-25-34, p. 10 1-23-33, p* & 3-6-35, p. 1 1-25-34, P. 3 3-23-37, PP. 10 3-6-3$, p. 16 3-6-38, pp. 2, 6 , 15 Go*! J gl4: 1-23-33, P. 8 12-IS-33, p. 6 3-6-38, p. 15 1-23-33, P. 9 3-23-37, P. 10 ga2: 3-6-38, p. 16 3—U—36, p. ill gl6 (= old gig): glb: 3-23-37, PP. 9, 10 3-6-38, p. 3 9-13-3*1, P. 3 gig (new) gl0: 3-6-38, p. 3 9-13-3*1, P. 3 g ! 7 e1d: > 6- 3*$, p, 3 9-13-3*1, P. 3 gig-’ gl*: 3-6- 35, p. 2 1-23-33, PP. 3, 9 3-23-37, p. 9 12-18-33, PP. 2, 5 3-6- 3$, p, 3 1-25- 34, p. 7 229 gllO (-g1].): 12-12-33, P.,1 11— 24— 31*-, P. 5 I- 25-34-, P. ^ 9-13- 34, p. 3 9—1>-3^? P* $ 3-6-33, p. 14 II- 24-34, p. 13 3-4-36, p, 3 h : gl1Q (new): 11—24— 34-, p. 3 3-23-37, P. 10 sin • 1-23-33, P. 9 1-25-34, p. 3 3—6— 33, p. 2 3-^36, P. 15 3-6-33, p. 16 6°as ij: 3-6-35, P* 6 1-23-33, p . 9 Srae: 12-13-33, p. 6 I- 29-34, P . 7 1-23-33, P. 9 II- 2^34, pp. 5, 6, 7 , 10, l4 3-6-35, P. 1 gm2: 3-4- 36, pp. 3 7 , 9, 16 3-23-37, p p . 4, 9 1-23-33, P. 9 3-6- 33, pp. 11, 15 gra2?: in: 3-6- 35, P. 13 1-23-33, P. 9 12-19-33, P. 2 g®3?: 1-25-34, p. 7 3—4— 36, p. 16 3-6-35, P. 13 3-6-33, p. ll gmij.2 it: 1-23-33, P. 9 3-4— 36, p. 9 gs?: h : 12-13-33, p. 5 1-23-33, PP. 3, 9 1-25-34, p. 7 g!i; 3-6-35, p. 4 3— li— 36, p. 14 1-23-33, P. 9 3-23-37, P. 6 1- 25-34, p. 4 3-6-33, pp. 2, 3 , 15 3-23-37, P« 6 gs2: 12-1&-3 3, p. 1 12-13-33, p. 6 1-25-34, p. 5 9-13-34, P. S 230 jp Ccon11,): le: 3-6-35. P* 2 9-13-34-, p. 3 3-6-33, P . 15 3-6- 35, p. i4 Kn: lgl = 3-23-37, P. 9 , 1-23-33, p p . 3, 10 3-6-33, pp. 5, 14- 12-18-33, p. 6 1- 25-34, p. 4 l7: n-24-34, p. 5 3 6 35 3-6-35, PP. l, 2, 4- - - , p. i4 3-4— 36, pp, 15, 16 3-23-37, PP. 7, 8, 14 h : 3-6- 32, pp, 7 , 2, 9,10, 14 1-23- 3 3, p . 10 3-6- 38 !g2:, p. 16 1-23-33, P. 10 12: I- 25-34, p . 5 I I - 24-34, d . 12 1-25-34, p. 2 3-23-37, P. 14 1-23-33, P. 10 3-6- 32, p. 15 14: li: 1-23- 3 3, p. 10 10 1-25- 34 2 1-23-33, P., p. 1-25- 34, P- g 3-23-37, PP«. 8, 9 15: °1 : 1-23-33, P. 10 12- 12- 3 3, P., k I-25-34, P. 5 11-24-34, P., g 1-23-33, p. 10 9-12- W , P* g 3-6-35, p. 1 I- 23-33, P. 10 3-6-35, P. 11 12: lp: II- 24-34, p. 2 3-4— 36, p, 2 I- 23-33, p. 10 3-23-37, P. 8 me: lai : 12-12-3 3, p. 4 12-12-33, PP. 3, 5, 6 II- 24-34, p. 2 I- 25-34 p. 5 I I - 24-34, p. 10 Mi: 3-23-37, P. 6 3-6-38, p. 15 231 msi: nl-, (con't.): 1-23-33, P. 10 I- 25-34, p. 8 3-6—38, p. 16 msg • nlo) 1-23- 33, p. 10 1-25-34, P. 8 12-18-33, p. 2 3-6-35, p. 12 II- 24-34, p. 18 3-6- 38, p. 16 °1 : ms^: 12-18-33, p. 4 1-23-33, p. 10 11-24-34, p. 8 1-25-34, p, 5 3-4-36 msg: °2: 1-23-33, PP. 3, ll 12-18-33, p. 4 1-25-31!, p. 7 11-24-84, p. 8 3-23-37, P. 6 3-4-36', p. 9, 3~6~ 3g, pp. 2, 3, 16 3-23-37, P. 4 ms1?: 03 (=0l): I- 23-33, P. 11 12-I8-3 3, P. 6 II- 2^34, p. 3 9-13- 34, p. 8 3-6- 3$, p* 10 3-4- 36, p. 9 niS]_g: Og: 1-23-33, P. 11 11-24-34, p. 10 3-23-37, P. 6 ms 20 2 3-6-38, p. 16 1-23-33, P. 11 oy: 3-6-3^, P* 6 1-23-33, P. 11 Mt: 3-6- 35, p. 10 1-23-33. P. u na^: 1-23-33, p p . 3, n 12-18-33, p. 4 1-23-33, PP. 3, 11 I- 25-34-, p. 4 I- 25-31). p. 5 II- 24-34-, pp. 3, 5, « II— 24— 34, PP- 11, 3-6- 35, pp. l, 3 3-6- 35, P* 3 3-4- 36,pp. 9, 10 3-4-36, pp. 7 , 10 3-23-37, p p . l, 2, 5 3-6-38, p. 15 3-6- 38, pp. 1,6,9, 10, l4 nlx : pb: 3-23-37, P. 2 3-6-38, p. 15 232 Pc2: pm: 11—2 1̂— 34, p. 5 12-18-33, p. 5 9-13-34., p. S 11- 24-34, p. 12 9-13-3^, P. 3 po: P&?: 1-23-33, P. 12 1-25-34, p. 6 9-13— 3U-, p. 3 3—6—35, pp. 12, 13 Prl '• 3-23-37, P. 7 1-23-33, pp. 3, 12 P£l: 12- 18-33, P. 5 1-25- 34, p. 6 1-23-33, P. 12 pp. 2, 4, 5, 6, 7 1-25-34, p. 3 3-6-35, PP- 1,2, 10, ll 3-4- 36, Pp. 7 , ll, 14 pg2: 3-23-37, p. 10 3-6-32, pp. 9, 15 1-23-33, P. 12 1-25-34, p . 5 Pr2: VSy 3-6-35, p. 12 1-23-33, p. 12 pyi: PS6: 1-23-33, pp. 3, 12 I- 25-34, p. 6 1-23-33, P. 12 II- 24-34, p. 14 3-6-35, P. 4 Pg7: 3-4-36, p. 7 3-6- 3S, pp. 12, 1 3, 15 1-23-33, P. 12 py2= pk: 12-18-33, p. 1 1-23-33, P. 12 1-25-34, p. 8 Pis 1-23-33, pp. 3, 12 12-18-33, p p . 1, 5 1-23-33, P. 3 I- 25-34, p. 8 I- 25-34, p. 6 II- 24-34, pp. 5, 10, 3 9-13-34, p. 8 3-6-35, PP. 3, 4, 9 II- 214-34, pp. 10, 14 3-4-36, pp. 8, ll, 14, 16 3-6-35, PP. 4, 5 3-23-37, PP- 6 , 8, 9 3-23-37, PP. 2, 14, 15 3~6~3$> p. 16 3-6-38, pp. 7 , 15 233 ra?i Hg2?: 3-4-36, p . 7 12-15-33, p p . 3 , Rp: 1-23-33, p p . 3, 12 >6-35, P. 3 12-15-33, pp. 2, 3, 5 > 4- 36, p. 17 I— 25—35-, P* 7 , > 2 > 3 7 , PP. 3, 9 II- 24- 34, pp. 5,6,7,3,10,1^ >6-35, PP. l. ^ „ rt: > > 36, pp. 7, 9, 16 3—23— 3 7, p. ‘J- 11-24-34, p. 10 3—6—3 3, p. 15 sl : rag: 1-23-33» p . 13 12-13-33, P- 5 11-24-34, p. 13 >4-36, p. 7 , > 2 > 3 7 , P. 1*̂ i-2>33, P. 13 >6-33, pp. 1, 3, 15 > 6-3 3, p. 16 re 1: sa 2' > 6-3 5, p. 13 1- 2 3- 3 3 , p. 1 3 rex: sb: 9-1 >34, p. 3 3-^-3^ re2: sca : 9- 1 3-3 4 , p. 9 3-6- 35, P* 5 > 6- 3 5 , p. 1 0 scb : rey 3-6-35, P. 5. 3- 6-3 5 , pp. 1 3 , l4 scc: re^: 3-6-35, P- 5 9-13-34-, p. 9 sc^: RglS 1-23-33, P. 13 1-23-33, P. 12 12-15-73, pp. 3, 5 scp>: I- 25-35-, p. 5 I I — 2 T— 34-, pp. 1 0 , 1 1 , 1 2 , 1 3 12-1&-33, p. 6 3-4- 36, d . 7 3-23-37, P. 1^ 234 sf I sp^ (con1t.) 3-6-35. P- li 3-4-36, p. 8 3-23-37, P- 8 sh: sr: 1-23-33, pp. 3, 13 12-18-33, PP- 2, 6 1-25—31+, p. 4 1-25-34, P- 8 1-23-33, p . 13 3-6-35, PP- 12, 13 3-4-36, p. 10 3-23-37, P- 7 3-23- 3 7, PP. l, 2, 3, 5 , 3-6— 38, p. 16 3-6- 38, pp. 6, 9, io, 1 1, lU- si: s "fc *p • l-25~3^, P« 6 3-6- 35, p. 12 1—23— 33 > P. 13 st: sk: 1-23-33, P. 13 1-23-33. P. 13 I-25-34, p. 5 1-25-34, p. 4 3-6-38, P« 6 su-^: si: 1-23-33, PP. 3, 13 12-18-33, PP* 3, 4, 5, 6 1-23-33. P. 13 I - 25-34, p. 5 1-25-34, p. 7 I I - 24-34, pp. 8 , 9, 10 9-13- 34, p. 9 sm: 3-6-35, pp. l, 2, 3, 11 , 3-23-37, PP. 5,, 6, 1 3, l4 1-23-33, P. 13 3-6-38, pp. 2,4 ,6 ,13,15 I- 25-34, p. 6 II- 2*4-34, p. l4 su2: 3-6-3 5, p. 4 3-^36, p. 9 12-18- 33, p. 6 3-6-3 ,̂ p. 15 > 6-35, p. 11 V23-37, P. 15 sO]_: 3-6-38, p. 7 12-18-33, P. 6 su-̂ : spx: 3-6- 35, pp, 1 1, 12 1-23-33, P. 13 sy: 12-18-33, P. 4 I- 25-34, p. 5 3-6-38, p, 3 II- 24-34, p. 8 9-i>34, P. S th (=sr): 3-6-35, p. 1 12-18-3 3, p, 4 sp2: 3-23-37, P. 3 235 tn: Ti-5c: I- 23-33, p. 13 3-6-35, P. b 3-6-35 , P* 10 3-4- 36, -d . 10 3-23-37, p p . l, 2 Tp: 3-6-36, p. 6 II— 2̂ — 3̂ P? p. 10 Tl-6a: 1-23- 3 3, p. 1^ 3-4-36, p. 16 3-6- 38, p. 6 3—6—3^, P. 15 Tl-6b: Tl-2a: 3-6-36, P. 6 3-6-33, p, 6 Tl-5c: Tl-2b: 3-6-36, p. 6 >-6-35, P. 3 3-4- 36, pp. 10, 11 Tl~7a: 3-6-38, PP. 6, 7 3-6- 3S, p. 6 Tl-2c(see l-10b): Tl-7b: 3-6- 32, pp. 6, 9, 10, 11 3-6-35, PP. 3, ^ Tl-3a: 3-4— 36, p. 10 3-6-33, p. 6 3-6- 35, p. 3 3-4-36, p. 10 Tl-7c: 3-6-38, pp. 6, 7 , 10 3-6-35, P. 3 Tl-3b: 3-4— 36, p, 10 3-6- 33, p. 6 3-6-35, p. 3 Tl-7d: Tl-3d: 3-6-35, P. 3 3-6-35, P. 3 3-^36, p. 10 3-4— 36, p. 10 3—6—33, p. 6 3-23-37, P. 5 3-6-38, p. 6 Tl-9a: Tl-5a: 3-6-35, PP. 3, ^ 3-4-36, p. 10 3-6-35, p. 3 3-23-37, P. 2 3-4-36, p. 10 3-6-33, p. 6 3-6-33, p. 6 Tl-9b: Tl-5b: 3-6- 35, pp. 3 , ^ 3-6-35, PP. 3, ^ 3-4- 36, p. 10 3-4— 36, p. 10 3-6- 33, p, 6 3-23-37, P. 1 3-6- 38, pp. 6, 10 236 3-6-35, P. 3 3—6— 35, P* 3 3 36 10 3-4— 36, p, 11 — , p. 3-23-37, P. 2 3-23-37, P. 6 3 6 33 3-6-33, p. 7- - , pp. 6, 9, 10 T2-5a: Tl-lOa: 3-6-33, p. 7 3-6- 35, pp. 3 , 4 3-4- 36, pp. 10, ll T2-5b: 3-6-38, p. 6 3-6-35, P. 4 Tl-10b(see l~2c): 3-4-36, p. 11 > 6- 3 3, p. 7 3-6- 35, p. 3 3-23-37, P. 2 T2-6b: 3-6-38, p. 9 3-4-36, p. 11 T2~3a: 3-6-33, p. 7 3—6—38, p • / T2-6c: T2-3P: 3-6-33, p. 7 3-4-36, p. 10 T2-6d: T2-3c: 3-6-35, P* 4 3-6-35, P. 3 T2-7a: 3—1*!— 36, pp. 10, 11 3-23-37, P. 5 3-6-35, P* 4 3-6-33, pp. 6, 7 3-4-36, p. 11 3-6-33, p. 7 T2-3d: T2-7b: 3-4-36, pp. 10, 11 3-6-3 3, p. 7 3-6-35, P* 4- 3-4— 36, p. ll T2-4a: 3-6-33, p. 7 3-4-36, p. 11 3-6-33, p. 7 T2-7c: T2—4b: 3-6-35, P. 4- 3-4-36, p. ll 3-6-35, P. 3 3-6-38, p. 7 3-4- 36, p. 11 3-23-37, P. 6 T2-9a: 3-6-3 3, pp. 6, 7 3-4-36, pp. 10, 11 T2-4 0: 3-6- 38, p. 7 T2-9b: 3-6-35, P. 3 3-4-36, p. 11 3-4-36, pp. 10, 11 3-6-33, p. 7 3-6- 38, p. 7 237 3-6-35, P* 3 3-6-35, p. 4 3~4— 3§, p, 10 3-4-36, p. 11 T3~5c : T4-5a: 3-6-35, P. 3 11- 24- 34-, pp. 6, 7 3—1|— 36, p. 10 T4- 5d: T3-6a: 3-6-35, PP- 3, 4- 3-6-35, P- ^ T4-6a: T3- 7a: 3-6-35, PP- 3, 4- 3-6- 35, p. 1; 3-4- 36, pp. 10, 16 T4-6b: T3-7P: 3-6-35, PP- 3, 4- 3-23-37, P- 6 3-6-35, PP. 3, 4- 3-4-36 , p. 10 T4— 6c: 3-23-37, P. 5 3-6-35, P- 3 T3-ga: T4-9a: 3-6-35, P. 4- 3- 4-36, p. 10 3-6-35, PP- 3, 4- 3-23-37, P. 6 3-6-36, p. 10 T3~Sb: T4- 9b : 3-6-35, P. 4- 3-4- 36, p. 10 3-23-37 3-23-37, P- 6 T3- 9a: T4-l0a: 3-6-35, P P - 3, 4- 3-6-35, P. 3 3-4- 36, p. 10 T4~l0b: T3~ 9b: . 3-6-35, PP. 3, 4- 3-6-35, P- 3 3-4-36, p. 11 T3-l0a: T5- 7a: 3-6-35, PP- 3, 4- 11- 24—34 , pp. 6, 7 3-4- 36, pp. 10, 11 T5- 7c: T 3-10I): 3-4- 36, p. 17 3-6-35, P- 4- 3-4— 36, pp. 10, 11 238 3-6-35, P. * I- 25-34, p . 5 3- ^ 36, p. 10 I I - 211- 311, p. 11 3-6-35, P* 3 T6-9b: 3-it— 36, p. 10 3-6-38, p. 15 > ^ - 35, p. ^ 3—U— 36, p. 10 Ts^: 18-Sib: 1-23-33, p . ill 11 I- 25-34 p - 53-1+— 36, p. I I - 214— 314-, p. 8 3-23-37, p. 6 3-6-35, p. l 3-23-37, p - 6 T g - l O a : 3-6- 38, p. 15 3-p~35, p. 4 Tsg: 3-11-36, p. 11 3-23-37, P. 6 TS - 10b: Tu: 3-6-35, P. *1 3-11-36, p. ll 1-23- 3 3, p p . 3 , 1 4 12-18-33, pp. 5 , 6 TS-lOc: I- 25-34 p. 5 II- 24— 3 4 , pp. 8, 10 3-6-35, p. ll 3-6-35, p p * l, 2, 3 3-11- 36, p. 11 3-23-37, p* I1! , 3-23-37, P. 6 3-6- 38, pp. 2, ll, 15 Tg-10d: 3-6- 35, p. ll 9—13— 3^, P* 3 vl : 1-23-33, P- ill 1-23-33, P. l4 1-25-34, p. ll 12-18-83, pp. 2, 6 3-6-35, P. 1 1-25— 34-, p. 8 3-6-38, p. ill 3-I1- 36, p. 3 tB2: v2 : 1-23- 33, p . 14 1-23-33, PP* 3, l4 I- 25-34, p. 4 12-18-33, p. 5 I I - 211- 311, pP. 3 , 5 I- 25-34, p. 6 3-6-35, p . 1 I I — 24— 3I4-, pp. 2, 6, 7 3-23- 3 7, p p . 1 ,2, 3 ,9 3-6- 35, p . 1 3-6-38, pp. 9, 10 3-ii-36, p. 7 3-6- 38, p. 15 tsij.: 239 1-23-33, P. i4 1- 23- 3 3, P. I k I- 25-3M-, p. 6 1-25-3 4, P. 2 II- 24-34, p. 4 3—iJ— 36, p. 7 vl6; vip: 3-23-37, p. 7 3-6-32, PP. 2, 15 1-23-33, PP- 3, i4 1-25-34, p. 4 V12: 3-6-35, PP. 1 , 4 >4-36, p p . 1 1, 1 5,,17 1-23-33, P. 15 3-6-32, PP. 6 , 7 , 14 v20: V 1-23-33, P. 15 1-23-33, p p . 3, i4 12-18-33, •p p . 2, 5 V21 (=V16) I- 25-3 4, p. 7 II- 24-34, pp. 7 , IS 3->36, p. ■1 7 3-6-35, P- 1 3-23-37, P. 7 3-4- 3 6, pp. q, 16 3-23-37, P. 4 val • 3—6— 3 2, p, 15 1-23-33, P. 15 v6: 1-25-34, P. 7 1-23-33, P. 14 vpx: 1-25-34, p. 6 1-23-33, P. 15 v7: vp2 : 1-23-33, P. 14 1-25-34, p. 6 I- 23-33, P. 15 II- 2>34, pp. 6, 7 vg: 3-6- 3 5, p. 10 1-23-33, p. l k VP3: V10: 1-25-34, p. 5 > 23- 3 7, p. 7 vpi+: 3— 6-33, p * 9 1-23-33, P. 15 v12 • 3-6-35, P. 13 1-23-33, P. i4 w 2: 1-25-34, p. 6 3-4- 3 6, p. 7 1- 23-3 3, p . 15 3-23-37, P. 10 3-0- 3 8, pp. 12, 13 vi^(=yg2): w2: 1-23-3 3, p. i k 1-23-33, P. 15 240 xnl : 11-24-3^, p. 10 1- 23- 33 , p . 15 >4-36 > p. 3 3—23—3 7 > p p « 6 , 1 5 y x (=y3 ): w5 • 3- 6- 35 , p p . 3 , 5 , i 4 3- 14—3 6 , p , 1 6 i - ? 3- 33 , p. 1 5 W6: 1- 23- 3 3 , PP- 3 , 1 6 1-23-33, P* 15 12- 18- 3 3 , p . 6 1- 25- 34 , p . 6 m ! 3- 6- 3 5 , pp. 4 , 5 , l i i 3- 4- 36 , p . 9 1- 2 3- 3 3 , p . 15 3- 23- 37 , PP. 2 , 15 1- 25- 34-, p* $ 3- 6- 3 8 , pp. 3 , 7 , 9 , 1 5 p I V SU-X3- 31+, P. 9 3- 4- 36 , p . 9 Wh: yd: 1- 23- 33 , P. 15 1- 23- 33 , P . 16 1- 25- 3* , P. 7 1 2 - 1 &-3 3 , p. 4- wl: yf: 1- 23- 33 , P. 15 12- 18- 33 , p . 6 I- 25- 3* , P. 5 9- 13- 34 , p . 9 I I — 2 —̂3* , p. 6 3- 6- 35 , P* 1 y g ? : 3- 6- 3 3 , p. 1 5 3- 6- 3 5 , P . l 4 ms3: - — , p . y g a ;11 24 34 2 3- 6- 35 , P* 2 9- 13- 34-, P . 3 3- 23- 37 , PP. 7 , 8 3- 6- 38 , pp. 8 , 9 ygi: wx: I- 23- 3 3 , p . 1 6 II- 24—3 4 , pp. 67, 1- 23- 3 3 , PP- 3 , 15 3- 6- 3 5 , p . 1 1 12- 18- 33 , pp. 2 , 6 3- 4- 3 6 , p. 3 1-25-34, p. 8 9- 13- 3 4 , p . 8 yg2<=vi4): 3- 6- 35 , PP. 4 , 12,13 , 14 3- 4- 3 6 , pp. 3 , 10, ll , 1- 23- 33 , pp. 3 , 1 6 3- 23- 3 7 , PP- 7 , 10, 11,14 12- 18- 3 3 , p . 2 3- 6- 3 8 , p . 1 6 1-25-34, p. 8 3- 6- 3 5 , p . 14 3- 6- 3 8 , p. 1 6 241 ygy ia-10-33, P* 5 11-2*4-3*4-, D . 1 9-3.3-34, p. 9 ysi : zg-j'- 1-23-331 p p * 3, 16 12-10-33, P* 3 3-6-35, P. 3 I- 25-34, p. 6 II- 2*4-34, PP* 2, 6, 7 zl: 3-11- 36, p. 7 I- 23-33,, P. 16 ys2: II- 24-34, p. 3 1-23- 33, p* 16 yt: 1-23-33, p. 16 3-6-30, p. 13 zbij.: >-6-30, p. l zb,..: 5 11-2*4-3*+, p . 1 3-6—30, p. 16 zb6: 3—6—3 0 , P « 2 z (=zg1): l-2>-33, P. 16 3-6-35, pp. 3, 12 zg1(=zg2 ): 1-23-33, P. 16 3-6-35, pp. 3, 12? 242 4 0 <&/. 7ATL 0 60 Wjtmrfr X A t *,, *t? * fV II 1 '\« *fo i 10 72 20 7$ 02 *4 05 04 A r 2 A\ <54 2 ' “ 'I ^7 4 d t >*<. J * ^ 5 ck 16 Cb /OOTV. ‘ v* 4 ' ^ 6 SI /W, |00 105 ?4 X 103 >2 y 2 W/t III •yt- A IH x» S /TTU/̂ /”uz /Muj u / t * rnz ir* vjf ^ 0 t̂ l( if- ^5 /frrr\,_ X cnJut^- rr̂ âu cA^ Xt̂ru <̂ X̂ 7rẑ -x̂ «r̂ & f f /l#fisrrukf^ Ĵ &xû j r j s yrui^rot ,̂ . £ k ^ V t X t - n ^ y^ruiu^. 'iT iS ^ 3 ~ /6r a^ U M ^ J L ty^uX M-cy, yrL - ^ ^ ) . 243 8 9 4K w a * dt*.3 o 'fKr ■isru 0 AT1.0 O W r0 AT, 2 "m IZ >v- 13 14 srM '* I0 siA'l 22 2t cf a 24 20 /1\A>, 28 t * x t i 24 7d uId 30 31 r * 32 3 5 Ha*, 3̂ ŷ O~ynjê -X~ /̂ rlJU*£Ls s4XifafaLA/~yrt*4̂ filjL JjKAs 'tfj' X^Ufa^ ^trU4A ALfaMYU X X XxX̂ faî yyî n̂ k̂ /{Af̂ Xis /X̂JXyHfafy\̂k*̂faX sCJlfa\X*t 244 MAIZE GENETICS COOPERATION NEWS LETTER 13 April 15, 1939 The data presented here are not to be used in publications without the consent of the authors. Department of Flant Breeding Cornell University Ithaca, N. Y. 245 M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A , N E W Y O R K January 21, 1939 To Maize Geneticists :- The call for material for the 1939 Co-op News Letter has purposely been delayed to allow you more time to analyze last summer’s results. Since it is desirable to have the Letter available not later than the first part of March, however, the individual contributions must be received by the Co-op by February 15, 1939. In order to insure a more uniform system of presentation, please refer to previous News Letters for suggestions concerning the form of your write-up. Sincerely yours, X). j o . D. G. Langham, DGL: B Secretary 246 I Jot. / 3 M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A , N E W Y O R K April 15; 1959 To Maize Geneticists: The material in this letter was obtained fr a on md mha as n yb e se on u rco er sg anized under the following heads: I, General News Items. II. Seed Stocks Grown in I 1I 9I 3. & *S eed St ^ocks Received For Propagation ±n ijj I jV. * Maize Publications. V. Maize Genetics Cooperation Mailing List. I• General News Items iT-n-i vp.Tsity of Buenos Aires^^uenos_Jares ; Argen - t- i- n- a! The Argentine varieties of commer a cn id a lc a cn o rb ne ac rl ea s as li lf i He id n tin three groups according to endosperm. color. ^ Varieties with orange endosperm. X), » 1 yellow " c* » n white fVne "tical analysis shows that both gro g- ue pn se s aŶ aŶ n dY- v bY -, c. a rrI yn tt hh ee first group the varieties r _m ,or le on rt adon were tested: in the second group t C heo mu vn a ra in ed t iA em sa r Ai ml al ro i lE ln oa ns. The a dia :n f:d U eb r ei ns c e du ie n t co o lm oo rd i bf ey ti wn «g « f actors. Long v a Wr hi ie tt ey Fo lf i nw th it te h ee n od no s yp erm tested, has the genotype 2iXi±jIy 2. The gene al, besides the k m np on wt n o ef f fc eh cl to sr o up ph oy nl l ther e dd eu vc ee ls o pt -h e int c eo nl so ir t° yf oI fn -ea 8 ther e ns de og sr pe eg ra mt ing A1A1. A w lh ai ic , h" ah na dv e a lt ah le , l ma os st t c ko em rb ni en la st ion may h a bv ee ra e cl oi gg nh it ze er d y be el cl ao uw s ec o tl ho er y. Plants ala y le l gl io vw e e en ad ro ss p we ir tm h. liI gn h tn umerous Fg, no plants of homozygous al and deep yellow or orange endosperm have been found. University of Minnesota, bt. Paul, 1..im p TTTinkage relations of gl^ with wx and sh. The sample of gli was found in Minnesota in one of our cultures and was being studied at the time of Dr. Sprague's report on gl^. 247 Recomb . Genes Phase XY xy. xY ££ Total Nor~ Sh Wx C3 213 66 39 172 4-90 105 2 1.k Sh Gl|| CB 20 2 77 55 156 490 132 26.9 wx Gl̂ . CB 235 17 22 216 4-90 39 S.O Order of genes sh-wx-glty. 2. Linkage of zebra seedling-1! (zb^) with ? in cnromosom a er e 1 Results similar to those obtained with F2 data. Recornb. Genes Phase XY Xy xY xy Total No. A Zbi| P CB 67 6 3 67 1^3 5 6.3 3 . An upright habit ot ttahses el characteristic of inbred line 19 used in 1st cross K (15 x 19) proved recessive in cross w ei st h normal tassel but dominant in the of the cross between upright and ts^. H. K. Hayes k I believe it is possible now t tr or ou aD rS r' ai nn g eo ur t hel i ln ik na kg ae g em ap still gr fo uu rp ts h era ,r e so o ri te hn at t ed t hei n la i nks at gil el mor t en ut nh ip f oc rh mr o sm co hs eo mm ee s. i n rI en l at th ie o nl in n ko ar gn e* l me at pt e sr e™ n0 tt he oy u t ar we i tno ri t.e in e te ld ^ ts o t ? ho a t o ti hei s upi pA e rt h ee ndd i cr oe rc rt ei so pn o no df s the short arm end of the w ci ht rh o mt oh se o me except in id oi nc a ot fe s * 3t h aa nt d t ph ri os b ag br lo yu p # S.s hould ®b ^e °r "ev Ce at th■nni rn st e do -^zerc r w ii tn h t ^he ad ti r te nc et i zo en r o 5 o f the h sn hor t t nr ac r m v t- ep o nds .e ri * ve r̂ n be ,lo b wu .^ th Te hi e l nuw me bes rt s t ah ra et tf oh ol s s mg ar llo ,u p shou i l d a bt e t rh ee v ez rf sl eo d p ao li sn ot . plT ah ci is n gm eans tha t th l tl he ze ra oa pn oe iw n tL t -.a il lc o bm ee along, but that will be tru o et he or f g sr eo vu ep rs a l as they stand now. c The series of r and R alleles s lu im sm ta er dv id no e ts h en o ct o ri nn c ll iu nd ke a gt eh e"one desig " nated o in n P tl ha en t o rc io gl io nr as l (pp. th 1e 1r 1e - 1d 1e 3s ) cr ai s be Id ** .a s giving a lli en le wad silu p t- erc c tn y pa en st he (Ar s o w Pi It h a r ae d col Por at th te h e o br ad si en ar oy f r t& h’ e al pl le al nte s ,g av we n erg er ae se On ne as nu tg hg ee rs st i ao nn d i gs ret eh na t bat sh ee ps lu ap ne tr ss .c ript for S tV hee rT -sS eK rie esU me ay. ne» e, d < , » « „ color, ,111 color, 248 ffeSt j r - j r g i n i a U n i v e r s i t y , yjQT j ^ i o s u J L J — I S■ ^" i . “ L in k a g e d a t a o n c h ro m o s o m e S : R e c o m b . Genes Phase XY S x xY XI T o t a l N o . JL Msg J i CB 35 1 3 ill SO k 5.0 ^sgTS~9a CB 51+ 26 16 2b 120 i+2 35.0 J 1 T S -9 a CB 56 IS 26 31 131 33.6 order: TS- 9a ~ ^1 - m sg - end of l o n g a rm • C , R . B u rn h a m p Sterilizing seeds for germination. A hyp s oo clu ht li oo rn i ts eold under the trade name uC t hh la on r ot xh Me ib sl e ea ac sh ii en rg tp oo w ud se er solution. s ol Fu it ei lon ds coa rf 5 n ^ s oa ak kd ed st ir no n ^g /2 ne lr o rof xo r l hour completely co t nh te r om lo ll ed ds but reduced germination. The a rn ed wn ao sr m va el r yg e lr im ti tn la et i mo on l da t and also at 2 . ri Fa ol r a g es no el tu it ci o mn a to ef - 2 co. of commercial Ohlorox t w oa t 1e 0r 0 i cs c .r e oc fo mmended, soaking the grai h ny sp o fc oh rl or 1i /2te hos uo rl .u tio °n ^s ® rar ^e on the market but may vary in the o f /t h e a c t i v e i n g r e d i e n t . ^ ^ R ig n e y a n d c . R . B u rn h a m dnrmeeticut Agricultural_,ExEeriment_Statlon, , ^ w Haven, Cpnn^ - -----1, 'in seeds treated with X-rays shortly af n tu em re ro fu es r tip la ii zr ae td i om nosaic areas are found associated a wl il t no f lot sh se ese _a ,s fi ly Identified marker gen T en s m s° un cv h c aa ss e Cs , a lr £e >a s sho 2w Hi *ng losses of any of these markers are liter the cell metabolism and indirect l“ ly th ae f fs ea cm te aw la ey u ro ot nh ee r c oa lc ot r.i vities of the cell are al i tn e rs et da ,r c nh o tf ao br lm ya tion, viability, and growth control. ^ ^ Joneg 2. Fine mottling of rrR seeds. In 1537 a c nu t ea7 r2 0 ofy S Cu o nnA ecC tir -when pollinated by C697 (a C R) g t avh ea t' sw ee er de s all mottled. There w k ee rrn ee l 6 9s -1 reS g ulw ai rt h very fine mottling, color f oew f tp ea nt c lh ie ms i teo df f tr o om c. one to a few cells each, ( Th ae ns de op r co ob la ob rl iy e sw se .r e fine mottling where no color o wr a sw e vr ie s ic bo ln et ,a minations. They are being tested;. In 193S seeds of the two classes were pl ro aw ns t ea dn d i n se sl ef pe ad r ator e again crossed by 697 A-tester. Two ears 1 249 K. ,hp fine mottled stock selfed produced onl f yi 'n we h im to et st ,l in sg o. l id,O ne a nde ar crossed by 69 in ( i go ar ve an 1d 8 0S 2 w hif ti en ,e m >o 2t t el oe ld x dk ernels. Thre m eo t et al re sd fs rt oo mc k tw heh en c oac rr so es sed by 697 gave 53 1 ^32 wc ho ia tr es ,e 2m 5o 0t t sl oi ln ig d a cn od l o9 r^ , fine mottled k p e*r re na et lsd .e via Tt hi io sn if sr o nm a k o : a 2 : 1 : 1 ratio m o et xt pl ee cd t ef da ct ifo r ths eh ow fs i nei ndependent inheritance with Mt. Does anyone have any convincing evidence a tl hl ae tl e of ist he n oR t r a n gene? Kempton's (GE r Na En T Ih Ce S i 4n :t e 2r 6p 1r -e 2t 7e *d 0 o dn a ^a an al . lelic "b r asis a0 s weH le l s ae sc u ar se sd u m2 in9 g . 12m ,o 5t ft ° led seeds wh n ef n t sh ee l fc eo dl ,o r we hd e rs ee ae sd s 3 3s h Vou 3l 7°d have been mot s tt la et de .s h He e e ix np ce oc rt re ed 25$ ctly whereas 33 l/3% o wf a st h te h ec o cl oo rr re ed c tk e pr rn oe pl os r. t ioS ne lfed ears are f o rr atd he et re rm ui nn sa at ti io sn f ao cf t ot rh yi s point. We plan to test thi c sr o bs ys i bn ag c ki f it has not been done. 3. White seedling olassification. cl Wa hs is ti ef i se ed e ds la it ni gs sf a cc at no r oi el y soon after th t eh e sy e ea dr se hg ae vr em i gn ea rt me id n ai tn e dt h ie f light. We use a fo nr oa l dg e gr lm ai sn sa t io nr c ua bn ad t ok re ep the temperat s ut re er i al bi oz ue td 7f 5o °r r •1 m si en eu dt se ai rn e a 1* solution of Hg c Ce lt gri and dis h pe us t, in1 00 to a dish. Under the d se ev e cl oo np ds i tr ia op ni sd l cy h la on rd o pc hl ya ls ls ification can usually be compl w ei tt eh di n a week after planting. if. Seedling classification for re g de r om ri n ga rt ee ed n b by a st eh .e a Sb eo ev de l im ne gt sh od can be classified acc t uh re a tg er le ye n f ob ra se (rE or RE ), or t rhe e d f bi ars st e t (r ru r e orl e Baf )h > as Tb he °e n found the cl ma os ss ti f ri ec la it ai bo ln e. plI af c ea n fy o ra ntho-oyanin color a p ip se a pr r ea st e nt th e i tt i wp is l lo f the leaves. c Sl ea es ds li if ni ge sd sc oa n g es rt mi il nl a tb ee d p al na an ted without in m je ut rh yo d o ro f sec tl ba as cs ki .f ic (a Tt hii so n is not new. a In td ih si s u ss et du d be yn t Ds r .a t ^ tt ah de i eU rn iversity of Missouri. a s Ii tt m isa y cb ie t eh de l hep rf eu l to some unfamiliar with it), R. Seeds germinated in the germinator s i pl rk os d ue ca er l py o. lleL na s at n ds pring one lot of C50 was a p sl wa en et te d c oi rn n t ih ne b ref di ,e ld on June 1. s toc Ak n ow ta hs e rp u lt o ti n Ot xo tt hh ee sg ae mr em inator. As soon w e al sl ts ht ea r st ee ed d lt ih ne gy s w we er re e put into four i g nr ce he n ph oo tu ss e a nf ao r k ea pb to u it n t *w o weeks before tr Th ae n sp pl la an nt ts i ns go tot re ta ht e ed pro a.d uced pollen p l aa n wt ee ed k i an het ah de of fi e tl hd o sa en d there was a dif t fhe e res ni cl ek in og f d na it ne es . d aysT hi ms method may be ut e ia lrl iy z et da s fs oe rl s s ea cn ud r is ni gl ks of stocks, without planting early. 6. spn and lo not allelic. We now have definite proo s fp -̂ t ha an td lo on chromosome 4- are not alleles of the same gene. In 250 fact they are located on opposite sides of sur Complete evidence will be published shortly. w< R- singlet0n 7. A hybrid between a Lancaster inbred (696-3c • )in a19 n* d56 Parnunkp er yo duced all semi-sterile ears. Cytological n f e xt ah me inh ay tb ir oi nd in 1938 showed the presence of a hetero l zo yc gat oi uo sn ti rn av no sl -ving chromosomes 1 and 2. The point of i in n tc eh rr co hm ao ns go em e 1 is in the short arm, at approximately 6/ d 1i 0s ta ofn ce t hef rom the spindle fiber attachment region to th te h ec h er no dm o os fo me. The break was between the spindle le fn io bb eron at nh ae a short arm. The point of interchange on chr o on m ot sh oe m el o 2n ,g arm, is approximately half way between th f ei be sr p ia nn ad l e the end of the chromosome. Chromosome 2 als k on o hb. a s aS eed of the homozygous translocation is available. g. A subterminal knob was found on the long arm of chromo- some 9 in 3g-117i (segregating spp and io), This knolD is 81ffill i an r appearance to the chromosome ^ knob, but ex c ar mo is ns ae ts i ow ni t oh f unrelated stocks showed no evidence of a tra t ni so ln o ci an -volving chromosomes 9 and k. The knob is quite t h ce loe sn ed to of the chromosome with about l/5 of the long arm beyond it. Seed of this is available. University _of_North Carolina, Raleigh, N. C_. - ” 1, Opaque endosperm-H. Endosperm similar to Op and o. Classification good in white dent stocks. Seed s n eo gr rm ea gl a te( %)> 25> opaque (oy). All Op seeds produce normal plants while all Op seeds produce dwarfish, yellow-green striped, abnor- mal leaved plants which die in four weeks under fiel S do m ce o ns de ie td il oi nn sg .s of qH lived two months in greenhouse but never got over 5 inches tall. Germination of J oH see d approximately Paul H. Karvey 2. Red leaf tipCrl). Appears when plants are 8 to h 1i 2g h iu nn chd ee sr field conditions. Red color graduall ti yp et xo t ec no dv se r f ra op mp roximately one-half of blade. Classification good in Fp. Segregates 75> normal (HI) t0 25a’ red (rl). ^11 p rl lants smaller than normal. 3. Burned leaf (bu). Tissue in leaf tips begins to die t au nr dn brown when plants are 10-18 inches high und t eio rn s f. i elCondition spreads to one-half or more of r le es ae fm ,b les s omc eo wn hd ai tt ions caused by certain plant fooa defi C cl ia es ns ci if ei sc .a tion fair, though a few heterozygous plants e sv hi od we nc soe m eo f burning along leaf margins. Segregates 75/* ( nB ou r) mat lo 25$ burned (bu). All v bu plants smaller t— ha n normal. G. K. Middleton 251 Texas Agri cultural Experiment Sta^QnA__C_ollege Station,.Texas l With further reference to our hypothesis that (l) m n ar ii zr e-i nated from a wild form of pod-corn, (2) t P hro atd u tct e osinteo f i sn a tt hu er al hybridization between m 7 aize and Tri? psa) ct uh ma ,t am no ds t North American varieties of maize^ are con w ti at mh i nT ar ti ep ds acum, we have spent a good share of the re pv ai se tw i yn eg a rt h me archaeological and historical evidence whi L ca hr i hn ag s o an this problem. We have found nothing seri f ol ui sc lt y w ii nt h cot nh -e hypothesis and a great deal of evidence in support of it. In the last News Letter we made the suggestion th k an to b ts h eo n the chromosomes of maize may have come orig T ir ni an ls la yc um f, r omi n which case pure South American varieties f o mu in gd h ti n bew hich the chromosomes were knobless. This h bo a s th pe r oc va es de . t o Of 17 lots received from Peru, all bu l te ss t woc hr ho am do s ko nm oe bs -. Collections from other parts of Sou h to nw ev Ae mr e, r ica al ,l had knobbed chromosomes, the average numbers being as follows i Venezuela....5*50 Dutch Guiana.....3*00 Uruguay...... 5 .00 Argentina........2*00 Brazil....... 4,03 Peru..... ....... 0.33 Paraguay.....3*50 If the knobs on maize chromosomes have come ori T gr ii nn as la lc yu m f roi mt is evident that Tripsacum-infected var r ie ep tl ia ec se d h ap vu er e maize varieties in all parts of North A m ae nr di c Sa o ue tx hc ept the Andean region, which we regard as c e tn ht ee r p ro if m ad ro ym estication. Bolivian varieties have not s tu yd ei te d b ef er no m the standpoint of chromosome knobs, but we a p na tt ie c it -hat the majority of them will be found to be knobless. The objection most frequently raised to the hypothesis that m aize originated from pod-corn is that pod-corn is s t th ee r ih lo em o iz ny gous condition and a sterile form could s s ce ar rv ce ed l yas baa v ep rogenitor. We have attributed pod-corn to s t sh te e rf ia lc it t y that it has been maintained in a hetero t zi yo gn o uf so r conb do im any generations it is now a monstrosit z yy g wou hs e. n hoWe m oh -ave suspected, however, that a fertile, f o hr om m om zi yg gh ot u ss till be developed by selection since there v a ir si a gt ri eo an t in the expression of the glumes and oth t ei rc s cho af rap co td e- rc io sr n. During the past season we have found t T hS ar t g te hn ee apparently is a strong modifier oi fertility Oj. ju±i_ plants. Homozygous tunicate plants carrying the Ts^ gene are highly fertile on the pistillate side and exsert a an t fhe er ws . g oodS elf-pollination is impossible because th d er i se id l ku sp b ae ref ore anthesis occurs. Sib-pollinations c h ao nw e bv ee r m, a dea ,n d we expect to have true-breeding stocks of pod-corn available in the near future. P. G. Mangelsdorf and R. G. Reeves 252 nuke University, Durham, N. C*. - 1 , Lg“ (dominant liguless ) is in chromosome 3 as shown by the fooilll owing summary of data from six small cultures: Genes XY ll xY Total Rg Lg^ RB 3 133 12^ 0 265 (p = .0 11) A greater portion of the ligule is present in Lgj plants than in either lga or lgp plants. But for the characteristic tii i puless" appearance of the plant as a whole the character might more appropriately be called "defective ligule". Classification (except for seedlings), viability, and fertility (except perhaps for homozygotes) are satisfactory. A test for allelism with lgp and three-point tests are being made. H. S. Perry 1. List Of translocations involving Near left end (i. e. short arm)- T3~6b S .3 d^ ± 0.5 T3-7b s .3 + 0.4 T2-3c s .2 dx ± 0.3 Tl-3d d]_ + 0.6 ddle region - T3-9a tSJ| - 2.9 - dj- 3^.0 - T - 25.0 - !g2 T3-7a ts^ - 5*0 - d,- 20.2 -T - 15.9 - lg2 T3-3b L .1 ts^ - 0 - dj- 17.6 -T - 1^.3 - lg2 T3-9c L .1 T3-10a L .1+ ts^ - 10.^ - d - 11.2 - T - 1 1 . 7 - lg2 T2-3b ts 4 - 1.1 T3-10b ts^ - 0.3 T3-10C tsl| - 0.7 T3-6a d-,- lS.O -T - 12.0 - !g2 T3-5a 2^.5 -T - 7*9 - lg 2 253 g. Tl“3a L .2 2 - dr 23.^ - T - 5-9 - ig2 T3-^a L .6 tBJj. - dp- 29.5 "T - 5-7 — 7^2 Near right end - T3-7c l .6 tŝ . - 20.0 - T - 22.0 - a T3-9h lg2 - 7.9 - T - lg.O - a T3-5h na - Ij-.g - T - 19.1 - a T2-3e na - 7.5 - T - 20.7 - a T3-5c na - 11.7 - T - 12.5 - a T2-3d na - 13.0 - T - 7.1 - a List of translocations involving chromosome 6 - T>-6b Satellite Clarke and Anderson, 1935 Tl-6b Satellite Burnham, 1932 T2-6 Satellite Clokey (unpublished) T5~ 6b Satellite McClintock (unpublished) T6~9a Nucleolus McClintock, 193^> Anderson, 193^ T6-10b s .5 McClintock (unpublished) TS-6c s .1 McClintock (unpublished) T2-6a s .1 Burnham, 1932 T4~6a L .2 Very near Y T4~6b L .2 Very near Y T1-6c L .2+ Very near Y T6-9b Very near Y tU-6c L .2 Probably near Y (not well tested) T2-6c L .25 Probably near Y (not well tested; T2-6d L A Near PI and sm. Probably T-Pl-sm T2-6e L A Near PI and sm. Probably T-Pl-sm T6-&a L .5 Near PI T2-6b L .6+ Near PI T3-6a L • 6+ Near PI (Probably T-Pl-sm/ Tl-6a Brink and Cooper y-Pl-S-T T6-10a L .7 Pl-sm-22-T E. G. Anderson Cornell University,_Ithaca, N._Yĵ 1. The Linkage Summary suggests a possibl a en d alY£ ln e. i ismT he ofy are distinct genes, as an Fp between them c e od n to an il ny - green plants. In F2 both and yg2 segregated. 2, Dull endosperm, du, which intensifies suam and sup ( C so er en Letter of March 23, 1937, p. 13) e f hf ae sc t n oo n d ist? i-. n ctT lh yr jb vu ee i ss ie bp la er ate crosses of du x su F 2p S w es re el f me ad d. e “ aS ni dx ears from each F^ showed no definite effect of 254 LO. OJ i +C3Q du on su2. Any such effect is very slight if existent at all. Therefore, the mechanisms by which the sup anc ̂-^2 Senes ac't mus'k be different, at least in part. 3. Slit blade, sb: has shown various abnormalities. Some- times Fp ratios are atypical in crosses involving sb. Last year an g:i ratio of sb was reported. This year one plant of 90 FpS was a dwarf, resembling migh. Various genes have appeared follow- jncr sb crosses (see below) 5 some of these, at least, seem to be n ew. In the progeny of an open pollinated mishsb plant there was one very abnormal plant, It was ms, striped, bm, with a silkless ear, possessing much enlarged glumes. Slit blade itself is vari- able, ranging from almost normal-appearing plants 1 to small deficiency-like” plants with narrow, thick leaves. Many sb plants are nearly or completely sterile. In the light of these divers abnormalities, it is suggested that sb is, or is closely accompanied by, some chromosomal abnormality. Possible new genes from sb crosses: tw k — an adherent showing in both the seedling (causing it to be°twisted) and the tassel. Viability good. Classification ^°°mi — a semi-dwarf with compact tassel, rather stiff leaves, smallbseeds. Viability good. Fertility good. Classification good except with lg, g — a vigorous golden, showing golden late. May be g^, ior it showed about 30$ recombination with a. John Shafer 5 . F0 data (News Letter, March 23, 1937) indicated that pbh. is located between Y-i and PI in chromosome o. Backcross dat o ab tained last summer; however, suggest rather close linkage of Yp and pbx. Backcross data: Penes Phase n xy xY Total A Recombination CB 137 2 139 32S 0.6 Three-point test: F-j genotype 0 1 2 U 2 Total Y1 + PI 170 132 - 2 ^7 35 1 1 3SS + pbx + 302 2 S2 2 0.5$ 21.1$ 0 .5 4 255 Whether pbx is located to the rightor to the left of c and ec novp i td ed from these data. The wh \ i te ano d bt ya ei ln le od w f pr ao tm c hb ea sc k oc nr osses are co Pt nh so i” de e rf ao bu ln yd l2 an r gp ei re b ta hl ad n plants from the F2 , and. are found not o T nt lyh e leaves but also on the husks. This is attributed e tf of ec tt h e of modifiers rather than to environment.^ ^ Lebedeff 6 Sterility in tetraploid maiz ][_ e0 . An i ib nve sc ta iu gs ae ts i oo nf ot fh e t hv ea riation in degree ? o f d si tf ef re ir le in tt y l oi on se es r vo ef d tetraploid i mav it zo el o wg af sc a mf a de bg oe tn he t fi rc oa ml ta hn eg les. In a study h on ft h m is cel rf o— ss pt oo rr ol gi ee n ea sn id s , self-fertile lines s 1 h0 o) w eo df aq u la ad rr gi ev a nl ue mn bt es r at diakinesis. riv Ta hl ise nt inf do ir cm aa tt ei so n t hi as t not an important factor in causing sterility in tetraploid maize. The chromosome number of the microspo p rk o s vM au rc ih e do f f rt oh mi s va tr oiation was found to u n bi ev a dlents a un ed tn oo n t- hd ei s lj au gn gc ti go n of chromosomes re f sn urf lf tli it ni go n i ^of t hmi ec ^r onuclei, and to o an e les se sp ea rr a et xi to en n to f toq u ta d er ivalents. Fro n mS u oa nl el v t oi n s iu xn i cv ha rl oe mn ot s o. mr eo su ,p s, were seen f to li aH go -i in nr r s porf ol ca ym tet ee ss sh ha ov wi -n g Itf to 22 chromos ? o■{ mm eo st i ao rn ea l c ons si in dc ee r edthe chromosome a ° nt ue mt br ea rp sl o oi fd °ma = tH ho ei ) z pe rB op gl ea nn yt o( fS n has be , e7 n to s hoh w2 n , tT o he r af nr ge eq u fe rn oc my of microspores h h a-r vn im nn gs o bm ee ts w ea eg nr e 1e 8d o.v ne dr y 2 2 weIlfl tIwith the percentagef ood pon oe f n a pparently e ferhle and sterile lines in which this was s tudied. Four F, populations resulting from crosse w si t bh e ta w eh ei ng h l1 id ne eg sr ee of pollen abortion ( d 2e 5g $)r ee a no df lp io nl el s en w ia tb no r at i 1o n ̂(10$), showed a a bo lr owt ed « ep ao nl l pe en r, c es nu tg ag ge es t oi f ng a possible genic basis for tais. The coefficient of correlation between degree o a fb o pr ot li lo en n and percentage of aborted ovule b sn ,p s w ow ee nr e o nc lo yn sidered, tlwas found to t h ba et -f Oa .c 6t 5o 1r s ± causing pollen abortion are also opera ve n ing ovular abortion. Evidence was obtained indicating that geneti l ci t fv a cw te or re s a fl os ro involved in causing h so tl ed r im la ii tz ye . m S to em xe . as elf-compatible lines i nc wo erm ep at fi ob ul ne d w ti ot h b e ot ch re or ss self-compatible line - snn r we nn et. n usT eh dis asr el tha et ionship was true o f e vd ei nf f we nr ee nn t t hp eo l el fe fn e cw as compa o rn ee d e oa nr twb oe i en arg s se fl rf om- po tl hel in sa amt ee d p an ad n t ,he othe c rr o cs rs oe ss s -b pe ot lw le ie nn a ts ee dl .f -c Io nm patible and self-incompati u bn li em od sa tl o ckd si st c ribution was obtained for the Fx and a bimodal 256 distribution for the Fp population, indicating the existenc a et ol fe ast one dominant or epistatic gene for self-co mq patia tudv b io lf i tr ye .c iprocal crosses between sel i fn -c co om mp pa at ti ib bl le e l ai nn de s ses howed that self-incompatible line n s0 m wn ea rt ei b cl re o so sn -l y when used as the pollen parent, n ol hl oe n evt iu dbe e ncc eo mp ofe tition wa3 found in a compatib a self- le crosc so m bp ea tt wi eb el ne and a self-incompatible line when mixed pollm ations were made to determine this. Some evidence was obtained indicating that n u tm hb ee r c ho rf o mt oh se o mp el ant was not very important with respe o cf t f te or t di el gi rt ey e since a 38! chromosome plant was t i fl oe u^ ns de e tod bs ee t) 7 5*w h fe en self pollinated. This suppor 6 ti s0 _n t ht eh a ot o nm ou lc uh - of the sterility in tetraploid maize is g de un ei c tor ather than chromosome number difference. If genes for self and cross-incompatibility are c ca ou nsi cn eg r: n es dt e ir ni lity in tetraploid maize, it is necessary t t oh a at s st uh me es e genes were present but inhi c ba im te e de f if ne ctive because of ® a genic unbalance res o us lo tm ie n gd o fu rb ol mi n cg a, ri s. e. upon doubling some genes inc t ri ev ae sn ee ss i n an efd f eo ct hers remain static as far as their activity i concerned. Harold E. Fischer 7. A sib cross between two iojap plants in a cul f tr uo rm e A o. btA a. inB er dy an gave an ear which is homozygou l si n fg os r. whF io tr et y s es ee de ds from this ear were planted. p- Te hr im ri tn yat -e ed i; g ha tl l the seedlings were wnite an w de ek ds i. e d wT ih ti ns ini s twi on terpreted as a case of extreme variation in the expression of iojap. g. In a tester stock of 11 plants with the genetic t ci oo nn s tp ir t u-v? A b pi C R eight plants were dilute sun red, as ex pected, but three showed occasional red sectors h iu ns k ts r,, e a ln ed av et sa ,s sel. When the leaves were st s rt ia pl pk ede x dp oo ws ne d a nt do tt hh ee sunlight, red sectors appeared on it, to A op .p arently b is unstaole and mutates to B. 9. Linkage of gu ahd thin kernels. In a cross of Inored x II « , three FP cars segregated 25# thin kernels and the other f our F0 ears were normal. Seed was taken from an ear segregating thin kernels, and the normal kerne t lh si n plon ae ns t. e d Theoreticall fy i, n ^aohshould have segregated 3.1 p -r io nu p e. a c^A ll 1*1 plants obtained from the ker f ne es ls s ;e oir e nog rr me ae ln ! tw mh ei -l e the 10 plants from the t g. h i. n kT eh ri ns e lb se h wa ev ri eo r suggests that the gene (or small deficie j ■) for thin kernels is closely linked with g^. 257 10. New characters in maize, teosinte, and maize-teosint h ey brids: Maize - adL - adherent plant. Can be classified in ea s rta lg ye ; s e' et di lp is ngo f leaves stick together. a Pl lm ao ns tt bn eo cr om ma el s until anthesis, when an b tr ha en rc sh ,e s t, a sa sn ed l silks become sticky and te V ni da b ti ol i at dy h ea rn ed . fertility good. Chrom. unknown. Te°Several plants each of Nobogame, Huix D tu ar ,a n Ng oo v ot ce ao ys ai nn ,t e a nw de re selfed and pr g oe gn ee nt yi c t ec sh ta sr a mc at de er s l. o r The following characters segregated in 3:1 ratios: zb^ — zebra seedling. ad£ — adherent leaves. d.j. — dwarf. pg_k — pale green (two cultures). ft — fine 3tripe. glt — glossy. — white seedling (two cultures). Cot — corrugated leaf (three cultures), gŝ . -- green stripe (three cultures]. ys+ — yellow stripe. la^ — lazy teosinte (reported in 193$ News Letter]. These genes will be crossed with similar maize genes to fo tr e stp ossible allelism. Malfd"--°reSonseb tod8hort day. Recessive to "we t ao k "l e rn eg st ph o no sf e day in maize. sin Mg el ne d elian charf ace tm epd - a r l .e ^ spikelets. Recessive to p s ap ii rk ee dle t fs e mao lf e maize. Segregates in 3^1 ratio. ^oi lins and Kempton, 192 tr — t 3 w )o *- ranke , d ear ̂ and two-ran ~ked cent t ra as ls e jl r. a ncR he c oe fs sive to the raany-ranked r a en ak re d a nc he n mt ar na yl - branch of the maize tassel. Mendelian o © r • pd is linked with tr with 2 0 recombination. Chromosome unknown. 11. Brittle stalk-X (bk ) reported by N e Rw .s GL .e t Wt ie gr g, a nM sa r ic nh t6 h, e 193*$, P- 12, is an allele of bk£ . Fine stripe-X (fx ) from the same report is an allele of li' D , C. Langham 258 II* Seed Stocks Grown, 193& 1, Testers. Chromosome 1^ ^ x p ẑ ) x ^ br fx zb^ Chromosome 2 : +/^5 (igl gs2 b x Inbred l)self (ws ̂ l g1 X gig) X (ws3 l g1 X g l 2) Igl e12 v)+ x fll l 6l t s x + / g l2 +/v^ x l g x g l2 V t S ! +/vi! Igl +/Bkl x 1Sl skl + /ba^ x b9.r> Chromosome J>: (pm x lg2 dx) x (pm x lg2 dx ) +/d^ x d^ +/ba^ x ba^ lgp d1 +/ tsty. al ^^2 ra2 (ts^? Rg x d^) x lg3/? Chromosome U-s su^ gl^ +/wl sp^ su^ Chromosome 5: bm^ bv pr bm^ pr v? bm^ bt Chromosome 6: V7 PI sm +/py x PI sm py PI sm A b Inbred II x pbx Inbred I x pbx 259 Chromosome 7 : Hs °2 v 5 Chromosome 3: msg 2i vi6 x (ms£ 3l x vl65 Chromosome 9: +/vpl̂ + /17 ms2 x ms2/+ sh wx +/ ms20 x Ms 2Q Inbred I x ar wx sh +/d^ Inbred II x c sh bp wx Chromosome 10: +/vpx + /w2 rst vlg Rmb °g Si 11 Rnj Ax C Pr Og a3 Rr& A1 C pr Pvv a3 El rr y su-l Inbred I x zb^ Nl-^/T G-̂ /? 2. Miscellaneous: ^ x dec V20 a-|_ C Rg pr in wx y at x at/+ ax C R Y pr in +/bk1 ms!l/+ bk2 +/ws-̂ a]_ B PI C R Pr V9 Ai c r Si y A c Rg su-̂ +/v^ x A B pi C Rg Pr 3cx y± lg1 +/v13 mSy x Inbred II 260 Ts6 Og ms12 x Inbred II Inbred I x bm^ ms^p x Inbred II Lo/? Hy x mg hf x +/hf Inbred II x yg^ Ts6/+ x al In In +/ tw^ db +/ba (Singl . e fs A. ton) +/rax (Singleton) mg zb f x ys 3 , No germination: Inbred II x Sx msp7 x mSpy/+ lo su^ su-l gl^ Wl/ ? wsx eh pk^ seg. fl^ btp ap B PI P ys7(Singleton) Ms3/ ? sh gx A1 RS c sh wx pr y su msi| x ms[|/+ Too late: gigas sh ar 3n XXI, Seed Stocks Received for Propagation _in_JL22. 1. P. C. Mangelsdorf, College Station, Texas:- dup d , uo se ag m. da-̂ ̂ su , DUpdU ao m seg. du-ĵ su 2. P. H. Harvey, Raleigh, N. C.: °H °H °H °H 3 . J. Shafer, Ithaca, N. Y, wx v -l glij. sh wx v^ gli| ygp sh wx seg. gll]. lg]_ 261 ON IV. Some Recent Papers on the Cytogenetics of Maize During the past year several maize geneticists have written t o the Co-op for a list of recent publications in maize. I o nf vt ih ei ws demand, what do you think of the idea of making suc l hi s at a part of the annual Maize Genetics Cooperation News Lett M eo rs ?t of the maize literature to 1935 is included in the b i cb ol mi bo ig nr ea dp hies of ''Genetics of Zea Mays" by W, h. Eyster, an S du mm Aa ry of Linkage Studies in Maize" by Emerson, Beadle, a F nr da ser. If these bibliographies were brought up to date^ a l o if s ta ll the papers published between February, 1939? and Febru , arc yo ,uld be included in the 19^0 News Letter, and all those to February, 19^1, in the following News Letter. If your reaction to this suggestion is favorable, will you help bring the following list of papers up to date (I have more than likely missed some)? Anderson, E. G. - Translocation in maize involving chromosome 5* Genetics 22: 307-313• 193*. Bindloss, E. A. - Nuclear size in plumular merleterns of inbred and hybrid maize. Amer. Journ. Bot. 2$: /38-/43. 19X- Brieger, F. G. - Genetic control of gametophyte development in maize. I. A gametophyte character in cnromosome five. Jour. Genetics 57-20. 1937* , Tidbury, G. E, and Tseng, H. P. - Genetic con- tYol of "gametophyte development in maize. II. The quarter test. Jour. Genetics 26: 17—3s• 193&* Brink, R. A. - Linkage relations in the A-Rg group in maize. Amer. Nat. 69: 283-285. 1935* Burnham, C. R. - Differential fertilization in the 3r-Pr linkage group of maize. Jour. Amer. Soc. Agron. 28: 962-975* 1f3c* Catcheside, D. G. - The bearing of the frequencies of X-ray i d nu -ced interchanges in maize upon the mechanism of tneir induction. Jour. Genetics 9 6: 321-322. 193s - Clark Frances J. - A gene for abnormal meiotic spindle formation 'in maize. Genetics 2j+: No. 1, p. 62, 1939* (Abstract). Clarke, A. E. and Anderson, E. G. - A chromosomal interchange m a ii nz e without ring formation. Amer. Jour. Bot. 22: ill- 716. 1935. Dobzhansky, T. H. and Rhoades, M. M. - A possible method for c la ot -ing favorable genes in maize. Jour. Amer. Soc. Agron. 30: 662-675* 1936* 262 p Emer ̂son R, p ^dle G. W. and Fraser, A, C. - A sul mi Rn .k a Ag .e , Beadle, rornp mary of studies m maize. Cor ln le ll A pA tg .i Exp. i. Sta. Memoir 100, ^3 p. 1935* Haber, E. S. - A study of drouth resistanc s ew ee it n c io nr bn r edZ ea g rm aa iy ns s va or f. rugosa. Iowa A. -. S. Res... 243: 55-72. 195?5. Harvev Paul H. - Hereditary variations H i G e n e nt i pc ls a nt nutrit2 ii o: n .No. 1, p. 7^. 1939- (Abstract). Jenkins, M. T. - Linkage relations of the Ag-eg factor p m aa iiz re . i n Jour. Amer. Soc. Agron. 26. 719-720. , T , uflVpo k K. - The inhe J rO in tn aS n° ct e4 nd o; f rn p; es re i cai rn p s^It c^rn. Jour. Amer. Soc. Agron. 20 (3): 220-231- 1938. Jones, D. F. - M u t a t i o n rate in somatic cells of maize. N at. P roA cc .ad. oci. 22: 6 ^ - -AS. 193° • - Somatic segregation and its relation to atyp g ir co aw lth. Genetics 22: \tSa -522, 1^3/ • - Translocations in relation to mosai . c. formrn aa ti iz oe n. inProc. Nat. Acad. Sci., TJ.S.«., (5). - • 1938. - Growth changes associated with ch - r- o- m- o- s- oma en d b rr ee aa kt at ga ec hment. Genetics 24, No. 1, p. 77. (Abstract). - variable effect of the C locus - i- n- - m- a- it zr ea n fs ol lo lc oat wi io nn g. Genetics 2it, No. 1, p. 100. U39. ' stract). TTpmnton J H - Maize as a measure of In S de ix ai n co s kiB lu li. 226: 19 . Univ. -28 New . 1936. (In symposium t oo fr i pc r ea hg ir si -culture.) - Maize, our heritage from the Indian. S Anm ni .t h Rs eo pn .i an Inst. 1936-37: 3«n-4o5. 193-• Langham, D. 0. - The inheritance of intergeneric E u do ih fl fa ee rn ea n ch ey sZ b e ia - ri nd s. Genetics 24, No. 1, P- ■ (Abstra ‘c t). n t i ndctrom E. W. - Micro ° - evp oa lr ua ts ii ot n; oi fn t he or sa tc -tions in bacterial wilt of maize. 2 4, G enN eo t. ic1 s. 1939* (Abstract). 263 IS. tone-lev A. E. - Morphological characters of teosinte chro L mosg omeJ so .u r. Agr. Res. ^4: S35-S62. 1937- T^riintock, 3. - The production of homo * zygou s defw ii ct ih e nm tu t ta in st s uc eh sa ,racteristics by means of the m i at bo es ri rs a nb tehavior of ring-shaped chromosomes. Genetics d̂ . 315-376. 1932* - The fusion of broken ends of s — ist' er ch hr ao lm fa - tids following chromatid breakage at m p eh ia os te is o. anM ai -ssouri Agr* Exp. Sta. Res. nul. 2j_), 0 „ 9 Maize Genetics Cooperation - Recent linkage studies in maize. Genetics 24: 59-63. 1939* Mangelsdorf, P. C. - Modification of M m ee nch da en lb i iy a ca nl ratios in s me ap ia zr eation of gametes. Proc. Nat. Aoau. oci. H (12): 69?5-7CO. 1931. and Reeves, R. G. - The origin of maize. Proc. NatT Acad. Sci. 24: 303-312. 193^« Mather, Kenneth - Chiasma frequencies in trisomic maize. G v eo nl e. t i2 c4 s, , No. 1, p. 104. 1939. (Abstract). Maxwell, L. R. - The mechanism of delayed killi w ni gt h o fX - mr aa id zi ea t si eo en d. s Proc. Nat, «.cad. oc-. _2j. j(( j-■ * 93 • Nemec 3. - Gold in Zea mays. Ber. Deut. Pot. Ges. 51: 1935. 0 'Mara, Joseph G. - Cytological observations on Zea-E h uy ob hr li ad os n. a Genetics 2%: No. 1, p. 82. 1939- (Abstract). Perry, H. S. and Sprague, G. F. - A second-chromosome gene, Yj, producing yellow endosperm color in maize. Jour. Amcr. Soc. Agron. 2S: 990-996. 1936. Randolph, L. F. - Developmental morphology of the cary m oa pi sz ie s. inJ our. Agr. Res. Jx3: S0I-9I0. 193-• - - --- T- h-- e- - - o c-. c urrence of _ p_ a_ r then4 o. genctic d /- i«•? p loT ide st ra inploid maize. Proc. Nat. Acad, cojci., v.noli ._ p2c5; , VO. -j ■> ; j ;% and Hand, David B. - Increase in vit T at mv in _ o Af “ ac co tr in v -c aused by doubling the number of chromosomes. S cience, JgZ, No. 2263: 442-443, 193*5. - Cytogenetics of tetraploid maize. Jour. Agr. 'Res.~3q7 7: 591-605, 1935* 264 pandolph, L. F. - A new fixing fluid and a revised sche th de u lep ar fa orf fin method in plant cytology. Stain Technology, 10 (3), p. 95> 1935* Reeves, R. G. and Mangelsdorf, P. C. - Chromosome numbers in relatives of Zea mays L. Arner. Nat. 62. o35“o 5j * -l35p * Rhoades, Marcus M. and McClintock, B, - The cytogenetics of maize. Bot, Rev, 1: 292— 325* 1935* Rhoades, Marcus M. - A cytogenetic study of â chromosome fragment in maize. Genetics 21t 491-502. 1 3 ^* _ - The effect of varying gene dosage c oo nl -- ---fone" o au lr e u- in maize. Jour. Genetics 13: 347-354. 193^* __ - Note on the origin of triploidy in maize, j — 'rjcTnetics 12: 355~357* 1935. - ■- E— f fec. t of . the Dt _ g_ e_ n_ e_ _ o_ n _ t_ h_ e_ _ m_ utabi lity of■" ' the allele in maize. Genetics £3: 377—~3Z9G~77• 11 9Q3X^R* - and Rhoades, Virginia H. - Genetic studies ------iTSTfactore in the tenth chromosome in maize. Genetics 24: No. 2: 302-31^. 1939* Singleton, W. R. - Early researches in maize genetics. Jour. * Hered. 26: 4^-59* 1935* - Early researches in maize genetics (conol.)* ** Jour. Hered. 26: 121—126. 1933* - Effect of colored cellophane on the production — ---- of sun-red color in maize. Science 74: 486-489. 193-• - Gytological observations on deficiencies pro- duced by ̂ treating maize pollen with ultraviolet light. Genetics 24, No. 1, p. 109. 1939* (Abstract). Sprague, G. F. - Random sampling and the distribution typ Pes h eno on -ears of back crossed maize, jour. Agr. 7 5 R1 e- s7 .5 8 I. I * 1935. Tavcar, A. - Beitrag zur Vererbungsart der ^pindel-fa v ri be ur nko gr an n- reihigen Maiskolben. Zeitschr. Indukt. Abstain, u. Vererbungsl. 21: 3^1-352# 1936. Thomas, K. L. - The glossy character (gUl1 in a ge relations. 2lJ io nu kr ~. Agr. Res. 44 (2). 107-175* Van Overbeck, J. - Auxin production in seedlings of dwarf maize. Plant Physiology lj: 5g7~59&. 1936 - 265 Van Overbeck, J. - "Laziness" in maize due to abnormal distribu- tioxi of growth hormone. Jour. Kered. tes 339-3^1- 1932. Weiss, M . 0. and Wentz, J. 3. - Effect of luteus genes on long- evity of seed in maize. Jour. Amer. Soc. Agron. 2.9 • ^3“ 75- 1-937 • -“-ssiuJ Mi -g iul a s. rI sowa sSt sa ste i fCo *llege, Jour. 01 Sox., fol. IX, Jo. > 1935. V. Maize Genetics Cooperation Mailing List Anderson Dr. Edgar, Washington Univers A in td ye ,r so Sn t" ., LD or u. i sE ,. MG o. . , Institute of Technology, Pasadena, Calif. Beadle, Dr. G. W., Biology Dept., Stanford. Univ., Stanford 'Jniv., Calif. Bennett, Dr. L. S., Agronomy Dept., Agric. Exp. S §L ta., FIjJ ayetteville, Briegor, Dr. Friedrich,*Esoola Luiz ae Queiroz, Piracicaba, Sao Paulo, Brazil. Brink, Dr. R. A., Genet .ics Dept., Univ. of Wi W sci8 oC nsin, Madison, Dr a M., Agronomy Dept., Purdue Uni B vr .v ,a n L aFD ar y. e tW t. eI ,f ., I nQ du .eensland Agric. Co S lla egm e,! L ewir O e. s .K ,. , Q., Au sA tg rr ao ln io am .y division, University Farm. St. Paul, Minn. Cartledge, Dr. J. L., Agronomy Dept., Univ. of West Virginia M ,organtown, W. va. riokev ,rr. Ira K. , 1635 Laurel St., c o So op ue tr h’ PDr a. s adD e. naC ,. , Unive •rsity of Wisconsin, Genetics Dept., Madison, Wise. C reighton, Dr. Harri >Te t B _. , .C o „nn. College for Women, Hew London, Conn. Dawson, Mr. C. D. R., John Innos Hort. Inst., Mostyn Roa p da ,r k, M orL to on ndon, D 0e .m We .r 1e 9c , ED nr g. l M ^. n c, .Carnegie Inst., Cold S p r i n g Harbor D .o Lr os ne gy 0 I sD lr a. n dE. , , . ..P l .ant Breeding Dept. , Corn D eo lx lt a Ut no ir v, e rM sr i. t y,0. Itr h. a, c aD iv k. . ..of Agronomy, University Farm, bt. Paul, Minn. Fokhardt R. G., Farm Crops Dept., Iowa St E am te er s co on l! l' eD gr e! , A..î s, loio.,1. A., Plant Breeding Dept., Cornell Universi It th ya , E cy as ,t e Jr ., YD . r. W. H., Botany . Dept _. , •B u ’c k _ „n ell 1 30University, Lewi sourg, Fraser, Dr. A. C., Plant Breeding Dept., Cornell University, Ithaca. N. Y. 266 mrhQT Dr. R. J. , U.S.D.A. Regional Pasture Res u earch ’ Lah., State Coll G eu gr en ,e y, P enn. Dr. H. G . ., W Ta i . te Resea . rc . h . Inst., Adelaide Univ., Adelair , Aust. Hadiinov, Dr. M. X,, Inst, of Plant Industry, Detskoe Selo (near Leningrad), U.S. H Sa .r Rve .y , Dr. Paul H., Ag nr ono . m .y Dept., University of North Carolina, Raleigh, II. C H .r yes, Dr. R. . . K. _, Agro an +omy Division, University Farm, bt. .̂.il, wofmevr Dr. J.D.J., P.0, Marabastad, Pieter H so bl ub re gr , t' SoD ur t. h J A. fR r. i, c aF .e deral Building, B H lo or oo mv ii nt gz t, o nM ,r . IlS. l, i noI in ss .t ituto de Santa Catalina, Llanallol, F.C. ., Argentina. Hull, _D r. Fred, Agronomy D -ept., Agric. Exp. Sta., Gainesville, Florida. Jenkins, Dr. M, T., Bureau of Plant Industry, U.S.D.A,, Washing- ton, D. C, Johnson, Dr. I. J., Agronomy Divis nion, University Farm, St. Paul, Minn, Jones, Dr. D. F., Genetics Dept,, ~Agr. Exp. St., Hew Haven, -onn. Kempton, Dr. J. H., Bureau of Plant Industry, U.S.D.A., Washing- ton, D.C. vrmf Mr Kenneth, F, H. Woodruff & So K nr su ,g * MiM lr* f. o rC da ,r l ^o os n nA ,., Inst, Agronomica do Estado Campinas, oao Paulo, Brazil. Kvakan, Dr. Paul, Dobricevo Cuprija, Jugoslavia. Langham, Dr. D. G., Plant Breeding Dept., Cornell Univ., Itnaca, Lebedeff, Dr. G. A./ Plant Breeding Dept., Cornell Univ., Ithaca, N. Y. Li Dr. R. . W., Wu-Ra , n Uni .versity, Wuc L hi an nd gs ,t ro Hm u* p eh,L CE nd . i naW ,., Genetics Dept., Iowa State College, toes, Lonrley, Dr. A. E., Bureau of Plant Industry, U.S.D.A., Washing- ton, D, C. McCllntock, Dr. Barbara, Botany Dept., Univ. of Missouri, Colum- bia, Mo, M ains, Dr. E. B., Bo .t a ,n .y Dept., Un . i - ve _rsity of Michigan, Ann Aroor, Mangelsdorf, Dr. P. C., Agronomy Dept., Agric. Exp. Sta., College Station, Tex M ai sl .e s, Dr. L. G., Dept, „ of Ag , ric ,. A Stock, Brisbane, Queens_an , Mumm, Mr. W. J., Agronom.y Dept., University of Illinois, Urbana,111 Neal Dr. Norman P., Genetics Dept., Univ. of Wisconsin, Madison, Wise. 267 n , q nn+artv Dpot. Duke ^ t Unn i^ vD er r sX iF t y,H D* u N ra ht ai mo ,n a Nl . R Ce as re oa , I r t ci hlv s C ouh ni c: il, OIH t. t* aF wi, a ,W a Oi nt te a rR ioe ,s ea Cr ac nh a daI ,n st., Adelaide ’ Univ. , AdelaiA du es ,t. BS««7 KB&'Rfc X & tion , S Te WRho xa ad se .s cSW-, Dr. M. M . , Arlington Exp«1 . . .Fa R ri mc sh ey A, r lM ir n. g tF o. n ,D . V, irP g. iO n. i aB .o x 23, Asnville, Ohio. St. John, Mr. R. R., Botany Dept., Purdue University, LaFayette, Sando I ndiDr a. n a,C has. E., Bureau _ of n C .h . emis Ttt r q y t \ an ad Soils, U W .a Ss .h Di .n A.Sa gn t , s oo nm ,e , D .D Cr .. F. W., Botany Dept ,. , , U .niv. of Manchester, Mancnester Shafer, Dr. John I., Botan^Dept! , S i Cn osr rh n elD lr . U nS i. v, . ,B o ^t ha an ci aca ,l KS .e Yc .t ^ion, ’ I’ mperial Inst, s oe fa r *c gh r S , - i n P • as - gle at ,o n B, e hD ar r. , W _. ndR i. a, .Geneti°s Dept., Agric. Exp. Sta. , New Haven, a^vninff P S ro ok fo lo Dff m, i trP ir ?o l. E scM ul et la^ dei t Ci ic en ni cc i0 a sN a Bc ii o0 ln oa gl i, c aM se ,x ic Io ns tC ii tt uto Spr ya ,g u Me e, x iD cr o. . G. F., Field Crops Dept., Univ. of Missouri, Columbia, Stadler, Dr. L. J., Field Crops Dept., Univ. of Missouri, Columbia, Stringfield, Mr. G. Agronomy Dept., Agri & c . Exp. Sta., O bh oi oo s. ter, Tavcar, Dr. A., Dept, of Plant-Breeding, Univ. of Zagreb, Zagrec, Thomas, Dr. H. C. , t e n l u o f & t . , University Farm, St. Paul, Minn. EES: £: Virginia, Morgantown, . va. • r n r ooq Wo«=it Beaver W i Ag vcg *a ,n s State ColD ? ! * R . *G l. eP gel ,a n Pt e. uB nr * eeding Dept., Cornell University, Woodworth, Prof. C. M., .Agronomy Dept., Univ. oi Illinois, U r b1 a1 m1 , Yasui Prof. K., Plant-Morphology Division, Tokyo I v me pr es ri it ay l, UnT io -kyo, Japan* Anrirpq Dr Jose to., Director 5 Del* InstitutoD D e Ceneq Agrono tm ii ca a ,Y FV ae ct ue lr ti an da ria, Buenos Aires, Hill, Mrs. H. H., Arlington Experiment Station, Arlington, 268 MAIZE GENETICS COOPERATION NEWS LETTER H March 5> 194-0 The data presented here are not to be used in publications without the consent of the authors. Department of Flant Breeding Cornell University Ithaca, N. Y. 269 M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A , N E W Y O R K October 31, 1939 To Maize Geneticists Call for material for the 1940 issue of the Maize Genetics Cooperation Nev/s Letters. Dead line is January 15th at Ithaca, New York. The next issue of the News Letters will contain a revised list of all the Co-op stocks. Please send us your material which in your opinion would be desirable to include in the Co-op list. Also include anything that will be of value to other maize geneticists, such as your new linkage data, etc. Members who attended the Genetical Congress at Edinburgh last summer are particularly requested to send in comments which might be of interest to maize gene^i- cists. Sincerely yours, G. A. Lebedeff Secretary 270 \ J c / . / / M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A , N E W Y O R K March 5 j 19^0 To Maize Geneticists Dr. G. A. Lebedeff, secretary of Maize Genetics Cooper- ation has accepted a position at the Agricultural Experiment Station of the University of Puerto Rico, Rio Piedras, Puerto Rico. I am, therefore, for the present acting as secretary. This News Letter is presented under the following headings I, Maize gene symbols in publications. II. General news items. III. Maize publications. IV. Inventory of Cooperation seed stocks. V. Index to seed stocks. VI. Historical Notes on Maize Genetics Cooperation. It is understood that data presented here are not to be used in publications except on permission of the authors. I. MAIZE GENE SYMBOLS IN PUBLICATIONS The following statement is quoted from a letter written by Dr. L. C. Dunn," managing editor of Genetics, to Dr. L. J. Stadler, a member of the board of editors:- "The chief difficulty from the standpoint of publisher and printer comes from the frequent em- ployment of subscripts which as you know have to be set in by hand and sometimes require special characters to be cast. This represents extra cost to the journals. If it is absolutely essential it must be done, but I’m not convinced that it is essential. In the present paper A1 would serve as well as Ax etc. except that the habit of subscripts has crept in through use. Jones had a rule against them but I notice that he didn’t enforce it in Emerson’s papers and I haven’t either. There’s no avoiding superscripts for multiple allelic series, but subscripts aren’t generally essential and when both are required, e.g. A^, the system approaches physical limits for the compositor and looks rather absurd. I don’t propose any sudden revolution. I do suggest it might be discussed by the maize group, 271 keeping in mind that a system needn1t necessarily be frozen by the first ten years of use and that economies in publication, if done without harm to clarity and preciseness, give our journals greater stability and security for the future.” Dr. Dunnfs example illustrates the confusion which might often result from following his suggestion. Arabic figure "l” in typed manuscript cannot be distinguished from l.c. letter ”1". The symbol "al” might be read "a-one" or "albes- cent If the literal part of the symbol were always itali- cized and the numerical part not italicized, there need be no confusion. Or, if the numeral is joined to the letter by a hyphen, there should be no trouble. Again, if the numeral could be set in smaller type than the literal part of the symbol, the printer’s problem might be solved, but certainly not the typist’s. It seems likely, however, that two sizes of type might be as bad as subscripts for the compositor. In a recent personal conference with Dr. Dunn, he suggested omitting the numeral "1" in all cases. No numeral would then indicate either that there is only one gene with that literal symbol or that it is the first one reported. Thus, we would have a (= ax) a2, a3, etc. In order that you may see how you like it, the latter plan is followed throughout this News Letter. Let me know what you think of it. The principal difficulty noted in its use here appears first in Anderson’s Table (p. 3) where gl3 = glossy 3 not golden 13. In the inventory of seed stocks 17 is not seventeen but luteus 7« Perhaps a period would help, thus: gl.3 anĉ i«7* R. A. Emerson II. GENERAL NEWS ITEMS California Institute of Technology, Pasadena, California 1. Translocations involving the left end of chromosome 1 Cytological Linkage map Translocation position position Tl-2c S .7 T 1 sr ts2 P l~9o S • 6 ts2 P 1 T l~2b s A ts2 P k rn l-6c s .3 ts2 F 9 T l-3a S .25 ts2 P 21 T 38.1 br l-9a s ts2 P 20 T 38 br l-5b ts2 P 2^.^ T 32 br l-5c ts2 P 23.6 T 25 br Tl~9a is known to be in the short arm from tests with homozygous T. Location of br is probably about L .3. The spindle attachment may be near the map position of as or between as and br. 272 2. Translocations involving chromosome 4. Cytological Linkage map Translocation nosition position T4~6b S .2 Near Ts 5 J T 9 su 4-7 S .6 su + 1.5 lt~ 8 S .6 Near Ts5 and su 1-4 Near Ts5 and su i(~5o su + 1 4-10b su + 5*5 4~5d L .2+ su 1 T Tu 4-6a L .2 su k .5 T Xl+,6 Tu 2~4a L .4 su 3.6 T 13.9 Tu 2-4c su 9.1 T 30 Tu 2-4d Near Tu 2-4-b su Tu gl3 15 T It-9b L .6 su Tu gl3 21.9 T Not listed above T4~5a, 4-5b, 4~6c , 4-Sa The spindle attachment is probably somewhere near su V n. inripTRrm 3, Translocations involving chromosome 2. Cytological Linkage map Translocation position position T2-3a close to Ig 2-3e close to lg 2-6b s .75 gl2 It.2 T I.It B 2- 3c gl2 B 0.5 T sk 2-9a S .65 Near sk l~2b S .6 Near sk 2-5 B 4.7 T 6.0 ts 2-3d sk 5.5 T 12.6 v4 2-4d sk 25.4 T 5.5 v4 2-6a B 43 T 1- 2a T 11 v4 (Brink & Cooper) 2- 9b s .1 ts 5.3 T 7.S v4 2- 5a L .1 sk 17.1 T 7.5 vlt 2-5b ts T vlt 2-10 L .2 ts ll.lt T 6.6 v*t 2~7b L ,25 ts 15.3 T 5.It vlt 2~7a L .3 ts 7.2 T 1.1 vlt 2-6 ( 7« ) sk T 1.5 vlt 2-6c L .3 ts ll.lt T 1.6 vlt 1- 2o L .3 ts S.3 T 1.1 vlt 2~4a L .3 v4 + 1.5 2- 6d L .4 vlt + 5.0 2-7c L .3 + ts 13.5 vlt 1 .1 T 2- 3b ts Itv 4.0 T 2-4b L .6 ts Itv 5*6 T 2-4c ts vlt 19.0 T 29.2 Ch The spindle attachment appears to be about half way between t s and v4. E. G. Anderson and I. W. Clokey 273 Division of Cereal Crops and Diseases . U . S . D . A . .Washington ,0^0^ 1. Crosses were made in which pollen was collected from individual flowers located in white and green sectors, re- spectively, of the tassels of iojap plants. The pollen from each flower was used individually on the silks of a plant of an inbred line. The F2 progenies of these crosses were ob- tained and grown to determine whether pollen trom flowers of the two types of tassel tissue differed with respect to transmission of the iojap character. No differences of any kind could be observed between the F£ progenies from crosses made with pollen from the two kinds of sectors. 2. Data obtained on a ^-point backcross involving 3039 individuals indicate the following order of the chromosome 7 genes involved:- o2 2,2 y5 2.0 ra 2.4- gl Data obtained on a 3-point backcross involving only 132 individuals indicate the order of the three loci involved to be as follows 12.2 3n 37-5 M 3. In 1932 one of the selfed ears obtained from a selfed line previously inbred for 6 generations was segregating for sugary seeds. Since tnere was no evidence of out—crossing and none of the ears from numerous sister plants selfed in 1932 and in the same progeny replanted in 1939 from remnant seed segregated for sugary seeds, it seems certain that the sugary gene arose as a mutation. Crosses made in 1939 identified the mutant gene as su. M. T. Jenkins lj.. Deficiencies. A v2 deficient plant from X-rayed pollen had a small internal deficiency in the long arm of chromosome 5 near the knob probably proximal to it. A B deficient plant from ultraviolet treated pollen had an apparently terminal deficiency of 2/3 to 3/^ o f the short arm of chromosome 2. 5. Translocations from ultraviolet. In a population from pollen treated with ultraviolet 9 decidedly off-tjpe plants (in addition to marked deficiencies) were examined. Presumably all were deiicient, though the deficiencies were not marked. The diakinesis configurations were as follows: 5 plants had 10 II, 2 with obvious deficiencies. 1 plant had 2 II and a ring of a typical interchange complex. 1 plant had 7 II and an open complex of undetermined number. 2 plants had 2 II and a 3 chromosome open complex. 274 In each of these last two plants with a 3 chromosom c eo mplex a chromosome bridge was frequently seen at ana I phaa sn ed segregations of 10-10, and cj ~ I l were ob T sh ee r ved di .akinesis configurations and anaphase segregations c b ae n explained on the hypothesis that two chromosomes t we ir tm hi nal deficiencies have united to form a single c s ho rm oe m ow -ith two adjacent centromeres, the terminal p h oa rv tii on ng s been lost. This hypothesis depends on the assu t mh pa tt i os nu ch a chromosome could persist through the life of t e plant* Lillian Kollineshead Hill 6. Summary of Ws3 - Lg - iri2 backeross data. Fi genotype 0 1 _ 2 __ 1> 2 Total + 4- + 737 303 82 88 1^6 165 3 2 2001 ws3 lg gl2 8.2$ 0.2f These three loci are all in the short arm of chromosome 2. A high degree of interference is indicated by the coincidence value 0.15* 7 . Summary of Bm Bt Pr backcross data Fl genotype 0 1 2 1, 2 Total + bt pr 133 *162 0 3 92 260 2 2 972 bm + + 1 .13* 37. c M Bm-Bt = 1.5$ Bt-Pr = 37-!% The inequality of the complementary classes is due to the poor germination of bt seed. Summary of Bm Bt backcross data Linkage Genes Phase 3m Bt Bra bt bm Bt bm bt Total $ Re corab. Bm Bt R B 11 359 900 3 127g The inequality of the complementary classes is due to poor germination of bt seed. 9. Linkage of Dt with loci in chromosome^ 9. Data pub- lisned in 193$ suggested that Dt was linked with . To test t Ch is indication the following data ere obtained: Linkage Genes Phase XY xy xY xy Total fo Recomb. Dt Wx C S 1663 825 690 110 2996 Ill Dt Wx C B 602 fl-65 1+72 677 2296 4-0.3 Dt Sh C S 679 100 156 130 1073 27 275 These data definitely prove that pt is in chromosome 9 f ur at nh de r indicate that Dt should lie with yg2 close to ;yg2. Tests have been handicapped by the fact that all ava able vg2 il- stocks are homozygous for recessive c and it has been necessary to extract a yg2 C stock. 10. Effect of varying dosages of Dt. Previous d h aa tav e shown that a non-linear effect was obtained when f de ir fe -nt dosages of Dt were present in the aleurone. Ho t wh ee v ed re monstration of several modifying factors affec a t- iD nt g r te ha ec tion made it necessary to secure data oeari t nh gi s o nr elationship in an iso-genic stock. Such an s it so oc -k g enw ias c obtained through repeated self-fertilization D t ofd t a stock — heterozygous Dt dt seed being used m g ee ven re yr ation to further the inbreeding. Af 5 ter 5 yearss e ol l fing the F seed was classified into Dt Dt, Dt dt and dt dt classes. For the dosage relation between 1 g ae nn de s 2 pe tx act reciprocals were made between pi; pt and p al ta n at ts . It was necessary to self Dt pt individuals to t 0a 0 in data on the effect of 3 Dt genes. The following data were obtained: Mean number of mutations in Pedigree Dt dt dt class Dt Dt dt class Dt Dt Dt class (1 Dt) (2 Dt) (3 Dt) 613U—13 x 6131-7 6.8 19.5 reciprocally 6134-6 x 6131-14 5.9 19.6 reciprocally 6134-1 x 6131-2 7 .S 19.9 reciprocally 6134-2 x 6131-9 9.1 23.9 reciprocally 6325-25- x 6326-13 6.7 24-.9 reciprocally 6325-9 x 6386-19 8.3 26.6 reciprocally 6385- H x 6390-17 8.4- 24-.1 reciprocally Mean ratio for 1 Dt : 2 Dt - 1 6131-12 selfed 110.1 6131-8 selfed 126.7 6386-2 selfed 128.7 In each determination at least 50 seeds were used. fig Thu er es represent the average number of mutations (i o .f e . co dl oo tr s) in the aleurone layer. The mutation frequ t eh ne c y3 iD nt class is too low. With such large numbers p er o f se doe td s there is considerable overlapping of the m a ur te aas n. t Error also enters from the fact that an earlier t mi uo tn a -of one a allele will obscure a latter mutation s ec ofo n ad allele. In the case of 1 and 2 dosages of Dt this is 276 an insignificant matter but it must be taken c ino tn os id ace cr oi un ng t t ih ne data from 3 doses of Dt. Due d toi ff thi ec u el xt ty r ei mn e counting the dots on the 3 e a Pr Js i cw le ar se s c oo nu ln yt e 3d . They were in no way d n iu fm fe er ro eu ns t u fn rc oo m un tt hee d ears of the same constitutio c no .n fi Tr hm e st eh e o ae ta ar lier conclusion that the effect of v d ao rs yo is n go f the IDt allelG is a non-linear one. 11 Effect of temperature on mutation rate w oh fe n a p al la ln et ls e were matured at two levels of fe tr et mi pl ei rz aa tt ui ro en . a fteP rl ants of a Dt constitution we t re em p ge rr oa wt nu re a t o af approximately 70 degrees I m Fm .e d ui na tt ie ll y fla of wt ee rr i np go .l lination they were divided i n at to rt aw no d ol mo ts and one placed in a greenh a or uo su en d m a6 i0 n td ae ig nr ee de s _F . and the second lot pla i cn eg a h io nu s ae n m aa di jn ot ia ni ned at or near 80 aeg. r. T p nel an tt ws o w le otr se ol fe ft at the two temperature w la es v er li sp e un ne td i. l sT eh ee d mutation rates at the two te we mr pe e rad te ut re er sm ined by counting the number of a T lh ee u ra ov ne er a dg oe t smu .tation rate was determined n bu ym b ce or u no tf i ngd ot ts h e on fifty seeds of each ear e ea xr cs e pm t ar fk ore d tb hy o s.a sterisks where less than fi.ty s a ev ea di sl a wb el re e. The data obtained are given oelow: Mutations per seed Pedigree 60 deg. F. SO deg, r 6279 x 6329-2 5i 0.2 2.9 I 7.2 9.0 It 11.5 x 6329-3 .5 9.9 I l \1.2 x 6329-1 44.9* 14.5* x 6329-6 29.5* 13.9 Total 250.6 65.0 Mean kl.& 9.3 The results listed above are somewhat asto t no i st hh ie n gw r ai nt de r entirely unexpected. A simil b ae ri ng e xpc eo rn id mu ec nt te d ist his year on a more extensiv s ea m se c a" le ef .f ect I i is t hf eo und it should be possible c tr oi t di ec ta el r mp ie nr ei o td n ea t which the temperature chang f ee ct h. a s iI tt s a el fs -o will permit inferences, or if you g wu ise hs ,s es, as to the nature of the a— Dy. reaction. 12. Mutation of a to different allel o ef s .m uta Tt hei on f reo qf u er ne cc ye ssive a in the presence of Dt to th a el le a le as compared to tne frequency to t c ha en Ab e a na ds c Ae rt aa li ln ee ld e sb y the classification of d o tt ns e i an lt eo u rp oa nl ee and deep colored. However i i ns ti nm ep o as ls ei ub rl oe n et o i td ifferentiate between t a hn ed At o a nd ae t Ae rm ai ln le e lt eh se relative frequency of mut t aw to i oa nl le tol es t hei st e is necessary to test the relatively rare 277 germinal mutations against the P gene. To date twelve m gi en ra -l mutations giving deep colored aleurone and purpl p el ants, with B PI, have Been tested, eleven proved i de ton ti Dc e al to the A allele while the remaining one gave drown pericarp. Since Ab produces a dominant brown peric w ai rl pl t)0 it necessary to test this allele against A in order f ti on d if the brown pericarp color is dominant to the A r eb de of for e one can draw the conclusion that it is a mutation to A®• Irrespective of the outcome of this test it a il sl e al ne different from A and aP and mutations of a to three different alleles have occurred. There are only two a alleles of different origin. Bot o hf these are mutable in the presence of Dt. It is in oft er se os met that on four occasions mutations of an a alle u ln es table with Dt have apparently occurred to an a alle w lh ei ch is stable with Dt. Stadler has found an a al s lt ea lb el ^e with Dt which arose as a mutation in his ultra-violet treatments. 13. Linkage of reverted A alleles with lg2. f Fe our re nt d ifg -erminal mutations to A have been tested for li a ng ka ai gn es t lg2. As expected all four showed approxim p ae tr ec le yn t 3 0 recombination with lg2. All evidence available di ic n-ates that the changes occurring at the a locus are true gene mutations. Effect of Dt on Pvv. Plants heterozygous for Dt a nd carrying the variegation allele for pericarp c b oa lc ork cr wo ers es ed by dt p individuals. The Fx seed was clas i sn it fo i eD dt and dt classes and the ensuing ears graded for e g va at ri io -n in a way similar to that employed by Emerson m his s tudies on variegation* The data are as follows: Dt seed dt seed Number Mean variega- Number Mean variega- ears tion grade ears tion grade 23 4.09 34 4.12 22 4.09 19 4.05 22 3.S2 31 17 $ ? . .1 S8 711 4.36 32 4.06 35 4.00 30 3.67 36 3.6g 21 4.67 26 4.66 Total 167 190 Mean 4.os 4.11 These data show there is no effect of the Dt allele on the unstable pericarp gene. 278 15. Further studies 1 9 w3 ith chromosome 10* Lg o) n gd li es yc o (v 1e 9r 3e 7d > that certain strains of maize t eo ass in wt ee l l ha asv e an abnormal type of chromosom f er om 1 0.t he Itn or dm ia fl f eri sn that it has a very consid c eh rr ao om la et i pn i eca et ta o ched to the end of the long ar l mo .c us S io nf c eR ti hs e known to "be in the distal 22 p 1 erl 9 co en ng t ar ofm T ts ntadler, 33 e ) it should be pos t sh ie b la em o tu on t d -^of e rmr ie nc eo mbination between R and l to nn e g ea nr dm ofi f tht eh e extra piece is used as a w ma as r kek ri .n d e Drn .o ug Lh o nt go l eyf urnish a strain with the ab H ni os r ms at lr a ti en n tp hr .oved to be homozygous for rec r ea st si io v e o If 1 a nH d a! l r resulted when pollen f s rt or ma i tn ws o o df i fH fer r enc to nstitution 'was applied. Plan c to sl or fre od m se the ed s of each F-, , heterozygous f a ob rn o br om ta hl Rt e an nt ah , thw ee re backcrossed reciprocal w li yt h b yn o rr m ta el s tc eh rr so mosomes 10. The following resul t ta si n we ed r e (s oi on -c e the two Ft 's gave simil c ao rn s ri ed se ur le td s t to hg ee yt h ae rr e) : W&en the Fx plants were f uem sa el de asp ar te hen t the ratio of R : r was 26 J6 : r ec ^2i 1p 4r o wc ha il l eg a tv he e close to the expected 1 : s 1 ho rr at ta ig o.e of T nR e seeds suggests that the norma f la i cl hs r ot mo o sb oe m ei n Ic Ql uded in the functioning meg a ar se p oa rt e .l eas Tt h ert ew o possible explanations: (1) a cm oo mn pg e tt ih te i om negaspores so that one with d te hv ee l ao bp ns o rmi ant lo tt eh ne embryo sac irrespective of i t th se pl oi sn iea tr i ont et inr ad of megaspores or (2) se a lt e cm te ii vo es i ss e gs ro e gt ah ta it o n the basal megaspore receive t se nt ah n. abnO on r me ai lt her basis, if there are no c el xa cs es p tir oe np sr ,e se tn nt es g crossovers. There was no ea r s tp er ro iv li in tg y t oh na t t het he abortion of r megaspore c se p ct ae nd n oa ts ba en ae cx -planation. Studies are under t h we a yc a tu os e d eo tf e rt mh ii ns e unusual ratio as well a r s ec to o mb ai sn ca et ri to an i nv a ol nu ee between R and the end o I fn tc ho en n le oc nt gi o an r mw .ith the latter problem it is ap t pru ae r enl te ng tt hah t of t hea genetic map can never be l hi an dk a fg re o m st ou rd di ie ns a rb ye cause one never knows how o v me ur c ho c cc ru or ss s ib ne gy ond the most distally place It d i ls o cuo sn ly s tw udh ie en d .cytological markers are used, kn so ub cs h, ast ha tt e rmt ih ne alt otal map length can be m a eal sr ue ra ed dy . bee Tn h ia s cc no asm plished for the short arm o b f y cC hr re oi mg oh st oo mn e. 9 This investigation is being conducted dy Virginia H. Rhoades. 16. Crossover values in male and female fl i oe ws e ro sn , th se t uf dr -equency of crossing over for of d ic fh fr eo rm eo ns to m re e gi5 oni sn mega- and microsporocytes t i hn au ve ed . b eeE na r cl oi ne -r work by Emerson and Hutchi E sy os nt ,e r, S taC do ll el ri ,n s and Kempton, and Rhoades sh ao nw dn Rn ho o ac do en ss i hs at ve en t difference in crossing ove s ro me fs o r 2, c hrok 9 mo9, - and 10 in the male and e fv ee mr a, l e a fc loo wn es ri sd .e rab Hl oe w -amount of data have bee w nh i ac ch c ums uho lw a tet dha t this does not hold for chro d ma ot sa o mp er ov 5e . th Ta ht e sei n the male flowers the fr in eg qo uv ee nr c y^i os f gr ce ra ot se s r than in the female. Because of ease in 279 classifying most of the data are for the a2-bt region. Two different stocks have been used. In one of them a relativ h ei lg yh amount of recombination occurs while in the second stock a much lower value was found. The difference between the high and low stocks is not known but in both higher crossover values in the male flowers was found. Exact reciprocals were m ade in obtaining male and female crossover percentages. Summary of high a2-bt line (10 pairs of reciprocals) A2 3t A2 bt a2 Bt a2 bt $ Recomb. Male 1156 4-20 M k 1103 27.0 Female 12S4- 256 Z J t 1290 17.2 Summary of low a2-bt line (16 pairs of reciprocals) A2 Bt A2 bt a2 Bt a2 bt $ Recomb. Male 2 3^ 373 4-10 2590 13*7 Female 1502 110 120 1S27 5.3 In addition to the above data on the a2 jot region, data have been obtained on tne a2 bra, bra Rn and ot ru; regions. T here is a consistent and highly significant increase in crossingover in the male flowers for all ol these regions. The data also suggest that the greatest reduction occurs in those regions adjacent to the centromere, i.e. there is a proportionately greater reduction in the a2 bm and a2 b r te gions than in the bm Rr and bt Pr regions but, owing to the difference in length of these regions, this point has not been statistically established as yet. In order to determine if the crossover difference for the two sexes found for chromosome 5 is a cellular charact i es rt -ic affecting all chromosomes indiscriminately or is pecu- liar to chromosome tests were made involving the c region in 9 and the bm or region in 5 simultaneously. No difference in crossingover in the two sexes was found for the c wx region. M. M. Rhoades Connecticut Agricultural Experiment Station, New Haven, Conn. 1. Further evidence indicating a physiological change c el il n activity resulting from breaks and rearrangements of chromosome parts has been obtained from the paired mosaics th me endosperm. In the majority of cases of paired losses o C f and Pr, C and Su, Pr and Su, no change in size, arrangement or numbers of cells is apparent. In a few cases marked changes in some or all of these respects are noted. In t s ha em e material one part of the paired mosaic area may be af- fected, in other cases the other part is affected. T m he ia sn s that many chromosomal rearrangements are without any effect upon cell activity other than the subtraction of the 280 usual action associated with the dominant allele. Inthe few cases where profound physiological alterations occur it seems apparent that specific places of breakage and reattachment are involved. If the alteration resulted from a shift of growth-controlling regions of the chromosomes or a general unbalance in amount or kind of chromatin material, paired alterations showing the changes in growth would be expected more frequently and both parts of the paired mosaic areas would be affected. A few cases of this latter type are noted but they are not general. 2. Height of plant is noticeably affected by shading. Short plants grown between tall plants at the time of rapid elongation are usually taller than when grown in an unshaded location. Several lots of hybrid sweet corn grown under tobacco shade cloth were taller than the same lots grown in the open. Some inbreds seem to respond to shading more than others. Iowa Kr (Osf) (from Lindstrom) grown between two first generation hybrids was taller in the middle of the row than at either end. Height graduated evenly from both ends toward the center where there was the most shading. Heignt is also affected by time of planting. Plantings of the same lots of seed at weekly intervals usually show the second planting to be taller than the first. This also may be due in part to the shading of the later plantings oy the earlier. D. F. Jones 3. Recessive sun red. A sun red that segregates as a recessive waB obtained from a Whipple swee 5 t0 corn inbred, £ -1 7. The color is intense, is sun limited, and the stock has wine colored silks, and red glumes and anthers. Ip. Sectorial sun red (Genetics 2^-:10£) induced by ultra- violet pollen treatment, is changed to sectorial purple when crossed by dilute purple A b PI. Also sectorial sun red shows a linkage (F^ data) with gl2 and va. C.O. percent gl2 and sectorial sun red = 19; between vb and se 3 c2 torial sun res. = $. These values approximate the crossover values with 3, 19 and 21 percents respectively. This is evidence the recessive sun red represents a change from the original n faotor that was treated and is not another independent fac- tor acting upon the 3 gene. This character is being studied further. 5. Effect of female stock on the functioning 1 9 o3 f s£ pol-len. In S pollen of sp su/ + + plants was put on two su inbreds Purdue 39 and Connecticut cl. The _su sceas ootained (the crossover class with no sp survival) were 39 percent for P39 and 17$ for C£l. These figures are both too high for the crossover value (6$), and suggested the possibility that the two sweet inbreds had influenced differently the functioning of sp male gametes. Pollen examination of plants produced by these two pollinations verified this assumption. The su seeds from the P39 cross produced plants, £71° of which 281 were segregating for up. There was only 5bŷ Oi segregating plants from the C$1 cross* By correcting the original hcrossoverM percents for ssu and sp in order to eliminate up survival in the pollen, the true crossover values of 5*1 and 7.4- are obtained. These are both close to the &/c ^value 282 is controlled by a single recessive factor, and evidence in- dicates that it is located on chromosome 2 at approximately 2 5 crossover units from the B factor and 4-5 crossover units from lg. L. M* Roberts Cornell University, IthacaJLlX. 1. In tetraploid maize unimodal curves were obtained from hybrids between self— fertile and self—sterile lines back— crossed to the self—fertile parent; in the oack—cross to the self-sterile parent a bimodal curve was obtained, 250 or more individuals being involved in each population. In the F2 population of the same crosses unimodal or very weakly bimodal curves were obtained. The F-i of the incompatible matings between the self- compatible lines (B lg and su) of tetraploid maize repo i rn tet dh e last News Letter was found to be selx-fertile, a t nhe d back-crosses to the parent lines wore also compatible, as indicated by observations on 50 01 more ears from each cross. A n incompatible mating bet?;een the cross—storile 3 lg line and a self—sterile B Lg line showed an intermediate degree of self-fertility (37f) in Ft . The backcross to the B pa lgr ent was 3 7 compatible (26 ears) while tne bacx—cross to the B Lg parent was only 15 perce - n- t- compat* i* ble.Harold E. Fischer 2. Monosomlo Maize. A plant monosomic for one of s th ho er ter chromosomes ""Tundetermined) appeared as a partheno- genctic diploid in a tetraploid stock of maize. A detail s et du dy of meiosis with special reference to tne behavior of the univalent was made. Tne univalent 77 i0 n fifty percent of the cases observed was found to go to one of tne pole i sn division I. In the remaining cases the univalent was n i on tc luded in the daughter nuclei of division I but remained in the cytoplasm forming a micro-nucleus. Most (+/*] ot these free dvad univalents were apparently reincorporated into the spindle of division II. This was indicated by a m arked reduction in number of free dyad groups in metaphase II as compared with the frequency of micronuclei at inter k -i nesis. Such cells produce microspores with a normal chromosome complement. In cases where tue dyad univalent ̂ fails to be reincorporated in the spindle of division II, o f it te n forms an independent spindle and divides,^ As a rosult o f this, microsporcs containing a micronuclous in addition to the macronucleus are formed (in l,3f? of tne microsporc T sh ,e . univalent was observed to divide in 10% of the first division figures. The resultant chromatids do not divide again in the following division but lag or move to one of the poles giving a 10—9 distribution in anapnase 1^* Pollen e xamination shows that 5'M0 grains are abortiv p er ,e s du um eably to lack of a full chromosome complement. Selfm o gf the monosomic plant resulted only in diploid progeny and 283 the same result was obtained when it was used as a pollen parent with normal diploid plants. Harold E. Fisoher and John Einset 3. Vivipary designated as vp5> found in Dr. Wiggans' cultures, is closely linked with yellow endosperm, as can be seen from the Fg data presented below. If it is Y, which it probably is, then vp5 is located in chromosome 6. Classifi- cation of vp5 is good. In cultures where germination has> gone too far resulting in discoloration of kernels, classifi- cation of endosperm color is difficult. Last summer's data in regard to pb-x confirm the previ- ous observation of its close linkage to Y, as shown below. Four pb genes are listed in the Linkage Summary, all of them have been lost. Therefore pb-x will be designated as pb5 although it has not been tested for allelism with the other four. Backcross data for vp5 and J2)25 follow: Genes Phase XY M xY xy Total $ Recomb. Vp5 Y CB 14-89 35 33 203? 3.3 Pb5 Y GB 231 l 2 250 0.6 G. A. Lebedeff k. Backcross data involving chromosome 7 . Of the three cultures included in the tnree-point test, the first was grown in the greenhouse in the winter of 1936~39> the second in the garden in the summer of 1939> bhe third in the greenhouse in 1939-4-0. genotype 0 1 2 1 , 2 Total + v5 gl 1 6 9 0 - 1 6 6 1 137-4-g 254-296 7 1 - 2 1 4lS0 in + + 1 2 5 8 - 1 2 5 3 7 2 - 3 6 1 3 7 - 1 3 4 6 1- 6 2062 1426-1362 _8Z-52 220-230 lZ-_6 ^4u 1 4-374-4261 296-137 6 1 1 - 6 6 2 169-33 10 563 S655 433 1273 . 202 4.1$ 1 2 .1$ 1 .9$ The marked difference between complementary classes of region 1 and double crossovers are not to be accounted for by differential viability of recessives; for, of the total, in plants constitute 445.4$, y5 pl 5 a0 nts 4 S , a n d g l plants .I$. A comparison of frequencies of double recessives with those of corresponding double dominants shows that the one double recessive, in v5, is principally responsiele for the differences between complementary classes. The frequency relations of double recessives to corresponding double dom- inants are as follows: 284 In V5 100 In Gl 100 Vp 01 100 in v5 37 in gl gg y5 gl 99 In view of the approximate equality of V5 and v5 plants in this back-cross progeny, it is hard to account for the^ deficiency of in y5 plants either on the basis of errors in classifying or a suppressing effect of _in upon the expression of v5, like that of R upon j. A further study will be made of this second possibility. A two-point back-cross gave the following: Phase In Tp In tp in Tp in tp Total $> Re comb,., CB 14-7 65 60 124- 396 31*6 The order of these genes is: in 6 y5 1^ £l Tp A. C. Fraser 5. The gsh reported last year is allelomorphic with g4. 6. mg often is completely germless. FgS of one cross contained many germless or even completely empty seeds and few truly mg ones. Fps of another cross had many fewer non- viable seeds and many truly m£ ones, mg seeds are definitely slower to germinate (many never germinate) than normal seeds, and their plants seem to mature 7 to 10 days later than plants from normal seeds. However, the mg seeds produce normal sized plants. 7 . Several crosses have produced seeds with purple plumules. From Fg counts it seems that at least 3 a^d per- haps 4 dominant complementary genes are involved. Classifi- cation of Pu seems satisfactory in yellow or white seeds. g, sb continues to be abnormal. Many sb plants last summer had stiff, very narrow leaves. In some cases these consisted of little but midrib. Plants with such leaves were usually sterile. Pollen was obtained from two for crosses. Ratios in sb crosses were again atypical. One F^ contained 177N:34sb '(5:1). Several back-cross cultures contained: Culture Sb sb 1 4-0 30 2 4-6 36 3 50 31 4 53 3° 5 45 46 Total 173 John Shafer, Jr. 285 My presence in Europe last summer had, it turns out, a deleterious effect on my summer’s work at Ithaca - a result not un~fore-seen. For such results as I am able to report, I am indebted to Dr. Lebedeff who did my work in addition to his own. 9. Tassel-seed 3 and tassel-seed 6. - In t 2 h3 e News Letter of March , 1937 (p. 6), Lindstrom reported Ts6 as about 26 units from gs. At about that time I had found that Ts3 ^cl- an were closely linked. Since an and gs are about 27 units apart and since both Ts3 and Ts^Tare dominant genes, it seemed possible that the two were alleles. Data obtained^ during the past summer though not wholly satisfactory indi- cate that Ts3 and Ts6 are not allelic. The data follow, (see also Lindstrom1s report in this News Letter.) F-j genotype 0 1 2 i _̂2 Total + Ts3 + 62-70 17-0 5-22 7-0 an + gs 132 17. 27 7 ^ 183 9.31° 1 3 . ^ + + Ts6 S5-37 16-6 13- 7 10-5 an gs + 95 22 20 1 15 . 152 13. 2 $ 3 . % + Ts3 + 59—26 10-1 lg-2*4- 2-1 an + bm2 S5 11 *1-2 1*4-1 7.g?0 29 .Sfo 2.11° + + Ts6 81-4-1 23-4 5- 0 0-0 an bm2 + 122 0 154 17.5* 3-3^ If taken as they stand, these data indicate that JTs3 is between an and gs, while _Ts6 is to the right of gjs and prob- ably to trie right of bm2. It will be noted, however, that homologous recombination classes are far from eQual. The first entry of the table shows a considerable deficiency of Ts3 plants and the second entry exhibits a similar deficiency of an plants. In the third and fourth entries, respectively, Ts3 and Ts6 are in excess of 50 percent, while ^n and bm2 are deficient. But such evidence as is available, if any, sug- gests that TsJ is near an and Ts6 near bm2. 10. Locus of knotted. - In the News Letter of March 26, 193& (p. 5)> Bryan reported Kn 26 units from br and 2*4-̂ units from bm2. These data suggest that Kn is between an ana gs. The few data obtained last summer are in agreement with this indication, as follows: 286 genotype 0 1 2 2 Total + Kn 4 49-32 c;- lk 0-0 2-1 an + gs 01 23. s 3 „ 115 20. Ofo 7.0 fa 2.6* 4 Kn 4 56-hh 26-7 2 k - l k 7-0 an 4 bm2 100 33v 3s ^ 7 _ 170 l&.&jo 21.3$ 3.9 $ If, as is suggested above, Kn and Ts3 are between an and its and Ts6 near bm2, Kn should show much closer linkage with Ts3 than with Ts7). This is borne out only in part by the following back-cross data. XY xY XI Kn Ts3 3 9 16 2 16/30 = 16.7^ Kn Ts6 0 27 ^7 13 21/95 = 22. if. 11. The order of br f an . - There were published in the Linkage Summary 1935 Cp* 35 )> three-point tests^involv- ing 960 individuals which indicated that the order is as given above. Bryan, in the 193^ News Letter (0. 5) > report- ed four—point tests with 293 individuals involving br, f, Kn, and bm2 which indicated that f is to the left of br. An attempt was made last summer to check this situation. A total of 1352 individuals were noted, but only 34 per cent of them were recorded as f. Moreover both orders of the genes indicated double crossovers as more numerous than singles in one region and equal to singles in the other region. It is obvious that many f plants were recorded as normal. This is not unlikely in cultures such as these in which f was poorly expressed. It seems likely that plants recorded as f were certainly of that nature. The following data, therefore, include only the f plants. Fl genotype 0 1 2 1 . 2 Total 4 4 4 347 22 77 „ 7 ^53 br f an 4.g $ 17. of* 1 .(A 12. Further data on chromosome 1 translocations. In my paper on zl (Genetics 1939, P* 3$2), in which many previous- ly unpublished data from Anderson were used, it was shown that Tl-5b, l-5c, and l~3a have their breaks between P and br, and that the Tl-2c break is near sr. A few further data are now available, and are presented in the accompanying table. 287 - IS - F-j genotype 0 1 _JL io_2 Total Tl-2c + + 6251 23 201S 0 2 + sr P 113 5 3s 2 15s 3-2 i 24.0$ 1 . 3$ + p + 99 112 17 22 1 ,5 0 2 sr + Tl-9c 211 39 . 6 2 25s 15 .1# 2.3$ o.g$ p + br 30 21 1 4- 12 17 0 0 + Tl~9c + 51 5 29 0 85 5.9^ 34 . 1$ Tl-2c + + 16 22 23 21 3 g 3 0 + br an 38 44 11 3 . 96 45. 1 1 . 5 1° 3 . 1 $ + + Tl-5b 59 4-0 2$ 19 g 12 3 , 1 sr P + 99 47 _ 20 4 170 27 .&fo 11.2$ 2 A # p + br 52 60 11 g 16 lg 1+ 1 + Tl-5b + '1 1 2 1 9 . 34 „ 170 11.2$ 20.0$ 2.9$ Tl-3a + + 7 5 54 28 53 13 15 12 3 + br an 12 9 SI 2S IS 253 32.0$ 11.1$ 5 .9$ Tl~9b + + 26 35 1 2 10 1 5 0 0 + br bm2 61 0 S9 2S. 2 $ Although these data are not wholly consistent, they indicate that Tl~2c is near sr and to its left, that Tl-9c is near P and to its right, and that Tl-9b is near br and probably to its left. 13. Tests of miscellaneous genes with chromosome 1 markers. - Six genes, not previously linked, have been-tested with several loci of chromosome 1. On the next page are shown the number of individuals and per cent of recombination in each F2 test. New sr m sl7 P br an gs bm2 genes no. A no. 'jo no. i no • yo no. no. $ no. at 14-9 5° 113 4-2 149 51 49 60 4-9 60+ na2 17 42 4-7 ^g 72 5° S5 60+ gg 60+ msg l4g 43 100 40 290 50 142 47 87 34 55 31 ms43 SO 32 25s 49 25s 45 S3 29 95 47 S3 43 yg3 44- g 3g 53 82 55 38 55 3g 60+ vl9 g2 52 gg 5g gg 51 87 19 288 These tests, though mostly quite incLd.eqU t 9i .tv ee , o cf tr eo n se u ga gn ed o perhaps two linkages (R w ea ls a to ib vt ea li yn ^e ld i tf tr lo em st eh ee d Florida plantings m la at se tr i sa pl r inis g ; av aa di el qa ub al te e for tests next summe l ri .n )k ag Se u go gf e sm ts i4 o3 n w oi tt h either sr or an i n si f pi rc oa bn ac be l yb e oc fa u ns oe so if g the great deficiency i on fs t ma sn uc 3e ia nn d t ho ef oa nn e in the other. There i n w et rh ee ft ee ws t x gw 3i t Ph l as nr t. e It seems likely that w vi lt 9h mb am y2 . b e T lh ie n kF e? d distribution was 42-25-21-0. l4. Differential dominance in number O ne o f o kf ert nh ee l F- ri o' ws s .u s -e d by Dr. Wiggans in the p d ro ou db ul ce-cross 29~3 tion of a cr08S of a ( 1O 2n -o rn od wa g ia n bW rh ei dt e l) i nw ei th an 8-row line 41 T (h Le u cF e t sp l Fa an vt os r is th e)o .w a high percentage o C fr o 8s -s r oB wa n et aa rm s, . on g ot lh de e no ther hand, has a co a ng se i do ef r a1 o2 l- er o pw e re ca er ns t, - though also a cross of ( P au r 1d 2u -e r o3 w9 ) liw ni et h an g-row line (Purdu d ei f 5f 1e ;r .e nc Te h is su g sg te rs it ke id n ga comparison of Fi'sf t rw oo m g c- rr oo sw s el si ne os f , t1 h e and 51 » noted above, in wc il tu hd i tn eg n 2 1 2a n rd o w3 9 l in neo st ,e d above. The res t ue ls tt s a or fe og ni ev e sn e ai sn o ns u sm mary form in the acco s mt pa at ne ym ie nn gt tw ah bi uc lh a rs hows the mean number o o ff kc er ro ns es le s r ob we st w ie ne n g—row and 12—row inbred lines. Inbred lines F-, crosses with Line 1 llnc-51 Differ- Mean Mean Mean ence in Designa- Number number Number number Number number number tion plants rows plants rows plants rows rows.. 1 57 7.S4 Jjl gg .. 7 ..25- 2 49 12.64 82 g . 7 6 gg 1 0 . 3 4 1 . 5 8 3 59 12.27 92 9.07 86 1 0 .5s 1.51 63 12.3S 86 9.16 80 9 . 9 5 •79 39 95 1 2 . 0 2 71 9.77 90 n . 3 6 1.59 1 1 59 12.34 56 9.57 86 9 . 9 3 .36 ill 69 1 1.go 75 9 .2S V 9 . 5 3 .25VI 50 12.04 60 g.90 54 9 .S9 •99 VII 107 1 2 . 2 8 12 0 9.15 91 1 0 . 1 3 .96 B 97 1 2 . 1 0 85 9.04 73 10.4l 1.37 G 74 1 2 . 1 1 93 9-05 37 1 0 . 0 5 1 . 0 0 Average 1 2-row and Fn lines 1 2 . l4 9.18 1 0 . 2 1 1 . 0 3 In every case the F^ row 5 1 number w wh ae sr e hil gi hn ee r ( 0.w 2a 5s tt oh e 1.g 5- 9r )o w parent than an wd he rt ehe la iv ne er 1a g we a s di usf ef de ;r ence was one kernel Fi rol wo .t s, Oft he t hel ow te ws et n tyr ow number was in a tnd 5 h1 e t ch re o sh si g oh fe s 1t wi in t h 2 with 39- The frequenc t yh _e d if so tu rr i but il oo nF \ ts o f from crosses of these four lines are as f ollows: 289 Inbred lines Frequency distribution for row number $-row 12-row g 10 _12_ 14 Total Mean 1 2 51 31 $2 g.76 1 39 16 47 g 71 9.77 51 2 l4 45 29 gg 10.34- >51 39 1 29 2 90 11.36 Not only do the two £-row lines differ, #1 tending more strongly than #51 to give low row number in Fp, but #39 tends more strongly to give high row number than does #2. 15. Heterosis of number of kernel rows. - In every one of the crosses of the Tfl 3— row line with the ten 12—row lines, the average row—number of the two parent lines is greater than that of the corresponding F^. Of the ten F^'s involving the same 12-row lines with #-row line 5 1 , four have mean row- numbers greater than, four less than, and. two equal to thê average of the two parental lines. It is perhaps notev/orthy that the Fi mean of the 1-2 cross differs from the parental average by —l.£> rows, of the 1—39 cross by -0.16, of the ;.l—2 cross by +0.35> and of the 5 — 39 cross oy +1»3&» it the last of these crosses alone had been under observation the result might well have been termed heterosis - and perhaps correctly so.' There is certainly nothing in the general averages to suggest heterosis of row-number. The average of all F^'s involving line 1 is less than the average of parental means by 0.31 rows and of those involving line 51 greater than the parental averages by one 0.17 rows. Records ™ere also obtained last season from F]_ cultures whose parental lines had approximately equal numbers of kernel-rows. The data are given in the accompanying table showing the mean number of kernel rows of inbred lines and their F]_ progenies. Inbred lines F-j progenies Mean Mean Designa- number Average number Differences tion rows rows 1 7.34) 7. 7.90 39 .5 10 0. 51 ) 20 2 12.04) 4 12.3Si 12.21 12.41 0.20 2 12.04) II 12.34) 12.19 12.61 0.42 2 12.04) 12.02) 123 .9 03 12.37 0.34 12.02) 3 t 1 12 2, .3 23 0) 12.5s 0.3S 290 39 12 .0 2) 11 1 [ 2 .3 ^ : 1 2 . 1 8 13.19 1 . 0 1 11 1 2 . 3g it 1 2 . 3 s :r 12.36 1 2 . 5 3 0 . 2 0 Individually, most of these differences in number of kernel rows are not statistically significant^ They are, however, all positive and, as a whole, are definitely sig- nificant. In general it appears, therefore, that some, though slight, heterosis is shown in number of kernel rows. 16. Influence of soil fertility on kernel-row number. S ome years ago two 12-row inbred lines ̂ and the F-l cross we g rr eo wn on sand of extremely poor fertility and on very ricn soil. The test was carried on during two seasons and^the number of plants involved were 281 on rich soil and 2c~J p ono or. The row-number means are compared in the following table: Rich Poor Differ- soil soil ence Inbred A 12.6 1 1 .1 1.5 Inbred B 12.3 10.6 1.7 F1 A-B 12.5- 11.5 CLs_2 All 12.4- 11 .1 1.3 The effect of extreme differences in soil fertility on number of kernel rows is obviously greater than that show a ns heterosis. Neither effect is sufficient seriously to mask genetic differences in studies of kernel—row numbers, R. A. Emerson 17. Brittle stalk-2 (bk2). Plant appears normal, t bh ue t leaves, stalk, ear, and all parts break easily unde p rr essure. Viability good. Classification good at all stages of development by bending the leaves sharply. The seed was originally received by the Maize Genetics Cooperation from L. C. Raymond, of Quebec. A test for allelism with bk was negative (News Letter, March 23, p 1. 9 371 ,) . Brittle stalk-x (bk-x) reported by Tiggans (News Letter, March 6, 1 9 3 8 , p. 12) proved to be an allele of bk2 (News Letter, April 15, 1939, P» 12). Bk2 is linked with sh and wx in chromosome 9 as shown by the following F^ data: 291 F1 genotype Fr 2 progenies sh wx + 29 sh wx bk2 1 sh wx + . opifed + + bk2 37 + + -1-+ + bk2 seilea 95sh + bk2 3 sn + + 11 + wx + 28 + wx bk2 0 Total = 20^ sh - WX = 22/o wx - bk2 = 15?* sh - bk2 18. Chromosome 9. - Linkage of gb and wx: Genes Linkage Phase G -̂ Wx g4 wx ĝ- Wx gH- wx Total % Recomb._ Gk Wx cs 379 ^ 11 32 ^26 5 19. Vestigial glume (Vg) and Tunicate (Tu). The two dominant genes Vg (Sprague, 1939) an(T Tu (Collins, 1 o 9p 1p 7o )s i ht ae v e effects on the length of the glumes in Doth t s ht ea minate and pistillate inflorescences of maize. /estigial glume, as the name implies, exposes the anthers and remov m eo ss t of the glumes from the ear5 whereas Tunicate incloses t he anthers in long glumes and the individual kernel h su s ik n- like structures. In view of these differences, would p al ant with the genetic constitution Vg_Tu he like Vg? or Th? or neither of them? In the progeny of a cross of Vg/vg x Tu/tu four types of plants were observed: Phenotype (length of glumes) Probable Staminate Inflorescence Pistillate Inflorescence Genotype Vestigial Long like Tu, but more Vg vg Tu tu narrow Vestigial Vestigial Vg vg tu tu Tunicate Tunicate vg vg Tu tu Normal Normal vg vg tu tu Since ordinarily the length of the glumes in the tassel i d s irectly correlated with the length of those on the ear, i is t difficult to explain why, in plants with the genetic con s -titution Vg vg Tu tu, Vg shows epistasis to Tu in the tass a eln d not on the ear. It has been noted, however, that s t oi mm ee s plants heterozygous for Tu do not have exceptionally long glumes in the tassel. Perhaps there is an upper lim t io t the length of glume that Vg is able to reduce to a mini tu ar -e size. ̂ Further tests should be made to note the appear a -nce of plants with the genetic constitutions Vg Vg Tu _Tu, Ve.: Vg Tu tu, and Vg vg Tu Tu. This material would not b e ea sy to obtain as plants homozygous for Tu are usually ma a ln ed female sterile. Likewise, Vg Vg plants are difficu p lr t od tu oc e as Vg vg must be grown under very favorable green- house conditions to obtain viable pollen. D. G. Lamgham, Estacion Experimental, El Valle, D. F. Venezuela 292 Cornell University and Division of Cereal Crops and. Diseases 1, In an Fp population of perennial teos f ir no tm e s oe be td ab ir neo du ght from the original station in a Mb ee xr ir ca on ,t ai nn dividual appeared in which the meioti b ce h ca hv ri oo mr o sw oa ms e similar to Beadle's "asynaptic. 1 e os ys ne an pt si ia sl l wy a sn ormal up to early diakinesis. Therea d fe ts ey rn apsis caused an almost complete disappear q au na cd er iv oa f lents and bivalents at metaphase. The r sa cn ag te tme en rt e d o af r-univalents in the meta—anaphase stage r e ss te rm ib kl ie nd g li yn compatible hybrid chromosome beh m au vt ia on rt . is Thh ei ghly cross- and self-sterile although th w ea s poa lp lp er no ximately 35$ well filled. Fortu m na ai tn et la yi ,n e id t e ca as ni l by e for further tests by vegetative propagation. L. F. Randolph and Harold E. Fischer 2, Attempts to produce true breeding, f er ht ii gl he l y an sd el fh ighly self-sterile lines of tetra i pn lb ore ie dd i mn ag i zea nd o y selection thus far have not been v f eu rl y. suL ci cn ee ss s -inbred 5-8 years continue to segregat in eg fd oe rg r ve ae rs y -of self-fertility. However, relati l ve ev lel ys hio gf h fertility can be maintained by selectin f ge r tt hi el e m oe sa tr s in each generation, and self-sterile ears t t eo n dp roduce mostly self-sterile progeny. 3. Haploid frequencies reported in the Ne M wa sr c Lh e, t t1 e9 r3 8 o, f from untreated and X-rayed pollen 15 0 i, n0 v0 o0 l vis ne ge dling counts indicated that X-raying m a tt he er i pa ol ll ly e ni ncreased haploid frequencies in maize. the Sn i na cd ed itional counts have been made and the th ni us m bet ri sm e ata re sufficiently large to warrant a comp o an rl iy s oo nf nf or te quencies from X-rayed and untreate a dl s po o llf er ne ,q ue bun tc ies in different stocks. These sto a cn k s in xb nr ce ld u dl ei dn e, designated A in the table\ a 3“way i n hv yo bl rv ii dn g this same inbred line as one of th p ea r 3e n it ns b r( e3 d) ; a commercial strain of Golden Banta ( jC n) ; s wa e eg te n ce ot ri nc a-tester stock (D)j and a group o e fo u ms i ss ct eo lc lk as n -(E), no one of which was large ni ef ni oc uga hn t foc ro mp sa ir gi -son. Haploid frequencies per th i on u st ah ne d s pe lv ae nr ta sl stocks from untreated and from X-rayed p (1 oH00 lle nr) are given in the following table: Number of plants Frequency per 1000 Stock untreated X-rayed untreated X-rayed Difference 2N N 2N N A 23,230 24 12, 16 1.03 1.26 O .23 B 21 7, 10 510 13 7,280 7 .62 .96 .34 C 5 1 ,^ 5 27 30,735 27 .52 .88 .36 D 53,^27 6 26,04-5 .11 .24 E 21,9 9 22 .3520 7,480 10 .91 1.33 .42 Total 17 1, ^ 90 gi!,255 69 Mean 0.64- 0.96 0.32 293 There was a consistent increase in h ta hp el o fi rd es q ua em no cn yg ot f he X-ray progenies, the aver i an gr e 5 i0 n cp re er a sc ee n bt e. - The dosage used (1500 v i re )l d d eo cf r ev ai sa eb dl e t hs ee ed approximately 50 r i Pa el rl y c ei nn tc r ae na ds e ad l st oh e m ad ti ef -ficulty of making If co ld ad ss s ifof i ca1+ t0 i: o1 n sb .e taken to indicate s s ii gg nn ii ff ii cc aa nn ct e ,d i tf hf ee r le en ac se t in frequency of hap b le ot iw de se n p eu rn t tr he oa ut se ad n da nd X-rayed pollen i O n. i ag n. y oT nh ee ^ sl te oa cs kt id sifference observed (st o od cd ks Ao ) f i6 s6 : 01 . da 5g a wi in ts ht such a difference o bf e ir na gn d do um e s ta om p el ri rn og r. s By the same criter n ii of ni ,c a tn ht e d li ef af se tr e sn ic ge for the five stocks whi tt oaf gl ev' t hth ee r o ib s se 0r .v 1e 1,d mean difference is a 0r .e 3 2m .a ny T ht eh o ou ds da sn d hs e rt eo one against so consistent a difxere b ne ci en g due to chance alone. A similar comparison of the diflerent s t so tc ok c kA s i ss hon wo st ts hi ag tn ificantly different n fo rt o md i sf tf oe cr ke n Et , f ar no dm BC . Stock C, and possi s bi lg yn i sf ti oc ca kn t Bl ,y df ir fo fm e rs st ock A, and stock D o dt ih fe fr es r. s fr(S oe me aa ll ls o t hS et abler, this News p Le ec tt te ed r ;t .h at I tt h we a sh a ep xl -oid frequency in i h ny bb rr ei dd s l iw no eu sl d a nb de tr he el ia rt ively high, due to in tg h e in eb lr ie me id ni an tg i oo nf dd ue r leterious genes which th e m ih ga hp tl o bi ed ls et ta ht ae l; mbu t there is no obvious t h ee x pe lx at nr ae tm ie ol ny ol fo w frequency noted in Th te h e ha ap -l to ei sd ts e r wh si tc oh c k di (d D) .a ppear in this sto o cn k t wh ee r ea v ae sr a vg ie g oa rs o ut sh ose in the other st t oi co kn s o wf i tt hh e t hi en b er xe cd e pl -ine and the 3~way h w ye br re i du n wi hf oo sr em l hy a pm lo or ie d s vigorous than those of the other stocks. The identification of the haploids was o f m ar de ec e ws is ti hv e the en d ao is dp erm and seedling gene t si ,o n si tn o math te e s ee xe ad ml ii nn ag - stage, and final v t ei rp i fc ih cr ao tm io os no m we i tc ho u rn ot os t. The frequencies b te h usi nt oe br tp ar ie nt ee dd aa rs e m *i on imum frequencies, si t nh ca et ia tl l iso f u nt lh ie k eh la yp loids were identif h iy eb dr .i d O( np lr ye s su em ea db sl y wit tr ni ploid) endosperms s wt eu rd ey . i ncA ll ul d eo df it nh e t nh e aploids obtained wer p ea t me ar tn ea rl n ah la sp , lo ai ld ts h ouw ge nre looked for in s w oh mi ec h o t in tv no el v ce rd o se sa es si ly recognizable recessive see t de lr is n gc o cn ht ar ri ab cu -ted by the pollen parent. L. F. Randolph Duke University. Durham, North Carolina Lg3 is not an allele of lg2. This h th ae s p br ee es ne n sc he o wnof bn yo rmal plants in backcro c sr sos s a nol .g 2 F p x fL rg o3 m. theT he following three-poin t th a dt a tL ag 3 i nT di ie cs a ta eb out two points to the l li en fk ta g oe f m Ra gp . fo (r T hc eh romosome 3 should have an cd r a a^ ta t t het he l er fi tg h et n. d The Linkage Summary was in error R .. A. E.) 294 Fp genotype 0 1 2 1.2 Total + Lg3 + ^S3 136 159 10 11 5 1+ ds + Rg 92^ 291 21 9 12^5 23. ̂ 1.7 # 0.7# H. S. Perry Iowa State College, Ames, Iowa 1* Three point test on chromosome 1, involving a new dominant tassel-seed, _Ts6, originating from a 'freak ear* in the Iowa Corn Show about 9 years ago: F^ genotype 0 1 2 U 2 Total + + Ts6 93 S3 9^ 59 1 1 0 1 br bm2 + 176 ,153. 2 1 3321+6.1# 0.6fo 0.3 fo Ts6 is recommended as a first class, useful marker exhibit Ing sharp segregation and producing good normal ears 'rows characteristically irregular) when tassel is pulled early. 2. Two point tests on chromosome 1, Genes Phase xy xY Total fo Re comb. Ts6 F CB 21 17 20 32 90 k l . l Ts6 Gs CB 126 37 46 113 32^ 25.6 Order of genes in chromosome 1 would then be: br f ge bm2 Ts6. (See also Emerson, this News Letter) 3. Natural mutation of Y gene from Yy to yy in one kernel among 12 crossed ears (totaling over 7200 kernels). Female parent in crosses was a standard long-time inbred yellow dent line; male parent a white, Hickory King inbred. E. W. Lindstrom Iowa State College and Division of Cereal Crops and Diseases, U.S.D.A, 4. The first group of F2 data, below, suggests that g2 is on chromosome 7* Mumm's soft starch character, hh, car- ries an inhibitor for japonica. Neither bm3 nor vl3 show close linkage with j_. Genes Phase XY Xy xY xy Total & Recomb. G2 Lg RS 353 102 116 4o 611 ^7 G2 Wx RS 371 109 96 33 611 4S G2 Rg CB 75 69 62 74 2S0 ^7 G2 IJ RS 310 11s 101 3 532 20 Ed G2 RS 221 9^ 89 13 417 J Bm3 RS 216 Si 65 13 P377 41 J V13 RS 1685 7^ 36 12 292 ^5 G. F. Sprague 295 University of Minnesota, St, Paul, Minnesota 1. I have tested yellow green-3 c wh ir to hm o as o tm re i s0 o, m ia cn d f oh ra ve found evidence that vg3 is not t ih na t chromosome. 2. The glA which was reported by w i Dt rh . w Hx; a yei ss tg oe n be et i lc ia nl kl ey d different from t i hs e c ona el li tn hg a t gl So prs as gy u- e1!- , as shown by an in t tw eo r. c roS si sn c oe e tt wh ee e nl i tn hk ea ge relations of t I h is su g og ne es t a rt eh a kt n ot wh ni ,s ino n ye be called £14- an g di v te hn e "a o nn e ew o fn u om pb re ar g; u e unless there are some reasons why this i n so t feasible. 3. I spent most of my time last s st uo mc mk es r, rs eo cm ue p eo rf a tw ih ni gc h m yh ad reached such an fi ac gu e lt ty h ati n 1 ge ht at di n dg i f-them to germinate. ex Ht or we em ve el ry , f wa ev o hr aa db l ae n season and in most ca g se et s ma I t we ar si a al b le es t ta ob lished. I used a few of the s tt ro ick ss o mif cr om the Coop, last year. i nt We hn is li ev el 1 y, d idi t n od ti d ,s *s ue ^em that certain of t c hh ee mc k ni en eg d et do ib ue r tc ne er rt ain that they are st l ii ln lk a sg ae t iw so fr ak c. t orO yn e f oo rf the difficulties p r se es ee mn sc e t oo f b e3 tt hy ep es which was mentioned by t Dh re . t Li am ne g hh ae m s ae tn t them to me. Howev o et rh , er o ns et o oc rk s t wa ol so s te ne em ed to have some othe T rh e d is ft fo ic ck u lo tf i eN so .. 5, for example, did u ns ou ta l s; eei mn tf oa c bt e hI a vw ea s a su nable to recognize any trisomic plants in the field. Burnham is not alone in having trouble I t w* is t ha tj ho eb tf ro ir s os mo im ce s .c ytogeneticist - which I am not. k .a .l . University of Missouri, Columbia , Miss D oi uv ri is i ao nn d of Cereal Crops and Diseases. U .3 . j »,A_. 1. Etched endosperm-virescent seedling. sy Tm hb io sl ce ht a, r aa cr to es re as a mutant in an X-r e an yd o ps rp oe gr em n ya ,n d a ns de e td hl ei ng effects are very c p ll oe st ee ll yy il fi n nk oe td . comT -he endosperm is sim s ic la ar rr e td o e sn od mo es pe or r ms t hep reviously reported m ba ur t ke id s a mn od re u s du ia sl tl iy n cp te lr ym its a good separ s ao tm ie ot ni ,m es p ir ee d su ec ee dd s i an r es ize but have good li vn ig a bit ly ip te y .i s a Tn h e ex sc ee el dl ent one, both f g oa rt i so hn a ra pn nd e sf so r oiv ia sb ei gl ri et -y. Data from a t g hi rv ee en - pobe il no tw , t esi tn ,d ic asa te the order of genes e t tot he b e ou lt ge 2 rm ao s et t , ge wn ie t n on the long arm of chromosome 3> 12 a ou on ui tt s beyond a. F]_ genotpye 0 1 2 1^2 Total + a et 126 135 6o 55 20 25 3 3 4-27 lg 2 + + 261 1 1 5 . 4-k 6 26.9$ 10 .5 $ l A1* 296 2, Notes on haploids. In seedling progenies grown from X-rayed pollen and ultraviolet treated pollen, a large num- ber of haploids was found. The frequency of haploids in the ultraviolet progenies was somewhat higher than in the X-ray progenies, though in both cases the frequency was not very greatly increased over the control. An interesting feature was a distinct tendency for haploids to occur more frequently in progenies of certain female parents than of others, in fact, the untreated female parent had a greater influence on the haploid frequency than the treated male parent. This suggests that the factor limiting haploids may be their in- ability to survive to the seedling stage, and that a consid- erable number of haploids may be included among the r,germless seeds'* resulting from the use of irradiated pollen. (See also Randolph, this News Letter) Fifty-five haploids were transplanted to the field and grown to maturity. They showed rather surprising fertility. Forty-one of them produced silks, several from two ears, and all of the ears were pollinated. Twenty-seven of the forty- one plants set seed, and ten of these yielded ten or more seeds per plant. The highest numbers of seeds harvested per plant were 97, ^7, and ^3 respectively, in each case from a two-eared plant." _ L. J. Stadler North Carolina Experiment Station, Raleigh, N ... C. 1* Last spring a total of 1203 first generation selfed ears were examined for deficient kern 4 els. Out of this lot S - ears were found which appeared to be segregating for de- ficient kernels. This means that on the average 6.9870 of all plants selfed in the eighteen Southern varieties were heterozygous for some deficient kernel character. Chi-square applied to these data proved definitely that these varieties do not have the same gene frequency for deficient kernels. Indian Chief has significantly fewer heterozygous plants (0.7$), Mathewson’s Golden Prolific and Woodfs Golden Pro- lific approached significance in having fewer than average heterozygous plants. Golden ^ueen ( 1 20 0.5 0%) and Biggs1 Two par ( . $) have significantly more heterozygous plants than the average of all varieties. 2. In an inbred strain of Yellow 8 Horsetooth two selfed ear were found to be segregating for rootless. Jenkins pointed out this character last June in our breeding field. The rootless segregates have all the characteristics ot plants of rt rt type (Jenkins, 1930; 1 C9 o3 r5 nell Memoir ISO, p. 20, ). If crosses with rt stock prove it to be the same mutant it will be the second occurrence of this distinct root mutation. Our strain has never been grown in close proximity to any rt stock, Paul H. Harvey 297 Agricultural and Mechanical College of Texas. College Sta- tion, Texas 1, Further studies on chromosome knobs of S v oa ur ti he t Ai me es r ih ca av ne shown that the majority of Pe vr au r ieB to il ei sv i fa r, o m and Ecuador have knobless chrom s ou sp op mo er st .s ou Tr h isp revious suggestion that the An w dh ei ac nh rw ee g ir oe ng ,a rd as the primary center of dom m ea si tz ie c, a ti is o nt h oe f only region where pure rn l aa ir zg ee hl ay s r ne op tl a bc ee ed n by Tripsacum-infected varieti i es s .t rue I f mo ts ht is of the stocks of North Ameri w ch ai nc h m ait zhe e m wa ij to hr ity of genetic and cytologic c ao ln du sc tt ue did e sa re a rp e robably polyploid for certain re c gh ir oo nm sa t Oi in . t heT his may account for the m fi an cu tt e t hd ae tf i sc oi me en c vi ee ^s are quite deleterious while other de lf ai rc foi ee rn cies have no appreciable effect. 2. There seems to be a possibility that a t wy ipe l d of o r ma fi ez re al is still in existence in Paragua c yo .l lec A to br o tai nn i cP aa lr aguay with whom we have be en ec ne ih na s c os re rn et s pu os n da - specimen of a maize plant t o w hh ia cv he hf eo u cn ld a ig mr so wing in a colony in a clea e rs it ns g m ii nl e ts h ea w la oy r from human habitation. The s sm pa el cl i ma en nd we aa sr less but bore at the base o t fa s ts he el , u np bi rs at ni cl hl ea dt e spikelets enclosed in glu f mr eo sm . an Iy t s dt iu xn ft ee red c lc orn which we have previou t she l y st sa em ei nn a mte ha an vd i ngp istillate portions of the di is nt fi ln oc rt el sy c ens cep ea rated. Seed of this pecu y le it a rb e te yn p eo b ht aa si n ne od t but seed from a variety_cul q tu ia vr aa tn ey d bI yn di ta hen s in the same general local p il ta yn t gs a vew it rh i sek no tb ol ess chromosomes. This is t o hf e m -a ii rz se t w vi at rh x ek n yo bless chromosomes which f wr e om h avt ehe rl eo cw el ia vn ed ds of South America. We shou t lh de , b oa fs i cs o uo rf seo ,u r o n hypothesis expect wild maize to have knob less chromosomes. 3. Additional linkage studies in t e co rs oi sn st ee s w oi ft h F lv oa rr ii do au s genetic stocks show that s eg tm re an nt ss l ocA a ta in od n C are located at opposite J ej. ndsas oi f nd ci hc ra ot me od s ob my e our previous data. Both sh s ou w an ld in kgl a3 g. e wiS te hg ment B is located on chro f ma oi sor ml ey c 1 lo ss he o wl ii nn g kage with P and a slight a ig ne d iw ci at th i ob n m O2 x. lS ie ng km -ent D appears to be located on chrom 9 o sa on md e shows linkage with wx. k. When Chaleo and New teosinte are cro h sy sb er di d t hh ea s F pp aired pistillate spikelets although both pa h ra ev ne t su npaired spikelets. Florida, Durango, Nobogame, and New teos c ir no ts es ed h avw ei th b eea nu niform inbred strain and the c r Fo ps s he yd b rt io d t bh ae c ks -a me strain to obtain popula a tl il ont sh e ing en we ht ii cc h variation is due to segreg f aro tm i ont eo os fi n gt ee n. e s These populations show that the major part 298 of the segregation is due to the four block t sr a on fs l go ec na et si o on r segments which we assume t o h f ar vo em bT er ei np sa dc eu rm i. v ed Durango has the same lour s F el go mr ei nd ta s, fb ou ut n dt h mey have less effect which sug m ga ev s tb se ts hm aa tl le tr h eya nd contain fewer Tripsacum t ge eo ns ei sn .t e Nc oo bn ot ga ai mn es only three of the four s F el go mr ei nd ta s a fn od u nD du r ia nn go teosinte. The New teos n io nt t ey e ht y bb re ie dn s c hl aa vs es ified. All of the data su t pi po on r tt h oa ut r t ah se s uG mu pa -temalan teosintes represent p ro thd eu c pt rs i mo af r yt he hybridization of Zea and Tr t ih pe s aM ce ux mi ,c a wn h it le eo sinte are secondary or tertiary products. P. C. Mangelsdorf and R. G. Reeves III. MAIZE PUBLICATIONS Maize publications that have appeared s N ie nw cs e L te ht et e 1r 93wa v s issued together with a few earlier papers are listed below. Abbe, L. B. - The histological background for dwarfism in Zea mays. Amer. Phil. Soc. Proc. 76: 7^3-7^7• 1936. Anderson, E. G. - Translocations in maize involving chromo s ome 8. Genetics 3&5-390. 1939* Akemine, T. - Chromosome behavior in the intergeneric hy T br ri ip ds of saceae. Japan Jour. Genetics 14: 66-73♦ 1976 * Aleksandrov, V. G. and Iakovlev, M. S. - Die m k oo rr pu hs o lu on gd i ed e dr e sb au des endosperms bei verscni f eo dr em ne en n von Zea mays L. (Russian with German summary J )o .u r. Bot. U.R.S.S. 20: 2^5-281. 1933* Arnason, T. J. - Cytogenetics of hybrids between a Zn ed § E mu âch rsl aena mexioana. Genetics 21: 40-oC. 193°* Beadle, G. W. - Chromosome aberration and gene s t mi uc tk ay t ic oh nr o im no some plants of Zea mays. In Cytologia F ,u jii Jubil. Vol. Tokyo, p p . 43-56. 1937. _____________ - Teosinte and the origin of maize. Jour. Hered. 30: 2^5-2^7* 1939. Blaringhem, L. - Sur une variete nouvelle, a g a rc aa ij no su , d ed u t eZ ie na t om ays forme polysperma. Compt. Rend. Acad. Sci . Paris 203": 1^77” 14ol. 193r» - Origines et destinee du mais a m gu rl at ii np el se s (Zea mays var. polysperma). Con a t rl i' bh ue tr ie od ni te des caracteres acquis. Ann. Sci. Nat. X, Bot. 19: 33-^2. 1937- Brink, R. A. - Heritable characters in maize. XLIX m .i dri Pb a. l e Jour. Hered. 26: 214-9-251. 1939* 299 Burnham, C. R. and Cartledge, J. b e Lt .w e -e n L is nm ku at g er e :sistance and semisterility m maiz J eo .ur. Amer. Soc. Agron. J l : 921+-933* 1939* Capinpin, J. M. - A lethal-linked kernel variation c oo fr n. L agkP ih ti lipp. Agr. 27: 866-874-. 1939- Collins, G. N. and Longley, A. E. - A tetraplo m ia di z he y ba rn id d p oe fr ennial teosinte. Jour* Agr. 123 5-133. 1935• Collins, G. N. and Maxwell, L. R s . ee -d l Di ®n lg as y ®w ^i t ^h ^ X i- ir na gy 1s °. £ gmS ac li ze en ce 83: 375 37°. if3 • Coocer D. C. - Macrosporogenesis and embryo- i sn a cE uc dh evl ea le on pa m em ne tx icana and Zea mays. Jour. Agr. Res. 55: 539-551- 1937- Cooner D. C. and Brink, R. A. - Chromo P s oo mf e m ha oi mz oe l of gr yo m i nd i rf af ce er se nt geographical regions. Amer. Nat. 7 1: 582-587• 1937- Dawson, C. D. R. - An exa a mp pp ll ei e od f t to h ea corn breeding experimen .t. Annl. Eugen. y . 157-173. 1939. TTrrwvronn R A - A zymotic lethal in ch a rn od m oi st os m el i 1n k oa fg e m aw ii zt eh neighboring genes. Genetics 2 : 36g-3^. 1939. Fraser A. C. - Some materials for genetic instruction J .our* Heredity 30c 375~37&» ^939« Groner, W. G. - Respiration of green and chlor c oi pe hn yt l lt y dp ee fs i -of maize, Amer. Jour. Bot. 23. 3S1 3 3* 1936. Hadiinov, M. I. - A dominant mutable ge i nn e t fh oe r R p us re pr li ee s c oo lf o um ru ltiple allelomorphs C io nm p Mt a. i zR ee .nd. (Doklady) Acad. Soi. U.R.S.S. 23: 36° 39- 1939. Holbert J. R., Flint, W. P., Bigger G ,. JH .. H- . ,R e as ni ds t Da un nc ge a na ,nd susceptibility to O a se cc oo rn nd sb tr ro ao id n s chinch bugs. Iowa State College Jour. Sci. 9: 199-212. 1935* Janaki Animal, E. K. - A Saccharum-Zea cross. Nature 142: 618-619. 1938. Tenkins Merle T. - The effect of i w ni bt rh ei en d ii nn gb r ae nd d l oi fn e ss e lo ef c tm iaize upon o n the hybr s iu dc sc e ms as di ev e a fg te en re rations of selfing. Iowa State Colleg J eour. Sci. 9 : 215-236. 1935* 300 Jenkins, Merle T. - Crop improvement. U.S. Dept. Agr. Year book 1936: 455-522. 1936. - New developments that may^affect the corn " in^ustrlesT'- The importance of corn hybrids to i tn hd eu s ct or ry n. Contr. Iowa Corn Res. Inst. 1: r_0o 212. i j j y * - The segregation of genes affecting yield of grain in maize. Jour. Amer. Soc. Agron. 32. 19 55^0 ~ 3» . Jones, D. F. - Somatic segregation due to hemizyg m oi us ss i an ng d ge ^nes and its bearing on the problems of atypical g rowth. Proc, Nat. Acad. Sci. 21: 90— 96• l-/35* - Segregation of color and growth regulating^ g ̂enesTn somatic tissue of maize. Proc. Nat. Acad. Sci 22: 163-166. 1936. - Sex interp;rades in dioecious maize. Amer. Jour. Bot. 26: 412-415. 1939- - Continued inbreeding in maize. Genetics 24-. '452^473. 1939. Jones, D. F. and Singleton, W. R. - The improvement of nat- urally cross-pollinated plants by selection in self- fertilized lines. II. The testing and utilization of inbred strains of corn. Conn. Agr. Exp. Sta. Bull. 376: 633-691. 1933* Johnson, I. J. and Hayes, H. K. - The combining ability of inbred lines of Golden Bantam sweet corn. Jour. Amer. Soc. Agron. 2$: 246-252. 1936. Kempton, J. H. — Modification of a Mendelian ratio in maize by pollen treatments. Jour. Agr. Res. 52: 01-121. 1936. and Popenoe, W. - Teosinte in Guatemala. Report* of an expedition to Guatemala, El Salva C dh oi ra ,p as a. n d Mexico. Carnegie Inst. Washington Publ.,48., 199-210. 1937. Khadzhinov, M. I. - New cases of ligulelessness in Bu ml al i. z e.Appl. Bot., Gen., and PI. Breed. Ser. Ix. ( : 209- 275. 1937. - Genes of rough sheath in maize. Bul A lp .p l. B o t . G e n . , and PI. Breed. Ser. II. 7• 247-258. 1937. - Genes of glossy seedlings in maize.t Bu “ lA lp .p l. Bot.,"Gen., and PI. Breed. Ser. II. 7! 227-246. 1937. 301 Khadzliinov, M. I. — A new character tn maize 5 ramosasilkless structure of inflorescence. Bull. Appl. Bot., Gen., and PI. Breed. 8er. II. 7 • 259-267. 1937 - Koehler, B. - Crazy top of corn. Phytopath. 29: $17-^20. 1939- Langham, D. 0. - The inheritance of intergeneric differences in Zea-Euchlaena hybrids. Genetics 2p: ZZ-IO/. 1940. Lindstrom, E* W. — Genetic experiments on hybrid vigor in maize. Arner. Nat. 69: 3H-322. 1935- ___________ - Some new mutants in maize. Iowa State College. Jour. Sci. 9* 237-245. 193k* Longley, A. E. — Chromosomes of maize from North American Indians. Jour. Agr. Res. 56: 177-195* 193&* - Knob positions on corn chromosomes. Jour. Agr7”ResT 59: 4-75-^90. 1939* Mangelsdorf, P. C. and Reeves, R. G. - A trigeneric hybrid o f Zea, Tripsacum, and Euchlaena. Jour, heredity 26: 129~l40. 1935- Mangelsdorf, P. C. - The origin of Indian corn and its rela- fives. Texas Agr. Exp. Sta. Bull. 574, 315 PP- 1939- Marino, Antonio E. - Una variacion tardia en maiz. Instituto experimental ae investigacion y fomento agricola- ganadero Pub. Tecnica 15: 237-240. 1939- (Reprint from Revista Argentina Agronomia 6: 237-240). Martin, John H. and Rershey, Arthur L. - The ontogeny of the m aize plant - the early differentiation of stem and root structures and their morphological relationships. Iowa State College Jour. Sci. 9 ' 275-289. 1935* Martinez del Rio, P. - La domesticacion del maizy el problema d e la antiquedad del hombre en America, Univ. Habana 22: 3&-4S. 1939. Mather, K. - Competition for chiasmata in diploid and trisomic maize. Chromosoma 1: 119-129* 1939* McClintock, Barbara - The behavior in successive nuclear divisions of a chromosome broken at meiosis. Proc. Nat. Acad. Sci. 25: -̂05“4l6. 1939* Middendorf, F. G, - Cytology of dormancy in Phaseolus and Zea. Bot. Gaz. 100: 485-499. 1939- 302 Olson, P. J. - Exchange of certain alternative stable c a hac rters in crosses between dent and flint corn. N. Dax. Agr. Exp. Sta. Tech. Bull. 291, 3& PP- 1939. Overbeek, J. van. Lazy, an a-geotropic form of maize. Jour Heredity 27: 93-96* 1936. Paddick, M, E. and Sprague, K. B. - Maize seed characters in relation to hybrid vigor. Jour. Amer. Soc. Agron. 31* 7^3-750. 1939- Pardo Navarro, L. - Monografia sobre el maiz. Agricultura (Bogota) 11: 612-627* 1939* Powers, L. and Clark, A. - Failure of chromosome pairing as e vidence of secondary diploids in Zea mayp. Jour. Genetics 35: 301-313* 1937• Powers, Le Roy and Dahl, A. 0. - Failure of diakinesis m ae nt da phase pairing and the behavior during meiosxs of u nivalent chromosomes in Zea mays. Jour, Agr. -es. 6 • 655-66S. 1937. Psarev, G. M. - Physiological character of changes i i nn d um ca ei dze by removing male inflorescence. vTrans.title), Compt. Rend. (Doklady) Acad. Sci. U.R.S.S. 2r_: 1^9 193* 1939* Rhoades, V. H. - The location of a gene for disease res ist- ance in maize. Proc. Nat. Acad. Sci. 21: 243-246. 1935* Randolph, L. F. and Fischer, Harold E. - The occurrence o p farthenogenetic d,*i pl- oi* ds i* n tetraplo ̂id wm, aO in zn er\ Jg T U C t Nat. Acad. Sci. 25: 161-164. 1939. Russel, M. A. - Effects of X-rays on Zea mays. Plant Physi ology 12: 11 /-133 * 1937 * Shafer, J., Jr. - Physiology of lazy corn. 3ot. Jaz. 101: 6S-S0. 1939* Singleton, W. R. and Jones, D. F. - Early sweet corn hyb S rp ia dn sc ,r oss, Marcross, and Carmelcross. Conn. Agr. uxp. Sta. Circ. 13$. H PP* 1939* Sosa-Bourdouil, C. - Note biochimicjue sur l ’hybridc Ze x a E mu |c yh |l aena mexicana en premiere generation. Revue Bot. Appl. 15‘ 615-61?. 1935. Sosa-Bourdouil, C, and Miege, E. - ^Etudes des hydrides Z e ea n te rt e Euchlaena. I. Heredite du taux de 1 ‘azote ch Z ee za mays x Euchlaena mexicana. Bull. Biol. France et Belgique. 70: 35^370. 1936. 303 Sprague, G. F. - Hybrid, vigor and growth rates in a maize cross and its reciprocal. Jour. Agr. Res. 53: 2>19“$30» 1936. - An estimation of the number of top—crossed plants required for adequate representation of a corn variety. Jour. Amer. Soc. Agron. 31: 11-16. 1939* - Heritable characters in maize, 50, vestigial glumes. Jour. Heredity 30: 1^3-1^5. 1939* Stadler, L. J. - Loss mutations in maize. Iowa State College Jour. Sci. 9: 213* 1935* and Sprague, G. F. - Genetic effects of ultra- radiation in maize. Proc. Nat. Acad. Sci. 22: 571-591. 1936. ______ - Contrasts in the genetic ""effects of ultra-violet radiation and X-rays. Abstract. Science 2>5: 57> 1937* Uber, F. M. - Ultra-violet spectrophotometry of Zea mays pollen with quartz microscope. Amer. Jour. Bot. 26: 799-307. 1939. Weatherwax, P. - The phylogeny of Zea mays. Amer. Midi. Nat. 16: 1-71. 1935 - Yasui K. - Genetical studies in Zea mays. L. Bot. Mag. Tokyo ^9: 153-162, 23^— 246. 1935• 304 IV. INVENTORY OF COOPERATION STOCKS The following is a complete list of all^see i dn st th oe c kp o ns os we ssion of Maize Genetics Coopera o tn i ot nh .e e Ta nr es , l?i ^n e lm sa ny instances, give no in e dn io ct av t- ipe o n co on fc e tr hn ee d. In such cases, the record xa cm ari dn se d w ef ro er such information as they affo c ro dm .p ile Td h isa nd 1 .yt sh ̂e index made by Dr. Lebedeff. Tne symbol (x = ) selfed and # = sib crossed. 1931! crop Co 1 (x) y, segregating g3> 3 2 earsit (x) seg. dS, b ears i k (x seg. d5 , may seg. gl2 py, 6 few seedsn 7 (x) b es2 Is;, 7 earsii (x) y Ig gl2 vH- in various combinations, 2c> ear it s9 (x) and # seg. Y pg2 d, 6 ears I 10 (x) Y, g, may seg., pg d, 1 ear I 11 (x) y, seg. d2 lg, ( ears I 12 (x) seg. d2 lg Pr, 6 ears I 13 X and # seg. yt, 2 small ears It 14 (x) y a C R pr wx 'lg, 1 small ear I 15 (x) and # y a C R pr, seg. lg, 9 ears I 16 # a t u b cr lg in various combinations, 20 e I m a o r17 s s tly # a^ts1* sr lg in various combination 15 s, small ears I IS (x) I 19 (x) I 21 (x) It 2b # a na cr gl v5 Y , 2 small ears I 25 a na cr Y, seg. lg v5, 2 small ear I s 26 (x) sh cr ms3 pk in various combination seg. v and g, 8 ears I 27 U) Y seg. sp su Pr, 6 ears I 28 x) seg. Y sp su, ̂ ears I 29 (x) Y y + + / lo su, 5 ears I 30 (x) y lo + / + su, 9 ears I 31 # pr, seg. bm tn, 2 ears I 32 # pr, seg. bm tn, 3 ears I 33 (x) I 34 (x) I 35 X I 36 (x) I 37 # pr bv v2, 3 ears I 38 # A C R pr bm sh wx su, 6 ears I 40 (x) and I A a2 C R B PI Y, 7 ear: I b i (x seg. v3 Pr ys, 8 ears It )b} X bm bt, seg. pr, 2 small ears I b i xl I (xj I bbb6 (x! It b& (x! 305 bQ , lg, sk in various combin a al ts io o ns eg , . Pr A B PI Y, 50 ears » 119 (x) B lg v2 pr, seg. PI su, 6 ears " 120) " a1 (x) n2 d1 ) # A B lg v2, seg. Pr " 122) PI su, 40 ears " 12? # a Bb lg Y pi R c wx pr su, 3 ears " 124 # a i lg"B C rr pr Y pi, 9 ears » 125 # A cr C Rg pr su y pi b lg 1 j2 ,6 and 5 e» (x) # a a r sB PI C R Pr Y, 7 ears » 127 # a pr in Y C R, 7 e " 128 # a a rB s lg Pl Y c sh wx R Pr su, 1 smal a l p er a r " 129 in wx C R&, seg. su, 10 ears " 130 # A B lg y pl C Rg Pr Sex, 5 ear A s » 131 # C r 'Pt B PI Y cr, 2 small ears " 132 # A r £ c wx pr su P seg. sh, 3 ears " 133 $ a B PI C R Pr Y lg, 7 ears » 134 # A b pl C rr pv lg bm2, seg. su, 3u j, 9 ea " 135 # A R&* r y s pl b lg bm2 j, seg. C Pr 1 1 In su Ts2 v, ears » 136 (x) and # A c R^ „ g p ,r In Y pl b lg, brn2, 3, seg, su ts2, 12 ears " 137 (x) and # a C R pr in y 3 lg> 13 3 9 ears » (x) a P sh wx f, seg. su, lg, l ears ” 139 (x) a P sh wx su lg f , 5 ears w 140 # a B Pl lg v4 Y, 8 ears » i4i (x) and # ts4 lg B Pl in various coraoin., a a l sY o c sr e gn a, 20 ears " l42 (x) su pr ts*4 , seg. Y and white aleurone 6 ears1 !4x TJL , T ap 3 P, seg. Pl ana striped, 2 ears « l44 (x) Y bl, 3 ears » 145 x) Y seg. f12, su, gl, 9 ears 1 146 x) and ¥ Y f!2, seg. gl, 13 ears " 147 (x) and # y g!2, 5 ears " i48 (x) Y h, 8 ears " 149 (x) and # Y 0 A B Pl, 4 ear 1 s5 " 0 (x) y 02, 4 ears “ 151 (x) Fp of rs x A B Pl Kn, 3 ears » 152 (x) Pr, seg. v8 and d, 5 1 e5 a6 r s " 153- (x) seg. v8 su d and de, 10 ears " 157 (x) A c RS su, seg. Pr, may seg 1 .5 8 v 9, s le 4g . e aP r" r s x) su, may seg. v9, 9 ea » 161 x) Y r , s seg. v7 striped, 6 ears 307 Co 162 (x) seg. Y v6 or d, 10 ears " 163 (x) y, seg. vb d, 6 ears " 164 (x) may seg. v6, seg. striped, 2 ears 1 166 (x) y, seg. v7, 6 ears » 166 (x) and # Y, seg. sk, 5 ears » 167 (x) and # seg. sk, v 9 ears » 165 (x) and # Y, seg. sk d bl, ! ears " 169 (x) and # Y, seg. sk d bl, 12 ears " 170 (x) and # Y, seg. 6k, striped, 6 ears « 171 (x) seg bk v ts, 5 ears » 172 (x) Y seg. bd, 10 ears " 173 (x) ys x new y s, seg. Pr sh, 9 ears " 175 # bt2, seg. gl, 5 ears « 176-159, Stadler’s X-ray mutant 17 s6 » (x n 177 lxj ) seg. Y d wx v, 20 ears seg. A Rd j b lg 1 g7 ld, 10 earsu s (x) seg. d wx Pr R Y v, 10 ears » 179 (x) seg. A Rg rr Y wx yg, 12 ears 1^0 (x) pr j seg. A R6 r1* C Y wx new d, 6 ears n igi (x) pr, seg. A C Rs rr Y wx new d, n 11 15 2 e ars(x) seg. A R B lg j new fi, 15 it ea1 r5 s3 (x) seg. R Pr Y d wx glc, 15 ears » 154 (x) seg. Pr R Y wx gib, 12 ears « 155 (x) seg. A B j lg R d, new pg, 10 ears » 156 (x) seg. su j lg Y, new pg, 10 ears » 157 (x) seg. new pg, 7 ears it (x) aeg. A Rs rr Y wx su, new ar-like striping, 7 ears « 159 (x ) seg. A Rg rr Y su wx, new pg, 12 1 e9 a0 rs« (xj seg. w w2 w3, 5 ears n 191 (x) seg. w3 R 0, 19 2 2 ears«' (x) seg. w3 R C Pr, 6 ears » 19^ (x) seg. w2 R, few seeds « 194 (x) sei. w2 R Pr, 1 ear »' 197 (x) Pr T4-5, 10 ears « 195 (x) Y T5-9, 5 ears « 199 (x) Y T3-5, seg. su, 4 ears « 200 (x) y Ts-7b, seg. Pr, 1 10 ears 201 (x) Tl-10, seg. Y Pr, 11 ears « 1 1 202 (x) Tl-2, 9 ears 203-214, Inbreds for snrut resistance tests " 203 (xj Corne 2 l0 l4 11, 9 earsit (x) ,f inbred 2 10 05 years, 10 earsn (x) 1 inbred 11 years, 10 ears " 206 (x) Learning dent, 11 2 i0 n7 bred 5y ears, 5 ears (x) ” inbred 11 years, 10 ears " 205 (x) U.S. # 204 de 1 nt2 ,0 9 inbred 12 years, 3 ea rs ( x j Bloody Butcher, inbred 10 years, 12 ears n 210 (x) Oil Dent, inbred 5 years, 7 ears » 211 (x) West Branch dent, inbred 5 years, / ears n 212 (x) Silver Kin *1 g inbred 13 years, ( 1x 4 213 j earsOnondaga mite dent, inbred 11 years, 6 ears » 214 (xj Dutton’s flint, inbred 11 years, *+ ears ,r 215 (x) Y or, seg. pg2 lg wx, 7 ears 308 Go 216 (x) as ms17 zl pr, 9 ears it 217 (x) > may seg. brn v21 ys pr, 25 ears220) n ((xx))2 2 a1 nd # seg. A B PI Ig gl2 v) 4 ts, 6 ears 1935 crop Go 225 (x) gl3, also x gl6 and glc, 4 ears ti 226 (x) gl5, also x gl, gl^, gl̂ ,> S19? t 9i ears227 (x) gl6, also x gl2, gl3? g14> fJ-7 > S19 it > 13 ears223 (x) gl7, also x gl, gl3> , g!3> glc, glc, 17 1 229 (x) gl3, also x gl, gl3> gl^> gl-7 > g!9» glc, gib, seg. w wx, l4 ears it 231 (x) gllO, also x other gloss1 ies, seg. 3n si, 9 ears 23^ lg gl2 b v4 1 x gl5 > gl6, gH0, 3 ears 236 gl3 su x other gl1 ossies, 3 ears 237 gl3 su Tu tu x other1 glossies, 4 ears 239 lg gi4 # and x oth1 er glossies, 13 ears 242 gl6 ’# and x other glossies, 5 ears n 1 243 gl7 vl7 x other glossies, 5 ears 2 1 46 # gl6, 5 ears 243 glc (x) and x 1 other glossies, 4 ears 249 glc (x) 4 ears n 250 glc x 5 ears 1 251 gib (x) 5 ears it 252 gib (x) 6 ears it 253 gi1 b (x) 2 ears 255 # seg rs2 gl, 5 ears it 256 (x; seg Rs gl, 4 ears it 25S # seg, at v gl, may seg. bv, 6 ears n 259~260 # seg. bd, 12 ears t 261 u: cr3, very1 few seeds 1 262) bs (Hadjinov) similar to 2 77 b6 s7 ) (Woodworth), seg. v. ti 264 # seg. ba v, 2 ears ti 265 # seg.1 ba2 v, 3 ears 2 66 (x seg. variable bv, 6 ears it 267 # f b1 m2, seg. P v5, 5 ears 263 (x and # f b11 m2, seg. br, 6 ears 269--270 (x) and * seg. sr an bm2, few seeds it 11 2/1 (x bm2, seg. P, ^ ears 272 (x lg, seg. gs2 B v4, 3 ears ti 27 3 # A B lg 1 gl2 v4 pi, 1 ear 274 # A b pi lg gl2 v4, 6 ears " 275 * A b pi lg g2 v4, 2 ears " 276 # lg gl2 v4, seg. ts, 2 ears " 277 # lg gl2, seg. v4 ts, 4 ears « 27^-279 #' lg gl2, seg. v4 ts, 3 ears " 230 (x) sb and x testers, 3 ears 11 231 (x) ai 1 " }l , few seeds " 233 # Beg. yt, may seg. a na ts1!-, 6 ears n 234 (x) and f seg. a ts4 lg cr g, 5 ears M 235 # a, seg. Ig2 Dt su Y, 3 ears 1 236 # a, seg. Dt su Y, may seg. na ts4, 7 ears 309 - ko - Co 207 # ds , 7 ears » 200-209 # dm , 11 ears » 290 # ds, 3 ears 1 291 # la su, 2 ears " 292 if la su, seg. Tu gl3, 1 ear " 293 # la su, seg. Tu gl3 pr, 1 ear » 294 (x) pr dm, seg. ys v2, 7 ears " 295 # A a2 C R, seg. pr Y, 9 ears 1 296 if v2 pr dm, 3 ears " 297 # dm, seg pr dt, 5 ears 1 290 # A C R A2 a2 dv pr dt, 2 ears ti 299 A A2 C R dv dt pr, 9 ears rt 301 # A A2 C R dv pr v2, 3 ears “ 302 # A A2 C R dv dt pr, 2 ears " 3o]i # A B seg. PI Y py sm, Ig, 12 ears " 305 (x) A B pi Y bid, 1 ear " 306 (x) B pi Y zg3, 2 ears " 307 (x) B PI zg3> 1 ear » 300 # ra gl ij, 2 ears 1 309-310 # gl ij, 12 ears " 31? # gl ij ra, 1 ear 1 314 1 seg. vp^, 3 ears n 315 <,X) Ig gl4-, seg. v, 5, ears " 317 1[x) seg. c sh wx v gl4, 4 ears " 310 <[x) wx, hetero. for large internal knod on long arm of chrom. 9> 3 ears " 319 Iw R g nl x zd5 cross, 0 ears "320 1x) lg g colorless aleurone, may seg. d7, 6 ears " 321 (x) r zd5 colorless aleurone, 1 ear " 322 (x) A C Rr g li, 1 ear " 323 (x) li, seg. gl vl0, su, 1 ear " 32ft (x) y li, seg. gl vl0 su, ears " 326 1(x) A B PI Y3, seg. Y, 6 ear 11 s 327 (x) A B PI, seg. Y, ^ ears " 328 1(x) A B pi Y, seg. Y3 al, 6 ears » 330 1(x) A B pi Y, seg. Y3, 6 ears ” 331 I[x) A B pi, seg. Y3 al, 1 ear " 332 'fx) Y3, seg. Y PI, 1 ear " 334 (x) Y Y3j seg. PI, 6 ears " 336 (x) deep yellow endosperm, 0 ears ” 337 'Cx) and # A dm2 su y pi d lg j C R^ Pr in seg. ts2, 2 ears » 33s (x) and # A dm2 su y pi lg d j C R&, seg. v Ts2, *1- ears " 339 (x) and # A dm2 pr in su y pi lg d j seg. cr na, ^ ears " 34-0 # A c r £ g pr in y pi lg d j, dm2 Pvv Bn su, seg. ts, 3 small ears (x) and ?f A c Rg g pr In Bn su y pi lg d j dm2, seg. ts, 5 ears " 3̂ 3 # A c RS cr pr Bn y pi lg d j dm2, seg. g in su 314 ts2 d, 5 earsn .J+ (x) A c RS g pr Bn y pi d lg j dm2, seg. d in ts2, 2 ears 310 OJ Co 34b (x) » 346 # A C r& sh wx, seg. >1 s 3 u4 ,7 5 ears# a C r pr wx y, seg. ys, 10 ears » 348 (x) and # A c Rg P wx pr su y in, seg. sh, 7 ears » 349 (x) and # a C Rg pr in wx su, 5 ears " 350 * and t? a j lg B C rr pi Y, 6 ears " 352 (x) and # seg.b t vp, 10 ears >' 356 # seg. "bt, 4 ears l' 357 # seg. tiny plants, 2 ears " 35^ o.p • Y Gaspe Flint, few seeds B 359 (x) •' 360 (x) " 361 (x) (su gl3 x ws2), 2 ears « 362 (x (Y PI Py py x ws2), 2 ears " 363 (x) and # seg. pr Y ws py, 7 ears «' 364 7r (Bn gl v5 x ws2), 8 ears « 365 (x) and (j rns8 x ws2), 6 ears « 366 # (ws x c sh / + wx gi4) , 2 ears " 367 (x) ” 368 (x) » 369 (x) CL 1 7, \ xv / ' x * -* -*— —r — — O — * * ' " 370 U j and If (Pr nl2 x pr bm A er d), 6 ears n 371 (x) and if (su gl3 x nl2), 7 ears " 372 (x) " 337734 (x)«, # (A c R su x a C R nl2), 6 ears " 375 ir (A C r j x nl2), 6 ears " 376 (x) " 377 # seg, ms8, 2 ears " 37 8 # seg, .mbms8, 3 ears " 379 # seg, r ms8, 2 ears » 380 74 r seg rg3 R r ms 8, 3 ears » 381 # seg j R&S r ms8, 3 ears " 382 7jri seg j Rnj r ms8, 3 ears " 383 (x) » 384 (x) » 385 (x) « 386 (x) " 3g7 X cxX 1UL 7T u i i. v ci iwx i j j » 388 (x) and # Onondaga White inbred 12 years, 6 ears " 389 (x) and # West Branch inbred 9 years, 9 ears " 390 (x) » 391 (x) " 392 # Rustler (S44 x S46) Fg, 6 ears « 394 (Xj and 7T Hays and Johnson S2S3, 6 ears " 395 (x! and tr Hays and Johnson 7 years, inbred Gold. Bantam, 9 ears » 396 A Bb PI x lg gl2 b v4, 5 ears " 397 lg gl2 b v4 x A B pi, 3 ears » 4oi # seg. j or ij and lg, 3 ears »' 402 # seg. po, 5 ears " 4o3 # may seg. st, 6 ears " 4o4 # a c r A2 pr y, 6 ears « 405 (x:) and # ap B PI, few seeds 311 - k2 Co 14-06 # a B pi, 2 ears " 1+07 # a b PI, 3 ears 4-OS # A B pi, 7 e^ s " 1+09 open poll, a b pi, 6 ears " 410-411 (x) a b pi, few seeds " 4-12-4-15 F2 involving A B PI sm py W, 75 ears » 416 (x see. 13> 2 ears " 4-20 (x Fp involving A B Ig gl2 v4 PI ts , 5 ears 422 (x Fp involving A B pi gl2 v4- Ig gs2, ; ears 424 (x and # a yt na ts4- in various combinations, 6 ears 425 (x a lg2 Dt, very few seeds 428 (x A C R a2 b v2 pi, seg. bm2, 1 small ear 431 (x and # A Bb PI sm, ( ears 432 * seg. ra gl ij bd, 2 ears seg. 3, ms$, few seeds HP F2 involving gl4- yg2 c sh wx, 9 ears M-36 (: Pr g seg. R nl zb5, 1 ear ^37 U) zb5, may seg. g nl, 1 ear " ^39 (x)1 seg. bs vp, 4- ears " 1+41 (x)\ see. bs vp and striped, 4 ears It 44 6-448 (x? 3 r / V , seg. su, 15 ears » 449 (x) 3 r/Rr , 1 ear » 4-50 Beg. j r Rmb tm, 2 ears " ^51 s ,e mbg. 3 r R 4- ears « 4-52-4-54- seg. 3 r Rr ;̂ P « 1+56-4-57 (x) 3/+ r/Rgs, 3 ears »' (x) j/+ r/Rn3, 1 ear » 4-59 (x) j/+ r/Rn° PI, 4 ears 11 1+60 (x) J/+ r/Rn3, seg. sr " 1+72 (x) may seg. hf, 3 ears » 1+76 + A B PI, seg. su ba2, 34 .7 e9 aH I rs # may seg. bd, 3 ears " 1+81 (x) Tu su, 1 ear » 1455 (x) Oil Dent inbred 10 years, 4 ears " 486 U.S. # 204 x wx; br wx; bm3; A b pi lg glc. v4> 4 ears West . Branc , h . inb ,« 487 red 10 years, x g4 wx; A b pi lg gl2 v4, 2 ears Dutton’s Flint inbred 13 years, 2 ears Rustler inbred 7 years, 1 ear Kvakan’s smut resistant x A C R ac b pi v2, lear Bryan’s inbreds, 9 ears Open pollinated. Au au2 sh, few seeds du au au2 sh, few seeds _ Dt, .also na lg ts*! g in various combinations, 5 ears 498 # g4 wx, may seg. 16, 2 ears 499 # Tp gl ra v5 in various combinations, 3 ears ’’ 500 (x) a, seg. Dt lg C R PI, 5 ears " 501 # ar wx, few seeds ’ 502 open pollinated g2 A b PI, 1 ear 312 Co 505 (x) A Bb PI seg. Kn, 2 ears ” 507 (x) gi, 2 ears >’ 503 (x) g-15, 2 50 e9 ars" (x) and. # gl3, 2 ears " 510 (x) seg. Y 5 1 s4 u gl3 la, 5 earsn (x) r, seg. rnr Pr Mt, 6 ear 5 s» ig (x) seg. f v, 522 5 ears» (x) A C R a2 bt bv 1 pr5 , 2 f3 ew seeds (x) A C R a2 52 bt4 pr, v few seedsit (x) A C R A2 bt bv pr, few seeds » 525-526 # fr2, s 1 e1 g. 52 3 ij gl fr, 10 ears " # Supergold Popcorn 11 in 5 b2 r9 ed, 6 ears # A B pi, seg. YU- 11 , It, 2 ears 531 # y4 It a c r pr i 5 , 3 32 earsI' (x) and # Y4 g4 11 , 5 s4 e1 g. It, 5 ears (x) Y sk from Aus » 5 t4 r4 alia, 1 ear Open pollinated No. 3 Tr 5 is+ o5 me, 3 ears'* I No. 5 Trisome, 1+ e n 5 a4 r.6 s No. 6 Trisom »i 5 e5 ,2 1 ear # P br f bm2, ma 1 y seg. Ts2, 3 ears 554 # a B pi, seg. yg2, 1 5 smi 55 all ear A C Rs* 5 5 x6 r mr Pr, 1 ear» ‘‘Sweet Brittle” (x) a 11 nd5 5 x7 bs, 6 ears (x) Singleton C2 inbre 1 d, 553 3 ears (x) " C6 " 559 , 2 earsii (x " 013 " , 5 ears 1937 crop Co 37-1 Bryan’s inbred (x) and x red pigment in seedling leaves, 7 ears '« 37-2 West Branch inbred (x) and x g4 wx, 9 ears " 37-3 U.S. No. 204 inbred (x) and x g4 wx, 7 « e ars" 37-4 (x) and x ar wx, 3 4e . 7- a5 rs1 (x) and x bm3, o ears " 37-6 Oil Dent inbred x bm3, 1 ear " 37-7 U.S. No, 20j+ inbred x ra gl ij 3 b7 l,-3 9 ears | (x) and # lg B v4 A PI, seg. gl2^Ts, 1e ar " 37-9 F2 involving g4 gl4 yg2 c h wx, 3 ears » 37-10 | ra gl ij bd, 1 ear « 37-11 (x) gl ij, seg. ra fr fr2, 7 ears » 37-12 (x) F2 involving ra gl ij bd, 3 ears " 37-13 (x) A b PI, seg. py sm, 2 ears " 37-14) Fo involving West Bran | ch3 7- i1 n5 b) red and lg b gs v4 gl2, 6 ears ” 37-16 Luce’s Favorite (x) and x Onondaga White Dent, 10 ears " 3/-13 Cornell 11 (x) and x Luce’s Favorite, 3 ears » 37-20 (Luce’s Favorite x Onondaga Wn. Dent) x (Bloody Butcher x Cornell 11), 11 ears " 37-21 (Bl. Butcher x Cornell 11) x (Luce’s Fa 1 voritex Onondaga Wh. Dent), 9 ears 37-23 West Branch (x) and x U.S. no. 204; pbx; Sx Pr p ad an; yg3; bushy; c sh wx bp; 20 ears 313 Co 37-2° U.s. no. 204 (x) and x West Branch; c sh wx bp; zb5; p ad an; Gh; pbx; bushy; 25 ears 37-28 (x) c sh wx bp, 2 ears 37-^9 F? involving tu su dh, 3 ears 37-53 (x) a lg2 Dt, few seeds 37-54 (x) C R a2 bt bv pr y, 2 ears 37-55 (x) na cr gl v5 Y, v. few seeds 37-57 (x) C R a2 pi B Y, 2 ears 37-58 (x) zb5 y> seg. nl> ̂ ears 37-60 (x) C R a2 bt bv, seg. vv2c,, 2 ears 37-62 (x) g2 A b, seg. PI, 2 ears 37-63 (X a y Dt, v, few seeds 37-64 (x) a y Dt, seg. su lg2, 2 ears 37-67 (x) v5 gl, seg. Tp ra, 5 ears 37-6S (x) v5 gl Tp ra, 1 ear 37-69 # a, seg. na lg2 ts4, 2 ears 37-72 (x) au au2 sh, 2 ears 37-73 (x) F2 involving su gl3 J2, 2 ears 37-74 (x) and # A C R A2 Pr, seg. PI, 2 ears 37-75 (x) seg, Pr vl2, 1 ear 37-77 (x) and # seg. vl3, 3 ears 37-80 # seg, va2, 4- ears 37-81 (x) and # seg. wa, 2 ears 37-82 # Pr Y, seg. ms2, 2 ears 37-84 # seg. msB reddish yellow 4 ears 37-85 (x) and # seg. ms6 Pr, 2 ears 37-86 ms6 x West Branch, 2 e a an rs 37-87 (x) d # A B PI Y, seg. ms8 Ig, 3 ear 37-88 # Y, seg. ms9, 4 ears 37-89 # seg. ms10, 5 ears 37-90 (x) and # seg. ms11, 6 ears 37-91 (x) and # seg msl2 white stripes, 4- ears 37-92 (x) and # seg msl3, 6 ears 37-93 (x) and # seg. msl4, l ears 37-96 (x) pvv] may seg ms34, 3 ears 37-97 (x) and # seg. ms37 > 1 ears 37-9^ (x) and # seg. ms39 Pr Tu, 7 ears 37-99 ms42 x inbred, 2 ears 37-100 Fo involving PI sm pbx Pr, 2 ears 37-101 (x) A^B PI 0, seg. 1 w, a 3n d e a# r s37-103 (x) seg. yellowish green seedlings, 4 e 37-104 (x) a a n rd s # rather light green foliage, 1C r ears 1 37-105 (x) ather light green folia1 g0 e7 , seg. a v, 9 ears ' 37 -106 and dark green foliage, 6 ears 1 37-109 (x) vl2 , seg. fr, 4 ears ' 37-110 (x) y,_seg. gllO. 6 ears ' 37-Hl (x) su3̂ du, 2 ears * 37-114- (x) F2 involving A b pi su2 sb, 4 ears 1 37-116 (x) y^su2, may seg sb, ears " 37-H7 (x) y, seg. pbx " 37-H9 (x) Pr wx da ar sa, 5 ears " 37-120 (x) A B PI Sx Pr, few seeds » 37-121 (x) Y b gs2 lg » 37-122 (x) sy, 10 ears 314 y, seg. Pc, ( ears a lg2 d, seg. tsh, 3 ears and if A lg2 d, nay seg. ts4, 3 ears Y a lg2 ra2, 3 ears b u , silks all over ear, 3 ears Fo involving Ga su cross, 5 ears Ch, seg. gl v5, few seeds p ad, seg. an, 5 ears Fp involving Ga su, 3 ears Fp involving Ts3 v4- Rg, 2 ears Fp involving Ts3 vH Rg 0 sh wx, also seg. ' ?r Y, ^ ears p ad, may seg. an, few seeds seg. Pr dm3 yg3> ° ears Y P, seg. Og, 5 ears Y Og, 3 ears su, may seg. w4, 1 ear Fp involving Og and La inbred, 4 ears A~3 PI 1, may seg. w, 1 ear A C R A2 pr i, 7 ears wl su gl3 in various combinations, 3 ears Fo involving wl Ts5 su, 2 ears g!3, seg. su wl eeg. su gl3 Y, 5 4 earsTs su y, seg. gl, may seg. l 2 a, 3 ear-a lg , seg. Dt na, 4 ears na, seg. ts^, 2 ears seg. w, 1 ear Y gl, seg. de, 6 ears l Y, seg. de, 3 ears Y a yt, seg. na, 1 ear I Y, seg. bushy, 1 ear ) and # ij gl bd in ,various combinations, 4 ears ) y, seg. ra, 3 ears ) y br f , may seg. bm2, 1 ear ) seg. Y, 2 ears ) y pbx, 2 ears I* X7-' pr, seg. Vg, 2 ears ) an2, 1 ear ) Y fine stripe, 1 ear B.C., seg. A b lg gl2 v4, few seeds seg. na2 su Pr, 3 ears A lg g!2 b vk Yx corrugated leaf, few seeds ) y Dt, seg. na tsH- lg2 su, 1 ear su, may seg. la, 1 ear ) y v2 A C R a2 b pi, 7 ears ) A C R A2 bv bt, seg. Pr, 4 ears ) Y A b PI sm, seg. py, 2 ears 2 , seg. ms$, 1 ear ) yg2 lg c sh wx, seg. g!4, few seeds ) A C R a2 b pi v2 y, may seg, bm, 2 ears ) Fp involving A C Rs ̂ r B (mottled red), 2 ears :) Y, seg. bk, 3 ears 315 Co 37-193 (x) y g 3 l, s9 eg. bk, n y-i 9 (x) F2 1 ear involving bk bk2, seg. gl, 4 ears " 37-200 (x) seg. de, may seg. mi, 1 e 3 ar » 7-201 (x) seg. 1 an2 d, 5 ears 37-202 (x) Fg involving Trucker’s Favor 2 ears11 i 3 t7 e- 2 a0 n3 d mi, (x) A 'C R a2 bv bt pr, 1 ear " 37-203 (x) Wo Y, 1 ear « 37-203 No. 2 trisome x U.S. no 20 -̂, 3 ears «' 37-209 No. 3 1 - 1 , 2 ears " 37-213 No. 6 , 1 ear » 37-211 No. 7 , 3 ears »' 37-215 No. 3 , 1 ear i 37-217 No. 10 , 3 ears »3 7-219 # seg. n ms3 vl6, 3 ears ”37-220 and 221 (x) yellow striped seedlings, 3 17 - e2 a2 r”̂ 2 (x) homo virescent s 3 e7 e- d2 l2 i3 ngs, 2 ears it # yell* striped seedlings on very dark green base, 3 e «i 3 a7 rs-22^ and 225 (x) vir 1 escent 6 seedlings, 2 ears (x) and # seedlings tiny, virescent and white striped, 3 ears 37-227 # crinkly seedling leaves, 2 ears 37-223 (x) Amargo from Horowitz, 1 ear 37-229 # seg. vl9, 1 ear 37-230 # BUam 2 ears 37-231 T l-2b x Tl-2b, 1 ear 37-233 Australian x Siamensis, 3 ears 1933 crop Inbred I = U.S. No. 20̂ - (W-R) Inbred II = West Branch (W-W) Co 33- 1 F2 involving inbreds I and II, 1 ear » 33- 2 (x) pr, seg. Y ms7, 3 ears 33- 1 (x) seg. Y msl2, 2 ears 33- 4 x) Y, seg* ms42 su, 6 ears 33- 5 vxj F2 involving H mg, 3 ears 33- „6 (x) To involving inbred II and yg3 bm3, 2 ears 33-9 and 10 tx) F2 of no tillers x many tillers cross, 15 ears 33-11 involving inbred II and c sh bp wx, 5 ears 33-12 U) involving inbred I and c sh bp wx, ( ears 33-13 (x II and p ad an?, 1 ear 33-14 (x. I and " , ^ ears 33-15 (x) II and y pb+, 3 ears 33-16 (x) I and ” , 7 ears 33-17 Inbred I x y ra si; g1! wx; bm3, 3 ears 33-13 Inbred II x y ra si; g4 wx; bm3, fx? Pu?, 4 ear 33-19 x) In, seg. Pr w, 5 ears 33-20 7T seg. sk, 2 ears 33-21 (x) Pr y sp su, 5 ears 33-23 (x) Y d6, 6 ears 33-24 (x) a3 g, seg. Pr, 2 ears 33-25 (x) y Og, may seg. a3, 3 ears 316 Co 38-27 ( x ) Y zb4, 5 ears » 38-28 (x) Fo involving inbred. I and zb5 and possibly nl g, 7 ears I 38-30 'x) Y fs, 2 ears I 38-31 *x) Y mg, 2 ears It 3S3-33 [x) y Hs, seg. Tu, 3 ears I 3 x) dec y, 5 ears I ^-3738-4-0 .x Y v7, 4 ears II 38-44 (x seg. ms, may seg v!9, 3 ears II 38-45 (x Y v20 lg, 2 ears It 3 g—U-6 (x. Y 0, 6 ears I 3 2-^7 (x) y 62, v. few seeds It 3̂ -U-g (x) Y h, 3 ears II 38-49 (x) Y f 12 may seg. rns , 7 ears II 38-50 (x) Y f12 gl, Beg. su, 7 ears II 38-51 (x) a C Rg pr in wx^y, seg. su, 6 ears It 38-52 (x) a^ C R Y pr in, 4 ears II 38-53 (x) Pr, seg. vp, 4 ears II 38-56 (x) . vp4, 1 ear II 38-58 (x) ^ t sef ear It 38-59 (x) Rmt; 2 .ears tt 38-60 (x) A CR ni Pr, 2 ears It 38-62 (x) A C Rri&g pr P, 2 ears I 38-64 (x) y rr su, 6 ears 1 38-65 # seg. rns2, 6 ears I 386̂-0606 1(.xx)) bsee°g'.. ms2, may seg. tt 3 18 7- ,7 R 0 5 ear and 7 s1 n., , . ^ (x) and # seg. ms11 and ar-like stripe, 13 ears " 38-72 (x) Y, seg. v, 7 ears " 38-78 (x) Fp involving lg2 pm d, 5 e « 3 a8 r- s8 1 (x) y, seg. d2, 1 ear " 38-82 (x) Y sh, seg. d3, / ears « 38-85 (x) Y, seg. d5, 4 ears 3&-90 (x) sh wx, may seg. 16, 1 ear 38-92 (x) Y, seg. 17, 5 ears 38-93 (x) Y, seg. w2, 3 ears 38-95 (x) Y, seg. w3, 1 ear 38-96 (x) Y wx, seg. crinkly leaf, 3 ears 38-97 (x) sh wx Pr, seg. wll, 3 ear 3 s8 -98 (x) pr, may seg. v5 , 4 e » 3 a8 r- s1 00 (x) seg. v9, 7 ears " 38-IOI (x) A c Rg 1 su, seg. v9, 4 ears ti 3^1031(x) s «i eg> v 1 3 , 11 ear3 s8-104 (' x)' y vl8a, 1 ear " 38-105 (x) y vl8, may seg. 14, 1 ear » 38-106 (x) and # lg gs2, may seg gl2 v4 b, 2 ears 38-107 (x) and # ws3 lg, may seg pl2, 7 ears38-108 (x) involving Y g!2 lg v4- f 1, 10 ears 38-109 # lg gl2 ts V- in various combinations, 4 ears 38-112 (x) su gl3, seg. wl, 1 ear 38-114 # P PI srn, seg. py, 2 ears " 38-117 # seg. j ms8 vl6, 3 ears « 38-119 # Tso Og, 3 ears 317 4g - Co 33-122 # wx g^} 6 ears 33-123 # wx g4, 1 ear 33-126 (x) bm3, 2 ears 33-131 # pr sk, 1 ear 33-132 # A B PI Pr bra, seg. sk lg, 2 ears 33-133 (x) Pr lg, seg. sk, 2 ears 33-134 (x) may seg. lo, 2 ears 3^-135 # Y, seg. hf, 6 ears 33-136 # seg. Pr T5~6 s u , 3 ears 33-133 # y, _seg. Ig3 Rg and possibly d, 1 ea # Y r33-140 wx. seg. ar, 5 ears 33-143 (x) and # Pr, seg. g tw3, 3 ears 33-144 (x) seg. bax, 1 ear 33-146 # seg. ba, 3 ears 33-146 # seg. ba2, 2 ears 33-147 (x) may seg. ra2, 2 ears 33-l^-3 (x) Y a lg2 ra2, 2 ears 33-150 (x) ^2 involving pr zb f ys, 4 ears 33-153 (x) seg. at, 1 ear 33-154 (x) gl, seg. bk, 2 ears 33-155 (x) Y bk2, 3 ears 33-159 (x) Y gl fl2, 1 ear 33-179 (x) zb4 br f, may seg. bm2, few seeds 33-137 (x) and # Og g li, *+■ ears ' 33-139 (x) a B PI C R Px Y, 5 ears > 33-191 (x) A C r g y. 3 ears 1 33-192 (x) A B pi C Rg Pr Sex y lg, 2 ears 1 33-193 (x) A b PI Y sm, seg. py, 3 ears 1939 crop Co 39 (x) involving inbred I and g3 49- wx, 3 ears„ - (x) » and si ra, 5 ears " 39- 3 (x) ,2 " and bra3, 3 ears " 39- *4 (x) II and si ra, 7 ears " 39- 5 (x) " and bm3, 10 ears " 39- 6 (x) " and g4 wx, 3 ears " 39- 7 Inbred II x Rmb. In? Pr; Y o v2; zb4 br f bm2; A C Rrg pr P; w3 lg glS;'sp su Pr; RE RS m; b. y su; yg2 sd wx gl lg; a,-P B PI P; lg2 d; v7; Y fs; sk v ; gl y4; n b rown striped; zb4; lg gl2 v*+ r; Y o v2; r8t, 32, ears " 33- 3 Inbred I x lg gl2 vU fl; fs; sk; y wx v gl4, a B PI P; A C Rrs pr p->vV Vv .; vlg; brown striped; Y o v2; zb5 nil; Pm > v7 > WX v gl4; sp su Pr; Pr In?; ws3 lg g!2; Y fs; yg2 sh wx gl4 lg; rot; lg2 d; zb4 br f bm2; y wx v gl4; RSg; A RnC j Pr; v7 ; a d lg2, 52 ears » 39- 10 In Pr x inbred I, 2 ears « 39- ll # seg. sk, 3 ears 318 Co 39- 12 (x) and # sp su Pr, also crossed to inbr 6 ed I and II, ears 39- 13 # zb^, also crossed to inbr. I and II, 3 ears 39- 15 rst x inbred I and II, k- ears 39- 16 A C Rn ̂ Pr x inbred I and II, 5 ears 39- 17 rSS Pr x inbred I, few seeds 39- IS A C Rr^ pr P x inbred I and II, ^ ears 39- 19 rr y su x inbred I and II, 6 ears 39- 20 Y v7 x inbred I, 1 ear 39- 25 (x) and # Y fs, 3 ears 39- 27 (x) lp Ts v4-, 2 ears 39- 23 (x) lg gig ts v4 in various combinations, 3 ears 39- 31 # ws3 lg gl2, 1 ear § 39- 32 (x) lg gl2 fl, 3 ears 39- 35 (x) gs2 gl2 b v^, 1 ear 39- 37 (x) d and lg2 d, 2 ears 39- 32 (x) lg2 d, 1 ear 39- (x) lg2 d, 1 ear 39- l l # j, seg. ms3 vl6, 3 ears 39- (x) y sh wx v gl^, 2 ears 39- K (x) yg2 sh wx lg gl^, al Ts to crossed to inbre 3 d II, ears 39- '+5 (*) and # y wx v gl1!, 3 ears 39- 1+6) Y, seg. su Ts6 Pr, 3 ears 39- t+7) 39- (x) y zb5 , may seg. nl, 1 ear 39- H9 (x) zb5 , seg. Y, 1 ear 39- 50 (x) bm3, seg. Pr Y sh, 4 ears 39- 51 # seg. ms7 39- 53 # seg. ms4-2 gl, 5 ears 39- 55 (x) seg. d2, 5 ears rt 39- 60 (x) Y du2, seg. du sua , 1 ear tt 39- 61 (x) Y seg. du2 du suam, 1 ear tt 39- 67 (x) A b PI Y shi P, 6 ears G. A. Lebedeff 319 V. INDEX OF SEED STOCKS Co 12, l4, IS, 19, 20, 3S 1 ,0 6 *10, w , q 4i - 5, 1 50 03 ,. 51, , S31 ,0 7, 110 1 ,2 6 111 1,3 7 114-116, 123, - 125> l4o~l4l, 143, 149, 177» 160-1^2, 2 l2 &4 5, > 273, 274, 295, 3 29S, ip? 26-33 291 9, 301, 302, , 337-340, 34 3 19 -6 350, 369-370, 3 ^ 3 7; 6 , h o ^ - m , ^23, H 3 -7 31, 502-54, 37 , -5 57 22-53 27 *16 , 0 37-3 87 , 6 32 7-13, - , - , 37-7*1, 37-125. 37- 3 1*7 1- 3 2 ,179 37-180, 37-1 3 81,6 2 37-187, 37-203,£ - 38-, 6 03 ,2-132, 38-189, 38-191, 38-192, 38-193, a2 Co 299^ 301, 302, 52^, 37-24, 37-143, 37-180. a3 " 38-24, 36-25 ad » 37-131, 37-1 • 3 62 ,8 1 3, 82 -18 32 ,, 3^1- 93 al " 269 32, 827 30 3, 1 , 2 37 91 -, 47 - „ , - lk an 37 13" 137 3- 816 17 3, , 3S~l4 an 2 37-201 ar » 67, 501, 37- 119, 38 " - l>1 +8 0 ara S as " 216, M-01 at " 258, 38-153 au » 4-9*+, %5 , 37-72 au2 3 38- 133, 38-189, ,38 2 -6 13 9bax C 2 o , 264-, 38-144 ba » 264, 38-145 ba2 n 7g-l46 bd w 172) 259, 260, 479, 37- 10 , 37- 12 , 37-159 be bk » 171, 352, 356, 14-39, 44l , 3 3 78 -- 115 94 7, 37-198, 37- 199, bk2 » 556, 37- 197, 37- 199, 38-155 bl brn ” 33^ ’ 52-56, 116- 118, 294, 295-297, bm2 . 337-344, 552, 37-161 bm3 . I S 503, 37-5, 38-17. 38-18, 38-126, 39-2, 39-5, n 39-50 bmx 3n " 6 / 7 1 3 ^ 232, 340, 342- « 345- , 36, 4 bp 68» 6974, 372 -5 2S 8, , 2 38- 11 , 38-12 br 66, 359, 552, 37-16 I 1,p be £ 3p 8 -179 35 43 47 .bt h , , 17*4, 297, 298 3 , 7 295 94 , 33 07 26 , 0 5223 -7 52- , - , -1 *8 10 , , 37-203 bt2 bv " 33 ’37, 53-54, 114, 115, 258, 298, 299, 301, 6 32 02 2-52*1 37-5*1, 37 -60, 37- 180 3 ,8 37-203C . S l l ; , 40, 4 1 ,10 451 , 1 1 50, 51, S3, 81 82 ,, 6 89, , 911 ,2 4, 125, , 12 1 73 ,7 129, 130, 131, 13^ , l*lN 181! 295! 298, £99, 301, 302, 322, 320 34-1 34-5-3^7, 3^9; 350, 375, ^ > 37-5^> cr Co l ^ g ; 2 4 ^ 2 5 , 26, 125, 131, lM , 162, 215, 2<*. 339, 3!i-3, 37- da 1 1 5 8 51 dh » 431, 37—^9 dx d " 10; 370, 37-12^, 37-125, 38-78, 39-37 d2 » n - 12, 3^-gl? 39-55 d3 « 70-72, 30-02 d5 it 2—4-, 30-25 d6 30-23 d? 320 da 495, 37-119 dex Dt 2 £ S 52 $ 6 ^ 2 ! % ! £ 2°97. 500, 37-53, 37-63, 37-64, 37-14-9, 37-176 du f 130^ 1397 258?°267-26°; 359, 363, 4oi, 552, 37-161, 33-179 f ia 10; fl - 32-100, 39-32 f 12 " i4-5, 14-6, 30-4-9, 30-59> 30-159 fr and 2 Co 66, 525, 526, 3/-H fs Co 30-30, 39-25 fx g " 21° 9*1, 99, 100- 1023̂ , 2 13^, 1363 ,6 7 319, 320, - 334 2- 24 ,-, y w , , 4-36, 437, 497, 511, 37-50, 3.-1 >2, 3*-2$, 30-20, 30-107, 30-191 g2 « 37-62 gl i« 67, 73, 498, 37-3, 37-9, 38-17, 38-18, 38 381 -2 13 22, - , 39-1, 39-6 gx " i0, 25, 26, 284 (la S1 (b’ ° ’co)22° g 499,125, 526 308-313, 364, 373,, 37-11, 37-55, 37-67, 37-68, 37-130, gl2 Co !^~7?9220, 23^, 273-279, 397, ^20, 37-81, 39-28 I S : W i % % W W : 515; 3 ^ . e l ( 5 - 1 0 ) Co l l , 242-24-7, 508-509, g 3l 7x - 110Co 23, 104, 113, 175, 25^-258, 323-324, 3S-50, el 3 6-( 1H 7a 9djinof f ' s ) Co 225-231 gs Co 401, 37-1^, 37-1 | 5s 2 _ » n 6, 272, 422, 37-121, 3S-10O, 39-35 h " l48, 38-48 hf 1 257, 472, 38-135 Hs 1 38-33 321 I Co 176—1/^> 16 ^6 2— 1$5 t 3 l 143 ij " , 309-313, 525 52 - -7- . y irQ 1 62 , 7 37-7. 37-1M 7 12" , 1 17 , 9 31 72 1 in 9, 135, 137, - 21 ->9 , 337— 3^5 > 3^s . 3^9, I I nb cr re od ssed*withestoojjs^Co 36-6, 32-12, 39 39-6 4, 39-5,- , 39-S, 39-10, 39-12, 39-13, 39-15, 39-1°» Inbred II crossed 39-7 39 1 32 9-1, 39-2, 39-3,- , 39-13, 39-15, 39-16, 39-12, 32 19, 39-24-, 39-44 it c£ 5|?l’ 17 0 4-137 177, 182, 185, 333 7-6 39 44, 3’ 503 ,7 ,5! 377-322; 433, 446-454, 456-460, 37-124, 37-219, 32-117, 39-4 02 " 37-73, 37-147 Kn " 1 5 1 , 505, 37-161 Knobs " S3, 198, 3lS 1 " 37-IOI, 37-142 12 » 49-102 13 " 416 14 » 92-97, 38-105 16 " 73, 74 87 18 17 » - , 38-92 lx 1 1 112 la t 391-293, 510, 37-148, 37-177 1 cr „ Y l , & i, 12 cni a 4- , 0 169 -8 181 , 14 21-12 25 5, 1 52 } , 55, , 5 9, 6- 133 0, , S, 130, -l4i , 1^3, 185, 221, S717' S720' 337-344 ’3 3 51, 396 39*7, 401, \ 4l f i v 17: : ,i 4r 2 2 77- 15 8 : 8 ?, : 0 3 &7-6 ,9, 3 3 7-126 19 , 3 33 8-41 53 , 3 38-106^ l L ! 3 2 8^5 192,3 60 39-3 26 7,9 34 92 -3 31,S 39-35 2,-; 00 39-4, 4 lg2 Co , 125, 37 1 , 2 35 7-53 37 , 1 37-64, 37- - 124, - 26, 37-149, 3 ,8 -78, 39-37, 39-39 ig 3 « 3S-13g li 1 322-32^, 3^7, 3&-lg7 lo « 29, 30, 3^-13^ mg 3S~5, 3&-31 mi 37-200, 37-202 mr ms2 74-78, 37-82, 38-65* 3s ms 5 37 - 66 —si ms6 37-85 . ms7 ms8 365! ’3 7 n 5433, 37-87, 37-184, 37-219, 38-117, 39-41 ms9 37-88 mslO 37- 89 ms 11 38- 70, 38-71 msl2 37-91, 38-3 msl"5 " 37-92 msl4 " 37-93 mslf " 216 msl8 " 55, 56 , _ ms 20 " 103, 104, 38-72 ms37 " 37-97 ms39 " 37-98 322 ms 4 2 Co 37-99, 3f;4, 39n -53msx na ’2S3/2S6,’337 , 338, 339 3 ,7 - 35 ^5 1 , , 3 47 2- 46 .9 , 37-1*9, 37-150, 37-157, 37-176 na2 nl 319^ 376, 1+36, '137, 37-58, 38-28, 38-48 n/!2 o S t i ’ S U 6?. 37- Og 138! 37-139, 3 7 - ^ ^ 38-25, 3 ^ 1 1 9 , ^ 8 - i S ^ ^ ^ p 224,22 ^ 2 7 i ! 3io,33i8, 359, 3^8, 5 3 58 2, 1 31 74 -, 1- 38,39-67 Pb 107 ptA pbx 37-110, 37-164, 38-15, 38-16 Pc 37-123 Pg 10, 94 Pg2 91,8 82, 115„P6a 89 pgx 55, 92, 107, 185, 1 pk po PI : 3̂ 132(1 ^-133, 38- ^ 9/ 38-192; 38-193, 39-67 pm pr : S - l j f . ’jfef i 7 r - & P . Y 3, 14., 57-61, 303-305> 3P2, 363, ^12-415, „ R ? - { l ’ g " xS ; ^ o l S , 41 52 , 3 51 03 , 7 5 1, f3, 9- 1, 10, 5l -14 1l 3, 179-185, 2 9 18 8, 8 ,2 9 19 8, 9 ,3 0 21 2, - ,3 202 7, 5 ,3 37 9- 53 ,£$6 5 0, 367, 3754 -5 36 o- 24 ,6 0 4, 06 77 74 5^ 17 4- ,i ln 37 -53 47 ,- 17 39 7- 573 ,7 - 318 (-0 6, 0,371196/ 1 2 0 33 7- 187, 37- -lo8, ,38-51, 38-52, 38-58, 3 38 8- -6 52 9, , 3 38 8- -1 60 062 1, , ra " , 6 3 38-189, 38-192, 308-313, 499, 3/-7, 3/ 3 -7- 16 07 , , 373 -7 -68 , , 373 8-17 ,, 3&-1S, 39-2, 3>-4 ra2 37- 126, 38-148 rax 38- 147 Rg 37-134, 36-138 Rs 151, 256 rs2 255 3 130 Sx 37- 120 sa sb 28o(1l7, 37-114, 37-11 Sex 3 68- 192 Sc sh 04̂ x)l x6 x S ty-H- ^5, 67, 6 f S? ,: 7I 0-k 7g 3,^ ’ 7i 5l ~l 7; 132 9> , 138,1 3 9 , 149, 224, 315, 317 323 Co 346, 3H-S, 366, 14-34, 494, 495, 37-9, 37-28, 3 37 7-135. -185, 3S-1 1, 38-12, 38-90, 33-97, 39-43, 39—44 SI 258 sk 116- 118, 166-170, 39S, 38-20, 38-131, 38-132, 38- 133, 39-11 si 62, 63, 232, 38-17, 33- 18, 39-2 5 ,7 36 91 -4sm - , 303-305, ‘+12-415, 431, 37-13, 37-100, 37- 131, 38- 114, 39-67 sp 27, 28, 38-21, 39-12 sr 269, 270 st 4o3 su 27—30, 38, 44, 45, 51, 72, 101, 1012 23 , 10;,, 119-121, , 125, 128, 129, 13 1, 132, 134-139,142, 152-150, 188, 189, 224, 236, 237, 291-293, 307, 337-344, 346, 348, 361, 371, 374, 395, 431, 510, 37-49, 37-73, 37-128, 37-133, 37-140, 3 37 7-144- 37-14o , —177, 38-21, 38-5 1, 38-64, 38-101, 38-112, 39-12, 39-46, 39-4? su2 37-114, 37-116 suam 37-230 sy 37-122 tn 31, 32, 357 „ Tp 64, 499, 37-67, 37-68 Trisome 544-546, 37-208, 37-209, 37-213, 37-214, 37-215, 37-217 ts 276-279, 37-8, 39-2 1 73 ,11 31 93 -6 23 ts2 - , 258, 337-340, 342-344, 552 ts3 ts4 13-21 !’lf+l~ 1^2, 283, 284, 286, 424, 497, 37-69, 37-124, 37-125, 37-150, 37-176, 38-109 Ts5 37- 145, 37-148, 37-177 Ts6 38- 119, 38-136, 39-46, 39-47 tsx 23, 1 7 1, 220 Tu 236, 237, 292, 293, 361, 481, 37-45 tw3 38-143 va 178 vx 26, 47, 48, 82, 103, 104, 108, 166, I67, 171 178, 257, 2 ,5 8 176, , 261, 262, 264-266, 283, 234, 315, 320, 338, 340, 348, 403, 518 V 1517 39-43 39-45 v2 33/ 35-37, 39, 47, 52-54, 114 2 ,9 4 112 59 ,6 113 90 -1 1223 ,0 217, - , , 2, 372, 428, 37-60, 37-179, 37-18/ v 4l, 50, 51 v42 6, 7 . 8, 114, 115, 140, 220, 221, 234, 272-279, 396, 397, 4iy, 420, 422, 37-8, 37-14, 37-15, 37- 134, 37-135, 37-171, 38-106, 38-108, 38-109, 39- 27, 39-28, 38-32 v5 22-25, 64, 212, 308, 364, 373, 499, 37-55, 37-67, 37-68, 37-130, 38-98 v6 162-164 v 160, 16 1, I65, _ y 3o< 8-4g vo 152-156 v9 157, 15S, 38- 100, 38-101 vl2 37-75, 37-109 . vi3 37-77, 38-102, 38-103 324 VlA Co 72 vl6 » 37-219, 3 ^ - H 7 » 39-^ I 1 vi7 2^3 V lg I 95-97, 323, 32^, 3^-104, 3&-lC)5 vl9 I 37-229 v20 I 98, 3S-i+5 va2 M 37-go v"b I 266 Vg I 37-165 vp I 91, ?&-55 vp2 I 4g, 49 vp^ I 90. 31^, 38-5 1 5rx I 3U-, 229, 263, 310, 313, 336, 33 f w I 190, 1+12-1*15, 37-101, 37-1^2 V'2 I 190, 193, 19^, 38-93 v/3 I 190- 192, 38-95 w4 I 137- 1 0̂ wll » g4-g9, 38-97 wa " 37-gl Wc 37-205 Wh 65 wl 37-144, 37-J-1+5. 38-112 WS 359, 360, 363, 366 ws2 361, 362, 364, 365, 367 ws3 wx il"3l9, 34, 38, 44, 45, 63, 70, 7 1, 73, 79, 81, 83-39, 123, 128, 129, 132, 1?S, 139, 176, 17S-131, 133, 184, 188, 1S9, 213, 224, 229, 257, 315, 317, 318, 346-349, 366, 434 498, 501, 37-2, 37-3, 37-4 , 37-9, 37-28, 37-119, 37-1 3 33 5,1 1 37-3 13 85- , -1 ,2 , 38-5 1, 38-96, 36-9/, 38-122, 36-123, 33-140, 39-1, 39-6, 39-'+3, 39-44, 39r45 Co 22-26, 4o, 57-61, 66, 75-/8, 103, 104, 123- 1 10 3’, ^ _lli2, 144-149, 160-166, 1/5-189, 198-199, 206- 215, 224, 231, 234, 23s, 239, 255-263, 303-307, 326-350, 358, 364, 365, 377, 383-396, 3/-55, 37- 57, 37-138, 37-181, 38-189, 38-193, 39-44, 39-46, 39-4-7, 39-67 Y Co 326, 328-334 Y£M- 529, 531, 532 yga yg2 315, 434, 554, 37-9, 37-185, 39-44 yg3 37-137, 38-5 ys 36, 39, 41, 46, 47, 173, 217, 294 ysx 173, 347 , , yt 13, 283, 424, 37-157 zb̂i- 3S-27, 38-179, 39-13 zb5 319, 321, 436, 37-58, 38-28, 39-49 zbx 107, 38--150 zg3 306, 307 zl 216 Translocations Co 19g-202, 37~231> 37-232 0. A. Lebedeff 325 VI. HISTORICAL NOTES ON MAIZE GENETICS COOPERATION Mimeographed letter of April 12, 1929 mentions "Cornfab" held in Or. Emerson’s room in N.Y. hotel at t he time of the Christmas meetings, 192501 coming from female plants heterozygous for the two chromosome types carried the abnormal chromo- some 10. _ A duplicate of the seed planted in 1939 was planted in 1940 but only 62.8 percent of the individuals in a population of 4>922 possessed the abnormal chromosome. Since the two lots of seed were identical it appears that environmental conditions influence the segregation of the hetoromorphic bivalent. This behavior is similar to that found in certain insects where temperature differ- ences determine whether the X or Y chromosome is extruded into the polar bodies. Singleton found a marked effect of the female parent on the functioning of spl pollen. Tests were made using four different r-testers to determine if a similar situation existed for sp2. The data obtained show no indication of an effect of these female parents on the functioning of s£2 pollen. Jenkins gave the writer a selfed stock homozygous for mottled aleurone. He had found it extremely difficult to get a homozygous stock in which all seeds showed mottling since the mottled condition is extremely susceptible to the action of modifiers. This strain was turned over to the writer because it seemed possible that this case was similar to the a.-Dt situation where one gene stimulates the mutability of another. The mottling proved to be caused by an r allele and was not due to another gene causing r. to mutate. This allele is a new member of the R series. The mottled condition resembles most closely that produced by a single dose of R. It is not the same as the marbled and stippled alleles found in certain strains from Mexico and South America. M. M. Rhoades Connecticut Agricultural Experiment Station, New Haven, Connecticut The "miniature seed" gene which markedly reduces the amount of tissue in the endosperm and embryo has no effect upon pollen tube growth and little or none upon plant growth. This is additional clear evidence that nuclear factors have a particular time for their action and are specific for certain tissues. Wire stapling pliers are being used by many corn breeders to fasten paper bags on tassels and ear shoots in place of wire clips. The stapled bags are more secure and take less time to put on. The cost of the staples is about the same as for paper clips but more have to be used. (Stapler and staples made by Neva-Clog Products, Inc., Bridgeport, Conn.) D. F. Jones 341 1• The mottling factor was given the symbol Mt in the Cornell Memoir 180. we have tested several stocks for mottling and have found all except one, C626 purple flint, to produce mottling in seeds of the constitution r r R. However C626 suppresses mottling when the pollen is applied to any r r stock. Hence, it seems to us that mottling is the recessive condition and nrt-mottling dominant. In 194-0 evidence that the mottling factor mt and r are allelic, was obtained. The inbred C78 A C r pr mt (mottling) had been crossed by C626 A-Q-RJjr.Mt (no mottling). The F1 hybrid was selfed and also pollen was applied to a r_ mt stock. One ear back- crossed gave 120 colored (none mottled) and 133 colorless. Three selfed ears gave 82$ colored (no mottled kernels) to 268 colorless. Although these data are fragmentary they indicate that R and Mt are allelic or very closely linked, much closer than the 12% of crossing over origi- nally calculated by Kempton. Further evidence will be obtained in 1941* I should be glad to receive additional stocks of a C R that are known not to produce mottling. 2. Status of Connecticut Sweet Corn Hybrids. Possibly the maize geneticists will be interested in an item re- garding the practical phase of genetics. Sweet corn hybrids developed by the Connecticut Experiment Station are increasing in use each year. In 1940 approximately $00,000 pounds of seed were produced. This amount is sufficient to plant $0,000 acres or 10/ of this production had C13 as one parent. This is an early inbred almost immune to bacterial wilt. The use of this inbred in the early hybrids has practically solved the bacterial wilt problem for early corn. This inbred was first dis- tributed in 1936, 73 pounds being sold. Four years later it was used in the production of approximately 475,000 pounds of seed. The three principal hybrids comprising this inbred are Spancross (C4.13), Marcross (C6.13) and Carmelcross (P39. C13). Considerably more seed will be produced in 1941 as well as seed of three new hybrids, C23.P39, C27.P39, and Cl$ x C13. A letter of March 3 from one of the leading producers of hybrid sweet corn seed states that now Marcross (C6.13) is second to Golden Cross Bantam in poundage, and that all open pollinated varieties are falling off rapidly. Hybrid corn is one of the best examples of the contribution of Genetics to practical agriculture. b. R. Singleton Endosperm divisions have been examined further for determining types of aberrant mitoses in lines showing high rates of mosaic formation on the mature kernel. Evidence for a relation between aberrant chromosome 342 divisions arid observed genetic changes was obtained from control pollinations• The female parent was the same in both crosses. The resulting seed of one cross gives a high frequency ol variegation, whereas from the other pollen parent there are very few or no mosaics observed. Cytological study of the endosperm divisions from both pollinations (10-12 days after pollination) showed a mean difference in percent of aberrant divisions of 3.24 (3431 divisions observed. P = .01-.05). This is a highly significant difference although many of the aberrant divisions are probably associated with changes that would not be observed genetically. F. J. Clark Cornell University. Ithaca. ft. Y. I am indebted to Dr. M. J. Murray for indispensable help in making the records to be reported here. The order of br f - as noted in the News Letter of 1940, page 17, Bryan (News Letter 1938, page 5) had questioned the published order of the genes br and f . My report oi last year v/as not wholly satisfactory because I was obliged to limit it to plants recorded as f. The records reported here were made last summer and are taken mostly from 5-point tests involving br f an and, in addi- tion, £s_ or^bm2 and another chromosorae-1 gene or trans- location. They are assembled here for more ready reference as 3-point tests (items 1 and 2 below) Regions Item Genes 0 1 2 1-2 Total 1 br f an 512-376 26-25 78-125 12-3 1157 888 51 . 203 15 4 • 4f- 17.5$ 1.3% br f an 1109-853 26- U 92-73 7-2 2206 1962 70 165 9 3.2?; 7.5$ 0. 343 Item Genes 0 1 2 1-2 Total Reference 3 br f an 347 22 77 7 453 1 •L.’40, 4 • 8/0 17.0% 1.6$ p. 17 4 br f an 760 40 156 4 960 L.S. ’35, 4 • 2/b 1 6. 3% 0.4/c p.35 Total 1-4 br f an 3957 183 601 35 4776 3 . 8% 12.6% 0 . 7% 5 br f ad 975 47 141 1166 L.S. ’35, 4.0£ 12.1% 0.3% p.35 6 as br f 263 93 21 0 377 L.S. ’35, 2 U .T ,l 5.6^ p.35 7 br f Kn 446 21 H 8 25 640 N.L. '38, 3.3# 23.1% 3.956 P- 5 Item 2 (above) includes cultures involving translocations which apparently reduced crossing over. Both lots indicate the order to be br f an. Results reported in last year’s News Letter (item 3j and various records published in the Linkage Luminary (items 1-6) are included for comparison. The locus of ad is very near that of an and, therefore, to the right of br as is Kn also, while a_s is certainly to the left of br. Bryan’s records are repeated in item 7. It is obvious from these records that, in my material, f is to the right of br. Bryan’s records do not agree with mine, but they are not wholly conclusive, because, on the assumption of either order of br _f, the double crossovers are so nearly equal to the single crossovers in the short region. Loci of chromosome-1 translocations. Further tests of the linkage relations of several chromosome-1 translocations have been made. The genes included in these tests are bjr f an and either £s or bm2. These records indicate that Tl-6a, Tl-lOa, Tl-7b and Tl-7c are to the left of br in the order given here with Tl-6a relatively far from br and Tl-7c relatively near it. Tl-5a appears to be very near to and to the right of f, between it and an. Tl-3d and Tl-4 are between an and _gs. and relatively near an. Crossing over percentages between these several translocations and br, as reported here, are, 344 x'or the most part, in close accord vrith those reported by Anderson (b. L, 1938, p. 6). Agreement is good also bet/eon the placements reported here and Anderson’s cytological observations, except lor TI-7c. Five-point Translocation Tests Tl-6a : + Tl-10a : + Tl-lOa l + Tl-7b : + Tl-7b : + + : br f : br + : br + : br + : br Region + : f + : f + : f + *« Xx? + : f + : an + : an + : an + : an + : an + : bm2 + : gs + : bm2 + : gs + : bra2 0 137 118 73 93 110 1 30 5 8 4 3 2 5 2 1 4 3 34 14 18 * 3 7 4 101 55 52 17 59 1-2 1 1-3 1 2 Jc / oC 1-4 17 5 2-3 2 1 oe 2-4 6 1 10 1 3-4 17 1 1 1 1-2-3 1 2 1 1-2-4 1 1-3-4 1 2-3-4 1-2-3-4 Total 352 207 171 126 179 T-br 14*2 T-br 7.2 T-br 8.8 T-br 5.6 T-br 1.7 T-f 17.3 T-f 8.2 T-f 9.4 T-f 3.7 T-f 1.7 T-an 31.2 T-an 13.5 T-an 26.3 T-an 10.3 T-an 5.6 Percent T-bm2 48.4 T-gs 38.2 T-bm2 47.4 T-gs 23.0 T-bm2 38.5 recom- br-f 4.2 br-f 2.9 br-f 0.3 br-f 4.8 br-f 0 bin*- br-an 17.9 br-an 10.1 br-an 18.7 br-an 9.5 br-an 3.9 tion br-bm2 45.1 br-gs 37.7 br-bm2 44.5 br-gs 20.6 br-bm2 36.9 f-an 14.5 f-an 10.1 f-an 17.0 f-an 4.8 f-an 3.9 f-bm2 46.2 f-gs 38.7 f-bm2 46.2 f-gs 19.1 f-bm2 36.9 an-bra2 39*9 an-gs 30.4 an-bm2 40.8 an-gs 15.9 an-bm2 33.0 345 - 13 - Tl-7c : + + : br + : br + br + : br + : br + : f + : f + f + : f Region + : f Tl-5a : + + : an + an + : an + : an + : an Tl-3d : + Tl-3d + Tl-4 : + + : gs + : bm2 + • gs + bm2 + : bm2 0 160 142 119 59 185 1 1 5 5 2 4 2 9 6 4 4 4 3 4 1 4 4 20 72 9 36 125 1-2 3 1-3 1 1-4 6 5 1 1 3 2-3 1 1 2-4 2 3 1 1 3 3-4 1 2 1 2 8 1-2-3 1 1-2-4 1-3-4 1 2-3-4 1 1-2-3-4 Total 207 237 141 106 338 T-br 2.9 br-f 8.8 br-f 4.2 br-f 2.8 br-f 2.4 T-f 6.3 br-T 9.4 br-an 7.8 br-an 8.5 br-an 3.6 Percent T-an 12.6 br-an 26.3 br-T 9.2 br-T 9.4 br-T 7.7 recom- T-gs 16.9 br-bm2 47.4 br-gs 13.4 br-bm2 40.6 br-bm2 40.5 bina- br-f 6.3 f-T 0.3 f-an 3.5 f-an 5.7 f-an 2.4 tion br-anl0.6 f-an 18.7 f-T 4.9 f-T 6.6 f-T 5.9 br-gs 17.9 f-bm2 44 • 3 f-gs 17.6 f-bm2 39.6 f-bn2 40.4 f-an 5.8 T-an 17.0 an-T 1.4 an-T 2.8 an-T 4.1 f-gs 14.5 T-bm2 46.2 an-gs 8.5 an-bm2 35.8 an-bm2 40.2 an-gs 15.0 an-bm2 40.8 T-gs 8.5 T-bm2 38.7 T-bm2 41•4 3* Tassel-seed 3 and tassel-seed 6 - The results of tests reported in the 194-0 News Letter by Linastrom (u. 25) ana by me (p. 16) suggest that Ts3 is between an and £s, while !Vs6 is near bm2 and probably to the right. The records reported by Lindstrom, tho conclusive in shoving that Ts6 is near bm2, are inconclusive v/ith respect to whether Ts6 is to the right or the left of bm2. Uhere one region is as long as that between br and dm2 and the other as short as bm2 to Ts6. double crossovers are apt to be as frequent as are singles in the short region. My last year’s records, involving an and either £s or bm2 are unsatisfactory because of the wide differences between complementary classes of crossovers. The records 346 presented here are equally unsatisfactory for the same reason. They are given first in a table as 4~ and 5- point tests with complementary crossover classes combined. Four- and five-point tests with Ts3 and Is6 + : br + : br + : br + : br + : br + : an + : f + : f + : f + : f + f + : gs Regions + : an + : an + : an + : an + i an Ts6 : + Ts3 : + Ts3 : + Ts3 : + + : gs Ts6 : + + : bm2 + : gs + : bm2 Ts6 : + + : bm2 0 88 68 104 82 26 152 1 4 7 11 6 2 56 2 21 15 22 32 12 35 3 21 14 19 35 22 11 4 33 30 31 1 1-2 4 1 1 16 1-3 1 5 1 1-4 2 2 2-3 5 3 3 2-4 3 9 16 3-4 16 5 19 1-2-3 4 1-2-4 1 1-3-4 1 2-3-4 2 1 1 1-2-3-4 Total 138 151 170 235 67 271 Percent Recombination br-f 2.1 br-f 5.9 br-f 11.9 br-f 6.8 br-f a- * rj c.n-̂ s 26.9 br-an 16.0 br-an 22.5 br-an 2 c. 9 br-an 23.1 br - an -5*4 , n-xs6 33.6 br-Ts334* 6 br-TsO 34*4 br-Ts3 33.0 Ux i~. 46.8 br-Ts6 53.7 an-1x2 38.0 br-gs 42*0 br-bm2 44-4 f-oP. 20.6 br-Is6 45.5 br-bnu 55.2 gs-Ts6 19.2 f-an 13.9 f-an 16.6 i- i s3 27.1 f - an 23.0 f-an 23.9 gs-bm2 22.9 f-Ts3 32.3 i'-Ts3 <.8.5 an-Ts3 17.1 f-gs 46.8 f-Ts6 5 a. i s 6—bum. x\ % l. f-gs 41.0 f-biii2 41.1 f-Ts6 45.5 f - bm2 an-Ts3 20.8 an-Tf 3 13.3 -gs 27.2 an-'f s6 27.3 an-gs 30.3 an-bm2 36.5 an-Ts6 39.6 an - bm2 33.8 Ts3-gs 28.7 Ts3-bn2 31.2 gs-Ts6 30.2 bm2-Ts6 1.5 347 The data, as presented in the accompanying table indicate that Ts3 is between an and gs, and Ts6 near bm2 and to its left. The unsatisfactory nature of the data is well shown when arranged as 2-point tests involving an and either Ts3 or Ts6, as follows: T an + +Ts3 ++ anTs3 an+ Total 64 39 0 85 188 56 16 4 75 151 2X J± 78 170 Total 133 80 8 238 509 Total Ts3 = 191 ♦ non-Ts3 = 318 n an -= 246 , non-an = 263 + Ts6 an + +Ts6 ++ anTs6 an+ Total 77 80 13 65 235 24 16 9 18 67 112 _61 28 63 271 Total 213 159 50 151 573 Total Ts6 = 263, non-Ts.6 = 310 m an = 201, non-an = 372 In the cultures involving Ts6. an was strikingly and Ts6 somewhat aeficient. In the Ts3 cultures, an was slightly and Ts3 decidedly deficient. The striking feature of these records, however, is the discrepancy between complementary crossover classes, ++ to an Ts6 being over 3 to 1 and ++ to an Ts3 10 to 1. It seems likely that some, perhaps many, plants recorded as +Ts6 may have been an Ts6. The tassels were not removed and in many cases, ears failed to develop, and it is difficult to determine an from the tassels alone of Ts6 plants. V/ith Ts3 and an, experience of some years has led me to Question whether there may be an inhibiting effect such that, when heterozygous Ts3 and homozygous an are together, both characters generally fail to develop. But no adequate test of such a notion has been attempted. The locus of vestigial - k 5-point test of Vg with br f an bm2 has given the following results from the F]_ genotype -f Vg + + + br + f an bm2 348 0 1 2 _J _ -A. 1=A 1=A Total 164 5 1 42 103 4 2 1 15 337 Per cents of recombination are as follows: b£-Vg 3.3, br-f 3.9, br-an 19.6, br-bm2 44-8, Vg-f 0.6, Vg-an 18.4, V£~bm2 44-8, f-an 18.1, f-bm2 45.1, an-bm2 35.9 Sprague (Jour. Heredity 20: 143-145, 1939) has shorn that Vg_ is between hr and f., a locus supported by the data presented here. I cannot, however, agree with his sug- gested order of f Vgbr bm2. His three-point test, involving a very short region with a very long one, is unsatisfactory as pointed out by him, but the data as reported suggest the order br Vg bm2. His four-point test, again involving a very long region with very short ones, as a whole indicates the order suggested by him, but, when bm2 is disregarded, the resulting three-point data are + Vg + br.+ f -JL _L_ _2_ 1^2 Total 53 2 6 0 61 These data, obviously, afford no evidence of the order of the genes except that Vg. is between br and f . 5. Tests of knotted, perhaps involving an inversion - Bryan (N.L. 1938, p. $) reported Kn in this relation: br 7.2 f 27.0 Kn 24.1 Dm2. Uy last year's report (N.L. 1940, p. 17) was: an 22.5 Kn 23.2 Bm2 and an 22.6 Kn 9.6 gs. These 1940 reports were condensed from five-point tests including also br and f . In the five-point records given here those reported last year are combined with those obtained last summer. 349 Tests involving Kn + br + : br + : br f + : f + : f Regions + an + : an + : an Kn : + Kn : + Kn : + + gs + : bm2 0 82 140 107 1 4 4 2 3 3 23 46 44 4 6 39 1-2 7 2 1-3 1 1 1-4 2 2-3 1 3-4 1 19 1-2-3 4 1 1-2-4 1 __2 Total 133 256 151 br-f 12.8 br-f 4.7 br-f 0 br-an 6.8 br-an 2.7 br-an 0 Per cent br-Kn 26.3 br-Kn 28.1 br-Kn 29.1 Recom- br-gs 30.8 br-bm2 35.9 f-an 0 bination f-an 12.0 f-an 2.0 f-Kn 29.1 f-Kn 27.1 f-Kn 27.3 an-Kn 29.1 f-gs 30.1 f-bm2 35.1 an-Kn 22.$ an-Kn 26.2 an-gs 27.1 an-bm2 35.5 Kn-gs 6.0 Kn-bm2 24.2 It is obvious from these records that Kn is between an and £s and relatively near the latter. The recombination percentages for regions to the right of an are about those usually observed, but those in regions between br and an are far from normal. These differences in the two regions to either side of an are seen more readily perhaps v.hen the data are assembled as three-point tests:- + Kn + 0 1 2 1-2 Total an + gs 96 29 7 1 133 21.8$£ 5.3$ 0.8)1 + Kn + 146 L I 256an bm2 18. A% 113.$% 20 7. S%^ + + + i br f an 507 1/C. 4 17 540 2.2% 0.1% 3.1% 350 The data of the br-f-an array might indicate that the order of genes is not that given here. But the only order suggested by these data, on the basis of the usual criteria of three-point tests, is br-an-f. Since the chromosome-1 tester stocks employed in these tests are the same ones used in other tests (sections 1 and 2 of this report), no such assumption is tenable. It seems more likely that we are here dealing with a heterozygous inversion involving much of the region from br to an. This assumption is supported by the marked reduction in observed percentage of recombination, particularly in the f-an region, and by the appearance of more double crossovers than of singles in either region. Tests of miscellaneous genes with chromosome-1 markers - Twelve genes, whose linkage had not been previously determined, have been tested with several chromosome-1 markers. Tests of some of these were reported last year (N. L. 1940, p. 18) with only one clear indication of linkage, namely, bm2 with vl9. The data given in the accompanying table were obtained from F2 cultures of last summer. Percentages of recombination have been calculated with the help of Immer's tables. Many of the relatively large deviations from 50 per cent are not statistically significant. Percentages that show significant deviations from 50, or deviations on the border line of significance, are accompanied by their res- pective probable errors. The tests of this year are inadequate for much of the short arm of chromosome 1, since, except for sr, the markers used are all in the long arm. The frequency arrays for bm2 and vl9 from last year's report and from records of last summer are: + bm2 ++ bm2+ + +vl9 bm2 vl9 Total vl9 L. 1940, p.19 42 25 21 0 88 New cultures 60 44 12 6 -141 Total 102 67 58 6 233 Recombination percentage = 16 ± 4.3 It seems clear that vl9 is in chromosome 1. Attempted tests with &s have failed. It is not known, therefore, whether v!9 is to the left or the right of bm2. 351 Tests of non-linked genes Chromosome-1 markers New genes sr msl7 br f an £s bm2 at 58 - 49 54 52 43 42 bm3 50 - 57 4.8 57 41 _ g2 51 - 40 46 46 36+4.$ 34+3.7 ms5 60+ - 38±4.2 47 37 41 53 ms6 55 - 41 41 34+5.9 35 42* ms9 36 - 32+7.1 - — _ mslO - - 47 37+4-9 44 52 msl3 53 - 46 49 49 60+ msl4 - - 41+4•2 41+4•2 40±4.3 49 _ na2 48 55 - - 38 40 yg3 46 - 47 47 38 38 vl9 42 D 44 55 38 23+5.3 *vl9 — 52 58 51 <19 From N . L. 1940, p. 18 R. A. Emerson 1. Some additional data on chromosome VII. Field counts. (a) + + + v5 ra v5 ra glgl A 0 1 2 1 5c 2 Total 686 52 41 3 782 6.7% 5.2% (b) ♦ + + ra gl ra gl ijij X 0 1 2 1 & 2 Total 169 10 35 4 218 4 .6/£ 16.1$ 1 .3$ (a) v5 7 ra 6 gl (b) ra 6 gl 18 i.i 352 (c) Antherless (at), unlinked, is very clear cut and gives sharp classifications in the field. An F2 involving at, v5, and ra. showed at to be independent of the other two genes. (d) In making notes on v5, it is best not to wait until toward the close of the growing season. A number of plants often develop stripes only on the lowest leaves. These should be marked, since if seasonal or soil conditions are adverse, the lower leaves may die and such plants will be classed as green. A. C. Fraser (a) Any virescent-1 stock coming from the Co-op or from me must be used cautiously; there seems to ba another virescent mixed in. Can anyone send me a stock known to be vl? (b) In a backcross of about -400 seedlings the alien virescent mentioned above showed no linkage with wx. Of the 182 virescents in this backcross, 108 of them showed normal green stripes. This is suspiciously close to a 9:7 ratio. (c) A number of chlorophyll types (£, w, 1 and v) are being inbred by repeated backcrossing to the same inbred. The purpose is to get genetically uniform types for physiological study. Seed of the various types (twice backcrossed) are available to any one desiring it. (d) In connection with the aoove mentioned inbreeding program, I should like very much to obtain seeds of two or three different pale greens (esp. lethal ones) and of any other green seedlings that die. Will several of you who have such stocks send in a few seeds, please? (e) Can anyone send me some £3 seed? That in the Co-op seems not to carry £ at all. (f) A summary table of all my slit blade cultures is given below to show some of the abnormal ratios obtained. The division of the cultures into groups is arbitrary and hard to justify except on the grounds of convenience. Note that both B.C. & F2 totals show too many j3b plants. 353 Sb sb Ratio Sum of B.C. 495 384 1.29:1 Sum of F2 3083 1001 3.08:1 (less than 4:1) Sum of F2 2138 458 4.67:1 4:1-7:1 Sum of F2 (greater than 7:1) 6 33 69 9.2:1 Sum of all F2 5854 1528 3.83:1 (g) Small F2 »s last summer showed no linkage of bm3 or wa to sh, wx, or gl4; nor of sb to lg2, Ts5, j, sh, wxj £14 or £l. Several attempts have failed to show~any linkage of my g!4 to yg, sh, or wx. (This is not the glk of Burnham.) John Shafer Cornell University and the United States Department of Agriculture 1. Trisomic stocks. An effort was made during the summer of 1940 to assemble a set of all the known trisomic stocks, to produce stocks of those which were missing, and to make appropriate crosses to build up reserve stocks of all of the trisomes for the future use of cooperators. It was found that seed was available of all of the trisomes except one and four. Individual trisomic plants lacking B chromosomes were selected by actual chromosome counts in each of the eight available stocks. Genetic tester stocks were also examined cygologically in an effort to get together two complete sets of testers lacking B chromosomes, each set to have different endosperm or seedling genes with one good gene in each chromosome. These two sets of testers to be used for crossing alternately with the different trisomic stocks in order to maintain vigorous, genetically identifi- able trisomic stocks for general use. Unfortunately, several of the present trisomic stocks are very much lacking in vigor and uniformity and are segregating for various lethals, with the result that although we started the season with five or more trisomic seedlings in each of the eight stocks, at 354 the end of the season v/e had not more than one or two poor trisomic ears from two or three of the stocks. But from the other trisomic stocks we have anywhere from 3 to 10 good trisomic ears. It is especially important in working with trisomic plants to have vigorous, uniform stocks. A number of the trisomic types are inherently weak. In fact the trisomic plants in most of the trisomic stocks apparently come chiefly from the smaller seeds and are apt to be weaker than theii disomic sibs in the seedling stage\ at least it was our experience that from 7$ to 90 percent of the smallest seeds from trisomic ears of the 8 different trisomics v/e worked v;ith produced trisomic individuals. It would be highly desirable also to maintain a high degree of uniformity of plant type in the trisomic stocks in order to be able to pick as many as possible of the trisomic individuals on the basis of their phenotypic appearance. As an experiment in this direction, we crossed a number of different trisomic plants with pollen of several different inbreds which were known to contain no B chromosomes to see what the trisomics would look like in the various F-j populations. In our cultures last summer v:e could, with reasonable accuracy, distinguish the trisomic plants from their disomic sibs in our stocks of numbers 5, 8, and 9, with indications that at least several others could be detected phenotypically in more uniform material. Another procedure for obtaining very uniform trisomic stocks is to isolate the various trisomes from the selfed progeny of triploids obtained by intercrossing diploids and tetraploids derived from a common inbred parent. In attempting to do this we have learned from experience that it is advisable to start v/ith a very vigorous inbred; otherwise the triploid progenies from which the trisomes must be isolated are rather weak and not too satisfactory to work with. It is expected that the two missing trisomes, numbers one and four, will be available for distribution next year. Selfed ears showing trisomic ratios for su and similar material segregating for bm2 were obtained last summer from individual plants in triploid progenies known from chromosome counts to have from one to three extra A chromosomes. Technical assistance for much of the routine cytolo- gical work in connection with these trisomic stocks was furnished by the Maize Cooperation. Genetics of the B chromosomes and their derivatives. The B chromosomes are by no means genetically impotent as was iormerly believed and is still being reiterated in current literature on maize cytogenetics. It is true that in small 355 numbers they appe-ar to produce no discernible effects; they are transmitted more readily than any known A chromosome fragments through both pollen and egg and their presence in genetic stocks seems not to have interfered with genetic analysis of mendelizing characters. But this docs not necessarily mean that they are genetically inert or devoid of hereditary potentialities. In summarizing my data on the behavior of the B chromosomes that have been accumulated over a period of years in attempts to solve the enigma of their origin and fundamental nature, there arc some rather interesting conclusions that can be drawn with reasonable assurance that they may mean something. Although individual plants with relatively few B chromosomes are indistinguishable from their no B sibs, higher numbers of B chromosomes produce marked effects: More than 13-15 cause some reduction in fertility; more than 23-25 cause a marked reduction in both fertility and vigor; more than 30 occur rarely and the plants are very weak, produce mostly aborted pollen and set little or no seed. In reciprocal crosses of plants with 1 B x 0 B, the B chromosome is transmitted about equally well by the pollen and egg to about one-third of the progeny. Excep- tional plants with 2 or more Ds appear in these crosses more frequently when ttu B is carried by the pollen parent. Reciprocal crosses involving 2, 3, and k Bs with no B plants ar^ markedly dissimilar: when the 3s are carried by the seed parent, the numbers in the progeny tend to be intermediate between the parental numbers, but when they art. carried by the pollen, the 0 B, 2 B and k B classes are predominant. This was true of both meiotic and somatic counts, the total number of individuals involved in these crosses being 398. The B chromosome plants do not breed true for any given number of B chromosomes, regardless of whether the number is odd or even, k'hen selfed, or when plants with the same number of Bs are sib crossed, less than one-third of the progeny have the parental number of B chromosomes. Various numbers are represented in the populations, the mean number being approximately the same or slightly less than the parental number for plants with from 1 to 17 B chromosomes. The total number of plants studied in these selfed and sib-crossed progenies was 988. Numbers higher than either parent appeared frequently in crosses between plants with different numbers of Bs ranging from 1 to 20, but in the progenies of plants with more than 20 Bs they appeared less frequently. The mean 356 number of Bs in the progenies of plants with from 1 to 10 Bs when intercrossed was essentially the same as the mean parental number; with higher parental numbers whose means ranged from 11 to 20.5 the mean number in the progeny was less than the parental mean by from 10 to 30 percent. These data were from 65 cultures which included a total of 983 plants. Irregular assortment in meiosis, somatic nondisjunction and double division in somatic mitosis possibly due to irregular timing of centromere division, are some of the characteristics of B chromosome behavior responsible for the extreme variation in number observed in the progenies of B chromosome plants. Although the number of 3s in an individual plant is not necessarily the product of the con- tributing gametic numbers since changes in number may occur in outogency due to mitotic irregularities there is little evidence of selective elimination of gametes except among very high B chromosome plants. There is no evidence from these experiments on the breeding behavior of the 3s to support the contention of Darlington, presented in a recent discussion of "the activity of the inert chromosomes" (sic) in maize, that there exists a population pressure maintaining an equilibrium distribution of the B chromosomes at relatively low levels in different stocks. In fact the results suggest that higher numbers than are present in most natural popu- lations would readily be tolerated. It seems suite possible that the B chromosomes are on the increase in at least some varieties of maize. No disturbed ratios were obtained from Fp ana backcross data involving B chromosome stocks crossed with 43 known genes distributed throughout the 10 linkage groups. The linkage relations of these genes are indicated on the accompanying map in which the tested genes are underscored. This map also includes tentative assignments of centromere positions based on information kindly furnished by Anderson, Rhoades and Burnham, the more definitely placed centromeres being represented by an oval drawn with a solid line and those less definitely placed being similarly represented by a dotted line. Disturbea ratios have been obtained with the gene .sId, together with some evidence that the reduction in the number of recessives in the segregating progenies was proportional to the frequency of the B chromosomes. (See also Shafer’s discussion of s_b ratios in this News Letter) This would be expected if the B chromosomes carried the normal Sb allele. Unfortunately the linkage relations of s_b are unknown. These gene tests involving the B chromosomes have an important bearing on the fundamental question of the origin of the B chromosomes. If the centromere positions indicated on the linkage maps are even approximately correct, it is 357 apparent that the,tested genes giving undisturbed ratios in the presence of B chromosomes are distributed among 17 of the 20 normal A chromosome arms. Only 3 arms, the short arm of S and 10 and the long arm of 9, do not include at least one tested gene. If a test of one or a few genes were sufficient to exclude a particular chromosome arm from further consideration as the source of the B chromosome, the problem of the origin of the Bs would be much simplified, but in my opinion such tests would not be sufficient. It is altogether possible, in my opinion, that only part of a particular arm is represented in the B chromosome. For example, it might consist of an A chromosome centromere plus some adjacent euchromatin, but not necessarily all of the euchromatin of any particular arm, and in addition hetero- chromatin from the same or some other chromosome. This suggestion as to the possible mode of origin of the typical B chromosome may seem unnecessarily involved. However, there is a rapidly accumulating body of evidence that the chromo- some is not as stable a unit as it was once thought to be. In fact it is surprising that chromosomes maintain any individuality whatever as separate and distinct morphological entities for extended periods of time in the light of the numerous types of reorganization to which they are subject. Furthermore, the typical B chromosome has a distinctive prophase morphology unlike that of any one region of similar length among the A chromosomes ordinarily present in exist- ing types of maize. This is not an off-hand statement based on casual observation, but is the conclusion arrived at after making a very critical survey of the meiotic prophase morphology in well over fifty varieties of maize representing all of the known types of flour, flint, dent, pop and sweet corn, a survey that was conducted primarily to throw light on the origin of the B chromosomes. This does not mean that there may not be in existence today types of maize containing an A chromosome or segment thereof that is identical with the B chromosome. Or it may be that such a chromosome existed in primitive strains of maize that are no longer in existence. The fact that the B chromosome ordinarily does not synapse with any of the A chromosomes suggests that it is not of recent origin, but synaptic behavior alone should not be considered as proof of this assumption. There is the further possibility that hybridization with relatives of maize may have been involved in the origin of the Bs, but in my opinion the possibilities of a more direct mode of origin ar^ by no means exhausted. In a further sewarch for clu^s to the origin of the Bs, it would seem highly desirable to examine additional types of maize especially from regions where primitive stocks may still be in existence. Also more extensive tests of known genes should be made in the search for alleles of B 358 chromosome genes; possibly Sb is one such allele, but addi- tional cytological and genetical tests are needed to establish this. If the suggestion made above concerning the origin of the Bs is valid, and if there is a tendency in maize as in Drosophila for heterochromatic regions to be populated with fewer genes than are the euchromatic regions, the best chance of finding alleles of known genes in the B chromosome would be to test especially genes lying near the centromeres in the linkage maps. These genes may actually be an appreciable distance cytologically from the centromeres. But if the proximal euchromatic region of the B is in approx- imately the same relative position with reference to the centromere that it was in the A chromosome from which it originated, some of these nearby genes should be represented by alleles in the euchromatin of the B, which constitutes approximately one-third of the total length of the chromosome. A certain number of these nearby genes have already been tested as indicated on the linkage map. An especially good test involved chromosome 5 in which Rhoades* data from his telocentric fragment has given us the best evidence we have of the location of a particular centromere relative to neighboring genes. His evidence tells us that the closely linked genes, bm and _bt, are definitely on opposite sides of the centromere. These two genes, as well as a2 in the short arm and bm, jar and v2 in the long arm of this chromosome gave normal backcross and ?2 ratios in the presence of B chromosomes. Thus these tests would seem to exclude the possibility that the regions in which they are located arc involved in the makeup of the B chromosome. A notable characteristic of the 3 chromosomes is that they are like the a chromosomes in being susceptible to breakage, with the resultant loss of acentric segments of chromatin or rearrangement of parts. But there is this distinction that the supernumerary B chromosomes can undergo a greater variety of such morphological changes than can the A chromosomes without deleterious effects, and their monocentric derivatives can be readily maintained in culture for further study. Over a period of years a considerable number of such B chromosome derivatives have arisen in my stocks, the first of these being the C chromosome that was described back in 1928. Since most of the-se elements have been detected in root tip figures being examined for chromosome count, they have been grouped for convenience in four reasonably distinct size- classes or types, based on their appearance in the somatic metaphas^. These include (a), the C type that is somewhat shorter than the B chromosome but definitely elongated in contrast to (b), the D type that is essentially spherical with a diameter roughly equivalent to the diameter of an ordinary chromosome, (c), the E type that is of approximately the same size as the undivided satellite of chromosome 6, and (d), the F type that is distinctly smaller than the E type and in fact is 359 only slightly above the lower limit of visibility of the photomicroscope. On the basis of this classification there can be no additional new types of still smaller B chromosome deriva- tives, at least not until the electron microscope is utilized in the study of chromosomes. (Incidentally, this series of chromosome types from B to F, if interpreted in the reverse order, makes a very convincing demonstration of the de novo origin of chromosomes.) In the meiotic prophase morpholo- gical distinctions within these size groups can be detected and may be classified accordingly. The B chromosome derivatives are proving very useful in studies of the relative genetic potency of different parts of the B chromosome. Data are available at the present time which suggest that the sterility-inducing effects of the B chromosome are to be attributed to factors localized chiefly in the proximal euchromatic region of the chromosome. There is some evidence that other mutant derivatives of the typical B chromosome, such as extensions of the long arm or additions to the rudimentary short arm, occur from time to time, but these are less easily defected in somatic figures because of their greater similarity to the shorter A chromosomes. The occurrence of distinctly dibranchial B type chromosomes in maize has been described from somatic figures by Darlington and others in recent years. But in these cases the position of the centromere has very probably been misinterpreted. The typical B chromosome when viewed in somatic metaphas^s often exhibits what appears to be a subterminal constriction, especially after fixation with fluids that shrink the chromosomes. This is not a true centric constriction but is actually the weakly chromatic region between the proximal knob adjoining the centromere and the distal heterochromatic portion of the chromosome. This interpretation is quite obvious if one is familiar with the pachytene structure of the B chromosome and follows the transformation accompanying the shortening of the B chromosome during the late prophase and early metaphase of the first microspore division where the distinction between euchromatin and heterochromatin in these stages is clearly apparent in good preparations. Many pachytene figures of the typical B chromosome do, however, show the presence of a rudimentary short arm consisting of a very few small chro- mosomes. This arm is often folded back against the proximal knob on the opposite side of the centromere, thus making the centromere appear truly terminal. L. F. Randolph 360 - 28 - M A I Z E L I N K A G E M A P S WITH TENTATIVE ASSIGNMENTS OF CENTROMERE POSITIONS sr msi 7 tsp P zl — br f an gs I —i---%---------1— i-------f—0 25 30 53 ' 80 85 102 129 VB3 iS gig B sk fl ts £4 Ch 2 -I---*------- *- -+— o -I—0 11 30 4S 56 68 74 83 128 cr *g ts4 _bn rm 3 — *— W _)— (— 18 40 47 64 103 de sp su de16 zD6 Tu ̂ gl 4 0 - + - o - « C ) ' '56 66 71 74 84 100 105 111 ft- bm bt y_ bv pr ys -vV, 5 4 - 4 0 ^ - ^ -»- —*- 0 6 7 1C 12 31 40 72 po Y PI 80S 21 6 0 13 41 51 61 in I 5 £5 S i TP LI 3 n bd — t----0 ~ i y-i---- 1— I----------1------------------- - ► 7 0 4 18 22 32 38 56 92 v16 2le J 8 0 14 28 knob yg C _sh bp wx v 9 0« — H----*--- -KD— *- 0 2 21 24 3S 54 66 Rp °g pp. li 1P e R d7 10 (-'■ Sv- t i 0 16 27 28 38 43 57 84 361 Illinois Agricultural Experiment station, Urbana, Illinois In further studies on genes h (starchy endosperm) and fl2 (floury endosperm), h was found to be hypostatic to sul an the recombination values bringP-30-£a 34 br. It ditfers from sp and sp2 in that pollen carrying it is for the most parTcLevoicTof starch. Cytological examination shows no visible deficiency in chromosome 1 . C . R . Burnham The following chromosome map shows the loci of those interchanges for which there is cytological information. It is based on data presented in previous Coop Letters, whatever has been published and in addition unpublished data of Dr. C. R. Burnham. The scheme Anderson has used is followed, the breakage points being measured from the spindle fiber insertion region in tenths of the length of the particular arm in which the break occurred. Inter- changes for v/hich only genetic information is available are not listed. As is customary, the map presents the cytological lengths of the chromosome which are in proportion, using chromosome 10 as 100 units. The length of each arm is given at the spindle fiber attachment region, the total chromosome length being the total of the two arm lengths. The long arm/short arm ratio is given at the bottom of the map. 366 The following example illustrates the use of the map: translocation l-2a is listed as 2a on chromosome 1 opposite .7 on the long arm; on chromosome 2 it is listed as la opposite the locus .6 on the long arm. I/hen more than one break has occurred at the same point, they are grouped together. For example, there are 5 translocations at locus .3 on the long arm of chromosome 2. Breaks which have occurred in the satellite of chromosome 6 are grouped in that region but their position in the satellite arm is not definitely known. 6-9a occurred in the nucleolus- organizer region. 2-6a and 5-9a involved the short arm of chromosome 6, but their relation to the spindle fiber insertion region is not known, hence they are given 0+ ratings. On completing this map Dr. C. H. Burnham has given advice and suggestions and a final check on the figures. References: Anderson, Maize Coop Letter, March 3, 1940 " 11 '♦ " , April 13, 1939 " " » « , March 6, 1938 " " » " , March 4, 1936 " " '* " , March 6, 1935 ” Genetics 23: 307-, 1938 M « 24: 385-, 1939 and Brink, Genetics 25: 299-, 1940 Clarke and Anderson, 1934 Emerson, Maize Coop Letter, March 5, 1940 " " " " , March 23, 1937 Burnham and Cartledge, Journ, Arner. Soc. Agron. 31: 924-, 1939 Edward Garber 367 - 3 5 - M A I 2 X C H R O M O S O M E M A P S with locations of cytologically placed translocations 2 3a - * 9 3c |.7 9c .-*6 6b -.75 9 a • • • 7 6b .-.8 lb h . 6 3c’) 7bJ 2b *-.4 7a ...6 8 8a .-.5 1 Clb o 6c •■#3 2 « 3b 9 5b o 3a j.2 9a 6 5b ...4 | 8c i 7a - .2 I 9b j-.l 10b -.5 9b - ,2 8a 5c .-.1 5a -o+ 80.9 2a -1 o+ 102.7 59.7 66.5 84.6 15.1 38.8 35.0 40.7 27.8 126.3 115.1 119.3 V/ v 1 ̂ -- - ̂ ’ 81.3 72.2 T 8b) 5a - -, 1 .1 9a .. 1 *■a , 4a - 3a ••.1 3a 3b - r a • .1 i -8 .1|J- lc\ 7b - .2 .2 5dl 3b 10a -.2 la . -.2 24.2 6a _ 9a2c •■ .25 3a -.25 it! .3 7b --.25 10b 6 lb a2 5 - i -.3 8^ 4.4 3 7c 4 3 la\ 2d L 2 .4 lb — . 5 a -•.4 2e( 5al 7a 3c 2a - .6 8 -.5 10c10a a c - 3c « • 5 4a) 7 2b) 10a - . 6 9aJ“ •7 4a 3eJ .6 8 9a -.9 laY 8b 4b; *7|= , e 5a •>.7 6a — ► _7,b 7a — r! »oc 8a - - # 7I 18 10a - .79b 5a 3a 2a 7d -.8 a r m r a t i o s 1. 1 4. 22 3 2.00 1.63 1.07 7.10 2.60 3.00 2.00 2.60 368 University of Missouri, Columbia, Missouri, and Division of Cereal Crops and Diseases, U.S.D.A. Comparison of the Genetic Effects of Xrays and Ultra- violet Treatment. In 1939 and 1940 an attempt was made to determine the relative frequency of mutation and other types of genetic alteration induced by comparable doses of Xrays ana ultraviolet. Since there is no physical basis for equating doses of the two radiations, it is necessary to make the comparison on the basis of some biological equivalent, for example, to determine the effect upon mutation of two doses equal in inducing deficiencies or translocations. But since previous studies had sho\ n that the deficiencies and translocations induced by ultra- violet are of types different from those produced by Xrays (or include various types in widely different pro- portions), the doses equivalent on the basis of one chromosomal effect would be widely different from those equivalent on another. The doses used therefore were chosen arbitrarily at levels suited to the significant determination of mutation frequency, and their equivalence may be judged only by the frequencies of the various alterations detected. The Xray doses used are relatively low, so as to permit the survival of as many plants as possible and the production of well- filled ears, which is essential for the determination of mutation rates. The ultraviolet doses used are close to the tolerance limit for the wave lengths represented. Since both types of radiation produce defective plants of various kinds, it is essential to reduce losses to a minimum and to consider the individuals lost as well as the survivors in the interpretation of the results. The populations used represent the entire seed population from the treated ears, and special precautions were taken to secure maximum germination and survival. Plants which died early or which failed for other reasons to yield a pollen specimen were classified as M+M (apparently normal plants, accidentally lost) and ,,-f( (apparently defective plants) . The treatments compared, populations used, frequency of endosperm deficiency (A, Pr, Su), and losses to pollen shedding are shown below: 369 "Enad- sperm Lost Excluded defi- Embryo Un- Died No No. cien- abor- germi- Early Pollen Hap- Contam- Popu- Seeds cies tion nated + + — loid inated lation % X3022 210 43.1 19 12 10 8 0 0 2 0 159 12967 160 28.8 7 10 1 3 0 2 1 0 136 250 r 420 3.0 11 11 3 7 1 1 0 2 334 500 r 217 7.4 S 7 3 4 2 4 1 0 188 Control 10X6 0.3 8 9 20 1 0 1 2 0 975 Frequency of Pollen Segregation in Fq. In populations so laris' as tftfl'gfe TddJTOga TOE m e determination of mutation rates [particularly with low doses ana control progenies), it is not feasible to determine the frequency of deficiencies and translocations by the direct cytological examination of every plant. Some indications regarding the frequency of chromosomal derangements may be obtained from the frequency and type of pollen segregation in Fq. Pollen segregation was recorded as to percentage and type of defective pollen, the types ranging from "a” (significant reduction in size but normal development of contents) to T‘e,f (practically empty) . In the table which follows, types a and b are listed as "subnormal", types c, d, and e as "aborted," and segregations of both classes in the same individual as "mixed," The following facts determined from investigations in previous seasons are of help in the interpretation of the pollen records: (1) "Directed segregation" in maize translocations is absent or extremely rare. The plants with segregating defective pollen therefore include all of those in which translocation has occurred as well as those with deficiencies. (2) Gametophytic lethals at points of translocation are absent or very rare. If, as a result of "position-effect" or other causes, there were a tendency for mutational effects at the breakage points, it might be expressed by failure in development or functioning of the pollen carrying the translocation chromosomes. This does not occur. It is therefore possible to discriminate between segregating defective pollen due to translocation and that due to deficiency by transmission tests. 370 (3) F^ plants with segregating defective pollen include many with cytologically detectable deficiencies not associated with translocation. Among pollen segregating plants from Xray treatment, these deficiencies include some which are obviously intercalary. Most of the cytologically detectable deficiencies are found in plants with "aborted1 pollen, but in short intercalary deficiencies defective pollen is frequently of the "subnormal" class. The deficiencies from UV observed cytologically include none which is clearly intercalary. In all of the UV deficiencies so far observed cytologically the segregating pollen is of the "aborted" type. (4) Among the plants with segregating defective pollen, the proportion due to translocation is much lower with ultra- violet than with Xrays. With high doses of ultraviolet, translocations unquestionably are induced, but the great majority of these are "deficiency-translocations"; that is, plants in which one or both of the chromosomes involved in the translocation has lost a segment. These deficiency- translocations are usually very defective plants, and their frequency depends in large part upon the precautions taken to insure survival of the poorest plants of the progeny. Translocations of this type may not be detected by trans- mission tests; they may be identified only by direct cytological examination of the Fj. The frequency of segregating defective pollen in these cultures is listed in the next table. The numbers and percentages given in parentheses represent the frequencies when each "high-sterile" is taken to represent two segregating factors for sterility. No. Semi-sterile High-sterile Low Exam. Sub.Ab. Mix. Sub. Ab.Mix. Sterile Total % X3022 159 10 15 1 0 2 3 1 32(37) 20.1(23.3) X2967 136 13 8 0 1 2 1 2 27(31) 19.9(22.8) 250 r 384 13 23 2 0 8 2 1 49(59) 12.8(15.4) 500 r 188 9 21 6 0 12 6 5 59(77) 31.4(41.0) Control 975 3 A 0 0 0 0 2 9(9) 0.9(0.9) Low Deficiency Rate in Embryo vs. Endosoerm with UV. In both UV progenies the frequency of plants with segregating defective pollen was about 20 per cent. There is reason to believe that many of these are due to causes other than deficiency (notably to mutations producing subnormal pollen), But even if all were due to deficiency, their frequency is 371 far lower than would be anticipated from the endosperm deficiency rates. The seeds planted showed endosperm de- ficiencies amounting to about 36 per cent for the marker genes A, £r, and Su; these could represent only a small fraction of the deficiencies present in the entire ten chromosomes of the treated gamete. With equal deficiency frequency in the embryo, almost all of the Fq plants should have segregating defective pollen due to deficiency, and many should have several deficiencies. At one marked locus, a direct comparison may be made. The seeds planted in the two UV progenies included 71 endosperm deficiencies for A; the Fq plants included no A- deficiencies. Although induced deficiencies are relatively rare in the Fq embryos, it is certain that they are not wholly absent. The treated pollen carried the dominant markers A 5 2rj the UV families included five genetically marked deficiencies and several unmarked deficiencies which were identified cytologically in defective plants. Only one deficiency (a monosomic for chromosome #6) was found in the much larger control population. Frequency of Translocation. In certain cultures, translocation frequency was determined by direct cytological examination of the Fq plants in every plant with segregating defective pollen. The cultures examined included the entire population given the ultraviolet treatment ,:X2967M and the entire population from one ear given the Xray dose M250 r” and one ear given ”500 r.” The results are shown below: Diakinesis Segregating Pollen Association Semi- High- Low- Population Sterile Sterile Sterile change Associ X2967 136 21 4 2 0 3 250 r 97 14 0 0 4 2 500 r 83 20 7 3 11 6 It is noteworthy that deficiency-associations are found with Xray as well as UV treatment, but in the former they occur with a larger number of interchange-associations, while with the latter they do not. Frequency of Translocation in Control. The spontaneous frequency of translocation is of interest in determining whether the occurrence of chromosome interchanges following 372 ultraviolet treatment is an effect of the treatment. Among the translocations observed in UV-treated progenies to date, although as previously mentioned the majority are deficiency-translocations, there are two or possibly three which appear to be regular segmental interchanges. Although such translocations have previously been found in untreated maize populations, there is no basis for an estimate of their spontaneous frequency. The large control in this experiment included only nine plants with segregating defective pollen; the progeny tests from these showed that two of them transmitted through pollen the factor for aborted pollen segregation. Diakinesis examination in these progenies showed in both cases the presence of chromosome interchange producing a ring-of-four at diakinesis. The spontaneous frequency of chromosome interchange thus appears to be appreciable, and the number of interchanges observed following ultraviolet treatment is not significantly higher than that in untreated material. The results suggest that UV treatments produce a significant increase in the frequency of deficiency-trans- locations, without appreciable effect upon the frequency of segmental interchanges. Mutation. The mutations determined were those involving endosperm characters, defective seeds, germless, and seedling abnormalities. Each of these types may be determined by examination of the selfed ears of the F2 plants or of the 100-seedling progenies grown from each of these ears. All of the mutations which are not clear-cut and unmistakable in the ?2 culture are checked for recovery in F3 from hetero- zygous F2 plants. The analysis of the check-progenies of 1940 is not yet completed, and the data therefore are given separately for number of mutations and number of doubtful mutations, the latter being those subject to the F3 check. The percentages in the table are provisional percentages representing the clear-cut mutations plus half the doubtful mutations. Confirmation tests so far completed indicate that the final percentages will be somewhat higher than those here given. Endosperm Germless Seedling n M M? % n M M? % n M M? % Total % X3022 62 5 5 12 .1 110 2 11 6.8 107 11 2 11 .2 30.1 X2967 93 4 8 8.6 82 0 6 3.7 81 4 1 5.6 17.9 2$0 r 250 1 2 0.8 298 0 1 0.2 299 1 2 0.7 1.7 500 r 143 5 7 5.2 133 1 2 1.5 126 1 1 1 .2 7.9 Control 613 0 7 0.6 766 0 1 0 .1 764 1 2 0.3 1.0 373 The mutations included, together with many useless types, a scattering of promising viable mutants affecting endosperm and seedling characters. The number of mutants is consider- ably larger than that shown in the table, since several other treatments were handled similarly. In all of these the F2 ears which yield the mutations are segregating for Y and PI, permitting a three-point test for chromosome 6 mutants, and are segregating also for single markers on chromosome 2, 3, 4, 5, 9, and 10. Doctor C. R. Burnham is undertaking the location of some of the more promising mutants. Comparative Mutation Rate from Xray and UV. As the table indicates, mutations were considerably more frequent from UV than from Xrays, in spite of the fact that the Xray doses used produced considerably more translocations and probably more deficiencies. Actually the mutation rate from UV is considerably higher than is indicated by these data. Among a sample of pollen grains treated with UV, because of the high absorption in passing through the pollen grain contents, only a small proportion receive a heavy dose at the site of the gametic nucleus, and many receive no effective dose at all. The mutation rate among the effectively-treated pollen grains therefore is much higher. Many of these include two or more independent mutations. It is probable also that many of the segregating pollen defects (particularly of the subnormal class) are due to mutation expressed in the gametophyte generation rather than to deficiency. Since intercalary deficiencies are so rare and mutations are so common with UV treatment, it seems probable that the high frequency of subnormal pollen segre- gation following UV treatment is largely or wholly the result of gametophytic mutations, and is another expression of the high frequency of mutation induced by this agent. Technic for Identification of Gametophytic Mutations. In the mutation technic used in the experiment just described, gametophytic mutations are not detected if they have no visible effect upon pollen development; and if they produce defective pollen, they are not distinguishable from short deficiencies. Another difficulty is that many of the sporophytic mutations are questionable because of possible over-lapping of the normal phenotype. Both of these difficulties may be avoidable, for limited chromosome regions, by the use of inversions to inhibit crossing-over. A trial of this method with one inversion was made in 1940, in an experiment comparing UV and Xray treatments in a manner otherwise similar to that of the experi- ment just described. The method may be used more effectively with a combination of inversions in various chromosomes. 374 The treated parent was I wx: the untreated parent carried r3arrangement-9 (McClintock 1939; with i 17x. This rearrange- ment eliminates crossovers in a large part of chromosome 9. The seeds therefore are of three types — one fourth I wx, homozygous for the treated normal chromosome; one fourth A homozygous for the untreated chromosome; and one half A heterozygous for the treated and untreated chromosomes. Induced chromosome 9 alterations are linked with I wx. They are manifested in three ways: (1) By pollen defects linked with wx. In iodine-stained pollen specimens extremely slight effects on pollen size or development may be recognized, far below the limit of detection in unlinked segregation. (2) By modified ratios for A and Wx. C-ametophyte mutations or deficiencies without visible effect on pollen development, if they prevent functioning of pollen, modify the 3:1 ratios to 2:2 and 4:0 respectively. If they permit reduced functioning, they permit the segregation of a reduced proportion of wx seeds. (A reduced proportion of wx seeds may result also from a Ga-mutation inhibiting functioning if separated from the rearrangement by crossing- over .) (3) By seed and seedling mutations linked with I Wx. Here also the linkage permits the detection of some mutants which would be doubtful or undetectable vdthout linkage. The mutants are crossed with C Wx (normal chromosome) for genetic location in three-point tests. Gametophyte mutations not transmitted through pollen may be recovered from the heterozygous A LA seeds, and when pollinated by C Wx (normal) yield heterozygotes in which the location of the Ga-factor may be determined by crossing on C wx or c wx. Deficiencies and other chromosomal alterations not lethal to the female gametophyte may be recovered similarly, for cytological examination in plants free from the rearrangement. The spontaneous frequency of the various types of alteration is shown in the same ?2 ears by segregations of the same kinds linked with A Wx instead of I wx. The results of this experiment, as regards chromosomes other than #9, were similar to those of the previous experi- ment, except for differences incidental to the use of different wave lengths and dosages, which will not be discussed here. 375 The number of chromosome 9 alterations of each type identified is shown below: Treated Chromosome-9 UV UV Xray Untreated X2967 a2537 600 r Chromosome-9 Population 457 263 288 1008 (1 ) Defective Pollen Aborted 2 0 3 0 Subnormal 0 0 2 0 Total 2 0 5 0 (2) Low Transmiss ion 12 4 2 0 (Pollen Norma 1 ) (3) Mutation Endosperm 3 2 0 0 Germless 1 0 0 0 Seedling 2 2 1 1 Total 6 5 1 1 These constitute a representative sample of the genetic alterations induced by Xrays and UV, all located within a region well suited for critical comparison genetically and cytologically. Qualitative Comparison of Induced Mutations. The very high frequency of UV mutations, with the much lowered frequency of chromosomal derangements, suggests that these may include types of mutation not included among the Xray mutants, and may be relatively free from the various sorts of pseudo-mutation v/hich occur under Xray treatment as by- products of induced chromosomal derangement. The problem is to find criteria which may be applied to distinguish types of "mutation.” Possible criteria available in maize include the following: (1) Gametophyte viability. Many induced mutations are of lowered viability in the gametophyte, particularly as shown by reduced transmission through male germ cells. Differences in viability among mutants are usually regarded as characteristic of the different mutant alleles, the higher viability of standard alleles being considered the result of natural selection. This view is contradicted by results with the known spontaneous mutations in maize. A large number of mutants representing various endosperm genes is available, and in 376 - UK - these gametophyte viability and male transmission arc regularly normal. This suggests that the low viability of induced mutants may be due to the loss of something more than the dominant allele which is assumed to have mutated. Transmission of the mutant through pollen, in competition with the normal non-mutant pollen grains, provides a very rigorous test of gametophyte viability, which may be applied to mutations at any locus. (2) Use of genes which mutate normally to an intermediate allele. Spontaneous mutations of H^, identified by colorless seeds, are regularly mutations to small rr, as previously reported. Recent studies have shown that Rr mutates also, and with comparable high frequency, to It does not mutate spontaneously, or at most does so very rarely, to rS„ This may mean that the effect of Rr on anthocyanin coloration of the aleurone and of the plant is due to two separate but very closely linked genes, but whether this is true or not, the fact provides a convenient method for distinguishing between spontaneous mutations at this locus and the type of pseudo- mutation which could result from haplo-viable deficiencies. A similar situation may apply at certain other loci. Recent trials show that the gene A^ also mutates spontaneously, with a fairly high frequency, to an intermediate allele. The results of an experiment in which the suspected mutations were identified by loss of aleurone color and all were subsequently checked by progeny tests show the following frequencies: Stock Mutation to aP Mutation to .a Ab Ab 0/55,765 25/36,661 A A 0/19,587 0/9,431 The a^ mutants, when combined with the appropriate complementary genes, have the red-brown plant color and brown pericarp characteristic of the standard ap, although some of the mutants show a somewhat deeper color in aleurone and plant than the standard. Nine of these mutants have been tested for dominance of the brown pericarp effect. In all of these the effect is dominant as in the standard ap . (3) Reverse mutability. The analysis of the action of Dtby Rhoades makes possible the effective application of this criterion in the case of apparent mutations to a. 377 It is not applicable to the aP mutations from A1̂ since Dt is without effect on a-P, Whether it is applicable to all mutant a's, or to the colorless mutations from all A rs, also remains to be seen, since the present stocks of a, on which Dt is effective, trace to not more than two original sources. Reversability of a mutant a under the influence of Dt is good evidence against deficiency, but failure of a mutant to be reverted by Dt is not convincing evidence against intragenic mutation. (4) Detailed analysis of phenotypic effect. In the case of the genes affecting anthocyanin pigmentation, mutant pheno- types may be compared quite precisely by the use of methods developed by Karrer, Robinson, Scott-Moncrieff, and others for the identification of the various anthocyanin pigments. A study of the anthocyanin pigments in maize now being made by J. E. McClary indicates that there is a very rich variety of these pigments in maize, including several which do not commonly occur among the flower pigments genetically studied by the English workers. One of these is the anthocyanin pigment which occurs together with a flavoncl in the aP stock. In the presence of 3 and PI, A b, like A, produces chrysanthemin, but a.P produces an anthocyanin of distinctly different properties. The dark &p obtained by mutation from apparently produces the same pigment in larger quantity. Comparison of Xray and UV Induced mutations of a . Mutations and deficiencies involving the A locus may be iden- tified by seedling examination of Fp plants from the cross a x A B PI Rr. a very large number of plants of this constitution have been examined following treatment of the male parent with Xrays, and the green seedlings saved for identification of the mutation or deficiency. The majority of such plants turn out to be distinctly defective in growth and to have segregating aborted pollen, a small proportion approximate normal growth, but these also have defective pollen. Among them a few are found with segregating pollen of the subnormal type. Two plants were found in which the A effect had been lost, the plant was of normal vigor, and the pollen was completely normal in appearance. Both plants had the phenotypic appearance of typical a B Pi, They are designated a*4 and yX°. In addition one plant cf a B PI phenotype ana normal vigor, but with segregating subnormal pollen, was included in the further tests. It is designated „X1 378 In similar progenies of plants from UV treated pollen, the frequency of loss of the A effect is very much lower, as noted in connection with the experiment first described. Such plants may be found, however, by growing large enough progenies of seedlings, and we have so far identified about fifty of them. Among these, four individuals showed loss of the A effect but fully normal pollen. All of the others had aborted pollen, and in all cases this was empty or nearly empty. Three of the four mutants showed the ph71enotype of a B PI. They are designated a^3 ap!5 an^T > aUJ-°. The fourth mutant, though green as a seedling, showed faint anthocyanin coloration in later growth and deepened to a light purple at maturity. It is designated A^. The chief characteristics of these induced mutants, with reference to the criteria which have been mentioned, are as follows: (1) Phenotype. Except in the case of A-^ no consistent difference has been found in the phenotype of the mutants and that of ai In all six the aleurone is wholly colorless with C Ft A2, and the plant is typically brown with B PI. The pericarp is red with A P but has not yet been seen with a P. With au3 B PI a considerable amount of purple pigmenta- tion was observed, chiefly in the upper half of the lower leaf sheaths, but similar coloration has been found in a B £1 plants extracted from the same culture. In segregating progenies from amutant/a.. x a 3 PI and amutant/a x aP B £1 , it was not found possible to distinguish the mutant a from the standard a in any of these six cases. The phenotype of A ^ is clearly distinguishable from A, a, and aP in plant color, but it is not always distinguish- able from aP in aleurone color. The plant color at maturity (with B Pi) is more similar to A than to aP, and the plant does not appear brown at any stage. The- cob is reddish purple. The extracted pigment includes a considerable quantity of anthoxanthin as well as anthocyanin. The purified anthocyanin is distinct from both chysanthemin (A) and the anthocyanin of aP. (2) Gametophytc viability. aAi is transmitted through female germ cells but in reduced proportion, seldom in more than 30 per cent of the expected number. Seeds heterozygous for the variant are reduced in size. There is no trans- mission of the type through pollen of the heterozygous plant. •V j y / and aA show full viability in the female gametophyte, and the seeds are full size. Although the pollen in both these types is fully normal in appearance, transmission of 379 the mutant is reduced in pollinations from heterozygous plants, ordinarily to 25 to 40 per cent of the expected numbers. Self-fertilization of A/a^ plants yields no colorless seeds, even though the same pollen used on a C R testers both before and after selfing shows transmission of the mutant a^. This type therefore appears to be zygotically lethal when homozygous. The same result is obtained with ax ,̂ though the trials in this case are less extensive. f and show full male and female viability and transmission. is also fully viable in male and female gametophytes and regular in transmission. (3) Relation to Dt. The reaction to Dt is determined chiefly by examination of the aleurone of seeds produced by the cross ci^utant/^p ^ Dt x artless jyt j)t in comparison with sister ears of a aP Dt Dt similarly pollinated. Supplemen- tary determinations have been made in other ways. None of the mutants show regular dotting comparable to that of a. Occasional seeds may show a single dot, but this may be ascribed to the tester as well as to the ^mutant# Evidence on dotting in the1 homozygous amutant Dt combination is still scanty and has shown no dots so far. L. J. Stadler, J. IV. Cameron, K. 0. DeBoer, Herschel Roman University of Puerto Rico, Rio Piedras, Puerto Rico Although I am concerned primarily with corn breeding, I have started genetical studies of corn grown in Puerto Rico. There are many mutants found in local corn, such as white and yellow seedlings, various other chlorophyl deficiencies, male and female sterility, narrow leaf, tassel seeds, vivipary, brown midrib, red pericarp, variegated pericarp, and others. Whether these mutants have been introduced from the North, and subsequently incorporated into local corn, or are local in origin it is difficult to tell with certainity. However, it is well known that corn from the mainland is not adaptable to local conditions, and the few attempts to 380 introduce it to Puerto Rico have failed. The corn imported from other regions, such as Santo Domingo, Cuba ana Argentine is used exclusively for feed. Many crosses were made between some of these mutants and unrelated stocks, and F2's and backcrosses are expected to be raised this spring. *For the present I want to mention two interesting cases: brown midrib and tassels, and forked or split stem. Brown midrib and tassels. The Fn data suggest that we have a new dominant mutant, tentatively designated Bm-b, for the development of brown pigment in midrib and tassels. The color appears rather late, before tasseiing, and varies in intensity especially in tassels, sometimes approaching color of tassels of a B PI plants. This mutant was founa in one of the inbrea lines. Bm-b plants were selfed and crossed to three unrelated stocxs. The selfed plants had also red pericarp and cob. The five crosses segregated in the following ratio: Bm-b Pvv bm-b 2 bm-b Pvv bm-b p. 193 2 ’ 0 " ’ 183 The result suggests that Bm-b is closely linked with P. The presence of the red pericarp in 3m-b plants, as well as the development of anthocyanin in seedlings of all Fj_ plants indicate that the development of brown color in tassels and midrib is not due to a. also there is evidence that we are dealing with red and not cherry pericarp, as there is no PI involved in these crosses. Forked or split stem. A number of plants were observed in several cultures in which the stem is split or forked. The forking may occur in any node. If forking takes place at the node below the ear, then two ears and tassels arc formed. From t\ o selfed forked ears UU plants were raised, all of which were normal, non forked. The F^ between forked and normal plants yielded: normal Forked 153 2 2 26 0 JL1 1 Total 216 5 G. a . Lebedeff 381 IV. Miscellaneous Co-op Items 1. Co-op stocks. An effort is being made to grow each stock in our collection at least once every three years. To maintain vigor, especially in the naturally weaker stocks, we shall follow a practice started a few years ago. The co-op stocks are crossed with standard inbreds I (U.S. ho. 204) and II (West Branch). The desired characters are then recovered from each of these hybrids, and crosses are then made between these desired sorts from the two sources. 2. Assignments of chromosomes for mapping. In News Letter 12, April 15, 1939, page 39, there is given a list of persons who are mainly responsible for linkage studies on the different chromosomes, and for the building up of linkage stocks. At the Christmas meetings in 1940, this list was examined by the co-operators present, and a few changes were made. The revised assignments follow: Chromosome 1 Emerson Chromosome 2 Rhoades and Clokty Chromosome 3 Brink and Woodworth Chromosome 4 Singleton and Brunson Chromosome $ Burnham and Car Hedge Chromosome 6 Burnham, Lebedeff and Stadkr Chromosome 7 Jenkins and Fraser Chromosome 3 Sprague and Perry Chromosome 9 Shafer and Eyster Chromosome 10 Lindstrom 3. Personals. (a) Carlos A Krug of Sao Paulo, Brasil, is spending a year in this country, with the special purpose of studying the genetics and cytology of citrus, at Riverside, California. Krug brought to thu U.S.A., 60 types of maize collected by his assistant in Bolivia, Peru, Ecuador, and Columbia. These have been added to the Co-op stocks. Small amounts of seed can be spared to cooperators who are especially interested. (b) D. G. Langham of Venezuela is in this country for a few months, for the purpose of collecting corn and of working on a special problem in con- nection with his research. (c) Two of our number, M. M. Rhoades and B. McClintock will be at Cold Spring Harbor this summer, along with Muller, Wright, Nebel and other geneticists (d) R. A. Emerson left Ithaca early in February for a six-weeks vacation in Florida. 382 V. Maize Publications Since the preparation of the list of publications in News Letter 14, March 5, 1940, the following articles have appeared, in print Anderson, E. G. and Brink, R. A. - Translocations in maize involving chromosome 3. Genetics 2j5: 299- 309, 1940. Andres, J. M. - Analisis genetico del color de endosperma en algunos maices comerciales Argentinos. Inst. Genet, Univ. Buenos Aires vol. 1: 25 p., 1939. Avery, G. S., Jr,, Creighton, H. B. and Shalucha, B. - Extraction methods in relation to hormone content of maize endosperms. Amer. Journ. Bot. 27: 289- 300. 1940. Beard, D. F. - Relative values of unrelated single crosses and an open-pollinated variety as testers of inbred lines of corn. Abstr. Ph.D. thesis, Ohio State Univ. 9-18, 1940. (Includes discussion of susceptibility to Diplodia Zeae). Bercaw, L. 0., Hannay, A, M. and Larson, N. G. - Corn in the development of the civilization of the Americas. A selected and annotated bibliography. U.S.D.A. Agr. Econ. Bibl. JF7: 195 p., 1940. Bonnett, 0. T. - Development of the staminate and pistillate inflorescences of sweet corn. Journ. Agr. Res. 6£: 25-37, 1940. Borgeson, C. and Hayes, H. K. - The Minnesota method of seed increase and seed registration for hybrid corn. Journ. Amer. Soc. Agron. 22: 70-74, 1941. Buss, H. - Die Problemstellung in aer deutschen Maiszuchtung. Deut. Land. Presse. 67: 87, 1940. Capinpin, J. M. and Rollan, A. 0. - Hybrid vigor in the first generation crosses between strains of Cebu corn. Philipp. Agr. 28: 491-503, 1939. Carnegie Institute Washington - Maize cultivation in northwestern Guatemala. (Compiled from data collected in the field by Raymond Stadelman). Carnegie Inst. Wash. Pub. 212 : 83-263. 8 pi. map, 1940. Processed. 383 Clark, F. J., and Copeland, F. C. - Chromosome aberrations in the endosperm of maize. Amer. Journ. Bot. 27: 247-251, 1940. Clark, F. J. - Cytogenetic studies of divergent rneiotic spindle formation in Zca mays. Amer. Journ. Bot. 27: 547-559, 1940. Dungan, G. H. - Influence of age on the value of seed corn. Trans. Illinois Acad. Sci. 21: 28-29, 1940* Eckhardt, R. C., and Bryan, A. A. - Effect of the method of combining the four inbred lines of a double cross of maize upon the yield and variability of the resulting hybrid. Journ. Amer. Soc. Agron. 32: 347-353, 1940. Eckhardt, R. C. and Bryan, A. A. - Effect of the method of combining two early and two late inbred lines of corn upon the yield and variability of the resulting double crosses. Journ. Amer. Soc. Agron. 32: 645-656, 1940. Edwards, E. T. - Thu American hybrid maize programme. Journ. Austral. Inst. Agr. Sci. 6: 146-153, 1940* ti Fujita, T. - Uber die Organstellungen bei Maiskolben, Japan. Journ. Bot. 10: 113-140, 1940. Gaossler, VT. G., Hixon, R. Li. and Haber, E. S. - The quantity of pericarp in several hybrids and inbred strains of sweet corn. Iowa State Coll. Journ. Sci. 1 4 : 379-383, 1940. Gini, E, - Estudios sobre osterilidad en maicuS regionales de la Argentina. Anales Inst. Fitotecn. Santa Catalina (La Plata, Arg.). 1: 135-158, 1940. (Eng. Sum.) Granor, E. do A. - Variacoes do valor de "linkage". Revista Agr. (Piracicaba) lj$_: 168-175, 1940. (Eng. Sum.) Haber, E. S. - Sweet corn hybrids. Iowa Agr. Exp. Stat. Bull. N.S. P15: 437-468, 1940. Heyne, E. G. and Brunson, A. M. - Genetic studies of heat and drought tolerance in maize. Journ. Amer. Soc. Agron. 803-814, 1940. Hirschhorn, E. and Hirschhorn, J. - Accion del pH sobre los caracteres culturales del carbon del maiz. Ustilago Zeae (Beck) Ung. Physis (Buenos Aires) 18: 223-251, 1939. 384 Hoerner, I. R., and Snelling, R. 0. - Effect of polli- nation upon chemical composition of silks of certain inbred lines of maize. Journ. Amer. Soc. Agron. 22: 213-215, 1940. Hudson, W. A. - Sweet-corn hybrids for canning and market. Illinois A.E.S. Circ. 504. 20 p. 1940. Hudson, W. A. - Sweet-corn inbreds and crosses. Illinois Agr. Exp. Stat. Bull. 4,66: 279-355, 1940. Janetzki, C. - Probleme der Maiszuchtung. Mitt. Landw. 21: 763-770, 1940. Jenkins, M. I., and others - Report of the third Corn Improvement Conference held at the University of Missouri Columbia, Missouri, November 27 and 23, 1939. 21 p. Washington, D. C. 1940. Mimeographed. Johnson, I. J., and Hayes, H. K. - The value of hybrid combinations of inbred lines of corn selected from single crosses by the pedigree method of breeding. Journ. Amer. Soc. Agron. 2k: 479-485, 1940. Jones, D. F. - Nuclear control of cell activity. Science 38: 400-401, 1938. Kumazawa, M. - On the vascular course in the male inflorescence of Zea Mays. Vascular anatomy in maize. I. Bot. 11ag. Tokyo 21- 495-505, 1939. (Eng. Sum.) Langham, D. G. - Hibridos de maiz. Revista Asoc. Argent. Criad. Cerd. 1£: 23, 25, 27-28, 1940. Langham, D. G. - Hibridos de maiz. Agricultor Venezolano 4: 10-15, 1940. Lebedeff, G. A. - Failure of cytokinesis during microsporogenesis in Zea Mays following heat treatment. Cytologia 10: 434-442, 1940. Lee, F. A., and Sayre, C. B. -- Maturity studies on new sweet corn hybrids. Proc. Amer. Soc. Hort. Sci. 37. (1939): 759-762, 1940. Lincoln, R. E. - Bacterial wilt resistance and genetic host-parasite interactions in maize. Journ. Agr. Res. 60: 217-239, 1940. McClintock, Barbara - The stability of broken ends of chromosomes in Zea mays. Genetics 26: 234-282. 1941. 385 Marino, A. E. - Una variacion tardia en maiz. Reprinted from Revista Argentina Agron. 6 : 237-240, 1939 as Publ. Techn. Inst. Exp. Invest, y Fomento Agr. Ganad. Wo. 15, 1939. Mario, A. E. - Heroneia del color de aleurona on el maiz "piamontes". Physis (Buenos Aires) 18: >47-67, 1939. Millang, A., and Sprague, G. F. - The use of punched card equipment in predicting the performance of corn double crosses. Journ, Amer. Soc. Agron. 32: 815-816, 1940. Miller, E. S., and Johnson, I. J. - Inheritance of chlorophyll in F^ crosses made reciprocally between selfed lines of corn. Proc. Soc. Exp. Biol, and Med. 4 4: 26-28, 1940. Murdoch, H. A. - Hybrid vigor in maize embryos. Journ. Hered. XL: 361-363, 1940. Randolph, L. F. and Hand, D. B. - Relation between carotenoid content and number of genes per cell in diploid and tetraploid corn. Journ. Agr. Res. 60: 51-64, 1940. Rattray, A. - Field selection of seed maize. Rhodesia Agr. Journ. XL'- 259-263, 1940. Reeves, R. G., and Stansel, R. H. - Uncontrolled vegetative development in maize and teosinte. Amer. Journ. Bot. 27: 27-30, 1940. Rhoades, M. M. - Studies of a telocentric chromosome in maize with reference to the stability of its centromere. Genetics 2j>: 483-520, 1940. Robbins, \L J. - Growth substances in a hybrid corn and its parents. Bull. Torrey Club 67: 565-574, 1940. Sanguineti, M. E. - Estudio del caracter "siamensis" en maiz (Zea mays L.) Anales Fitotecn. (Argentina) 1: 17-134, 1940. (Eng. Sum.) Sansome, T. K. - Breeding diploidia resistant varieties of maize. Rhodesia Agr. Journ. XL' 442-444, 1940. Saunders, A. R. - Hybrid maize. Farming So. Africa. 15.: 310-312, 1940. Schmidtt, C. G. - Cultural and genetic studies on Ustilago zeae, Phytopath. 30.: 381-390, 1940. 386 Schultz, J., Caspersson, T. and Aquilonius, L. - The genetic control of nucleolar composition. Proc. hat. Acad. Sci. 26: 515-523, 1940. (Zea mays and solanum) Sharman, B. C. - Stamen lodicules in maize. Nature 144: 1093. 1939. Singleton, h . R. - Influence of female stock on the functioning of small pollen male gametes. Proc. hat. Acad. Sci. 26: 102-104, 1940. Singleton, h. R., & Mangelsdorf, P. C. - Gametic lethals on the fourth chromosome of maize. Genetics 25: 366-390, 1940. Sneiling, R. 0., Blanchard, R. A., and Bigger, J. H. - Resistance of corn strains to the leaf aphid. Aphis maidis Fitch. Journ. Amer. Soc. agron. 32: 371-381, 1940. Stringfield, G. H. - Evaluating new corn hybrids. Grain and Feed Journ, 8£: 347, 1940. Southern Corn Improvement Conference - Report of the first (organization) meeting - November 24, 1939. 37 p. 1940. Anon. - Corn comes of age. (A readable story about hybrid corn - its past, its present and a look into its future). Fert. Rev. 8-9, 11, 1940. (Based on interview with Jenkins). 387 Papers in Press Longley, A. E. - Knob positions on teosinte chromosomes Journ. Agr. Res. Chromosome morphology in maize and its relatives. (a review). Submitted to Botanical Review, but not yet accepted. Saboe, L. C. and Hayes, H. K. - Genetic studies of smut reactions in maize by means of chromosomal trans- locations - Submitted to Journ. Amer. Hoc. Agron. 388 VI. New Genes 1. Five alleles of a for aleurone color. Mo symbols given as yet. See contribution by H. M. Rhoades, Columbia University, item 2.. 2. A new member of the r series for aleurone color. See report by M. M. Rhoades, item 5. 3. Mew gene for pollen abortion pa contribution of C. R. Burnham, item 1. U• An Rch allele of R contribution of E, G, Anderson, item 1. 5. Mutations produced by irradiation. See contribution by L. J. Stabler and co-workers. 6. Bm- b- brown midrib and tassel. Contribution of Lebedeff from Univ. of Puerto Rico. 389 MAIZE GENETICS COOPERATION NEWS LETTER 16 1942 The data presented here are not to be used in publications without the consent of the authors. Department of Plant Breeding Cornell University Ithaca, N. Y. 390 MAIZE G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I T H A C A , N E W Y O R K December 10, 1941 To Maize Geneticists: Circumstances beyond the control of mortal man have again laid Maize Genetic Cooperation on my doorstep* It is, of course, too early to know what can be done next summer by any of us. But I feel that such fundamental and long-time undertakings as ours should not be lightly abandoned. I plan, therefore, to assemble material for a Maize Genetics News Letter to be mailed on or about the first of February next. Since I shall be away from my office during much of February and March, I must have your reports by January 15* Even if you cannot make a complete report by that time, please send me whatever you can get ready. Sincerely, C/C , £ > -> 1 -a RAE:P R. A. Emerson 391 Vp /. / ̂ CONTENTS Page I. Professor Fraser....................... * ............ 1 II. Reports from cooperators............................. 2 Columbia University............................. 2 Connecticut Agricultural Experiment Station. . . 6 Cornell University . . . . . ................... 8 Harvard University ............................. 19 Illinois University................................ 21 Minnesota University . . ..........................21 Missouri Botanical Garden..........................22 Missouri University................................ 24 U. S. Department of Agriculture and Iowa State College..........................33 Wisconsin University . . . ..................... 34 III. Maize publications............................... 35 IV. Inventory of seed stocks propagated in 1940 and 1941 38 V. Index of seed stocks propagatedi n 1940 and 1941. . . 50 392 I. PROFESSOR A. C. FRASER Somewhat more than a year ago, when I expected to retire at the end of June, I persuaded Professor Fraser to take charge of Maize Genetics Cooperation. I did not retire, and now Pro- fessor Fraser has gone. He assembled the material for the 15th News Letter. It was done in his characteristically careful way. It has pleased me a lot to hear more than one of you say that last year's News Letter was the best one so far put out. Without the knowledge of any of us, Professor Fraser had been treated by a specialist for over a year. He did not meet his class in advanced genetics after the spring vacation, but he did prepare seed for planting and staked glossy seedlings in the field. Dr. Murray and I made pollinations for him in the summer and Dr. Murray made the final records from his cultures. Some of these are reported in this News Letter. Professor Fraser was primarily a teacher. He was unusual- ly successful with both undergraduate and graduate students. Many of you, who had courses with him, have told me this and more. You who were thus associated with him for a few years will feel this loss. To those of us who had been his colleagues for many years, his death came as a profound shock. Our memory of many things about him is small consolation. His ability, his determination, his untiring energy and resourcefulness, his never failing cheerfulness - he "kept his chin up" to the end - his willing helpfulness, and withal his unassuming manner, all these memories of him force upon all of us an ever growing sense of our loss. R. A. Emerson 393 II. REPORTS PROM COflPERATORS The presentation of data in these News Letters is not regarded as constituting publication. These data should not, therefore, be used in published papers without the consent of the authors. R. A. Emerson Columbia University, New York City 1. Location of Dt in the short arm of chromosome 9. - Fg data presented in the 1941 News Letter indicate that Dt is situated close to the yg2 locus at the end of the short arm of chromosome 9. These data also suggested that Dt was about ten units beyond yg2. However, Creighton found only one percent recombination between yg2 and the terminal knob. Backcross tests recently completed prove that Dt does lie approximately seven units beyond yg2. The low recombination value of one percent for the y#2-knob region may be ascribed to the disturb- ing effect on crossing over of the large heterozygous knob present in Creighton's set-up. The backcross data are as follows: Dt + + + + yg2 sh wx 0 1 2 1-2 2-3 i1l-9l Total 333 278 22 29 76 86 32 64 0 3 2 3 0 6ll 45 162 146 3 5 0 972 Dt-Y£2 5.2^ Y£-Sh y i M Sh-Wx 15. Dt + + + yg2 sh 0 1 2 1-2 Total 306 228 18 33 S3 93 2 4 53^ 51 176 6 767 Dt-Yg2 7 M Yg2-Sh 23.7$ Dt+ ±± ±X&2 Total Dt f 283 24 25 293 625 yg2 Dt-Yg2 l . % 394 Dt + + + sh vx 0 1 2 1-2 Total ^45 330 115 n o 35 76 3 675 225 161 7 1068 Dt-Sh Sh-Wx 1 5 .7# Dt+ Dt sh ±± +sh Total Dt + 838 277 324 755 2204 + sh Dt Sh 27 . % 2. In a culture with A B PI and A b PI plants the Rp and rS^ alleles were segregating. A b PI R^? plants had green anthers with colored glumes. There was no color at the base of the culm but an occasional small blotch of color was found along the culm. Possibly a new R allele. 3. Jenkins gave the writer a selfed ear of inbred Hy that was segregating for what appeared to be a green seedling char- acter. This new recessive mutant is linked with either C or R. Inasmuch as A B pJL plants homozygous for this gene have a deep bronze color instead of the usual red, this gene has been ten- tatively designated "bronze,f (symbol bz). A b £l_ and A b PI plants homozygous for bjz are not green but have a bronze color at the base of the culm. Some strains of A b jcl and A b PI plants homozygous for bz have chocolate colored anthers while other strains have green anthers. Some interactions with the R alleles may be involved here. The effect of bz on the color of A B PI plants or on pericarp color has not yet been determined. The effect of bz on aleurone color Is also unknown since it arose in a line homozygous for recessive c. and r and its being linked to one of these factors makes the aleurone effect diffi- cult to determine. The bz gene has a rather remarkable pleio- tropic effect. In addition to affecting the anthocyanin system it also causes considerable pollen abortion. The sterility effect of bz is variable from season to season. At Arlington, Virginia in the summer of 1940 the amount of aborted pollen was so great that the anthers were shriveled and many failed to dehisce while In the summer of 1941 at Cold Spring Harbor little or no pollen abortion was evident. A. Location of dwarf-7. Singh reported that d7 belonged in the tenth linkage group approximately 27 units to the right of R. Singh's placement of d7 rested upon the linkage of d7 with aleurone color in P2 populations segregating for both C and R, and upon an Fg population of 109 individuals segregating for d7 and golden-1 where he found 35 percent recombination 395 1—1 CM between d7 and g. Singh’s placing of d7 in chromosome 10 rests entirely upon the loose and dubious linkage of d7 with g. The writer has been unable to find linkage of d7 with genes in chromosome 10. Fp data from cultures segregating for d7 and shrunken show 24 percent recombination. Apparently d7 belongs in chromosome 9 and since d3 shows 25 percent recombination with sh it is not unlikely that d7 and d3 are identical. At any rate it is clear that the d7 locus should be dropped from the map of the tenth linkage group. 5. Inasmuch as the writer was assigned chromosome 2 he has from time to time collected additional data on the location of certain genes placed in the map by two-point tests. The floury locus was placed between gk and tg by two-point data. This has been confirmed by three-point tests. Some of the data involving floury are presented below: lg El B FI v4 lg gl b V4 v4 Lg G1 b fl V4 B.C. for lg gl B Fl for ^4 Lg-Gl 16%; Gd-B 16%; B-Fl 16%; F1-V4 14#; B-V4 2J% The order i3 lg gl B Fl V4 B Fl ts v4 b Ts-v4 b fl Ts V4 ts-v4 B.C. for B Fl F2 for ts. and v4 B-FjL 19%; Fl-Ts 3$> B-Ts 21^; F1-V4 l3% ; B-V4 J>2fo The order is B Fl ts v4 Summary of unpublished linkage data for chromosome 2 XY Percent Genes Phase XY Xz xY 2LY Total r e c omb ina t i on B Fl CB 5^9 135 129 663 1476 IS B Ts RS 254 101 413 27 795 21 B V4 RS 430 204 716 76 1476 26 Fl Ts RS 576 243 768 7 1391* 3 Fl V4 RS 569 281 891 60 • 1801 18 Gs2 Fl RS 161 212 113 19 505 17 M. M. Rhoades 6. The following experiment was undertaken to determine if the pollen tubes obtain nutriment from the silks as they grow downward or whether food materials stored in the pollen grains are the chief source of energy. 396 Pollinations were made one day after cutting back the silks, so that brushes of silks approximately l|- inches long were available. Following pollination that portion of the silk (with the attached pollen grains) extending beyond the husks was cut off at intervals of y, J, 1, l i , 2, 2^, 3, and 6 hours after pollinating. Silks removed at different intervals of time were fixed in alcohol and later stained with carmine- chloral hydrate. It was found that germination occurred within the first half-hour. Germinated grains on silk3 removed at the different time intervals were examined cytologically to determine whether or not the two sperm cells and the tube nucleus had passed into the silk. The data are given as follows: Table 1. Percent of germinated grains with no (0), one (l), and two (2) sperm nuclei, and having (l) or lacking (0) a tube nucleus on silks removed at different time intervals after pollination. Hours 2 3perm Ho. of after cells grains pollin- 1 tube 2 sperm 1 sperm 1 sperm 0 sperm 0 sperm examin- ation nucleus 0 tube 1 tube 0 tube 1 tube 0 tube ed 12 92 0 0 0 6 2 50 1 L* 80 4 4 0 12 0 25 1 32 0 0 2 7 9 52 li 59 1 1 0 20 13 61 2 17 2 2 1 9 69 120 H 0 0 0 0 5 95 20 The average number of grains on each examined silk was approximately twenty but considerable variation was found. Every silk examined, however, had a number of established grains. Most of the sperm and tube nuclei pass out of the pollen grains between one and two hours after pollination. The sperm cells usually precede the tube nucleus in passing into the pollen tube. Four hours after pollination the pollen grains are nearly empty. The pollen grains retained a considerable portion of their contents two hours after pollination, even though the sperm nuclei and the tube nucleus had entered the silk. Pollen grains cut off before all of the food reserves had passed into the pollen tubes might not achieve fertiliza- tion for lack of sufficient nutriment if the growing tubes obtain little or no nourishment from the stylar tissue. The pollen tubes would contain the sperm and tube nuclei, but only part of the total food material stored in the pollen. If the pollen tubes obtained nutriment from the silk, they would con- tinue to grow and all the ovaries would be fertilized. If, however, the pollen tube could not obtain sufficient 397 nutriment from the silk, it would grow only until the available food material in the pollen tube was exhausted. Many of the ovaries at the bottom of the ear would not be fertilized, be- cause the pollen tubes lacked the energy to grow a longer dis- tance. Seed set was determined at maturity. Table 2. Number of ear3, total number of seeds, and the per- cent of seeds found in the upper half of all the ears of corn for each time interval. Series A ______ Hours after pollination 1 2 2^ 3 3? 4 6 Number of ears 3 6 5 6 9 10 4 Total no. of seeds 1 193 862 337 1233 2607 1380 Percent seeds in 64 71 75 72 53 52 upper half Series B Hours after pollination : 1 2 3 : 4 00 Number of ears : 3 3 8 : 7 11 Total no. of seeds : 5 26 81 : 408 3132 Percent seeds in : 73 69 : 68 52 upper half (Note: oo= silks were not removed] The number of seeds in the upper half of the ear was con- sistently greater than in the lower half at the time intervals when food material still remained in the pollen grain at the time of removal. Inasmuch as nearly all of the contents of the pollen grain had been discharged into the pollen tube by four hours after pollination but there were an appreciable number of unfertilized ovules at the base of the ear it seems that prac- tically all of the stored reserves are needed for the long journey to the basal ovules. It is doubtful if the stylar tissue offers any nourishment to the growing pollen tube. Sidney Wiesner Connecticut Agricultural Experiment Station New Haven, Connecticut 1. Paired red and dark purple mosaic areas in light purple seeds, heterozygous for Pr pr pr, rarely show growth changes. In some of these cases the red area grows out beyond the normal cells, sometimes the dark area. In the few cases that have been examined so far no growth changes accompany the exchange of both Pr and Bt. Since Bt_ is close to the centromere, pre- sumably, paired changes that include Pr and Bt_ involve an exchange of almost the entire right arm of chromosome 5. If the alteration in growth were due to a loss or accumulation of specific growth regulating genes or to a general chromosome 398 unbalance it would be expected that all of the paired changes involving both Bt and Pr would be altered. Since they are not, this is a strong indication that growth changes result from breaks and reattachments at critical places in the chromosomes. 2. Paired pericarp mosaics, especially those that may oc- cur in plants heterozygous for and P^, would make possible a distinction between reciprocal translocation and somatic crossing over. In plants of this composition red-seeded, red- cobbed ears would show colorless seeds underlaid with red cob adjacent to colored seeds over white cob. Any mosaics of this type should be examined cytologically and put on record. The writer would appreciate having any of these mosaics, especially where the areas involved cover several seeds. D. F. Jones 3. Effect of environment on aleurone color - Marcross sweet corn with the aleurone constitution A C r Pr was changed to a purple aleurone (phenotype A C R Pr) by growing in the greenhouse in the winter time with no additional light. The corn was planted on January 21, 1941 in soil fertility plots where different types of phosphorous fertilizers were being tested. The fertility in all plots was sufficient to produce a normal crop of corn. In some cases ears were produced in the tassels as Is characteristic of corn grown in this latitude with no extra light. Many fully purple kernels were found on the main ears as well as those produced in the tassel. One tassel ear had all the kernels fully colored similar to any A C R Pr stock. Examination showed this color to be in the aleurone layer. Seeds from the fully colored tassel-ear were planted In the field in the summer of 1941. Three selfed ears showed no aleurone color. The kernels were all Y su. Ears crossed by A C. R Pr were entirely purple, also those crossed by a C R pr and A c _ R. Ears crossed by ACr were colorless showing the aleurone constitution to be A C r Pr. No explanation is readily available for the apparent changing of r or R when grown in the greenhouse. The experiment is being repeated in the greenhouse In 1942. W. R. Singleton 4. In a field corn test in 1938, 311 different hybrids and inbreds were grown. A total of 14,916 ears were picked and of this number 26 (from 22 different lines) were classified as semi-sterile. This is not a good determination of the fre- quency of changes giving semi-sterility, but is an indication of the types of changes that occur. Progeny of 24 of the 26 ears have been grown for one to three generations to test the transmissibility of these sterilities. Twelve were definitely transmitted, three had questionable transmission and nine were not transmitted and were probably due to environmental or physiological causes. Nine of the twelve have been examined cytologically, and in these the following changes were found: 399 asynapsis, a 1-6 translocation, a 6-8 translocation, a pollen lethal character with no apparent chromosomal change or defi- ciency, and a long inversion in chromosome 1 including the centromere. It is of particular interest that the inversion in chromosome 1 was found in three different hybrids having as one parent, the inbred U.S. 4-3. It would be desirable to know if 4-3 has been found to have this inversion in the heterozygous condition and whether any unusual number of semi-sterile ears have been found in hybrids with 4-3. The 4-8 inbred used in the hybrids grown in Connecticut was not homozygous for the inversion 3ince all the ears were not semi-sterile. It could have been obtained by contamination, but it seems unlikely that three hybrids with one parent in common would have been so af- fected. The Inversions are apparently the same cytologically although crosses between them have not been made as yet to detect any differences. Twelve semi-sterile ears, obtained from other field corn tests and sweet corn trials, have been tested for transmissi- bility. Five were not transmitted, one possibly is transmitted and six were transmitted. From the last six a lethal ovule character was found, a 2-5 translocation and a 6-9 transloca- tion. Three have not been examined cytologically. 5. An unusual example of a somatic change was found in a plant heterozygous for the translocation T5~9a. The ear on this plant had approximately half the s-ilks green and half red. Other plants from the same cross had green silks, with the ex- ception of two plants having a few red silks and all others green. Although the ear which was about half red and half green wa3 open pollinated, tests are being made to determine if the change was only in maternal tissue. F. J. Clark Cornell University, Ithaca, N. Y. 1. White-capped red pericarp - E. G. Anderson reported (Genetics 9:442-453. 1924) an allelic series of maize pericarp and cob colors with their genes at the locus of P. These in- cluded self red pericarp with red cob R-R (Anderson's symbols are used here, the first letter representing pericarp and the second cob color), colorless pericarp with red cob W-R., color- less pericarp with white cob W-W, variegated pericarp and cob V-V, mosaic pericarp and cob M-M, white-capped red pericarp with red cob C-R, and white-capped red pericarp with white cob C-W. That these combinations of pericarp and cob colors con- stitute an allelic series has not been questioned heretofore, so far as I am aware, and is not now questioned except for C-R and C-W. In fact, all the data with which I am familiar tend to substantiate Anderson's conclusions except for white-capped red pericarp. Heretofore I have regarded C-R and C-W as be- longing to the P series of alleles and long ago (Nebr. Agr. Exp. Sta. Rpt. 24: 57"90. 1911) published records for C-W - 400 involving exceedingly few individuals - in support of this idea. Anderson's records involved adequate numbers. For the backcross (C-W x W-R) x W-W, the two parental types only were obtained, 1634 C-W and 1751 W-R. But he reported that: "This cross is not wholly satisfactory, since heterozygous C-W is light colored, making immature ears difficult to separate from white." Pie found no red-cobbed ears with white-capped red pericarp, while the white-cobbed ones all exhibited this peri- carp color. But, in his description of W-R, he said: "Pericarp white (colorless) in some varieties, pale orange in others." If these statements seem to imply that both Anderson and I were wrong in our early Interpretations respecting C-W, I must admit that I have no evidence to support such an implication. But for C-R I shall here present evidence which indicates that the white-capped red pericarp of Bloody Butcher is conditioned by multiple genes. The C-W combination studied earlier by Anderson and by me is that seen in Northwestern Dent. The color patterns of the pericarp'of these two varieties are iden- tical in appearance and the intensity of pigment of both is reduced noticeably when made heterozygous by crossing with colorless pericarp types. In this respect both differ from self-red, variegated red, and mosaic red. It seems strange, therefore, that white-capped red of Northwestern Dent, C-W, should differ in inheritance from the apparently identical pericarp color of Bloody Butcher, C-R. Both Anderson (1924) and I (1911) reported crosses of C-W x W-R and of most of the other po33ible combinations of pericarp and cob color patterns, but neither one of us reported results of C-R x W-W. All the crosses to be reported here involve a single one of Dr. Wiggans’ Inbred strains of Bloody Butcher (C-R), his inbred #4. This was crossed with three others of his inbreds; namely, Cornell 11 inbred #3 (W-R), Luce’s Favorite inbred #1 (W-W) and Onondaga White Inbred #2 (W-W). Generations F2 and F^ and repeated backcrosses to W~W have been studied. Since in one of the crosses, C-R x W-R, white cob color is not involved, both parents having red cobs, I shall present first the evidence involving pericarp color alone from all the crosses. In the presentation to follow the intensity of pericarp color is indi- cated in six grades. Grade 0 indicates pericarp in which no tinge of color can be seen, grade 6 the color Intensity of the Bloody Butcher parent, grade 5 that of most Fp ears, grade 1 a barely discernible tinge of color and 2, 3 , 4 intermediate grades, in ascending order of color intensity. The mean grade of color intensity Is presented both for all ears and for ears with some color in the pericarp. In table 1 are given the records of nine different F2 cultures of the three crosses and of nine backcrosses of Fp to colorless pericarp. 401 Table 1 Gen-: Mean grade era-:Parent Progeny grades Total All : Colored tion jgrades 0 1 2 - 5 4 3 6 ears:__. f2 ; 5 103 9 76 114 117 159 18 596 3 . 1 ; 3.3 be -5 x 0 273 13 74 113 114 54 0 643 1.9 ; 3.3 The ratio of plants with colored to those with colorless pericarp is 4.8 : 1 for F2 and 1.4 : 1 for backcrosses instead of 3 : 1 and 1 : 1, respectively. The frequency distributions of individuals of grades 1 to 6 are those typical of multiple- gene inheritance. The mode and the mean grade are somewhat lower in the backcross than in F2 , just as F-̂ is of lower grade than the colored parent. Progenies of selfed F2 and of selfed backcross plants with diverse grades of pericarp color are recorded in table 2. Table 2 Number of Paren Pt rogeny grades :Mean grades Total : All Colored cultures grade 0 1 2 3 4 5 6 : ears ears 4 0 104 - - - - _ - 104 : 0 2 0? 35 12 - - - - - 47 : 0.3 1.0 14 1 171 227 38 - - - - 446 : 0.7 1.1 5 2 29 58 43 20 8 4 - 162 : 1.5 1.9 7 3 46 28 46 65 33 9 - 232 : 2.2 2.7 3 4 19 8 10 17 23 16 - 98 ; 2 .3 3.4 3 5 - 1 2 9 26 48 23 109 :4.7 4.7 2 6 - - 1 1 9 35 32 78 :5.2 5.2 Individuals of various pericarp-color grades of the first backcross generation were backcrossed a second or third time. The progenies of these backcrosses are reported in table 3. Table 3 Number Mean grades of Parent Progeny grades Total All :Colored cultures grades 0 1 2 3 4 5 6 ears: ears 5 0 x 0 206 — — 206 : 0 1 0?x 0 74 4 - - - - - 78 :0.05 1.0 4 1 x 0 65 63 - - - - - 128 •0.5 1.0 4 2 x 0 59 20 64 9 - - - 152 •1.2 1.9 1 3 x 0 35 - 13 13 - - - 61 •1.1 2.3 6 4 x 0 4o 34 35 42 19 2 1 179 *1.3 2.4 1 5 x 0 38 - - 5 40 7 - 90 ;2.3 4.0 Tables 2 and 3 not only exhibit frequency distributions characteristic of multiple-gene inheritance, but also demon- 402 strate that selection is effective in isolating diverse types, as in most instances of quantitative inheritance. In many of the crosses reported above, cob color, as well as pericarp color, was involved. In table 4 the data for P2 and the first backcross generations are presented for red-cob and white-cob ears separately. Table 4 Gen- Progenies Mean grades era- Parent Cob Grades Total All Colored tion grades color 0 1 2 3 4 5 6 ears ears (R 32 45 45 53 72 113 17 341 3.6 4.0 p2 (w 49 4 24 25 13 3 - 118 1.6 2.8 be 5 x 0 (R 48 6 38 41 40 37 2 212 2.7 3.4 (W 119 2 7 41 23 5 - 202 1.4 3.3 The segregation of cob colors was sharp without apprecia- ble intergrades between red and white. The ratios of red-cob to white-cob ears, 341 : llB and 212 : 202 in the P2 and back- cross generations, respectively, are approximately the 3 : 1 and 1 : 1 ratios expected where a single gene pair is concerned The mean grades for pericarp color were somewhat higher in the red-cob than in the white-cob lots. This is the more pro- nounced when mean grade is calculated from all ears, because a higher percentage of the white-cob ears have colorless pericarp than is true of red-cob ears. Prom the cross C-R x W-W, there have been obtained the four combinations; namely, C-R, W-R, C-V, W-W, expected on the basis of independent inheritance of pericarp and cob colors. The numerical relations, however, do not fit those of independ- ent inheritance - 9"3"3“1 and l-l-l-l - as indicated in table 5. Table 5 C-R W-R c - w W-W Total Observed 309 32 69 49 459 Calculated 258 86 86 29 459 Observed 164 48 83 119 414 Calculated 103.5 103.5 103.5 103.5 414 If we were dealing with dihybrid inheritance, these data would indicate linkage of pericarp and cob colors with 26% or 31$ of crossing over for F2 or backcross progenies, respective- ly. It is conceivable that there is one primary gene for white capped red pericarp which is modified in its expression by other genes. 403 Records of F-̂ , and of F2 after one or more backcrosses, are summarized in table 6. Table 6 Number Progeny Mean grades of Parent Cob Grades Total All Colored cultures grade color 0 1 2 3 4 5 6 ears ears (R 22 • • — 22 0 1 0 (W 14 - - - - - - 14 0 (R 27 94 35 _ - _ - 156 1.1 1.3 5 I (w 31 3 - - - - 34 0.1 1.0 2 2 (R 7 40 13 2 _ _ - 62 1 .2 1.3 (w 12 3 - - - - 15 0.2 1.0 (r 16 12 16 25 17 3 - 39 2.3 2.3 3 3 (w 7 2 4 4 4 - - 21 1.3 2.7 1 (R 3 10 7 11 1 - - 32 1.9 2 .1 3 (w 11 - - - - - 11 0 (R 16 12 7 17 44 24 _ 120 3.1 3.65 4 ( w 9 2 3 12 10 4 - 40 2.6 3.4 Individuals of various pericarp-color grades among back- cross and Fo progenies were backcrossed to W-W, with the results shown in table 7. Table 7 Number Progenies Mean grades of Parent TJoF TerIcarp grade Total All Colored cultures grades color 0 8 1 2 3 4 5 6 ears ears 2 0 x 0 79 79 0 (w 74 - - 74 0 1 0 (R 2 91 - - - - 93 1.0 1.0> X (w 30 30 0 (R 7 8 - - - -1 1 0 15 0.5 1.0X (w 17 8 - - - — — 25 0.3 1.0 1 -2 x 0 (R 8 7 7 1 - - 23 1.0 1.6 (w 20 — — — ““ — 20 0 6 4 x 0 (R 33 38 9 17 20 17 - 139 2.0 2.7 (w 39 8 19 13 11 15 105 1.9 3.1 ~ Tables 6 and 7 show at least that low grade pericarp color is closely linked with red cob color. That even this very low grade pericarp color cannot be allelic to cob color is shown by the occurrence of cultures in which the red-cob ears, as well as 404 the white-cob ones, exhibit no discernible trace of pericarp color. In addition to the cultures that segregated for cob color, there occurred, in F-, and backcross generations of the cross C-R x W-W, progenies^that bred true for red or for white cob color, as shown in table 8. Table 8 Number Progenies :Mean grades of Parent Cob Pericarp grade Total : All Colore cultures grades color 0 1 2 3 > 5_ 6 : ears ears 1 1 R 15 23 _ - - - 33 : 0.6 1.0 2 1 W 18 15 - - - - - 33 : 0.5 1.0 3 2 w 10 15 30 18 8 4 - 35 : 2.1 2.4 3 3 w 9 4 19 25 16 6 - 79 :2.7 3.0 1 5 R - 1 2 5 7 11 11 37 :4.3 4.3 1 5 W - - - 3 12 11 1 27 :4.4 4.4 2 6 ' R - - 1 1 9 35 32 78 :5.2 5.2 6 0 X 0 W 197 197 : 0 7 1 X 0 W 66 73 2 - - - - l4l :0.5 1.0 1 2 X 0 W 5 4 16 6 - - - 31 : 1.7 2.1 3 3 X 0 W 36 2 27 23 17 1 - l6l :1.3 2.8 3 4 X 0 w 24 12 15 28 7 - - 86 :1.S 2.5 It will be noted from table 8 that six cultures produced nothing but W-W ears like one parent of the original cross; that three cultures produced only C-R ears like the other par- ent but with considerable variation in intensity of pericarp color; that one culture had only C-W ears like Northwestern Dent but with some variation in pericarp color intensity; that, while no true breeding W-R lots have been obtained, two cul- tures (table 7) contained only W-R and W-W ears, from which homozygous W-R stocks can presumably be obtained. From all this it seems obvious that white-capped red pericarp of Bloody Butcher is not a member of the _P allelic series but is conditioned by multiple genes one or more of which are linked with red cob and therefore with P. So far as the P allelic series is concerned, Bloody Butcher is apparently W-R to which has been added other genes for pericarp color not of that series. Since white-capped red pericarp of Northwestern Dent is identical with that of Bloody Butcher in appearance and in hay- ing its intensity reduced in the heterozygous condition, it will be interesting to discover whether Anderson and I were wrong in our earlier interpretation and, if then right, what relation exists between C-W of Northwestern Dent and the C-W that has come from the cross of C-R x W-W. The study is underway. R. A. Emerson 405 2. Linkage data involving an and Ts^ or Tsg - Striking differences between complementary crossover classes were report e -d by Emerson 1941 News Letter (p. 13-15). These records^ n mo at y have been wholly accurate for the following reason. of St oh me e Ts plants failed to develop ears since the tassels no wt e rer emoved at the time of emergence. Classification of a f nr om the tassel when combined with Ts is difficult. There s fi om ri el ,a r progenies were repeated this summer and the classifica- tion of an based on the ear. + Ts^/an + + Tsj ++ an Ts^ an + 1941, tassels removed 17^ 109 5 288 1940, tassels not removed 183 80 8 238 + Tsg/an + + Ts6 ++ an Tsg an + 1941, tassels removed 75 36 17 67 1940, tassels not removed 213 159 50 151 The results of both plantings are essentially alike. may conclude that the unequal nature of the complementary cr ov oe sr s -classes is not primarily due to inaccuracies oi classifica tion but rather to some other cause. Using the totals of both seasons, the following ratios occur: Ts- cultures 370 Tsj : 715 + D/PE = .9 for 1:2 ratio 5^6 + : 539 an D/PE = .4 for 1:1 ratio Tsg cultures 355 Tsg : 413 + D/PE = 3.1 for 1:1 ratio 433 + : 235 an D/PE =3.3 for 2:1 ratio In the Ts- data, Ts7) is deficient while an is normal; whereas, in the Tsg data, Tsg is only slightly deficient ana an greatly so. If these effects are due to an interaction betwe a en n and either Ts-̂ or Tsg as Emerson 1941 News Letter (p. 15) suggests, the interaction is presumably different for the two tassel-seed genes. M. J. Murray 3. Chromosome 7 linkage data - Professor A. C, Fraser mad t eh e following field plantings last spring and marked the seed- 406 lings. I assume all responsibility for the records on the ma- ture plants and the following summary of the results (table l). Table 1 + + +/in v5 gl 0 1 2 1-2 Total 552 458 1 11 18 20 2 12 990 12 53 14 1054 Recombination percentages: in~y5 2.4, v5-gl 4.8 Ratios: 575 + : 48l in, 595+ : 46l v5, 585+ : 469 gl Percent non-germination of In seeds 20.6, of in seeds 23.4. Fraser in News Letter 1953 (p. 11) reported in-V5 = 4.5°/> VS-gl = 12.2$ where n = 1017 and in News Letter 195b (p. 14) ln-V5 « 6.$ V5“gi = 14$ where n = 10,565. The present records are obviously different from the previous ones in that crossing over In the V5-gl region is markedly reduced. While all the recessives were somewhat deficient, this in Itself probably does not account for the reduced crossing over. Fraser (News Letter 1940) Indicated that he was Investigating the reason for marked differences in the complementary crossover classes in the in-V5 region. A study of the lineage of all these cultures may perhaps clarify the present results. Table 2. + + +/y5 ra gl 0 1 2 1-2 Total 852 478 40 59 8 514 29 0 1510 79 522 29 1740 Recombination percentages: y5-ra 6.2, ra-gl 20.2 Ratios: 909+ ; 851 vp, 379+ : 861 ra, 1214+ : 526 gl Fraser (News Letter 1941 p. 19) reported crossover percent- ages as follows: v5~ra 7, ra-gl 6, gl-ij, l3. The present records agree for the first region but not for the second. However, the ratio of glossies to non-glossies is roughly 1:2. Table 5. + + +/ra gl ij. 0 1 2 1-2 Total 540 134 16 47 101 65 5 94 524 65 164 97 843 Recombination percentages: ra-gl 18.9, gl-i.i 50.8, Ratios: 460+ : 538 ra, 532+ : 266 gl, 455+ : 595 ij.. 407 The region ra-gl was also studied in another culture where 20 2 percent of crossing over was obtained. These two sets of data agree in fixing the length of this region at about lb-20 units. However, this is in contrast to the result of b units obtained by Fraser (News Letter 19^1)• Itie region gl-il is longer (30.8) than in the previously reported data 18 (Fraser News Letter p. 19) No final interpretation of these data will be attempted until I have had an opportunity to study the origin of all cul- tures. Even then, further work will probably be necessary. M. J. Murray 4. Trisomics - Seed weight. In order to get a relatively high frequency of trisomic plants the smaller seeds are often selected from a trisomic ear. A study was made to find how close a correlation exists between weight of seed and chromo some number and whether this correlation varies in different trisomic stocks. Random samples of from 50 to 150 seeds were taken from trisomic ears. In some cases, however, only relatively small numbers of seeds were available. Each seed was weighed to the nearest .01 gram and placed in its weight class. In most case t sh e weights when plotted against number formed a unimodal curve In some, however, bimodal curves resulted (see III x lg.̂ j. fhe seeds were germinated in trays and roots taken before trans- planting to the field. The results are expressed in table 1. 408 Table 1 % tri- Relative Weight Wo. of somics No. of length of of indi- in indi- extra Trisomic seed in % tri- vid- random vid- chromosome Stock mg. s omic s uals sample uals 85 II x L.F. Inbred 140-210 82 58 220-250 55 59 50 159 240-260 19 42 II x Inbred II 160-220 14 7 250-240 56 16 57 45 250-280 50 20 II x C. II Inbred 150-200 87 50 210-250 49 55 52 95 250-260 18 28 II x lg 150-180 80 5 190-200 61 18 59 52 210-240 17 29 79 III x L.F. Inbred 150-240 69 16 55 54 250-500 6 18 III x Inbred II 100-150 50 12 160-130 40 20 55 52 190-250 15 20 III x lg 2 140-160 100 51 170-180 50 16 45 91 190-240 5 44 78 V x Inbred II 120-160 65 52 52 89 170-250 52 57 60 VI x su2 140-200 77 50 210-220 12 42 50 105 250-260 10 51 60 VII x L.F. Inbred 70-110 75 11 45 22 120-150 18 11 VII x Inbred II 70-120 65 16 150-140 59 25 40 58 150-200 21 19 409 Table 1 continued % tri- Relative Weight No. of somics No. of length of of indi- in indi- extra Trisomic seed in % tri- vid- random vid- chromosome Stock mg. somics uals sample uals 60 VIII x L.F. Inbred 110-170 65 58 170-130 44 45 32 146 190-220 6 65 VIII x j 200-250 55 13 240-260 55 13 27 45 270-520 0 9 52 IX x v wx 120-160 46 13 170-180 71 24 22 113 190-220 5 76 ^5 X x L.F. Inbred 220-250 43 54 260-270 12 52 26 149 280-510 12 43 X x vlB 200-250 53 12 240-250 35 20 37 49 260-270 24 17 Table 2 Percent Relative 2n + 1 Percent length of plants 1,0 • microspores No. of extra Trisomic in pro- indi- with n + 1 indi- chromosome stock geny vlduals chromosomes viduals 85 II. X L.F • 50 139 50 212 79 III. X lg2 45 91 4l 167 45 X X L.F • 26 149 34 190 X X vl3 37 49 33 109 Relative Percent length of microsporocytes extra Trisomic with univalents No. of chromosome stock in Met. I individuals 35 II. X L.F. 30 247 79 III. X Ig2 - - 45 X X L.F. 49 372 X X vl8 37 300 410 5. Frequency of transmission of the extra c t hr ri os mo om se os m. e iD ni fferent trisomic stocks derived as c mh ar to em ro ns ao lm e 2 1p lants from tetraploids show decided diffe p re er nc ce en st ag ie n of trisomic plants in the progenies. Mark e en dc e ds i fh fa ev re - also been observed in univalent frequencie q su ,e n fc ry e of lagging in anaphase I and II and in othe m re i do es ti as i. l s A o fs tock in which 40$ of the progeny was tr fi os uo nm di c t oh a bd e one of the longer chromosomes in triplic o at th ee .r s At no -ck producing 24% trisomic progeny had one of the shorter chromosomes in triplicate. In order to test whether length of the extra c c ha rn o mb oe s oc mo er related with frequency of transmission, kno h wa nv e s tb oe ce kn s st ( udied. The data presented are incomplete but may be of some interest. As the table indicates, the frequency of trans t mh ie s se ix ot nr a o fc hromosome through the egg varies from 22% Di f tf oe r 5e 2n >t . stocks of the same trisome show considerable b vi al ri it ay - in frequency of 2n + 1 progeny. However, s tt hr eo rn eg ip so s ai tive correlation between length of the s eo xm te r aa n cd h rt oh me o frequency with which it is transmitted th e rg og u. g h S te hv e eral of the cases which are out of line may be due t t oh e small number of seeds available. Such explanations as abortion of ovules or diffe s re ee nd t iv ai la bility would not seem to account for the obse f re vr ee dn c de is f -in frequency of transmission since a clos p eo n cd oe rn rc ee s -is found between the percentage of proge 2 nn y+ l w ha in cd h t ih se percentage of microspores with the n+1 number l see table 2). Sporocyte studies, which have not yet been compl c ea tt ee d , a ig nr de ia ter frequency of univalents in the shorter c s hto rc ok ms o sow mi et h more lagging in Met. I. and the formation Ox a greater number of micronuclei. John Einset Harvard University, Cambridge, Massachusetts The readers of this News Letter may be interested in so o mf e my observations on maize in Mexico. I spent J tu hl ey ma on nd t hA su g ou fs t in that country, travelled approxi m mi al te es l yi n o ,f ji Of Ct een states and visited a number of the experiment stations. Maize is the universal crop in Mexico. It is s ea g role wv ne l f roto m altitudes of approximately 10,000 feet. i t ^Oe nv ee r sy ew eh se re, planted between peach and apple t p re er ea st e i nr e tg ei mo -ns; between bananas and pineapples in It t hei s trf or pe iq cu se .n tly encountered as an ornamental pl y aa nr td s i na n fd r op na tr ks. Volunteer maize plants appearing o ir n f ai e gl ad r dd ee nv oted to other crops are usually allowed to remain. 411 The average Mexican apparently has the same feeling toward the maize plant which the Southern negroe exhibits toward a water- melon vine. It distresses him to see it destroyed. The diversity of maize in Mexico is enormous. Near El Seco we saw many fields in which the plants were tasseling out at a height of about two feet. Near Monterey we saw fields irrigated with sewage water with stalks fifteen feet in height. We did not see the famous giant corn of the Jala Valley except in experimental plantings at the station near Leon. Much of the diversity, however, is environmental. In many respects Mexican maize is quite uniform. Practically all of the maize plants of the great central plateau of Mexico are highly pubescent and uniformly pigmented, either sun red or purple. Practically all of the maize in all parts of Mexico shows strong external indications of contamination with Tripsacum. It is a common opinion in Mexico that maize reverts easily to teosinte. A very intelligent Canadian manager of a large estate assured us that teosinte-like segregates appear in the maize fields even when there is no teosinte in the vicinity to cause contamination. He is of the opinion that the potentiali- ties for producing teosinte by recombination exist in many Mexican varieties. A well-planned program of maize-breeding under the direc- tion of Ing. Edmundo Taboado, Direccion de Agricultura, Mexico, D.F., is in progress at several stations. Ing. Eduardo Limon In charge of the Campo Experimental at Leon, Guanajuato, is one of the most enthusiastic of maize breeders. Because of the Mexican trip, I missed for the first time in twenty years, the usual summer pollinating season. However the work carried on by J. W. Cameron during my absence has re- sulted in several interesting developments. The most important of these is a study of knob numbers on the chromosomes of Guatemalan varieties. Two hundred varieties were grown and knob numbers determined for 162 of these. The’number varies from 1 to 16, and involves every previously encountered knob position in maize as well as two unusual positions on No. 10. Knob number is correlated with several other factors. Pubescent varieties had an average of 6.2 knobs as compared to 11.6 for non-pubescent types. Varieties with low knob numbers usually have tender brittle stalks which lodge easily; those with high numbers usually possess strong tough stalks. There Is a rela- tion between the altitude at which the corn was collected and knob number. Tentative averages based on the altitude data so far available are as follows: 500 meters 12.6 knobs 1000 it 10.7 it 1500 it 10.8 ii 2000 it 7.5 it 2500 it 5.5 i i 412 Finally^ types described on the basis of the general appearance of the ear as "Andean" proved to have a low number of knobs, 4.7, a3 compared to the population as a whole, 7.9. The^results are in general agreement with the hypothesis (Mangelsdorf and Reeves) that corn with knobless chromosomes was introduced from South America into Central America where it hybridized with Tripsacum to produce teosinte and new Tripsacum-contaminated varieties of maize with knobby chromosomes. The South American types apparently still persist in a relative state of purity at the higher altitudes in Guatemala. P. C. Mangelsdorf University of Illinois, Urbana, Illinois 1. The gene rt appears to be close to d. (chromosome 3). In a progeny of eight "plants (backcross repulsion phase), all the normal plants were rt and dwarf plants Rt. 2. The dwarf types reported in the 19^1 News Letter may be located in chromosome 3* at about 24 (assuming the chromosome reversed with cr at 0. 3. A leaf spotting has been discovered in one of our in- bred lines. It is a simple recessive to the normal. C. M. Woodworth University of Minnesota, University Farm, St.Paul, Minnesota 1. A new 3Ugary, located by Horovitz in chromosome 6, was sent to me. A test with su2 indicates these two genes are prob- ably alleles, although the test was not very clearcut. 2. Glossies - The third-leaf glossy, according to tests at that time, reported by Hayes as being linked with waxy (8$ recombination, Coop Letter April 1939)* is the same as the Coop, glossy 10, Coop number C37~110 (l) (x). This glossy 10 is different from Sprague’s glossy 10. 3. A group of unlinked genes is being tested for linkage in chromosome 6. C . R . Burnham 4. Further studies have been made with chromosomal inter- changes and the Minn. #13 smut resistant inbred line first reported by Saboe and Hayes, Jour. Amer. Soc. Agron. 33: ^°3t 470. The long arms of #3, #7, and #8 and the short arm of #o seem definitely to carry factors for smut reaction. Lewis C. Saboe 413 Missouri Botanical Garden* St. Louis* Missouri 1. Tripsacum. With Dr. Hugh Cutler a preliminary survey of the genus Tripsacum has been published (separates available on request). The most Important new fact turned up is^a Tripsacum indigenous to South America from the Amazon Basin to Colombia. The numerous specimens from that region have at least one unique character and cannot therefore be recent in- troductions as had previously been supposed. The genus is so complex that it will take a decade to work out a complete and detailed monograph. In the meantime we shall be grate!ul for viable seeds or for chromosome counts of any species of Tripsacum from known localities. 2. Races of Maize. Cutler’s collections of Mexican and Guatemalan maize have made it possible to begin another long- time project* the determination and description of the races of maize. While Sturtevant’s classification (dents* flints, pops* etc.) is adequate as a cataloguing device there is also need for at least a rough grouping indicating general relationships in somewhat the same way that anthropologists analyze human variation. For such a grouping it is necessary to know as much as possible about the entire plant; tassel and leaf as well as ear and grain. We have therefore built up an herbarium of as many corn varieties as possible* including with the ear* herbarium specimens of seedlings* leaves* and tassels and notes on the number of nodes above the ear* the height of the plant* etc. For a considerable number of our collections duplicate specimens have been prepared In St. Louis* Texas* and Cuba. In addition to Cutler’s collections we grew George Carter’s exten- sive collection of Indian varieties from the southwest and a few unusual varieties such as Louisiana Gourdseed. From an examination of the herbarium material the follow- ing characters were chosen a3 most indicative of general rela- tionship: row number; kernel width, length, and thickness; mid cob width; number of tassel branches; length of glume (tassel); percentage of condensed internodes in tassel; pedicel lengtn of pedicillate spikelet; percentage of sub-sessile pedicillate spikelets; length of sterile zone at base of tassel branches; pubescence of sheath. By the use of these criteria our Mexican and Guatemalan collections can be divided into at least three main races* Big Grains, Mexican Pyramidals, and small-seeded Tropical Flints. The Big Grains are big cobbed and big kerneled with more or less enlarged butts. While they may be flour or ilint they^ are characteristically more or less dented. The small-seeded Tropical Flints are not only exceedingly straight-rowed but the kernels are very uniform in diameter so that a row of them looks like a stack of pearl buttons seen from the side. They are all flints* have small cylindrical ears* and are prevail- ingly bright-colored. The Mexican Pyramidals are the common race in Mexico City and adjacent portions of the plateau. Im- portant to U.S. corn breeding because most of their distinguish 414 ing features, in a more or les3 diluted form, are found in cornbelt dents. They have a short pyramidal ear with long (often pointed) kernels. They are nearly all dents or semi- dents and the majority of them are white. They have few tassel branches and large glumes so that they are strikingly different from most other races and have been commented upon by Bonafous and Bukasov. The Indian corns of the southwest go into two races, the Pima-Papago and the Pueblo, the latter being closely allied to the Big Grains. Median values for representatives of these five races (and subraces) in our collections are as follows: Guate- Mexi- mala can Big Tropical Pueb- Pima- Pyra - Grain Flints lo Papago mi dal Mid-cob width 30 22 26 22 20 Kernel width 10 7 9 8 8 Kernel thickness 5 3 5 5 4 Kernel length 10 9 10 3 14 No. of tassel branches 20 21 18 10 4 Length of sterile zone 8 7 8 3 3 Percent condensed internodes 0 0 10 0 40 Percent sub-sessile spikelets 0 0 0 10 50 It will be seen that on the whole the Big Grains are at one extreme and the Mexican Pyramidais are at the other. It is also to be noted that the Pima-Papago race while similar to the Tropical Flints in cob-size and grain-size is far removed from them in all other characters. Collins (in Guernsey and Kidder 1921) was therefore in error in identifying the prehistoric Basketmaker corn (which is practically Identical with the modern Pima-Papago) with the Tropical Flints. 3. Southwestern races of maize. In the southwestern United States our collection of varieties is complete enough and the situation is so comparatively simple that we can gen- eralize more completely than in Central America. Southwestern maize goes in two races plus a few obvious recent admixtures and an extensive series of intermediates between the two ex- tremes, One race (the Pima-Papago) has been in the country a much longer time and is not now commonly grown by the Pueblo- dwelling Indians. The Pueblo race is the big-shanked, long-eared, usually bright colored maize which is commonly sold to tourists. While it may be either flour or flint it has a strong tendency to be at least slightly dented. Characteristically it has short internodes immediately above the node of the upper ear and its tillers are morphologically unlike stalk in height, tassel, and ear. It Is grown by all the Pueblo-dwelling Indians as well as 415 by the Navahos and Apaches. The Pima-Papago corn, though extensively grown, is from districts so remote that it is seldom seen in collections. It is small-grained and small-cobbed and either white or bright light yellow. It is small-shanked and ears often taper as much to the butt as to the tip. While the kernels are in rows, the sulci between them are scarcely apparent and the kernels have somewhat the appearance of tiles in a mosaic. Characteristical- ly the internodes of the main stem do not shorten above the ear and the tillers, in height, ear, and tassel are similar to the main stalk. It is grown by the Pima and the closely allied Papago and to a lesser extent by neighboring tribes. It is of peculiar interest because it3 ears are almost identical with those of the prehistoric Basketmaker Corn which according to dendrochronological reckoning appeared in the southwest about A.D. 300. Since everyone to whom we have shown the collection has asked whether our work gives evidence for or against Mangelsdorf and Reeve’s theory, it may be well to add that while in general it supports them, we have as yet no conclusive evidence for or against. It is already abundantly clear, however, that maize has had a complicated career in Central America. We will be grateful for viable seed of old or unusual varieties. Edgar Anderson University of Missouri, Columbia, Missouri 1. Comparison of Xray and Ultra-violet Mutations of A. The origin of the Xray and UV mutants compared in this study, and observation on their phenotypic effects, viability and re- action to Dt_, were given in the last News Letter. All three Xray mutants showed more or less reduction in gametophytic viability and were zygotically lethal; all four UV mutants were fully viable, regularly transmitted through male and female germ cells, and readily established as homozygous recessives. This suggests that the Xray mutants are probably deficien- cies too small for cytological Identification and too slight in effect to be lethal in haplophase, but it leaves open the possi- bility that they are alleles of a with lowered viability. With losses too small for cytological detection, the only proof of deficiency is genetic evidence of the loss of associ- ated loci. McClintock's study of Bm ring-chromosomes showed the possibility of identifying loci in a deficiency through their effects upon tissue within a sector made homozygous deficient by loss or modification of the covering ring. We were fortunately able to obtain a ring including the A 416 locus. The origin of this ring is an interesting story in it- self, but it will not be included here. The ring carries the gene A^, and its behavior is similar to that described by McClintock. It is maintained in a stock otherwise homozygous for a. Crossed on standard a stocks it gives sectors of a tis- sue in both the aleurone and the plant. Ring bearing plants otherwise homozygous for the Xray mutant were obtained for comparison by crossing and back- crossing as follows: (1) a^ aP x a a A*3-ring (2) a^ aP x aĵ a A^-ring (3) aX aP x a^ a^ A*3-ring Cross (l) gives mostly pale and colorless seeds,, but also a considerable number of colored seeds, all of which are mosaic for pale or colorless. These are the ring-bearing individuals. Cross (2) yields mosaic colored seeds similarly, but among them there is included a new class in which the mosaic regions are of shriveled, degenerate tissue. These are the a^ A^-ring individuals. In cross (5) this class comprises nearly half of the mosaic seeds. The remainder (without degenerate tissue) are all phenotypically aP in the mosaic regions, and represent the â - aP A*3-ring class. The sectors produced in plants grown from these two types of seed are very different. In the plants with aP the sectors are of wholly normal tissue, lacking only the anthocyanin char- acteristic of A^. They include both large and small sectors. In the plants homozygous for a^ the sectors are small, and many show reduced growth leading to distorted development of the plant. Their most conspicuous feature Is lack of chlorophyll. These sectors, whenever they occur in regions in which antho- cyanin develops, show normal anthocyanin. In other words, they do not show the loss of A*3. Very rarely a sector is found with loss of anthocyanin and with no loss of chlorophyll. In four cases we have found narrow sectors showing loss of both antho- cyanin and chlorophyll, and each of these occurred as a second- ary sector within a larger sector showing loss of chlorophyll without loss of anthocyanin. \rh We interpret this to mean that the mutant a^ represents ths loss of not only the A factor but also of a separable fac- tor essential to chlorophyll development, and possibly of another essential to tissue survival. If the sectors showing loss of chlorophyll without loss of anthocyanin have the genetic constitution Indicated by their phenotype, the separable viability factor must be assumed. The absence of primary sec- tors showing loss of both chlorophyll and anthocyanin would indicate that simultaneous loss of the two factors is lethal, while the occurrence of sectors deficient for both as a result 417 of consecutive losses would show that the lethal effect is not due merely to deficiency of these two factors. It would there- fore have to he ascribed to a separable portion of the ring which is regularly eliminated when A and the chlorophyll fac- tors are lost simultaneously. It is possible however that the sectors are in fact deficient for Pfi. Their anthocyanln pig- mentation Is normal, but since the sectors are small it is pos- sible that this may be a result of diffusion from the neighbor- ing non-deficient tissue. If this is true, the assumption of a viability factor separable from A and the chlorophyll factor is not required. The description given above for a-^ a-^-Ring plants applies also to the compounds a-X̂ a,Xl-Ring and a / ^ aX'-'-Ring. This shows that axl and ax6 also lack the associated factor or factors. We have not yet succeeded in producing a plant which could be proven to be homozygous a,Xl aXI A^-ring or aX° Ah-ring. It is possible that both aX-*- and aX° Involve more loss^ than a,X •. aXb is distinctly lower in male transmission than a 7 ^ , while aXI. is distinct from both In having visibly defective pollen and no male transmission. The most extreme mutant, a , reduces crossing-over between A and E_t, though there is no visible indi- cation of deficiency in the pachytene chromosome. The results indicate that the apparent mutations of A in- duced by Xray treatment are In fact minute deficiencies. The original series of Xray-induced A-losses from which the mutants were selected included, In addition to obvious extreme defi- ciencies, several less defective plants with segregating pollen not wholly aborted but distinctly sub-normal in development. a-XI was a representative of this class. The A-losses with normally developed and partially functional pollen, a ̂ and apparently represent simply the extreme of the continuous series of intercalary deficiencies of varying length Induced by Xray treatment. On the contrary, the UV mutants, a^, af^', and a^"^, sim- ilarly tested with the ring-chromosome, behave precisely as do the standard alleles, aP and a, and their sectors are pheno- typically identical with those of standard a,. The UV mutants, unlike the X-ray mutants, appear in the Fi from treated pollen as a class distinct from the deficiencies produced by the treatment. The series of UV-induced A-losses included, in addition to the three mutant a ’s and the inter- mediate allele A^ , a large number of extreme deficiencies with distinctly defective growth and aborted pollen, but none of the intermediate type with subnormal pollen. This may be due to the rarity of intercalary deficiencies induced by this agent. Although It is reasonable to assume that intercalary deficien- cies may sometimes be induced by UV (since translocations are), it is clear that the UV mutations are much too frequent to be accounted for in the way suggested above for the Xray mutations. 418 If the UV mutants are deficiencies they are def d ii cf if ee nr cen it e s or od fe r a. They show no difference from t se tn at n di an r dt h ae i er x -failure to mutate under the influe p nr ce ev i oo fu s Dl ty . st Aa st ed (News Letter 1941: ^ 5 ) , this is not i ng c oe nv vi id ne cn -ce against intragenic mutation. L. J. Stadler and Herschel Roman 2. Translocations involving B chromoso c ma et si .o ns E ib ge ht tw e te rn a nA s la on -d B chromosomes have been ob b te aa ir ni en dg fp ro ol ml e Bn - treated with Xrays. The A chromosome of six of points determined, as follows: Cytological Position Translocation A chromosome B chromosome Tl-B S .1 heterochromatin T2-B S .2-.9 junction* T4-B s .2 j unction T6-B s (dividing nuc- leolar organ- izing body) heterochromatin? T7a-B L .9-1.0 junction T7h-B L .39 euchromatin *This is the junction of the euchromatic region and the large heterochromatic region. All of these except T7a-B were tested t fr oa rn s mm ai ls es i ao nn d. feT mh ae l e female transmission was quite no m ra ml ae l t or ua tn s tm hi es sion was distinctly low. For h e et xe ar mo pz ly eg ,o us a pf lo ^r n T2-B in which the translocation V w4 a s a mnd a rkt ehe d bn yor mal chromosome by v4, when used as the male parent on homozygous v4, gave bO T Vh 4e r :e 1i 6s 4 c vo 4n Jsi id e sr ®a eb Jl ?e ;i rc ir gso :s ns .i ng over between b reak aa ng de ts ho e t ph oa it n t th oe i frequency with which the t ra tn rs am ni st lt oe cd a tii os n le iss 3 than the ratio indicates. wi St ih m iT l4 a- rB , c ri on s sw eh si ch the translocation was mar n xo er dm a bl y chro am no ds o tm he e 4 by su, when crossed on s su u. gaS vi en c 2e p yv e Sr uy : li (t yt fle, if any, crossing over a on cd c ut rh se bp eo ti wn et e no f b ub reakage the ratio of Su : se sn ut s p ra o bc al bo ls ye ra ep pp rr eo -ximation of the frequency with which T4-b is transmitted. Evidence that a heterozygous A-B translocat a is o nt h we h em na l ue s ep da rent produces hypo- and hyperplo g ie ds t Fe pd pt lh aa nt t st h se u gl -ow male transmission was a r d ei ss uj lu tn c ot fi o nn o ni -n the second microspore divis p il oa nn .t s Hf yr po em r pT ll o-B i, d T2-B, T4-B, T7a-B, and T7b- c By t wo el ro eg i ic da el nl ty i la in ed d ^w ere found to contain the he l to ec ra ot zi yo gn o up sl u ts r aa nn s extra translocation chromos e ox mt er .a ̂ch Thr uo sm os to hm e e must have resulted from non- a dt i sm je ui no cs ti is o no r e ie tl ns ee rw here. In every case the extra chromosome 419 was the translocation chromosome which possessed the B chromo- some centromere. The production of hypoploids was demonstrated when plants heterozygous for an A-B translocation and carrying only dom- inant factors were crossed on plants carrying appropriate recessives. The data from this type of cross are given in the following table. Frequency of recessives Crosses appearing in F \ Per Cent Su su x T4-B/normal, Su 3u 52 su/425 25* su x T4-B/normal, Su Su 51 su/92 5^ 02 £l x T7b-B/normal, 02 02 Gl Gl 0 £2/65 0 21 £1/65 55 Li LL 01 gl x T7b-B/normal, 6 1± gl/42 23* LL Li oi gi *These values have been corrected for the fact that the female parent was heterozygous rather than homozygous recessive. The appearance of the recessive character in the F]_ is due to the loss of the translocation chromosome bearing the factor for the corresponding dominant. Since Gl is nearer the end of the long arm of chromosome 7 than 02, the loss of Gl without the loss of 02 must mean that the absent chromosome is the one possessing the B chromosome centromere. Proof that non-disjunction occurs at the second microspore division was obtained from a cross using a hyperploid plant from T2-B as the male parent. Twenty-three F]_ plants were examined cytologically. Of the twenty-three, twelve were hyperloid like the male parent; seven were euploid, heterozygous for the translocation; and four were euploid, homozygous normal. The occurrence of twelve hyperploid plants, which could have resulted only from non-disjunction, and the absence of other classes that would be expected with the same frequency from non-disjunction elsewhere show that non-disjunction occurs only at the second microspore division. The frequency with which non-disjunction occurs may be roughly estimated from the data in the table demonstrating hypoploidy. The maximum frequency with which the recessive may appear is 25$ (corresponding to 100$ non-disjunction) if the hypoploid plants are viable (as they certainly are in the case of T7b-B and probably also in T^-B). The fact that the ob~̂ served frequencies equal and exceed this value cannot be taken too seriously since these data were obtained from a limited series of crosses and may be effected by the presence of asso- ciated transmission factors. It is known from cytological 420 evidence that the frequency of non-disjunction is not 100$. But the data do suggest a very high frequency and further experi- ments to determine this with accuracy in each of the A-B trans- locations are in progress. Will non-disjunction account for the anomalous male trans- mission of the intact B chromosome? The combined data of Longley and Randolph, from a cross of a IB male on a OB female, gave 108 plants with no B chromosomes, 35 with 1, 20 with 2, and 2 with 3 B chromosomes. We should expect, from 50$ non- disjunction, 103 plants with no B«s, 4l with 1, 21 with 2, and none with 3 B chromosomes. The observed 3 B chromosome plants may be accounted for in other ways. The close fit indicates that the mechanism for the aberrant male transmission of A-B translocations is identical with that of the Intact B cnromo- some. Can we localize the cause of non-disjunction within the B chromosome? The heterochromatic region may be excluded as a factor in non-disjunction for in T7b-B the chromosome under- going non-disjunction does not contain this region. Further- more, non-disjunction is not related merely to the shortness of the chromosome for in the case of Tl-B the translocation chromosome undergoing non-disjunction is longer than the normally behaving short A chromosomes. Consequently, the cause of non-disjunction is related to the position or the special nature of the B chromosome centromere or to some factor in the pro ximal portion of the euchromatic region of the chromosome. 3. Some uses of A-B translocations. The B chromosome pro- vides a centromere to which specific segments of A chromatin may be translocated. The exceptional behavior of the resultant chromosome in the second microspore division provides a mecnan- ism for the accumulation of this chromosome for various cytogenetic problems In which duplications are useful. One application of this, now in progress, is a study of the effect of accumulation on the phenotype of recessive and intermediate alleles, using T2-B for a comparison of B, Bv , and b in various doses. The fact that A-B translocations produce functional gametes deficient for as much as a whole arm of an A chromosome pro- vides a tool for the location of recessive genes in the physi- cal chromosome in a single generation. One would simply cross known A-B translocations on the recessive in question, locus of this gene is in the translocation chromosome with the B centromere, the recessive phenotype will appear In the F]_, For example, if the recessive is located in the distal four- fifths of the short arm of chromosome 4, it will appear in the F]_ of a cross by T4-B. The results summarized in the table place Su. In this region. Likewise G1 and Ij[ are in the distal two-thirds of the long arm of chromosome 7, whereas 02_ is not in this segment. An extensive planting for new A-B transloca- tions involving different segments of the A chromosomes is planned for this summer. Herschel Roman 421 4. The Anthocyanin Pigments of Corn. According to Sando et al, the plant pigment of purple corn (A B PI. Rr ) is chrysan- themin. The anthocyanin pigments present in other types have not previously been reported. The anthocyanins which occur most commonly as flower color pigments (glycosides of pelargonidin, cyanidin, delphinidin, peonidin, malvidin and petunidin) may be identified by simple qualitative tests outlined by Robinson and Robinson. The reac- tions of many less commonly occurring anthocyanins and of some synthetic anthocyanins not known to occur naturally have been summarized by Karrer. Robinson's qualitative tests have been applied to the pig- ments extracted from numerous genetic types of corn.^ Although some of the pigments were identifiable with the qualitative tests, there were several which proved to be distinctly differ- ent in their reactions from the common flower pigments listed above. An F2 of the hybrid a p r b p ! R g x A P r B P l R r was^closely examined for color variations. In addition to the familiar plant color types expected from this cross, there were various minor modifications which have not previously been analyzed genetically. Plant material was taken from many of these plants for analysis, and all of the plants were s e l f -fertilized. The "A" type plants (A B Pi) in this hybrid population fall into three fairly distinct groups: (l) deep bluish purpl 2 e, ( ) deep reddish purple (maroon) and (3 ) light, distinctly red- dish purple (dilute). The anthocyanins extracted from these plants included typical pelargonidin as well as typical chrysanthemin, and also in several cases pigments giving a typical reaction. The pigment differences are not always evi- dent from the external appearance of the plant. Both chrysan- themin and pelargonidin are found among the deep bluish purple plants and among the maroon plants, but chrysanthemin is not found in the ’dilute" class. In F-z, pure breeding families of the above described types were established. One deep bluish-purple family contained typical chrysanthemin. One deep bluish purple, indistinguish- able from the chrysanthemin family except by anther color, contained a pigment which differed only slightly in reactions from pelargonidin 3-monoside, and one family of reddish purple (maroon) had pigment apparently identical to that of the deep purple pelargonidin type. A pure breeding "dilute xamily showed typical pelargonidin 3-monoside reactions. The pigment of "B" type plants (A B pi) showed reactions not typical of any of the commonly occurring anthocyanin types. Although there was variation in intensity of pigmentation com- parable to that among the "A" type plants, no differences in the pigment of the different ”Br’ type plants have been estab- lished. 422 The variation in intensity of the ”E M type (aBFl) Plants is correlated, at least to a large extent, with that of "A" type plants. In families with "Am type plants mostly deep purple, the "E" types were mostly deep brown and in families of "dilute” pigmentation it wa3 difficult to distinguish a B PI from a B PI plants until the plants were nearly mature. The pure breeding pelargonidin families of this stock were recessive pr but in many plants of this hybrid the Pr separa- tion was doubtful. Therefore tests were made on different hybrids with positive Pr separation to establish this relation. In the first planting, the Pr plants, (6 in number) all con- tained chrysanthemin and the pr plants (8 in number) pelargoni- din 3-monoside. In tests on the Pr and pr plants from six ears of the progeny of this family (self-fertilized or back-crossed) the same results were obtained. The pigment was found to be the same in all parts of the plant, including roots, coleoptile, sheath, husks, cob and aleurone. Analyses have been made of pigments characteristic of other A alleles, in plants with B and PI. Ab gives chrysan- themin indistinguishable from that of A plants of the same cul- ture. Standard a'P, several mutant ab,s (by spontaneous muta- tion from Ab ), and Alt:, (an ultraviolet mutant of A), all give mixtures of anthocyanin and flavonol in varying proportions. The anthocyanin in these mixtures, however, is distinct from that produced by A and Ab , and resembles in some reactions the pigments of sun-red plants. J, E. McClary 5. Experiments on Gene Action in Anthocyanin Synthesis. In those genotypes which normally produce anthocyanin in the root, excised roots cultured on media containing glucose and mineral nutrients produce anthocyanin abundantly. Anthocyanin there- fore may be synthesized by the cell from externally supplied glucose, without the intercession of other substances derived from the overground parts of the plant. The genes essential for root color in the dark are A (or AD), Ap, PI, and a suit- able R allele (Rch, rch, and some but not all Rr,s and rr,s). B is not essential and does not replace Rr . It may be possible to learn something of the course of synthesis of anthocyanin, and of the role of various genes ai- fecting it, by physiological experiments with excised tissues, testing the effects of postulated intermediates between glucose and anthocyanin, of specific enzyme inhibitors, of diffusible substances extracted from plants of contrasting genotype, etc. Experiments with intermediates supplied in place of glu- cose cannot well be made with excised root-tip cultures, be- cause the addition of some glucose or fructose is necessary to keep the roots growing. An intermediate would have to replace glucose in general metabolism as well as in anthocyanin 423 synthesis to give positive results. Minimal quantities of sugar will maintain slow growth with little or no anthocyanin production, and experiments may he made with Intermediates added to increase the anthocyanin yield. A more satisfactory technique is to use sections of mesocotyl or leaf blade from young seedlings, since cell divi- sion is not a factor and since differentiated cells capable of anthocyanin production are present from the start. ^These sec- tions remain alive for several days in bulfer solutions, dilute salt solutions, or pure water. In suitable genotypes, they fail to produce anthocyanin unless sugar is added, while with added glucose or fructose they produce anthocyanin abundantly. Although these sections may contain reserve carbohydrate which may be used in the synthesis of anthocyanin, they cannot com- plete the synthesis without something which they obtain from added glucose. Leaf blades from mature plants also serve very well in C r stocks (with A b PI), and quite well in RGh. Anthocyanin is produced poorly in mature leaf tissues with the best of the R and rr alelles tested, and not at all with some. Mature leaves are convenient material, especially for producing the quanti- ties of pigment required for chemical analysis. Several preliminary experiments of this type were performed this winter, and some of the results are summarized below. Galactose, which does not support the growth of excised root tips, may be substituted for glucose in the production of anthocyanin in leaf or mesocotyl tissue. On the contrary, mannose, 1 -sorbose, and 1 -rhamnose give no anthocyanin. The pentoses, xylose and lyxose, give a good yield oi anthocyanin, while arabinose (both d- and 1 - forms) and ribose fail. Some modifications of the Cp and C5 groups in the glucose molecule may be made without preventing the production 02 anthocyanin. Sorbitol and glucuronic acid yield anthocyanin; -methyl-glucoside and gluconic acid do not. The trioses, glyceraldehyde and dihydroxyacetone, in phosphorylated form, are produced from glucose in the normal course of respiration. Either glyceraldehyde or dihydroxy-^ acetone (unphosphorylated), supplied In place of glucose, will permit the production of some anthocyanin, more in the case 02 glyceraldehyde than of dihydroxyacetone. Various specific enzyme inhibitors or poisons have been supplied over a range of concentration extending to the toxic limit, without producing a distinct reduction in the yield of anthocyanin from glucose. These include cyanide, azide, iodoacetate, fluoride, malonic acid, urethane and maleic acid. Certain other inhibitors show possible effects which are still 424 under study. The only substance which in catalytic concentra- tions shows inhibition of the production of anthocyanin from glucose, in the trials made so far, is 2-4-dinitrophenol. This is a well-known stimulant of respiration and glycolysis, and may reduce anthocyanin synthesis competitively by diverting glucose to other channels. At concentrations of the order of 10~J molar it inhibits anthocyanin production, and at lower concentrations it reduces materially the quantity of anthocya- nin produced. A possible hypothesis is that anthocyanin is produced by condensation of two phenol derivatives, related to phloroglu- cinol and catechol, with a 3C unit derived from glyceraldehyde. The effect of A would be a reduction in the 3C unit, which might occur either before or after the condensation. If the reduced 3C substance in A stocks were glyceraldehyde itself, it might be possible to produce anthocyanin in tissue lacking the A gene by supplying this substance. This was tried, unsuccess- fully, with a, aP, Alt:, and a£. Similar trials with dihydroxy- acetone, glycerol, and hydroxypyruvic aldehyde (all of which produce some anthocyanin in A tissue) also failed. Experiments in this direction with various 3C substances are being contin- ued, together with analogous experiments with catechol deriva- tives and 6C-3C compounds in relation to the Pr effect. The experiments mentioned are of course merely exploratory trials, made chiefly to test the feasibility of the general approach and to determine which aspects, if any, have suffi- cient promise to justify more intensive study. Obviously, neither the positive nor the negative effects of specific sub- stances upon anthocyanin production may be interpreted in terms of the place of these substances in biosynthesis, without care- ful 3tudy of their other physiological effects. L. J. Stadler United States Department of Agriculture and Iowa State College, Ames, Iowa Backcros3 data indicating the order of the genes gs2, B and are given below. 0 1 2 1 - 2 + B lg 107 104 11 0 46 38 3 1 gs2 + + 211 11 84 4 310 The linear order and map distances are: gs2 4.8 B 28.4 lg. G. F. Sprague 425 University of Wisconsin, Madison, Wisconsin Below are given the results of a backcros3 test G o wl id te hn 2 against translocation 3~7b. In the lig e ha tr l oi fe r o ur re port (M.G.C. N.L., 5-23-37, P b .? y lin tk he ad t w £i 2t h w ad s] pt oh se s iindication is that £ 5 2 is in chromosom, e Chromosome 7 , however, is not excluded. T+ Tg2 ++ +g2 KfL- 139 19 19 160 337 T3-7b Percent recombination r 11.3 R. A. Brink and D. C. Arny 426 III. MAIZE PUBLICATIONS There is presented here a list of papers on maize, a n p ri on bc ao bm lp yl ete one. No long search of the literature has bee ma nd e. Fraser did a better job last year. R. A. Emerson Abbe, Ernst C., L. F. Randolph, and John Einset - Th m ee n dt ea vl e lr oe pl -ationship between shoot apex and growth patter o nf leaf blade in diploid maize. Amer. Jour. Bot. 23: 773-734. 1941. and B. 0. Phinney - The action of the gene dwar i fn 1t he outogeny of the stem of maize. Abst. in Genetics 27, p. 129. 1942. Anderson, E. G. - Translocations in maize involving the sho a rr tm of chromosome 1. Genetics 26: 452-459. 1941. Bair, R. A. and W. E. Loomis - The germination of maize pollen. Science 94: 168. 1941. Blanchard, Ralph A., John H. Bigger and Ralph 0. Snell R ie ns gistance of corn strains to the corn ear worm. Jour. Amer. Soc. Agron. 55: 544-550. 1941. Burnham, C. R. - Cytogenetic studies of a case of pollen ab t oi ro -n in maize. Genetics 26: 460-463. 1941. Clark, Frances J. - Preliminary investigations in Ze t ah e m ayg se ,r m oi fn ation capacity of pollen with aberrant nuclei. Abst. in Genetics 27, p. 157. 1942. Cunningham, J. C. - Maize bibliography for the years 1 9 15 96 1, 7 i tn oc lusive. Contributions. Iowa Corn Research Institute 2: 1-564. 1941. Cutler, Hugh C. and Edgar Anderson - A preliminary surve th ye ofg enus Tripsacum. Ann. Mo. Bot. Card. 23: 249“2o9. 1941. Jenkins, M. T. - The segregation of genes affecting yiel g dr a oi fn in maize. Abst. in Proc. Seventh Intern. Gen. Cong., p. 163. 1941 (1959) Jones, Donald F. - Somatic segregation. Bot. Rev. 7: 291-507. 1941. _______________ - Segmental exchange in somatic cells of maize. Proc. Intern. Gen. Cong. p. 170. 1941 (1959). 427 Khankhoje, P. - Un nuevo e intersante hibrid 3 o de ma( iZ ze a t um ra iy ic att au nicata) con polen de teocintle (Euc m he lx al ec na an a Schrad.) Mem. Acad. Nacion. Cienc. Antonio Alzate'1 55: 83_94. 1940. Lindstrom, E. W. - Analysis of modern maize breeding a n pd r im ne ct ih po ld es . Proc. Seventh Intern. Gen. Cong. p 1 p9 .6 191“ . 1941 (1939) ________________ - Inheritance of seed longevity in ~ m aize b ir ne -ds and hybrids. Abst. in Genetics 27, p. 154. 1942. Longley, A. E. - Chromosome morphology in maize and its rela- tives. Bot. Rev. 7: 263-289. 1941. ______________ - Knob positions on teosinte chromosomes. Jour. Agric. Res. 62: 401-413. 1941. Mangelsdorf, P. C. - The origin of maize. Abst. in Proc S .eventh Intern. Gen. Cong. p. 209. 1941 (1939). McClintock, Barbara - The association of mutants with d he of mi oc zi ye gn oc ui se s in Zea mays. Genetics 26: 542-571. 1941. Randolph, L. F. - An evaluation of Induced polyploid m ye t ah so d a o ^f breeding crop plants. Amer. Nat. 19 74 51 :. 34( -I 3nc -l pu . des a discussion of polyploid maize and teosinte. Ed.) _______________ - Genetic characteristics of the B chromosomes in maize. Genetics 26: 608-6 31. 1941. _______________ - The influence of heterozygosis on fe a rn td i lv ii tg yor in autotretaploid maize. Abst. in Genetics 27, p. 163. 1942. Rhoades, M. M. - On the high mutation rate of the m a ai z ae l li en ld eu c ie nd by the Dt gene. Proc. Seventh Internal. Gen. Cong. pp. 247, 24"o. 1941 (1939). ______________ - Different rates of crossing over In m f ae lm ea l ae n dgametes of maize. Jour. Amer. Soc. Agron. 33: 603-615. 1941. Roberts, E. and Irvin R. Horner. Causes of prefe h ri eb ni ct ee sd eb xy - animals for certain inbred strains of corn J .o ur. Amer. Soc. Agron. 33: 448-453. 1941. Roberts, Lewis M. - The effects of translocations on I n g rZ oe wa t hm ays. Abst. in Genetics 27, p. 166. 1942. Roman, Herschel - Translocations involving "3" chromosom m ea si ze I. n Abst. in Genetics 27, p. 167. 1942. 428 Rosenquist, C. E. - The effect of tillers in cor d ne ve ul po op nm e tn ht e of the main stalk. Jour. Amer. Soc. Agron. 33: 913-917. 1941. Saboe, Lewis C. and H. K. Hayes - Genetic studies to o f sm ru et a ca tn id o nsto firing in maize by means of chrom t or sa on ms al lo cations. Jour. Amer. Soc. Agron. 33: 463-470. 1941. Shafer, John, Jr. and R. G. Wiggans - Correlation m a ot ft e tr o tw ai lt h d rg yrain yield in maize. Jour. Amer. Soc. Agron. 33: 927-932.' 1941. Singleton, W. R. - Hybrid vigor and its utiliz c ao tr in o nb r ie ne d si wn eg e. t Abst. in Proc, Seventh Intern, Gen. Cong pp. 26 .4, 265. 1941 (1939). ________________ - Hybrid vigor and its utilization in sweet corn breeding. Amer. Nat. 75: 43-60. 194l. Sprague, G. F. and A. A. Bryan - The segregatio fe nc t oi fn g g eny ei se ld a fp -repotency, lodging, and disease r i en s ist ancF e-x and Fu lines of corn. Jour. Amer. Soc. Agron. 33: 207-214. 1941. Stadler, L. J. and Fred M. Uber - Genetic effe v ci to sl e ot f r ua ld ti ra at -ion in maize. IV. Comparison of mono m ca hti rc o -radiations. Genetics 27: 34-113. 1942. Tavcar, A. - Inheritance of 2-, , 4- and 6-articula w th eo rl ls ea fin Zea mays L. Abst. in Proc. Seventh Intern. Gen. Gong. pp. 295, 296. 1941 (1939). 429 IV. Inventory of Seed Stocks Propagated in 1940 and 1941 A complete list of all Coop, stocks on hand at the close of the 1939 season appeared in the 1940 News Letter. The sym- bol (x) = selfed and # = sib crossed. 1940 Co 40-1 and 2 (x) Inbred I (U.S. 204) Pwr Y A b pi, also pol- linated with y Hadjinov's gl5, may seg. vx (9b); may seg. pr yga (88); Pwr Y cr "white stripe", may seg, wx pg2 lgx (95); gl4, may seg. y pr c sh wx ws (llS); may seg. y wx B PI f Hadjinov's gl8 (101); seg. at, may seg. y I? si ts2 br f bv (107); pr v3 , may seg. su (61); lg B/A/Pr/ y pl/C Rgg/bmx Sx , may seg. vx (65); Pwr, may seg. y pr Rgg RnJ? su B PI lgx g d7 vx (115); suam? ba2, may seg. y pr PI vx f? lgx (112); Y rt, may seg. pr PI dx bl? (124); Pwr Y fx pk? skx , may seg. msx dx (74); Y A b PI vb, may seg. P vx (109); P a sh wx f lgx , may seg. su (7 1 ); ws2?, may seg. y pr li g (1 1 9 ); sh pk, may seg. y lgx vx or lx (64); may seg. pr su wx? pga (94); y a C r pr wx, may seg. ysx (116); wx? may seg. y Bn? anx v6 dx crx (3l); P a br f, may seg. bm2 nl2 wx (123); may seg. dx3 dD (114); A B pi Rg Lg3 ds, may seg. y Bn? anx (129); 34 ears " 40-3 and 4 (x) Inbred II (West Branch) Y A b pi, also pol- linated with Pwr Y cr "white stripe", may seg. wx pg2 lgx (95); lg B/A/Pr/y pl/C/Rgg/bmx Sx , may seg. vx (69); Y rt, may seg. pr PI dx bl? (124); may seg. pr su pga (94); Pr, may seg. P pg g (65); 14 ears. " 40~5 and 6 (x) Dutton's Flint Inbred Y, also pollinated with P^, may seg. y pr Rgg Rn^? su B PI lg* g d7 vx (115); Y rt also Rg, may seg. pr PI dx bl? (124); Pvr Y fx pk? skx , may seg. msx dx (74); Y crx , may seg. Bn? v6 dx (82); "Deep Y" lg gl4, may seg. vx bmx (103); lg B/A/Pr/y pl/C/Rgg/ bmx Sx , may seg. vx (69); seg. sk, may seg. Pwr y dx blx vx crx (84); sh pk, may seg. y lgx vx or lx (64); f, may seg. y wx B PI Hadjinov's gl8 (101); Y wx?, may seg. pr su ara (93); 19 ears 40-*7 (x) P2 involving pwr Y Pr wx , may seg. y g a ; 3 ears 40-•3 (x) F2 involving P sk, may seg. ’'x ^gx' 4 ears 40-•9 (x) " n pwr Y y Pr su sp?; 4 ears 40--10 (x) f 2 pwr Y zb4; 3 ears 40- (x) M If pwr Y Rmb) may seg. j; 1 ear 40- (x) It 11 pwr Y y R S t Pr; 1 ear 40--13 (x) II it pwr Y y A C R n J Pr w11 x?pwr ; 5 ears 40--14 (x) II Y y Rgg Pr; 3 ears 40-■15 (x) II 11 pwr p V V Y y A C Rr§ Pr su ; 4 ears 430 11—1—1 1OJ -1 Co 40-16 (x) involving pwr y v7-striped; 5 ears M Fx ) It 2c- i 40-17 ( Pvr Y o B vx ; 5 ears I x) I it40-18 ( P Y aP B PI, seg. b pi; 5 ears I 40-19 ('x) It i i pwr y y vx? vl3; 4 ears I 40-20 (’x ) I i pwr y fs; 5 ears I 40-21 (x ) 1 i i Pwr Y y zb4 br f bm2 vx?; 5 ears I 40-22 (tx ) 1 it pwr y A b Ig g!2 ts v4, seg. PI; 4 ears I 40-25 ( 1 i;*) Pwr Y y A b pi vs3 lg gl2; 4 ears I 40-24 (X I i Pwr Y y A b pi lg gl2 fl v4;5 ears If 1 it40-25 1x) Pwr Y y d lg2, seg. anx , may seg. pm; 5 ears I 40-26 (x) " it Pwr Y y d a lg2, may seg. ts4; 5 ears 1 I it40-27 <' x ) Pwr Y y sh vx gl4 vx ; 5 ears it 40-23 (X )1 " ti pwr Y yg2 sh vx gl4 lg; 5 ears I 40-29 M Y fs; 2 ears 40-45 \ n t )x < Y y zb4 br f bm2 vx?; 4 earsIt 40-46 ( X (\ ,r it Y y y ? vs3 lg g!2: 5 ears It ( X ,\ It it40-47 Y y lg gl2 fl v4; 4 earst 40-43 (X _\ It it PwbY d lg2, may seg. pm; fev seeds It t t 40-49 ( X '1 » Y yg2 sh vx gl4 lg; 4 ears 40-50 (x \ t it Y y vx gl4 vx ; 5 ears It it40-51 (x!) " Y y "brovn stripe", seg. B PI F, may seg. msll ar-like stripe; 4 ears t 40-52 (x t) f 5 Inbred I and Pvr Y vx g4; also crossed vith Y vx g4 (59); H ears It (x i40-53 ) " Inbred I and Pwr Y y ra si, also crossed vith Y y ra si (56); 14 ears I 40-54 (x; i) " Inbred I and Pvr Y bm3, also cross- ed vith Y bm3 (57); 15 ears I n40-55 *(x;) " Inbred I and Pwr Y vx g4, also crossed vith Y vx g4 (53) and Y vx g4 (59); 14 ears If 40-56 ) and #F-x" Inbred II and Y y ra si; 13 ears If I!40-57 ( X ) " Inbred II and Pvr Y bm3, also crossed vith Y bm3 (54); 20 ears 431 Co 40-53 U) and #F^ involving Inbred II and Y wx g4, also crossed with Y wx g4 (52) and Y vx g4 (55); 15 ears " 40-59 (x) F-z involving Inbred II and Y vx g4, also crossed with Y vx g4 (52); 12 ears M 40-60 (x) y, may seg. g5 lx , (freezing injury, poor germ- ination); 1 ear " 40-61 (x) pr v5, seg. su, also pollinated with Inbred I (1) and Inbred II (5) and recip- rocally with Inbred I (l); 6 ears " 40-62 (x) Pw y, seg. mslS bm lgx , may seg. pgx or lx , also pollinated with Inbred I (l and 2 ); 5 ears " 40-65 (x) and # gl, seg. Wh slx , also pollinated with In- bred II (5); 4 ears " 40-64 (x) and # sh pk, seg. y lgx, may seg. vx or lx , also crossed onto Inbred 1 (l) and Dutton's Flint Inbred (5); 5 ears " 40-65 (x) and # Pr g, seg. P pg, also pollinated with In- bred II (5) and reciprocally with Inbred II (4); 6 ears " 40-66 (x) y r g, may seg. pr su 1 2, also pollinated with Inbred I (l); 5 ears ,r 40-67 (x) Seg. Pr pr msx, may seg. pg? pb? zb? and usually completely sterile plants with necrotic leaves, also pollinated with Inbred I (l), Inbred II (5) and y +/po (1 2 1 ); 7 ears " 40-68 (x) Seg. y R3t Pr, may seg. lx msx , also pollinated with Inbred I tl and 2) and Inbred II (5); 10 ears ” 40-69 (x) and # lg B/A/Pr/y pl/C/RgS/bm Sx , may seg. vx , also pollinated with Inbred I (2) and reciprocally with Inbred I (1), Inbred II (5) and Dutton's Flint Inbred (5); 9 ears " 40-70 (x) and | y a C R pr in j lg, also pollinated with Inbred I (l); 8 ears " 40-71 (x) and # P a sh wx f, seg. su lgx , also pollinated with Inbred I (l) and Inbred II (5) and reciprocally with Inbred I (l and 2 ); 10 ears M 40-72 P a sh wx su lg f (freezing injury, poor germina- tion); 4 ears " 40-75 and # a B PI lg v4, seg. y ts; 7 ears " 40-74 Pvr Y pk?, seg. skx, msx , may seg. dx fx , also pollinated with Inbrea I (2) and reciprocally with Inbred I (l) and Dutton’s Flint Inbred (5); 5 ears M 40-75 su, seg. y sh, may seg. vl4 d5 wx ; 2 ears " 40-76 and # P A B pi sh, seg. crx wx?, may seg. lo; 5 ears 432 and # Pr, seg. sh Ts , may seg. v3 dx> also pol- linated with Inbred I (l and 2), (freezing injury, poor germina- tion); 10 ears " 40-78 and if Y, seg. u flx vx crx , may seg. dx v8, also pollinated with Inbred I (l) and Inbred II (3); 12 ears " 40-79 (x) y su, seg.• ffxx>, may seg. dx v3, also pollinated with Inbred I (2), (freezing in- jury, poor germination); 2 ears " 40-80 Y, seg. su flx vx, may seg. v8 dx , also pollin- ated with Inbred I (2) and Inbred II (3); 8 ears " 40-31 wx?, seg. pwr ■ Bn? dx anx , may seg. v6 crx , also pollinated with Inbred I (2) and reciprocally with Inbred I (2); 10 ears M 40-32 and # Y crx, s g. Bn?, may seg. dx v6, also crossed onto Dutton's Flint In- bred (5 and 6), (freezing injury, poor germination); 3 ears " 40-83 and # pwr Y gs , seg. fl?, may seg. v6, also pol- linated with Inbred I (l and 2); 6 ears " 40-84 # Pwr crx , seg. y sk, may seg. dx blx vx , also pol- linated with Inbred I (l) and reciprocally with Dutton's Flint Inbred (5 end 6 ); 2 ears n 40-88 (x) Seg. Pr pr, may seg. yga, also pollinated with Inbred II (3) and Dutton's Flint Inbred (5) and reciprocally with Inbred I (l); 6 ears " 40-89 (x) Y, seg. pr wx, may seg. cL. also pollinated with Inbred I (l); 7 ears " 40-91 x) and # lgx , seg. y, may seg. pgx ; 3 ears^ M 40-92 x) Y wx?, seg. su, may seg. ar , also pollinated with Inbred il (3 ); 4 ears " 40-93 (x) Y wx?, seg. Pr pr su, may seg. ara, also crossed onto Dutton’s Flint Inbred (6); 4 ears "40-94 (x) Seg. Pr pr su wx?, may seg. pga, also pollinated with Inbred II (3). and recipro- cally with Inbred I (2) and In- bred II (3 and 4); 7 ears " 40-95 (x) and # Pwr Y cr, seg. wx pg2 "white stripe", may seg. 1 gx , also pollinated with Inbred I (1 and 2) and reciprocal- ly with Inbred I (l) and Inbred II (3 ); 7 ears " 40-96 (x) A PI, seg. y Pr pr lg gl2 B v4, may seg. tsx ; 3 ears " 40-98 (x) y Hadjinov's gl5, seg. vx , also pollinated with Inbred II (3) and reciprocally . with Inbred I (l); few seeds 433 Co 40-99 (x) y Hadjinov's gl6; few seeds " 40-100 (x) y, may seg. Hadjinov’s g!7; 5 ears " 40-101 (x) 3eg. y B PI fj may seg. wx Hadjinov’s glo, also pollinated with Inbred I (2) and reciprocally with Inbred I (l) and Dutton's Flint Inbred (6); 3 ears " 40-102 (x) P Y Hadjinov’s gllO, also pollinated with Inbred I (l and 2) and Inbred II (3); 4 ears " 40-103 (x) and # "Deep Y" lg gl4, may seg. vx bmx , also pollinated with Inbred I (l and 2), and reciprocally with Dutton’s Flint Inbred (5 and 6); 9 ears " 40-105 (x) and # Y, seg. rs2 glx ; 5 ears " 40-107 (x) and # Seg. y Pr I? Hadjinov’s at si ts2 br? bv?, may seg. f, al30 pollinated with Inbred I (l and 2) and reciprocal- ly with Inbred I (l); 6 ears " 40-108 (x) Pvr Y, may seg. Hadjinov’ 3 b3 vx ; 1 ear " 40-109 (x) and § Y A b PI, seg. P vb, may seg. Vv, also pollinated with Inbred I (1) and reciprocally with Inbred I (l); 6 ears " 40-110 (x) and # y A PI (zg3) lgx , seg. B dx , also pol- linated with Inbred I (1); 7 ears " 40-111 ‘M A. seg. y Pr R&8 su B PI ba, may seg. vx , also pollinated with Inbred I (2); 11 ears " 40-112 (x) and # A suam?, seg. y Pr pr PI ba2 vx f? also pollinated with Inbred II (3) and reciprocally with Inbred I (l); 6 ears " 40-113 (x) and # y a lgx , seg. ts4 gx crx , may seg. vx also pollinated with Inbred I (1); 8 ears D M 40-114 Crossed onto Inbred I (2), may seg. dx s dx M 40-115 (x) Pvr, Seg. y Pr pr Rgg Rn^? su B PI lgxx, may seg. g d7 vx , also crossed onto Inbred I (1) and Dutton’s Flint Inbred (5 ); 15 ears " 40-116 (x) and # y a C r pr wx, may seg. ysx, also pollin- ated with Inbred I (l) and Inbred II (3) and reciprocally with In- bred I (2 ); 6 ears (x) and # Seg. y Bn v5 gl, may seg. ws2; 5 ears (x) and // Seg. Pvr y Pr pr c sh wx ws gl4, elso crossed onto Inbred I (l); 6 ears " 40-119 (x) and # Seg. y Pr pr g?, may seg. li ws2, also crossed onto Inbred I (1); 4 ears " 40-120 (x) a B PI wx?, seg. y as lgx "white stripe", may seg. gs, also pollinated with In- bred I (1 ); 5 ears " 40-121 (x) and # Seg. Pr pr po; 10 ears 434 h- CO 1—' 1—1 1—1 1—i 1 1 o o -3" -=t" Co 40-122 U) Y, may seg. st vx ; 2 earsn 40-123 W P a, may seg. br f bm2 n!2 Vy, also crossed onto Inbred I (2); 2 ears M 40-124 (x) and # Y, seg. Pr pr Pl Rg rt bl?, may seg. dx , also crossed onto Inbred I (1 and 2), Inbred II (3) and Dutton’s Flint Inbred (5 and 6); 5 ears ft 40-125 U) and # p w - bm2/lg-b/y?-pl/ c-wx/g - Rgg/j/pr pk?; few seeds t! 40-126 (x) and # Pvv and p-bm2/lg-b/A-Cr cr + cr/Su and su/y? - pl/c-wx/g - RSg/pr/j; few seeds fl 40-127 (x) Seg. Pwr y Pr vp5, also pollinated with Inbred I (2 ); 8 ears If 40-128 (x) pwr y 02 v5 ra gl; 1 ear If 40-129 (x) pwr a B pl ds? anx , seg. y Bn? Lg3?. also crossed onto Inbred I (2); 2 ears It 40-130 (x) Rg ds? anx, seg. y; few seeds II 40-131 (x) Y, seg. su? bt?, also open pollinated ear some- what like Tp; few seeds It 40-133 (x) y pr, seg. Rs-t? wx? g, may seg. mr; 3 ears II 40-134 I X ) and | P A br f bm2, may seg. ts2; 3 ears II 40-135 ( X ) Seg. y4 yx It Pr pr; 5 ears tl 40-136 (x) Hadjinov’s gl6, seg. y Wh?; 3 ears 1941 Co 41-1 Inbred I (U.S. 204) Pwr Y A b pi, pollinated with Y A b pi nl, seg. R, may seg. dx g zb5 (113); Y gllO, may seg. wx (69); Y a lg2 ra2 ? (21); Y cr na a v5 gl, may seg. lgx (34); Y A b pi su vl4, may seg. sh d3 (l66); P Y A b pi, may seg.d5 y5 (57); Y A b pi, seg. hf, may seg. wx vx Rg? ^75); Y A b pi rs2, may seg. glx vx (12); A b Pl Kn (86); Y A b pl gsx , seg. msll, may seg. lgx ( ar- likefT stripe (103); y A b pl vl8, may seg. 14 (91); y A b pl pg2, seg. d (128); may seg. vp v? (l7l); pr A b Pl bm ys, may seg. v2 (l80); small anthers", may seg. pr su (170); nl2, may seg. br f bm2 glx (116); Y A b pl Rs, may seg. glx (13); Y A b pl crx , may seg. vp4 (174); Y A b pl blx (47); bv?, may seg. g pg (126); pr A b pl v3?, may seg. su (156); Y A B pl Ig pk?, may seg. pgx. bmx "white stripe" (132); Y a na yt, may seg. ts4 (182); Y A b pl ds, seg. anx (l4); 28 ears 41-2 (x) Inbred II (West Branch) Y A b pl, also pollinated with Y A b pl nl, seg. R, may seg. dx g zb5 (113); Y A B pl Ig bmx pk?, may seg. pgx 'white stripe (132); pr A b Pl bm v2, may seg. ys (, loO),;, 4 ears 41-3 y A b pl, may seg g3 lx ; 1 ear 41-7 P sh A B pl, may seg. 16; 1 ear 41-9 y su A b pl "yellow flecked leaves", may seg. v3 Lx> 1 ear 41-10 # Bn? A b pl cr?, may seg. v6 dx ; 1 ear 435 Oo 41-11 (x ) and # y A b pi Hadjinov's gl # 6 ;Y 3 ea11 41-12 A b r p si, seg. rs2, may seg. glx vx , also crossed onto Inbred l(l); 3 ears " 41-13 (x) and # A b pi Rs, seg. y, may seg. glx , c ar lo ss os ed onto Inbred l(l); 2 ea " 41-14 # Y A r sb pi ds anx , also crossed onto Inbred 11 j- / » 7 G 3.1? S " 41-15 (x)"and # A b pi gl4, seg. y Pr pr wx? ws; " 41-16 # p 7 w e a- bm2 rs/lg-b/y-pl/c-wx/g-Rgg/j/pr pk?, a p lo sl olinated with 17, same genotype; 5 ears " 41-17 (x) and # PvV - bm2/lg-b/y-pl/c-wx/g-Rgg/j/pi> px.; 5 ears " 41-19 (x) and , # Y _ A b pi, seg. Pr pr sux h?; 3 " e a4 r1-20 x) and # Y a s C R pr in w " 41-21 # x Y ; 6a el ag r2 s ra2?, also pollinated with Y a w Cx ^ R( 2 p0 r.) , i nand with Inbred I (l), and reciprocall w yith Inbred I (l); ̂ e " 41-22 Y a a C r sR Pr B PI pollinate . d %with Y a lg2 ra^. \ c-L )9 1 ear „ " _ 41 ,-23 (x) and # y su a Dt, may seg. I ( gx 2) ; and 9 ears" 41-24 # y a2 A C R v2, seg. P», may seg. bm; 4 ears " 41-25 # y a2 A C R pr bt bv; 5 ears " 41-26 x) and # y a3 (A B pi?) 0g; x ) 3 an ed a rs may " 41-28 # Seg. Pwr y su Ts6 al? ij?/seg. " 41-29 x g ) l xa ; nd o # e arP swr Y A b pi, may seg. an2 vx glx dx , o ears " 41-30 (x) and I Y vx, seg. ar; " 41-31 ^ 9 ear3 Y w x d a A b p i ar sa, seg. Pr pr; * ‘ 3 a en ad rs" 41-32 # y, seg. Pvv B zl as, may seg a .n d m s# l 7y ; Pr 6, ease rg s" 41-33 . B RSS ms!7 as, may seg. zl, 9 ^ 31? S " 41-34 # Seg. y at si blx tsx f fl?, may seg. bv br zbx ry 1 • ~A Q 31? S " 41-35 Y sh A*b pi au au2 crx , pollinated with Inbred I ( 1m )a ,y seg. vp?; 3 ears (includes 2 very sm ( all ea" 41-36 x) and r s)§ Pr Sx A B pi " 41-37 (x) an R d S 8| l gy x P br m xA ; B 2 p ei a rC s Sx lg bm2, seg. g. m 7a •y seg. j d cr ts2 ; 10 ears " 41-38 u Y a B PI C R Pr, may seg. v'vx >: 4 ears " 41-39 \ pew a b pi, may seg. bax ; 1 ear " 41-40 P A pi, seg. y su B ba, may seg. bax vxY >; 16 ears " 41-41 P Y A PI, seg. Pr su B ba2, may seg. bav 'x 13 m * q 2? S " 41-42 # Y Kl ij, seg. P bd; 2 ears " 41-43 (x) and # A b, seg. y PI ra gl ij bd; 10 ear " s 41-44 (x) and # Y A b pi bk glx ; 2 ears " 41-45 (x) and # Y bk2; 5 e # a r" 41-46 P s Y A b pi, seg . . n s 9k pr>9.lgx , may seg. dx vx bl. cr., " 41-47 Y A b pi blx , crossed onto Inbr # ed" A I U 41-48 B ) PI lgx , seg. y Pr ( sx k) 2 x , an md a y# sy e ga " R4 g1 8- R4 e9 ar A C R b sp i v2, seg. (x P) w ra ; nd 1 5# eY a, i s" 41-51 seg. Pwr sh wx vx , may seg. bp zb?; 17 ears 436 Co 52 # P¥r Y A b pi bt2, may seg. glx "white stripe", 1 0 n 41- 53 (x) and # y c, seg. su, may seg. v9; 3 ears it 41- 54 Y cr na a v5 gl, crossed onto Inbred I (1), may seg. Xg n 41- 55 Y A b pi, pollinated with Inbred I (l), seg. Pwr Tu dH "white stripe", may seg. su; 3 ears ii 41-■56 (x) and # P Y sh wx c, may seg. d3; 4 ears it 41-■57 P Y A b pi,ii crossed onto Inbred I (l), may seg. d5 v5 41--58 (x) and # Y wx?, seg. nl?, may seg. dt ms?; 2 ears^ it 41-■60 Y de A b pi, pollinated with Inbred I (l), seg. mi?; 2 poor seeds it 41-■61 (x) and # y a Dt lg, seg. ts4 na su, may seg. g; 6 ears i i 41-■62 # Pvr Y f12 glx ; 2 ears it 41-■63 (x) and # gl ij, seg. y, may seg. ra fr fr2; 11 ears ti 41-■65 x) and # y A b pi Og li g; 2 ears m 41-■67 (x) and # Y, seg. su, may seg. Ga; 6 ears ii 41-•68 (x) Pvr Y wx gl3 cr2 , seg. su, may seg. wl, also pollinated with inbred I (l); 3 ears ii 41--69 # y gllO, may seg. wx , also crossed onto Inbred I (l); 2 ears it 41-•72 (x) and # y A b pi gl6, seg. P?; 3 ears it 41-■74 (x) and # y A b pi, seg. gl7 vl7 Hadjinov's gl7, may seg. "white stripe"; 4 ears it 41-*75 (x) Pwr Y A b pi, seg. gl9; 1 ear> it 41--76 (x) and # Seg. Pvr y lg v4 gs2, may seg. g!2; 15 ear ii s41--77 pwr Y A b pi h, pollinated with Inbred I (1); few s 0 0 d s it 41--78 (x) and # Pwr Y A b pi, seg. wx hf vx , may seg. Rg?, also crossed onto Inbred I (l); 3 ears ti 41--79 # y A b pi Hs; 2 ears it 41--30 # y A c R^S pr in su, seg. Pvv sh wx, may seg. vx ; 3 ears ii 41--82 (x) and # Seg. y4 and or yx It Pr, may seg. srx ; 6 ears it 41 y4 It I .t -83 . a c r pr I pollinated with Inbred I (1J; 1 ear it 41'-84 (x) and # A b pi, seg. y sh Vc? msS j glx , may seg. vl6; 4 ears it 41 -85 (x) and # Y A b pi gl3, seg. su, may seg. j2; 5 ti ears41 -86 # A, seg. y B PI Kn, also crossed onto Inbred I (1J; 3 ears it 41 -87 (x) P A B pi lgx bk?, may seg. 1 w; 1 ear • it 41 -83 (x) and # r, seg. y su PI "white stripe , may seg. g 12; 8 ears ir 41 -89 # pwr y "white stripe", may seg. 1 3 ; few IT seeds41 -90 (x) and # Pvr Y "white stripe" li?, seg. Pr, may seg. 13; 4 ears II 41 -91 y A b pi vl8, may seg. 14, pollinated with Inbred I (l) 1 and reciprocally with Inbred I (l); few seeds 41 -92 pwr y A b pi, may seg. sh 17 ms2, pollinated with Inbred I (l); 2 ears 437 i1—1 Co 41-93 (x) Y su A B pi Ts5?, may seg. la; 1 ear; also su A B pi la pollinated with (94) su A B pi Ts5 la lgx, may seg. glx ; few seeds " 41-95 (x) Pwr Wc? A b pi glx , seg. y, may seg. msx ; 2 ears " 41-97 (x) and # A b PI, seg. Pwr Pr pr Rst r fl? ^ se8 - g mr "white stripe"; 2 ears " 41-98 Y A b pi, seg. Pvr ms2, may seg. 17 brx , pollinated with Inbred I (l); 2 ears " 41-99 P A b pi, seg. ms5 , may seg. lgx , pollinated with In- bureodu Ix (l); 1 ear " 41-100 (x) a n d # P Y A B pi, seg. Pr pr ms6, may seg. gx ; 4 ears " 41-101 # A b pi, seg. y ms9; 2 ears " 41-102 fj pwr^ seg. mslO "white stripe , also pollinated with Inbred I (l); 3 ears „ _ , . , M 41-103 # Y, seg. P msll gsx , may seg. lgx , ar-like strip., also crossed onto Inbred I (1); 2 ears H " 41-104 (x) Y A b pi, may seg. ms!2 bmx white stripe v.; 1 ear " 41-105 # y, seg. m3l3; 4 ears " 41-106 # Y, seg. wx sh msl4; 4 ears " 41-107 (x) and # Pwr, seg. Pr pr bm, may seg. mslb lx igx dy; 2 ears , " 41-109 (x) and # P b PI, seg. A*3? ms37; 5 ears " 41-111 pwr y a b pi, may seg. vl9 msx, pollinated with in- bred I (l); 2 ears „ " 41-112 # Seg. Pwr y Pr pr su B PI na2, may seg. white stripe"; 2 ears " 41-113 # Y A b pi nl, seg. r Pr, may seg. g zbj dx, also crossed onto Inbred I (l) and Inbred II (2); few seeds " 41-114 # P Pr A b pi g, may seg. nl zb5 glx* also pollin- ated with (113) Y A b pi nl; 2 ears " 41-115 x) and # Pw y A b pi r zb5, may seg nl g; 7 ears " 41-116 x) and # a, seg. P br f bm2 , may seg n!2 glx , also crossed onto Inbred I (l); 5 ears " 41-117 # Y o A B pi, seg. VX ; 5 ears . . , M 41-118 pwr y 02 A b pi, pollinated with Inbred I UJ; I ear " 41-119 # P A b PI sm, seg. py; 1 ear " 41-120 (x) Seg. Pr pr zb? pg? pb?, may seg. msx and usually completely sterile plants with necrotic leaves; 1 ear " 41-122 (x) and # y A b pi pb4, seg. glx J ? ears " 41-123 (x) Y wx, may seg. pbx lgx white stripe ; 1 ear " 41-124 # Pw , seg. y B pbx , also pollinated with Inbred i (l); 2 ears " 41-126 # pvr pr bv?, may seg. g pg, also crossed onto In- bred I (1 ); few seeds " 41-128 # y A b pi, seg. pg2 d, also crossed onto Inbred I (l); 6 ears " 41-129 (x) Pr, seg. su, may seg. pga; 2 ears " 41-130 (x and # y A b pi, seg. lg ; 8 ears " 41-131 (x) and # y lgx , seg. pgx ; 1 1 ears 438 Co 41-132 (x) and # Y lg pk?, seg. B "white stripe" p mg ax y b sm ex g, . also crossed onto Inbred I (l) and Inbred II (2); 4 ears " 41-133 u pwr y a b pi bi „ n, , 1m ta py seg. pgx msld lg s xt ri wp ne i", t ealso pollinated with Inbred I (l); 6 ears " 41-134 # pw, seg. y pm lg2 ; 9 ears " 41-135 # pr A b PI; 4 ears " 41-136 (x) a n d # A b pi R§8 Pr; 5 ears " 41-137 # P A b pi, seg. ra2?; 2 ears " 41-138 and # P, seg. Pr a lg2 ra2 ra ; 9 ears " 41-139 a nd # Seg. y lgx glx dx "light green , may seg. W„'y v4: 12 ears " 41-140 # y 3u2 lgT, seg. Pwr sb ms 3 ?; 5 " 41-141 y e A a rsb pi b pk?, may seg. sh, pollinated with Inbred 1 (l*); 1 ear ^ " 41-142 (x) and # Seg. Pcr Pcw y sb msx ; 6 ears " 41-143 # Y blx, seg. Pr si at br f bv? ts2?, may seg g .l *. v x also pollinated with Inbred I (l); ( 7x ) e a2 rs" 41-145 nd # y A b pi sr bm2, seg. Pw^ Pr an; 10 ears " 41-146 # ? v r o2 A b pi v5 ra gl, seg. y; 6 ears " 41-147 # Y A b pi, may seg. st; 4 ears " 41-143 # suam du A b pi, seg. y; 6 ears " 41-149 # sy A b PI, seg. y, may seg. al; few seeds " 41-150 (x) and # A to pi, seg. Bn? tn Vy dx ; " 41-151 $ y r 5 a gl v5, also pollinated with Inbred I 11-)* 2 ears " 41-152 s v'S el see. Y Pr pr wx? ra Tp; 3 ear " 41-153 (x s ) and'# A,’ seg. y su Pr pr Bn? v5 ra gl Tp B PI; 6 ears " 41-154 # P br f bm2, seg. a, may seg. ts2; 2 ears " 41-155 (x) and # y, seg. Pr Mt? tw3 gx srx glx , may seg. blr, 7 ears " 41-156 # pr A b pi v5?, may seg. su, also crossed onto Inbred I (l); 1 ear . " 41-157 (x) and # A b pi, seg. y Pr pr v3, may seg. vx ; 4 s sir s " 41-153 # P^r Y A b pi v7-striped; 2 ears " 41-159 (x) and # Pwr Y A b pi, seg. v7-striped " 41-160 # y ; v!2 4 e, ars see. pr. may seg. lgx, also pollinated /rith Inbred I U ) r 4 ears " 41-161 (x) and # Seg. y Pr pr PI vl3; H ears " 41-163 # Y su A b pi, may seg. sp lx ; 1 ear " 41-164 x ) and # Seg. P y su, may seg. sp; x 7) ea an rs " 41-166 d # Y su A b pi vl4, seg. sh, may seg. d3, also crossed onto Inbred I (1); 2 x ) e aa rn sd " 41-167 # wx? li, seg. y su PI, may seg. " 41-168 x) w p xw ;r 1y 0 v e2 a0 r sl gx, also pollinated with Inbred 1 (1 j * 4 ears " 41-169 (x) a n d # P y A b pi, seg. va2, also pollinated with Inbred I (l); 6 ears " 41-170 "small anthers", may seg. p T r , su, , crossed onto Inbred " 41-171 (x") y Pr A b pi, seg. r vp, may seg. vx , also cross- ed onto Inbred I Tl); 1 ear (x) pr .Vx pk?, seg. vp2?, may seg. bmx ; 4 ears 439 Co 41-173 x) pr pk?, seg. vp2?, may seg. vx bmx ; 2 ears " 41-174 x) and # pwr Y A b pi crx , seg. vp4?, also crossed onto Inbred I (l); 2 ears " 41-175 pwr y A b pi crx , may seg. sh vp4, pollinated with Inbred I (l); 2 ears „ w " 41-176 (x) and # Pvv y A, seg. wa "white stripe Bw? PI, 3 ears „ " 41-177 # Y Wc A b pi, may seg. "white stripe ; 1 ear " 41-178 # A b pi, seg. y Pr pr Mt? g 11 ws2; 11 ears " 41-179 (x) and # Y Y A B pi, seg. yx , may seg. wx al; A ears „ , " 41-130 # pr bm, seg. y Mt? sh wx ys v2 PI, also crossed onto Inbred I (l) and Inbred II (2); 3 ears " 41-181 (x) and # y a C r pr wx, may seg. ysx ; 3 ears " 41-132 # Y wx a yt, seg. na, may seg. ts4, also pollinated with Inbred I (l) and reciprocally with Inbred I (1 ); 3 ears " 41-133 # Y A b pi zb4; 2 ears " 41-184 'x) Pwr Y A b pi, seg. zb4; 2 ears " 41-135 x) and # Y A b pi, seg. zb4; 4 ears " 41-137 x) and # Y T8-9 homozygous terminal number 9 xnob, seg. B PI also R&6 or rsg; 6 ears " 41-191 (x) and # y Tl-2; 2 ears " 41-192 (x) and# y A pi Tl-2b, seg. Pwr Pr pr B, may seg. vx; 3 ears " 41-194 # a? bm bt pr A A C C R R; 133 seeds " 41-195 (x) a2 bt pr, seg. y bm; 1 ear J. E. Welch Trisomic stocks The program began by Randolph in 1940 of Improving and building up reserve stocks of all the available trisones was continued in the summer of 1941. Trisomes one and four are still missing. Root tip counts were made on over 1500 plants to determine the trisomic plants. Over 300 ears were harvested. In making crosses several inbred stocks were used as well as different genetic tester stocks. These were all checked to make sure that no B chromosomes were present. Selected ears have been turned over to the Coop, and are here listed under Coop, numbers. Co 41-196 No. 2 trisome x Luce’s Favorite Inbred 1 . (x) - 2 ears 2. x L. F. Inbred - 5 ears 3 . x Ig - 2 ears 440 41-197 No. 2 1. (x) - 4 ears 2. x L.F. Inbred - 1 ear 9. # - 9 ears 41-198 No. 2 trisome x Inbred II (West Branch) 1. (x) - 1 ear 2. x L.F. - 3 ears 3 . # - 1 ear 41-199 No. 2 trisome x lg 1. x L.F. - 4 ears 2. # - 2 ears 41-200 No. 3 trisome x lg2 1. (x) - 6 ears 2. x L.F. - 2 ears 3 . # - 3 ears 41-201 No. 3 trisome x L.F. Inbred 1. x L.F. - 2 ears 41-202 No. 3 trisome x Inbred II 1. x L.F. - 3 ears 41-203 No. 5 trisome x Inbred II 1. (x) - 1 ear 2. x L.F. - 5 ears 3 . x bt - 2 ears 41-204 No. 6 trisome x su2 1 . (x) - 3 ears 2. x L.F. - 5 ears 3 . # ~ 2 ears 41-205 No. 7 trisome x L.F. Inbred 1. x L.F. 2 ears (all ears of trisome 7 poor) 41-206 No. 7 trisome x Inbred II 1. x L.F. - 2 ears . 2. x gl - 1 ear 3 . open - 1 ear 41-207 No. 8 trisome x L.F. Inbred 1 . (x) - 2 ears 2. x L.F. - 3 ears 3 . # - 2 ears 41-208 No. 8 trisome x j 1 , (x) - 2 ears 2. # - 2 ears 41-209 No. 9 trisome x wx (No. 9 also vx) 1 . (x) - 2 ears 2. x L.F. - 4 ears 3 . # 1 ear 41-210 No. 1<) trisome x L.F. Inbred 1 . (x) - 1 ear 2. x L.F. - 4 ears 3 . x vlS - 2 ears 41-211 No. 1() trisome x vl8 1 . (x) - 2 ears 2. x L.F. - 2 ears John Einset 441 V. Index of Seed Stocks Propagated in 1940 and 1941 A complete index of all Cobp stocks on hand at the close of the 1959 season appeared in the 1940 News Letter. The cul- ture number of an inbred is followed by the number in parenthe sis of the male parent carrying the gene in question, m.s. - may segregate. a Co 40~1 (71), 40-2 (71), 40-2 (ll6 ), 40-2 (i23) , -40-26, 40-70, 40-71, 40-72. 40-75, 40-113, 40-116. 40-120, 40- 125, 41-1 (2 1 ), 4l-l (5^), 41-1 (18 2), 41-20, 41- 2 1 , 41-22, 41-25, 41-58, 4l-6l, 41-85, 41-116, 41-158, 41-154, 41-181, 41-182 a.P 40- 18, 40-45 Ab? 41- 109 a2 41-24, 41-25, 41-49, 41-194, 41-195 a3 4!-26 al 41-149 (m.s.), 41-179 (m.s.) al? 41-28 an 41-145 an2 41-29 (m.s.) . , 0. anx " 40-2 (3l, m.s.), 40-2 (129, m.s.), 40-25, 40-31, 40-129, 40-150, 41-1 (14), 41-14 ’'anthers small" Co 41-1 (170) ar Co 41-50, 41-51 , . , , . ara 40-6 (95, m.s.). 40-92 (m.s.), 40-95 (m.s.) as 40-120, 41-52, 41-55 at 40- 1 (107), 40-107, 41-54, 41-145 au 41- 55 au2 B 40-M101, m.s.), 40-1 (69), 40-1 (115, m s.), 40-2 (129), 40-5 (69), 40-5 (115, m.s.), 40-5 (69), 4o-o (1 0 1, m.s.), 40-17, 40-13, 40-45, 40-51, ^0-o9, 40-75, 40-76, 40-96, 40-101, 40-110, 40-111, 40-115, 40- 120, 40-129. 41-7, 41-22, 41-52, 41-35, 41-36, 41- 37, 41-38, 4l-4o, 4l-4l, 41-43, 41-86, 41-37, 41-93, 41-100, 41-112, 41-117, 41-124, 41-132, 41-153, 41-179, 41-187, 41-192 Bw? n 41-176 ba it 40-111, 41-40 ba2 it 40-1 (1 1 2 ), 40-112 bay it 41-39 (m.s.), 4l-4< bd it 41-42, 41-43 bk m 41-44 bk2 it 41-45 bk? ti 41-37 tr blx 40- 5 (84. m.s.). 4 41- 1 (47), 41-34, bl? it 40-1 (124, m.s.), 40-2 (124, m.s. 40-3 (124, m.s.) 40-5 (124, m.s.), 40-124, 41-46 (m.s.) bm it 40-62. 41-1 (180), (m.s.), 41-107, 41 442 bm2 Co 40-2 ( 1 2 3 , m . s . ) , 40 -21 , 4 0 -4 5 , 40-123 ( m . s . ) ,4 0 - 125, 40 -126 , 40 -134 . 41-1 (116 , m . s . } , 4 1 - lo , 4 1 - 17, 4 1 -3 7 , 41 -116 , 41-145 , 41-154 iinv -5r-4) i 411 or\ -5c. bm3 7 t / bmx 40-1 ’(69), 40-3 (69), 40-5 (103, m.s.), 40-6 103, m s ) 40-5 (69), 40-69, 40-103 (m.s.), 4l-l (lo2, 41-2 (13 2b 41-36, 41-104 (m s.), 41-132 (m.s.), 41-172 (m.s.), 41-173 (m.s.) Bn Bn? J o-MSl, m.s.), 40-2 (129, m.s.), 40-5 (92, m.s.), 40- 6 (82! m.s.); 40-31, 40-32, 40-129, 41-10, 41- 150, 41-153 bp br 40-l1(l07,*m.s.), 40-2 (123), 40-21, 40-45, 40-123 (m.s.), 40-134, 41-1 (1 1 6, m.s.), 41-34 (m.s.), I41n-1 1 6,. 41-1435,. 41-154 brx 41-98 (m.s.) br? " 40-107 bs Hadjinov Co 40-108 (m.s.) bs? Co 40- 67 (m.s.), 41-120 (m.s.) bt n 41- 25, 41-194, 41-195 bt2 41-52 bt? 40-■1i3p1i , . , x bv 40-•1l ' (107, m.s.), 41-25, 41-34 (m.s.) bv? 40-• 107 '* 41-1 (126), 41-126, 41-143 40-• 1 1(113, m.s.), 40-113, 40-125, 40-126, 4l-l6, 41-•17, 41-53, 41-56, 41-30, 41-33 cr 40-•*1 (95), 40- -3- (-9-5-)-, 40-95, 40-126, 41-1 (54), .̂ 7 7m a \ crx 40-2 (81, m.s.), 40-5 (92), 40-6 (32), 4°-5 (84, m.s.), 40-6 (34, m.s.), 40-76, 40-73, 40-81 (m.s ), 40- 82, 40-84, 40-113, 41-1 (174), 41-35, 41-68, 41- 174, 41-175 cr ? 41-10, 41-46 (mm .so .)1 , d 40-2 (114, m.s.), 40-2 (129), 40-25, 40-26, 4400-48, 40- 129 (?), 40-130 (?), 41-1 (12 8), 41-1 (14), 41- 14, 41-37 (m.s.), 41-123 d3 40- 75 (m.s.), 41-1 (l66, m.s,), 41-56 (m.s.), 41- 166 (m.s.) d5 41-1 (57, m.s.) % d7 40-1 (115, m.s.), 40-5 (115, m.s.), 40-115 (m.s.) da 40-89 (m.s.N db (m. s. % dv 124, m.s.), 40-2 (124, m.s,), 40-1 (74, mi . s. 31, m.s.). 40-2 (114 m.s.), 40-3 (124, mm ss. 124, m.s.), 40-6 (124, m.s.}. 40-5 (74, m.s. 82, m.s.), 40-6 (82, m.s.}, 40-5 (34, m.s.), 84, m.s.), 40-74 (m.s.), 40-77 (m.s.). 40-78 40-79 (m.s.), 40-80 (m.s.), 40-81, 40-32 m.s.), 40-84 (m.s.), 40-110, 40-124 (m.s ),4l-l 1 1 3 , m.s.), 41-2 (113, m.s.), 41-9 (m.s.), 41-10 im.s.), 41-29 (m.s.), 41-46 (m.s.), 41-107 (m.s.), 41-113 (m.s.), 41-139, 41-150 443 de Co 41-60 Dt " 41-25, 41-61 du f " 40-f (101, m.s.), 40-1 (107, m s.) 40-1 (71), *0-2 (71 \ iin-2 (123), 40-6 101), 40-21, 40-45, 40-71, 40- 72, 40-101, 40-107 (m.s.), 40-123 (m.s.), 40-154, 41- 1 (1 1 6, m.s.), 41-34, 41-116, 41-143, 41-1^4 " fx 40-1 (74), 40-5 (74), 40-74 (m.s.), 40-79 f? " 40-1 (112, m.s.), 40-112 fl " 40-24, 40-47 f 12 41-62 fix 40-73, 40- 30 fl? 40- 83,41- 34, 41-97 fr 41- 63m . s. fr2 41-63 m. s. fs 40-20, 40-44 g 40-1 (115, m.s.), 40-1 (119, m.s ..1 m.s. ), 40- 5 (115, m.s.), 40-30 (m.s.), 40-65, 40-jo,40-115 (m.s.), 40-125, 40-126, 40-133, 126 m s ),41- 1 ( , m.s.), 41-2 (113, m . s . ) , 41 16, 41 17, 41-61 (m.s.), 41-65, 41-33 (m.s.), 41-97 41-113 (m.s.), 41-114, 41-115 (m.s.), 41-12. (m.s.), 41-173 , . 40-60 (m.s.), 41-3 (m.s.) gg4? 40-52, 40-55, 40-53, 40-59 6x 40-113, 41-100 (m.s.), 41-155 g? 40-119, 41-37 Ga gl 40-63/ 46-1 1 7 , 40-123, 41-1 (54), 41-42, 41-43, 41.-63, 41-146, 41-151, 41-152, 41-153 g!2 40- 22, 40-23, 40-24, 40-46, 40-47, 40-96, 41-7- (m.s.) gl3 41- 68, 41-35 , c gl4 40-1 (113), 40-5 (103), 40-6 (103), 40-27, 40-23, 40- 29, 40-49, 40-50, 40-103,40-113, 41-15 gl6 41- 72 gvr 41-74 gl9 41-75 g i i o 41-1 (69), 41-69 gl5 Hadjinov Co 40-1 (93), 40-93 gl6 Hadjinov " 40-99, 40-136, 41-11 gl7 Hadjinov 40-100 (m.s.)‘ , 41-74 % , glS Hadjinov 40-1 (101, m.s ), 40-6 (101, m.s.), 40-101 (m.s.) gllO Hadjonov 40-102 gl Cx o 40-105, 41-1 (12, m.s.). 41-1 (116, m.s.), 41-1(13, m.s.), 41-12 (m.s.), 4l-lp (m.s.), 41 2o (m.s.), 41-29 (m.s.), 41-34 (m.s.), 41-44, 41-52 (m.s.). 41-62, 41-34. 41-93 (m.s.), 41-95, 41-116 (m.s.5, 41-122, 41-139, 41-143 (m.s.), 41-155 40- 120 (m.s.) gs2 41- 76 gsx 41-1 (103), 41-103 gs? 40- 83 h 41- 77 444 h? Co! 41-19 hf 41-1 (73), 41-78 I Hs I 41-79 , , I? 40- 1 (107, m.s.), 40-10I 7 ij 41- 42, 41-43, 41-63 M i3? 41-23 in I 40-70, 41-20, 41-80 It I Un-i^R in -82 41-83I 3 40- 11 (m.s.),’40-36 (m.s.), 40-70, 40-125, 40-126,41- 16, 41-17, 41-37 (m.s.), 41-34 It 32 41-85 (m.s.) Kn II 41-1 (36), 41-86 Knob II 41-137 II 1 41-87 (m.s.) 12 It 40- 66 (m.s.}, 41-83 m.s. It 13 41- 8 9 (m.s.), 41-90 (m.s. j 14 It 41-1 (91, m.s.), 41-91 (m.s.) 16 II 40- 76 (m.s.), 41-7 (m.s.) II 17 41- 92 (m.s.), 41-98 (m.s.) N II 40-1 (64, m.s.) i ,x 40-5 (64. ms.), 40-60 (m.s.),40- 62 (m.s.), 40-64 (m.s.), 40-68 (m.s.), +1 j (m.s.), 41-107 (m.s.), 41-163 (m.s.) la 41-9 3 - ■ lg 40-1 ( 6 9 ) 40—4^, ' ̂ j 'w ' - , . ~ 40-125, 40-126. 41-1 (132), , - . . hi-~zir7 4i-6l 41-76, 4l-132 lg2 1*0-25’ 40-26’ 40-48, 41-1 (21), 41-21, 41-22, 41-23 (m.s.), 41-134, 41-133 Lg3 40-2 (129) Lg3? 40-129 Igx 40-1 (95, m.s.), 40-1 (115, m.s.), 40-1 (112, m.s.;, (7 1 ), 40-2 (71), 40-1 (64, m.s.), 40-3 (95, ) i ™ q \ 40-^ (64. m.s. ). 40-0 11 11? ml? 41-60 , . mr 40- 133 (m.s.), 41-97 (m.s.) ms2 41.92 (m.s.), 41-98 ms5 41- 99 ms6 41-100 ms8 41-84 ms9 41-101 mslO 41-102 ms 11 40- 31 (m.s.), 40-51 (m.s.), 41-1 (103), 41-103 ms!2 41- 104 (m.s.) ms!3 445 t msl4 Co 41-106 msl7 " 41-32 (m.s.), 41-33 mslS " 40-62, 41-107 (m.ss..)), 41-133 (im.s.)j ms 37 " 41-109 msx ” 40-1 (74, mm,.s.), 40-5 (74, m.s.), 40-67, 40-68 (m. s. ), 40>--7r, 4.,, 41-95 (m.s.), 4.1-111 (m.s.), 11 120 (m.s.), 41-142 ms? " 41-53 (m.s.), 41-140 Mt? 41-155. 41-173, 41-130 na 4i-l (54), 41-1 (132), 41-61, 41-182 na2 4in1 -n1 1i 2o nl 40-30 (m.s.), 41.-1 (113), 41-2 (113), 41-113, 41- 114, 41-115 (m.s.) nl2 40-2 (123, m.s.), 40-123 (m.s.), 4l-l (ll6), 41-116 (( m .as . )i nl? 41-53 o 40-17, 40-42, 41-117 o2 40- 128, 41-118, 41-146 Og 41- 26, 41-65 pwr 40-1 34 (84 40- 40- 40-_., . - .. , 40-31, 40-41, 4U-40, 4U-D4, 40-54, 40-55, 40-57, 40-62, 40-74, 40-31, 40-33, 40-34, 40-95, 40- 103, 40-115, 40-113, 40-127, 40-123, 40- 129, 41-1, 41.-24, 41-23, 41-29, 41-49, 41-51, 41- 62, 41-63, 41-75, 41-76, 41-77, H w i ; 41-39; 4i1-90;, 414-912-'9,2 ,4 411--9955,, 4411--9977,, 41-93, 41- 102, 41-10■ 7, 414-11-11.1 , 414-11-121.2 , 414-11-151,5 ,41-llS, 41-124, 41-126, 41-133, 41-134, 41-140, 41-145, 41-146, 41-153, 41-159, 41-163, 41-174, 41-1^5, 41-134, 41-192 p C W 41-39, 41-142 per 41-142 p V V ^0-15, 40-39, 40-125, 40-126, 4l-l6, 41-17, 41-32 P J o - f u S ^ s . ) , 40-1 (71), 40-2 (71), ^0-2 (123), 40-4 (65, m.s.), 40-8. 40-13, 40-33, 40-43, 40 51, 40- 65, 40-71, 40-72, 4o-76, 40-109, 40-1 4 21 3- , 1 (57), 41-7, 41-40, 41-41, 41-42, 41-46, 41-56. 41-37, 41-99, 41-100, 4l-103, 41-109, 4 4 11 -114, -1 1 6, 41-119, 41-137, 41-133, 41-154, 4l-lo4, 41-159 P? 41-72 pb4 41-122 P^x 41-123 (m.s.), 41-124 pb? 40-67 (m.s.), 41-120 40-4 (6 . Pg 5, , m.s.) r, 40-65, 41-1 (126, m.s.), 41-126 Pg2 40-7(95, m.s.), 40-3 (95, m.s.), 40-95, 41-1 (123) Pg 4a 0-2 (94, m.s.), 40-3 (94, m.s.), 40-4 (94, m.s.), 40-94 (m.s.), 41-129 (m.s.) 446 Co P 4S 0x -62 (m.s.), 40-91 (m.s.), 41-1 (132, 41-2(13 2, m.s,), 41-131, 41-132 (m.s.), 41-133 (m.s.) pg? " 40-67 (m.s.), 41-120 pk 40-1 (64), 40-5 64 , 40-64 pk? 40- 1 74), 40-5 (74), 40-74, 40-125, 41-1 (132), 41- 2 (132), 4l-l6, 41-17, 41-132, 4l-l4l, 41-172, PI (1 1 2 , m.s.), 109), 40-3 m.s. ), 40-6’(124; m.s.L 40-6 (1 0 1, m.s ),40-18, 4400--2222, 40-31, 40-43, 40-51, 40-73, 40-96, 40-101, 40-109, 40- 110, 40-111, 40-112, 40-115, 40-120, 40-124, 41- 1 (86), 41-1 (180), 41-2 (130), 41-22, 41-33, 41-41, 41-43, 41-43, 41-36, 41-33, 41-97, 41 -109, 41-112, 4 1-1 1 9, 41-135, 41-149, 41-153, 4l-lol, 41- 167, 41-176. 41-130, 41-187 pm 40-25 (m.s.5, 40-48 (m.s.), 41-134 po 40-67, 40-121 . , ,, . , pr 40-1 (83, m.s.), 40-1 (1 1 8, m.s.), 40-1 (6 1), 40-1 (L1 5 , m.s.), 40-1 (1 1 2 , m.s.), 40-1 (124, m.s.), 40-2 (124, m.s.), 40-1 (119, ms.), 40-2 (94 ms.), 40-2 (1165, 40-3 (124, m.s.), 40-3 (94, m.s.), 40 4 (94, m.s.), 40-5 (115, m.s.), 40-5 (124, :L: f •} ’ 40-6 (124, m.s.), 40-6 (93, m.s.), 40-66 (m.s.), 40-67, 40-70, 40-33, 40-89, 40- 4 90 3,- 94, 40-96, 40-112, 40-1 1 5 , 40-116, 40-118, 40- 1 1 9, 4o -121, 40-124, 40-125, 40-126, 40-133, 4°-lj5, 41- 1 (130), 41-1 (170, m.s.), 41-1 (156), 41-2 (130) 41-15 41-16, 41-17, 4l-19, 41-20, 41-25, 41-31, 4l-3o’ 41-83, 41-97, 41-100, 41-107, 41-112, 41-120, 41-135, 41-152, 41-153, 41-156, 41-157, 4l-lo0, 41-161, 41-172, 41-173, 41-178, 41-180, 4l-l8l, 41-192, 41-194, 41-195 p y 41-119 RrS 40-1S 40-59 Rgg 40-1 (69), 40-1 (115, m.s.), 40-5 (69), 40-5 (H5, m.s.), 40-5 (69), 40-59, 40- 115, 40-125, 40-126, 4l-l6, 41-17, 41-55, 41-56, 41- 57, 41-43 (m.s.), 41-30, 41-156, 4l-155, 41-187 ( ? ) rrr 40- 40 rgg 41- 107 (?) 40- 2 (1 1 6 ), 40-66, 40-116, 41-85, 41-83, 41-97, 41- 115, 41-115, 41-171, 41-131 Rn j 40-15 RnJ? 40-1 (115, m.s.), 40-5 (115, m.s.), 40-115 Rmb 40-11, 40-56 Rst .40-12, 40-57, ^0-68, 41-97 Rst? 40-54, 40-155 , . , , . ra 40- 55, 40-56, 40-128, 41-45, 41-65 (m.s.), 41-146 41- 151, 41-152, 41-155 ra2 41-158 ra2? -1 (2 1 ), 41-21, 41-22, 41-157 447 rax C11o 41-133Rg 40-2 .129), 40-it Rg? 41-1 ( '78, m.s. Rs ti rs2 11 41-1 (.13), 4i-: 40-105, 4i-i (: rt IT 40-1 (124), 40' 40-124 1 sx 40-1 (69), 40-: 41-37 sa II 41-31 sb It 41-140, 41-141 sh II 40-1 1(ll8, m.s 40-5 1(64), 40-' 40-75., 40-76, 41-35 , 41-51, 41-106, 41-141 si It 40-1 (107, m.s sk II 40-5 84), 40- 41-46 skx II 40-1 (74), 40- si 1 40-53 slx It 40-63 sm 1 41-119 sp It 40-9 (m.s.), 4 41-164 (m.s. ) sr It 41-145 srx II 41-32 (m.s.), st It 40-122 (m.s.), .-147 m.s.) , , su II 40-1 (6l, m.s. 40-1 (115, m.s.), 40-1 (71, m.s.), 40-2 (71, m.s. 40-2 (94, m.s.), 40-3 (94, m.s.), 40-4 (94, m.s. 40-5 (115, m.s.), 40-6 (93, m.s.), 40-71, 40-72, 40-75, 40-73, 40-79, ^°'80, 40-92 4 .0- 93, 40-94, 40-111, 40-115, 40-126, 41-1 (166), 41- 1 (170, m.s.), 41-1 (156, m.s.), 41-9, 41-23, 41-28, 41-40, 4l-4l, 41-53, 41-55 (m.s.), 41-61, 41-67, 41-68, 41-80, 41-35, 41-38, 41-93, 41-112, 41-129, 41-153, 41-156 (m.s.), 41-163, 41-164, 41- 166, 41-1 it 67suam 41-148 suam? t 40-1 (112), 40-112 su2 it 41-140 siix it n 41-19su? it 40-131sy 41-149 T - Translocations Co 41-137, 41-191, 41-192 tn Co 41-150 Tp t 41-152, 41- Tpx ti 40-131 Trisome 2 Co 41-196, 41-197, 41-198, 41-199 Trisome 3 " 41-200, 41-201, 41-202 Trisome 5 " 41-203 Trisome 6 " 41-204 Trisome 7 " 41-205, 41-206 Trisome 8 " 41-207, 41-208 Trisome 9 " 41-209 448 0 1 \J1 O' Trisome 10 Co 41-210, 41-211 ts Co 40_pp 40-73 ts2 40-1 |107,, m.. as.. );, t4u0-107, 40-134 (m.s.), 41-37 (m,..3. )),. 41-154 (m.ss.. )) ts2? ts4 40- 26 (m.s.), 40-113, 41-1 (182, m.s.), 4l-6l, 41- 182 (m.3.) Ts5 41-93 Ts5? 41-93 Ts6 41-28 t s x 40-96 (m.s.), 41-34 Tsx 40- 77 Tu 41- 55 tw5 v2 t x - i i i ™- , , 441l-_d2 I(Jl. OSoUiI , t41i -24, 41-49, 41-180 v5 40-1 (6 1), 406-611,, 41-1 (11556)) (?), 41-156 (?). 41-157 v4 40-22, 40-24, 40-47, 40--7733,, 4400--9966, 4l-7o, 41-139 v5 40-117, 40-123, 41-1 (54), 41-1 (57, m.s.), 41-146, v6 (32 m s.) ^0-6 (32 m s.), 40-31 (m.s.), 40-82 (m.s.), 40-83 (m.s.), 41-10 v7 11 40- 16, 40-41, 41-15ti 8, 41-159 v8 1*0-77 (m.s R .), 40-78 (m.s.), 40-(9 (m.s.), 4 j 80 (m.s.), 41-9 (m.s•) it v9 41-i 55 (m.s.)vl2 41-160 it vl5 vl4 it 40- 751 (m.s.), 41-1 (166), 41-166 vl6 ii 41- 84 (m.s.) it vl7 41-74 vl8 it 40- 19, 41-1 (91), 41-91 v itl9 41- 111 (m.s.) v20 ii ii • --- .), 40-1 (115, m.s.), 40-6 (34, m.s.), 40-5 (64, m.s.). 40-3 tm.s.1, 40-17, 40-27, 40-29, 40-33 (m.s.), 40 4 -0 4- 2 , 6 44 0 -5( 0m ,.s.), 40-69 (m.s.), 40-78, 40-30, 40-3 (m.s.), 40-98, 40-103 (m.s.), 40-108 m (i ms! .) s: . ).4 4 0 4- 011 11 (m.s.), 0-112 40-113 (ms.), 40-, (m.s.), 40-122 (m.s.), 4l-l (78, m.s.), 4l-l (12 m ,. s.), 41-12 (m.s.), 41-29 (m.s.), 41-34 (m.s 4 .1 )- , 38 (m.s.), 41-40 (m.s.), 4l-4l (m.s. ( )m , s 4l) -44 o1-51. 41-78, 41-30 (m.s.), 41-117, 4^ 14, (mis.), 41-150, 41-157 (m.s.), 41-171 (m.s.), 41-172, 41-175 (m.s.), 41-192 (m.s.) V? 41-1 (171, m.s.), 41-57, 41-104 (m.s.) va2 41-169 vb 40- 1 (109), 40-109 vp 41- 1 (171, m.s.), 41-171 vp2 ? 41-172, 41-173 449 vp4 Co 41-1 (174, m.s.), 41-175 (m.s.) vp4? " 41-174 vp5 " 40-127 vp? " 41-55 (m.s.) w " 41-B7 (m.s.) Vx " 40-2 (1 2 3.'m.s.), 40-75 (m.s.), 40-125 (m.s. K 41-1 (69, m.s.), 41-69 (m.s.), 41-159 (m.s.), 4l-lo, (m.s.), 41-179 (m.s.) wa " 41-176 Wc " 41-177 Wc? " 41-84, 41-95 Wh " 40-65 ¥h? » iin-40 40-136 "■white stripe" Co 40-1 (95), 40-5 (95), 40-51 (m.s.), 40-51 (m.s.), 40-95, 40-120, 41-1 (105, m.s ), 41-1 (152, m.s.), 41-2 (152, m.s.), 41-52 (m.s.), 41-55, 41-74 (m.s.), 41-33, 41-89, 41-90, 41-97 (m.s.), 41-102, 41-105 (m.s.), 41-104 (m.s.), 41-112 (m.s.), 41-125 (m.s.), 41-152, 41-155 (m.s.), 41-176, 41-177 (m.s.) wl Co 41-68 (m.s.) ws " 40-1 (llB, m.s.), 40-113, 41-15 ws2 " 40-117 (m.s.), 40-119 (m.s.), 41-173 ws2? " 40-1 (119) ws3 wx wx? 40-1 (98), 40-1 (113, m.s.), 40-1 (10 1, m.s.), 40-, (107, m.s.), 40-1 (69). 40-1 (115, m.s.), 40-1 (11, m.s. 5, 40-1 (119, m.s. , 40-1 (64, m.s.), 40-2 (ll6 40-2 (8 1, m.s.), 40-2 (129, m.s.), 40-5 (69), 40-5 (115, m.s.), 40-5 (69), 40-5 1 34, m.1 s.). -6 40-6 (-4,_ _ \ iin_c f w, o iin nni . m-a.). 40-9, 40-62, 40-64, 40-bo, 4U-00, -tv- 1 40-75, 40-79, 4o-8l, 40-84, 40-91, 40-96, 40-9- 40-99, 40-100, 40-101, 40-107, 40-110, 40-111, 40-112, 40-113, 40-115, 40-116, 40-117, 40-118, 450 rn ifi-48, 41-49. 41-55, 4l-6l, 41-65, 41-65, ^l~69, 41-72 41-74! 41-76, 41-79: 41-80, 41-84, 41-86, 41-88, 41-91, 41-95, 41-101, 41-105, 41-112, 41-115, 41-118, 41-122, 41-124, 41-128, 41-130, 41-131, 41-133, 41-134, 41-139, 41-140, 4l-l4l, 41-142, 41-145, 41-146, 41-148, 41-149, 41-151, 41-152, 41-153, 41-155, 41-157, 4l-l6o, 41-101, 41-164, 41-167, 41-169, 41-171, 41-176, 41-178, 41-180, 41-181, 41-191, 41-192, 41-195 n 40-135, 41-82 (m.s.), 4l-83 40-46, 40-135, 41-82 (m.3.), 41-179 yg2 40-28 40-49 yga 40- 1 '(88, m.s. ), 40-7 (m.s.), 40-32 (m.s.), 40-88 (m.s. ) „ ys 41- 1 (180), 41-2 (l80, m.s.), 41-180 ysx 40- 2 1 1 6 . m.s.), 40-116 (m.s.), 4l-lSl (m.s.) yt 41- 1 (182), 41-182 , zb4 40-10, 40-21, 40-55, 40-45, 41-185, 41-184, 41-185 zb5 40- 50, 41-1 (115, m.s.), 41-2 (115, m.s.), 41-115 (m.s.), 41-114 (m.s.), 41-115 zbY 41- 54 (m.s.) zb? 40-67 (m.s.). 41-51 (m.s.), 41-120 zg5 40- 110 (m.s.) zl 41- 52, 41-55 (m.s.) J. E. Welch 451 MAIZE GENETICS COOPERATION NEWS LETTER 17 1943 The data presented here are not to be used in publications without the consent of the authors. Department of Plant Breeding Cornell University Ithaca, N. Y. 452 M A I Z E G E N E T I C S C O O P E R A T I O N D e p a r t m e n t o f P l a n t B r e e d i n g C O R N E L L U N I V E R S I T Y I THACA, NE W Y O R K December 10, 1942 To Maize Genetics Cooperators: Thix is the annual call for copy for the next News letter. I have set January 31, 1943, as the dead­ line date for this material. Please send copy to the Department of Plant Breeding, Cornell University, where it will be assembled and forwarded to me at Pasadena, California, Since the emergency has doubtless mada i^ imposei.J.­ for some of you to continue your genetic studies, those who have material suitable for the News Letter should make an effort to get it to me on time. Sincerely, f 2 ^ u 7 r L e ^ x ka 1 :P R. A. .’Emerson 453 CONTENTS Page I Reports from coc/perators ....................... 2 Bureau of Plant Industry Station ........... 2 California Institute of Technology ......... Columbia University......... *.............. Connecticut Agricultural Experiment Station.. Cornell University ......................... Duke University ............................ Georgia University............... ......... Harvard University ......................... Missouri Botanical Garden .................. IT Missouri University ............ 19 U.S.D.A. and Cornell University ............ Venezuela Instituto Experimental de Agrieultura y Zootecnia ................. ^7 II Maize Publications ....... 32 III Inventory of seed stocks propagated in 191­2.... 454 I. REPORTS FROM COOPERATORS The data presented here are not to be used in publications without the consent of the authors* R. A. Emerson Bureau of Plant Industry Station, Beltsville, Md. Several backcross progenies involving genes located on chro 3 mosomes and 7 were grown in 1941* They were not reported in the last News Letter as the data had not been summarized, hence they are reported now. A few additional backcross progenies were grown during the past season and are reported* Cold, wet weather following planting resulted in veiy poor stands in both seasons, but it is felt that the segregations obtained are not sufficiently distorted to modify gene order. 1. Backcrosses involving genes on chromosome 7* gl ij bd7 + + + 0 1 2 1-2 Total 69 53 4 4 68 26 4 2 122 8 94 6 230 Linear order and map dis tances are: gl ­ 6 .1 ­ ij ­ 43.5 ­ bd7 (500 seeds were planted , 46.0% produced mature plants.) gl a! ij + ♦ + 0 1 2 1-2 Total 268 182 32 52 2 5 0 2 450 34 7 2 543 Linear order and map distances are: gl ­ 15.3 ­ si ­ 1.7 ­ ij (1,000 seeds planted, 54.3% produced mature plants.) 02 ra gl ij + + + + 0 1 2 3 1 - 2 1­3 2-3 1­2­3 Tbtal 273 213 24 28 6 3 49 56 1 1 5 7 0 4 86 2 1 0 52 9 105 2 12 2 1 669 Linear order and map distances are: 02 ­ 10.0 ­ ra ­ 2.1 ­ gl ­ 1 1, 70 *0 90 ­ij( seeds planted, 66.9% produced mature plants.) 455 02 ij M7 + + + 1 2 1­2 Total 69 56 24 44­ 38 44 125 7 17 68 82 24 299 Linear order and rnap distances are: 02 ­ 30. ( 85 00 ­ ij ­ 35­3 ­ W 7 seeds were planted, 5 9 M produced mature plants.) 2. Backcross involving lg2 and genes on Chromosome 3* rt + lg2 a + Bg + + 1 2 3 1­2 1­3 2­3 1­2­3 7 6 36 33 23 35 4 2 4 3 15 11 135 13 74 63 6 7 26 1 325 order and map distances are: rt ­ 8.3 ­ Rg ­ 32.9 ­ lg2 Merle T. Jenkins California Institute of Technology, Pasadena, California Much (btaiied information has been collected on the nume l ro oc ua st i to rn as n su ­nder study. I do not feel that this informatio e nn o wu og uh l dg en De e ra ol f interest to be reported in raw form in the N S eo wm se Lt ei tm te e rI . hope to get it organised in more useful form f .e w Hm ei rs ec e al rl ea n ae ous items, and a brief statement on the practical use of translocations. 1. A plant homozygous for Tl­2c but heterozygous ior str p ie ar ti ec a ar np d color (repulsion) backcrossed gave +P28, +£49, s sh ro w Pi 4n 3g , l §i Ln k £a 2g 5e with about 37 per cent crossing over. Sin v ce er y T lc ­l 2o cs e ist o sr, this places it to the left of sr, subst i an nd ti ic aa tt ii no gn s t hf er om previous data submitted by Emerson and by myself. 2. A crossover has been obtained between Y1 and i6­9 h be ,l p w ht io c hd e mt a}e 'r mine the position of Y1 on the chromosome. Y 1 h Ta hs e pb oe sen i tm ia od ne Oxd ifficult by the great amount of suppressi o ov ne r o fw h ci rc oh s sh ia ns g ­c haracterized all translocations thus far studied p r io nx i tm ha el half of the long arm of chromosome o. 3. A number of new translocations have been isolated i n af no dr m sa ot mi eo n collected. They include the following which have been 456 rH O identified as to chromosomes involved Index index number Chromosomes number Chromosomes a-33 1-3 F­2 2­10 c-43 1-3 a- 10 1 3­5 g-3 1-3 a-22 3­8 c-15 1-3 a­94 3­ 9 a -37 1-5 a­2.6 4­ 9 a~80 1-6 c-31 4­9 B-49 1-7 F­22 4­ 9 D-5 1 - 7 B­45 4-10 B­42 1­8 B­10 5- 8 C-36 1­10 B­70 5-10 a -29 2­ 4 a-66 6­ 9 c­7+0 2-8 F­33 8­10 4. One complex translocation (Index No. B—2) involves four chromosomes 1, 3> 4> and $. It is closely linked to su. It is al^o c lose to bm with much suppression of crossing­over between cm and jar. No linkage "information has been obtained on chromosomes 1 and 3. 5. Utilization of translocations with endosperm markers in the study of economic traits. In studying the inheritance of any diffic t ur la tit , a simple test can bo made for linkage with an endosperm character such as su or wx, especially if the multiple recessive combination occurs in one of the commercial inbred lines. For example, in studyin r ge sistance to bacterial wilt, a resistant line can oo crossed with s u as ceptible sugary, and the Fp crossed to a susceptible sugary inbre C do .m parison can then be made between the resistance of plants from starchy vs. sugary seeds of the backcross car. This tests for resistance gene i sn the central portion of chromosome 4. If this test is negative th a ensimilar test can be made involving translocation 1­4&. (Resistant x su Tl­4a) x susceptible sugary inbred, a test of plants from fiu v s se .e ds su then becomes a test for resistance genes in the long ar,of chromoso F mer om 1 . the standpoint of testing technique, it means that su can be used a am sa rker for any chromosome or part of a chromosome for which the proper t ranslocation is available. And the same recessive sugary inbred lin c ea n be used for all backcrosscs. The suppression of crossing­over in the neighborhood of the translocation aids in making the method mere e fficient in detecting linkages* Ii* an appropriate series of translo e cx ai ts it oe nd s, it would be possible to cover the entire chromosome complement with the use of one endosperm gene such as su. The series of translocations available at present is not sufiicient to cover all chromosomes usin0 only one marxor gene. By using two serie o sn ,e with su, the other with WX* it is possible to nave­ at least on t e­r anslocation for each chromosome. More translocations are being isolated a nd it is hoped that, year by year, the scries available for this purpose will be greatly improved and simplified. 457 Work on the inheritance of economic traits by m ua sr ik ne gd et nr da on ss pl eo rc ma tions is being taken up at several e xp oe fr i tm he en t c os rt na t bi eo ln ts . To facilitate these p c rr oo gs rs aes m s he I ro h aa vt e P ma as da e de tn ha e Jw ii th such translocations as are now available These were: su series ­­ l­4a, 2--A&, 2-U c, 4-5b, 4­5d, 4~6a, 1 ­8, 1­9a, l­10b and a new 2-1 (a­29) For sweet corn lines I was able to add 1­7a, a new 1­9 (j.h­22), 1­10 (B­15) and a multiple 1­3­1­5 (B­2) wx serios ­ l-9 a , l -9 c , 2-9b, 3­9a, 3­9b, 3-9 9 c,1 0 4-9b, <>-9u,­ 8­b 9 aa ,nd new 1­9 (F­22), and 6­9 (a­66) 2T series ­ l-5 a , l-5 o , 2-5b, 3-5b, 3-5c, 4 -5 c , and 4­5d The above is too large a serios for completion of s tu ec sh t st ,r a ei xt cs e pa ts fc oa rn easily be tested in the se a ed dd li it ni go n sa tl a gF eL . ‘s Bm ua ty ts he er ve as a reserve for checking any indication. o linkage# 6. Use of translocations in corn breeding. f Oo nr c ea n a ne yc o sn io gm ni ic f it cr aa ni tt gi es n e located, it should bo poss r iu ble e t to o a tn ry a nc so fm em re r tc hi aa tl inbred line with only t h a mi in nb ir me uS m l oi fn e a li tt es re al tf i. o n I on simplest form, the inbr c er do s ls ie nd e w wi ot uh l dt h fe i rp sr to p be e­r translocation (one near the T lh oe c uF s'i ow fo u .l hd e t gh ee nn t )b *e ba ­c kcrossod recurrentl S yw a ty os tht eh e ins be rm ei ds te lir ni tl o sp el la en ct ts i. n g Then on selling, the h t oi mo on z yi gn ob ur se d tc ra an n sb le o cai ­solated. The next step consis t tr sa n os fl o cc ra ot si so in n gi n tb hr ee d with the desired gene, and back t cr ra ons sl so mc ga t ti oo n . hi en bred. Then, on solfing an th de er le is mu il nt a tis nh gou l td h e be essentially the inbred line h ge on me o. z ygoTh ue o l fe on r gt th h e of a .t si im re e d required is considerable, b y b uv ta r ci ao nu s b es h ro er ­dt uc ou .,t s. No great number of plants m u nc eh e dl a bb eo r g rr oe wq nu ,i r ne od r. isA nd an economic gene could n u om eb e tr r ao nf s fi en rb rr ee dd .l oi n ae ns y simultaneously. This s mu ec th h ot dr a ii st s s ua gs g ea sr te e dd i of rf a.i cu x lt to follow, such as for d i es xe aa ms pe l, e i rn es se ic st ts a, n cd er o tu ot h or cold. It is essenti w ah li lc yh ac no n it nr do il rs e ct th e m ev ta hl ou able but difficult character by p ol sl ube sn t is te um ti is ot ne r oi fl ity which can be easily and precisely fol­owo . E. G. Anderson Columbia University, New York City i. Relation between knobs and ehroinoccn R te ers st i on fg in nu tc ..l .e i a.o f maiz aue c ls ct ia .i ned with Feulgen con s tt aa ii nn i dn ig s cb ro ed ti ee ,s di en e pa ld yd ition to diffuse chromati s ct a mi an ti en rg i ab lo .d ie Ts h ea sr e­o dc ea el pl le yd ­ chromocenters. A goo b de ^t cw oe re rn e lt ah te i on nu m wb ae sr fo of u n chromocenters in the interkinetic nuclei and the 458 number of knobs present in the pachytene chromosomes. In strains free from conspicuous knobs but possessing B chromosomes a good correlation was found between the number of B chromosomes and the number of chromocenters. The chromocenters derived from B chromosomes are not as large as those from some of the larger knobs — evidently all of the heteropycnotic material observed in the B chromosomes at pachytene is not represented in the chromoconter. That portion of the B chromosome immediately adjacent to the centromere of the B is more knob­like in appearance tnan otner portions of the chromosome and it is believed that it is this proximal portion which forms the chromocenter. Plants free from conspicuous knobs end B chromosomes have a great majority of their interkinetic nuclei free from any structures which might be interpreted as chromocenters (except for the two nucleolar organizer regions on chromosome 6). That chromo­ centers' often fuse is indicated by the range in number and size. Strains vith knobs of approximately uniform size have chromoccnters of uniform size — barring fusion — while strains with different sized knobs have a marked range in size of chromocenters. The data obtained are summarized in the following table. Knob No. Number Mean No, Range Tissue at B chrom nuclei chromo­ in Modal studied Strain pachytene No. counted centers number class root A 9 0 100 8.16 4 -11 8 style A 9 0 100 8.00 4­12 8 root B 6 0 100 5­05 2­8 5 root C 6 0 100 5.22 2­6 5 root D 0 U 100 3.27 1­5 4 root E 0 0 100 0.22 0­1 0' Occasionally the number of bodies classified as chromocenters was greater than the number of conspicuous knobs. This may be due to the misclassification of diffuse heterochromatin as chromocenters or more likely to the failure to distinguish small knobs at pachytene. Fusion of two or more of these small knobs might give rise to recognizable chromoccnters. In every strain stu led. the number of chromocenters was determined before that of knob number. All preparations were stained with the Feulgen reaction. D. T. Morgan, Jr. 2. The interaction of bronze (bz) with factors determining anuhocyanin colors. ­ The bronze (bz) gene modifies the pigments involved in plant color. A B PI bz plants are not purple but aro a deep reddish­brown. A B p]L bz plants have a bronze instead of a sun red color ­ the bronze color is also a sun color. A _b PI bz and A b̂ pi bp plants are pigmentea but the normal red pigment of the culm and glumes is transformed into a bronrush pigment. The bronze gene is not concerned with the primary reactions detex’­ mining the presence or absence of color but does modify in some way the pigment molecule. Aleurone color is also affected by bronze ­ the effect being a ’bronzing1 of the purple (Pr) and red (pr) pigments. Pericarp 459 color is not affected i.e. plants of A P bz constitution have red pericarp. The action of bz on both the plant and aleurone colors may indicate a close chemical relationship of these pigments. The following linkage data on the location of bz have been obtained: Percent Number of recombination individuals Yg2­3z self 13 2656 Bz­C B.C. 5 573 Bz­C self 5 313$ Bz­Sh self 8 454 Bz­Sh self 10 739 Bz­Wx self 24 454 Bz­Wx self 30 739 Bz­V self 33 739 On the basis of the above data, which are mostly F2, the bz gene falls between yg2 and C. Inasmuch as Dt is 7 units beyond y&2 the revised linkage map of chromosome 9 is tentatively as followr. Dt Yg2 Bz C Sh_______Bp M _____V 0 7 21 26 29 44 59 71 3. Gametophyte factor in chromosome 3. A gamete factor having a a nd verse effect upon the ability of pollen grains possessing it to eifee f te rtilization has been located in chromosome 3. This new gamete factor is independent of the genetic constitution of the silks and hence is d ifferent in this respect from the gamete factors in chromosomes 4 an P do l 5l ­e n with this factor is not visibly different from normal. Approxi m a , tcly 12 .7% of the functioning pollen from heterozygous plant;, carry t he gamete factor. The linear order in chromosome 3 is L£2 A_£a with g ta hm ee te locus some 10­12 units from A. Presumably it should lie close to etched (ejt). A. The preference of Jap beetles for liguleless­1 leaves. ihe sev i en rf ee station of Japanese beetles in the summer of 1942 at Irvington, ma ..d . e ■ p . ossible the observation chat these beetles found the leaf ­issue of liguleless­1 (lgl) plants very much to their liking. Leaves of t ae lls te ir £ strains were nearly destroyed and many plants died. In axi culture s se gregating for lgl an accurate classification for lg. ano Lg could oe made from tho amount of leaf tissue eaten by the insects. Lg. plan^b adjacent to sister lg. plants were nearly free from beetles while l tg n e plants literally swarmed v/ith them. Plants homozygous tor Igp. had t s ha em e, or nearly so at any rate, degree of infestation as did their normal sibs. M. M. Rhoades 460 Connecticut Agricultural Experiment Station New Haven, Connecticut 1 . A late flowering mutation arising in one of the long inbred Teaming strains, C14, shows no appreciable differences in plant or 4ed size at full maturity. At two weeks after planting the late plants ore about half as tall as the normal inbred plants. These slower­ 'rowing plants are about six days later in silking but continue rapid Growth longer and finally arrive at approximately the same height at the end of the season. This is an example of a deleterious recessive, not easily detected, that slows physiological activity. 2. Reciprocal crosses between inbred strains may show small differ­ pnees in amount of growth in early stages after germination due to differences in embryo size or seed condition. These differences usual y^ disappear by the time the plants flower. In crosses of a Rice pop inbreci . with very small seeds and a yellow dent inbred with largo seeds marked differences were obtained in the reciprocals. Three weeks after planting the dent parent was nearly twice as tall as the pop parent and proportiona y larger in overall size dimensions. At this stage the dent x pop is taller than the dent parent while the pop x dent Fp occupies an inter­ mediate position between the two parents. The hybrids and parents tassel and silk in the same order as their initial embryo weights: V.L) dent x pop, (2) dent parent, (3) pop x dent, (4) pop parent. At the end of the season the two reciprocal crosses arc equal in production of gram and in height and both are tailor and more productive than either parent. Production of grain of the hybrid is about 15 times that of the pop parent and nearly twice as much as the dent. Both reciprocals reach ful maturity at about the same time but the one that is smaller at the start continues rapid grov/th longer to reach eventually the same height and production of grain in approximately the same length of time, o in ce one of the hybrids starts smaller after germination and ends up larger m the amount of material produced than the larger parent, in the same period of growth, one ij) growing at a faster rate than the ouhei . The parents and reciprocal crosses also differ in the number of tillers. The dent inbred averages .03, dent x pop 2.06, pop x dent 1.24, and pop inbred 2.83 tillers per plant. The larger number of tillers is shown by the hybrid with the non­tillering seed parent.^ In these reciprocal crosses having the same genic constitution, tillering is an expression of initial vigor large enough to overcome any differences in maternal effect. Differences that may exist in the cytoplasm of these two widely diverse reciprocal crosses have no effect on the final reaction product between the external environment and the nuclear construction of the hybrids. D. F. Jones Cornell University, Ithaca, N. Y. 1. Aberrant pericarp­color ratios. ­ A few years ago I reported a recessive zygotic lethal, zl, with its locus near P in chromosome 1 of maize (Gonetics 24: 368­384. 1939). The effect of zl is to prevent, 461 i+jj rare exceptions, homozygosis of genes with which it is closely United, and thereby to change a 3:1 to a 2:1 Fo ratio when zl is linked with a dominant gene or to prevent the occurrence of one class when linked with a recessive gene. When a plant heterozygous for zl is crossed with one lacking zl, there is, of course, no disturbance of ratios in the resulting progeny. The locus of zl, relative to other chromosome­1 genes i sr msl7 ­ ts2 ­ P ­ zl br 1.7 1.3 1.5 Another case of disturbed pericarp­color ratios has occurred in at least three supposedly unrelated lines, all of which, however, are found to have had one individual plant as a common ancestor a lew generations back, namely, a chromosome- 1 marker with the genotype p br an gs. This suggests that the disturbance is associated with P rather than with its recessive allele. Two selfed red­eared plants gave progenies totaling 33 red to 89 white, while three other selfed reds gave progenies with normal 3:1 ratios. The former also gave aberrant and the latter normal ratios when used as the pollen parent in crosses with white­eared plants. Fourteen cultures, resulting from white pollinated by heterozygous red, have had a total of 329 plants with red and 1143 with non­red ears. Some of these crosses huve involved also Tl­3a, the totals being 404 T ana 120 non­T. Two cultures involved ms17, P, and T1­3&, from the cross: ms + + ' + P + . This 3­point test gave ty he following results:m: + T 0 1 2 1,2 Total 18 152 0 6 10 18 0 2 170 6 23 2 206 2 M 13.656 l.C# The percent of recombination is: ms ­ P = 3.9, P ­ T = 14*6. The recombination value for P ­ T is less than that indicated by Anderson^ (News Letter 14 p.2. 1940). The striking thing, however, is the ratios of dominant to recessive markers, as follows: +• : ras = 28 : 178 P : + = 36 : 170 + : T = 42 : 164 From these aberrant ratios it may be inferred that the locus of the disturbing element is to the. left of msl?. hliether the disturbing iactor is transmitted through the egg is not known. It is transmitted through the pollen. Only a part of the red ears of a culture that shows the aberrant ratio yield such ratios in the following generation. The nature of the responsible gene, if gene it is, is not known. It is certain, however, that it is not a recessive zygotic lethal and not a 462 complete pollen lethal. So far as now known, it might be a pollen semi­ lethal or a gamete factor, but if the latter, it differs in some respects fr om the Ga gene that disturbs the ratios of the starchy­sugary pair and 0thcr characters of chromosome 2. White­capped red pericarp. ­ In last year's News Letter I p resented data which I interpreted as showing that white­capped red pericarp of such varieties of maize as Bloody Butcher is not allelic to ordinary red pericarp, JP, as had been supposed, but is conditioned by multiple genes at least one of which is linked with red cob color and therefore with P. I presented data from F£> F3, and backcross t eh se c or fo ss of colorless pericarp and white cob, W­W, with Y/hite­cappe p de ricarp and red cob, C­R. From this cross, the four possible combinations of pericarp and cob colors were obtained, namely, C­R, C­W, W­R, VM . Grades of pericarp color from 0, no color, to 6, the color intensi o tf y the Bloody Butcher parent, were reported and the behavior in inheritance was shown to be that typical of quantitative characters. This year I present data from further F3 cultures and also fr p o m cultures. For brevity in the accompanying table, I have grouped together cultures which have about the same ranges of variation, and may, therefore, in so doing, have combined genetically heterogeneous material. Certain conclusions may be drawn from these data: (l) ­ From the cross W­W x C­R, there have appeared in F3 or F^ in relatively true bree f do ir nm g, the four possible combinations of pericarp and cob colors, namel W y­W , (item 1), W­R (item 2), C­W (items 21, 28), and C­R (items 20, 25, 3 0 2, 9 ,3 3). (2) ­ There have appeared types that breed relatively true p e fr oi rcarp color while still segregating for cob color: W­R and W­W (item C ­R 3 )a ,nd C­W (items 22, 26, 27). (3) ­ Some cultures still show mark v ea driation in intensity of pericarp color while breeding true for red cob ( si tems 11, 17) or white cobs (items 10, 16). (4) ­ In all culture h sa v te h aa tny pericarp color and that are segregating for cob color, t,he e w ai rt sh red cobs have a higher mean grade of pericarp color than do those with white cobs. (5) — In a few cases, the ears with ­hite cob^ h p ae vr ei c na or p color while some or all of those with red cobs have more or p le er si sc arp color (items 5, 6, 7, 18). (6) The gene or genes conditioni p ne gr icarp color in these instances (5 and 6 above) may be assumed to be i n chromosome 1 near the locus of IP. (7) ­ Selection is effective in establishing lines with diverse intensities of pericarp color. From the trisomic cultures of Mr. Einset has come the suggestion that one or more genes affecting white­capped red pericarp color may be in chromosome 5« In a culture segregating for trisome 5 and for thi t sy pe of pericarp color, the ears of trisomic plants had unmistakably m in ot re en se pericarp color than did those of disomic ones. This behav t io o rb e i se xpected of characters that show a gene­dosage effect as white—cap p pe er di carp color does. A beginning has been made in the use of the ot t hr ei rs omes in an attempt at a further genetic analysis of this pericarp color. 3* Differential dominance in number of kernel rows. ­ In the 194­0 News Letter (14: 19­21), I reported differences in relative dominanc t ee 1 n 2 ofi nbred lines of —row maize and of two 8­row inbred linos in crosses 463 F^ and cultures of the cross W­W x C­R lumber Grade Progenies Item of of Cob Mean Mn f ultures parent color 0 3 1 5 6 otal: grade 1 3 0 W 131 131 : 0 o 2 0 R 116 — - 116 : 0 — - 3 2 0 fR 73 73 : 0 23 __ — - 25 : 0 A 1 0 R 51 4­ ­ _ _ - 55 : 0*1 1 0 fR 32 6 __ - _ - 33 : 0.25 (W 15 — __ — - 15 : 0 / R 2 10 _ __ — 0.86 1 1 - 12 : 7 W 6 — — 6 : 0 1 1 (R 13 19 6 1 — _ - 39 : 0.9 7 (W 8 , — _ 8 : 0 8 1 2 w 6 8 16 12 — — 12 : 1 .8 1 2 / R 9 5 12 10 _ — - 36 : 1 .6 9 lw 4 2 2 3 — - - 1 1 : 1 . 1 10 8 3 w 56 36 16 66 17 — - 221 : 1 .8 1 1 1 3 R 2 1 2 3 13 5 - 26 : 3.58 1 7 23 10 - - 19 : 2.5 12 2 3 9 2 3 6 2 _ - 22 : 1.5 13 3 3 w H 17 29 8 — _ 68 : 2.5 U 1 3 R 6 16 13 1 1 — - 16 : 2.6 15 1 3 R 6 5 — - 1 1 : 3.5 16 1 1 W H 3 8 1 1 19 5 - 60 : 2.6 17 2 1 R 13 20 12 25 12 3 - 85 : 2 .1 Cr 6 1 101 1 - - 2 1 : 2.5 18 1 {w 10 .. — — 10 : 0 19 2 1 R 6 9 19 29 9 67 : 3.6 20 1 1 R - 3 21 12 1 37 : 3.3 21 1 1 W - 7 76 70 2 . 155 : 3.1 / 10 10 69 : 1 . 0 22 2 R 19 1 l w 13 6 - 23 : 3.1 CR' 16 17 21 75 : 3.2 23 o 5 ( W 8 2 — 23 : 1.8 21 1 5 R 9 16 8 13 : 3.5 25 1 5 R 3 7 6 18 : 3.9 fR 10 12 9 32 1 : 3.9 26 5 (W 6 — — 9 : 2.7 1 CR 1 8 16 25 : 1 .6 27 5 tw — 1 2 6 : 1 .3 28 1 5 w 3 12 5 20 : 1 .1 29 3 5 R 12 31 73 126 : 1 .6 30 2 5 R _ 25 55 81 : 1.7 (r 26 U 15 31 : 1 .6 31 1 6 — - 9 : 2 .6 32 1 6 R 3 9 31 1 59 : 1 .9 33 2 6 R 12 12 3 87 : 5.2 464 0f 12­row with 8­row lines. I now present further data on the crosses previously reported and tests of a few inbred lines not represented in the earlier report. The accompanying table includes the earlier as well as the later data. Number of individuals and mean row number of Fp crosses of 8­row with 12­row inbreds 8­ 1 r2 ow lines­row lines 1 51 Snf. W Y. Fir. Y. Fit. R. Fit. * VI 60­ 8.9 54­ 9.7 IV 178­ 9.1 72­ 9.6 III 75­ 9.0 164­10 .1 VII 120­ 9.2 91­10 .1 194­ 9.3 2 346­ 8.9 391­10.5 103­8.8 79­3.8 114­ 9.5 62­9­9 II 89­ 9.7 129­10 .1 4 258­ 9.4 177­10.6 39 625­ 9.6 716­11.4 213­ 9.7 G 93­ 9.1 37­10.1 137­8.6 217­ 9.4 B 221­ 9 .1 284­10.5 144­9.0 151­ 9.7 81­9.5 b 80­ 9.­3 58­10.4 78­9.2 87­9.4 c 91­10.5 88­1 1 . 1 76­9.6 81­10.3 Averages of comparable means 9.4 10.4 9.5 10.5 9.0 9.4 10.5 9.1 : 9.4 10 .6 : 9.7 9.0 10.5 Key to line designations: 1. Luce's Favorite (wiggans) VII Early Pride 2. Onondaga White (Wiggans) R. Fit. Red Flint 4. Bloody Butcher (Wiggans) Snf W. Sanford White 39. Golden Bantam (Purdue) Y. Fir. Yellow Flour 51. Golden Bantam (Purdue) Y. Fit. Yellow Flint II. Westbranch bS Segregates from crosses III. Queen's Golden G l of 8­row with 16­row IV. White Pop lines VI. Dutton's Flint b Of the 8­row inbreds, Sanford White and Yellow Flour are somewhat more nearly dominant even than Luce’s Favorite, while Yellow Flint and Red Flint are less nearly recessive than Golden Bantam. Similar differences are shown by different 12­row lines. Such differences are well illustrated by the following frequency distributions for numoer 465 Ooif kernel *ro­w­s in crosses of two 12­row with two 8­row lines Cross 3 10 12 14 Total Mean 1 with 2 199 144 3 346 3.9 1 " 39 151 437 37 625 9.6 51 " 2 61 183 145 2 391 10.5 51 » 39 13 196 497 10 716 11.4 That these differences in boihavior are conditioned by gene differences rather than by cytopl.asmic diversity is indicated by the fact that reciprocal crosses are essentially alike. The following data from reciprocal crosses are all that are now aval .La Die: Cross 3 10 12 14 Total Mean 2 x 1 69 58 2 129 9­0 1 x 2 79 55 1 135 8.3 39 x 1 65 227 19 311 9­7 1 x 39 70 187 10 267 9.6 39 x 51 9 135 371 5 520 11.4 51 x 39 3 32 67 3 105 11.3 It is not surprising that 12­row lines exhibit differences in relative dominance, because several of them at least are known to have different row­number genotypes. But 8­row types have been assumed to have the same genotype for number of kernel rows. Negative evidence in support of this notion is: (1) Crosses of 8"r h oa ,fv e inn oo *t ? dr sesulted, in my experience, in the product 8 ion of other than ­row types. (2) Crosses of 8­row with 12­row inbreds have not resul i tn e dt ypes with more than 12 kernel rows. It is, of course, conceivable t hat genes responsible for the 8­row condition may be alleles with s am te h e effect on row number but with somewhat different dominance behavior, 4. Genetic diversity of 12­row lines. ­ Data indicating geneti h ce terogeneity of certain 12­row inbred lines of maize have long been a vailable, but have not been reported heretofore in this 'unpublished publication". A brief summary of some of these data follow. Numerous 12­row lines have been obtained from various sources. Some (A, B, G, b, c) from crosses of 8­row flints with 16­row dents and others (III, IV, VI, VII) oy selection from varieties of dent, flint, and popcorn. No 12­row type produces only 12­row ears. There are always some 10­row and 14­row ear 1 s6 and occasionally an­ r 8o ­w r oe wa r. o raT o determine whether a 12­row line is homozygous it is necessary to grow progenies from selfed ears of the more extreme variants. To get such selfed ears it is necessary to hand­pollina e m any plants. This has been accomplished for the 12­row types involv i en this account. A single example of the results obtainea is given ­re \ Line b had in F9 a distribution ranging from 8 to 16 rows with 466 frequencies of 4­18­49­14­1 . In F10 > progenies from selfed ears of diverse row numbers were produced as follows: parent row Progeny number 8 10 12 Ik 16 Total Mean B 1 19 7 1 28 12 .6 10 5 22 9 36 12 .2 12 2 3 27 6 2 40 12 .2 14 4 25 3 2 34 12 .2 16 4 4 34 9 1 52 12.0 The other lines gave similar results. It was concluded, therefore, that all were approximately homozygous. When any two 1 2 of ̂ the nine ­row lines wore crossed, except only b x c, it was easily possi e bs lt ea b tl oi sh lines of different row number. For example, the cross _ b x IV exhibited row­number ranges from 10 to 16 in F^and 8 to 18 in Fy with these frequencies, respectively, 1­43­8­1 and 2­12­37­21­7­2. In F3 the following frequency distributions wore observed: Parent row Progeny number 8 10 12 14 16 1C Total Mean 8 34 12 2 48 8.7 10 2 1 33 7 2 45 12.3 14 6 16 14 1 37 14.5 Given different genes for row number in the several 12­row types, it should bo possible, by multiple crossing followed by selection, to assemble the row­number genes of the several 12­row lines into a single line of high row number. In the accompanying table arc shown the ̂ frequency distributions of all of the ears produced by seven inbrea lines daring several generations when selected for twelve rows. and similar data from certain single, double, and multiple crosses of these lines when selected for high row number. The seven inbred lines had frequency distributions ranging mostly from 8 to 16 rows with strong modes at 12 rows ana means very noai 12 . During the five to eight generations shown in the table and among^ the total of more than six thousand ears, not a single ear had more than 16 rows. After repeated intormittant crossing followed by selfing with selection for high row number, lines have finally been established with modes at 24 rows and means near 23. Two of those lines have not produced an ear with so few as 16 rows. 467 frequency distributions of number of kernel rows of inbred lines and their single, double, and multiple crosses 468 I am now ready to admit that number of kernel rows in maize is a much more complex quantitative character than I assumed iu to be when I began a study of its inheritance. R. A. Emerson Duke University, Durham, North Carolina Controlling starchy contaminations in sweet corn by the use of The gene Ga converged on Purdue 51 gives inbreds whose hybrids ( sixty three sixty­fourths" Golden Cross Bantam) are resistant to pollen contaminations by field corn. In testing it was not found practica e to duplicate field conditions since the inclusion of unadulterated Golden Cross Bantam as a check, diluted the proportion of available Ga pollen. Where this dilution was greatest, with four chuck rows to^one row with Ga, Ga reduced contaminations by 71.6±20.4% (6.E.). /'kere the proportion of Ga pollen v/as higher, the reduction was 76.Gcll.dg. ’When the proportion v/as still higher (approaching l i e l d conditions) the reduction was 82.0­tl2.3fo. Since the differences between these values are not significant, one can only guess that if Ga were introduced into both parents of the hybrid thus doubling the proportion of Ga pollen, Ga might under field conditions reduce contaminations by as much as 90%. H. S. Perry The University of Georgia, Athens, Georgia Translocation 3­5d. ­ T 3­5d v/as isolated in an early dent corn from northern Wisconsin in 1938. (Shuman, JohnR., A chromosomal inter­ change ir maize giving both chain and ring configurations ana low sterility. Summaries of Doctoral Dissertations, University oi Wisconsin Press 57­58. 194.0.) The strain was not subjected to any treatments known to induce cliromosoraal changes. Interchange configurations at aiakinesis were examined in 239 microsporocytes from a heterozygous plant, and 225 were classified as follows: 90.6% of the cells had chains of four chromosomes; 4.4% naa four chromosomes in an open ring, 3.2% had closed rings of four chromosomes and 1.8% had 10 ''bivalents". These observations were interpreted as evidence of a reciprocal translocation in Vihich a comparatively short segment had been exchanged *Tith a longer non­ homologous one. At Anaphase I, 79 microsporocytes from a heterozygous plant had an alternate disjunction of the chromosomes of the complex, a.nd 9/ showed an adjacent separation. These frequencies do not differ significantly from equality. 469 Diakinesis figures from hybrids combining the interchange under investigation with T l-2 a , T 2­9b, T 4~9a, T 6-8 had two independent complexes of four chromosomes and six bivalents; with T 3­8a and rj­i ^_7a there was one complex of six chromosomes and seven bivalents; end with T 3­5b there was one complex of four chromosomes and eight bivalents. Hence chromosomes 3 and $ were involved in the interchange; and it was labeled d since three T 3­5's wore previously described. Three plants heterozygous for T 3­5d had 24.4$ 227/+ pollen grains aborted, and 26.3$ of 1315 possible kernels missing^from the corresponding ears. These two percentages do not differ significantly from each other, nor from the assumed 25$ abortion. Normal plants as the seed parent crossed with T 3­5d heterozygous resulted in /+7 .2$ of 182 plants from two families with 25$ pollen abortion. This per cent of partially sterile plants does not differ ̂ significantly from 50$, i.e. a 1 (normal) : 1 (25$ sterile) plant ratio. T 3­5d heterozygous as the seed parent crossed with normal plant 3 s7 gave .k$ of 251 plants from two families with 25$ abortion. T 3­5d heterozygous plants sibed produced 37.7$ of 212 plants from two families with 25$ abortion. Neither of the latter two distributions differ significantly from each other or from 33 l/3$> i.e. a 2 ("normal'1) : 1 (25$ sterile) plant ratio. It was therefore postulated that of the four equally frequent classes of spores expected in the heterozygoto, only that class deficient for the longer interchanged segment is aborted. The class of spores deficient for the shorter segment but duplicate for the longer one survived through the seed ­ but not through the pollen parent ­ despite the fact that 75$ of the pollen grains appeared normal. Normal plants, those heterozygous and homozygous for the interchange were morphologi­ cally indistinguishable. Plants homozygous for tho translocation wore completely fertile. Johr R. Shuman Missouri Botanical Garden 1. Maize from Michoacan. ­ Professor Ralph Beals of the University of California in making a detailed ethnographic study of two neighboring Tarascan villages in Michoacan, Mexico, collected varieties of maize which ./ere loan d me for study. There were 55 ears in all, from each of which I grev/ ten or more plants at the Blandy Experimental Farm during 1942. The ears were photographed, herbarium specimens were made of the leaves and tassels, measurements and notes were made on the living plants, and these data in condensed tabular form will eventually appear as an appendix to Professor Beals' monograph. As a whole, the maize belongs to the race which Cutler and I have recently termed "Mexican Pyramidal". The ears taper sharply and regularly, most of them show more or less denting, and there is a s trong but variable tendency to irregular rows. The plants are coarse 470 hut the leaves break readily in the wind. They are ve n rt y suT sh ce e pt ta is bs le el s t oh ave few branches or non s eu b­ ar ta o ae ls l' .a ro A tg r lo' ew an s ti n t ht rh ee es e two neighboring villages. For t q wfc o t oh fe re was enough material to define the central co v ra er i oa tion/ BLACK MAIZE is grown only b t eo low 850 0t he homes. gaC rh da er na ct ce _r oi ^stically it has large smoothiy-dente w di t kh e rb nl eu le s or purple aleurone, on a tapering ear abo T uU tL U 1K 5E cN mI .O lv oa nr ^i .eties are grown only above 8500 fe S et m i sn m at lh le rm eou ln at ta ei dn s. In size the ears vary from as l Ma ai rz ge e t ao s v Be lr ay c ks mall nubbins. Their kernel s sh ap v0 ary greatly in sb iu zt e t ae nn dd to be small, more or less pointed, and sli W gh hil te l ya df ee nw t edh .a ve colorless seedcoats, most of a tht et ma i arn ee d l iw gi ht th l yr e sd or reddish brown. None of the I mn hs au vc eh dt aec rh *n i ac la el ur ot na es .sel characters as glume length, tassel b a rn ad n cp he r nc ue mn bt ea g ,e of condensed internodes, the Tulukenio c vl ao rs ier e tit eo s P ^i rm a­Papago maize than to Mexican Pyrami v da ar li .a nts T heo f eT xu tl ru ek mee nio are small­cobbed, non­tapering, ear f ll yi nt sy e, a su on ned de ,n ted, and many tillered. They may po p sr si im bi lt yi v re e fs lm ea cl tl ­ ac obbe _d race something like the maize of Ba ts hk ee t p rM ea hk ie sr ts o. r icT aken in conjunction with Mangelsdorf r ae nc de n Ct aa mn ea rl oy ns i ~ s of knob number in Guatemalan maize, t b he et we de in f feth re e nT cu el su kenio and the Black Maize varieti v ei sl l fa rg oe m d te hm eo ^n ss at mr ea te the importance of considering altitud l ee v ae ol o' vi en si en . terpreting the history and development of Zea ma^s. Of the three Tulukenio varieties which were examined c 1 ytolt ow go icha ad i xyT B , chromosomes and the total knob nu T mh be e rt sw o weB rl ea ck 4> Ma Ui , ze a n varieties which we examined had no a 'n Bd ' h ca hd r ot mo ot sa ol m ek sn ob numbers of 5 and 6. Most of the knob c so mp wa er re ed st mo a it h , ose in the maize from western Mexico (Jalisco), 2 . Glume bar and its inheritance. ­ Many s co eu nt th rw ae ls t Ae mr en r iv ca ar ni e at ni de s of maize are characterized by a i bn at re n os re sc po ol to r o t at the base of the plume in the tas r sa er le . in I tm o id se r rn a td ne ^n rt corn; of eighty inbreds examined at w e Br ee l tw si vt ih lo lu et , a 0n 9y indication of it and in only d fe ov ue rl o wp ae sd . i t I sn t rc oe nr gt la yi n lines and under certain cond s ih ta ir op nl sy . it I st egi rs e ga ap tp ea sr ently independent of both the B an i dt s h e sx ep rr ie es ss i to hn o ui gs x affected by them. It is easiest t ca os s se cl o rh ea s w hj eu ns t the em erged. I have used the following grades m scoring it. readily apparent without handling the tassel ..... + r + eadily apparent only upon handling the tassel ... + of slight and variable expression ............... ± altogether lacking.... ................*......... The only data I have on its inheritance are deri o vf edi nb fr re od ms a fr so em r ieo sn e strain of Papago Flour corn. In t l wo ot co af s us se e td h ew as s amg er own in different places and diffe s re ec no tn d y eg ae rn se .r at Oi no en inbred was scored as all ++ at Cold L o. pI r. i: n g,i n H a1 r9 b4 o1 r ,a nd likewise at Boyce, Virginia in 1 h 9a 4n 2d .” th Oe n fi thr es t otg he en re ration inbred P­3 segregated sharpl i yn i1 n9 1 4 0 M0 i, s sour+ i+ to 26 0. At Cold Spring Harbor in 1941 the second 471 planting gave'a higher percentage of plants with glun,e tor but^in m n y these it was not strongly marked (4­3> + > 5 ° ,f ±,t he a ni ­Jn b 1r 'e >d s ' glume ba vr segregated independently from ( ts hi en e Be at nh de RB and R allelomorphs in this material d ai rf ef er ae pn pt a^ rf er no tm l yt hose in most genetic stocks, no attempt has been made to define them precisely). P­2, leaf sheath slightly sun red, anthers pink, g F li 2 ur 9 ms et ts ae rl l +i .ng, plants all sun red but in v a r y i n g degree, a c no tl ho er r and glume bar segregating as follows: pink anthe anthers, ’ 0 p, 11; green anthers,+, U; green anthers C, 1. P­6, leaf sheath green, bright pink anthers, glume bar First ^clfinr, 27 plants segregating sharply for glume f s of aro U ao nw ds : p red sheath, '++5; green sheath, +*, 13; red sheath, 0, 3, green sheath, 0, 6. P­8. parental type unscored. First selfing, 66 pla s ntr to sn g al ly l sun red, silks green, segregating for glume b c ao rl or a, n d r ae nd anthers,+, 37; green anther,+ , 15; red anther„, 0, 7, ­­ anthers, 0, 7. Michoacan, Mexico. Black Maize Tulukenio Total number of ears 25 26 Row number (from collected ears) U U Glume length in mm. 13 12 Tassel branch number 5 7 Percentage of condensed internodes in tassel 10 20 Percentage of sub­sessile upper spikelets 50 70 Pubescence of sheath scattered heavy Tillers on ten plants 0 0-1 Edgar Anderson University of MSSOU i, Columbia, Missouri 1 Some Alleles of R. Detailed phenotypic comparisons were m b ae dt ew e^ n u e i e s derived fro, relatively The original stocks were mostly ol strain^ culti A vm ae r ci can Indian tribes, specimens of which wer K ee m sp ut po pn l. i e Tw _e yn ty •­ tw •o alleles with colored aleurone and colored pi effects (Rr series) wore included (abstract in In a 'd • d Jit i io nn aa ' number of alleles of the r series 472 later parallel study. The effect of different R alleles upon plant color t o d ib fo ft eh r si n wt ie dn es li yt ,y and distribution of pigmen a ts as to ic oi nat ^e d S ii nn cd ee p te hn ed ent effect upon aleuron l ei n ck oe ld o r providesm a ar k ce or m, p li et t ei ls y possible to identify d eu ve e n very to R sl igh tt h de i ffea rl el ne cl ee ss , as distinguished from the effects of modifying factors. The series is non­linear, in that various case a sl l oe cle c urp ro id nu c we hs i cd hi s ot ni e nctly more effect than anothe a rn d u pd ois nt i sn oc mt e ly t il se ss us e s upon others. Such cases might i f b et he e xa pl el ce tl ee ds td o if of ce cr u r only in the extent of th s ei in rg l ee ffr ee ca tc t ui po on, n sof mo er it might be expected that i pn ic gr me ea ns te a tw ii ot nh w" os ut lr de ngth of action" up to a give a nn d p ot ih na tt at nh ai s t ho ep nt i dm eu lm i np oo ,i nt might differ in the vario T uh se e tif sf se uc et ss o cob ns ce er rv ne ©d do not fit this hypothesi s si mp il ne af no yr m r. e asT oh ne ay b lys uggest rather that the effect p ol fa n Rt ac lol lo er l esi s ua p onc omplex of two or more types o i fn at ch te i os ne ,n s me d ei pn ow nh di ec nh the aleurone color effect and the plant co e lf of re ct are independent. For a major portion of the plant color effect, ho o wf e vd ei rf ,f er the en t r et ai cs ts iu oe ns is quite closely correlated. The b Re a ar lr la en lg ee sd mi an y a single sequence to represent t o hc ec iu rr r ee fn fc ee c ta n ud p oi nn tensity of pigmentation in mes s oe ce od tl yi ln ,g cl oe la ef o pt ti ip l ea ,n d margin, seedling leaf sheath, sh me aa tt uh rs e, pt la as ns te l b ag sl au lm e, and anther. For example, s te he ed li on cg c ul re ra ef n cet ip o f color marks a level beyond wh i is c hd e lv ue ll lo p ae nd t ha en rd cb oe ll oo iw which anther color is dis c to il ne co tp lt yi l we e aa kn .d m Fe us lo lc otyl color are reached below c to hl io sr o lf e vet lh ,e se t ho or ug ga hn s t hei s deepbr and more rapidly w di et vh elti op p edc ol mor . d ie Di ts yt pi en s ct seedling sheath color h i dg oh ee sr nl oe tv e ol c ci us r r ue na tc ih le d a, and is accompanied by deep t eh ne e dt a cs os le ol r ag tl iu om ne s o ia nd anthers. In their effect u c po om np le tx h ist he c hR a ra al cl te el re s studied may be regarded a l se v de il f fo ef r ia nc gt i mo en r, e la yn d i nt he varying thresholds of s t ru ed si ped o np sr e ov ii nd e t ha e s te in ss si ut ei sv e means of detecting differences in th o ef la ec vt ei lo n of the alleles compared. L. J. Stadler and Seymour Fogel 2. New Alleles of A. As previously noted ( t Nh oe w sg e Ln ee t tA e^ r ,m u 1t 9a 4­t 1e :s 44s .p )o ntaneously at a fairly hi r ge hs e rm ab tl ei tn og aa P t. y peT he mutants, identified by the p r po ad lu ^c e a lp el ua rn ot ns e w eh xi fc ch ­ tl ,i ke aP produce both anthocya p ni ig nm en at n. d anN ti hne o xao nf t ht ih ne mutants were checked for t p he er i dc oa mr ip n ae nf tf e cc rt o p wr ne sent in and a^, and all showed this effect also. In plant color with 3 and Pi, the mutants w d ee re ep l iy n c go el no er re ad l a mn od r em ore reddish than the standard aP. r at Th he er y w vi ad ie il ey d in degree of redness, ranging from m a ar o do en e ps h ba rd oe w na p tp or o aa ching purple at maturity. T a hn ed ov ra ir gi io nu as l o mt uh te ar ns t sw ^h ich have occurred in later experiments with A , 473 form an apparently continuous series between the two extremes. No n o uf tA ab n to a colorless aleurone type or to a type producing only ant x ha on ­t hin pigment in the plant has been found. Four representative mutants wore selected for fur d te ht ee rr m Bi un ue a yw ,h et th o er the differences in expression were due i n tt oh e d im fu ft ea rn et n ca el ^l eles. The factor et, an X­ray induced c m hn rb o mn ot s oml eo ca 3 ted 11 units distal to A, was combi m nu et da n wt is t ha n od n ea ls oio w tni et h standard aP, and the phenotypic effec •i tn sb a wc ek rc er o cs os m pp ar ro eg de nies in which the various alleles £ co up ll da n bt o c co ol mo pr ^ r( ^with 8 and PI) in sib plants. The re t sh u/ lf to su r s hm ou wt a tn ht as t represent distinguishable alleles oi a A ,m ix et aur ce h pof r oa dn ut ch eo sc yanin and anthoxanthin pigments but d r iel fa ft ei rv ie n gq u man t ti ht ey of anthocyanin produced. These are des m ia gh no ag ta en dy (Ab­m), cedar (Ab­c), chestnut (Ab~ch) und walnut (A ­w). The aleurone color of the mutant A01s described, as i e dt e­ nm ta ir fk ie ed d s ie ng regations, is paler than that of A or A, but no ^ o sa oP . P ­­*­ S ^eed separation may be made effectively in seg e ri et gh ae tr i oA n so r agu aP. i nstT here is also a r­.cognizable differe b ne ct ew ee in n aso lm ee u ro of n e th ce o lm ou r tant types, which sometimes is distinct enough i in od ii vidual classification. There are some interesting differences in the action a l oe fu ro tn he e sm eu t pa an let s of Ab and the two pale aleurone mutants a ro as te hf ar no dm wo ht ih ce hr members of the A series. A ( i Ns e wa sn Lu el tt tr ea r­ ,v i 1o 9l 4e 1t : m ­u +t Wa nt of A, which has a pale al p eu ur rp ol ne e p al na dn t r ec do dl io sr h, yielding anthocyanin and anthox i as n ta h im nu t pa in gt m eo ntf , .a , Aw hich occurred as a sector with pale i n p ua r pp ll ea n at n to hf e ra s Dt B PI Rr. It also produces r e pd ad li es h a lp el ua rn ot n ec ol ao nr d, a yielding anthocyanin and anthoxanth t ie ns .ts s >qh uo aw i ia t ad .i is vt ei nct differed in ohc anthocyanin produced by A and A", on the one hand, and by Ab­m, Ab­c, Ab­eh, Ab­w, and aP on the other. The psle Ab mutants, like aP, show little or no diff a el re eu nr co en e i nc o tl ho er of homozygous seeds vs. seeds he tea os,) ­ ous lor a* o and Aw , in selfed ears of plants heterozygous for a, c um su hl oa wt i cv le e ae rf lf ye cts, the heterozygous seeds being disti t nh ce t lh yo m po az ly eg o au ns a scads often being indistinguishable from full A. In compounds among the pale Ab mutants and between these mutants and aP the plant color effect of the redder member is dis a tn id n ci tn l yt h do os me i nc aa ns te ,s in vrhich aleurone color is distinguis t hyp ae b li es td ho em i dn aa rn kt e. r Abt produces a redder plant color than the A mu^n s or aP, but tha hybrid Abt/ap is intermediate, with a pronounced increase in anthoxanthin content. A1 1 x aP/a yields progeny of two very t dy ip se ts i, n ct th e Alb/ap plants showing a distinct dominan a tn t eh fo fx ea cn tt h oi fn ap dr o od nu ction as compared with the A^ya sibs. This dominant effect of a.P is not evident in crosses with A or a p 4p be ,a r sa on c fe a ro f a st h te n ep lants is concerned. It is evident, however, m crosses with Abr, a Dt­mutant obtained by Rhoades, (News Letter, 1941: 6) 474 hich resembles A in plant and aleurone color but does not give red \ricarp. In crosses of Abi x a_P/a there is a distinct diminution of red and increase of brown in the plant color of Abr/aP vs­ ADr/a sibs. ^similar effect is shown by cedar, chestnut and walnut, the only A mutants tried in this combination. It is wholly absent in A x A /a, the Abr/Ali: plants being indistinguishable from the Abr/a sibs. 3. The Action of R and B. No anthocyanin pigment is produced in maize except in the presence of suitable alleles of Al, A2, and either r or B. For certain tissues B will serve as well or better than R; fnr others R is essential regardless of the presence of B. In those tissues which may be colored by the action of either R or B, the essential qten in anthocyanin synthesis ­which is accomplished by R must be accomplished also by B, or it must be made unnecessary by some alternative step accomplished by B. The effects of varying R action are shown by the phenotypes of the various R alleles, and a similar comparison may be made for B by comparing it with the weakened B alleles described by Emerson in 1921. Several additional B alleles intermediate Ln action between B and b have been^ picked up in exotic strains and in dent corn varieties. Their study is not quite as convenient as that of the R alleles, but is facilitated the use of Anderson’s chromosome 2 inversion to intensify the linkage v/ith seedling markers. The B alleles, like the R alleles, differ in tne_ occurrence and the intensity of the pigmentation of various organs, and in their major plant color effect they may be arranged in a single sequence of increasing strength on the assumption of different thresholds of response in different tissues. The order of response of the different tissues is however quite different from that found for the R alleles. The standard B used produces rather strong pigmentation of the seedling loaf sheath, coleoptile and mesocotyl, and deep pigmentation of the mature sheath, blade, culm, tassel, and cob. With successively weaker B alleles, blade color is restricted to the midrib and soon disappears, sheath color becomes weakened first in the lowermost sheaths and last in the middle sheaths. Glume color diminishes first at the tip region of the glume, and with successive steps is limited more and more closely to the base of the glume. In the weakest allele distinguishable from b, plant color is limited to a narrow transverse line at the base of the glume and to scattered streaxs of color on the culms and sheaths of the middle internodes of the plant. The pigmentation of mesocotyl, coleoptile, and seedling sheath disappears early in this sequence, and most of the alloles give wholly colorless seedlings. The response of R and B genotypes to sugar feeding of excised tissues (Sews Letter 1942: 31; Amur. Jour, rot., 29: 17s) is sharply different. Sib plants of rcb b and 3 ry (with Al, A2, Pi) art about equally colored in coleoptile and seedling leaf sheath. In later growth the latter becomes much more deeply colored in leaf sheath and blade. Excised leaf, sections of the rcb plants, in seedling or later stages, produce anthocyanin abundantly v/ith externally supplied glucose, the amount of anthocyanin varying with the glucose concentration. Seedling leaf sections of the If 475 i nroduce 5 no anthocyanin, regardless of the glucos, ce e c t ci oo nn cs e nt ta rk ae tn i oa nt , a stage when antho t cyanin iW s be i: n? go ‘ p; rn oo d ue cf ef de c mt of added sugar upon the i rn ad tu ec t oi fo n a. n thT oh ce y ap nr ie ns ence of B in addi p tr i o' n n tf o r/h does m nt oh to c iy na cn ri ean s ep ro td heu ction by the excis 3 eS d u l? ean f o sf e cB t iot no s,w ea ak ne ar ta hl e leles of R, which produce anth r oat ce y at nh ia nn ar tc E a, ld oo we es r not increase their response to added glucose. C t ' i r l l u T U.S.D.A. and Cornell University 1 The number L, trisome is now availabl , eu il ^ 1 n a A s? ts oo c, k seg ro ef g at he other trisoi.es, with the ar ee x ava ci ei pa tb il oe n i on f v ni ug mo br eo ru s 1 ,s tock cytologic.ally determined to b B o c fh ^r eo em os oo f mes. To make these triso t mh ie c c so tr on c kb se l .t .. oa ren d s de ^lse ^whe ir fe f, the ty have been outcrossed zo diffe U ren ntc i a l inbred lines, inc s lom ue dw ih na gt earlier maturing New Yorx State linoi oi Luces 11. 2. The embryo culture technic was t uP tt ir la in zl eo di d toc or on b ta an id n totraploid Tr ti p dsacura. Tetra w pi lt oh i da cm oi rx nt u vr ,e a s o pf op lo ll il ne gn af rom An corn and Un T t rh? i ph su as ck us m a bn yd ss tp rr ii pn pk il ni gn g c the pollen over th ,, e i sr i lp xn st i er xe p ol se en dg t ih h. r ouT gh he o husks were then drawn p u p aoor ui tt h t hr eu b .b ae rr sb ha on ods and a glassine bag ^ o tor a pt rei vo en nt. exE ca er ss s ip vo el linated in this manner w a ef rt ee r h ap ro vl el si tn ea dt i io dn , t ot h ae e om ab /r .y os of the e px ac ris te id a la ln yd dt er va en ls of pe edr re kd e rnto e la s s ">lt ee ‘ rile agar nutrient medium in 2 oz. botUes. f ? : rek ^rtdh?rp:ys?rth t X :i id ms a Lre rs xti °ll s -making exclusively vegeta e tv ii vd ee nc ge r oo wf t hs ate nm d se hl oo wn g na ot ion, although they are s S ti un rc de y , th he es ae l tT hr yi p Ps ^a na tu .m .­c orn hybrids, unlike th M oa sn eg e pl rs ed vo ir of u sa n yd oR eev ^es, have two sets of chromosomes t fh re oy m s eh r.o cu hl d p ab re e nh ti ,g hly fertile; but this remains to oe seen. 3 Tetranloidy may be induced in the shoot apex of very young maize . « ! « . W .ou. the cut end of the primary seminal root, a of rt e lr a tt eh re is ne condary seminal Vroots are e c so tl ac bh li ic si hn ee d s bo yl u ^ti ^o un et ihr no gug h the base of the epicotyl o ff o lt lh oe w is ne ge d e. x ciI sm im oe rsion alternate h lou yr ip ne r .i 0o 5d $s , c ou ls cu ha il cl iy n e fo ar 4 n day es , effe vctively i n i dn u ct ei ds s su ie z et ah ba lt e p se er cs ti os rt se d o ft o maturity and affe s ch to eo dt . b ooI hn ts ao sm se e' li n .s ­nt oa n ec ae rs both ear shoot and e tn at si sr ee ll y a pt pe at rr ea np tl lo yi d w, e .a en d selfing such plants E px rt oe dr un ca el d a tp ep l ri ac pa lt oi io dn s s eo ef d .c olchicine to ear­shoots and seedlings prove 476 gptisfactory as a practical method of chromosome doubling. This seedling treatment technic is being adapted to the production , ^­oloidc from haploids in an attempt to obtain homozygous diploids from heterozygous maize stocks, especially commercial hybrids, m one generation. / The origin of the perennial rhizome habit of Euchlaena perennis mtrh 'has puzzled students of species relationship in the tribe Maydeae enr many years. All other American representatives of the tribe are !nnuals with the exception of Tripsacurn, which is perennial but grows m dense clumps and has very short rhizomes unlike the elongate freely­ spreading rhizomes of perennial teosinte. The annual teosmte of Central America and Florida that has been examined cytologically is diploid. The nprennial teosinte, known only from one very restricted area in M exico, L tetraploid and has multivalent synapsis of its chromosomes and other­ characteristics which indicate that it is either a true autotetraploici or an aliotetraploid of two closely related species or ecotypes. Diploid forms of perennial teosinte and tetraploid forms of annual teosinte are unknown in nature. However, a somatic mutation from the annual to the perennial habit occurred in a plant of' Durango teosinte grown in the greenhouse in 19 3 1* The annual portion of this pl­ur., (1359—10) was diploid and its selfed progeny were diploid manuals with the exception of one plant (1625­B­l), which was tetraploid and perennial. The perennial rhizome sector of plant 1359­10 was propagated vegetatively, and several root­tips collected from it soon after it was discovered were examined cytologically and found to be entirely tetraploid. However, of 15 seedlings produced during the following flowering perioa frOia _ i selfed seud of the perennial mutant one was triploid and l^were tetraploid, and the mutant pollinated during this period by ictraploic^jorn produced 11 tetrup'loids and one triploid, suggesting that diploid tissue persisted in the mutant sector up to the time the first crop of seed was produced sufficient to form at least 2 female gametes with a monoploid set of chromosomes. The spontaneous occurrence of this some.tic mutation from the annual diploid to the perennial tetraploid condition was interpreted as strong evidence in support of the assumption that L. perennis was simply tetraploid mutant of E. mexicana. To test this assumption further, tetraploidy was induced experimentally in stocks of Durango, Chaleo and Florida teosinte with the heat­treatment technic. These artificial tetraploids had the annual growth mbit of the parent diploids and exhibited no perennial characteristics whatever. Another test of the relation between tetraploidy and the perennial habit involved the identification of parthenogenetic diploids in the progeny of E. perennis to determine whether they would be annual or perennial. In diploid maize parthenogenetic haploids occur with an average frequency of about 1 :2000, and in tetraploid maize parthenogenetic diploids occur with an average frequency of about 1:1000. Data .from greenhouse material of perennial teosinte (teosinte is a short­day plant which normally floaeis during November in this latitude) accumulated during the past 10 ye^rs 477 , +Vin+ hanloid parthenoge i nn edi sc ia st e is ext. remet l y t rh ae r er e iE nu i tts h iso f sw peh ci ic eh s .a re ̂summarized in the accompanying perennial teosinte were need, including f 'n ^n cT ur lhi tz uo rm ees collected at the type locali f t yd i ii nn p . ff or xo icm v s (ee Ud 6 h ja .r jv )es , t ■e * d from the type material p r io ng e Mn ey x io cf o E1 U6 1- 35 15 5 Jj( )2 ,6 60), selfed prog 'n ei nn yt a on fe ou Es L 3t -e 5t ^r 3 ap (l 2o oi 6d l ),m utant (1359-10) and the tetraploi (1 d 62 s5 eedlB- il n) g from the annual portion of this plane. Seedling progenies obtained from various perennial toosinto X diploid corn crosses, 1932­1941 Perennial teosinte stocks 2660 2661 3449 E13­533 E16­515 1359­10 1625 B­l 16­515 13­533 2661 Mi sc. ---- 1 selfed selfoa selfed­ ­­­­— — “ — " 1932 15 80 42 1933 1023 1417 1934 565 126 317 1132 1 14 1 428 1935 570 860 875 734 1040 415 1936 149 1263 166 22 117 1156 1937 16 1410 142 34 1081 137 1933 91 1345 310 47 265 1524 1939 1125 263 44 1695 397 1940 134 405 11 68 2490 20 1941 177 1143 320 43 754 39 140 Total.s 2745 9179 2614 1359 3451 9502 306 705 Grand Total 29,369 Perennial teosinte is propagated vegetatively with a n id h on o g rd ^i tf ef ^i tcu ^l ot iy is experienced in maintaining m­l i in Vd ie .f in ­i te ­l y ­! 7To facilitate the identification ^ individuals in tbs Seedling st c ar go es ,s ed with corn pollen pof g Pth re ,,c ronstitution a AB ­PI i1I 0 iRT *h »e f t «ri ploid hybrid seedlin u gn si pu j. nder sui ct ra ob wl oe ­ w' c *ultural conditions could b r oo a dd iL si t/ i nf gr uo im s hm ea dt ernal, weak sun­rei seedlings. Parthonogenet s ie cedlings of paternal orig a it n m wa ot uu lr di t by e or e itg hr ee re n liguleloss. One dp in pr lt oh ie dnogenetic maternal dip: 478 £LPv CO ­vi­ 'md one parthenogenetic paternal haploid were identified 2 a9 m o8 n6 g1 ts he ee dlings from the perennial teosinte X diploid „ co om rn cross ed su ring the period from 1932 to 1 9 U inclusive. Th d ei pl mo ai td e ra np ap le ared in the 1936 progeny of culture 2661, which c io nn t ta hi an te d y e1 a1 r5 6 seedlings. This exceptional diploid had Gr to hw et h a nh na ub ai lt . It tillered profusely, but produced no rhi f zo or mm ei sn g a na a f ae fw t ea rb orted tassels the plant died at about the sa t mee os ti in mt ee ap nl na un at ls of the same age mature and then die. The p h aa rp tlo hi ed n ogof e np ea ternal origin had narrow leaves and otherwi t se eo si rn et se e mi bn l et dh e early seedling state, except that it w a s a s de ie md ili nn ug t ia vn ed had the purple color of the pollen parent; l i at t eb re c mam e o nt ty op gi ec na yl ly maize­like and was indistinguishable from ordinary maternal haploids of the same stock. In addition to these two exceptional seedlings there occu y re ra er d a e as cm ha ll number of maternal tetraploid seedlings. Th f ei sr es t w ea rs es u am te d to be contaminations, but the prevalence r ae mc oe ns gs i tv he e mc h ol orophyll mutants suggested that at least h sa ov me e o or fi g ti hn ea mt e ^d f rom unfertilized, normally­reduced diploid eg b gy s c fh or lo lm oo ws eo dm e doubling in early embryogeny. If this is h w ao pu pl ed n ih ne gl ,p it to explain the low frequency of maternal diploids obtained f this perennial teosinte X corn cross. The perennial rhizome habit of E. perennis does not behave si ar sa o al e Mendelian recessive. The Fx perennis X Xn corn is i in n tt eh ra mt e dii at tec an be maintained by careful subdivision and o p cr co ad su ic oe ns a ls lh yo rt rhizomes. The character does not segreg a an td e b sa hc ak r­ pc lr yo s is n pr 2o genies but behaves like typical quantitati t vh ea t c ha ar re a cd e ep e .n dent on the interaction of multiple factor s se .g reg Ia nt i wn ig e sp e rogenies most of the plants tillered much more t h Pa rn o xd ui sd e t yh e kn corn parent, but very few developed any a r ph pi rz eo cm ie a bs ly es tem during the summer season. A much .Longe t rh a gn r ow we i nh ga v oe C ca ot o nI thaca is needed to make really satisfactory c f lo ar o sr ih fi iz co am te i oh abit in material of this kind. However, it is f ro am p path re e n.g eneral character of the segregating populations i n at ne dr m te hd ei ate nature of the Fx plants with respect to rhizome a hd ao bs ia tg se te hf af te ct is involved, and it is therefore conce c iu vm au bl la et iv te ha tg ene action accompanying chromosome doubling might a tn r aa nn sn fu oa rl m into a perennial in the prosence of a suitable genotype. Some such interpretation of the origin of the per h ea nb ni it a lo f r hE i. z op me er ennis is supported by the occurrence of the par m ta ht ee nr on ga el n ed ti ip cl oid lacking the perennial rhizome habit E . i np e tr he en n pi rs o, g ea nn yd oby the occurrence of the spontaneous per c eh ni nm ie ar la , i tn e ta in a pa ln on ual plant of E. mexicana. The persist h ea nb ci et o.i n tt hh ee ae nx np ue ar li mental autotetraploids of E. mexicana s mt ao yc k ms e af nr o tm h aw th i tc hh e they wore produced lacked the essential g t eo net sh e rp eqr uo id su ic ti e on of the perennial habit in the tetrap g le on ie dr a cl tl ay . eb .e ^ li 1e ve id s that most annual forms of teosinte pos o sf e sm sa i az de m ig xe tn ue rs e. s This would provide ample opportunity o ff o rg e dn ie ss p lo af c ea mn en nu ta l teosinte having perennial prepotencie wi st h b ys t mr ao in zg e a gn en nu ea sl prepotencies and would account for th th ee ap pe pr ee an rn ai na cl e h 0 abit in some annual teosinte tetraploids and not. in others. L. F. Randolph 479 Institute Experimental De Agriculture Y Zootecni E al Valle, D.F., Venezuela 1 Corn Breeding in the Tropics. Per s ho ar pn s d ae e fd ei wn g o bsi en r vV ae tn ie oz nu se l oa n, latitude H 12, would be g e on fe t ii nc ti es rt es s t to in other parts of the world. A preliminary survey of the existing corn varieties in Venez m ua ed le a in September, 1939, revealed t p hr ao td uctive capacity with a te ann dd e sn ec t/ ^ to h e^ primariiy because S peopl^depend to a large extent on W of a small, thick pancake, for foo s do *m e regions o „ f ;£th fc e moc ro eu nt 0r 0mnonly u F yo ,r by ue ta r w sed, s h, n .e ga ■ tiv ie “s election h ba es c ab ue se en tg ho ei n pg e oo pleea nt mth e cob re ns t oeseeds and plant the leftovers. Some of the best varieties and hybrids from the U n i t e d States and from many tropical and subtropical d anFplanted together The types from the United States were vigorous m the seed! g - „ s , . . . fZ S . D £r ZAr *tu £ » ro $Ro Lque \, &wa .; ­ » s vig «or -ous ' i «n *the ■ TrS; £2riSTand l sat ee er d* l0 iv ni gg o sr ou gs ,a ga *in and produced restively ^ r g y a Ve rn sez .u el Ta hn e varieties gave their usual rank P des ^irab \le £ear as. lA kyel lo ofw seeded type m fre od miu m height f set tt hw eo ^ ro oa ur ns d .at t Th he i sp r o p * ^ e r teste M S S ^ vely t ° i : ^ e the most popular varie —ty in the country in spite oi its color. Its origin is interesting. A representative fr c oo ml l te hc it se d gotw vo e rnv ma er ni te ties from Cuba in 1938, but t ^ her e s em ei dx s ed o f in h e and «l °ing. About two years l s ae te ed rs were salvaged from a teg of woevil­eaten s eeds the present s b elec is eing t id oi ns t hr ai sb u bt ee ed n in e vt ah is co * untry and . in o ot uh ne tr r in ee si g uh nb do er ring counc t rh ie name of VENEZUELA­1. The main project is the development c ol fi m ha yt bi rc i dc o cn od ri nt i ao dn os p to ef d V te on te hz eue la. Six generations of h ̂e it ne r rog ee ^ne dou ^s lm la nt ce sr >ial s om he a s of r esw uhi lc th e d h ia nv e a desirable appearance ^ toperosees a n ad n us i hn ag vl ee dc or no es s we es. l l iT nh e cof pi rst douole crosses are now being tested. It i= interesting to note that most V oe fn e thz eu e vl ara i^ e tt iee sh L c oc lo lu en ct tr ei de s f ro of m this latitude deg i en nt ee rns ativ ee rain pb ir de le yd ^i wn ig t. h Outcrossing followed by sib crossing 480 accepted as the best practice for utilizing these varieties. The Cuban type is a striking exception to this rule, ^elo­ing has resulted in a multitude of types, but most of them are relatively vigorous and some are exceptionally impressive. Inbreeding has resulted in the usual number of hidden recessives and the isolation of new mutations. Male sterile, barren stalk, brown mid­ rxb, virescents, white seedlings , zebra, tassel seed, cuscoid, and many others have been observed. A small but important change in breeding technique has been necessary due to the larvae of an octitud fly, Euxegtq stigmatia Loew. It is not advisable to cut back the husks of the ear shoot to obtain a uniform brush of silks because the insects enter and destroy the ear. It is better to wait as long as possible for the silks to come out nature, y before pollinating. There can be no doubt that in the near future hybrid corn will be available for distribution in a country which has no seed companies and little knowledge of seed improvement. In the meantime, however, she type VENEZUELA­1, improved by mass selection, has been widely distnoute . 2. Sweet Corn in Venezuela. The mutation to sugary corn which occurred in a variety of dent corn adapted to the climatic conditions o Venezuela (Maize Genetics Cooperation News Letter, April­1, 1941) has Deen the basis of the development of sweet corn in this country. This corn has been named VENEZUELA­2 and is now widely distributed throughout the entire country and in other South American countries that have requested it Some of the details of its­ development may be of interest. Until 1942, the majority of the people in Venezuela had never tasted true sweet corn and most of them had never heard of it. Some who had travelled in the United States, imported seeds of a few varieties and planted them in Venezuela, but the plants were always weak, badly diseased, attacked by insects and consequently unable to produce ears. Corn knovm as "jojotos" has always been consumed in Venezuela and is sold in the markets of the cities. This is the native type, a mixture between dent and flint, that is harvested not in the milk stage but in the soft dough stage. It is eaten directly from the cob or cut off and used to make certain Venezuelan dishes such as "cachapas", a pancake­li .e preparation. The true sweet corn now available in Venezuela has such a contrasting flavor to the dent­flint mixture that it is widely accepted by the people of all classes. In 1939 when a modern program of corn improvement was initiated in Venezuela, approximately 3,000 self pollinations were made in the best local and imported varieties to develop inbred lines. Some of the first generation ears were planted in progeny rows in 1940 and about 3,000 of the best plants wore selfed. None of these second generation cars segregated for sweet corn. Biiu one of the second generation plants gave, on selfing, an ear with 216 starchy kernels and 73 sugary kernels. Five plants in the same progeny gave ears with only starchy kernels. 481 „ there had been no sweet corn planted anywhere near these fields and ‘T s u g a ^ kernels had appeared In the first two generations of inbreeding, H is extremely likely that this was a mutation to sweet corn. Fortunately, it occurred in one of the moot vigorous lines whi ho cd h such desirable characters as deep green color, relatively ear m lat yu rity, two ears per stalk and, most important of all excellent hu.k covering of the ears. qnme 0f the sugary seeds and the starchy seeds from th w ia s nt eae rd wa en rd e shf­pollimted. As was expected the sugary­ kernels gave ears Pf TQO/o sugary type, whereas some of the starchy f J keZ rnels bre an rd uT thcS segregated sugary. Seeds from the sugary ears w W eh re en these plants had tassels and pollen, a field ^ oi f tt hv e' o oi ngst ie nr ac hy corn was nearing the completion of its flowering ^ p pl era in odt ,s itT this field were pollinated with pollen from the sweet co i rn nb red. The seeds from these ten ears were mixed and plant f ei de l id n a at st he 1 Instituto Experimental de Agrieultura y Zootecnia in unua y, ­in/p. Vigorous plants were obtained. There was no attemp t he p 0 ol cl oi n nation/ All of the ears segregated approximately 25 per cen sugary kernels. The sugary kernels from these ears were planted in one field an t dh e starchy kernels in another. There was no attempt to control ­ ­ pollination in cither field. The ears harvested from the first field were of the sugary type, b ut there was considerable variation in the kernels, come e °n ft i ^r eel my wt er ra en slucent while others showed various degrees of starchines.. In the second field where theoretically one­third of the seeds pl w ae nr te e dh omozygous starchy (Su §u) and two­thirds heterozygous for sugary (Su su), the expected ratio of starchy to segrega ing ear^ Actuall . y, • there were 9,3A7 ears with all the kernels starchy and 22,H 7 cars segregating for sugary. Theoretically, the segregating ears should have had a ratio o t fo 51 J usu kernels. One hundred of these ears taken at 2 r0 andom g^ve fr ro am t ios Su • 1 su to 3 Su : 1 su, but the total count wuo 39,74* Su kernels fSd'9,099 su ke^els, » a ratio of f r 4o ,m 3 65 : : 11 . ra ™tio is probably due to a position effect of the plants in field. On October 7, 1942 a demonstration of the history of swe i en t V ce on re nz uela was made to an audience in the auditorium of she V e Sn oe oz io el da na de Ciencias Naturales. At the close of the demonstr p aa tc ik oa ng ,e s of the new sweet corn were distributed to all prosen... .on siderable seed has been distributed since then. From a scientific point of view this sweet corn will not m ba e xi om fu m yield because it is the third generation of a cross betwe i en nb r ae nd line and a variety. In spite of this, however, it d i is st r bi eb iu nt ge d because it has yielded sufficiently well to give the public a taste of sweet corn. 482 Since the first ear of this corn was discovered it has been crossed •+h a number of selected varieties of ordinary corn which do well under L climatic conditions of Venezuela. The plants from these numerous crosses have been self­pollinated, and inbred lines are being developed L n number of typos. When there is an abundance of inbred lines involving the sugary gene, they will be crossed to give hybrid sweet corn for Venezuela. In the meantime the other topeross type will be propagated. D. G. Langham Harvard University, Cambridge, Mass. Studies of chromosome knob numbers of the maize varieties of L­tin­ America have been continued with the following results: No. Range in Ave. Knob Country Varieties Knob No. No. Brazil 3 5­9 6.6 Colombia 2 12­13 12.2 Costa Rica 4 10­12 11.0 Cuba 6 11­12 11.2 Mexico 33 4­13 10.0 Nicaragua 15 9­14 12.3 Panama 4 12­H 12.6 Paraguay 5 2­6 4.3 Peru 15 1­2 1.3 Although the sampling of individua] countries is still far from adequate, the data tend to support the previous conclusion, that low­ knot) varieties are confined in Central America to beseem Guatemala an t do the immediately adjoining regions in Mexico. In ail other parts oi Central America and Mexico and in Cuba as well, only high m o jane have been encountered. Western Guatemala and the adjoining fa Ch 0 iapas in Mexico continues to appear to be the center of maize diversi y in Central America. It appears also that Paraguay must now be added to Peru and^Bolivia as a region of low­knob varieties in South America. Although oni> fiv v ea rieties from Paraguay have boon examined cytologically, the majority oi varieties collected are of the same general type as these and vail probably prove to have but few mobs. Dr. Hugh C. Cutler has now spent more uhaii a year in Brazil, Paraguay and Bolivia collecting native corn varieties and searching xor wild maize. His first goal is being successfully achieved; the seco i ns d still elusive. Several reports of maize growing in the wild ha b ve ee n investigated with wholly negative result.;. Ihe ,ild maize in c a es ^e c was either cultivated maize obviously escaped from cultivation or not maize at all. The cultivated corn collected from Paraguay ana 483 Southwestern Brazil i>j of considerable interest. The cobs^are quite flexible; the pedicel os n bot h staminato and pistillate spike'lets longer than normal. A variety of maize obtained from Amnntina Island in Lake Titicaca in Peru at an altitude of about 12,500 feet, probably the highest altitude at which corn is grown in any part of the v/orla has prove he "early and cold­resistant. These characters may make it valuable plant breeding in spite of the fact that it is very susceptible to smut, p_ n. Manpelsdorf and James Cameron 484 Maize Publications There is presented here a partial list of publications on maize M.J. Murray and R. Morris Anderson, E. and F. D. Blanchard ­ Prehistoric maize iron. A Cn ad n onA m Do er l. JJ uo eu rr t. o .B ot. 29: 832­335­ 1942. and H. C. Cutler ­ Races o ­ f ­­ Z­ ea' a Mn ad y sc :l ass Ii ­ fi Tc ha et ii ron. Missouri Bot. Garden: Annals 29. ->) _ and H. 0. Erickson ­ Antithetical dominanc ­ e­ ­ i­ n m Na oi rz te h. " A mP er ro ic c. a nN ation. Acad. Sci. 27: 436-440. 194 • Andres, J. M. and P.C. Bascialli ­ Hereditary charact m ea ri sz e o fi n c uA lr tg ie vn at ti en da . Genetica 2. 3-2U L-'“ L. , , r C J Berger and B. Shalucha ­ AV Ae ur xy id nu r ci on ng t‘ eo nn t t og fe n my a! i zeF r ko em r np el la snts of varying heterotic vigour, J ou Ar m. e rB .ot. 29: 765­772. 1942. ­ Auxin storage as relate e dn d to o sperm type in maize. Bot. Gaz. 103: 306­3.j8. 194­2. B­iir R, A. ­ Climathological measurements for use m B , theJ a pl rz eo d iy ci te il od n. ofE cology 23: 79­38. 19*2. Bryan, A. A. and J. E. Sues ­ Hereditary characters of maiz J eo ;u r K. n oH te tr ee dd i Lt ey a f3 .2 : 343­34­6. 194­1* _ u _Vi + n V Purtis and J.I. Shafe Cl r! ,l ri JC rb .e h2 ­v i So tr o mat to alinbred ^ d ' h ^ t o mnize. Amer. Jour. Bot. 28: 537­541. 1941. Darlington, C. D. and M. B. Upcott ­ The acUvity of^ine i rn t Z ce ha r om ma oy ss o. m esJour. Genetics 41. 275­2>b. 194­­L. ­ , T v Cvtoloeical studies of toxici r to yo t is n' mof e' rz ie sa t eL m y cs e. l ls II o. f The effects of lithium chloride. Da Pk ro ot ca . A Sc .a d. Sci. 21: 65­87. 1941. Elliott, Charlotte ­ Relative susceptibil d ie tn yt tc oo r In y ti nn ib ir me d rs o. o t Jour. Agr. Res. 64: 711­72;. 194/. ­ Bacterial wilt of dent corn hybrids. Phytopath. 32l 262­265. 1942. ­ A Pythium stalk rot of corn. Jour. Agric. Res. 66: 21­40. 1943. single crosses. Jour. Amer. Soc. Agron. 35: 60-65. 1943 • 485 Hpnrv G, F., E. E. Down, and W. D. Baton ­ An adequ ° a te pl so at ms p lew it ofh cr oe rf ne rence to moisture and shelling percentages. Jour. Amer. Soc. Agron. 34: 777­781. 1942, Ho W. C. and J. M. Koepper ­ Host response of maize 9 seedl ing gr sa m ti on i Pc yo tl hu im u. m Abst. in Phytopath. 32: p. 9. 194/­ Hoi ort, J. R, ­ 33 years breeding corn. Seed World 51: 116-118. 4942. Horoe P. E. ­ Relative prevalence and geographic distrib e ua tr i or no t o ff u vn ag ri i oi un s the 1941 corn crop. U.S.D.A. Plano Dis. Hep 2 .6: 145­149. 1942. Houseman, E. E. and F. E. Davis ­ Influence of distribu an td i ont em ofp er ra at iu nr fe a llo n corn yields in western Iowa. Jo u i . Agrio. ... 65: 533­546. 1942. Huber, L. L. and G. H. Stringfiold ­ Aphid infest c ao tr in o na s o fa n s ti rn ad ie nx s t oo f their susceptibility to corn borer attack. Jour. Agric. Res. 64: 283­291* FA+2. Hull, F. H., J. D. Warner, and W. A. Carver ­ Corn vari a en td i ec so m a ndi m hp yr bo rv ie dm sent* Fla, Agric* Exp. Station. ;U • see. - ' * 'T Jenkins, M. T. ­ Reports of 4th and 5th Corn Improvemen N to r Ct oh n fC ee rn et nr ca el s Re og f ion, Washington, D. C. (mimeographed) it­h., ieA­. Johann, H. ­ Origin of the suborizod semi­permeable membrane c a ir ny o tp hs ei s of maize. Jour. Agric. Res. 64: 2/5­/8­­» Jones, D. F. ­ Growth changes associated with chromosome aberrations. Abst. in Gon. 28: p. 73. 194.''. ____________ _ Chromosome degeneration in relation to growth and hybri v digor. Proc• Natl. Acad. Sci. 28: 33-44. 194*-* ­ Natural and induced changes in chromosome structure in e mn ad io zs ep erm. Proc. Nation. Acad. Sci. 27: 431­435* H'l* Keller, K. R. ­ Evaluation of some morphological ch r ae rs ap ce tc et r st o o ft h ce oi rr n u mse in forecasting yield. Jour. Amer. .00c. Agron. 34: 940­953. 1942. Kempton, J. H. and J. Vf. McLane ­ Hybrid vigor and weight of ge s re me sd s i no f t hm ea ize. Jour. Agric. Res. 64: 65­30. U ^ . Kerakarap. M. F. and W. J. Martin ­ The pathogen l ii cn ie ts y o of f U ps at ii rl ea dg o h az po ln oe i aversus the pathogenicity of numerous mixed ha P ph ly ot io dp .a thology 31: 1051-1053. 1941. Kirieonko, E. G. ­ Selecting maize for low and high weights of core in c to hb e. Jarovizacja 3: 70­7J. 1941* 486 Kirichenko, F. G. end A. S. Musiiko ­ ( ' On im proveof m eB na ti ze seed). larovizatsiia (Vernalization) 1 v.ohlcr B. ­ Natural mode of entrance of K° f ungs iy m ip ntt om s c ot rh na t e ai rn sd i ac na dt e s oi mn ef ection. Jour. Agric. Res. 64: 421­442. 1942 Tindctrom E. W. ­ Experimental data on the probl ' eq mu a on ft i dt oa mt ii nv ae n cc eh a ir na cter inheritance in maize and tomatoes, . a .. in Gen* 28, p. 81. 194-3 • Livingston, J. E. ­ Charcoal rot of corn and sorghum in N U e. bS r. aD s. kA a. . Plant Dis. Hep. 26: 4­0­52. 1.342. Lverly, P. J. ­ Some genetic and morphologic ^ cp hao rp acp ti ern sg a fe fx ep ca tn is ni gon tho ef popcorn. Jour. taer. Soc. Agron. 34­ 986­999­ 1942. M.,+hpr v _ Competition for chiasmata in diploid M “ at nhe dr Z ta ri it s; oc mh ir c? mS al ii zf eo rsch. u. Mikrosk. Anat Abu. B: Ch Z re oi mt os sc oh mr a. : Zellkern u Chromosomen forsch. 1: 119­W ­ >>>* Maxwell, L. R. and others ­ Effect of temperatu s re en s ai nt di v ti it my e o of n m ta hi ez e X ­s re ae yd s. Jour. Washington Acad. Sci. 32. 13­24. 1942. McClintock, B. - The fusion of broken ends of chromoso n mu ec sl e fa or l lf ou ws ii no gn . Proc. Natl. Acad. Sci. 23. 458-46.)• 1942. Mitchell J. W. and Whitehead, M. R. ­ Respons S esi t ofs vf eo gl el to aw ti in vg e a pp ap rl ti sc a ot fi on of extract of pollen from Zea mays. Bot. Gaz. 102: 770­791. 1941. Moulton, J. E. ­ Extraction of auxin from maize, from smut tumor m ^ai oz fe and from Ustilago Zeao. Bot. Gaz. 103: «5­739. —s* Liisr&fsrsErl'' 01 '“*• 19: 45­47. 1942. 0 1 Mara, J. G. ­ A cytogenetic study of Zea and Euchlaona. Missouri Agric E .x pt. Str.. Res. Bui. 341 • 194-. Patch L. 8. ­ Survival, Wight, and location f e oe o fd k i En ug r ope ar ne s ci os rt na n bt o ra en rd s susceptible field corn. Jour. Agile. Res. 06: 7­20. 1943. u(G .. W,1.dete . . VOSrm .0 ltlil i V0Jn . lil., ,a M. SgncohlilXosW. ObCe..r gb a-n-d G.- ing t a T. ̂cB­von tt,ho reduction in yield of f h ngr er ­ T^-, att„0„^„„iel td . hnc o Rlr ln TOco y Deai r n bo e rer u. r o Jour. Agric. Res. 65: 47o-48^. 194- • 487 Patch, L. H., J. E. Holbcrt and R. T. Evenly ­ Strains of P f ieldr es ci os rt na nt to the survival of the European corn borer. U. S. Dept. Agric* Tech# Bill# 823: 1—21. 194­2# ppterson, I). F# ­ Duration jf rocoptivenoss in corn silks. Jour. Amur. Soc. Agron. 34­*. 369­371. 194­2. Rather, H. C. and J. Tyson ­ What effect do commerc t ih ae l fertilisers have m o n maturity of corn. Jour. Amer. Soc. Agron. 35: 43-47. 194u- Beeves, R. G. and P. C. Mungelsdorf ­ A proposed tax t or ni ob me i c change iM na y td ho eae (family jraminae). Amor. Jour. Bot. 29. 815-817. 194­. Rhoades, M. a and Hilda Vilkomerson ­ On t^_anaphase movements of chromosomes. Proc. Natl. Acad. Sc.].. ­2. 4­33 ­ Preferential segregation in maize. Genetics 27: 393­4­07. 194­2. Richardson, J. K. ­ Studios of r it rot of corn in Ontario. 'Jar. Jour. Ros* 20G: 24­1­256. 1942. Roberts, L. M. ­ The effects of translocation on growth In Zea mays. Genetics 27: 584­603. 1942. Robinson, J. L. and John E. Christensen ­ Containers for corn moisture samples. Jour. Amer. Soc. Agron. 34: 59­62. 1342. _ . r n tonvpvitv of sugarcane and corn pollen. A method for Sar long­distance shipment of sugarcane pollen by airplane, user. Jour. Bot. 29: 395­399* 1942. Shafer, J., Jr. ­ Water loss from excised leaves. Amer. Jour. Bot. 29: 89­91. 1942. Schindler, A. J. ­ Insect transmission of wallaby ear disease of maise. Jour, Austral. Inst. Agr. Sci. 8: 35­37. 1942. smrman B. C. ­ Maceration method to demonstrate the vascular system I n Zoa mays. Bot. Gas. 103 : 627­629. 1942. Sommer, A. L. and A. Baxter ­ Differences in growth limitation of certai p nl ants by magnesium and minor element deficiencies. Pi­ Physiology 17: 109­115# 1Q42. Sprague, a. F. ­ Transmission tests of maize natanc induced by^ultra­ violet radiation. Iowa Agric. Exp. oti. Ro. . mi. p faclnUUd. Lloyd iAd.. Trttrr ­ Gen-- e-- r--- a1 l ­ „ ­­ vs. s­p ecific co. mbining­­­­­ahliity­in single J crosses o of / .corn. JTo__u_r_. AAmnieAYr*. CSoocn. AAgrrtrornm.. 3a. 923­932. 1942. Stadler, L. J. and H. Roman ­ The­ genetic nature induced mutations affecting the gene A in maize. Abst. 28: 91. 1943. 488 tadler, L. J. and S. Fogel ­ Gone variability in maize I. Some alleles of series). Abst* in Gen. 2.8°. 90* 4943* ­ Gene action in anthocyanin synthesis in maize Abst. in Amor. Jour. Bot. 29: IV. 194­2. Stringfield, G. H* and D. H. Bowman Breeding corn hybrids for smut resistance. Jour. Amor. Soc. Agron. 34: A86­494* 1942. Swearingen, T. ­ Cool­bred corn pollen. Iowa Agriculturist 42: $0 31 1942. Tatum, L. A. and M. S. Zuber ­ Germination of maize under adverse conditions. Jour. Artier. Goc. Agron. 33: 43­59. 1943. Tavcar A. ­ The immediate effect of crossing small and large seeded genotypes on the character of the kernels of Zea Maya L. To jOpr. Naucna Smotra, Zagrob. 2: 77­96. 1940. Ullstrup, A. J. ­ Inheritance of susceptibility to infection bj ̂ Helminthosporium maydis. Race I in maize. Jour. A g n c . .o*> 63: 331­334. 1941. Valle, C. G. ­ Estudios genoticos Sobre el maiz. 2 La prueka y u tilizacion de las lineas homogoneas. Mem. Soc. Cubana Hist. Nat. 29­36. 1942. Veale P. T. ­ Nutritional information from plant tissue tests. Better Crops 26: 10­13, 42­45. 1942. Weibo, H. D. and Phillips, M. ­ Hemicelluloses of cornstalks. Jour. Agric. Res. 64: 401­406. 1942. Wilson, W. E. ­ Physiological studies of two species of Diplod, a parasitic on corn. Phytopath. 32: 130—140. 1942. Woodhouse, W. Jr. and H. D. Morris ­ Effect of vitamin B on field crops grown on several North Carolina soils. •>car. Agron. 34: 322­326. 1947* Zuber, M. S. ­ Relative efficiency of incomplete block designs using com uniformity trial data. Jour. Amor. Goc. Agron. 34: 30­47. 1942. 489 to III. Inventory of Seed Stocks Propagated in 1942 In 1942 I planted and hand­pollinated only such stocks as were r;ent me last spring or as Dr# Welch told me should be roplonisuee, k total of 140 ears were obtained. Go 42­1 + + p as +/sr ­±­ p + + bm2 . 9 oars#+ ts2 + 11 42-2 + p as jgs/er Pu ­ + + . 7 ears. + / 11 42­3 as/42­1 . 5 ears. 11 42­5 zb6 (from Burnham), 3 cars. 11 42-6 br, smut resistant stock (from Burnham). 3 ears. 11 42­7 A C K Pr cr, brov/n pericarp (from Bumhap). 5 ears. n 42-8 A C R pr cr (from Burnham). 3 oars, 11 42­9 a C R pr cr (from Burnham), i ear. 11 Fo of a C R na­ (from Burnham). 14 cars. it 11 42-12 + + / — ­ (from Burnham). 10 cars. / + + I! 42­13") — lb— —— — /pr Sh wx (from Burnham). 19 ears. I 42­14J + + sh wx v/ I 42­15 Homozygous T3­5d (from Shuman). 7 oars. I 42­16 T3­5d/+ (from Shuman). 4 oars# I 42­17 P gs bm2. 3 ears. I 42-18 P br f bm2. 2 oars. I 42­19 Tu/+. 3 ears. I 42-20 su Tu # 1 ear. + I gl3, segregating ws2. 7 ears. I I su — gl3.“ T 5 ears. I 42-277 su la. 3 I t ears. 42-28J I 42­31 y4 It a c r pr i. 3 oars. I I y4 It/Y4 it. 14 ears. I 42­34/ it 42­41 I wx ygb . 9 ears. 490 Supplement to News Letter 17 Two reports received too late for inclusion with the others Minnesota University 33 Sao Paulo University 33 491 University of Minnesota University Farm, St. Paul, Minnesota 1 . There is an indication of linkage between interchange l­9c (breaks near P3 and wx­13­T), and the dominant white cap (Wc), a small bac­kcross population having: Wc = 12 normals + 29 semisterilec; yellow cap = 27 normals + 13 somisteri'les; or about 35% e.o. ± 5% S.E. 2. Dr. Sprague furnished us with a complete set of his glossy testers. As reported last year, the Cotip gl 10 is the .same as Hayes' gl U (shows 3% c.o. with wx). Tests show it is genetically different from Sprague's glossy 1, 2, 3, 1, 5, 6, 8, 9, 10 (probably different from 7), leaving gl 1 1 and 12 to bo tested. Also: Coop gl 3 ­ same as Sprague gl 3 it gi 5 _ it I' " gl 5 » gl 8 ­ different from Sprague gl 8 3. Crosses between interchanges involving the same two chromosomes were studied for pollen and ear sterility and as a possible source of viable deficiencies. If two are crossed which involve exactly the same loci in the two chromosomes, the Fp should show no sterility. Whore the breaks are not at the same loci, the result depends on the positions of the breaks relative to the spindle fiber. In certain casus gametic combinations should be possible which carry a deficiency for the piece between the breaks. In a series of such crosses, one showed about 20% sterility ana another 25% where the parents crossed with normals showed semisterility. Variation in size of the filled pollen grains was observed. Crosses wi^h genes which have a chance of being near those loci have been made for deficiency tests; also crosses with sifted pollen. 1 . Stocks of zebra­1, zebra­2, and zebra­3 have been revived from some old crosses made at Ithaca in 1929 or 1930. (These will be turned over to the Coop) C. R. Burnham "Luiz de Queiroz" ­ University of S&o Paulo Piracicaba, Sao Paulo, Brazil Since North American colleagues probably are not familiar with the working possibilities in the relatively new Department of Genetics and Cytology at Piracicaba, a few words will be said about it. Our College is situated in relatively flat country at 500 m. altitude and with a subtropical climate. There is a difference between summer and winter, more due to the difference of rain than of temperature. The total rainfall is of about 1 m. per year, but from June to September there is hardly any rain; but morning fogs from the river and heavy dew give still much moisture. Tropical crops grow well in the hot and rainy season (December to March) while cabbages, carrots, sweet peas, snapdragons, etc. grow in the winter and dry season (April to 492 ggptembei) The main crops of the region are sugar cane and oranges, With irrigation corn may be grown practically the whole year around ,lt we prefer, in order to get good ears, consecutive sowings from October bu rlv February, There are only a few fungus diseases, and none of the. t0rious* Insect attacks are generally only of small scale, though e sugar S°nP borer has recently become rather dangerous. The only really serious is the large scale attack by the grain weevils and moth, especially Sow with the difficulties of obtaining naphthaline. 1, Breeding Experiments Ordinary Brazilian corn is composed of extremely heterogeneous and hardly improved varieties. Many of them seem to be equal or even inferior the corn still grown by "wild" Indians. Modern breeding work has been started at Campinas and at Piracicaba. A ­ Sweet Corn (Pedigree breeding): Sweet corn is practically not grown in Brasil and the imported strains which we have been able to observe hardly survive for more then a few generations. *ance I had been engaged, while in England, in breeding for earliness, the scope of o pxoerimont had to be revised completely. Extracts from the­ cro^. ( (white flint) x Golden Bantam) x Banting (Canadian, white early) were crossed Santa Rosa" (white dmt) and with "Cateto" (orange flint) and we have now obtained several good lines of yellow­orange and of white sweet corn, well adapted to field conditions and resisting the heavy rams and wind­, with mean plant height (without tassel): 2 m. mean height of «ir: 1 .2 ■»., time from sowing to silking: 65 days, one or two ears per stalk, absence tillers, mean ear weight (dry): 100 g. B ­ Early Corn (Pedigree breeding): Brazilian corn is very slow in growing, producing generally very tall plants with the ears at about 3/5 to 2/3 the height of the plant. Crosses were made between extracts of "Tirol x Early Canadian" (white flint, 40 days from sowing to silking with Santa Rosa (white dent, 70­80 days to silking) ana F ' n ' f t ­0 ^­7 n0 dd a ey as r lt io n es si "l king.) It was not possible to combine tallness and earl and it was difficult to suppress completely tillering in the early In • Reasonably well adapted lines were obtained with the 45-50 days to silking, plant without tassel, 1.3 m., oar heigh ­ 5 *> , ear weight 70 g per ear. Since the plants are completely different from the local varieties, it seems doubtful if these lines will be acceptable to the farmer, especially since earliness is not a necessity in the State oi S&o Paulo. The experiment was used to study the segregation of quantitative characters and to try out methods of statistical analysis. Some results may be summer!zed: The standard error of distribution can be used as a measure of variability only if the means are of more or less the same magnitude. In order to compare P, F­p, F2, etc.; a weighted measure has to be used. As can be shown theoretically, and has been proven experimentally, the coefficien of variation (standard error of distribution/mean x 100) should not be used, 493 v + instead, a term called the "variance index": (standard error di ofstribution/square root of mean). Using this term, it can be o own or this index that, as expected: (P) = (Fi) (F2) (F3) The segregation for earliness can be shown only by comparin f ga m Fil 3 ies. The inevitable phenotypic variation with an error of more in F2. In studying the relative position (height) of the ear, the ordin c ao re yf ficient of linear correlation r is of no use. T T heL correlati oa nn d oe ra r height was found in all lines, hybrids or segregat ne ea sr ,l y t oc o bn es tant and uoual to 0.6 (positive and significant). Howe » ve ea rr th ho eight"/plant height" should be used and it varies signifi t cf at nh ti lh ye following values: imported early lines 0.20 Brasilian 0 c6 o0 mmerciallines . , some native corn up to 0.7 or 0.3 improved corn 0.5. F. G. Brieger c ­ Inbreeding and Outbreeding: Inbreeding was started in 1936 n t h itenntr Rosa", a commercial variety of white endosperm m ,f te er si sa el n tf io ar l~ .t yh e v0d emon "s tration of the value of the method. Single and d c or uos bs le es are being carried on and a new population composed of sever c ar lo ss ee is n &i is e also being tried. Recently work on orange flint and on orang dent corn was started also. E. A. Graner _ D ­ Population Breeding: Since it was thought that the method of pure­line breeding and subsequent crossing Is a method too c lo os nt gl y n yf o ar n the actual status of maize growing here, an interm i es d ib ae ti en g m et ­r hi oe d out. Brazilian commercial corn is extremely heter c oo gn et na ei on us s ,m any defective plants and shows many undesirable traits. A vigo selection was carried out, combined with eolfing cur t ii no gn s %, £a en wd finally followed by sib and strain crossing. The re fa sr u lo tb ­t a ti hn ed in small plots se.m satisfactory and better tha b ny m ta hs os s es e ol oe tc at ion without controlled pollination, though inferior, especi. / in homogeneity, to authentic hybrid corn. F.G. Brieger and E.A. Graner E ­ Late Sugary Strains: Some good sugary strains, very late for Connecticut, were given to us by Dr. W. R. Singxet i on n o au nr a d ae rp ea r nt °m *e nt. T ”hey include a strain segregating for­a ^ r y laoe th ya pt does not flower there but is expected to flowe:' here, .ne p the field are now 40 days old. E. A. Graner ^ 2. Experiments about the Origin of Corn A ­ Native Indian Corn: We were able to obtain through the help of Brazilian colleagues, of Dr. Cardenas of Cochabamba a a nu dth e on ft i Ec r . "wild Indian" corn. The Bolivia corn from Cochabamba w ge rl el w a vt e rt yh e low altitude of Piracicaba, flowered generally well, but 494 roduced very poor ears. Material from the lowlands of Mato Grosse (Brazil), from Paraguay and the Bolivian Chaco is much more satisfactory. But in nearly all cases it was rather difficult to maintain the strains, since they degenerate very rapidly with more or less close inbreeding. The following material has been studied genetically. "Acre” from the territory of Acre (Brazil). The plants are very tall without tillers, ears long and slender with 8 rows, grains large, round and soft, exhibiting the following colors: dominant purple (ACR Pr), red (pr pr) or recessive colorless (probably rr), brown aleurone (lost), yellow or white endosperm. "Chavantes" (from the State of Mato Grosso, Brazil). Very tall plants, segregating seal­dwarf, ears big and heavy, 12 or more rows, grains large, soft, white or sometimes tinged, purple (I’r), red (pr pr) or light pink (pericarp?). The constitution of these grains is probably AA CiCi RR as shown by the following test cross with C sh: (F2): : C1 ­ Sh : ­ sh sh CC Sh ­ : CC sh sh : Total obs. : 861 : 34 61 : 187 : 1.143 The dominant inhibitor is not completely dominant and varying percentages of the kernels with the constitution C1­Sh­ are not white, but very pale purple and red. It seems as a whole that the Indians selected^ modifiers which reduce all possible color in the kernels as much as possible. White endosperm is only incompletely recessive to yellow and there is present some kind of pericarp color which however becomes clearly visible only after outcrossing. "Diamantino" (from Mato Grosso, Brazil). We received three lots of seeds. In all of them the ears originally were heavy and many rowed. The color of grains varied. Diamantino I. had deep red pericarp (P) segregating normally after crossing. Diamantino II. had dirty brownish­orange kernels, due to orange, white or colorless pericarp on yellow­orange endosperm and sometimes yellow­brown aleurone. The segregation for pericarp color was interesting in so far as its existence could be verified only in some years, and in one year onl> classification between orange and colorless pericarp was very easy. In this year orange pericarp was in some instances so intense as to give a aright red color. Diamantino III, contained colored and colorless aleurone over orange endosperm sometimes covered by orange pericarp (white cob). Absence of aleurone color may be due either to a dominant or recessive inhibitor. The former is certainly an allele to the C factor as shown by the linkage test with CC sh sh But there are a large number of modifiers acting and disturbing the ratios. The ears collected after selfing fell into two groups. In the first there was an excess of colorless­shrunken grains combined with a deficiency of the colored­shrunken grains. In the other group of ears, besides this deviation, 495 ,e appeared a deficiency in the number of the normal grains and a corres­ ponding excess is the colored­shrunken grains. C1 ­ Sh 3h sh CC­sh CC sh sh Total 250 1st group 1.270 H 6 52 232 1.700 A25 1st group 771 99 201 212 1.283 328 Plant color in most strains of all three forms of native corn, «cre Chavantes and Diamantino, is either dilute purple or dilute sun ree. R„t the culm is very frequently heavily colored, and this color seem.,, luast partially, independent from A­B­Pl mechanisms. In the shucks various colors were observed which may be either nSun red”, deep purple, dilute purple, red and reddish­brown. Finally, the glumes and the whole base of the grains may be deep or light purple or red, independent from cob color. Apparently someh co owlo r t ns "depends upon the same factors as the color of the shucks. So far the existence of these different colors in vegetative organs has been registered; but it has not yet been possible, owing to lacx oi time, to start on a detailed genetic analysis. If we take all characters into consideration, it seems that the indigenous strains from Mato Grosso together with the material collected C ut yl er in Paraguay and the Bolivian lowlands form a natural group. Sunils traits may be found also in local forms, cultivated in d o Paulo. In of them there appears, with more or less frequency, all or some oi the following characters. Slender and long ears with flexible rachis. Grains half covered by their glumes. Kernels more or less round or pointed, containing s ta sr oc xh . Anthocyanin generally absent in the aleurone owing to the pre o sf e ni cn eh ibitors at the C­locus. On the other side there !s a^tendency for a ­p pearance of brownish­orange colors, in the aleurone, endosperm, ­ P Three characters seem to me especially important: the brownish­ orange color of the kernels which may be considered a a s n aa nt ural "wild” co pl no tr, thT slender and flexible_racnig and the developm o ef n tl arge glumes which may be taken as a change in the direction of pod Th ce oi rr .w idespread occurrence can hardly be considered as a coincidence, in view of the old hypothesis, recently taken up again by Mangelsdorf R e ae nv es, that pod corn is the most primitive of all the different types m a oi fz e and that the lowlands on both sides of the Rio Paraguay, i.e t .r ,i a tn hg el e formed by lower Bolivia, western Mato Grosso and Paraguay, may be the geographic centre of the origin of maize. On the cont o rb as re yr ,v ations 1 , very briefly reported above, support strongly this hypothesis. F. G. Brieger B ­ Pod corn: Has been obtained from two sources. "S£o Paulo Pod" and "Bolivia Pod”. The latter was sent to us by Dr. Cardenas and later Dr 7. Cutler. The other type came from one ear left casually in our eP^r nen"' 496 ,indent and about which we know only th i a ti o itf r co am m ea n f ri on mh abita Ct ae rd l oa sn ,d cultivated reg T iop n t ona lf y a an bd wh oe ur te Jw 0e 0 c Ka mn .n o ft i oe xpect to fin f d° "nati vf ea c Int do ir ans ", coe rx nc .e pt Ino f a lc lo urse being pod corn, it correspon B dr sa zi tl oi a tn h ecorn of the region. The studies of Bolivian pod corn are still in t h h» ev e bm ee gt i na ng ia ni gn at nh de wd ei fficulties menti R on nU ev di a an b oh vi eg ,h l ta hn ad ts cg or ro nw s f rw oe ml l H, 1®but hardly prod ? uc^ esVw e e ac ra s n is na y o uo rn l ay l tiso t udfa er . that it contains a dominant Tu gene. Paulo pod corn is also due to a dominan t tr a gn es nm ei t wt he id c ht h ir so u ng oh r mt ah le l yf emale while there ^ i­ sp o al l se an r ot nu gb e ss e. l ecA tt i ot nh e a gm uo is t, half of them may eventually function, but generally less* The original ear was large and well filled h a wr id t hr a ac hi ss l. e ndeT rh e bus te e vd es ryc overed by large glu ? meqs s ,p o wi en rt ee d s ma an ld l s at no do d m oa rt r oth re end of a l l oe nn gg t ph ea ds i cet lh ,e os fe ed a boi uts te l tf h. e sT ah me e tassels of th g e^ o fwn i rh sa td td ur no io cp ai tn eg gb er na en rc ah te is, o nw ^i th nearly normal or somewhat enlarge an dd go lc uc ma sionally some silks. Owing to the degeneration after inbreeding, t to h eb e o ro iu gt ic nr ao ls se ld i, n e a hn ad d native Indian corn was used for this purpose. The Tu ears in later generations varied very much, b te hi en g e xs ti rl ek ml ee ss s sterile ears, sterile ea o rr sd i wn ia try h fertile Tu ears and, final c lo yv ,e r fe ed r^ tb iy l et h ee ai rr s g wl iu nm ne s. T *h e rachis T nremained e ax lt wr ae ym se ly t hl ia nr g ae n df e rr it gi ^l .e ea I rs the circumfe k re er nn ce el s n ed ci ef sf se ar re yd fv oe rr y t hm eu ch from the circumference ca os fe ̂s th e r ar ca hc ih si .s s Ip nl it open lengthw t io sg ee ,t h te hr e i rn o wf so urs, ^ awi it nh „ one group ^ o bf e rt w wo a sremaining when the total nun not a multiple of 4* a„ rsfc. *srr. ss“is he sav iil sy bearded. «In «some cases it seems that each spikelet l e ca ost n to an me e female or perfect flower. These hermaphroditic tassel b se gi wn en ri en g v. e ryW i lt ah r get he a nd Setting of s ^eeds they became u p vs ee rt y s ho em ae vw yh a at n dt h te e nb da el da n tc oe of the plants. But one n u t a nt oa ts s fe ol r gw ei tt h t ha total length of Jfl c T mh . er ie s s se me am ls l t oo n o ac cur in °t fhe °se r n o t ^ d ue n r of s i cb axe ­t ew e pe ln a nt ta ss s ae ni mb cas re and ear, bu .t j t *he c i v. n eor tr ee rs np oo dn ed si n ­g ­ l ie nav e ss h os rh to w a nt dr a tn hs ef ormations in the direction o. shucks However the most interesting transformations are t o ^ f o u n d s t iru nc tt hu ere of the spikel m ea tl se . fl To hw ee r os r na ir re k .rs yu b ss pt ii t eu ted, in di lf af re gr ee n var o tt h t i a es ts ye l os fer comb ,i n ba yt i ao n ls a: r ge1 vm .a rl ie o Jr sterile and 1 female or perfect flows., 497 female flowers, 1 female and one perfect flower. But the most outstanding ̂ es occurred in the spikolet of one tassel where one male flower was f flowed by up to four female flowers. At the same time a tendency appeared for splitting the ends of the individual silks into two arms, often of unequal size. Thus the Tu gene causes the appearance of characters long lost in the group of the Maydeae and the related Andropogoneae: many flowered spikelets. The observations, reported above were mainly made on plants heterozygous for Tu. Owing to the elimination of the Tu pollen tubes, the number of Tu­Tu homozygotes must naturally be small. The phenotype of the homozygotes registered with certainty so far does not exceed the limits of variation of heterozygotes. If we leave aside the effect of provoking^the excessive development of glumes in the ear, then we may consider as next important feature in "Sao Paulo Pod” corn the accentuation of female tendencies in the tassel and the reappearance of characters lost in the phylogeny of many grasses: the re­establishment of hermaphroditism in individual flowers and the occurrence of spikelets with more than two flowers. But this does not necessarily mean that the immediate wild ancestors had those characteristics ana may thus have belonged to another group of grasses, not the Maydeae or Andropogoneae. We may have to deal with still older characteristics o primitive grasses. Recently Mungelsdorf and Reeves have modified the theory that pod corn with its covered grains in the ears is an approximation to the wild ancestor of maize, assuming that this ancestor was a plant without the lateral ears, but with covered seeds in the tassel. If this would be true, we should expect that the lateral branches, instead of having still normal, but sterile ears, should also terminate in some sort of bearded tassel. Selection in this direction has been started, but in order to obtain positive results it seemed necessary to substitute the modifiers of cultivated corn by modifiers of a "wild” form. This seemed possible only by crossing pod corn to teosinte. F. G. Brieger C ­ Hybrids between teosinte and "Sao Paulo Corn” ­ Hybrids were produced between teosinte and heterozygous ”S~o Paulo Pod” corn, consisting of tunicate and non­tunicate plants. The tu plants in F]_ corresponded as a whole with the descriptions given by other authors, and we shall withhold discussion until the analysis of F2 and backcrosses, now under way, are terminated. The Fp tunicate plants, however, showed many unexpected character­ istics, some of which only will be mentioned here: The Tu effect on the tassel was completely recessive­hypostatic and it was impossible to classify the Fj_ plants as in the original Bao Pc~ulo Pod", according to the transformation of the tassel. Thus the tassels 0 Tu plants and their normal tu sisters were identical. The ears, however, were very different in Tu and tu hybrids. In the latter the rows were mainly single, or when the paired row was not suppressed, they contained femele spikelets only. Two paired rows appeared generally in 498 ,,p tu plants, one being an ordinary female spikelet, with one sterile ana female flower, while the other spikelet became pedicelled and contained two male flowers. Furthermore, there was a pronounced tendency to produce not only 2 double rows, but 3 or even 4* The scales formed by the rachis and which cover more or less the grains in teosinte or in tu Fx plants, were smaller and soft m Tu plants while the glumes became pointed. The rachis and glumes of the tu hybrids are extremely horny, and it was very hard work to shell the seeds. On the other side, the racnis in Tu F­i plants is extremely brittle and it was nearly impossible to harvest complete mature ears, since they fell apart immediately after removing the shucks. Thus the Tu gene has a very different phenotypic effect in pure corn and in teosinte­corn hybrids. In the former we observe a pronounced tendency to introduce femaleness into the tassel, while in the latter maleness appears in the ears, or better on the lateral branches. A selection experiment is under way with the end of fixing this condition, jus was possible to fix more or less the bearded tassel. The fact that the Tu­gene acts in nearly opposite directions according to the modifier complex present, should warn us not to draw premature conclusions on gene action. The appearance of covere. erne is a universal effect of the Tu gene, while everything else depends upon th modifier back­ground. The Tu Fx plants described above seem to me much more likely to be a replica of an ancestral wild grass than the Tu .ora plants with bearded tassel, especially considering the following points: a) the rachis is extremely brittle: b) the lateral branches are not suppressed, but g»ow perfectly normally, producing terminal y a >aoSt ear, and laterally still more branches or higher order with a varying number of additional ears: c) instead of a reduced or sterile ear, wc encounter ears, where one female spikelet tends to be as^ocia e wi male spikelet. While I think that the general structure of the Pod-Corn-Teosinte hybrid is a more likely reproduction of a hypothetic wild ancestor o c0™ as compared with the bearded Pod Corn, I do not believe that this ancestor actually was a hybrid. There have been proposed several hypotheses to explain the morpho­ logical nature of the many ranked corn ear. Hero again our Pod­Corn­ Teosinte hybrids offer valuable material since the Paired spikelets are often different, one being sessile and the other pedicelled. In two­ranked ears or in tassel branches we find in general a very regular situation. Both sessile spikelets are localized near the ventral side of each a veo and the pedicelled spikelets on the dorsal side. But this symmetry seems to be the consequence of some physiological conditions. In many ra e e I did not find a regular position of two spikelets of the alvecii ox eac . double row. The sessile spikelet may be on the left or on the right si of the pedicelled spikelet. Other interesting observations could be made in some of the F2 plants. In several instances, an alveolus contained one sessile spikelet 499 A one "branch" which carried one spikelet more or less in the middle and Mother at the end. If the pedicel was shortened three spikelets appeared ‘ together in the alveolus. In one instance an alveolus contained 4 spikelets which probably were derived from two reduced branches with 2 spikelets each. Finally all observations seem to indicate that the only constant orientation of the alveolus may be the longitudinal row, sometimes obscured bv a twisting of the rachis, or altered by the intercalation of new double roWs. The appearance of 3 rows of alveoli, the transition of this arrange­ ment 'in to one with either 2, by suppression, or of 4 double rows, by intercalation, is quite frequent. The alveoli may be all at different levels, or at the same level. Neither yoking nor a spiral arrangement could be observed with any regularity. Thus the Tu Fl and plants offer very interesting material, especially when studied at flowering time and not when their ears have become hard and mature. There cannot be any doubt that this material will finally permit a critical discussion of the hypothesis of the nature of the ear and tho formulation of a new, combined theory, containing to some extent elements of older views. But the final discussion will be delayed until the analysis of the mature and backcross ears is completed. F. G. Brieger D ­ A histological study was carried out on several strains of native and cultivated corn and of a North­Amerlean pop corn. The structure of the latter was identical with that described by Randolph. In corn of the Paraguay river group, as defined above, the following structural elements were; the most striking: The spikelets appear to have a pronounced pedicel. At the lower base of the pedicel and at its sides a scaly outgrowth of the rachis appears which thus surrounds the alveolus on three sides, and which corresponds to the cover of tho kernels in Tripsacum ana Euchlaena. The spikelets of Paraguayan corn which when mature had the kernels half covered by glumes, had at flowering time the same structure as "S^o Paulo Pod" corn with well developed glumes. F. G. Brieger and H. C. Cutler E. Tripsacun australis: Seeds and rootstocks of this species collected by Cutler were planted. Only two seedlings germinated and grew slowly. One of the rootstocks gave a large plant which started to flower in November and is still in bloom. The second is starting now in January. F, G, Brieger and H. C. Cutler It has 13 normal pairs at meiosis. E. A. Graner 500 3. Genetics of Aleurone Color It is generally accepted that the presence of anthocyanin in the niourone is duo to the presence of certain alleles of the locus: _ A2 ­ C ­ R. But, as I have pointed out elsewhere, the action of the nes at these four main loci is conditioned by the coordinate action of the modifier complex. This could be shown by several selection experiments. A line of red brittle, originally from Cornell, served to demon­ q+rate that by selection, completely colorless ears may bo obtained. j.n the original line occasionally a colorless grain occurred, and it was possible, hv selection for higher number of colorless grains and for paler color of the"still colored ones, to extract a line which was completely colorless.^ Fnen backcrossing to colored linos, no clear segregation could be obtaine . Some of the brittle kernels of the original line appeared to be nearly black, which was attributed to the effect of an intensifier absolutely linked with bt, or to the action of the respective bt allele itself. All selection against this factor was useless. In the extracted colorless lines there still appeared a segregation for a recessive gene, producing deep black brittle kernels. Thus a gone which in the original material was only an intensifier and as such difficult to analyze and classify, became m the extracted lines a recessive determiner of anthocyanin color. Since no crossing over has been observed so far, we suppose­ that the original line contained two alleles of bt: the­ ordinary bt without effect on aleurone color and the new allele btr which causes a deep black color and which is epistatic, when homozygous, over the modifier complex w h ich dominates otherwise the action of ACR. In formulas, we represent the situation: bt bt A1 A2 C R + original modifier ­ purple (Pr) group or red (pr pr) btr btr A1 A2 C R + 1 ! tl 3 black (Pr or group pr pr) bt bt A1 A2 C R + extracted modifier group = colorless btr btr A1 A2 C R « n = black The opposite result was obtained in "Chavantes" which as mentioned above has probably the constitution: A1 A2 C1 R where Ci represents^a dominant inhibitor at the C locus. Pale purple (Pr) or red (pr pr) kernels occurred in the original material and, by selection, ears could first be extracted which segregated colored kernels in various proportions until finally fully colored ears appeared. A corresponding situation was found in "Diamantino III" where a sharp segregation occurred for black or orange kernels. But black grains gave ears which segregated for a recessive orange while orange kernels gave ears segregating for a recessive black. The classification was gener^ll> 501 us. ',v h­ut the ratio colored : colorless did not correspond to any standard Mendelian ratio. It is remarkable that some lines segregate normally in some crosses, and show the modifier effect in others. Thus a "Golden Bantam", when crossed to a cc sh sh ­ test line was shown to be AA CC rr giving a 9:7 ratio in F2, but crossed with the rod­ brittle line a mono­factorial^ segregation was obtained only in part of the offspring and a selection foi both low and high ratios of colorless was successfully carried out. These results may be summarized in the following form: There are some lines where the modifier complex is well established and in balance with the determiners, not interfering with their action. Such lines give sharp segregations with normal Mendelian ratios. Other lines have an unbalanced modifier complex and here selection experiments may give positive results. Thus it was possible to shift the color from red to white in the red­brittle line and from white to purple or red in "Chavantes". The experiments are being continued and it is hoped that eventually a more complete understanding of the physiological action and interaction of determiners and modifiers may be obtained. The selection lino of "Chavantes" was very instructive in showing that we must distinguish between modifiers which ace as plant characters and others which are evidently only aleurone characters. It may at first seem strange that aleurone characters may be dependent upon genes of the mother­ plant, and not only upon their own genes. However the effect of plant genes upon the endosperm seems to be quite general. The difference between flint and dent, between round or pointed kernel, to a large extent the difference between flint and floury, are inherited as a plant character. Nov/, if sporophytic genes control the type and distribution of stcrch in the kernel, there is no reason why one should not accept the same for the formation of anthocyanin. F.G. Brieger and George O ’Neill Addison U. Yellow­orange Endosperm Studies on the genetics of the yellow­orange endosperm started at Piracicaba, Brazil, (1937), were continued at oolumoia, Missouri, xn I9k*­> through the help of a fellowship from the Guggenheim Foundation. A deep orange endosperm from Brazil (commercial strain) was used and crossed with several white endosperm strains. These crosses gave only segregation for one pair of factors. Some were continued un^il F^ ana the white endosperm strains checked proved to be yl yl Y3 Y3* Crosses with some white endosperm testers segregated again 3 colored : 1 colorless ana showed independent assortment for chromosome 2 (lg 1), U (su l) and 9 (df 3) indicating that the yellow gene segregating should be the Yl in chromosome 6. The same deep orange strain when crossed with a tester received from Dr. Jose Ma. Andres, Argentine and called A­(alal B­) (Pl­yl yl) showed a clear segregation of 9 orange : 3 yellow : U white. The numbers of 3 ears 502 f\ken at random are the following: No. of the ear Orange Yollow White Total 40 ­ 12D ± 1942 156 42 61 259 31 ­ 12D ± 1942 154 56 62 272 x 17 12D 1942 137 43 49 229 Total 447 141 172 760 Linkage was found with the P_1 gene (repulsion phase) and all yellow seeds were albesoents al, the white ones segregating 3 Al. 1^1. As the al gene is probably the same as yl or very closely linked to it, it could be said that the deep orange Brazilian strain has both L L and YJ_. The linkage with chromosome 2 in this cross was also shown by the segregation of B. The al strain when crossed with lgl showed absolute linkage (repulsion phase). By the segregation of A it was found that chromosome 3 was not involved. The 9 : 3 : 4 instead of a 9 : 7 ratio as found by Perry and Sprague (1936) seems to indicate the existence of another complementary gene, probably to Yl, which probably is a plant character, since its segregation was not shown in the seeds. The F2 plants are now growing, but have not flowered to this moment. The­ Fp of the same cross was used at Columbia, Missouri, for crossing with other Y­testers, received from Br. H. S. Perry and the plants are growing at Piracicaba. Some unexpected ratios, were found in these crosses and will bo checked in the next generation. The deep orange Brazilian strain planted at Columbia did not flower there. So this strain could not be crossed with other testers. However, it was possible to use an Argentine strain called Colorado Casilda and belonging to Dr. L. J. Shadier1s collection. This strain has practically the same color as that of the Brazilian one and its name indicates the same variety used by Dr. J. Ma. Andres in Argentine (1939) nnd giving results similar to those reported here. This Argentine variety will be now crossed to the orange Brazilian strain, but to save time, it has been crossed to testers for all chromosomes. The collection of testers used was prepared at Columbia, Missouri, and includes material from Cornell (Coop) and from other corn geneticists of the States. These crosses are being checked now at Piracicaba, Brazil, where the plants are just flowering, but the situation is rather complicated sinco we d; not knew the background of the testers used with respect to the Y genes. Also, it should not be expected that we have to de^l with only one sporophytic gene but several may be acting as modifiers, giving the shades found in different yellow­orange endosperm strains. Other strains of yellow­orange corn ol different origin are also being tested. Some pop­corn ears from Brazilian material showed segregation approximately of 3 white : 1 yellow­orange, and we don't know if we have here to deal with a new Y factor or only with an inhibitor of the known Y genes. 503 Seeds f 14 and It received from Dr. W. K. Singleton proved . t. o. bea - n. rrs*.;”?;!-1 S0«”; 5 «.o t - E. A. Greiner 5. follow 'Aleurone In tho crosses with (loop orange endosperm of Brazilian .. . g ra„ i„„ n= s a< n­ d, „rre'Ption of a yellow­aleurono gene was found. l Tl hh o i in no ten re ac tI if ov nSry variable and in some back­grounds difficult to cl ° aL sso i fyt .h t dosage in the endosperm makes tho problem difficult s f i, nm cd e t ih ta t w a" ss imple" is not different from "nullplcx" white seeds when y te h1 el ow­alourono strain is used as male parent. Until now i is pos­i « S s thH o ! ^ . t “ l93t : * - ^ o w been sa segiregiat“ion of 12 orange : 3 yellow­aleurone : 1 white or 15 cola, colorless * 6. Linkage Tests A small number of linkage testers, of Cornell o r i g i n , was brought over from England and some others from Cornell. It was soon t wt ia dse e nN *o rth­American strains are difficult to grow in Brasil. t o * rather * 1s 1mall and weak, so that it was nec p er se sp aa rr ye d t ob e pd ls a. n t T th he ey m s ie nen to grow and produce reasonably well when pLnt d in the first part of summer, that is, during, the period whent th he e d 1a ­y n gi ts h s ot fi ll increasing. For crossm. purposes, it was alw y t so am aa vk ie s several successive plantings, with the hope that sometimes he flowering period of tho strains to bo crossod may coincide. Crosses between those imported lines and local linos, such as Cateto, or with native Indian corn (Bianantino III) Chavantes^ et­.) c a .r ri ­ed out and the extracts from those hybrids, arc promism. . F. G. Briefer A good collection of recessive and dominant jenes in all chrom w oa ss o mo er ^g anized at Columbia, Missouri with material received from Corn ( eCo lo lp ^) and from Drs. L. J. Stndler, H. Human, L. F. Randolph C ,. R H. . SB .ur n Ph ea rm r, y ,R. A. Brink, W. R. Singleton and others. The g pr lo ­w ni tn sg aa rt e P ni or wa cicaba, Brazil, and they are growing very reasonab s lo yme . ex Ap fe tr ei re nce we think it possible to grow in Brazil some s t or fa i ^ns A min . ith lo e am no nths of November to January, when we ha the ma l xi i m­h ut m oa fb out 15 h >ur* a day. Plants sown m December are flo d wa eyŝ nnas b' 1 i c no m 5p Ua red" with the same strains in Columbia, Missouri, flowering in 55 days. 504 The problem of genetical tests for Brazil consists in the transference of the genes to lute Brazilian strains, but we don't think this solution satisfactory since some segregating plants will be so late as .0 make our work difficult. The principal genes in all chromosomes were crossed in Columbia with an Argentine strain and the hybrids look good for our conditions. We think it will be possible to isolate the segregating genes in this back ground and in plants not too late and promising for Piracicaba. Deficiency testers produced by X­ray in chromosomes 3, 4> 0° ’ ^ „nd 10 were introduced into our collection from material of Dr. L. J., Stabler. The deficiency in chromosome 5 itf linked with Pr, m chromosome 6 wi ond in chromosome 9 with I. The deficiencies in chromosome 3, 4, and 10 were crossed respectively with Eg, Tu and 0£ in order to get these dominant genes linked with them. Translocation­B testers from Ur. H. Roman for chromosomes 1, U, and 7 were also brought to Brazil. The Tb­A test has boon useful in chocking the su gene in many of our experiments. A collection of trisomics from Cornell will be crossed with the respective rocessivoo in order to facilitate its conservation without the necessity of cytological work. The use of all these tests was started at Columbia, Missouri, in checking new mutants and will be continued at Piracicaba, Brazil. E. A. Graner 7. Brazilian Story Treated by Ultra­violet A Brazilian hybrid corn that flowered normally at Columbia, Missouri, was treated by ultra­viaLet. Pollen grains were treated and used lor pollinating untreated plants. The oOO seeds collected from 3 oovm in Brazil, giving good germination (8($). The plants are growing and aaj mutants in this back­ground, proper for Piracicaba, will be used as testers after their localization in their respective chromosomes. E. A. Graner 505 / November 22, 1943 To Maize Geneticists: In the Indian Journal of Genetics and Plant Breeding (2: 184­186. 1942) is a review by B. S. Kadam entitled: Maize Genetic Cooperation News Letter No. 16. 1942. The review of this News Letter seems to me to have been fairly well done. The point at issue is that no request Was made for permission to publish such a review. News Letter No. 16 included this statement: ’’The presentation of data in these news letters is no , to be regarded as constituting publication. These data should not, therefore, be used in published papers without the consent of the authors.” The above statement was quoted in connection with the review and no data were published in the review. It includes only summary state­ ments about the reports contained in the News Letter. It is evident, therefore, that Kadam obeyed the letter of the quoted injunction. I cannot, therefore, do what I was at first inclined to do, namely, to notify him that hie name would bo removed from our mailing list. We have for years sent the News Letter on request to numerous workers in other fields of genetics. The principal objection that I see to such use as Kadam has mado of these Letters is the con_usion that may come from it. The Letters are not available in the libraries of the world. Such reviews as that puollshed py Kadam are apt to bring numerous requests for the originals. Perhaps Cook was not iar wrong in his objection to such ”unpublished publications". The question that I wish you would answer for me is: should we send the News Letters onl; to workers in maize genetics? Please give me your opinion. Sincerely, RAE:P E. A. Emerson This is being sent to ­ E. G. Anderson Barbara McClintock R. A. Brink P. C. Manfoelsdorf C. H. Burnham L. F. Randolph H. K. Hayes M. M. Rhoades M. T. Jenkins G. F. Sprague D. F. Jones L. J. Stadler E. W. Lindstrom 506 MAIZE GENETICS COOPERATION NEWS LETTER 18 January 31, 1944 The data presented here are not to be used in publications without the consent of the authors. Department of Plant Breeding Cornell University Ithaca, N. Y. 507 CONTENTS Page I. Important Notice ................................... ^ II. Foreword ........................................... ^ III- Reports from Cooperators .......................... Bureau of Plant Industry Station ................. 2 Bureau of Plant Industry and Purdue University ... 2 Carnegie Institution of Washington, New fork City 2U Columbia University ............................. Connecticut Agricultural Experiment Station ...... U Cornell University .............................. 7 Cornell University '’ '-1 reorgia University...... . 9 Duke University.................................. 26 Florida University............. ................. Iowa State College ......................... ^5 Minnesota University.................... 15 Missouri University ........................ ■»*••• ^ Venezuela Institute Experimental de Agriculture. y Zootecnia .................... 27 IV. Maize Publications..... ..........«t................ ^9 7 . Seed Stocks Propagated in 1 9 k 3..... *.............. ^2 508 I. IMPORTANT NOTICE Tlie Maize Genetic Cooperation News Letters carry a statement to the effect that the presentation of data in them is not regarded as constituting publication and that no such data are to bemused in _ p ublications without the consent of the authors. A foreign geneticis ;nd plant breeder, not working with maize, has published a N e rw es v iew of^Letter 16, 19-42. He-was aware of the injunction and quoted it m th e review. He included none of the data but did include the.pernaps tentative conclusions drawn from the data by the authors, “bile, therefore, he obeyed the letter of the injunction, it can hardly be maintained that he accepted the spirit of the ride. I conferred by letter with a number of the more active cooperators in this country. Replies ranged from one extreme to tho other. Some thought that even such publication as had occurred might be aisasterous and that, in the future, the News Letter should be sent only to those cooperators who contributed material. Others saw little dangei, at stage of our work, from such a review as had be^n published and sugg n eo stc eh da nge other than a rewording of the injunction. Most replies suggested a middle course between these extremes. I am, therefore, adopting e following procedure. This News Letter is being sent to thouo 0 ^rf' n) c *o operating or who have furnished material in the not too distant pa F -u rt •_h er copies will be held here to be sent on request to other geneticis o sr breeders. I shall have to depend on my own judgment (good or sad; m determining whether particular requests shall be honored. R. A. Emerson II. FOREWORD (Swan Song) I have been connected more or less intimately with Maize Genetic Cooperation from its beginning. Some years i have had to devote con­ siderable time to it and other years almost none. On the wnole 1 ..eô that I have probably done less than I should and certainly less than a m cr ^e dited with having done. I am now an "emeritus" and rather enj I o ya m na ,n xious to complete (before my number comes up) certain maize gene,i<- problems that have been underway for a long time and which will requir y ee t further year3 of work. I am willing to admit no more than the - n 1o t amg rowing younger as the years ~o by. Any way I feel that, whether o r w e.p ,o orly, I have about done ny stint and that some one else should so a os ns ume responsibility for this cooperative effort. An appropriate time for a change is now when our most recent grant from the Rockefeller Foundation is to be closed out. I shall, of course, retain an interest in this undertaking. If no other prior arrangement is made, I shall probably find myself planting certain genetic stocks again next spring and at polli wo nn ad te ir o n time shall why I haven’t yet learned to limit my planting to what I can take care of. 509 During the past year, many genetic stocks that were most in need of 1 cnishmunt wore grown and pollinated by Dr. if. J • Murray and Miss reP'dind Morris. Miss Morris has grown in the greenhouse many cultures In'-' seedling characters. When resort must be had to ears from P rialbplants of segregating cultures, it is important to determine n°.ry, 0f the normals are heterozygous for the characters in question. Iv Murray also spent much time in a study of the stocks on hand and o • available records and succeeded in bringing at least some measure o ordor into the rather chaotic situation that I had allowed to develop. R. A. Emerson III. REPORTS FROM COflPERATORS Bureau of Plant Industry Station, Beltsville, Maryland A cross involving opaque-2 made in 194-2 and selfed in 194-3 segregate for an endosperm-color gene very closely linked with opaque. The, gene has not been identified but since no gene aflecting endosperm color ■previously has been reported in this region of Chromosome 7, tue pre- liminary data are presented in the following table: Flinty Opaque-2 Dark Lemon Dark Lemon Yellow Yellow Yellow Yellow Total 2337 21 42 752 3152 The data are not too satisfactory as considerable diffaculty experienced in classifying the opaque seeds for color. They indicate about 2 percent crossing over between the two loci. No symbol iŝ suggested for the endosperm-color gene as too little information is available on it at the present time. Merle T. Jenkins Bureau of Plant Industry and Purdue University- Department of Botany, Lafayette, Indiana In 1941 one plant from a very uniform appearing ear-row Ox inbred jjjyg produced a solf-pollinatcd ear segregating approximately 3tl for^ salmon yellow and ivory colored kernels. When planted in a germinating bed the yellow seeds produced all green seedlings and the white seeds produced only albinos. In 1942 a row was grown from the yellow segregates and each plant soIf-pollinated. Of the 20 ears produced, 7 were homozygous yellow and 13 were segregating for yellow and white. Seedlings grown from those segregating ears gave the following totals: 510 : Seeds : Seedlings :planted: green : white. Yellow seeds: 3910 : 3030 : H White soeds : 1101 : 11 : 735 mpn of the 11 exceptional green seedlings from white seeds were success T iiv transplanted and grown to maturity. Because of unfavorable e dition" only five of"the attempted self-pollinations were succeSaful , , + 1n GV.ry case both yellow and white kernels were produced ^ .o ar Io t proLblo that a single gone with a dual effect was^involved in tho original mutation, and that thu aberrant seedling JT?es *GI'' hetero-fertilization. A. M. Brunson Columbia University, Department of Botany, New ’fork City 1, In a stock homozygous for the dominant B|r-1 allele^ rt frn’i Bt to btm This new allele :ls unstable and mutates nitn °°high frequency to ft- Seeds of JrJ? bt31 constitution are mosaics o n fo rmal and brittle tissue. Germinal mutations are numerous -- 7.5, of nn .'Gifod btra btm plants are reverse mutation^. Iho Bt, allele obLinodly rtvorso i t l o / a r . stable. The bt» allolo occasionally nutates t / a stable bt allele which is indistinguishable from the old _ -Hole, ilhilo genic modifiers influencing the mutability of the allele exist it is evident that this allele is intrinsically unstable, and this case is not similar to the a Dt situation. 2. Goldschmidt in the Proc. Nat. Acad. Eci. 1943 reports a situation in Drosophila molanogastcr whore the interaction of alleles a At t rf two ,runt loci -iver, results somewhat similar to those repor ^ tt eda b fi of rg enos. He suggests that the idea of unstable genes bo abanuoned, end that the so-called unstable genes of Drosophila and maize can accounted for in terms of factor interaction, epistasis, a n d condi ^ti ons. He specifically cites the a-fitcase in maize. ^Aco^r-^g his interpretation the apparent mutations ox a to a , - - indueeu by the Dt gene, are in reality cases where a new Dt allele (which vdll be represented Dt*) produces the color ascribed to too e l £l rle. He also states that no published data exist which negata hie interpretation. Actually two decisive experiments have been published which establish the correctness of the mutationhypothesis, (l) T h e± allelos obtained by mutation fr^i recessive a show t 1 he expected with 'ones in chromosome 3. On Goldschmidt's scheme the color-produ n cl il nel go would bo in chromosome 9 since Dt is in that chromoso , m e, . . U) a mutation of« V.ncn a +t o Aa ucmcnurrqs iinn aa c ' o . 'oi n .s ot n l of- f a Dt Dt constitution tht,itution of that coll follow ri wn ig d sm cu ht ma it di to 1 n s is A a Dt Dt. On Goldsct scheme it should be a a Dt^ Bt.* M. M. Bhoados 3. The vascular bundles of corn leaves are surrounded by a single layer of bundle sheath cells possessing plastids differing m size at shape from the chloroplasts of the mosophyll cells, iho plastid,, of 511 .oDhvll cells contain no starch; the sugars they produce ar Tv e moved ib nu tn od le sheath cells and there transformed to starch, starch in t hL ̂si^ly accumulates in the bundle sheath p 5 lastids in the h d! ayn ;i g dh ut r it nh ge starch is changed to soluble carbohydrates and tran * sl ocatioT nh e plastids of the bundle sheath cells are usually devoid o ° f+ rch'by morning. These plastids contain a green pigment, St pf re sumw ai b? ly but Ire of a lighter green color than are the chloroplast t sh e^mesophy11. Photosynthesis may occur in the bundle sheath f P" l, a^ r idt sh .e green color of the bundle sheath plastid is similar to I^rd Te tl hl as t of the stomata. Sayre found that the guard cells of Kumex contained a light green pigment which was not chl T ot rh opo h ya lb lo .v e If acts it will be of interest to ascertain whether or not the p eon pigment in the bundle sheath plastids is chlorophyll. Each of the bundle sheath plastids contains numerous, discrete regions, which may be likened to pyrenoids, in which the d e sp to asi rt ce hd . s It is surprising that the structure and functions^ the u sn eu sual plastids have not been adequately described._ Kiossel a tn ad' c hc i Ute d w i n Weathorwax 1923) noted their abnormal size and shape m e bn ut ti o dn i dt heir function in starch synthesis. He believed thes^pla.tid, tad different shapes in fixed from those in living mater o ib as er . ved, h ,owever, the same variation in size and shape in both fixed and living cells. »* 01__ r.nrJ fllM d n s C arvalh o Connecticut Agricultural Experiment Station New Haven, Connecticut 1. Long-inbred lines of corn infrequently show heritable variations. A se-rch among all the inbred material available over a period years tas revLled deviating lines that differ from the lsome distinct morphological or physiological character. Pre v Oa Tr ia bt li yo ns are single point mutations, although it 1 E difficultto separate primary changes from delayed segrega f ta ir o nf so .und appear to bo degenerative changes, reducing the ability of m ti hn et to grow and to reproduce itself. They include delayed flower l ie na gf , blotching, narrow leaf, reduced plant size at maturity, .rook . . . end chlorophyll alterations. All of these have occurred naturally. In X-rayed f e r c io ans lp i ic eu so su s variations have been found but these arc not sufficiently well marked to segregate clearly. Four of the natural variations have been crossed back with l ti hn ee s n of rr mo am l which they come. All have given the s^ p ris^ g result_of a hybrid-vigor effect. The Fp plants are either taller, lLf and bs rt 0a ;l “k “, earlier in flowering or more productive of grain. differences are small but measurable. Ii i ie +T i +n v ho el tv ee roo sn il sy a i ssingle gene this wo s uo lm de t bh ei n cg l em ao rr e than an accu pm aulat 01 rabi lon e gr on wo tn h-allolic dominant .... S factors. 512 It may also be questioned fairly whether these are actually the degen- < +e types that they seein. From evidence previously reported these reduced " may ^ive superior results in outcrosses. Since those mutations pre- ably origins.te in the heterozygous condition, the plants containing them ^uld be more vigorous than the homozygous individuals in the same line 3 d ere likely to be selected for propagation. This was actually the case aI1 the blotched leaf line that came originally from a plant selected as 1 !j0r in height of stalk and ear development to the other plants in the ^ ' self-fertilized progeny. This is additional evidence bo show why inbred lines are difficult to maintain in a constant and uniform condition. It mn'r also explain why seme of the poorest lines are so uceiul in Deduction" of commercial hybrids. For example, Iowa L317,C.I. 540 and 4-* are notably unsatisfactory as inbres but are used in hybrids that are widely grown. Combining ability results from a complementary action that is not clearly indicated in the homozygous condition and apparently involves an eauilibrium of genic material that is not as yet fully understood. 2. The reciprocal crosses reported last year, made between inbreas with extreme differences in kernel size (Rice pop and Reid dent) again showed significant differences in early growth. These differences almost entirely disappeared by flowering time. The combined average days to tasseling ana silking were 81 for the pop inbred and 66 for the dent. The two reciprocal crosses were 66 and 65. The crossed plants from the larger seeds flowered one day earlier. Differences in tillering also went with the larger initial prowth, where the seed was produced by the non-tillering parent. The average number of tillers this year is dent 0, dent x pop 2.7, pop x dent 2.1 and pop 2.9• 3. Plants grown in the greenhouse and transplanted to hhe field are sometimes shorter at maturity than plants grown from the same seed sown directly in the field. Very small, immature seeds from ears that are harvested at an early milk stage usually produce plants than grew to normal^ height and productiveness. This suggests that tall plants that are difiicuit tc pollinate might temporarily be reduced in height advantageously. Possibly better means could be devised to do this, such as bending the plants to the ground in the early stages of growth and allowing them to grow upright. The basal part could be held down by covering with soil, fastening with a wire staple or tying to adjacent plants- D. F. Jones 4. Considerable heterosis is manifest when Purdue 39 Is crossed with Connecticut 30, a reduced type of P39- The P39-G30 hybrid an 1942 producea 25-30$ more grain than P39- The hybrid also grew faster than either parent. The C30 type plant is recessive to P39 and the P39.C3G hybrid gives good monogenic ratios in both F2 populations and in backcrosses to C30. 630 arose in 1933 in a celled ear of the P39-16 stock of the Crookham Company, Caldwell, Idaho. Since there was no evidence of outcrossing it is assumed that C30 .̂s a mutation. The interesting question is whether the heterosis found last year in the P39.C30 cross was produced by the same factor causing the C30 plant to be reduced or due to other factors that may have mutaoed since the^ C30 was separated from Purdue 39- Crosses made last year may give information on this point. C30 was crossed by several different sub lineo oi Purdue 3/ maintained in different places and quite distinct in themselves. It will be interesting to see if as much hybrid vigor is obtained when P39-16 is crosoed by C30 as when other more remotely related lines are crossed. The data on hand are insufficient to justify any conclusion regarding the nature of the hybrid vigor encountered in this intra-inbred hybrid. It could bo explained by rhe 513 • teraction of alleles, divergent in function as suggested by East. Further ^,dY is necessary to determine whether the factors responsible for heterosis allelic or not. Whatever the explanation this phenomenon like hybrid vigor ZLeen different inbreds, may have its practical application before we under- , ^ fully the cause of the hybrid vigor. If the yield of Purdue 39 can o Uicroused 25% or even 10% by first crossing with C30 it would seem logical for ti e seedsmen to use the C30.P39 hybrid in production fields wherever P39 is rdinari3.y used, as the seed parent. Since it has been found that CJO hybrids ° equal if not superior to P39 hybrids, seedsmen might well utilize the^hybrid vigor of the P39.C30 hybrid in their seed fields to increase their seed yiei.d without sacrificing in any way the quality of the finished hybrid. 5. Effect of C30 on the production of new mutants. In the cross of P39 x C30 several cases of defective and germless seeas have been encountered. The number of segregating progenies has been small and consequently no rate has as yet been determined. It is our belief that a rate exceeding the normal mutation re bo will be found when more data are accumulated. Besides germless and defective seeds, a virescent seedling was found to be segregating in a selfed progeny of the cross P39 x C30. No such virescents ha\e been observed in either P39 or C30. The virescent when selfed produced 100%^ virescent seedlings. The inheritance of the new virescent will bo determined. Algo P39, C30 and the Fq hybrid will be examined cytoiogicaily. 6. A light yellow factor or yellow reducer has been found in a stock of white sweet corn, Early Pearl. In changing Early Pearl from white to yellow this character was observed. Such yellow reducers are common in certain oi the lata white varieties of field corn grown in the south but are not frequent- ly encountered in sweet corn. The ones we have always observed it in are^ B&rly Pearl, Sugar3weet or Cupid, and Hayes White. Those varieties are similar and probably have a common origin. The new light yellow is dominant over the intermediate or darker yellow and In the gives a good ratio in most sweet corn crosses of 3 light yellow: 1 darker yellow. When backcrvssed to the regular yellow a good 1:1 ratio of light: dark is obtained. If ouckciossed to light, yellow the kernels are all light. The light yellow cor.dition is homozygous intone" of our commercial inbreds C33, derived from the Yellow Pearl. At the eating stage of ears heterozygous for light yellow no segregation for the iight yellow factor can be detected, the color being a goed medium yellow. Apparently the color is reduced during the drying process. 7. "First” Maize Breeder had Crossing Plot at New Haven in 18jro. In the 1345 issue (Vol. 2, p28) of the Cultivator magazine occurs an interesting letter from Noyes Darling, a New .Haven lawyer and judge, taxiing how he developed a variety of sweet corn. The full letter will be published shortly, pro do bly in the Journal of Heredity. We enclose an excerpt giving his procedure the first year, 1836. ”rst year. I had a very err^y yellow corn, out quite diminutive in its growth - the stalks not over 3 ieet, in height, anu the jars not over 4 .inches in length. Late in the season I planted this in a patch of sweet^or shriveled corn, then considerably grown. As soon as the "ops or blossoms o- the yellow corn protruded, they were cut off, in order that the early corn might be impregnated only by the sweet corn. The result this year was yellow corn 01 the usual size and appearance." This then appears to be the first crossing plot in which one variety was^ detasseled to be pollinated by another although James Logan had cut tassels olf of corn 100 years earlier in bis experiments to determine whether pollen was necessary for fertilization. However Darling's experiment seems to bo the first time a maize breeder had detasseled a variety of corn in order to make a controlled pollination. From the sweet—flint cross, by selection he produced 514 0« rlv white sweet corn that matured on July 18 in New Haven, a very early -ora. He described his experiment in a concise, accurate fashion that would ('erve as a model for scientific reporting today. W. Ralph Singleton Cornell University, Department of Plant Breeding, Ithaca, New York Aberrant pericarp-color ratios. In last year’s News Letter (17:8-10,1943/> I reported a disturbance of pericarp-color ratios unlike that caused by the recessive zygotic lethal, zl. Selfed red ears gave progenies with approximate- ly equal numbers of red and of white cared plants instead of the expected 3-1 n: tic. Such red eared plants, when used as pollen parents in crosses with white fdve progenies with about four times as many whites as reds. Only part of the red cars of such cultures gave aberrant progenies. The possibility of this disturbance being transmitted thru the egg had not been determined. More data of the same kind and a few new data are now available. The new and older data are summarized in the accompanying table. Normal and aberrant pericarp and cob-color ratios Progenies Progeny Phenotypes and No. Line of line Parental No. cf of individuals Approx. No. No. genotypes cultures R-R W-R W-W ratios Remarks 9 d* 1 - W-R x R- R 2 26 2 1 s=fi (x) 11 651 182 3:1 Normal R-R 3 1 " U) 3 175 153 1:1 Aberrant 4 1 W- W x W-R _ 9 402 391 111 Normal " “ R-R 5 1 11 7 290 1125 1:4 Aberrant 6 5 — — x W-W 6 197 - 199 1:1 NormalR-R x " " 7 5 M x W-R 8 225 203 1:1 Normal W-R 8 6 (x) 8 125 - 114 1:1 Aberrant W-W 9 7 W-R , v 6 - L40 40 3:1 Normal *M» (x) 10 7 " (x) 1 - U 11 1:1 Aberrant The pollen parents of the two Fp cultures shown in line 1 were from the same stocks of chromosome 1 markers, P br f an g_s, both homozygous for red peri- carp and red cob, R-R. The pistillate parents were from unrelated stocks with colorless pericarp and rod cob, W-R. Of 14 F2 cultures, 11 (line 2) showed normal 311 segregation and 3 (line 3) gave aberrant ratios approaching 1:1. Other F] R-R plants were backcrossed as pollen parents to stocks with colorless pericarp and white cobs, W-W. Of 3.6 such backcross cultures, 9 (line 4) gave 515 i Tl ratios and 7 (line 5) gave aberrant ratios approa n co hr im nan g ̂ d plants (line 6 Gix) and eight red-cob whites (line 7) o f fe Cl ti^ hr eo s as o ec ru rl at nu ur es were again backcrossed this lime as 2iS ^ ^H ln &ll t' eg a pv ae r en no wr sm ;al 1:1 ratios. Eight rod eared pl 4 ants (la iI nid eJ l 8 ) ic ro on md tb ha ec sk ec ross cultures when selfed gave only no aI b\ er, ran ̂ to i cy u lr te ud r- ec so .b whites from the second backcross cultures n (o l^ ma ef r 9a )t io gs a veo n soiling and one (line 10) gave an apparently abnormal ratio. In summary, it should be noted that red eared, plants of aberra n nr t u cs ue ld t ua rs e su ollen parents in backcrosses to while, tra r nf s' mS ivr tl - -n hc oe to ̂ some but £ T t o all cultures of the next genera n t iot ni .l la Wte h enpa ure sn et ds ir. such buckcrosses, no disturbanc f e , xw s^ T shi on wno r ia nt ti ho e n , but both red eared plants and rod-co n oo r wra ha ii t" es s®n ® or fa t ti ho an t give aberrant results when grown one further generation. Fr.)m a31 this, it is clear that the _ dr i4 sturbing facto r ( ip sr es cu am ra rb il ey d o bn ye - eh alf) of the female gametes and oy !® e" pt ah re tn h ma alf t) e ,ro af l lt yh e functioning male gamstes. in xts adverse effect on the functioning of male gametes, it xs simi ( lN ae rw s tL ce t tt he er g1 a7 : I7 k, 1 ’t1 e9 n4 t3 a) t. i veI l ya m th> e therefore, assigning to it tentati - / symbol Gal. Since there is evidence (tho slight) of crossing over b . e- t„v wn e_ ec no l ei sL , r ta nn e so e bn e e .abl ve als u ac ta en d b be y use of F2 or ba2 ckcross ratios onp le yr c we hn et n o aTZ f d ec qr uo as ts ei ng ever cah rdotormSdlirecUy,^however? the x'atios of aberra 1 nt to noC rr mo an l ( c) u l1 tu7 rf er so m reds of aberrant ?2 cultures and (2) • fn rd o/ mo r p rr oe gd e- nc io eb sw h oi ft e res wo f backcross cultures where to ga ^ x ri el dl s l at ro e p ua sr ee dn t as s o tf h et he backcrosses. In these cases, the t ro a tn io or sm al of c au blt eu rr re as n t should be quite independent of the percent of lunctioni g Ga pal Lon. Limits can be set for the two variables by use of F2 and o bf a cu kd c roto s sw h ri at te i. o s Thus, the observed 53 percent red eared pxan-s of rg "1 ub ie & ia ccounted for by various combinations of the two from zero crossing over with 6? with zero functi ^on ri on eg n tGa r ep do el al ren e, d po li- ant i .-n t s b ha ec k ocr oo ss es rc vu elt au ^r pe s indicate vav re ir ay b ld ei sfferent limits .or u a tm oc oi y twof ro vm a riz ae ro 1 cr ,ossing over with Z!% functioning ua r pol len't t' o S 20 5 fu cn .c ot si .io ni Bn g to pollen. Since tho crossov b el rl pe el ra cm ee nt af gor e jt mh se t two ty^s of cultures, one of thre namely."(1 e conclusions m) usm ey fh oy lp lo ot wh ,e sis is wrong (2) my calculations arc wholl o yr mO m) c cp uo rl al te cn , functioning is affected adversely much l mo ou reh ic wh h eIt n c e a Pp p -l i - e xd are heterozygous for Ca t I hf a n when tnoy t ch ae i" rl ya t ot er j i £s _ •true, the gamete factor, toi, may be regarded as dominant as is Gal. R„ A. Emerson 516 Cornell University, Department of Plant Breeding, Ithaca, N. Y- and University of Georgia Department of Plant Pathology & Plant Breeding, Athens, Georgia Chromosome 1 . Ts^ + Cross ' x Kn inbred (ts3 kn) 'S3 + TS3 Kn + + -t Kn Total 73 2 5 6B 153 % recombination = A -6 Chromosome 2. Tetraploids In the course of his intensive work on tetraploids, L. F. Randolph created a stock containing the genes lg,, £l, b, vA -and a corresponding stock containing the dominants. Both stocks were homozygous Ap, A2, A3 and also AS which is necessary for definite classification of the genes B-b in the seedling stage. The stocks were multiplied and then selected for distinct expression of the four marker genes. Following this, J. E. Welch studied the linkage relations of plants duplex for each of the four genes v/hen backcrossed to the multiple recessive. Beginning at this advanced point, I can contribute some additional information. + + + The cross of a plant duplex for all four markers +__+_ + + lg gl b v lg rl b v lg gl b v lg gl b v by a multiple recessive one lg gl b v should give as a parental lg Rl b v + + -f + class ratio four plants simplex for all genes lg gl b v to one lg gl b v + + + + jg gl b v + + plant duplex for all genes lg r,l o v to one multiple recessive Ig-d-k. lg gl b v plant lg gl b v . Numerous other arrangements are possible in plants lg fry IjL derived from crossover gametes; but for any one gene, the individual plant, should have the recessive allele represented either two, three or four times. The last type is obvious phenotypically since it is homozygous for a recessive marker. Further, a cross of this nature should and did segregate in the ratio of 3-6 - 5 dominants : 1 recessive for each oi the four genes. 517 If several individuals with dominant phenotype are selected from h « backcross progeny, and again backcrossed to the multiple recessive, S chould find that certa o in ne » o‘ f1 UU t h' e ir prog, enies give simplex ratios for all four gene members. Twenty individuals were tested; their distribution is as follows. 2 duplex ratios for all four genes 1 duplex ratios for lg, gl and b; simplex ratio for v 1 duplex ratios for gl, b, and v; simplex ratio for lg 1 duplex ratios for lg and v; simplex ratio for gl ana b duplex, ratio for v; simplex ratios for lg, gl and b 2 duplex ratio for lg; simplex ratios for gl, b and v 9 simplex ratios for all four genes The study of progenies, derived from backcrossing plants simplex for h p-ene to the multiple recessive stock, should give the most dirget measure of recombination frequency in a tetraploid for comparison with those in similar diploid stocks. While 4,315 mature plants were studied, obviously only part of +hose may be used, in the calculation of recombination frequencies from simplex ratios for any given region. The aata^are tabulated as a three-point test for lg., gl and h and as a two-point test for h. an jL. This enables one to utilize larger numbers than would be possible in a /-point tabulation. No records wore used unless the ratio of dominant to recessive allele was a good fit for a 1:1 ratio. In this manner, any possible effects of either differential viability or poor expression are . at ao mr,iinniimmunrm-. NNoottee that the total is smaller for the 2-point test a number of cultures since the exass (+ 1 + 1033 (+ + i m a ® gl b 1036 (b 427 (♦ gl b 196 (+ 352 ’ (lg + + 192 (b + m 1622 , (+ + b 181 ' U g gl + 219 786 b : 836 + D/P.E. = 1-9 779 v^: 84.3 + D/P.E. = 2.4 o2( + gl + 55 1500 lg 1466 + D/P.E. = 0.9 &2 FV q 15-1 4/3(F-F) 124.5 2.8 2(B-P) 142.0 20.3 (2Fp-P) 127.6 5.9 2(2F2-P) 118.4 -3.3 i(F-B) 89.6 -32.1 2(2Fr E) 113.2 -8.5 Mean 121.7 ((22FFo2-B) = 11.3; should bo 0. Lindstrom's data probably are a fair representation of the usual result - see Neal, J. Am. Soc. Agron. 27: 666. The seven estimates of (1-k) na are expected to be (2 hF oo m= o gB e) n eo on u s th ae n da dditive scheme, with no restrictio a ns st o a sd e tg or e le i, n kd ai gr ee ,c t oi ro n or other variation of dominance, or variation o. Alpha. In the event of no significant departure from the addi m te ia vn e es st ci hm ea mt ee to hf e (1 -k) na may bo of value to the breede r re so wl iu tt hi oo un t i .n ut ro -it s factors. The quantity (1 e +s t ki )m at ne as t oo rt a (l n er t an +g e n ko af ;g enetic variation for the speci a fs is co r ctm re on st s. " iD -is ht ^a en ece from the lower extremity to u pp re qr ie sx t nr jsterility on ears, pollen also low T2-9& x 2-Qb serni sterile T5-7a x 5-7c 29̂ > sterility on ears (pollen also low) The low sterility ras thought to be the result of survival oi a certain class of spores which ordinarily aborts. In crosses involving two inter- changes in which the two breaks are close together and in the same relative position with respect to the spindle fiber (the same interchange ha/ing .̂ts break in each chromosome closer to the spindle iioer than does tne other one) certain spore classes should be deficient for only one short region. According to the cytological data available, in T2-bc the breaks are in the long arms at .3 and .25 respectively from the S.F. in chromosomes 2 and 6; while in 2-6u they arc also in the long arms but at -4 and .4- Deficiency tests for genetic loci in the two ?i hybrids showing lew sterility were all negative: for T2-6c x 2-bd : ms, si, pb were nested for chromosome 6 X£ £i vA, ha2, ts were tested for chromosome 2. T5-7a x 5-7c : by gl6 for chromosome 5 si, bd, Kit ra ij. for chromosome 7 It seems probable that none of the genes tested is in the region suspected of being deficient. C. R. Burnham 6. Red glume collar. Certain inbred lines and genetic steexs show^a band of rod color near the base of the glumes of the tassel. Lc0t shocks are green at this point. The color may show only when the tassel is fully out of the boot, but it may show earlier. A few segregating progenies indicate 524 t in these cases the rod differs from green by a single dominant factor. \backcrosa test involving this character and also Y and PI indicates t!iat red glume collar is closely linked with Pi (6.6$ recombination), but tie data did not indicate the probable order. Another red glume collar character is found in 5 pi stocks, but in cultures segregating B-b, the collar color has always been associated with B. C. Lazaro and C. R. Burnham Young tassels of both types b pi red collar ana B pi red collar were wrapped up in black paper to exclude the light. In the first type (linked with Pi), the collar color developed in all cases in the absence oi light. When the second type (associated with B) was bagged, the sun red color on the glumes did not develop, but the collar was colored, altnough not as intensely as that in the typo linked with PI. It appears, therefore, that the collar color is not a sun red color even in the type which is associated with 3. C. Lazaro 7. Trisomic tests with unlinked genes. Trisomic tests for chromosome 6 and the following genes wore negative: zb, gl6, £19 (trisomic plants had an excess of &1 progeny as c /./'.pared with the 2n), and v9« A seedling dwarf (one of Stabler's designated temporarily as de-3) may be in chromosome 6 by this trisomic test. Linkage data with other factors were obtained along with the tests for linkage in chromosome 6. The possible linkages are as follows: Segregating for R.ecom. Genes N nev/ characters Y2 for indep. test ± S.E. pr - ws 104 3:1 P = .02 35.5*6.1 Wc - si?* 164 15:1 P = .02 Y - gl-11 233 3:1 P = < -0 1 33.5*3.3 Y - w (in gl6 202 3:1 P = < .0 1 27.0bc3.3 culture) FI - gls-3 276 3:1 XD = < .0 1 12.0*3.6 gls-3 - t w ^ 276 excess for 15:1 P = <.01 1.0*jl.7 FI -tw? 276 it P = <.01 1 aleur. factor - tw3 579 n P = ..01 3b .0x6.2 FI - tw3 213 i 0 — .02-.01 gl - tw3 561 it P = <.01 28.0t5.6 * This silky is one that appeared in an F2 of a single cross here. *#Thie tw was linked in coupling witii the gls-3» one cf 3taulex‘'s muoa.nbs. Negative results by the for independence test were ’obtained for the following linkage tests: .zb with Igj W£. with Y PI 3 rg; gls—1 witr u_ _lg. nl?5 nl? with ""id l£j as-3 with su, pr Y colorless aleurone (9:7). .gib with Y; g!9 with 1 bt? and z£> with X and colorless aieurone (3:1) C.R. Burnham and N. Klein 525 University of Missouri, Department of Field Crops, Columbia, Missouri 1. Gene Variability. The study of R alleles which Fogel and ^ ,'d xn the :t9A3 News Letter has been continued, r wep io tr ht the„ addition o_ p0*h e, or types and with f^,avt+hheorr «s+t.hum a d vy noff s«pne*cciiffiicc mmooddiiffiieerrss coff RR I n and of env ac it ri oc nmental conditions affecting it. All or nearly axl of 22 Rr*s tl 'ie o r* i2 ±rT>r1 ginally included appear to be distinguishable in their upon plant color, but since come of these differences are slight f' raouire confirmation in experiments in which modifier action may to ̂ ^ nd!d more critically than is possible by repeated parallel backcrossmg. For this purpose ve have used colorless aleurone mutants oi several f the original Rr allel.es, since as previously reported spontaneous °rions of have no appreciable effect upon tf*e plant-color action, snr example six alleles (Boone, 997, Cornell, Quapuw, Ponca, and u. ac. û mitv) form a g-oup characterized by rather strong pigmentation, -noug i distinguishable in parallel backerosses by slight though consistent differ- Colorless aleuxone mutants of Cornell and Quapaw were crossed with nther"members cf the group, and baokorcssod by rg. This fields progenies ?n v,hich the Cornell or Quapavv phenotype may be compared with the phenotypes f similar alleles i.n sib plants, the aleurone color difference providing 'i completely linked marker. Bush comparisons, so far as they have gone, infirm the reality of the small differences observed between members oi this irroun. A similar method may be used for the study oi "non-linear variation in the action cf the different alleles (News Letter 1913, png^ 20), and here the mutant r^'s may be supplemented by naturally occurring r* We are using the latte- chiefly for this purpose. The alleles of B (News Letter 3913, page 22) appear to be fully as variable as those of R, and since the range in plant-color phenotype is evan wider, they may be better niit- d to tho identification ot small differences. . Aiming H £*' s compared, 6 were selected as standards to represent distinct levels spaced roughly between b and 3, and in each ox these a stock of B-gl rS was established. These alleles listed in ascending order of effectiveness, are designated as follows: 1.] ** (Boone) 3. (Clarage) 5. B* (Lookout) 2. Bw (Moung) A. Br (La Paz) 6. P" (Seattle; Additional Dw,s, both from existing stocks and from mutations various B's, have been crossed each with the standard t‘*r£k strains -hie. ̂ appear to be just below and above them in effectiveness, ana lx.ckcronses o* ihese hybrids will determine their position in the series. For further limitation work, Anderson's In? f e B G X l ^ ) stock is being extracted in homozygous combination with v* since Bw mutations induced m this stocK any be crossed with the naturally-occurring alleles to produce b&ckcross progenies with virturaily complete linkage or mcncor genes. Miss Elizabeth Somers is making a detailed histological study or the development and distribution of anthooyanin under the action of R and oi 3. 2. Gene Action. Among tissues capable of anthocyanin production there are marked differences in response; cells of certain types produce 526 «vanin readily with any E-allele above the ES level, wh a irf le , c' eL xle ss om fa y produce anthocyanin only in the presence of ° ih tc h e “ stronges t example, among epidermal cells of the leaf, there are differences in the reaction of the Ion,, narrow cells over the the long and short surface cells, the stomaual cei.Lo, ta V1 e ht ah ie . ,>specialized cells at the bciue of the hairs, and the pair ^ er di raceous and ouboriaod cells- Anthocyanin is fo 1 rmed much moie f r et ah de io lp yi dennis than in the underlying mesophyll cells, but t i^ nc p thh e^ l a c k i n g sectors of japonica plants it is producoa abunda • ̂ ntr le- yo phyll cells also- The same is true of certain white ana l ve irs e sa cn ed n , in normal green plants the mesophyll cells of the a S ui rir ch l el ack chlorophyll) are well colored by even relatively weak a W lit lh e ls et .r .o ng B alleles, green mesophyll cells containing anthocyanin aie lore frequently found. The alleles of R and 3 thus provide a series of reagen a tn, sa ,k ‘ sf oo r t ot he study of tissue differentiation. Thirty years ago  Kk eir es b. l ea ^n d others showed certain interesting relations between an S tt he or cn ys a na in nd the occurrence of oxidase systems detectable by the h i uc st eo ch oe fm ical test-substances. Mr. Fogel has undertaken a study oi . ki hn id s with maize, which is however still in a preliminary st-ige. The study of competitive action of certain A alleles (News Lette i rr e 1e 9 42 31) , is being continued in collaboration with John R. Laug d ho nm ain na .n t a .hc et ion of aP upon plant color i? manifested *itha:U o, the, visibly weakened A alleles tested (A", A--, A .-). Ih , hA et i a l( lb eo lt .h s obtained by Rhoades, out of a by Dt) are purple plant d i tst yi pn eg su ished from A by their reduced effect upon pericarp col t oh re .se a Wr ie e nc ompared with A in aib plants (in baclccroES progenies e mt) a. r kt oh oe y o ̂ho. slight but distinct reduction in anthocyanin pigmentation of the plant as well. The dominant effect of eP upon plant color is shown also, to e x at en st l, i gb hy t certain A’s which appear to have full plant color and pe c ro il co ar rpo ffoct. The different A's used wore extracted, alt t aa rc kc pr ao rs as li ln eg l to a C R, from various stocks, chiefly the Indian grai as n sf o uu sn ed da tion material for the H and B studies. With s o onc me e b Ae t sw e te hn e A d/ .a lP f ^a in d A/i sibs is clear enough to permit reasonsbiya p cr ce ud ric at ti eo n of the genotype at the flowering stage, and this ^ent a an fy i b ce a Um cad ne somewhat more accurately by testing tne extracted d pif if ge mr enc •e is ;due to the presence of varying quantities of yellow pigmen t to it nh e purple. Sith ocher A ' 8 and with Ab, no difference i« The aP reaction thus serves as a sensitizer .or tho rccogni- b iet ow ne e on the A alleles, and indicates the occurrence of conside ad rd si ct ii eo nal allelic variability at this locus. Conversely, .he e th xe t ee nf tf e oc ft varies among different polo alleles obtained toy mutat A it o( nH e fw rs o mL etter, 19X3, page 21), when these are tested against A al l coof m mt oh no A.p ale alleles showing the dominant plant color ef.eeo have. 527 . nt brown pericarp action; the two pale aleurone alleles with d o rn eun ca e ssive and A^Jgive negative r brown p-'1 esults 1 in p ara~ llel tests, Mr Laughnan is nuking a chemical and spectrograph!c study of th^ ‘ involved in the action of the A alleles, and is developing mo, u< s fifth/quantitative study of the mixed pigment phenotypes. O Spontaneous Mutation. The frequency of spontaneous nutation to inrJess aleurone types varies widely in different K alleles 0 . lc.e mos c lftb1e of the alleles studied is Rr (Cornell), which yields r mutations .t’n • rate of about 2 ner 1000 gametes. At the other extreme are a low which give no mutations in populations of 25,000 to 100,000 game to s. As previously reported, differences in mutability are inherent m +v_ k,ene itself, since they are maintained when a highly mutable and a ret mutable allele are combined in a heterozygoto, so that tne mutations t occur in orecisely comparable cells. This comparison is made possible hv̂ the fact that the mutations affecting aleurone color do not affect plant :oicr and in a heterozygote R1 R2, in which plant color is distinct i it n ,ne alleles combined, the identity of the gene mutating is readily determine. For example, when R (Cornell) is combined with an R e v i e w mutability, the mutants’produced by the ?± plants are almost exclusively r '^omei.j. In addition, however, there is a pronounced effect of modifiers upon the frequency of R ->r mutation. Homozygous R (Cornell; stocks extiacted fpom crosses of the type mentioned show lowered mutation rates, in some cares much lowered. Different homozygous strains extracted from tne sumo jq plant show distinctly different rates. Mutations to colorless pit-.ns types (Rr ->RS) occur at appreciate rates in certain alleles, and the variation between Rr alleles in frequency of mutation to Rg appears to be uncorreiatod with that of mutation to r . R (Cornell) is very low in frequency of mutation to PS, while certain othe R alleles yield plant color mutations at moderately high rates, none however approaching the frequency of aleurone color mutations in k ^Cornet). The frequency of mutation to rr and to R£ in the same plant (male 2 is r,a ce^ ) tested extensively in 2 plants of R (Columbia), with the following result. Plant Mutations to rr Mutations to 1 6/12,525 3/11,304 2 J2/JL&1 3/ 8.020 Total 11/20,984 6/39,824 Mutations of Rr to intermediate levels appear to Do very rare. On .he contrary B mutates frequently to intermediate levels, and no nru^acions >f B to o have been found. The alleles occurring by mutation differ ddely in level of action. In this respect E resembles 4 , which as previously reported mutates frequently to different levels ol a? type and rarely if ever mutates spontaneously to a. 528 , Comparison of X-ray and Ultra-violet Mutation. Following the . * nt on X-ray and ultra-violet imitation of A previously reported expe? (News Letter 1941, page 4!5~47, 1942, page 24- 27), Roman and I set up a 'what similar experiment with Ab. This was desired to take advantage soc6e '' fact that the spontaneous mutations of Ab are to an intermediate °neJe and are therefore clearly distinguishable from the effects of J ficiency. The previous experiment had shown that the apparent mutations ••dueed by X-rays were in fact minute deficiencies, and that the apparent % ati ons induced by ultra-violet wore distinctly different and behaved as .j., yl0y represented transformation of the gene to a recessive allele, It did not, however, exclude the possibility that the ultra-violet muta- tions were still more minute deficiencies, or cases of destruction of the singie gene. With Ab this distinction could be made, if ultra-violet nutations actually are mutations of the type represented by spontaneous mutation of the same gene. Extensive pollinations with untreated, UV-treated, and X-rayed pollen of a single A_b plant wore made upon ears of a Dt, and numerous deficiencies and mutations were identified in the progeny. But the experiment failed in its main objective, because the natural frequency of nutation of A"’ to aP Is so high that nc significant increase in aP mutations was produced by the treatments used. The results, however, give additional support to the indication that the UV mutations are true gene mutations in two ways. (1) No apparent mutation of Ab to a was found in the very extensive ultra-violet sories. (2) Among the endosperm mosaics induced by ultra-violet treatment, there wore several, cases in which a mosaic of clearly pale aleurone tissue showed typical dots of Dt type. Although an endosperm sector does not permit progeny testing, these can oi*ly have resulted from mutation of A° to up, induced by the ultra-violet treatment. An endosperm mosaic of pale appearance could result from any one of numerous causes, but it could not provide a background for visible dots of A_ tissue unless it resulted from a change in A-action, and this background could not be pale if the A loss were duo to deficiency. Tne effect of ultra-violet treatments upon A.b mutation is sufficiently frequent for detection in th- endosperm and not in the embryo because of the much higher frequency of inuucecl alterations in endosperm than in embryo, which has previously bo . r parted as characteristic of ultra-violet treatment. This heightened frequency of endosperm altera*4 •' ns may be usea to simplify various studies involving ultra-violet effects, and to make possible certain studies which otherwise cou!-i not be carried out. For example, it would be very desirable to determine the effect of varying ultra- violet wave lengths on the frequency of mutation. The action spectrum for A-loeses in endosperm has be<..n determined, but these include both deficiencies and mutations, and presumably consist very largely of deficiencies. It would net be possible to make significant comparisons of wave length effective- ness in inducing mutation if the mutations could be identified only by the growing and testing of progeny plants. 529 The use of Ab, with recognition of mutants by the aP phenotype, as r-ribed above, is effective for identifying positive cases of mutation d65the endosperm, but it is not suited to quantitative work because of f luent failure of aP sectors to color positively. Laughnan and I have therefore made use of a different method, which permits identification ̂ alterations in the endosperm but with confirmatory tests on the plant grown from the accompanying embryo. pollen of homozygous A A with the recessive markers &13 and j_ was S3d on oars of a^Xj/aP. The x-ray mutants a-XL, a-X2, etc., are inviable when homozygous and in all possible combinations inter .se, and sectors homozygous or hemizygous for them are also inviable (News-Letter, 19/? page 25). If all X-ray induced A-losses involve the loss of the associated viability factor, X-rayod pollen will never yield a colorless ge0d or sector; if any apparently colorless or sectorially colorless seed is found, it may be tested by growing the plant to determine whether the female gamete was a-Xl or aP. A colorless seed yielding a plant not heterozygous for eP is selfod or tested for the recessive markers to exclude the possibility of pollen contamination. The A-losees shewn by aP tissue include the deficiencies plus the mutations among the seeds from aP gametes; those shown by a tissue include the mutations alone among the seeds from a-Xl gametes. Control pollination by a C R on a number of ears of the female stock show that (, gametes of aP and~a-Xl functioned in approximately equal numbers. In the limited populations now completed, X-ray treatment has failed to yield colorless seeds or sectors. Ultra-violet treatment has given 3 proven canes of colorless sectors. The total number of A-losses in endosDorm in the ultra-violet population on which the tests have been completed was 92. This indicates a ratio of deficiency to mutation of about 86:3 under ultra-violet treatment for the A stock used in the experiment. This is not greatly different from the proportion found among progeny plants representing A losses in the embryo. The induced alterations cl : ^iod as mutations are subject, to the same reservations regarding their genetic nature as are the ultra-violet mutations identified in progeny plants following treutrr*ont ox A. The method permits the determination of relative frequency of mutation (in this sense), with a fraction of the effort required in determining mutation from progeny plants. By this method it is feasible to compare the effect of different wave lengths upon deficiency and mutation simultaneously, and to compare different A alleles in relative frequency of mutation. Wi^h slight modifications the method may be used also for the identification of gene mutations of Ab critically distinguishable from the effects of gene- deficiency. The results of the above experiment have a further interest in connection with the problem of the endosperm-embryo difference in frequency of ultra-violet alterations. The cause of this difference is unknovvn, and the most plausible guess has been that it is somehow connected with the difference in breakage-fusion phenomena in endosperm and embryo, which might appropriately be termed the McClintock effect. It might oe expected that deficiencies, initiated by equal effects of the treatment upon the two sperm nuclei, might differ greatly in frequency of realization under 530 very different conditions of endosperm and embryo- But this experiment ? j-cates that the heightened frequency of alterations in the endosperm 1 -̂ eS to mutations as well as deficiencies. Dh.Ue the various experiments with induced mutation of A and Ay indicate ̂ultra-violet treatment produces true gene mutation and that X-ray treatment does not, they are disappointing in their failure to yield •nduced gene mutations which may be established in stocks subject to ^itical "analysis. This is due to the failure of the A^ experiment described on an earlier page of this report. The advantage of regular soontaneous mutation to an intermediate allele, which makes Afi suitable for this experiment, applies also to Rr, since its spontaneous mutations 're j-egularly to R2 rather than to ry. In the case of Rr distinct alleles are available, including types with varying frequency of spontaneous mutation Mrs. Elena Perak has undertaken an extensive study of the effects of X-ray and ultra-violet treatment upon mutation of various Pr alleles. 5. Effect of X-rays upon Dominant Mutation of a. No dominant mutations have been found in X-ray progenies of maize in experiments in which hundreds of recessive mutations have been observed. The evidence against the occurrence of dominant mutation induced by X-ray is however inconclusive, for the following reasons: (1) The number of genes capable of showing dominant mutation may be iuuch smeller than the number capable of showing recessive mutation, since many genes may be already fixed by natural selection at a level maximal for gene action. The possibility of Inducing dominant mutation can, therefore, be tested critically only with known rectissives. (2) Among known recepsives many may be themselves deficiencies and, therefore, incapable of dominant mutation. Critical evidence of failure to nutate to a dominant allele therefore may be obtained only from recessive genes which have previously been known to mutate to a dominant allele. (3) The only recessive alleles which meet this requirement are the variegation genes, which may be regarded as unstable recessive mutating frequently to a dominant allele. In these the spontaneous frequency of dominant mutation is so high that an effect of X-rays in inducing additional dominant mutation probaoly would not be appreciable. It is possible to avoid these difficulties in the case of one gene. The recessive has several known dominant alleles. The effect of Dt proves that it is capable of dominant mutation. In the absence of Dt it is not mutab.le, and would therefore permit recognition of even a slight effect of X-rays in inducing mutation. Since the effect of mutation is recognizable in minute sectors the treatment may be applied in a fairly advanced stage of endosperm development, so that many hundreds of cells are tested for mutation by the examination of a single endosperm. It is therefore possible to test for the occurrence of this mutation in practically unlimited populations. The seed to be irradiated was produced by the cross a a X A a, both parents being homozygous for dt dt and for the complementary factors required for aleurone color. The endosperms of half of the seeds produced are A a a. These serve to indicate the size of sectors resulting from geneti 531 2U. riterations induced by irradiation at the stage chosen, since induced Efficiencies of A result in sectors of colorless aleurone. In the color- less seeds, induced dominant mutation of any one of the 3 a genes would -suit in a corresponding sector of colored aleurone. The colored, seels thas provide a basis for calculation of the number of opportunities for detectable mutation in the colorless seeds, anu a basis lor comparison of the relative frequency of induced dominant mutation and deficiency. Treatment was applied 73-31 hours after pollination. The mutability of the a gene in both parental stocks was tested by crossing with Dt, a^l being an a allele v;ith negligibly low dominant mutation rate in the presence of Dt. From the results oi these crosses the number of dominant mutations which would be expected in the a a a seeds under the influence of various doses of Dt may be calculated. Tho results show failure of X-rays to induce dominant mutation in a population estimated at 5,700,000 cells, each containing three a «s capable of mutation. The cell population o*' equal si.se in sib seeds yielded approximately 100,000 losses of A (deficiencies or recessive mutations) flora cells containing only one A gene each. The number of mutations r which would have occurred in the same populations under the influence of pt calculated from the test crosses mentioned, was over lb,GOO for a "Angle dose of Dt, or about It times this number for homozygous Dt Dt Dt seals. L. J- Stadiar Crrnegio Institution of Washington Department of Genetics, Cold Spring Barber, Long Island, N.Y. During the past fow years, a number of terminal deficiencies of the short arm of chromosome 9 have been isolated. Each deficiency arose as th- consequence of a meiotic breakage of the short arm of chromosome 9 following crossing over in plants heterozygous for a chromosome 9 with a duplication of the short arm or fora structural rearrangement of the segments of chromosome 9. In each case, the extent of the deficiency was determined at pachytene in the plant3 which had received a normal ciiromcsome 9 from one parent and a recently broken (deficient) chromosome from the other parent. Tests showed that deficiencies which ranged from minute to one-third of the distal segment of the short arm were all female transmissible. Those which expended int^ the first distinct chrocomere vanr transmissible through tne pollen. Done of the longer terminal deficiencies were male transmissible. Because o'* the male and female transmission of the vary short terminal deficiencies, plan-s which were heterozygous for these deficiencies were sol* -poulinated so determine if viable endosperms and embryos could be obtained which were homozygous for these deficiencies. In these Fj_ plants, the normal chromosore carried c and the deficient chromosome carried C. The C mutant is located in the short arm within the 5th or 6th chromomere from the distal end. In these ih plants, 30 individuals were classified as having received a broken chromosomes 9 which was deficient for oixLy the knob, sell-pollinations oi these heterozygous deficient plants gave typical ratios of d o to 1 £. endosperms and embryos in both classes of kernels were normal. Plants arising from both tho C and c kernels - vo likewise normal in appearance. Cytologica.l 532 examination of some of these F2 plants showed the presence of the two deficient chromosomes 9. It may be concluded that a homozygous deficiency of tho knob does not obviously alter the appearance and functioning of any tissues. Seven of the original Fj_ plants were classified as having a chromosome 9 which was deficient for the knob and the adjacent segment of thin chromatin which joins the knob with the first distinct chromomcre. Self-pollinations of these plants likewise gave typical ratios of 3 C to 1 c. The endosperms and embryos were normal in appearance. In all 7 cases, the seedlings arising from these kernels segregated in the ratio of 3 green to 1 pale-yellow. The pale-yellow seedlings are normal in morphology but die following exhaustion of food supplies in the kernels. Linkage of the pale-yellow phenotype with C, carried by the deficient chromosome, was obvious in each case. Through genetic and cytological meuns, it was possible to determine in each case that the recessive pale- yellow phenotype is produced as a consequence of the homozygous deficiency. Intercrosses between plants heterozygous for these 7 pale-yellow mutants showed that all 7 were either identical or allelic. The recessive mutant yg2 is known to be located close to the end of the short arm of chromosome 9* Combinations of a chromosome 9 currying yg2 with any of the 7 deficient chromosomes 9 produced only normal green seedlings and plants. It may be concluded that the deficiencies which product the pale-yellow phenotype are not long enough to include the Yg2 locus. In six Fy plants, the broken chromosome 9 was classified as being deficient for a terminal segment which extended into and included a part of the first distinct chromomero. Those deficiencies were slightly longer than those which produced the pale-yellcw phenotype. Following self- pollinations of these plants, normal F2 ratios of 3 C to 1 c appeared in four of tho six cases and a slight reduction of the C class in two of these cases. When these kernels were germinated, white seedlings segregated in ratios expected from a recessive mutant. In all cases, linkage of the white seedling mutants with C was obvious. It was possible to determine for each case that the white seedling phenotype resulted when these seedlings were homozygous for the deficient chromosomes 9. Intercrosses of heterozygous deficient plants of ail 6 cultures were made to determine the allelic relations of the white seedling mutants. White seedlings segregated in the F^ following all 15 combinations, indicating that the white seedling mutants were allelic if not identical. Intercrosses between plants heterozygous for the 7 pale-yellow producing deficiencies and the 6 white producing deficiencies gave rise to the typical pale-yellow phenotype in one-fourth of the progeny of ail *2 crosses. It was determined that the pale-yellow phenotype arose following combinations of the tvo deficient chromosomes in u zygote. Thus, the deficiency mutants pale-yellow and white are allelic. Pale-yellow is dominant over white. This would be expected because the residual hcr.o -ygous deficiency following combinations of the two deficient chromosomes is only that which would produce the pale-yollow phenotype. Plants heterozygous for the 6 white seedling producing deficiencies were crossed by plants homozygous for yg2. In the progeny of all 6 crosses, a ratio of 1 green plant to 1 yellow-green plant appeared. Appropriate tests showed that the yellow-green plants were those which had received the 533 deficient chromosome 9 .from the heterozygous parent. Therefore, it may be concluded that the white mutants are allelic to yg2, with y&2 dominant oVer white. This would be expect .d if the terminal deficiencies causing the white seedling mutants included the locus of Yg2. From the pcint-of-view of genetic analysis, the pale-yellov; and white seedling mutants are comparable in all ways to other known recessive mutants in maize. The allelic expressions oi pale-yellow and white and yg2 and white, ana the non-allelic expression of pale-yellow and yjg2 would be difficult to interpret following a purely genetic analysis. These results are readily interpretable when the cytological conditions are known. The phenotypic expression following combinations of any two of the three mutants may be considered a reflection of the residual effects of over-lapping deficiencies. The mutants pale-yellow and white are repeatedly produced following the meiotic breakage of chromosome 9» Among 2577 such recently broken chromosomes 9 which were tested, 55 gave rise to the pale-yellow phenotype and 33 to the white phenotype. In contrast to most mutation inducing agents, the chromosomal breakage mechanism is a "mutation1' inducing process which "induces" the same mutant time and again. Barbara McClintock Duke University, Department of Botany, Durham, N.C. Unfortunately, I have been unable to make any worth while contri- bution to the News Letter. For the post few years my genetic research has been largely restricted to an attempt to keep some of my stocks from extinction in hope of better times to come. I have, however, made fairly satisfactory progress with the sweet corn breeding. In a randomized block test that I ran last summer one oi my hybrids out-yielded Golden Cross Bantam by about 35$ (dry weight of shelled grain) and yielded about 90$ as much as Trucker’s Favorite. This Hybrid is perhaps 10-lk days earlier than T. F. and might average a little, perhaps a day, later than G.C.B. In quality, it is about the same as G.C.B. In what amount to "blind-fold" tests since the culture numbexs^ meant nothing to the tasters, this hybrid got 15 votes and G.C.B. got 13 in direct comparison, a pretty good 1:1. Ears are slightly bigger but net quite so smooth as those of G.C.B. In a smaller yield test planted about six weeks later, (hotter, drier weather and shorter days) this hybrid showed up much better in comparison with G.C.B. loana and G.C.B. are the two sweet corns recommended for this area. Ioana was a little better than G.C.B. in the early tests but not nearly so good in the later test. H. S. Perry 534 Institute Experimental de Agricultura Y Zootecnia Departan^nto de Genetica, Caracas,Venezuela 1, Flint and Dent Corn. The improved yellow corn, Maiz Amarillo VENEZUELA -1, which is boing distributed to the farmers of this country for commercial production, is neither dent nor flint corn but rather an inter- mediate between the two, with variations toward both extremes. This intermediate type, often referred to as tropical flint, is preferred to dent corn because it is more resistant to damage by the ever-present grain weevil• Considerable difficulty has been encountered in maintaining this variety as a tropical flint. The farmers who make no selection in their corn complain that after two or three generations VENEZUELA-1 degenerates, that is, the amount of soft starch increases. Even in the Experiment Station where there has been selection for tropical flint ears during the past eight generations, the soft starch type reappears in considerable quantity at each harvest. The ears of the true flint type are scarce. In this connection it is worthy to note that the dent corn from the United States and from Argentina become extremely soft under these condi- tions and little hard starch is developed. 2. Tall Corn. In the lowlands of this country where the soil is relatively fertile nearly all the local varieties of corn are extremely tail and the ears are often six to ten feet from the ground. The improved type, VENEZUELA-1, was especially popular when introduced to the public because it was shorter than the local varieties and had a low set ear. It has been discouraging to find that each year this corn is becoming taller and the ears are farther from the ground. Mass selection for low growing plants with their corresponding low set ears has been practiced for eight generatiens with little permanent success. 3. White Corn. Corn, prepared in a multitude of ways, is the principal food of‘the people of this country. Due to custom, the people of the central part prefer white corn while those of the eastern and western parts prefer yellow corn. When the corn improvement program was initiated in 1939, emphasis was placed cn the selection of hign yielding varieties ol yellow corn with the hope that the people in the central region would take advantage of the improved seeds ana perhaps learn to like yellow corn over a period, of time, and thereby improve their diet. Luring the past two years this faint hope has been realized in certain areas in which the improved yellow corn, VENEZUELA-]., has given as much as increase in yield over tne local white varieties. But in spite of this indication that a change in custom might be possible, we have finally yielded to public pressure to develop iiaproved varieties of white corn (as a matter of fact, both white and yellov/ corn have been included in the corn improvement program since 1939, but tne hybrids and the improved varieties of white corn iiave not been publicized). The few kernels of white corn which always appear in some of the ears of the variety Maiz Amarillo VENEZUELA-1 have been used as the basis of a new variety, Maiz Blanco VENEZUELA--3. From many thousands of ears of VENEZUELA-1, several hundred ears segregating white kernels were shelled together and planted in a small field. Before pollination t-he weakest plants 535 v/ere eliminated. At the time of harvest, two kinds of ears were found: those with all of the kernels yellov; and those with some kernels white and some yellow. The yellow ears were discarded. Of the ears with both white and yellow kernels, the Less were shelled together and the seeds were placed on tables where a group of women picked out the white kernels py hand. (The white Kernels were not all pure white; some were a faint yellow). They were planted in several experiment stations and with several farmers for propagation. The harvest from these propagation plots was not completely white but is commercially acceptable. Further selection is being carried on to improve this new variety, VENEZUELA-3, but this slightly mixed type is being distributed to the farmers for commercial production. In the yield tests conducted in five different states this year, the varieties, VENEZUELA-3 and VENEZUELA-1, were nearly identical in plant type and in yield. D. G. Langham 536 • ‘;ana, B. D. On the variation Ln the rate of elongation of the coleoptile of Zea mays. Current Sci. (India) 12: 87. Mar. 1943- Beard F. C. The germination capacity of maize pollen having aberrant nuclei. Torrey Bot. Club Bui. 70: La 9-456• Sept. 194L* Bliss, C.I., and R. B. Dearborn. The efficiency of lattice squares in corn selection tests in New England and Pennsylvania. Amer. Soc. hort. Sci. Proc. 4.1: 324-342. Sept. 1942. Burr, H. S. Electrical correlates o? pure and hybrid strains of sweet corn. Proc. Natl. Acad. Sci. 29: 163—166. June 1$, a943» Gamp, L. M., E.F. Frolik, and Th. A. Kiesselbach. 1942 Nebraska official corn yioid tests. Nebr. Agr. Ext. Circ. 103, 23 PP- Lincoln, Mar. 1943• Clark, F. J. Cytoiogical and genetic studies of sterility in inbred and^ hybrid maize.. Conn. (State) Agr. Expt. Sta. Bui. 465, PP- 705-72c. New Haven, Sept. 1942. Cowan, J. R. The value of double cross hybrids involving inbreds of similar and diverse genetic origin. Sci. Agr. 23 (5): 287-296. Jan. 1943- Grim, R. F., end others. Comparative studies of commercial and station corn hybrids for maturity as determined by moisture percentages at husking. Minn. Agr. Expt. Sta. Bull. 367, 14 PP- St. Paul, Jan. r943- Doty, D. M., M. S. Bergdoll, and S. R. Miles. The chemical composition of commercial hybrid and open pollinated varieties of dent com ana its relation to soil, season, and degree of maturity. Cereal Cnem. 20 (1): 113-120. Jan. 1943. pongan, G. H. Relative photosynthetic capacity of stalks, leaf sheaths, and leaf blades in maize as measured by the contribution each makes to the development of the grain. 111. State Acad.S s. Tth»&35 (2): 42—44• Dec. 1942. Edwards, F. rr. The relation of temperature ana soil F.oisturo to the development of seealing blight of maize due to Gibberella i^.Ukuip.i and Gibberella fujj.kuroi var. subgldtianns. Linn. Soc. N.S. bales Proc. (1941) 66 (5/6): 425—439, Dec. 15, 1941. Einset, J. Chromosome length in relation to transmission irequency of raize trisones. Genetics 28: 349-364* Sept. 1943- 'Ellet, C. W. Leaf blight of corn. Phytopathology 33: 407-408. May 1943- Elliott, Charlotte. A Pythium stalk rot of corn (P. butle_rij. Jour. Agr. Res. 66 (1): 21-39- Jan. 1, 1943. Erwin, A. T. Anent the origin of sweet corn. Canning Trade 65 (30): 15-10, 20. Feb. 22, 1943. 537 vrnu Katherine. Ontogeny of the vascular bundle in Zea mays* Hilgardia w * 15: 325-308. Apr. 1943- Freeman, W. II., and others. Tests of corn hybrids and varieties at seven locations in Mississippi, 1942. Miss. Agr. Expt. 3ta. Bui. j/.•, !-> pp. State College, Jan. 1943* Haves, H. K., E. P. Murphy, and E. H. Rinke. A comparison of the actual yield of double crosses of maize with their predicted yield from single crosses. Amer. Soc. Agron. Jour. 65 (l): 60-65- Jan. 1943- Horowitz, S., and A. H. Marchioni. Herencia do la rosistencia a la langosta en el rnaiz "Amargo." Anales del Institute Fitotccmco de Santa Catalina. 2: 27-52. 1940* Horowitz, S. Nuevo gen del cuatro cromosoma de rnaiz. Anales del Institute Fitotecnico de Santa Catalina. 3: 13-20. 1941• Horowitz, S., A. H. Marchioni, and H. G% Fisher. El factor sux y el aumexito del contonido de azucar en el rnaiz para choclo. Anales del institu,o Fitotocnico de Santa Catalina 3: 37-44- 1941- Houseman, E. E., and F. E. Davis. Influence of distribution of rainfall and temperature on corn yields in western Iowa. Jour. Agr. Res. ot \±*-). 533-545- Dec. 15, 1942. Jenkins, M. T. Breeding corn for war. Seed World 52 (12): 10-11. Dec. 18, 1942. Jenkins, M. T. A new locality for teosinte in Mexico. Jour. Heredity 34: 206. 1943. Johann, Helen. Phoma torrestris in the roots of mature maize plants. Phytopathology 41: 526-528. June 1943- Jones, D. F. Growth changes associated with chromosome aberrations. Genetics 28: 78 (abstract). 1943- Jugenheimer, R. W., A. L. Clapp, and H. D- Hollembeak. Kansas corn tests, 1942. Kans. Agric. Expt. Sta. Bui. 311, 44 PP- Manhattan, Jan. 1943- Kadam, B. S. Maize genetics cooperation news letter No- 16 (194^)- Indian Jour. Genetics and Plant Breeding 2: 184-186. 1>42. Kemptori, J. H. Differential effect, of nutrient solutions on the size of various parts of maize seedlings grown in the dark. Jour. Agr. Res. 66 (5): 183-223. Mar. 1, 1943- Langham, D. G. Maize dulce Venezuela-2, una nueva ciase de maize. El Valle, D.F., Venezuela, Inst. Expt. de Agr. y Zootec. Giro. 3, 4 PP- Caracas, Dec. 1942. Langham, D. G. Venezuela-1, una seleccion de maize recomendable. El Valle, D.F., Venezuela, Inst. de Agr. y Zootec. Cir. 2, 8 pp. Caracas, Dec. 1942. 538 rindstrom, E. W. Experimental data on the problem of dominance in quantitative character inheritance in maize and tomatoes- Genetics 28: 81-82 (abstract). 194-3- Mazoti, L. B. Estudio genetic© sobre maices amilaceos de Argentina. Anales del Instituto Fitoteonico de Santa Catalina. 2: 1.7-26.1^+0. McClintock, B. Maize genetics. Carnegie Inst. Wash. Yearbook (194-1/4-2) 21: 181-186. 1942. MiHikan, C. R., and W. V. Lubbrook. Maize diseases in Victoria. Victoria Dept. Agr. Jour. 41: 207-212. Apr. 1943- Morgan, D. T., Jr. The formation of chromocenters in interkinetic nuclei ’of maize by knobs and B chromosomes. Jour. Heredity 34: 195-198. July 1943. Nevens, W. B., and G. H. Dungan. Yields of corn hybrids harvested for silage and methods to determine best uime to harvest. 111. Agr. Expt. b~-a. Bull. 494, pp. 387-4-12. Oct. 1942. Pinnell, E. L. The variability of certain quantitative characters of a double cross hybrid in corn as related to the method of combining ---- the fourth inbreds. Amer. Soc. Agrori. Jour. 35: 508-514- 1940. Peiss, F. and others. The 1942 Iowa corn yield test. Iowa Agr. Expt. Sta. Bui. P51, PP. 627-680. Ames, Feb. 1943. Rhoades, M. M. Genic induction of an inherited cytoplasm difference. Proc. Nat. Acad. Sci. Dec. 1943. Singleton, W. R. Breeding behavior of C30 a diminutive P39 mutant whose hybrids show increased vigor. Genetics 23: 89 (abstract). 1943. Sprague, G.F., and J. E. Bass. Heritable characters in maize: "accessory blade” (abstract). Iowa Acad. Sci. Proc. (194-2) 49: 256. oept,. 1 42. Sprague, G.F., and M. T. Jenkins. A comparison of synthetic varieties, multiple crosses and double crosses in corn. Jour. Amer. See. Agron. 35: 137-147. 1943- Sprague, G. F., B. Brimhall, and R. M. Hixon. Some effects of the waxy gene in corn on properties of the endosperm starch. Jour. Amer. o Agi'on. 35: 817-822. 1943- Sprague, G.F. Production of hybrV corn. Iowa Agr. Expt. Sta. 3ul. P.+.c, pp. 556-532. Ames, Sept. 1942. Sprague, G.F., and R. M. Hixon. A new starch from corn. Seed World 53 (2): 20-21. Jan. 15, 1943. Stadler, L. J-, and S. Fogel. Gene variability in maize. Genetics 28: 90-9-1 (abstract) 1943- 539 Stadler, L. J., and H. Roman. The genetic nature of X-ray and ultraviolet induced mutations affecting the gene A in maize. Genetics 28. 91 (abstract). 1913- Stringfield, G. H., R. D. Lewis, and II. L. Pfaff. Ohio corn performance tests and recommendations 1912. Ohio Agr. Expt. Sta. Spec. Cir. Go, 37 pp. Columbus, Feb. 1913• Tatum, L. A., and M. 3. Zuber. Germination of maize under adverse conditions Airier. Soc. Agron. Jour. 65 (1): 18-59. Jan. 1913. Timm, S. W., and E. 71. Lindstrom. Experimental proof of mutation in^ virulence of the bacterial wilt pathogen of maize. Genetics 28: 91 (abstract). 1913 Ullstrup, A. J. Diseases of dent corn in Indiana. Ind. Agr. Expt. Sta. Circ. 280, 20 pp. Lafayette, Jan. 1913. Wellhausen, E. J. The accuracy of incomplete block designs in varietal trials in West Virginia. Amor. Soc. Agron. Jour. 35 (lj: o6~7t. Jan. 1913. Wellhausen, E. J. Leaf blight of corn in West Virginia. Plant Dis. Rptr. 26 (23): 191-195. Dec. 15, 1912. Wiidakas, W. Comparative yield and maturity of corn hybrids. N. Dak. agr. Expt* Sta. Birao. Bui. 5 (l): 32-31- Mar. 1913- Wiidakas, W ., and W. J. Leary. 1912 hybrid corn field trials. N. Dak. Agr. Expt. Sta. Agron. Llimjo. Cir. 71, 19 PP- Fargo, Jan. 1913- Alice IS. Brown Columbia University V. SEED STOCKS PROPAGATED IN 1913 Dr. Murray and Miss Morris grew over 200 cultures and hand-pollinated approximately 1600 ears. These cultures consisted mostly of stocks that had been listed in earlier News Letters, that were in need of replenishing, or that were several years old and liaole to loss of viability. R. A. Emerson 540 MAIZE GENETICS COOPERATION NEWS LETTER 19 February 15, 1945 The data presented here are not to be used in publications without the consent of the authors. Department of Plant Breeding Cornell University Ithaca, N. Y. 541 Reports from Cooperators ................. 2 Bureau of Plant Industry and Cornell University .... 2 Bureau of Plant Industry and Purdue University *.... 4 California Institute of Technology ....»........... 5 California Institute of Technology and Cornell University............ ............................. 3 Columbia University .......... .......... 13 Connecticut Agricultural Experiment Station ....... 15 Cornell University......... .......*.... *......... 16 Florida University ..................... .......... 21 Harvard University................... ....... . 27 Minnesota University......... .................... 30 Missouri Botanical Garden •*••*••••••.»•*••••*•••••« 32 Missouri University 33 Maize Publications ..»•••.... 45 Seed Stocks Propagated in 1944 50 542 I. REPORTS FROM COOPERATORS Bureau of Plant Industry Station and Cornell University, Beltsville, Md. and Ithaca, N. Y. 1. Tetraploid maize-Tripsacum hybrids. In 1942 the ex e cm ib sr ey co , technic was utilized to obtain two hybrids of tetr a an pd l ot ie dt r ca op rl no id Tripsacum. Since these hybrids received of t wc o hr so em to ss omes from each parent it was anticipated they fe wr ot ui ll de bi ef the chromosomes comprising these sets syna b piv sa el de n tt os . i ormB ut these two hybrid plants proved to be comp T lh ee ty e ln yo t s to en rl iy l ep .r oduced no functional pollen but when used p a ar se n tt i ei n s eb ea uc kcrosses to their parents no viable seed f r wo am s th oe bm t. a inA e d variable number of bivalents were formed an t ah e mre aw ae cr ie t ia ol nw ays present from one to several multivalent complexes that could not be fully analyzed. Compared with the elaborate technic of Mangelsdorf^ R ae ne dv es a relatively simple procedure was employed to obt h ay ib nr i td hs e. s e The husks of the eershoots were opened suffic p ie er nm ti lt y a t om ixture of Tripsacum and corn pollen to be s th ie f teba ds e is n o af o outh e silks, the husks were then replaced abo sh uo to t t ha en d e «h re ld in position by the glassino earshoot b w ai gt h rr ou ib nb xe or r ceb aan ds. Approximately three weeks after pollin e am tb ir oy no s t ho ef the partly developed kernels were excisea ana i cn u lt tw uo r eo unce screw cap bottles on the sterile nutne P nlo ye md o ab iy u mR a cn m dolph and Cox for the culture of i n s emb A rm yc or st 's Io Pc ro. c K .o rU Sci. Vol. 43, 1943). As soon as , root sys s te ee md l ai nn dg loaves were formed the seedlings trans erre ° The too hybrids produced in 1942 resulted fr t oi mo n t ho ef p1 o4 l lo ia nr as -hoots of a synthetic tetraploid corn hybrid invol 5 v id ni gf ferent yellow dent lines (Stock A in accompa a n ym ii nx gt u tr ae o ef ) tetraploid Tripsacum and tetraploid com pollen i cn ae r ra y full complement of genes for colored aleuron i en .c lud Ce od r nw ith the •Tripsacum pollen because Jengclsdorf f ao nu dn d f iot eh va et s the presence of a certain number of normally acvelopi».b corn grains on the ears aided the aevel k oe pr mn ee nl ts that might result from the functioning of xripsacum p C oo ll lo er ne .d aleurone was involved to facilitate the sooara-i ..} from the non-hybrid seeds. In 1943 a further attempt was made to obtain addit h iy ob nr ai ld s for a more adequate study of their chara v ci tg eo rr io su ts i ct se .t rap °l uo ri d hybrids of commercial itoes of yellow w do er ne t s ce ol ected as the seed parents. From a total oi S8 poll 6 i8 n ai tm im oa nt su re embryos or embryo-like structures wore o cf u lt th ue rs ee d ,w er te o si tn viable and the eight seedlings obtained from them proved to be non—hybrid corn seedlings. 543 The stocks used in 1911 to repeat the cross differed from those used in the preceding two years. Those are listed as stocks B~F in the following table which summarizes the results obtained in 1912 and 1911. Stock B was a multiple recessive totraploid combina- tion of one or more recessive genes in each of the ten chromosomes {Pv-bm2, b-lg, A-cr, su, pr, y-pl, in, j, c-wx, Hg-g). Stocks C, D and E were, with respect to most of these recessives, duplex hetero- zygotes, the recessive stock having been crossed with an aB PI lg type to produce C, and AB PI R type to produce D and with the inbred 187—2 to produce E« StocK F was an Fi hybrid ox tv/o commercial yellow dent lines, one of which was 187-2. Embryos viable Non-hybrid Stock Ears i>ol. cultured hybrid seedlgs.co m seedlgs. A u 78 2 26 B 22 0 0 0 C 6 13 5 9 D 3 H 1 3 E 7 1 1 2 F 10 2 1 0 Perhaps the most interesting conclusion to be drawn from the results of these attempts in 3 different years to obtain hybrids between tetraploid corn and tetrapioid Tripsacuir. is tnat hybrids may be obtained much more readily from certain stocks than from others. Gene differences affecting crossability may be involved, or, it the suggestion of Mange^sdorf and Reeves that corn carries segments of Tripsacum chromatin is to be taken seriously the possibility that such segments wore present in the stocks which crossed most readily should bo considered. However, there were no pronounced difference^ in knob frequency in the Stocks A-F; ail had relatively iow knots. The hybrids obtained in * 1911 have not yet reached the sporocyte stage. One of the hybrids obtained in 1912 produced abun- dant tillers and has been maintained by vegetative propagation without difficultyj the other 1912 hybrid was less vigorous, produced few tillers and could not be kept alive by vegetative propagation. Ex- treme differences in the vigor of the 11 hybrids obtained from the 1911 crosses suggest that they nay differ appreciably with respect to their chromosomal configurations. 2. Trisomic stocks. The number 1 trisome has been identi- fied cytoiogically in stocks which gave trisomic ratios for bn^. All of the 10 trisomes have now been isolated and stocks of these are available in cultures known to be free of supernumerary B-type chromosomes. L. F. Randolph 544 Bureau of Plant Industry and Purdue University Boltsville, Md. and Lafayette, Ind. Inheritance jf sueceptibi.L: tv to Helminthusperium carbonum Race I. There are here submitted preliminary data on the linkage relations of the gene hm governing susceptibility to infection by H. carbonum Race I*, Earlier studies (Jour. Agri. Res. 63:331-334, 194-1.') and (Phytopathology 34: 214-222, 1944) have shown susceptibility to in- fection by H. carbonum Race I to be inherited as a monogenic reces- sive. Appropriate crosses were made by Dr. E. G. Anderson using a series of translocation stocks in which su endosperm was used as a translocation marker. The parents Pr and K6l are homozygous suscepti- ble inbred lines of normal dent corn. The F]_ material was backcrossed with pollen from double recessives (sugary susceptible plants). Kernel separations were made of the backcross progeniesy planted in the green- house and seedling inoculated at the 3-4 leaf stage. One week after inoculation disease readings were made. The data in table i definite- ly indicate that the gene hm is located on chromosome 1. In table 2 a summary is given of a four-point test involving 9 backcross progenies. Further studies are underway in which back- cross progenies x P- will be used. A series of trans- locations all involving chromosome 1, and supplied by Dr. E. G. Anderson, will also be under observation in 1945. Table 1. Segregation of seedlings in which su endosperm was used as a marker for translocations Number ^ Chi Range kernels planted Sugary Starchy Square of F1 Sug* St. Res. Sus. Res. Sus. Values "P11 suTl-Aa x Pr 1344 1149 921 317 190 912 767.0 < .01 K6l x suTl-4a 924 894 664 176 150 703 o42.0 < .01 suT2-4a x Pr 408 475 173 207 234 341 3.1 .2 — .3 K6l x suT2-4a 541 675 223 259 319 3 U 3.6 .1 - .2 suT2-4c x Pr 566 512 266 239 245 238 1.5 .3 — .5 K6l x suT2-4c 516 511 240 237 248 237 .3 .5 — .9 suTuT4-5b x Pr 458 476 199 206 230 230 .1 • 5 - .9 Kbl x suTuT4-5b 250 273 120 114 133 139 .3 .5 — .9 Pr x suT4-6a 478 495 190 205 240 221 1.3 .5 — .9 K6l x suT4-6a 443 484 187 181 255 218 3.0 .2 — .3 Pr x suTA-S 336 437 157 161 224 188 *2 .5 — .9 Pr x suT4-9a 548 545 227 219 244 249 .8 .5 — .9 K6l x suT4-9a 252 251 114 109 115 128 3.2 .2 — .3 K6l x suT4-10b 257 245 127 125 112 119 .2 .5 - .9 * Also represents kernel ratio found on ears 545 Table 2. Four-point test for the gene hm, the Fp genotype being hm + + + + br f bni2 Parental Progeny Com- Reg. Reg. Reg. Reg. Reg. Reg. No. binations 1 2 3 1 & 2 1 & 3 2 & 3 Total 1 _l 1 31 3 lil 0 2 19 43 j0 4 3 3 2 3 158 2 61 50 11 20 2 6 47 53 9 1 7 q 0 16 292 3 45 5L 3 19 2 10 40 45 7 0 8 13 0 8 259 A 46 53 11 12 2 8 33 36 4 6 10 12 2 9 244 5 58 53 8 6 1 7 46 51 4 0 3 6 1 3 247 6 47 52 12 19 3 6 55 45 6 1 12 6 5 9 278 7 53 62 13 13 1 8 29 54 3 0 7 7 2 6 258 8 73 37 4 22 0 6 29 44 7 0 7 9 0 21 259 9 45 46 5 12 3 7 29 64 6 3 3 8 1 3 235 459 438 75 134 14 60 327 435 49 15 60 73 13 78 Total 897 209 74 762 64 133 91 2230 ____ 9.4$ 3nj/o 3L.2? _ 2.9? 6.0% u.1% The indicated genetic map is: hm 18.3 br. 10.3 f 44.3 bm2 Arnold J. Ullstrup and A. M. Brunson California Institute of Technology, Pasadena, California The follov/ing tables are compiled for the benefit of those using or wanting to use the sugary and waxy series oi translocations for the study of economic or other characters in maize. The data included in tables 1 and 2 are the per cent of crossing^ovor with su or wx in the heterozygous translocation plants, the position of the break in the other chromosome, and which alleles cf Su_£U or Wx ex are present in each translocation. Tables 3 and A give a -List of ns-/ semisteriles which small test plantings have shov/n to oe lineed to su or wx. 546 Crossing Cyto- Gene over with Chro- logical Combinations su mosome position Linkage available 1 -4a 3-0 1 br-20-T~45-bm2 Su su 2-4(K-10) (2.) 2 near B (±8) Su SU 2-4(0-31) close 2 near B (±17) Su 2-4a 3.5 2 2L.2 B-T-1.5-V2T Su su 2-4C 9.2 2 V2T— 19.0-T-29.2-Ch Su su 2-4(4-29) 6.1 2 yfl— 22.3-T Su su / 4-5C 1.1 5 bm-3.5-T-15 *5-pr Su 4-5d 1.9 5 bm-2.5-T-5.5-pn Su su 4-5(X-6-77) 9.0 5 pr ±16.4 Su su 4-6a 4.5 6 6L.3 very close to Y Su su 4-6C 2. 6 very close to Y Su 4-7a close 7 7L.3 near ra and gl Su 4-Ba close 8 8L.1 T-34~nis8-j Su su 4-9(F-22) 4.2 9 c~wx-6.9-T Su su /c-wx-11.5-T 4-9a jP 9 9L.8 Su su1 2*0 (c-wx-31.0-T 4-9(A-26) close 9 not tested Su 4-10 b 4.0 10 near g Su su 4-10(B-45) close 10 T-8.8-g-R Su l,3,4,5,(B-2) close 1,3, 5 1 not tested, 3 near ts/+, 5 near bm Su su 547 Crossing Chro- Cyto- over with mo- logical Gene wx some position Linkage combinations 1-9 C 1 2 . 1 1 IS 6 P-0.8-T Wx wx l-9a 1 1* 2 1 IS, P-21.2-T~35.6-br Wx wx 2-9 b 7.5 2 2S.1 tsx-5.3-T-7.8-yJ Wx wx 3-9a 3*6 3 near ts^ Wx wx 3-9C 7.6 3 3L.1 near ts^ Wx wx 3-9b 6.8 3 lg2~7.9-T-l8.0-a! Wx wx 4-9 (F-22) 6.9 4 su-4.2-T-Tu Wx wx 4-9 b 3.1 4 4L.6 su-Tu-^13 -2 1.9-T Wx wx 5-9a 2.0 5 5L..6 bmi-pr-25-T Wx wx 5-9 (X-U-lll) near 1NX 5 (near pr) wx 6-9a 9.4 6 6S. T-12.9-Y-P1 Wx wx 6-9 b 3.8 6 near Y Wx wx 6-9 (a-66) 12 .2 6 near Y Wx wx 6-9 (X-25-78) 3*4 6 near Y Wx wx 8-9a 13.7 8 8L.2 T-30-msg-j Wx wx 9-10b 5.7 10 T-8.8-g-R Wx wx 9-10a 4.5 10 10L.9 g-R-3*2-T Wx wx Table 3. New semisteriles linked with sugary. Backcrosses with su Gene Total Crossovers Combination n-61 36 0 Su I-10 38 3 su K-17 107 3 Su su X-l-1 39 3 Su su X-2-64 36 2 Su su X-17-108 near su su X-19-5 near su su X-47-41 39 0 su X-57-31 30 1 su 548 Bc.okcrocseS with wx Gene Total Crossovers Combination, a-76 34 2 Wx F-24 96 7 Wx wx bp near wx wx X-7-39 40 3 Wx wx X-10-6 37 0 wx X-ll-73 37 5 Wx wx X-22-92 39 1 Wx v/x X-23-15S 39 5 Wx wx X-26-3 35 2 Wx wx E. G. Anderson California Institute of Technology and Cornell University Translocations and centromere positions, iranslocations are especially useful in determining the location of genes in rela- tion to the centromere and other visibly differentiated regions of the chromosome, due to the fact that their position in the chromosome can be determined cytologically and their linkage relations with known genes also can be determined. The following is a summary of available data on the relative positions of translocations and genes in the neighborhood of the centromeres in chromosomes 1 to 9 incluoi/e, with a few records for chromosome 10. These data were compiled chief- ly from Dr. Anderson's records while in residence at the California Institute of Technology for several months in 1942 and 1944. Chromosome 1. - Information on translocations in the short arm of chromosome 1 was summarized by Anderson in 1941. The gene P is about two-thirds of the distance out on the short arm. A minimum map distance from P to the centromere may be determine-! ^rom % l_9s, which is known to be located in the short arm. On the basis of 730 plants the per cent of crossing-over between P and T l-9a was found to be 21.2 ± 2.5. Thus the location of the centromere in the linkage map is 21.2 units or more to the right of P. A number of translocations in the long arm of chromosome 1 give less than 5 per cent of the crossing-over with brachytic. These are distributed from about L2 to about L6. The gene br is probaely located in the neighborhood of L3 or L4. Only 2 of the translocat i in o nt sh e long arm are definitely placed to the left of br. T l-6a was reported by Burnham and Cooper and Cooper and Burnham to be in the 549 long arm of chromosome 1 a short distance from the spindle insertion. From their diagrams and figures a position of about L2 is indicated, which is also in accord with other data. The map position, based on 75 plants, is given as 13*1 units to the left of br. T l-6b has been described by Burnham. The locus in chromosome l is given as 1.2.5# Very good linkage data involving 952 plants place the trans- location to the left of br with 3.3 per cent of crossing over. (Data by Burnham cited by Emerson, Fraser and Beadle, 1935). Those data merely show that br is between one-quarter and one-half the distance out on the long arm. The map position of the centromere must be some where between the locus of T l-9a, 21.2 units to the right of P and the locus of T l-6a, 13 units to the left of or. This is a very long region. If crossing over were equally distributed over this portion of the chromosome we might expect the centromere to be about midway between P and br. Chromosome 2. - The map location of the centromere can be rather closely delimited by a number of translocations in the interval between ts and v/. boveral of these will be considered. T 2-9b is located cytologlcnlly at 2S1 and 9L2. Linkage tests give the order definitely as B-ts-T-v^. Crossing over between the nearest genes was ts-T = 33/622 = 5.0 per cent t-v^ = 121/1528 = 7.9 per cent Since the break in chromosome 9 is knov/n to be in^the long arm (Anderson, 1938), the wx gene is carried in the 7^ chromosome. Tests of linkage relations in the homozygous translocation can be used to verify the location of the break in chromosome 2. These tests gave the following results, showing that the breax is between ts and . B - ts. = 27$ ts - vy = 55%9 or independence, wx - B - 21,3% wx - v/ , repulsion series - 5 1*5!* wx - coupling scries in 50.1$ o The wx gene is carried in the 9^ chromosome. The linkage of wx with B and its independence of v^ establish- es the break in the short arm of chromosome 2 between B, and centromere. Tne linkage of B and ts shows the break in to the right of ts. and the independence of ts. and v/ locates the break between those genes. Thus the centromere is at least 5 units to the right of v^. T 2-5a was studied by Khoades and described cytologically as in the long arm of chromosome 2 near the centromere. Linkage tests give the order as B-T-v^ with 7.3 per cent of crossing over between T and 7^. 550 T 2-10a is located at L2, with the break in chromoGome 10 well out on the long arm, 2 to 3 cross-over units to the left of The order on chromosome 2 is ts-T-v^ and the data on crossing over are as follows: ts-T - 11,4 per cent T-v^ = 6.6 per cent Linkage data in the homozygous translocations are as follows: B-ts -- 16 .+ per cent B~g - 20 per cent Since g is distal to the break in chromosome 10 the B-ts, secti chromosome 2 on of must include the centromere, i.c., the translocation must be in the long arm of chromosome 2. These data may be summarized as follows: T 2-9b ts_-5.0-T-7•9+-v^ short arm T 2-5a ts -T-7.3 -V4 long arm T 2-10a ts-ll.4-T-6.6-v4 long arm The centromere must be 5 or more cross-over units to the right of ts and 7.3 or more units to the left of V4. since there is usually oome supression of crossing over in the he”Eerozygous translocations, the total map distance of the ts-w interval is uncertain. The normal value is probably about 20 units. The centromere is probably a little closer to ts than to v^. Chromosome 3. - The summary of translocations involving chromosome 3 published by Anderson and Brink places the centromere in the general neighborhood of ts/. Since then additional data on T 2-3b has indicated that ts^ is m the long arm of chromosome 3. This translocation shows aBout 4 per cent of crossing over T h we i to hr d ve ^r . is probably B-sk-v^-T. Linkage tests in nomozygous 1 1 stocks give the following cross-over v lues. B-sk = 39/399 = 9.+$ B-y4 = 128/289 - 44.3% B-1LB4 = 495/1171 = 42.3^ ts4-lg2 = 27/135 = 20.0$ v4- ts4 = 10/59 = 17.+% These data all agree in placing the translocation beyond 34, conse- quently in the long arm of chromosome 2. The linkage of 654 with B and v/ in the homozygous translocation places the break between the centromere and ts/, and shows that it is the long arm that is involved F rom this it maybe concluded that the centromere is to the left o. ts4 , i.e., between d and ts^. 551 Chromosome A . - A number of translocations in the proximal regions of both arms of chromosome A adjacent to the centromere all show close linkage with su, usually accompanied by much suppression of crossing over. These data indicate that the centromere is in the general region of the su locus. Data on T 2-Ac place su in the short arm# This translocation is very near the centromere in the short arm of chromosome A, and is far out on the long arm of chromosome 2 between v/ and ch. Linkage data from homozygous T 2-Ac show ts5 and su to ’Be linked and su to be independent of Tu. Thus the break is to the right of su. Further data on this homozygous translocation areas follows: su-v/ = AO1/1057 = 37.9A per cent su-cn = 2.',7/525 = A7.0 per cent Tu-ch = 193/A29 - AA-9 per cent From heterozygous stocks of this translocation chromosome 2 linkage relationships and adjacent to the break were: V4-19.9A-T-29.3-ch for chromosome A: su-9.l-T-30.8-Tu The linkage of su with V4 in the homozygous translocation demonstrates that the translocation must be between su and the centromere of chromosome A. This places the centromere at least 9 units to the right of su on the linkage map. Chromosome 5. - The position of the centromere in relation to the known genes of chromosome 5 was determined very accurately by Rhoades in 1936, with the aid of a fragment of chromosome 5, which apparently consisted of the centromere and the entire short arm of the chromosome. In the metaphase of the first meiotic division in the microsporocytes the fragment formed a trivalent with the two normal number 5 chromosomes in approximately half of the cells; in the re- mainder of the cell3 it was present as an univalent that was rarely included in either daughter nucleus. From the known cytological be- havior of the fragment the expected hack cross ratio from fragment plants of the constitution Ana with a in one of the normal chromosomes was calculated to be 5A:3a or 37.5 per cent of recessives. This ratio differs sufficiently from the ordinary 1 : 1 back cross ratio of disomic inheritance so that 'with the aid of the fragment chromosome genes lo- cated in the short arm could be distinguished from those located in the long arm of chromosome 5. Another test employed by Rhoades to identify the genes in the short arm was the occurrence of fragment-carrying plants homozygous for the recessive gone in the back cross progenies of fragment plants carrying a recessive allele in one of the normal number 5 chromosomes. If the locus under consideration was in the short arm none of the 552 fragment-carrying plants would be homozygous for the recessive allele, barring rare exceptions resulting from chromatic crossing over* Utilizing these tests it was found that the A2 and bm loci were in the short arm and bt, jar, ys, vg and v ^ were in the long arm of chromosome 5. The available cytological and genetical data from translocations involving chromosome 5 confirm the findings of Rhoades relative to the position of the centromere between the bm and bt loci. Chromosome 6. - There are available six translocations record- ed cytologically at about 6L2 or 6L2.5* These are T l-6c, 2-bc, A-6a, 4,-6b, 4-6c and 6-9b. All are closely linked with Y and are definitely to the left of PI. All show a reduction of crossing over between Y and PI to 5% or less, in the heterogygous condition. Proven cross-overs with X have not as yet been obtained for study. With so much suppression of crossing over, little can be inferred as to the location of the Y locus with reference to the centromere. Translocations in the satillite or nucleolar region are located well to the left of Y» Data on 3 translocations between the centromere and the nucleolar region are too meagre to give any satisfactory evidence as to the position of the centromere. Chromosome 7. - Translocation 2-7b is located about one-fourth of the way out on the long arm of chromosome 7 and at about the same relative position on the long arm of chromosome 2. Linkage tests place it near ra, with slightly less than one pei cent of crossing over. Linkage tests in the homozygous translocation show linkage of ra. and jgl, which places the translocation to the left of ra. This is also confirmed by the linkage of B and ra (B-ra=l67/462=36.1%). Since B is in the short arm of chromosome 2 and is thus in the 2 chromosome ra must be in the translocated portion of chromosome 7. Several translocations in the short arm of chromosome 7 have been tested for linkage with ra as follows: T l-7d S4 5/231 2.2% T 2-7 c S1+ 24/376 6.4% T 5-7d Si 14/153 9.2% Chromosome 8. - The only gene Known to be loo chromosome 8 arc in the distal region of the long arm. from the data of Anderson (1939) the location of the centromere must be 30 units or more to the left of msg. Chromosome 9. - Translocation 5-9a is located in the short arm of chromosome 9 near the centromero and is about 2 cross-over units to the right of wx. This places the centromere at least two unite to the right of wx. T 3-9a in the long arm of the chromosome gave 3.6% of crossing over with wx, indicating that the centromere is probably not far beyond the minimum of 2 units. The gene v has not 553 been located definitely but is believed to be in the long ana not far from the centromere (Beadle 1932, Burnham 1931b)* Its map position io 12 units from wx. Chromosome 10. - The only chromosome 10 genes which have been tested with translocations are £ and R. Both are located far out on the long arm, apparently beyond L.6. Translocations to the left of L.3 have given from 9 to 23 per cent of crossing over with £♦ must lie at least 15 units to the left of £. 8-10a S.6 17.0 104/613 8-lQc S.l 22.8 122/535 9-10b L.l- 8.8 12/135 6-10a L.l 9.6 33/342 3-10a L.1+ 15.7 74/471 l-10a L.3 15.3 21/137 E. G. Anderson and L. F. Randolph Columbia University, New York City, Now York 1. Linkage relations of the bronze locus. F2 data suggested that bronze (bz) belonged in chromosome 9 and was located to the left, of C* Backcross data obtained this past year show that the order is C-sh-bz with bz approximately 2 cross-over units from sh. Summary of C Sh bz_ x c sh bz c sh Bz (0) (0) (1) (1) (2) (2) (1-2) (1 -2) c c C c C c c c Sh sh sh Sh Sh sh sh Sh bz Bz Bz bz Bz bz bz Bz 1396 1351 76 65 15 31 0 0 C-Sh 1,8% recombination Sh-Bz 1.6% « C-Bz 6.1% _____- , -------- -------- 554 Summary of Sh Bz X ! sh bz Sh Sh sh sh Bz bz Bz bz Total 6040 2952 54 62 2972 Sh-Bz 1.92% recombin 2* Cross sterility. A now mutant was found in 1942 showing a chlorophyll striping. No seeds were obtained from a large number of crosses in which this mutant plant was used as the female parent al- though these plants were self-compatible. Normal siblings were self- and cross-compatible. In many ways this situation is comparable to that previously reported by Demerec for crosses involving rice pop as the female parent. 3. Blotched aleurone. In the 1935 linkage summary the b ̂ lotched aleurone gene (Bh) was shown to give 26% recombination with I; no other linkages involving Bh were reported. This past summer I ob- tained data showing that Bh was close to PI. I mentioned this to Dr. Emerson and he dug up from his old records data which show the same close linkage. I was interested in the Bh locus because of the Bh-c interaction. As Emerson found out years ago seeds of A R £ Bh are not colorless but have irregular patches or blotches of color in the a leurone. In order to test the hypothesis that Bh was a gene stimulat- ing the mutability of recessive c. in the same way that affects a I made a number of crosses involving a chromosome 9 lacking the C locus. The deficient chromosome 9, obtained from McCIintocn, had lost that portion of the short arm from the terminal knob to and in- cluding the C locus. Sh was not included in th , doii'-iency. Plants carrying this deficient chromosome with the Sh allele and a normal chromosome 9 with recessive c and sh were pollinated by c. s£. Bh pollen. The Sh seeds had the C locus represented by a single recessive c. allele y/hile the sh seeds had three recessive c alleles. The two classes of seeds were examined for the grade of blotching, ihe data clearly show that seeds with one c allele have less aleurone color tnan d o seeds with three c alleles. The Sh and sh phenotypes have no effect on the degree of blotching. This dosage effect of c would seem to indicate that the Bh-c. situation is comparable to the Dt-a. M. M. Rhoades 555 Connecticut Agricultural Experiment Station New Haven, Connecticut 1* Six deviating lines, originating as mutations in long inbred strains, have been compared in the heterozygous condition with their normal and deviating homozygous parental lines. In all cases there was an increase in size of plant (height, width of leaf, width of stalk) and in yield of grain and a hastening of the time of flowering when compared to the mean of the parents. When compared to the larger or earlier parent in each case there are definite increases in yield in four cases ranging from 17 to 104. per cent. Increases in height in four cases varied from 3 to 9 per cent over the taller parent. Time of flowering was intermediate in two cases and earlier than the earlier parent in two cases. When outcrossed to unrelated normal lines and. compared to the same crosses made with the normal parent the differences are small and show significant increases for the deviating line in only one case. Due to the very dry season and poor location this trial is not as con- clusive as it may be possible to obtain. In every case except one the deviating line is less produc- tive than the line from which it originated and thus appears to be a degenerative change. A narrow leaf variation produces taller plants which flower earlier than the normal line. The stalk is more slender and has much less leaf area. This deviating line in previous years has been noticeably less productive but in the replicated yield test this last year it proved to be considerably more productive. Possibly this is due to the earlier maturity in a very dry year. If it proves to be more productive from now on it will be the first variation in in- bred corn to be better in ability to reproduce its Kind. 2. Attempts to shorten corn plants for convenience .in pollina- tion were not entirely successful. Two single crosses (Hy x L317 and Hy x 540) planted at two different times, May 27 and June 3, were bent to’ the ground and tied with binder twine to the adjoining plant on July 14. At this time the first planting was 3-4 feet and the second planting about 2 feet high. The plants were about one foot apart in the row. All of the plants had such a strong pull toward the erect position that all were injured to a certain extent by the string cutting into the stalks- Some plants ’ere completely severed below the growing point and thus committed suicide rather than oe tied downl Short plants were tied aoove the grov.'ing point. These bowed upwards between the base and place of attachment and tried to grow out of the leaf sheaths and were badly stunted. The treated plants in both plantings were shortened about 15 inches in ear height. The first planting was shortened 22 inches in average height of stalk to tip of tassel and the second planting 11 inches. The treated plants were also delayed a day or two in time of tasseling and silking. Both 556 nollen and seed production were seriously reduced by this treatment. Possibly the plants can be tied more loosely using a larger and softer cord. Care must be taken to tie the plants well below the growing point. Plants that were bent over and covered with soil straightened out and were not reduced in height or delayed in flowering. Plants dth half of each leaf cut off before flowering were not shortened in height but were so delayed in flowering that many of them never produced either tassels or earsl Plants grown, from seeds in which the embryo was cut out^ and attached to endosperms of the same or different genetic constitu- tion were kept in the greenhouse for several weeks and later se, m the field. Compared with untreated plants of the same type these plants were noticeably shortened. Since other plants grown for an equal length of time in the greenhouse wore not shortened it may be that the embryo excision had something to do with this change. D. F. Jones Cornell University, Ithaca, New fork 1. Whito-capped red pericarp. In News Letters 16 ana 1/^ (194.2 and 194.3), I presented data indicating that white-cap red peri- carp of such varieties of maise as Bloody Butcher is not a member of of the multiple allelic series at locus P as has been supposed and suggested that this color is conditioned by multiple genes as in quantitative inheritance, one or more of which .are closely linked wi h P. In Bloody Butcher whitc-cap red pericarp is associated with red cob (C-R), while in Northwestern Dent an apparently identical pericarp color is associated with white cob (C-W). Northwestern Dent alone was involved in the earlier work which had lead to the idea that white-cap red was allelic to P, and Bloody Butcher alone was involved in the results reported in recent News Letters. It became important, therefore to repeat the study with Northwestern Dent in order to determine whether the apparently idontical pericarp color of the two varieties is inherited in the same way. Results to date indicate that intensify of color of whitj-cap red of Northwestern Dent also is conditioned by multiple genes, one or more of which are linked with P. But certain complications have arisen which give the whole problem added interest not to say added perplexity. 557 For comparison with more recent data, there are here pre- sented records from News Letter 16 (1942), including Fo and backcrosses of Bloody Butcher, C-R, with colorless inbreds, W-W. Pericarp-color grade "0" is colorless and "6" is about the intensity of Bloody Butcher. Table 1. Cob P oricarp-c olor grades Mean Color 0 -- 1 - 2 - 3 - 4 - 5 - 6 Total grade c-r/w -w A 32 4 43 58 72 113 17 341 3.6 (_W 49 4 24 25 13 3 — 118 1.6 /W-W A us 6 38 41 40 37 2 212 2.7W-W ' l w 119 2 7 41 28 5 — 202 1.4 Cob color here shows approximately normal mono-genic segre- gation, but the ratios of colored to colorless are not those typical of mono-hybrids. The mean grade of pericarp color of red-cob segre- gates is materially higher than that of white-cob ones. The four possible combinations of cob color and pericarp color appear with frequencies indicating linkage. The some type of cross was repeated with F^C-R and W-W segregates from the original Bloody Butcher cross. The results are: Table 2. Cob 0 - 1 - 2 - 3 - 6 Total Mean C-R/W-W —A 5 5 17 34 39 3 103 4*0 t w 5 5 7 1 1 2 — — 30 2.0 ~ ~ / W - W { R — 1 4 30 29 9 _ 73 3.6 W-W l W 31 5 14 15 65 1 .2 Here again segregation of cob color is normal and the mean pericarp-color grade is higher for red-cob than for white-cob segregates. But one color-class, W-R, did not occur and the ratios of colored to colorless pericarp are far from those typical of mono-hybrids. 558 ! 1 White-cap red pericarp of Northwestern Dent, associated with white cob, C-W, also has now been studied. Crosses of this variety with a red-cob colorless-pericarp inbred, W-R, selfed and crossed with W-W are recorded below. Table 3. Cob 0 - 1 -■ 2 - 3 - 4 - 5 -- 6 Total Mean C-W/W-R f K 31 21 19 33 24 12 2 142 2.3(_W — 2 3 9 11 13 7 45 4.0 f i / w - w / k 83 — 1 __ — 84 .02 (_W 1 16 19 18 5 — 59 2,2 Northwestern Dent was also crossed with an F/vV-R segregate from the original cross of Bloody Butcher with W-W, ana Fp was out- crossed with an F^W-W segregate of the same original cross. The data obtained are given below. Table 4. Cob 0 - 1 - 2 - 3 - 4 - 5 -- 6 - 7 Total Moan C-W/W-R 41 24 16 27 23 26 3 2 167 2.5 f S 4 24 18 22 9 1 78 4.1 60 9 — — 69 .13 < 5 2 10 24 54 11 1 102 2,6 The two crosses behaved essentially alike. There was some departure from 3:1 and 1:1 ratios for cob color. The striking features of these records are (l) the absence of the W-W color class in Fp and the near absence of it in the out-cross to W-W, (2) the relatively few ears and low grade of the C-R class in the out-cross, and (3) the higher mean grade of white cob than of rod-cob ears in both F2 and the out-cross. Thus, in the Northwestern Dent crosses pericarp color, particularly of the higher color grades, tends to be associated with white cob rather than with red cob the reverse of that in the Bloody Butcher crosses. In short, the tendency is to maintain the parental associations of cob and pericarp colors. 559 Crosses of C-W with W-R, not involving Northwestern Dent but rather C-W and W-R segregates from the original crosses of Bloody Butcher, C-R, with W-W inbreds, have given results wholly unlike those in which Northwestern Dent was used as the C-W parent* The available data are given below. Table 5. Cob 0 - 1 - 2 - 3 - 4 ■- 5 Total Mean C-w/W-R P 15 15 17 27 20 6 100 2.4 t W 12 A 5 12 1 — 34 1.6 £UL/w-w A 20 16 20 16 ____ ____ 64 1.6 W-K (W 24 12 14 50 0.3 Here again cob color segregated normally* The striking features of those data are (1) the relatively high frequency of the W-W class— all but absent in the Northwestern Dent crosses— (2) the high frequency of the C-R class in the out-cross, and (3) the higher color grade of red-cob oars. In short the behavior of these crosses of C-W/W-R, in both Ir2 and the out-cross generations, was much less like the behavior of crosses of the same color types when C-W came from Northwestern Dent than like the cross of C-R/W-W when C-R came from Bloody Butcher. Eight F'j cultures have been grown from the three color classes, C-R, C-W, and W-R, obtained in from the cross of North- western Dent, C-W, with an inbred W-R. The results are given belo'.v. Table 6. F3 progenies *2 Cob Pericarp Cob Pericarp-color grades Mean Color grade Color 0 - 1 - 2 - 3 - 4 - 5 - 6 - 7 Total gra ie R 0 R 20 __ - , - 20 0 R 2 R — 1 7 6 3 17 2,6 R n. A 4 2 1 2 8 — — 19 2.7 J t w — — — — 11 4 1 1 17 4.5 — 20 3.0 R 4 A 3 3 1 1 10 1 1 t w 1 — 6 1 — 8 4.9 R 5 A — — 3 3 1 3 1 — 11 3.6 1 w 1 1 3 — 5 5.4 W 3 w — — 3 17 15 2 — — 37 3.8 W 6 w — — . — — 4 3 23 5 35 5.8 w 6 w — — — — 3 10 13 3 29 5.6 560 Ag in Fo, the pericarp-color grade is higher whe r ni t ah s sw oh ci it ae t et dh an wi2th red-cob; and as in F2 , the W-W cla Tr s so n de i dc a ns oe t t oh ce c uF r.2 recombination class C-R apparently bred true i f nor Ft 3 he presence of both cob and pericarp color. It is evid d ei nv te r ts he n intensities of pericarp color can be s e ile sc ot li ao tn e dw h be yn “No rthwestern Dent is involved in crosses w p ie tr hi c ca or lp orju ls et ^ as is true of Bloody Butcher crosses as reported in He s Letter 17 (194-3). From this report and earlier ones, it can be sa i in dt e tn hs ai tt y t ao ef white-cap red pericarp of such maize varieti B eu st c ah se r B la on od d yN orthwestern Dent and of their crosses wi n te hr ic ca or lp o rls ^t .r ,ai ns, is influenced by genes whose action is Like that o genes conditioning other quantitative^charact t eh ra st . so Im te of t Lh ^e -se h ig te en le os ba .r e linked with the gene for re To assume that some of tho effective genes of Blo a or dc y r Be up tr ce hs ee rn ted by ineffective alleles’in Northwestern Den t th e a nr de v -e hr as te is true of other such genes, and furth s eo rm e oo f -.t uh pe pm o -a e re ” more closely linked with the cob-color a o lf l el li et st ,l e i sh elp without the added assumption of intera i cn tte in os ni t oy f g se on me es with rod cob and of others with a ws hs iu tm ep t ci oo bn .s i Ot n m si ug ch ht be expected that an indivi i dn uv ao ll v fi rn og m B aloody Butcher would have at least some B lo oo t dy t liB cu t gc eh ne tr s w oi l th the same linkages and interaction wi in t hB l ro eo dd y c oB bu t ,.c sh er. Ouch C-V» plants might then be expected d i tf of e br ee hn at vl ey In crosses with W-R from that oi the w e Cs -t be r pn . .D ae n-n st . o It ̂ is ' not worth while at the present st t ao g eg o o fi n tt ho e f -u -r act th .,e r detail about this complex and somewh T ah te hp ar zi yn c hi yp pa ol t ht eh si in g to be said in its favor is tlet it seems amenable to experimental genetic test, 2. Linkage of 4-row ears. Some years su al gt os , s I ug og be ts at ii nn eg d t rh ea -t a gene for the 4-row type of ear 6 i sw e il nl ct ho r ot mh oe s or mi eg ht of PI. Four-row cultures were, therefor w ei ,t h c r8 o- sr so ew d translocation 6-10a. Y z and % were al B sa oc k ic nr vo os s v ep r .o genies were grovm last summer, ihe c ri ee nc .y as o mf a r4 - er ow ̂plants as has been observed frequently be i in og r ew i it nh dt ohi ls - character. PYom a total of 295 plants of the bac t kh co r of so sl ,l owing per cents of recombination were found. Y-Pl 29.5 Y— 4-row 41.7 Pl-T 34.2 PI— 4-row 44*7 Y-T 49.5 T— 4-row 51.2 From these results it is clear that, if a gene for c o tn hd ei t 4i o rn o wi s in chromosome 6, its locus is to be sought to tne -el of Y rather than to the right of PI. R. A. Emerson 561 3. Among the seed stocks belonging to the late Dr, A* 0. Fraser were several noted as "segregating for w and 1." Seed from a few of those cultures was planted in the greenhouse for student use and they were found, without exception, to be segregating for a dwarf as well as for w or 1. The dwarf was later identified as pigmy and the white seedling as wp. Lebedeff, News Letter of March 6, 1938, reported A.8$ recombination between w and px, assuming one £ EX, none of which were actually found. Among 413 seedlings we likewise found no w px plants, further indicating the close linkage between these loci. ±t + py w + w py Total + py_ 212 98 103 0 U 3 w + w - py 10.1 % (assuming 1 w px) The origin of the luteus in this material is unknown. There is no record of outcrossing and, so far as we can determine, it first appeared in S/ of the cross +/w x w/w.9 -•Tsatever luteus ^dis may be, it is also linked with pigmy, as indicated by the following data. ++ + py 1 + 1 py- Total + py - 635 253 292 2 1182 1 + lx - px 9*2 % E. T. Bullard and R. L. Cushing Florida Agricultural Experiment Station, Gainesville, Florida Heterosis, grain yield. For homozygous parents and linear interaction of non-allelic genes, in the notation ot Fisher et al Genetics 17:107, 1932, d is (AA-aa)/2, h is the deviation of aA from the midpoint between aa and AA, Pp — 2njd + R F, = n(d + h) + R Bp - i n ( d + h) + npd + R P2 - 2n2d + R F2 = n(d + l h ) + R B2 = | n ( d + h) + n2d + R P = 2nd +2R F — 2nd + 3 /2nh +2R B = 2nd ■+■ nh +2R 562 0 is the phenotype, n is number loci heterozygous in Fp , K is the least homozygote available by segregation# Analysis of data Maize yield Tomato, Powers^ Neai!- Lindsti'om** Danmark :> c Red Current Johannis.x Red C Height Fruit wt. Fruit wt. Estimates of 2nh (All records per cent of Fp) a u - F p U3.1 136.a 76.0 + 7.2 + 36.0 (2Fx-P) 124.4 127*6 58.5 - 751*7 - 625*1 2(2Fr B) 113.2- 62.8 - 241.6 - 228.8 2(2F2-P) 130.3 118 41.0 -1510.6 -1486.3 4/3(F-P) 126.4 124*5 52.6 -1004.7 - 845*0 4(F-B) 89.6 49*6 - 490.4 - 493.6 2(B-P) 142.0 54*2 -1261.8 -1021.5 Mean 2nh 132.3 121.7 56.4 - 750.5 - 666.3 (F2-|B) - 5.9 - 3.3 - 67.5 - 67.3 P 75.6 72*4 141*5 950.7 836.6 1J.A.S.A 2. . 27:666, 1935. Proc. 7 Int. G.C# ^J.A, Res# 63:119, 1911* The close agreement of Neal’s and Lindstrom’s data in tne above analysis seems to indicate strongly that grain yield is a func t -ion of heterozygosis. For any locus, (aA-aa) - (AA-aa) - (h / +d2 jd -( -h +d)7 = 2h. The interval from the least homozygote to the he z ty ep ro ot -e minus the interval from the heterozygote to the top homo i zs y g2 oh t e for one locus or 2nh for n loci, if h and d values are essential- ly the same for all loci. For all values of h or h/d (any degree of dominance) the es 7 timates of 2nh (table) are a homogenous set, except for non-genet f il cu ctuations. Heterogeneity indicates interaction oi non-alleles. The three quantities, (P = 2nd+2R)>(Fl = nh+nd+R)>2nh m l ui se t in that or the reverse order with each interval in any case equa t lo t/n(h-d)-i7* If h=d (dominance complete) the intervals a t ri em at ee ss - ol R. On that assumption the mean estimate o: n for -he too m aize records is minus 26.5S&1. If R cannot be negative the es mt ii nm ia mt ue m of R equal zero provides the minimum estimate oi h equal Uf The top homozygote is (P-R)- For these records it cannot be estimated larger than 74$Fq if negative R is to be avoided. 563 The data on tomato weight and estimates of 2nh from m ta hy e ms eem to suggest a complication of interactions, although e w ”e °ts of 2nh are quite similar. It is proposed to separat f er o am l la en ly i I c r f e gular nont -o a llelic interaction graphically, ihe pop inlf t i s IF a P p, t and Pp are plotted with the scale Bt of ne t t he 0 axia sc t bu ea il n gd ita anil on the x axis that of allelic b a ul tl e nl oi c n oi nn -teraction. Lay off a wide interval from Pp to P2 x o na x ti hs e. Trial positions of Fp may then be take t nw e we in t hF p F 2a n md i dt wh ae y m be ea -n of parents and each teckcross midway t fh re o mr e Fc pu r tr oe nt parent. The best trial position of FI should be f 2r (o *m £ Ft 2h >e mean of parents in the direction indicated by the data, F i oa in nd e e Fp have the same gene number and their compa l re ia s- ot n a wf if le lc te ed by non-allelic interaction. If the fc p d lo o tn to et d s oe oe im n tt oo lie on a smooth curve Fp is to be shifted right or d eft with F? and backcross shifts being J of the Fp shift t e us nt t if li t t to a smooth curve is obtained. The curve presum s ae bn lt ys rer pe rg eu -lar non-allelic interaction or regular interactio e nn v wi ir to hn ment. Allelic interaction is evident in the 7 estimates o 2nh which should be a uniform set. In this way, close fits to smooth curves were obtained wi P to hw er's data on the crosses Danmark x Red Current and Johann x i sR fe od u rC urrent with F\s just slightly to the right of the paren m ti ad lp oint towards heavier fruit. The curves lie between 0 = kx3 and 0 - b* over most of the range. Both agree closely with the hypoth o ef s iv se ry slight dominance of heavier fruit ana strong, a ct ri uo sn o af non-alleles. The interaction may of course be lit t th la en mt oh re e cubic relation of weight or volume to linear dimension. A slightly poorer fit was obtained for Johannisfeur x Bonny B est but the same dominance bias and interaction is evident t .w o Tr he ec ords on Danmark x Johannisfour did not provide c s oo nl su it si to en ns , perhaps because the parents are too close together. d if Tf hi ac tu lty would always appear with yield records on inored ma z . Complementary interaction is not regular in the above sense. It might become evident in the (F2 a -b |e B)r ra ct oi mo pn as r if sr oo nm ar ne dg u il na r interaction in the ateve graphical analys^. With 2-factor interaction, F2 is 9/16 and is 8/16 01 f tr ho em inI tP e rt o Fp ; both are 8/l6 -without interaction, t e tv iei rd ee n ic se no of complementary interaction as a factor ot hete m ra oi sz ie s y 0i eld or of tomato plant height. There seems to be f o nr o c eo vm ip dl ee nm ce en tary interaction for tomato weight except in the J co rh oa sn sn isfeur x Bonny Best. If the curve for that cross by i s ne pg ll oe tc tt ei dn g the F2 to obtain the best fit with Fp and back t ch re o sF sp e s deviation from the curve is largo and positive which a d i yc ate complementary interaction for heavier fruit. Pl o or t tl io ng g 0 J ym Pi ght bring the complementary interaction out more cleaily. 564 The reader should be warned that application of the above graphical analysis to data involving little or no non-allelic inter- action and strong interaction of alleles as in tomato plant height may produce a straight line with the 6 values spaced the same on both axes or a smooth curve through P]_, Bp, F/2, B2 and P2« In the latter event the six values will agree with the hypothesis of no allelic in- teraction on the x axis. The factor of curvature here is h. I do not now have the function. For linear interaction of non-alleles, theoretical re^re jsioriw in Fp &nd backcross of 0 on x (gene number) are: p0. $ -hx̂ * + (2n-l)dx + 2nhx + R, d0/dx - d + (2n-_2x) h ’ 2n-*l 2n'L p Bn; 0 ~ nd. + (r>-?nb)hy +■ 2n^h + R, d0/dx - d t (n-invyh n is the number of loci heterozygous in Fp; nb is the number of n loci fixed AA in the recurrent parent. These equations seem to be mainly useful for the solution of theoretical problems. For example, the backcross distribution is not skewed by any degree of dominance even though the recurren parent is fixed Aa at ail n loci, (nb - n). The slope is then (d-hj or zero if h = d. If h>d the slope is negative — 0 decreases as the number of plus genes increases. If nb is zero the slope is (d+h) positive unless h is negative and greater than d. Fo regression is a second degree parabola with slope - ̂ •uncq tion of -2hx. The F2 distribution is skewed by dominance. The xamili c ua rs e (h - d) involves the left branch of the parabola from (Q,R) ris- ing with decreasing slope to the vertex at (x = 2n-i), ̂then dropping slightly to (x = 2n). This function may be employed with the normal frequency table to construct a theoretical distribution for any num. r of loci and any degree of dominance to show that maximum skewness is reached when h = d; and that skewness then decreases with increasing h . The demonstration is facilitated by working with one pair of ?enes. Thus if A'A' equals AA, and A '«A. ^is some ag-r-ea—ter -v-al-u-e., d is ze h is r .. r o andela 2 ,t i iv Ae ll .y v large. The F , (iA'A» + £AA) becomes ($A'A ,AA + fA T h ai ;s . distribution or the product of any number of such distributions is symmetrical. If d is now allowed to -bake increasing oosi ivo- values, skewness increases up to h - d. East’s alleles of divergen function would not intensify skewness of F2# The conclusion of h>d fur maize yield is supported^by failure of mass and ear row selection, by failure of synthetic com- binations of selected inbreds, by superiority of hybrids of inbreds 565 of diverse origin, and by the success of modern maize breeding itself. If h is not greater than d, mass or ear row selection will probably continue to surpass present maize breeding technic, because of more frequent recurrence of selection. But if h>d, present technic is the only method so far tried which should effect appreciable improvement. No degree of allelic interaction will confuse selection among Fp hybrids of homozygous lines. However, selection favoring the hetero- zygote loses efficiency rapidly. It is questionable if the expectation of continuing success with present technic can be supported in Mendelian theory. Selection may be measured by the deviation of the mean of a selected group from the original mean in terms of the standard de- viation of the original. Thus "student" noted selection effects of ^ 12 and 7 sigma for high and low oil in the Illinois experiments. If the selected group may be represented by a tail of the rorraal area cut off above x = t, and the mean of the tail is s; s - (ordinate at t)/(area beyond t), or (Pt). Then l/Pt is the number of individuals from which selection of the top one may be expected to effect a se- lection differential of the given value of s. The highest value of s calculable from a 15-place table of areas and ordinates of the no1̂ 1 curve, (W.P.A. City of New York) is 8, for which 1/P-t is 222,222,000, 000,000* This is roughly 2000 times the number of maize plants grown in the world in one season. That the low oil result ( 5 = 7 ) might have been obtained by selection among 400,000,000 homozygous lines^ is plausible. The high oil result (s - 12) is 4 billion million times as difficult. Selection of the top 10 from 26 provides an s of^one in the absence of gene interaction and environmental effects. Eight ̂ recurrences of such selection will effect an s value of 8 if variability is maintained as it was in the selection for oil. A total of 208^ plants is required. From this viewpoint the oil selection results do not seem improbable as the work was done; they do seem very improbable in the face of much inbreeding. The s value of the top one of 11, 185 singlecrosses from at least 150 inbred lines is about 4* This might be a yield increase of about 40% over original stock. The genetic variance of single- crosses is the same as for single plants of original crossbred stock. Sigma in this case is then 10% of the original mean yield. This seems a fair estimate of the present Florida situation. The problem now is how much effort will be required for further gains. If each cycle of inbreeding must begin at the same level as the first, as indicated by the yield of synthetic combinations of selected lines and nearly all other available evidence, it will be necessary to identify the best single cross among 1,300,000 from 1600 homozygous lines to effect a further improvement of 10%. Gaining 10% again beyond that will be truly difficult, even though the genetic variation may remain unim- paired in the process as suggested by oil selection results. 566 A breeding technic has been proposed to deal with the case h>d, Hull, Recurrent delection for Specific Combining Ability in Corn, J.A,S.A, in press. The method is recurrent selection in a crossbred lot for combining ability with a specific homozygous line. Selection is among testcrosses of single plants of the crossbred lot to the homozygous tester line. For any locus heterozygous in the crossbred lot and aa in the tester the testcrosses are: aa, (aa+aA)/2, and aA, or if the tester is AA they are: aA, (aA+AA)/2, and AA. The three testcrosses are separated by equal intervals, (d+h)/2 in the first case and (d-h)/2 in the second. The essential point is that the three values are equally spaced as would be the three genotypes in a cross- bred population without dominance. This type of selection avoids the confusion of dominance or allelic interaction even though h>d. The price is some loss of variance. It also allows maximum frequency oi recurrence of selection. Maximum frequency of recurrence with respect to resistance to insects and diseases as well as to yield and any other desirable characters would seem to be obtained by simultaneous selec- tion. Tomato weight and height have been included lor contrast with maize yield. Estimates of 2nh involving (-B) are smaller than those involving (-P) for both maize yield and tomato weight. B values might suffer less distortion from non-allelic interaction than P values since the former are nearer the center. The slightly excessive value of B in Lindstrom's data may indicate nothing more than a little heterozygosity remaining in the parent lines. Strong allelic inter- action is indicated for maize yield. Tomato weight records indicate very slight allelic interaction but strong non-allolic interaction. Both the maize yield and tomato weight situations seem improbable. If the tomato weight interaction is the cubic relation of volume to linear dimension, why does not this function appear in the relations of aa, aA and AA at one locus? Why would it not appear in the maize yield between non-allels? Why does h>d appear only in grain yield of maizej not in components, o,g. ear length and diameter, plant height, stalk diameter etc.? Tomato height in Fp exceeds the greater parent but not the sum of parents (P). There is no evidence here of h)d and slight evidence of non-allelic interaction. The enormous selection intensities available by properly controlled recurrent selection provide a tool for investigation of physiologies 1 limits, limits of recombination, and perhaps detection of aggregates of natural or induced mutations in a group of numerous small genes. Appendix - January 10, 19A5* Hayes et al, J.A.S.A. 36:998, 194A-J data on synthetic, mean of parent lines and mean Fp • From Fp minus synthetic the estimate of 2nh is 160$ Fl * The (2Fl - P) estimate of 2nh is 127$ Fp . If h - d, and K = 0, then Fp = 2nh. Decline from Fp to Fp or synthetic is 2nh/2N, where N is number of lines. On the foregoing assumptions, expected decline of Hayes1 synthetic is 100/16 or 6.25 % Fp . If R is 20 % Fp , expected decline of synthetic is 5 $Fp, 567 The actual decline of 10% Fi, may be evidence of h>d, non-a i ln lt ee lr ia cc tion, or R<0. Taking R = 0, no interaction, then h - id for the F']_ - synthetic comparison, and h - 1.7Ad for (2Fi - P). Kiesselbach, J.A.5.A. 22:611, 1930; F2 and F3 of 21 single- crosses, h = 1.98d, Richey et al, J.A.S.A. 26:196, 1931; F2 10 double crosses, h = 1.55d. Neal, loc. cit., F2 10 double crosses, h = 1.72d. If R is some positive value all of the above estimates of h must be revised upward. Fred H* Hull Harvard University, Cambridge, IJIass. 1. Pod corn. The sterility of homozygou l sa rg pe ol dy cd ou re n t io s an excessive vegetative proliferation which may t v aa kr ei ous forms. Ts.5 is an important modifier to Tu; it u bn rd ie nr g s " Tc uo ntrol” and prevents some of the^unrestrained proliferation which characterizes Tu under some conditions. Tu can also be brought under control by various uniden g te ine fs i edin the modifier complex. It can be assumed that Tu is a f rm eo qn us et nr to lu ys character because it is the product of the "wild s "u pe gr ei nm ep osed upon modern varieties which lack the modifie w ri sl d w hm ia ci hz e i nm ust have kept the character under control. I t fi o tn h ii ss as so su un md p -then modifiers of Tu should be particularly i n a bp ur ni dm ai nt ti ve varieties of maize. The nearest approach to ’’pri m ma ii tz ie v ew hich we have so far discovered is the maize o I fn d ti ha en s G uo af r aP na yr aguay. When this is crossed with Tu and r te hep ea ht ye bd rl iy d backcrossed to Guarany, the glumes of the Tu tu a pr le a nd te sc idedly reduced. Other stocks are now being tested :or their modifier complexes with regard to Tu. We now have a homozygous true-breeding pod com. Tu p l Ta un ts with both staminate and pistillate fertility were y fe oa ur ns d a sg oo m eb ut such plants are very difficult to self beca l uo sn eg oi fn t te >r ev al between silking and anthesis. Selling, however, has finally been accomplished. The hybrid of pod corn and Guarany mentioned above has un e -xpectedly furnished a most striking demonstration of the^real o f n at th ue r ee ar of maize. Under certain conditions Guar t ae nn yd e mn ac iy z et o h ap sr o ad uce a partially indeterminate ear, which once pr i on g rub ne yond the husks elongates considerably. Tu accentuates this 568 tendency, 'During the'pastjrear we have obtained ears a t w ht ih ce h b aa rs ee nb ou rt m ae ln ormously elongated at the tip* T s hh io sw s " st th ra et t ct hh ie n ge ar ̂ of maize is fundamentally a simple spike o wf its hp ik pe al ie rt ss in whorls at the nodes of the rachis. 2* Maize-teosinte crosses* Studies of the m a gi ez ne e- tt ie co ss in oft e crosses have been greatly facilitated b o yf ta h es t do ec vk e lw oi pt mh e na marker gene on each of nine chromosomes, ten th 1e 1 other parent is pr. (bm2 !&. a su Pr Y/x has 1 b E2e ie n E. ) in Tb hr ie sd sa tn od c ki s uniform. Needless to say it t h ia st wm eo as kt , o sf o t wh ee a kp lants are barren and many do no d ti ff si hc edu lt p olas l eni ,t is b u to maintain the stock is extremely i vm ap la ur at bs l ec ,o ns ii td erable vigor to its crosses and it perm g ia tt so r tht eo mco vn et sr to il nine of the ten chromosomes in a single crons. This stock was crossed with two varieti D eu sr an og i o ta en od s iN no tb eo ,game. F2 results are shown in th I en at che c oN mo pb ao ng ya im ne g c tr ao os ls u .the nine marked chromosomes segr l ey g ao tf e e ia nc dh e po et nh de er n ta -s would be expected if no tra c nh sr lo om co as to im oe ns s , or so tt ih ce kr y complicating factors are involved. cro Is ns tt hh ee r De u ra ar ne g ot wo significant deviations, one m li nk ta hg ee db ie rt ew ce te in o n Su o and J and another indicating " W rx e pa un ld s ioGl n* bT eh te wr ee e n are additional deviations approaching statis s ti ig cn ai lf icance in the Durango cross. In addition to the nine marker genes c tr ho es s pe ls a nw te sr e i ns c bo or te hd for _ five characteristics, in which d mi af if ze er . a naO n te e oo sf i nt th ee se, a red spot at the base o D fs , t hi es sa tl as mo i nf ao tu en d g li un m es so ,me maize varieties, particular a ln yd Si os utn ho t . or ne eg ra ir cd ae n d as an important character f d ri of mf e tr he e;n t si at ni n pg o im na iz oe and teosinte. The remaining fo i un rv o al rv ee d chin a rai cn tt ee rr ss pecific differences. They are (with the teosinte characters listed first): 1. Tr Two-ranked vs. many-ranked ear or central spike* 2. Pd Single vs. paired spikelets. 3. Sd Strong vs. weak response to length of day* g7 S. (Glume Score) Prominent horny glumes vs. inconspicu- ous wenTbranous glumes. Langham's symbols for the first three characteristics a t rh ee uc sh ea dr a ac lt te hr os u gi hn volved did not prove to be simple t h me oi nr o ,i an ch te ori nt aa ln c ie n in these crosses. All of these c l hi an rk aa cg te e rw si t sh h oe wa ec h other and all but the second showed linkage, o wn ie or more of the nine marker genes. 3. Chromosome segments from Florida teosinte. Th of e c sh er go mm ea ntt si n or blocks of genes which distinguish a Fn ld o rm ia di aze th ea ov se i ntb ee en transferred by repeated backcr in ob sr se md g s tt or a ai n u no if l om ra mi ze. Two of these have now been n i cn re o- sg se en de wm iu tl ht i tp hl ee tester stock previously mentioned and backcross 569 to the multiple recessive. Here we are studying only the dominant effects of the chromatin segments from teosinte. One of these segments proved to be linked with A on the third chromosome the other with Su on the fourth. In both cases the segments are somewhere near the center of the chromosome, the segment on the fourth includes the Su locus, the segment on the third shows approximately 2% crossing over with A, which is known to be near the end of the chromosome. Both segments have the same kinds of effects. Both reduce the number of rows of grain, the size of the seed and affect the development of the. pistillate glume structure. The segment on the third chromosome is usually inherited intact but that on the fourth is frequently broken as a result of crossing over. Parts of the segment have the same general effects as the entire segment, but in a smaller degree. It is quite possible that the problem of inheritance of row number in maize is complicated by small .segments of this kind original- ly derived from Tripsacum through admixture with teosinte# Trie crosses of Nobogame and Durango teosinte previously mentioned showed ohat genes involved in the difference between the two—ranked and the many— ranked condition occur on at least seven of the nine chromosomes tested. These are probably the same kind of genes which account for differences in number of rows of grain in some varieties of maize. Summary of Linkages in Toosintj Crosses + = Linkage I = Indication of Linkage - - Independent Inheritance * = Deviation in Direction of Repulsion P, C. Mangelsdorf 570 Minnesota University, University Farm, St, Paul, Minnesota 1, Glossies, Glossy S-2 (one of Stadler's mutants) i t sh e same as gl&, leaving gl G-l and gl S-3 which are not completely tested. 2. White Cap. Additional backcross data show linkage be- tween Wf. and Ti-9b (31.3# recomb, in 208 plants); Wc and Tp-9c (26.0# in 127 plants) and new data show no linkage with Tp-lOa (H9 plan Th te s )b .r eaks in chromosome 1 are: .6 long arm, o short arm, and «4(- l )o ng arm respectively. The breaks in chromosome 9 ir the first i n tt we or changes are at .5 long arm and .2 long arn_respectively. T d ha et sa e indicate chromosome 1 is not the one carrying white cap. a pr v ei -ous test with 9-.10a (break at .3 long arm of 9) had shown no p t oi sv ie - evidence of linkage from which it was concluded that W c _h r io sm o is no me 1 (194k news letter). Closer examination of these sh do aw ts a 35.4#±S.E.%1# recombination in one culture, independence s ie nc o an d, while the combined results do not deviate significantly xro 5 m0 #. In a backcross linkage test on 190 plants there was no linkage b etween Wc and P. In the same culture f was segregating 3:1 w i ind ti hc a nt oi on of linkage. Wc, therefore, is probably not in chr o on me o, s oh ma et in chromosome 9* If so it is probably in the long arm s a i nt ce es t with waxy showed no linkage (1944 news letter). 3, Midcob color. Some evidence of linkage between red mi c do -b color and yellow endosperm was obtained, although the we rr ee s uc lo tm sp licated by the presence of both W£ and pale yellow endosper C me .r tain cultures segregate clearly 3 red: 1 colorless midcob; others show an excess of the colorless midcob class* 4. Miscellaneous. The character brown midrib-3, bm̂ c ,l o is se ly linxed with sugary-1. F2 repulsion data were: 111 Su Bm, 63 Su bm, 57 su Bm. Vivipary-5 (VP5), reported by Lebedeff (coop, l 1 e9 t4 t0 er 0f March 5, , page 14) as closely linked with yellow (probably Y) is not linked with the Y^in chromosome 6; since vp.5 and msj_ segregate independently. On ears segregating 9 yellow : 7 white or pale yello vp wp , showed about 1% of recombination with yellow. Another vivipary from C.M. Woodworth 'which has net been tested against vp^ shows close linkage with yellow on ears segr^g^tin^ 3 yellow : 1 white. Before the ears had dried in 'the field, viviparous seedlings from both sources were transferred to soil in the greenhouse• In axl cases they proved to be albinos. Although many of these ha p da l se h og wr ne e sn o mec olor underneath the husks, this color soon diseappeared. 571 Piebald-5 (pbO was reported by Lobe l de et ft fe r i nt o t hb ee cl ai mn ek e nd e ww si th Y and PI. This is co c nh fo iw rs m ec dl o bs ye al i tn ok sa tg e w hw ii ct hh mg!, and also by the independent segregation of pb.5 and VP5* I have been unable to identify the zg3 character o or bi tg ai in na el dl y as Co 306-1 (x) - A B pi Y zg^. 5. Partial sterility studies. O p no el l ce an s ea b wo ir tt hi o an b oa un td 7a 5 $ring of 8 chromosomes (originated by x- t rr ae yatment of a homozygous 5-7 inter M cr h. a nL ga ez ar sto o ca ks ) in wv ao sl nv ^ing t c ehr o fm ro os mo mes 1,5, c 6r o as ns de s 7 .o f In no r nm ea wl dx 75$ sterile plants, t s ht ee r oi fl fe s: ps re im ni gs t ie nr ci ll ue d t en do r 7m 5a %l ::273:71:181. Six • p dl ia fn ft es r ed ne tr i sv ee md i sf tr eo rm i lt eh e ring-of-8 wore sho r wi nn g b yo f U h im c th or o hm ao vs eo m ae s s io n ge -o f which was number one, while in no 6 w ca a.s , enumber involved* A stock homozygous for the interchanges invo - l8 ved ir ni n tg h- eo f (1-5-6-7) has been established. 6. Chromosome disjunction. In an abstract e t (v R- el cG oA rA d s G enU et) id ci ^t was reported t a h° ap tl a cn ht r omosome disjunf co tr i onin t ie nrchange T5-6c was ma t rh ke e dp lo ys i Rt ai no gn e o df wt hh ee n chromosome 5 centromere c e wn at se r s ho if f tt eh de nc er ao rs es r b ty h et he presence of a h 5 oc mh or zo ym go os uo sm e i nve. rsiI ot n w ia ns also reported that th o eb s ae mr ov ue nd t c or fo s cs yi ton lg o- ,o ver when the inversion d we ap se n hd oi tn eg r oo zn . w oh ue st h we ar s t dh e f fi nversion was pre c sh erom 5 nt o is no m te h e io nr t ei rn c ht ah ne g en on-interchanged 5. Cyt c oo ln of gi ig cu ar la lt yi on ths e i pn a lt he gt wo cases should be p so is ms ii lb al re . th Ia tt ws ao sme t ha od ud fi cht ional change might have accomp c ar no is es di n tg h- eo ver by which the inv c eh ra sn ig oe nd wc ah sr o im no ts rome 5. oduced Accor fdi *n .g oll ly C wa i np gropha h so em o sz ty ug do yu s o f st to hc ek s . oh la is o b ie ne gn ma 5 de:6 inversioT n - in c cp hl ru os m oi sn ov me er si 5 o Tn. 5- 6CF ,o r at nu dn ately one of th 5 e ora en ad k si n i nT t-6 heC ^w eas r si in oa n heavy chromome i rn e a r er ge ig oi no ,n ww hi it lh e s tm ha el l s ec °h °r "o dm osomes. Positions o m fe n bt r ec ao ku al gd e b ae n dc l re ea ar rl ry a nr ge ec ognized. The stock combin a ip np ge ar oe cd n t ao ,h 0a ve the exact morphology exp c er co ts es di .n ^g To hv ee r d im fe ln ®tio ^ne ed d a “bo ve appear to result iron some Chas. R. Burnham assisted by Gertrud Stanton 572 Missouri Botanical Garden St# Louis, Missouri Maize in Mexico. Maize in Mexico may ultimately be of practical importance to the U# S* corn belt because it constitutes such a reservoir of genic variability# We may also find that we must study Mexican varieties in order to understand our own, since our ultimately came from the south. This will be rather difficult since the whole pattern of variation in Mexican maize is so different and so much more complex than that in the U#S* The over-all morphological diversity in the maize of a single Mexican town may be as great as in all of the U.S., yet in another Mexican region 300 miles away the varieties may be entirely different but quite as varied# These regional differences are due in part to the great differences in altitude, temperature, rainfall, and growing season which characterize Mexican agriculture* During my six months ir* Mexico I attempted to make a reason- ably complete survey of the regions around Guadalajara (Jalisco, western Mexico) and Mexico City, with scattering collections through the intervening area. A random sample of 25 ears was taken from each field or corn crib and 15 measurements were made on each ear. A fo ; collections have been examined cytologically for knob number and tested genetically for c_, r, and pr. The following generalizations are already established. 1. Maize of western Mexico# In spite of much variation in color, row number, and kernel size, the maize of western Mexico i~ prevailingly long and slender-eared, tapering somewhat to the base an long and irregularly to the apex. Its husks are so tight that there are usually conspicuous striations running lengthwise of the ear. The row number is commonly B to 12, the kernels are frequently broad, seldom pointed, and the denting is slight or none. The plants are strong-rooted and stiff stalked. Chromosome knob numbers are high (10 or more) and the knobs are large# The recessive genes rj c_, and pr are common. 2. Maize of the Mexico City Region# The maize' of this region is prevailingly short-eared and sharply and regularly tapering to the apex* Row numbers are usually above 12, the kernels are mere or less pointed and are fre mently strongly dented. Chromosome knobs are 0 or a very few. The plants are shallow rooted, the tasselbranches few in number and the leaves broad* In the intervening, area between Mexico Cityjind Jalisco an intermediate and variable type is commonly grown. This is particu- larly true of the Mexican corn belt (the "Bajio")* centered about the state of Guanajuato. A few outstanding varieties have wide distribution and deserve special attention• 573 1, Maiz dulce, the sweet corn of western Mexico is in general unlike the corn of that region and shows striking similarities to similar sweet varieties in highland South America, Dr, Kelly and I have published a detailed report on it, (Ann, Mo, Bot, Sard, 1943)• 2, Cachuazintle. a large kernelled white, flour corn grown in the region around Mexico City and southward* Its plant type is strikingly unlike the other maize of that region. It is "popped” by cooking in rapidly boiling water* 3. "Elote" corns with colored aleurone* Throughout all those regions varieties with colored alourone (both Pr and jor) are almost universally grown. They are said to be sweeter than the other varieties and are favored for green corn on the cob (elote) and parched cornmeal (pinole). Some of them have fine wrinkles and look as though they might carry su and an inhibitor. 4. Popcorns. There are at least 3 popcorns in Mexico if we include cachuazintle under that name. The other two are morphologi- cally very different from each other in everything but popping ability. They are: Maiz reventador, the Jalisoui variety for which I have recently (Ann. Mo. Bot. Gard. 1944) published a detailed report and the rice pops of Toluca and other towns near Mexico City. The latter are similar to the semi-pointed dent corns of the same region in plant and tassel characters .and are grown inter-mixed with them. Edgar Anderson Missouri University, Columbus, Missouri 1. Gamete Selection in Cjrn Breeding. The method of corn improvement commonly known as "selection in self-fertilized lines" has been remarkably effective in the development of types of corn far superior to any previously existing variety in yield and in other agronomic characters of practical value. The general experience of co m breeders and the results of the experimental studies of breeding methods which they have made indicate that, if this job were to be done over, it would be possible to make comparable advances at a much smaller cost in time and labor. The chief results of the method experiments, as related to yield improvement, amy be summarized as follows: (l) Visual selection for yield is practically ineffective. The extent to which a plant of given genotype will contribute to yield in hybrids can only be determined by yield testing of its hybrid progeny. The factor limiting the scope of breeding operations is the number of items which may be adequately tested for yield# 574 (2) The combining value of a given genotype varies consider- ably in combinations with different genotypes. General combining value may be tested effectively in practice by crosses on mixed populations. (3) The inheritance of yield genotype is in general in agreement with expectation based on the hypothesis of complementary dominant favorable factors. (4) There is little or no advance in yield genotype in the course of inbreeding and selection as ordinarily practiced in the production of inbred lines. This fact, convincingly demonstrated by Jenkins, is the basis for current attempts to improve the efficiency of the breeding technic, for it chows that the method owes its success not to selection in self-fertilized lines, but to the unrecognized differences in genotype of the foundation plants. Jenkins’ results suggest the possibility that an appreciable fraction of the individual plants in open-pollinated varieties may be as high in yield genotype as the best present inbred lines. Obvious- ly, the identification of these plants near the beginning rather than near the end of the breeding operations would make for greater efficiency, for it wouLd concentrate the analysis upon populations with the highest content of desirable genotypes* In the few outstanding selecte- strains it would be feasible to use test-controlled selection in the first selfed generation, where genetic variability is at its maximum, ouch selection might reasonably be expected to accomplish further improve- ment in yield. This is an effective and practicable method for the furtner sampling of the open-pollinated varieties. It is not widely used in corn breeding at present, chiefly for these reasons: (1) The frequency of high yield genotypes among the plants of open-pollinated varieties is low enough to make their identification much less economical than that of comparable genotypes in populations of - various types which may be produced by the use of the highly improved lines now at hand* (2) The exceptional genotypes identified are virtually unselected as regards characters other than yield. Some of these characters are very important in practice, often more important than a considerable increment in yield. The oritical factor determining the practical feasibility of varietal sampling is the frequency in the varieties of genotypes 575 mnnroximating the yield level of the present elite i sn t^ r ad ia nt sa . av Ta hi el a lb il me i (all for trials in single seasons) h xi ng ch i cv aa tr ei a rb ai tl hi et ry in yield genotype among plants of v a or pie et ni e ps ol, l ia nv .-e raging about 9% of the mean yield v aa fr ti ea rn c re e md ou ve a l to o f ex tp hee rimental error. The distribution i on f t yh ie es le d po ep vu el ations is normal. The data unfortunatel w yh e dr oe nt oh e sp .r oe ws ent elite lines would fall upon c tu hr ev se es . disT th re i bg ue tn ie or na l experience of corn breeding in the p i as s tp r 2o 0b a yb el ay r oa better basis for estimating the f i rn e qt uh ee n cf yo u on fd a pt li ao nn t sv arieties which approximate the elit O en yt ih ei ls d b la es vi es l.a fair estimate of this frequency is 1 or g per cent. Despite its relatively low return, the furth t eh re so ap me pn l- ip no gl l oi fn ated varieties is essential. The gr h ey ab tr ei rd pc ao rr tn on fo w . hg er own is the product of various combin a a td io oz ne sn oi fn b ar be od u tl ines. Each of these represents g e an o st iy np ge l, e f gi ax me ed t ea s a homozygous diploid for controlle T dh os ce o, m biw ni at th i ot nh .e additional lines of promise fo c ro n fs ut ri tt nu et re ba r em ei dn iu nt ge , sample of the gamete populati v oa nr si et oi fe s t. h e T fo o uc no dn af ti in oe n further breeding to the reco e mm ba ii nl a tg ir oo nu sp oo ff tg he no ̂types is to reduce its ultim a an t ee x pt oe sn st i bw ih li ic th i ec sa n tn oo t be accurately estimated from a b vu at i lw ah bi lc eh m eu vs it d enb ce e pretty drastic. Moreover, any n f er wo m l it nh ee pr re oc do um cb ei dn ation of the old lines is limited i f no r i tn so pl ri an ce t ig ci av le s go , od combinations with lines to which it is re d Now these varietal populations, in which o f 1 t oh re 2m e pm eb re r cs e nr te ach the elite level, are populations p la ofn ts o. p en-E pac oh l lip nl aa tn et e represents a random combination o t fh e twv oa ri ge at ma el t esg a om ie te population. The yield potentia t lh e o fr e ts hu el t p lo af n td o im si nant factors contributed by T th he e f tr we oq u pe an rc ey n to !f g ge lhen the te a s th ey rb ri isd or mixed population, the YP of the tested individual is th e ex cess of the Fq over a hypothetical yield which would be prod b uy c eb di otypes representing the gamete population of the teste q ru .a nt Ti ht iy s is indeterminate, but since it affects all test cross e q yu ia el ll dy s its determination is unnecessary. In practice, YP wit e hr e rn ec fe - to a hybrid or mixed tester m y be determined as accura a ts e lt yo a homozygous tester, since the number of plants of ea c cr ho s ts e sr te -o uired for an adequate yield test is large enough to r n ee ng dl ei rg ible any variation due to individual plant variability. In the absence of direct evidence, it is necessary to m c ae kr et ain assumptions regarding the inheritance of YP. The vali o df i tt yh ese assumptions for the present purpose does not re t qh ue iy r eb e p &r ecisely correct in specific instances but rath r ee rp r te hs ae tn t t hc eo yr rectly the general or average interaction of the f i an cv to ol rv se d. All assumptions regarding inheritance of YP in thi c su s ds ii so -n are derivable from two postulates which are in harm th oe n ye v wi id te hn ce now available but which still require direct experimental verification. These postulates are as follows: (1) The YP of an individual is the sum. of the YP's of its parental gametes. (2) The mean of the YP's of the gametes produced by an individual is equal to the mean of the YP's of its parental game te s. In the initial stage of an isolated corn breeding progr t ah me , gamete cannot be made the unit of selection, since th h eo rm eo g ie sn e no ou s gamete population with which the varying gamet m ia cy sb ce r ic eo s mbined for comparative testing. It is there!ore^nec t eo s ss ae rl ye ct among the plants produced by the random combin g aa tm ie ot ne s o of all levels. After an initial series of inbreds d s iu sp te ir ni co tr l yt o the varietal means has been established, it is to p ou ss se i th e ese inbreds in further sampling of^the varieties, and i t nh is procedure the gamete may be tne unit oi selection. Gamete selection in practice would ordinarily involve twO( steps: (1) The selection, on the basis of outcross yield tests, of individual plants of a variety/inbred population, and (2) A similar test-controlled selection in the first genera tion self-progeny of the outstanding individuals iden- tified in the first step. This would^ ordinarily be followed by continued selfing, with visual selection, to fix a lino homozygous for the desired agronomic characters as well as yield genotype. 577 For some purposes continued selfing would be unnecessary; notably for the extraction of plants of value in complex crossing. Complex crossing for the extraction of improved lines has been little used in corn breeding, chiefly because of the limited number of good lines available. But homozygosis is not essential in the strains used in complex crossing, and the heterozygous strains identified in the plant selection and gamete selection tests may be used without sacrifice of the established inbreds. The technic may be illustrated by an experiment now in pro- gress* The variety used is Midland, which has given exceptionally good yields among open-pollinated varieties in central and southern Missouri and in other localities in the southern Corn Belt. The inbred used is WF9, which is outstanding in performance among lines now available in the Corn Belt, though it is a little too early to make full use of the growing season in Missouri. It is one of the parents of U, S* 13(WF9/3S-11 x L317/Hy) the hybrid now most widely grown in Missouri. Each Midland/WF9 plant is selfed and is outcrossed on a tester stock, in this case L 317/Hy. Each outcross tests the yield potential of one Midland gamete added to that contributed by the uniform gametes of WF9. Similar outcross tests on L317/Hy are made for comparison from the line WF9, and from Fp's of WF9 with various inbreds of outstanding performance in this region. Any Midland/WF9 plant which excels the performance of WF9 in outcross yield tests under varying and representative conditions represents a Midland gamete superior in yield potential to WF9, in a combination in which WF9 is very effective. The selfed progeny of such a plant provides a population in which further improvement by test-controlled selection should be possible. This selfed progeny is comparable to the F2 of a cross of WF9 with an unrelated elite line. As compared to such F2*s it has, in addition to its possible advantage in yield genotype, the merit of avoiding interbreeding of the tested lines. A derivative of VJF9 x L317 cannot be used effectively with either WF9 or L317; a derivative of WF9 x Midland can be used with any other line except WF9. In comparison with seifs of plants selected from the pure variety, the variety/inbred seifs have certain distinct advantages and disadvantages. For brevity the former will be referred to as the plant-selection series and the latter as the gamete-selection series. The chief advantage of the gamete-selection series is the expected superiority in yield potential of the best individuals in the population, or in the limited sample of the population which may be effectively tested for yield-genotype. It has in addition the following noteworthy advantages: (l) A probably greater range of segregation for yield potential in the selfed progeny of the selected individual. This segregation is 578 the basis for any further improvement in yield which may be made by a second application of test-controlled selection in the selfed pro- geny of the selected plant. The extent of this segregation is de- pendent upon the difference in the specific yield-controlling genes contributed by the parental gametes. The yield potential of the se^ lected plant would benefit as much, on the average, from five such genes, each contributed by both parents, as from ten, each contributed by only one of the parents. But the possibility of further improve- ment in yield potential would come only from the latter. It would be expected that a self of an outstanding Midland plant, representing a combination of one superior Midland gamete with another, would be heterozygous for fewer yield factors than a self of a Midland/WF9 plant of equal yield potential, representing a combination of a superior Midland gamete with a superior^gamete type of unrelated origin. The evidence available is very limited, but in- dicates that this difference is an important one. (2) A better opportunity for extracting a lino satisfactory in characters other than yield. In a series of Midland seifs, the only selection for such characters previous to yield testing would be that made among the individual foundation plants. It may be ex- pected that the plants of highest yield potential might in many cases be unsatisfactory in other respects. The series of Midland/WF9 seifs is also virtually unselectod, but since each plant is heterozygous for the favorable agronomic characters of WF9 it should be possible, in the extraction of homozygous lines from the selfed progeny, to avoid undesirable characters which are not common to the Midland selec- tion and to WF9. This advantage will vary with the line used, but in major characters such as strength of stalk, for example, any elite line selected for use in this type of experiment would provide some insurance against the weaknesses likely to be met within unselected genotype of the open-pollinated varieties. The chief disadvantages of the ^mete-selection series are the following: (X) in gamete selection it is impossible to fix the genotype selected from the variety; it can be used only to extract a combination of this gonotype with some other genotype chosen in advance, (such the W F a9 s genotype in the present example). The line ultimately derived from this combination is restricted to use in cros W sF e9 s. not involving In plant selection a new line is derived which may be combined with other lines without restriction, and which may be crossed for fur- ther improvement with linos chosen after the properties of the selected Midland line are known. 2 (2) In yield testing to compare the value of the Midland gametes, the gametic genotypes compared represent only half of the genotype of the plants which are tested; in plant selection the geno- types compared are the total genotypes of the plants tested, n more accurate yield test is therefore required to detect significant 579 differences in the gamete-selection series- The accuracy of yield tests is limited, and this imposes a minimum limit to the difference in yield potential which may be used in breeding- Furthermore, in- creased accuracy is expensive, and reduction of the standard error to one-half requires yield tests about 4 times as extensive. If differ- ences only half as large are to be detected, only about one fourth as many items could be tested with equivalent outlay. The gamete-selection series would involve smaller differences than the plant-selection series, but the differences to be expected are considerably more than half as large- The net variability of the outcross test yields, after removal of the superimposed variability due to experimental error, is the measure of the yield potential of the plants tested. The yield potentials of a series of open-pollinated Midland plants are the sum of the yield potentials of the male and female gametes combined* These may be represented as follows; YP of Male Gametes A ± an YP of Female Gametes 3 ± YP of 0. P. Plants (A + B) ± / ^ + aB2 In wholly unselected series, A and B are equal and the yield potential of the open-pollinated plants is 2A ± /TT * aA The yield potentials of the plants of WF9 x Midland would be as follows: YP of Male Gametes A ± ak YP of Female Gametes C l 0 YP of Fj_ Plants (A + C) ± aA The number of tests of adequate precision that could be male^ with a given outlay would bo about half as great for the gamete-selection series as for the plant-selection series. In view of the increased frequency of exceptional genotypes in the gamete selection series, the smaller sample* would have a much higher probability of including ex- ceptional Midland genotypes than the Larger. During the past season direct evidence on some of these points was secured in a yield test, conducted in collaboration with D. C* Anderson, at Malta Bend, Mo- The items tested included out- cross tests (on L317/Hy) of the following: (1) 41 Midland plants (2) 37 Midland/WF9 plants (3) the line WF9, (entered for increased precision as 4 items) (4) 6 other elite lines (38-11, R136, 9A0, C.I.7, Kys, and K4) (5) 10 Fq's of elite lines, included to check the additive inheritance of YP* 580 Groups (l) and (2) each included 27 plants representing a wholly unselected sample, with additional plants from visual selection which proved unrelated to yield, These two groups thus represent respectively the zygote and thu gamete population of the Midland stock used. The test was planted as a 10 x 10 triple lattice, with 12 replications. Calculation of the data is not yet completed but the results in general are evident from direct calculation as a randomized block experiment. On this basis the least significant difference is 4-5 bu. per acre. The test-cross yields of the Midland plants varied from 60.3 to 77.8. Those- of the 7 elite lines ranged from 61.8 to 77.0, that of WF9 being 64.1 bu* per acre. The test-cross yields of the F1 ,s and parent inbred lines were in general in good agreement with expecta- tion on the additive basis, though the differences between the lines crossed are not large enough to make this a very significant test of YP inheritance. The test-cross yields of the Midland/WF9 plants in- dicated yield levels for homozygotes of the Midland gamete genotypes ranging from 46.8 to 83.8 bu. per acre. Seed was produced in 1944 for a further trial of plant and gamete selection in the varieties, Kansas Sunflower, Clarage, and Mid- land, with certain modifications of method. It may be desirable in practice to apply gamete selection not to the unselected gamete popu- lation but to a selected population secured from the exceptional plants identified by a preliminary test-controlled plant selection. To test thu feasibility of this modification, the unselected plants in the varieties mentioned are selfed and test-crossed as before and are also crossed on the inbred line selected for use in gamete selection. The gameto selection series from unselected plants may be made up from these crosses, and that from selected plants or mixtures may be made up from them after the plant selection tests have been made. Each vari- ety thus yields three distribution curves, representing the unselected plant population, the unselected gamete population and the selected gamete population. Among the inbred lines included for comparison are K4, a line of excellent performance which was extracted from Kansas Sunflower, K201C, an excellent line extracted from Midland; and 3 Ohio lines which represent the best extractions previously made from Clarage. The position of these lines on the plant and gamete distribution curves of their parent varieties should provide a more definite basis for es- timating the possibilities of plant and gamete selection as compared with the methods used in producing our present inbreds. L. J. Stabler 2. Redox relationships in the development of anthocyanin. Keeble and Armstrong, Wheldale-Onslow, Atkins, and others have presented evidence suggesting the presence of oxidase enzymes and an oxidation system associated with the development of anthocyanin. In repeating the studies made by these early workers it is possible, in the light of re- vised redox methods, to correct several of the interpretations of the 581 use of oxidase indicators, and it now appears that the oxidase enzyme of the earlier workers is in fact a lipid absorptive and oxidative system. It became increasingly apparent during the course of the pre- sent study that there is a localized absorption of the oxidized form of the common redox indicators in unsaturated fats present in anthocyanin bearing cells. The oxidation of p-phenelenediamine, OC -naphthol, leuco methylene blue and related indicators prior to their introduction into sections of r°h and rS tissue will give, in uniform and comparably cut sections, a greater localization of colored indicator in r°k tissue. An iodimetric method applied to this absorptive system, in appropriate- ly prepared tissue, has made possible a qualitative study of differences between colored (rch) and colorless (r&) tissue and has given an exact iodine number for different tissues where weak anthocyanin development, dependent upon R alleles, is to be compared with more strongly colored rch tissue. Iodine absorption is always greater in anthocyanin bearing cells; hence practicable microscopic qualitative observations may be compared with macroscopic anthocyanin distribution, and differences in intensity of pigmentation, by using the iodine number as a qualitative guide. The higher iodine absorption of anthocyanin bearing tissue may be seen to be localized in free plasmal lipids, in lipid material localized in "mitochondrial1’ or lipoclastic bodies in the cell, and in lipids inpregnating cellulose walls. The lipids are highly unsaturated condensation aggregates and not true glycerides. They are not readily soluble in ordinary fat solvents but are soluble in petroleum ether after preliminary hydrolysis of the tissue and extraction with an alkaline/alcoholic mixture. The unsaturated lipids in colorless (r&) tissue have a higher peroxide number as determined by oxidation of ferrous ammonium sulphate. The extracted lipids from rc^ tissue have 40% greater absorptive capacity (Wij*s Iodine Method) than comparable extracts from rg tissue. Presented in the table below are the iodine numbers of leaf tissue of rc^ and rS sib comparisons, as determined by halogen solutions of increasing concentration. The samples were hydro- lized to prevent iodine addition to starch and to facilitate iodine addition to unsaturated bonds; they were dried under nitrogen to con- stant weight and a standard iodine method with thiosulphate titration was used and endpoints were determined galvanometrically in some cases. The samples used ranged in weight from 0.020 mg. to 0.155 mg. so that the method may be applied to small samples of tissue that are held in ethyl alcohol (not above 50%), in order to remove chlorophyll, anthocyan- in, etc., with frequent changes of alcohol to facilitate elution. At all stages in the process storage under nitrogen prevents oxidative degradation and a drop in iodine values. Halogen solutions of increasing concentration I II III IV rch 3*55 9.24 12.55 50.54 rg 2.21 6.91 10.34 44*22 582 Using the methods outlined above a study was made of the development of pigment in excised leaves in culture. It was found that additions of dilute emulsions of unsaturated fats (corn oil, soybean oil, linseed oil) and various terpenes (thujone, etc,) greatly increased the production of pigment, but only when sugar was also pre- sent, Glucose solutions (16 X 10“ 3 molar) were less effective than glucose (8 X 10”3 molar) plus unsaturated fat emulsions (.4%)* Holding the cultures under anaerobic conditions (under nitrogen) for the first two days of a culture study inhibits production of anthocyanin but increases overall pigmentation after aerobic conditions are restored. In the table below are the iodine numbers from a typical sugar culture experiment, A marked decline in iodine number in rg and a final rise in rch with pigmentation is clearly demonstrated. All tissue from same leaf rch r S Fresh Tissue 45-95 (colorless) 51,90 (colorless) Sugar/Anaerobic 41.70 " 44.22 " Sugar/Same as above, 50,54 (Anthocyanin) 40.02 " but exposed to air one day. In vitro preparations of anthocyanin extracts and unsaturated fat emulsions reveal that anthocyanin is a hydrogen acceptor and acts to dehydrogenate and oxidize the fat, and the anthocyanin becomes partially reduced and in some cases irreversibly reduced. This dehy- drogenation of fat emulsions by anthocyanin is stronger when water extracts of rcH tissues are added to the emulsions- Microscopic sec- tions of anthocyanin-bearing tissue held under anaerobic conditions and at a pH of 7-0 to 7.4 show a reduction (loss of color) of anthocy- anin in lipid granules in the plasma under intense illumination and a restoration of color on diminishing the light. This is direct evidence of a reversible redox relationship between lipids and anthocyanin pigments. It is generally true that anthocyanin bearing cells are epidermal, hypodermal or bundle sheath cells which have an excess of lipid material, and it is a general rule that cells low in lipids are lacking in anthocyanin. This fact may be determined by iodine staining in combination with extraction methods outlined above. It is illustrat- ed in corn by the siliceous epidermal cell which, unlike its couplet partner, the fat-bearing suberized cell, lacks anthocyanin unless cul- tured in sugar/fat media under nitrogen followed by oxygen. Fatty and other organic acids, as revealed through the use of polychrome stains and direct acid value determinations are present in anthocyanin bearing cells before pigment is produced and there are apparently less free acids after pigment production. Preliminary trials on B determined pigmentation indicate there is in lipid/pigment development a redox relationship similar to that obtaining in Rr alleles. Trials on the other higher plants 583 (Andropogon, Coleus, Petunia, Acer, etc.) reveal a similar redox prob- lem in floral and autumnal anthocyanin development. In summation, it now appears that the oxidase system, be- lieved by early workers to be causal in anthocyanin development, is in reality a reflection of the oxidized and dehydrogenated state of lipids which absorb and possibly oxidize redox indicators. The absorp- tion of iodine by these dehydrogenated lipids reveals qualitative but not absolute quantitative differences between pigmented and non-pig- men ted tissues. Anthocyanin acts in vitro to bring ..bout the dehydro- genation of fats, and wherever anthocyanin appears in the plant asso- ciated with a lipid system the fats are more dehydrogenated than in comparable non-pigmented tissue. D. S. Van Fleet 3. Comparison of ultraviolet and X-ray deficiencies. Earlier examinations of ultraviolet induced deficiencies in maize indicated that they were terminal, whereas X-ray deficiencies appeared to be usually, perhaps always, internal. Since non-homologous pairing of pachytene chromosomes frequently occurs, this point could be settled only by a study of a chromosome arm irith a terminal cytological marker. In oruer to select plants with breako in this arm, a gene affecting a seedling character was essential. Enoades reported bronze (bz) in the short arm of chromosome 9 (corn letter 194-3) • It was found that in the presence of certain Rr alleles, distinct color developed at the tip of seedling leaves with Bz 'out failed to develop with bz. De- ficiencies of the bronze locus were induced by irradiation of mature pollen from a knob-bed-9 stock, wx-Bz-knob. Pollinations were made on a homozygous or heterozygous bz_ stock, Wx-bz. The colorless-tip Fq plants which subsequently developed bronze pigment instead of an- thocyanin furnished the cytological material. The usual acetocarmine smear technique was employed. In the ultraviolet group, 3513 seedlings Wore examined of which 9 possibly tipless died in early seedling stage and 9 were bronze plants. In the X-ray group, 1670 seedlings wore examined, of which 7 possibly tipless died in the early seedling stage and 11 were bronso plants. The cytological study of the bronze plants is summarized in the table. 584 Kinds of Chromosomal Change 1 break 2 break rearrangement Not No. bz Haploid Terra, def. Int.def. Ring Chro- Def. ana- plants mosome trans. lyzed Ultra- violet 9 2 4 0 0 2 1 X-ray 11 0 0 1 3 5 2 In the ultraviolet material single breaks in the short arm of chromosome 9 gave terminal deficiencies (with the loss of the knob) in h plants* The shortest deficiency, about one-third of the arm, re- moved the bronze locus and gave less than 1% crossing over betv,reen the break and the wx locus* In two cases breaks in different chromosomes were followed by rearrangement in such a way that parts of both chro- mosomes were lost and only one translocation chromosome survived. These have been called deficiency translocations. In pachytene the trans- location chromosome pairs homologously with parts of the two normal chromosomes, and the two single strands usually pair non-homologously to give a three-armed translocation figure. At diakinesis and meta- phase I, this association appears as n chain of three chromosomes or, less frequently, as a pair and a univalent. Anaphase I shows 9-10 separations or occasionally 9-9 with a lagging univalent* Pachytene preparations were not clear enough to determine exact points of break- age in the chromosomes. All X-ray deficiencies resulted from rearrangements involving two breaks within the same cell. In one case both breaks were in the short arm of chromosome 9, giving an internal deficiency. In 3 cases breaks occurred in both arms of 9, a ring fragment which included the centromere being formed. Five deficiency translocations were found. In the case giving the best cytological preparations (involving chro- mosomes 9 and 5) both breaks appeared to be at or very near the spindle fiber regions. There were no cases of terminal deficiency. Many plants with deficiency translocations (in this and other material) show a higher percentage of normal pollen than can be accounted for by random distribution of the three associated chromosomes at the first meiotic division. Katherine 0. De Boor 585 II. 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Jour. Agr. Res. 69:335-372. 1944. Arbuthnot, K. D# Strains of the European corn borer in the United States. U.S.D.A. Tech. Bui. 869. 1944. Barber, G. W. Husk development of sweet corn as affected by moisture supply, an important factor in corn earworm control. Jour. Agr. Res. 63:73-78. 1944* Bear, R. P. Mutations for waxy and sugary endosperm in inbred lines of dent corn. Jour. Amer. Soc. Agron. 36:89-91. 1944. Bernstein, L. Amylases and carbohydrates in developing maize endosperm. Amor, Jour. Bot. 30:517-526. 1943. __________ Hybrid vigor in corn and the mobilization of endosperm re- serves. Amer. Jour. Bot. 30:801-809. 1943. Bigger, J. H. and others. Corn borer numbers increase. 111. Agr. Exp. Sta. Circ. 576. 1944. 586 Borgeson, C. Methods of detasseling and yield of hybrid corn. Jour. Amer. Soc. Agron. 35:919-922. 19A3. Bowers, J. L. The effect of spacing and number of plants per hill on the yield of eleven sweet corn varieties. Amer. Soc. Hort. Sci. Proc. A3:275-277. 19A3. Brooks, J• S. and C. B. Cross. Performance tests of corn varieties and hybrids, 19A3. Okla. Agr. Exp. Sta. Bui. 277. 19AA. Cameron, J. Chromosomes of a maize relative, Polytoca macrophylla. Amer. Jour. Bot. 30:77^-778. 19A3. Coulter, F. C. The ancestry and history of sweet corn, chiefly Golden Bantam. Seed Yforld 55(A): 3-9. 19AA- Crim, R. £. and others. Maturity ratings of corn hybrids registered for sale in Minnesota in 19A3. Minn. Agr. Exp. Sta. Bui. 37A. 19A3. Cutler, H. C. Medicine men and the preservation of a relict gene in maize. Jour. Herod. 35:291-29A. 19AA- Down, l1.. E., J. W. Thayer Jr. and E. Vander Meulen. Sampling ear corn for moisture determination. Jour. Amer. Soc. Agron. 36:A6l-A63. 19AA. Dungan, G. H. Yield and bushel weight of corn grain as influenced by time of planting. Jour. Amer. Soc. Agron. 36:166-170. 19AA. ________ Yields from single-plant hills vs. multiple-plant hills at the same population of corn plants per acre. Jour. Amer. Soc. Agron. 36:996 (abstract). 19AA- ________ and B. Koehler. Age of seed corn in relation to seed infection and yielding capacity. Jour. Amer. Soc. Agron. 36:A36-AA3. 19AA. --------, J. H. Bigger, A. L. Lang, 0. Bolin, and B. Koehler. Illinois hybrid c o m tests 19A3. 111. Agr. Exp. Sta. Bui. 500. 19AA. Earley, E. B. and E. E. De Turk. Time and rate of synthesis of phytin in corn grain during the reproductive period. Jour. Amor. Soc. Agron. 36:803-81A. 19AA. Eckhardt, R. C., L. R. Parish, and E. A. Gurry. Nev. hybrid of sweet corn for the south. Miss. Farm Res. 7:1-3. 19AA. Eldredge, J. C. and P. J. Lyerly. Popcorn in Iowa. Ia. Agr. Exp. Sta. Bill. P5A. 19A3. 587 Enzie, W. D. Descriptive and historical study of some yellow sweet corn hybrids. N.Y. State Agr. Exp. Sta. Bui. 705. 1943. Flint, L. H. Light and the elongation of the mesocotyl in corn. PI. Phys. 19:537-543. 1944. Genter, C. F. A study of the inheritance of susceptibility to leaf blight of corn. Ohio State University, Abs. Doctoral Diss., No. 40 pp. 97-107. 1942. Grafius, J. F. and L. R. Hehn. South Dakota, corn performance test, 1943. So. Dak. Agr. Exp. Sta. Circ. 50. 1944. Hayes, H. K., E. H. Rinke, and Y. S. Tsiang. The development of a synthetic variety of corn from inbred lines. Jour. Amer. Soc. Agron. 36:998-1000 (abstract). 1944* Hehn, E. R. and J . E. Grafius. 1942 South Dakota hybrid corn yield test. So. Dak. Agr. Exp. Sta. Circ. 45. 1943. Hendricks, W. A. and J. C. Scholl. Techniques in measuring joint relationships; joint effects of temperature and precipita- tion on corn yields. No. Car. Agr. Exp. Sta. Tech. Bui. 74. 1943. Ho. U* Soil inhabiting fungi attacking the roots of maize. Ia. Agr. Exp. Sta. Res. Bui. 332. 1944. Jones, D. F. Ecuilibrium in genic materials. Proc. Nat. /lead. Sci. 30:82-37. 1944- _________ Growth changes in maize endosperm associated with the re- location of chromosome parts. Genetics 29:420-427. 1944, _________ Better corn crops in 1944- Rural New Yorker 103:274. 1944. _________ Sweet corn for home gardens. Horticulture 22:152. 1944- Jugenhoimer, R. W., A. L. Clapp, C. D. Davis, and C. R. Porter, Kansas Corn tests, 1943- Kan. Agr. Exp. Sta. Bui. 323., 3944. Kemp, W. B. and R. G. Rothgeb. Selection and genetic responses in a segregating maize population. Md , Agr. Exp„ Sea, Eui. A26. 1943- Kiesselbach, T. A. Character, field performance and commercial production of waxy corn. Jour. Amer. Soc. Agron. 36:668-632. 1944- Lonnauist, J. H. a,nd R. W. Jugenheimer. Factors affecting the success of pollination in corn. Jour. Amer. Soc. Agron. 35:923-933. 1943. 588 McClintock, B. The relation of homozygous deficiencies to muta- tions and allele series in maize. Genetics 29:173-502. 1944 • Miles, S. R. Choosing corn hybrids for Indiana* Ind. Agr, Exp. Sta. Bui. 192. 1913* Moore, R. P., J. A. Rigney, G. K. Middleton, and L. S. Bennett. Official variety tests - 1913* No. Car. Agr. Exp* Sta. Bui. 313. 1914. Paddick, M. E. Vegetative development of inbred and hybrid maize. Ia. Agr* Exp. Sta. Res. Bui. 331* 1911* Phinney, B. 0* Gene action in the development of the leaf in Zca mays. Airier. Jour. Bot. 31:4 (abstract). 1941* Powers, LeRoy. An expansion of Jones's theory for the explanation of heterosis. Amer, Nat. 78:275-230. 1911* Randolph, L. F., E. C. Abbe, and J. Einset. Comparison of shoot apex and leaf development and structure in diploid and tetraploid maize. Jour. Agr. Res. 69:17-76. 1944* Reeves, R. G. Chromosome knobs in relation to the origin of maize. Genetics 29:111-147. 1941. Rhoades, M* M* and A. Carvalho. The function and structure of the parenchyma sheath plastids of tire maize leaf. Bui. forrey Bot. Club 71:335-346* 1944. Richey, F. D. Maize hybrids susceptible to ear worm. Jour. He.red. 35:327-328. 1944. _________ The shattered dream of a corn breeder. Jour. Amer. Soc. Agron. 36:267-268. 1944* Rife, D. C. Mutation in corn pericarp. Ohio Jour. Sci. 44:143- 144. 1944* Robertson, D. W #, A. M. Lute, .and H. Krocger. Germination of 20-year- old wheat, oats, barley, coin, rye, sorghum, a. a r,j./'uenr s.. Jour. Amer* Soc. Agron. 35:73o~795» 1Q/!• Robinson, J. L. and F. Reiss* The 1943 Iowa corn yield test la. Agr. Exp. Sta. Bui. P58. 1944- Scott, G. C. and R* 0. Bclkengren. Importance of breeding peas and corn for quality. Food Res. 9:371-376* 1911. 589 Semeniuk, G. Seedling infection of dent maize by Sclerotium bataticola. Phytopath* 34:838-843. 1944. Shank, D. B. Top—root ratios of inbred and hybrid maize. Jour. Amer. Soc. Agron. 35:976-987. 1943. Shollenberger, J. H. and C. M. Jaeger. Corn, its products and uses* U.S.D.A., Bur. Agr. and Indus. Chem., 1943, ACE-121, rev., PP. 47. Singleton, W. R. Noyes Darling, first maize breeder. Jour. Hered. 35:265-267. 1944. Stadler, L. J* The effect of x-rays upon dominant mutation in maize. Proc. Nat. Acad. Sci* 30:123-128. 1944. __________ Gamete selection in corn breeding. Jour. Amer. Soc. Agron. 36:988-989 (abstract). 1944. Stakman, E. C.^M. F. Kernkamp, W. J. Martin, and T. H. King. The inheritance of a white mutant character in Ustilago zeae. Phytopath. 33:943-949. 1943. Stakman, E. C., M. F. Kernkamp, T. H. King, and W. J. Martin. Genetic factors for mutability and mutant characters in Ustilago zeae. Amer. Jour. Bot. 30:37-48. 1943. Standen, J. H. Chemical and physical characteristics of maize cobs in relation to the growth of Nigrospora oryzae. Phytopath* 34:315-323. 1944. Sweet, R. D. and C. B. Raymond. Sweet corn for marketing and pro- cessing. Cornell Univ. Agr. Exp. Sta. Ext. Bui. 644. 1944. Ullstrup, A. J. Diseases of dent corn in the United States. U.S.D.A- Circ. 674. 1943- ___________ Further studeis on a species of Helmithosporium parasitizing corn. Phytopath. 34:214-222. 1944- Wellhausen, E. J. Results of hybrid corn trials in West Virginia for 194?. W. Va. Sta. Mimeo. Circ. 46. 1943 Whaley, W. G. and A. L. Long. The behavior of excised roots of heterotic hybrids and their inbred parents in culture. Bui. Torrey Bot. Club. 71:267-275. 1944. Whiting, A. F. Origin of corn: an evaluation of fact and theory. Amer. Anthrop. 46:500-515. 1944. Wiidakas, W. Hybrid seed corn production. N. Dak. Agr. Exp. Sta. Bimo. Bui. 6:3-4- 1944. R. L. Cushing Cornell University 590 III. SEED STOCKS PROPAGATED IN 1944 Slightly more than 200 cultures were grown last summer. About half of these were the hybrids between weak stocks and non-related inbreds made by Dr* Murray in 194-3► A few plants were selfed in each of these cultures. This program was carried along by growing still other weak stocks and crossing them with inbreds. It is hoped that in the course of a few years most of the useful genes can be put into vigorous combinations of this kind. In coopera- tion with Dr. Randolph, a beginning was made of the transfer of a good marker gene or two to each of the trisomic stocks now available. Combine.tions involving trisomic V, VI, IX, and X were obtained this year. R. L. Cushing and Rosalind Morris 591 MAIZE GENETICS COOPERATION NEWS LETTER 20 April 15, 194-6 The data presented here are not to be used in publications without the consent of the authors. Department of Plant Breeding Cornell University Ithaca, N. Y. 592 Announcement 2 I, Reports from Cooperators ...................... . 3 Connecticut Agricultural Experiment Station . . 3 Cornell University ............................ 4 Florida Agricultural Experiment Station . . . . 9 Harvard University ............................. 14 University of Minnesota ...................... 15 Missouri Eotanical Garden and Pioneer Hi-Bred Corn Company . . . . . . . . . . 19 Nev/ fork State Agricultural Experiment Station . 21 Pioneer Hi-Bred Corn Company .................. 22 University of S. Paulo...................... .. 23 U. S. Department of Agriculture and Cornell University 25 II Maize Publications .................... 27 Ill Seed Stocks Propagated • • ........ . . . . . . . 33 Report of California Institute of Technology • • . 34 CORNELL UNIVERSITY COLLEGE i URE DEPARTMENT OF PUNT-bREtUif" I T H A C A , ISJ Y 593 CORNELL UNIVERSITY COLLEGE OF /IbHIiiULTl/RF DEPARTMENT of PLUT-bS . ■ 1 H a c a , rvj y ANNOUNCEMENT Arrangements have been made to continue the Maize Genetics Cooperation at Cornell University for a period of not less than three years* Professor R* L. Cushing, who has been responsible for the work done during the past few years, will help initiate Professor H. H* Smith who will have charge of the work in the immediate future* The undersigned will enjoy looking on from the outside and offering gratuitous advice as usual. R. A# Emerson 594 I. REPORTS FROM COOPERATORS w :of Connecticut Agricultural Experiment Station 1 o. New Haven, Connecticut 1* In the second generation from crosses of deviating lines with the original normal line, mono-factorial segregation is indicated by dwarf plant, pale top and crooked stalk, (Backcrossed ratio 52 tall; 32 dwarf where 42:42 were expected, F2 selfed 49 green straight, 9 green crooked, 23 pale straight, 3 pale crooked where 47:15:1$: 5 were expected.) Narrow leaf cannot be separated clearly from normal in individual plants, progenies ranged in average leaf width from 74 to 93 mm compared to 72 for narrow and 92 for normal under similar conditions. Average height ranged from 92 to 103 inches compared with 91 for narrow and 95 for normal. In previous tests narrow leaf plants have been slightly taller than normal. Both the extracted homozygous normals and deviates have come out of the cross slightly enlarged, an indication that other factors are involved. Further testing is necessary to establish the significance of these differences. Blotched leaf ana late-flowering types have not yet been compared after extraction from the cross with normal. In view of the fact that the long inbred Learning lines continued to decline in yield during 20 generations it is quite pos- sible that these lines which have not been selfed continuously for this length of time are still segregating for minor physiological changes along with the visible morphological changes which seem to be mutations. The normal lines, in the two cases tested, show no increases when crossed ?/ith the same normal lines from which they have been separate for many generations. Therefore, the possibility of accumu- lation of dominant genes from both parents seems to be ruled out. Further testing of this point is needed. Th^re is the possibility of mutations or delayed segregations affecting combining ability that have no visible effect in the homo- zygous condition or in crosses with the same line from other sources. Three of the long inbred Learning lines selfed for eight and nine generations were separated into two sub lines each and maintained separately for seven additional generations of self-fertilization. During this period they showed no visible differences but when inter- crossed they all gave significant increases in some measurable character. Two of these lines were again separated in the 17th and 22nd generations and further self-fertilized for eleven and six generations. When the first generation crosses between these sub lines wore compared with their normal parents no significant dif- ferences were obtained. In one of these cases the parental lines 595 differed slightly in visible characters. All of this evidence in- dicates delayed segregation from an enforced heterozygous complex. Five of the six deviating lines which show heterosis when crossed back to the normal line have been tested in outcrosses with unrelated lines. No significant differences in yield of grain wore obtained between crosses of normal by unrelated normal compared to deviating line by the same unrelated normal. For practical purposes it is important that there were no decreases in yield. D. F. Jones 2. A method for making smears of root tip chromosomes. Frequently it is necessary to have counts of root tip chromosomes, but the paraffin method for making preparations is laborious and time consuming. However, excellent figures can be obtained quickly and easily by the following technique. Fix young root tips in Carney’s fluid for 6-24. hours. Change to 10% alcohol. (The material can be kept here until it is convenient to make the smears). Transfer to equal parts of hydrochloric acid and 95$ alcohol for five minutes, then to 10% alcohol for at least five minutes. Put a thin cross-scction slice of the root tip into a drop of aceto-carmine on a slide, and tease the material apart with needles, or flatten it with a scalpel. Put on a clean cover glass and press gently with the eraser end of a pencil. Heat slide several times by passing through a flame. Examine to sec whether there are sufficient division figures. If not, make a smear from a different section of the root, or from a different root. A good preparation has the cells well separated but intact, with many well-stained division figures. Temporary mounts can be sealed with a gum-mastic-paraffin mixture and kept in a cool place for several weeks. Or the slides may be made permanent by McClintock's method for making sporocytc smears permanent. Jeannette Lowe Cornell University, Department of Plant Breeding Ithaca, New York Gey and pericarp-color ratios. In two earlier News Letters (17: 8-10, 1943 and 18: 7-8, 1944), aberrant pericarp-color ratios were reported and a gamete factor, Gaz, was postulated as interfering with the functioning of pollen carrying it. There are now available more data like those previously reported and also a few of more nearly crucial importance. The records here assembled include both the new and most of the previously reported data. 596 The study involves crosses of lines having red pericarp and cob with lines having colorless pericarp and either white or red cob color. In this account,cob color will be disregarded, except In ope section where its designation is essential. In general red and colorless (white) pericarp will be designated, respectively, by R and W. When reference to both pericarp and cob colors is made, the following symbols will be used for the three alleles: R-R = red pericarp, red cob W-R = white pericarp, red cob W-W = white pericarp, white cob Certain plants with heterozygous red pericarp, when Qelfed or used as pollen parents in crosses with white, give progenies with an excess of white-eared individuals, instead of the respective 3-1 and 1-1 ratios ordinarily observed. When, however, the same red eared plants are used as pistillate parents in crosses with white, normal ratios result. The ratios of red to white that have been ob- served to date in all aberrant cultures of whatever generations are given in the tabula^ statement below, together with first and later generations of crosses in which heterozygous reds were used as pistil- late parents. Parent plants Number plants0 n 1 Gj|atio % Type Number Red White R W Red W/R (x) 4-9 1231 1085 1.15:1 53.6 W/(W/R) 25 491 1822 . 1:3.71 21.2 (W/R)/W 18 437 453 1:1.04 49.1 Not all red eared plants of cultures with an excess of whites, give aberrant ratios in the next generation. Of 42 plants tested from cultures resulting from W/(W/R), line 2 of the above table, 29 gave aberrant pj'id 13 normal ratios in the following generations. Reds of aberrant cultures, which give normal ratios in later genera- tions, are assumed to have lost Ga 4 by crossing over. But the rela- tive numbers of aberrant and normal progenies resulting is not a measure of the percent of crossing over, because crossover pollen lacking Ga 4- is more likely to function in fertilization than pollen carrying Ga 4. Of red eared F£ plants lacking Ga Ut two out of three in general are expected to be homozygous. Of 61 such red eared plants of aberrant cultures, only 5 ware homozygous, a ratio of 1 1.2:1 instead of the normal 2-1 ratio. Here again, this ratio is not a measure of percent of crossing over between red and Ga 4 alone or of percent of functioning Ga 4 pollen alone, for both variables are involved together. Of red eared plants of normal cultures resulting from (W/R)/W, line 3 of the table above (like those of the reciprocal cross W/(w/R), line 2), some have normal and some aberrant progenies in the next 597 generation. Of 28 such reds tested, 23 gave aberrant and 5 normal ratios in the following generation. Since there is here no question of pollen differentials, the percent of normal cultures should measure the percent of crossing over in megasporogenesis. The percent of crossing over indicated is 17*9, but the number of plants tested is far too small to give reliable results. Of the homozygous red eared plants occurring in aberrant cultures, one was crossed reciprocally with white and two others wore used only as pollen parents in crosses with white. The progenies were all red eared, but, of course, segregated in the next generation. The ratios of red to white in the segregating generation indicated that the throe homozygous red parents were heterozygous for Ga 4* The available data are summarized in the following table. Progenies Type of cross Number Red White 292 901 w/ jIw/W)/(R/H)] a 1 8 260 263 |(W/W)/(R/R)] 40 31W { J 729 263 |(B/R)/(W/W)] 98 69 «*> { ! 112 38 Of 30 segregating cultures from crosses involving homo- zygous red as pollen parents, 9 exhibited aberrant and 21 normal ratios. Of 11 segregating cultures from the one cross in which homo- zygous red was used as pistillate parent, $ gave aberrant e.nd 6 normal ratios. The second of these two catagories (homozygous red as pistil- late parent) should include equal numbers of aberrantly and normally segregating cultures, since, in homozygous red, crossing over with Ga 4 is not detectable and because Ga 4 was not present in the white pollen parent. The $-6 ratio is as near equality as is possible with a total of eleven. The first of the two catagories (homozygous red as pollen parent) should, however, afford a direct measure of the percent of functioning Ga 4 pollen* Here crossing over in microspcrogenesis cannot be detected and should have no effect on the ratio of aberrant to normal segregating cultures in the succeeding generation. Of the 30 plants tested, 9 gave aberrant and 21 normal segregation ratios* This 9-21 ratio indicates that 30 percent of the functioning pollen carried Ga 4, where 50 percent would be expected if this gene did not work to the disadvantage of the pollen carrying it* 598 When,in heterozygous red, the Ga 4 gene is lost from red- carrying gametes, it should be picked up in an equal number of in- stances by gametes carrying white4 For this study, a third allele, colorless pericarp with red cob, W-R, may be used# When plants heterozygous for R-R and W-W are crossed with W-R. the red eared plants are W-R/R-R or R-R/W-R and the colorless eared plants are W-R/W-W or V\r_w/W-R« Data involving the first of these catagories have been presented without reference to cob color. In the second category, pericarp is colorless throughout, but it is perhaps less confusing to designate both pericarp and cob color by symbols for the three alleles involved. When, by crossing over, Ga 4 is shifted from association with R-R to the W-W allele, segregating progenies should show a deficiency of white. In the studies of crosses of R-R with W-W, out-crosses with W-R, as either pollen or pistillate parent, have afforded tests of 137 W-R plants. Their progenies, classified as having normal or aberrant segregation.ratios of red to white cob, are summarized as follows. Progenies Ratio % Number W-R W—W W-R:W-W W-W W-W/W-R (ill 2830 1016 2.33:1 26.1and (x) \ 20 705 - / - U 16.02:1 5.9 w r w w In these col>-color studies, as in the pericarp-color work reported eariier in this account, when heterozygous red (R-R/W-W or W_y«/R-R) is used as the pollen parent in crosses with W-R, there are involved both variables, namely, percent of functioning Ga 4 pollan and percent of crossing over. It is, therefore, impossible to evalu- ate either one of them. When, however, heterozygous red with hetero- zygous Ga 4 is used as the pistillate parent and homozygous W-R as the pollen parent, differential fertilization because of Ga 4 is eliminated, and the percent of crossing over in megasporogenusis should be indicated by the relative numbers of normally and aberrantly segregating cultures in the succeeding generation* Data are available for 32 such cultures, as follows. ]Progenies of W-W/W-R Ratio cffO Type Red White Red White White f W-W + . — /yj-p )'(>•) /28 693 232 2.99:1 25.1 { R-R Ge 4 ' 22.8.:1 4*2u 114 5 599 • 1 0 Hero the ratio of normal to aberrant progenies is 28:4, or 7:1 . The percent of aberrant progenies — equivalent to percent of crossing over — is 12.5* It will be recalled that the study of seg- regating red pericarp, reported earlier in this account,involving 23 aberrant to 5 normal progenies, indicated a percent of crossing over of 17.9* The percent calculated from both the pericarp-color and the cob-color lots, 60 progenies in all, is 15*0* It will be recalled also that crosses of white with homozygous red pericarp, the latter as pollen parent, resulted in 21 normal and 9 aberrant cultures* This indicates that 30 percent of the functioning pollen carried Gay, and 70 percent carried its normal allele. It remains now to see how nearly aberrant ratios correspond to ratios calculated from the indicated values of the two variables. The answer is easy. They do not fit at all welll It is realized that the number of progenies on which the evaluation of the two variables has been based is wholly inadequate — 60 for percent of crossing over and 30 for percent of functioning Gay, pollen. One further method of evaluating the two variables is avail- able. Thi3 method was used by Mangelsdorf and Jones (Genetics 11:423-455, 1926) in their study of the gamete factor in the fourth chromosome. By the use of data involving two genes both linked with Ga. they were able to evaluate the two variables simultaneously. This method can be used with data presented previously. (News Letter 17: 8-10, 1943), These are backcross data involving pericarp color and ms 17, with a total of 206 plants. The method of Mangelsdorf and Jones applied to these data indicates approximately 13 percent crossing over between Ga/t and pericarp color — not far from that calculated by the method of eliminating one variable — but only 5 — instead of 30 — percent of the effective pollen carrying Ga/t. These percentages, when applied to the data sum- marized in this account, show a much better fit to observed ratios than do those obtained from evaluation of the two variables independent- ly as presented earlier in this account. A comparison of the two methods is giv^n in the following table. Ratios Calculated 13 % cross- 15 Observed ing over 5 % Ga 4 30 pollen Coupling — B-C — Red to white 1 - 3.7 1 - 5.1 1 - 1,8 f2 — Red to white 1.2 - 1 1.4 - 1 2.1 - 1 f2 — Heter0- to homo- zygous red 11.2 - 1 6.2 - 1 2.8 - 1 Repulsion *2 — Red to white 16.0 - 1 11.3 - 1 3.6 - 1 600 The data presented in the 19^3 News Letter indicate that Ga/t is to the left of msi 7. On the assumption of 13 percent crossing over between P and Gay,. the map may be given tentatively as below. sr £---- Ga^ £------ 1 0 ------- > msi 7 ----- 3 ------> P -----br A further study, involving Gay, with sr, msi7 . P, and zb/^ is underway, but little further evidence can be obtained short of two more years. R. A. Emerson Florida Agricultural Experiment Station Gainesville, Florida Regression Analyses of Yields of Hybrid Corn and Inbred Parent Lines.— 1. Derivation of a theoretical regression function. For n loci let the basic effect of a gene substitution be d, dominance effect kd, proportions of loci AA in ?\ and P2 be u and w, the multi- ple recessive phenotype T, and gene action additive. P^ = 2und + T, Pp = 2wd + T, F]_ = 2uwnd + [u(l-wT + w(l-u)l (nd + nkd) + T, ?l = (1 + k + kT/nd) {?i +• P2)Z.2-(k/2nd)PiP2-(k/2nd)T2-kT, Fi = b^ P - + 1̂* wbiere P = (P]_+ P2)/2 With each generation of selfing l/2 of dominance effects disappear. Divide each term in k by 2 for each time selfed to obtain the general function for Fn. This function is a surface which is curved if there is any dominance (k not zero). (Regression of F]_ on mean of parents neglects the second term of the function. A plane is fitted where a curved surface provides a closer fit if there is dominance). Regression of Fi on P2 with constant P]_ (any single Fi column in Stringficld's table below) is obtained by treating P]_ as a constant in the main function. ?X = [1/2 + ky2 - k(Pi - T)y2n| P2 + C2 The partial regression coefficient bp is contained in the brackets. Its value manifestly depends upon the value of constant P^. P2 is the independent variable. Substitution of AA for aa at one locus in P2 provides an increment 2d. The corresponding increment of F]_ is [1/2 + k/2 - k(P]_ - T)/2nd] 2d* The first term of this expression, (l/2)2d = d, accounts for the basic effect of an additional A allele in F^ coming from P2. The second term, (k/2)2d = kd, provides a dominance effect. If, however, Pi is AA at that locus no dominance effect will be added to F]_ by the substitution, and the one already there will disappear. P^ is AA at u loci, and (P]_ - T)/2nd = u. The third term adds £-k(P^ - T)/2nd] 2d = -2ukd. 601 Under the assumptions, our main function calculates exactly mean Fp for any type pair of parent values. Variance from such means, or deviations from the regression surface are due solely to variations in degree of heterozygosity. This portion__of the variance is beyond parent criteria. Pros-ait parent criteria P and P]P2 together provide maximum estimation of by parent criteria. It is clear that the mean degree of heterozygosity is greater in crosses of good x poor linos than in crosses oi medium x medium lines and that the products of parents P]P2 is included to measure that variation. It must also be clear that the various genetic Interpretations inserted along have not been employee, in trie mathematical derivations. For the most part they were not recognized until after completion of the algebraic formu- lations. Finally regression of bp on Pi is given by the formula for bp. The regression coefficient is (-k/2nd) which is b2 of the main function. It will bu labeled b2 hero also since the two coefficients are identical. 2. Fitting the functions to data. An unpublished table kindly furnished by Mr. G. H. Stringfield is included to illustrate the process of fitting. Values of bp at the bottom are simply regres- sions of Fi of the respective columns on P2* Regression of the values of bp at the bottom of the table on the values of Pi at the top is -0.015, and the correlation is -0.98 which is highly significant. Fp and parents, bushels p1—er a—c' re', y (\G. H. Stringfield, unpublished) Pi :: 4-8 : 90 Hy 02 : WF9 : 51 : P2 :: 13.6 : 28.2 29.8 46.1 : 51.4 : 55.3 : 4-8, 13*6 76.7 96.3 91.0 : 100.7 : 106.1 : 90, 28.2 :: 76.7 : 81.4 94.2 : 97.9 : 86.4 : t m . Hy, 29.8 :: 96.3 : 81.4 108.9 : 109.8 : 94.7 ! 02, 46.1 :: 91.0 : 94»^ 108.9 104.0 : 100.8 : . ,----- . ♦ « WF9 51.4 :: 100.7 : 97.9 109.8 104.0 : 103.4 : •- • i 51, 55.3 :: 106.1 : 86.4 94.7 100.8 : 103.4 : . w : bp ::.6947 : •L 060 .3433 .2314 : .0516 : .0512 : Mean P2 :: 42.0 : 39.2 38.8 35-6 : 34.6 : 33.8 i Mean F̂ . :: 94.2 : 87.2 98.2 99.8 : 103.2 : 98.2 : 602 From this regression the estimated value of Pp for bp = 0 is 57.1 bushels per acre which is just beyond the range of the date. The same process has been applied to the other sets of data listed in the second table. Where significant values of have been obtained the main multiple regression function has also been fitted. In each case the second estimate of b2 agreed closely with the first one, which provides a computation check since the two are algebraically identical also in the computation formulas* The last five items in the table were then computed by quadratic solution of the multiple regression function on the assump- tion that where P]_ and P2 are both completely aa or completely AA, p]_ = P2 = F]_ - F2* Roots thus obtained are estimates of the bottom recessive and top dominant. 3. Interpretation. First I must note that I have never had any notion that yield of corn could depend upon a multiple set of genes with uniform d and kd from locus to locus. Variation of d and of kd must contribute to the variance of Fi and thus provide additional variance from the present regression surface. Beyond that I doubt that variation of d and kd could confuse present analyses. Evidence here for overdominance (no dominance, k = 0; complete dominance k = ± 1; overdominance k numerically greater than one) seems to lie in the estimated values of Pp for aero partial regression. If dominance is complete, zero partial regression will obtain only when Pp is the top dominant. This statement agrees with long held genetic philosophy of prepotencc. That It is mathematically true in present theory may be seen by setting bp = U and k = 1 in the partial regression coefficient formula and solving to find (P]_ - T)/ 5 rid = u = 1. Note also that with complete dominance the top dominant and top heterozygote are equal. Since for present data, values of completely prepotent P^, (bp =0), are far below mean *1, the only direct interpretation is overdominance, see values of x estimated irom the date.• It would seem to make no difference whether the genes of and ? 2 are completely linked or completely independent, so far as immediate contributions to Fq are concerned. Fisher, (Genetical Theory of Natural Selection) gives the condition for equilibrium where the hetcrozygote has selective advan- tage over both homozygotes for one pair. His mathematical condition is identical with the present one for bp = 0 for any value of k (Selec- tive advantage) except that his condition is in terms of the proportions of a and A alleles in the population at equilibrium. The present con- dition is in terms of u, the proportion of loci AA in P^. If many loci are all at Fisher equilibrium in a cross breeding variety the expected value of u for a homozygote derived without bias is identical with q for the variety. Or if TI for a group of lines is identical with q for equilibrium the lines as a set are at equilibrium. Every line, good or poor, will then have the same general combining ability as measured by the average of its crosses with all of the other lines. Equilibrium for each locus is at the instant where a and A alleles combine equally well with the field. 603 vO 60 P 3« O CM 1 i P P #—1 06 o X 03 H p P ; a , p ct S O cj > •Hp So «lu to •H1 >» -p 06 P O' C3 CO £

O 3 ' o o

» X £ to p -4 U6 (M ■£> •H p rH O B rH »H P 06 P1 Cjh JO O a 5b -6C0 •H P CO 32 a P in t> CM » >Je CX « P O O P 60 CO vO I tH 'd .1 60 tO n- CM & I w o to CM fj\ ir\ T) 60 O St M I 3 I i H d to O ' O ' 60 m in st CM » • t p fr, ■o ay o o CMo 2) t> in e'- •4 cr- 2 p en 06 CM a o 'd p rH l> CM P O•M A• (Vl (6O • • * • • £ P t> NO -4 1 o '4 O O 60 •H O II m r - U6 p to f6C6tO P «m CM H H t 60 CO W Oh CM 60 O CM 8 60 CM r- 06 CM f> CM H tocvno CM Ct- CM O O• Ot O• P• O» WON ON C- P ,Q I I I ! CMT' H CCJM O n •» I * ? ? ? ? ? ? ? ? ? p •* P rH I * -p *> * Hri m r*» £X ^ to c3 03 cj O 0) ‘C'OOO-'T'C'- 3 1 0 2 2 p p o >t (M nO (M a p fe> 06 06 ‘421 a? CM 06 vO vO• 06 P 6 O = 03 CM JO •i d CQ to IX, CM P P CM P * u 03 0> G> — c bx 3a = s T3 & «a P >6 >» *s P co 03 •s p o o & P> P ,-3 o p P3 • 03 t>> P 0) 0 •H °8 <13 1 m * P P 03 P p p CO P to P P P P p • t * • • W) p p O P -P Cj Cl rP 0) H CM C 6 s f tA P CD CO P |5 03 P £ r*l P M UO (0 P 2 u p P P p o p 03 CO u i p a P 604 REGRESSION ANALYSES O F YIELDS O F HYBiID CORN AND INBRED P A R E N T L IN E S Jenkins (1929) almost attained that condition (last 3 entries in present table). For those data the partial regressions are nearly as frequently negative as positive and almost uniformly small numerical- ly. After much selection Stringfield, and Kinrnan and Sprague studied groups of lines which show recession from the equilibrium which well selected varieties had closely approached 20 years or more ago. Reces- sion may be due to mixing lines from different sources in one group and probably to selection for specific combining ability (more than average heterozygosity)• The ceiling for hybrids is higher if one line has fewer AA loci, but this point can hardly be fully demonstrated without a 3-dimensional figure. From the 3-dimensional figure for overdominance of the degree indicated (k = 2) it is clear that the trend for increasing and Po rises steeply over most of the range of present corn breeding experience which just laps over the crest. Beyond the trend is down- wards. Beyond we have hardly gone, partly because of linkage as visioned by Jones and partly because present practice requires slight recession from the crest to another equilibrium between selection for specific combining ability and selection for general combining ability and excellence- of lines themselves. Present interpretations must remain in some degree tentative until lines 'well beyond the crest to provide significant negative partial regressions have been obtained. Before such evidence any alternative interpretation of complex, non-additive gone action would stand entirely refuted, I think. Excess of any heterozygot^ ever the top dominant would seem to be overdominance by definition. The pos- sibility of explaining present results by non-additive action without overdominance is very small insofar as I can tell but spice does not permit more to be said here. Neither does sp ce permit listing of every point where overdominance theory agrees with corn breeding ex- perience more closely than does dominance theory. I h've found no discrepancies and so must siy that the evidence for overdominance must seem overwhelming but not crucial to any unprejudiced mind. It will be appreciated if any discrepancies are pointed out. The suae analysis has been employed with data on other char- acters of Jenkins (loc. cit.) with no evidence of overdominance and in most cases slight evidence of any dominance at ' 11. Height of plant is an exception, but it depends largely on vigor. No data on ear dimensions have been available. Fred H. Hull 605 M . Harvard University, Cambridge, Massachusetts 1. Pod Corn* We now have fertile, true-breeding inbred lines of pod corn. These were obtained by selecting for minus modifiers of the tunicate condition. In these stocks the glumes show about the same de- velopment in the homozygous condition as is usually found in other stocks in the heterozygous condition. Seed of these inbred tunicate lines is now available in considerable quantity# Varieties and inbred strains of maize differ greatly in their modifier complexes with respect to the tunicate character. When varieties and inbreds are crossed to the same stock of tunicate there is in the *i, considerable variation in the development of the glumes. Paraguayan and Bolivian varieties have strong minus modifier complexes. Guatemalan varieties have plus modifiers or at least are lacking in minus modifiers. North American inbred strains cover the entire range. Iowa 701 has a strong plus modifier complex while Minn* A15& is so strongly minus that in some crosses with pod corn the tunicate ears are scarcely distinguish- able from non-tunicate, 2. Modifiers of Secondary Pistillate Florets. The occurrence of varieties of maize in Bolivia in which there is a partial or complete development of the secondary pistillate floret , as in Country Gentle- man sweet corn, suggests that this may be a primitive character. If this is the case, then there may well be differences in maize varieties in their modifier complexes with respect to this character. Preliminary studies made by crossing with an inbred strain of Country Gentleman indicate that Guatemalan varieties have strongly minus modifier complexes with respect to the development of secondary pistillate florets while Bolivian varieties have plus modifiers or are neutral. The results so far as they go, can be interpreted in terms of Tripsacum contamination in Guatemalan varieties and its absence in Bolivian varieties. 3. Nature of the Maize Ear. The hybrids of pod corn and Guarany maize, previously reported, which have been useful in demonstrat- ing the nature of the ear of maize, have produced an additional useful abnormality. In l^*' several plants were found in which one or more ears were norma] *rhilo other ears on the same stalks producea greatly elongated shanks. When this occurs the ear is more or less naked ^nd the shucks which usually surround the ear become normal leaves spaced at intervals on an elongated lateral stem. There is no doubt that the ear was or- iginally the terminal inflorescence of a lateral branch. U* Derivatives of maize-teosinte crosses. The segments of chromatin or blocks of genes which distinguish various types of teosinte from maize have been transferred individually by repeated backcrossing to a uniform inbred strain of maize. Stocks derived by this procedure show that the segment which occurs on chromosome No. 4 in Florida teo- sinte has almost identical counterparts in Durango, Nobogame and "New" teosintes. Whether these counterparts occur on chromosome U in each of these teosintes remains to be determined* These stocks are also useful for testing the effect of teosinte germplasm upon the yield of maize. Preliminary tests indicate that a small amount of teosinte germplasm may improve grain yield. When two or more segments are present, however, even in the heterozygous condition, grain yields are definitely depressed although forage yields may be somewhat improved* P. C. Mangelsdorf 606 University of Minnesota, University Farm, St# Paul, Minnesota 1. Sterility Studies:— Tj-5-6-7. Mr* Constancio Lazaro has continued his study of this stock in Uruguay. He has identified the chromosomes involved in a series of eemistcrile plants derived from the cross: (.)8 x Normal. Of these, 16 are Tp-5 translocations, 6 are 1+5 or 7 (not 6) while only one is T6+(?). In addition to the derived semisterile lines, another derived type with about 65% pollen abortion and a ring of 6 chromosomes attached to the nucleolus was found here at Minnesota. Intercrosses are growing in the greenhouse to determine which chromosome pair has been lost from the ring of 8 cliromosomes. Linkage tests with the («.)8 showed the following percent- ages of recombination: f - 22%; bmp - 50%, y - 16%; v_5 ~ 9%, bn ~ %%» jgl - 5%; ra - 3%, Recombination values and gene order in one T (1) ? -5 stock derived from the (*)8 are: bm 30______Pn ^»7_______ ys-T - 2%. 2* Yellow Endosperm.— One selfed ear had 112 deep yellow : 71 pale yellow : 14 white grains, a 9:6:1 ratio which may be interpret- ed as the interaction of two factors for pale yellow. Tassel-seed-4 was also segregating. The ratios for ts/( in the three classes suggest linkage of ts/, with one of the two pale yellow factors. It should be possible eventually to identify stocks for the different yellow factors by their linkage with other characters, e.g. msp for I, al_ for one chromosome 2, vg. for another, etc. 3. Chromosome 6 Linkage Studies.— A stock of ms. jsb has been established. The linkage of pb with Y is very close. Classification for suo has not been very satisfactory in material grown here at Minnesota. The data reported by me in the Coop Letter of March 23, 1937 (p. 15) indicated the order y-pl-sup, with about 8% recombination between sup and PI. It was noted there that the separation for Yy. poor. Since then Horovitz et al. (Anales Inst. Fitotecn. S. Catalina 3:37, 1941) reported a su* between Y and P I . One backcross test with F I using sup as the female parent indi- cated 15% recombination, but all the recombinations were found in the non-sugary class. One test of sup vs ms. was set up as follows: (ms + ) ( + SJ2) was crossed on a me Suo Suo stock and the progeny grown. The open pollinated ears were examined to determine the number of homozygous Sup and heterozygous sup in the normal and ms classes, from which the per cent recombination can be calculated. The method sê cis to be usable. In this case, 32.8% recombination was observed between ms and sup. These results are not satisfactory , however, since in the ms class there 'was 21.5% while in the non-ms class there was 45*4%- Intercrosses of sup •with Horovitz’s sux have not been entirely satisfactory but they seem to indicate the two are the same. Red glume collar in the tassel florets appears to show linkage with PI in certain cultures, not in others. 607 A ailky character is closely associated with antherless in the stock obtained from the Corn Coop, This silky vs X showed 16.5# of recombination, Trisomic tests for location of new factors in chromosome 6 : bag (barren stalk in a sweet corn), a new silky from a single cross, and a new stock of tinged (tn) show normal disomic ratios. The midget dwarf (mi) shows closer fit to a trisomic ratio than to disomic, although classification was not too certain, C, R, Burnham The following have assisted in the work at various periods: Gertrud Stanton, C, H. Li, T, J. Liang, and H, H, Highkin. A, Miscellaneous Linkage Tests,— For the new silky mentioned above, data from a small population suggest a linkage with pr. There is no close linkage indicated between narrow Ieuf-2 and: floury, yellow endosperm, colorle.ss aleurone. Linkage v;as reported previously between pr and 5ho - sho is closely linked with a^, nc crossovers being found in an F2 repulsion population cf 1189* T'ore was a suggestion of linkage between yellow vs. pale- yellow and trie tinged mentioned above. H* H. Highkin and C, R. Burnham 5. An "Oenothera" or Multiple Translocation Method of Establishing Homozygous Lines,— A method by which a gametic combina- tion could be made homozygous immediately should be of practical use to the plant breeder. One method, the utilization of haploids by doubling their chromosome number, has been suggested by many workers. It seems to be a feasible method in crops in rvhich pollinations can be mr.de on a large scale and genetic markers are available to aid in their recognition, A second method for obtaining such homozygous lines is one I am calling an "Oenothera" or multiple translocation method. In this method, all the chromosomes of the haploid set are to be involved in translocations in 3uch a way that the Fi of crosses with normal stocks will have at meiosis a ring containing the entire diploid number 0 1 chromosomes. Such a plant should produce two kinds of functional spores corresponding to the two parental gametic combinations of chromosomes. Among the offspring from selfing such a plant there would be the heterozygotes with the chromosome ring recognizable by high spore abor- tion; and in addition two types of normals, each homozygous for one of the two parental gametic, combinations. These two types of normals would huve normal pollen, the normal number of chromosome pairs, and could be distinguished by crossing them with standard normal stocks. 608 The normal type not carrying the translocations would constitute the homozygous line. The degree of homozygosity in these lines thus isolated depends on the amount of crossing over which has occurred at meiosis in the formation of the functional spores. Crossovers in the differential segments result for the most part in spores carrying interchanges and would be eliminated. Crossovers in the outer or interchanged arms of the chromosomes would be the ones most likely to result in recom- binations of characters between the two parental gametes* The amount of recombination may not be very large, since crossing over is usually greatly reduced in regions near the translocation points and reduced to a lesser degree in regions fartber away. It might be necessary, however, to establish several normal sub-lines from each F^ plant to eliminate, or at least to measure, heterozygosity from that source* For practical use, the multiple translocation stock would be crossed with the heterozygous source being used for new gene com- binations (e.g. a variety, or a single- or double-cross hybrid). Each F]_ plant then represents a different gametic combination from that source combined with the multiple translocation gamete, and is the starting point of a different homozygous line to be established in Selected lines thus isolated could be utilized in breeding tests similar to those used with lines heretofore established by continued inbreeaing. The fr> euency of '’superior'1 lines should correspond the frequency of "sus rior" gametes in the heterozygous population being sampled. In u;is "Oenothera" method the gametic combination is established in homozygous condition immediately* In Stadler's "aa ecr selection" method, the selected gametic combination is combined wiwh a gamete from an inbred line. Further breeding, selection and testing are necessary to isolate lines which carry at least part of the new germ plasm. The "Oenothera" method has not been tried but crosses are under way by which it is hoped to eventually produce such a multiple translocation stock in corn. The plan of procedure is to choose for crossing only those translocations involving one chromosome in common in which the breaks in this common chromosome are f-r enough apart to furnish a "differential segment*" A crossover in this segment will combine the two translocations in the same gamete. Spore abortion will undoubtedly increase as more transloca- tions are added, but it is hoped that it will not preclude dehiscence' of the anthers or the production of sufficient seeds to utilize the method. It is possible th?.t in the larger rings more of the disjunc- tions will fall into the zigzag type and thus reduce the degree of spore abortion. C. R. Burnham 609 5. Notes on the Use of Maximum Likelihood Formulae for the Calculation of a Single Recombination Value for Data From Several Sources*— (As applied by Immer and Henderson, Genetics 28:4-19-44-0* 194.3*) Two methods are available, one being to weight each value according to its standard error* The other method is to combine the separate maximum likelihood formulae for each source into one formula, place it equal to zero, and solve for a value of £ which best satisfies this equation. In using the second method as outlined, difficulties were encountered which were finally solved with Immer’s help* Two changes must be made in the method as outlined. 1* The separate maximum likelihood formulae must not be reduced by any factor common to that portion (since it is not common to the other formulae being added to make up the one combined formula)• 2. The maximum likelihood formulae as set up apply to ’ repulsion* When used for coupling, the entire formula for that portion must be multiplied by (-1) (as shovm by redifferentiating the basic equations). The maximum likelihood formulae for the various sources of data become for F2 consisting of (3:1) (3:1): 1. for ?2 repulsion; 2p = 0 For F2 coupling this is multiplied by (-1). It must also be remembered in substituting that in coupling £ is the non-recombination fraction or (1- the recombination fraction). 2. For"singly dominant" Fp plants classified into their genotypes in Fo, the formula for repulsion is: k _ 2j+k + (i+k)2£ - 0, the same as given in the p 1-p l-p̂ paper. For coupling the entire formula is multiplied by (-1)* 3. For "doubly dominant" Fg plants classified into the relative numbers of heterozygous ana homozygous geno- types, the formula for repulsion is: 2 t ; + f _ f-K _ 2(h+l) (I-2p) _ (e+f+g+h+i)2p = 0 p 1-p l-2p+2p2 2+p2 This is also the same as given in the paper. For coupling the entire formula is multiplied by (-1). 610 If linkage data from these thr^e sources are available, these formulae are"combined by addition into one maximum likelihood formula, the observed values substituted and the value of £ which best satisfies this equation is determined. The standard error to be applied to this value is calculated from the total amount of information furnished by the available data, since S.E.p where Ip is the tot*l amount of information. Ip can 7 Ip be calculated easily by the method in Mather "Measurement of Linkage m Heredity", page 68. A supplementary note to the paper in Genetics had been pro- posed by Immer* H. H. Kramer and C. R. Burnham Missouri Botanical Garden, St. Louis, Mo. and Pioneer Hi—Bred Corn Company, Johnston, Iowa Variations in Kernel Shape end Texture in Corn-Belt Maize.— Typical kernels were selected from 14,0 different inbred Lines of dent corn. These included as many of the standard inbreds such as 33-11, WF-9, etc. as could be obtained, together with some of the newer inbreds and various "sccond-cycle improvements” on elder inbreds. Care was taken to obtain healthy and well-grown ears in spite of the weakness of some of the inbreds. As representative a kernel as pos- sible was selected frwin each ear and thu variation of the entire col- lection was repeatedly examined and compared with collections of open- pollinated varieties from various parts of the New World. Much of the variation in this material, more than at first seemed possible, is accounted for by differences in the texture (hard dent, soft dent, etc.) and in the position at which the kernel shows its maximum width. The latter character varies from wedge-shaped kernels like WF-9 to broad-based, pointed ones like K 43* II - small percentage of "buckshot" and poorly developed kernels are excluded as too difficult to classify, the remainder show a clear set of transi- tional stages between these two extremes. At the cne end is the flat, wedge-shaped kernel fairly similar to many of the older open—pollinated varieties. It is widest at its apex, and allowing for the shrinkage when it dents, it is also thicker at that point. Consequently it not only tapers to the be so, it a.lso slopes to the base (i.e. the narrv...ing is in two dimensions). The kernels at the other extreme are both wide an*’ high at the base, bulging out broadly below and tapering conewise toward the apex. Between these two extremes it is possible to select a whole series of intermediates. Those about in the middle are flattish kernels, widest in the middle and also slightly thicker there. It is 611 they and the ones even less pointed which are of most interest th ini s classification. It does not seem probable that one would^have recognized what is apparently a slight degree of pointing, until ha hed seen all the intermediate types laid out in this way. Thes f ee r ao in it - kernel shapes seem to result from various intermediates bet t ww eo e nf undamentally different growth patterns,similar to some of those which have been analyzed in Cucurbits by oinnott. The kernels were then classified for texture. At the one extreme (grade 1) were a few inbreds which showed no capping of s s ot fa tr ch. In the next class were those which were capped but not pe c re -ptibly dented. Next (grade 3) were both capped and dented but without a wrinkled pericarp due to the collapse of the soft s a tr ae ra c. h Finally there was a class whose kernels were capped, dented, -nd with the pericarp distinctly wrinkled at the apex. When these grades of denting and pointing had been determine t dh e entire collection was sorted out simultaneously for both charact A e rf se w of the small kernels remained difficult to classify and th m ea ry e well be other factors such as long kernels vs. wide kernels w n he ie cd h to be considered. However this simple two-way scheme workeo s .u rprisingly well and brought similar types together« The distiibu— tion was as follows: A POINTING OF KERNEL-------- 1 - i w Widest at Widest at Widest ap IX e, x middle base 1x1 GRADE U 20 0 0 (xh O GRkDE 3 26 26 12 GRADE 2 U 2p 1 0 fr-H GRADE 1 7 11 3 IH 25 '-M Figures show No. of kernels in each class. a It will be seen that there is a fairly strong negative correlation between denting and pointing. The heavily aented kernel a sr e all widest at the apex and the less the degree cf denting the higher is the proportion of pointed kernels. After the kernels had been laid out in this way it was apparent that certain other characters were correlated with poin o tr i nw gi th denting. The association of red pericarp with pointed k w ea rs n ep la sr ticularly ccnspicious. Of these widest at the apex only p 7e rcent were so affected whereas 10 percent of the medium pointed, and 53 percent of tnese widest at the base. This may be related t h te o fact that in Mexico, the supposed ancestral home of our d c eo nr tn s, pointing of the kernels is very closely associated with p re er di carp. Red pericarp was found to have no obvious connectxon d e wn it ti hn g but blistering of the pericarp was strongly associate d de n wt ii tn hg , as well as negatively with pointing. Another feature wh ( it ch ho ugh it varies greatly in its expression) is characteristic of 612 certain inbreas, is a silvery appearance of the pericarp, apparently due to air. This showed no association with denting out was strongly correlated with pointing. After the above analysis had been made it was interesting to examine various inbred, single-cross, and open-pollinated varieties. The interaction of various factors in producing different types of dent corn is much clearer after such an examination. The production of a smooth, dimpled dent (such as characterizes OS 420 among the inbreds) is very evidently the combination of a high degree of denting with a fairly high degree of pointing. It is the pointing which shapes up the kernel and gives the ear its neat appearance. Edgar Anderson (Missouri Botanical Garden) Ray E. Snyder (Pioneer Hi-bred corn Breeding Company) New fork State Agricultural Experiment Station Geneva, New York In the early summer of 1944 Professor S. Horovitz, of the Phytotechnical Institute of Santa Catalina, of Argentina, sent me some seeds of his new sugary (su^. He and coworkers reported this new sugary in the Analos del Instituto Fitotecnico de Santa Catalina (j-941) 3:37-44. He says there that it is on chromosome 6, and that it interacts with sup to make sup dominant. The sux was crossed with sup (the inbred, P51) soon as possible; the Fp seeds were starchy. Last rummer I grew the F]_ anc1 selfed four plants. Five classes of seeds appeared: starchy; sux, which is waxy looking but stains black with I2KI; a smooth-sugary seed which is aented and translucent, but not wrinkled; ordinary sugary; and super—sugary (Horovitz1s name), which is more wrinkled than ordinary sugary. Not only was there an extra class, but two the four ears fit an extraordinary ratio, as shown below: 87 (H) (x) 87 (3) (x) 87B (2) (x) 87B (3) (x) Obs. Ratio Calc. Obs. Ratio Calc. Starchy 224' 8 230.0 312 9 299.5 Sugary - x 61 2 57.5 56 2 66.6 Smooth sugary 35 1 28.8 35 1 33-3 Sugary - 1 83 3 86.3 93 3 100.0 Supersugary 57 2 57.5 37 1 33.3 x2 = 1.84 x2 = 3#20 613 If the four ears are assumed to be the same and are lumped together, the total counts do not fit either ratio, but are nearer to 8-l/2: 2:1:3:1-1/2, The classification of the various kinds of kernels is clear except between sugary and supersugary. John Shafer, Jr. Pioneer Hi-Bred Corn Company, Pioneer Laboratory, Johnson, Iowa The determination of chromosome knob numbers in the more important inbred lines of Corn Belt maize was started in the summer of 1945, of which a preliminary account may be made at this time. To date, approximately thirty inbred lines of dent corn, twelve open pollinated or inbred strains of popcorn, and five North American flints have been examined. Although these numbers are relatively small when compared with the total amount of material available, the results obtained reveal some rather interesting facts. Among the thirty dent corn inbreds studied, knob numbers are found to range from two to nine with a frequency distribution as indicated in figure (1). Knob numbers appear to be correlated with certain morphological characters of the oar. For example, those lines possessing high knob numbers have, in general, a more compressed Ixise, more tapered ears, and higher numbers of rows of kernels than those with low numbers. There is also some evidence indicating that irregular rowing is associated with high knob number. Among the popcorn strains examined, all were found to possess median knob numbers (4-6). The most interesting observation encountered occurred in the 8-10 rowed North American flints which were found to be knobless or nearly so. Of the five lines ex- amined, four were knobless and one contained a single xnob. These data, it will be noted, are not entirely in agreement with what one would expect on the basis of the tripsacum hypothesis* William L. Brown Knob Numoer Fig. 1 614 University of S. Paulo, H * pt * «'Luz de Queiroz" School of Agriculture, S. Paulo, Brazi.l1 1. The al gene is very closely linked to lgj a t ch ce o rf do il nl go w ti on g data obtained in F2 (repulsion): Pedigree NO, + + + Ml al + al l£ 754- 1 108 67 46 0 - 4 151 58 85 1 - 42 0 - 65 103 45131 62 54 1 - 7 196 88 106 0 - 8 114 57 39 0 - 9 ISO 80 87 0 >11 118 46 56 1 >18 132 63 47 1 TOTAL 1233 563 565 4 Crosses involving al, lgl and were made this summer (1%5- i On c to or bd ee rr ) to get the position of al in relation to lgl and £ ± 2 m chromosome 2. 2, One ear segregating for £3 showed female elidin f 'o r t it oh ni s condition. The cross made was %ml3l3l5%5 x XTOl';H3Z5T5 and the expected ratio 1 orange yi (2X li li lo 1X 3i 2, 3 )l lXl : liii) changed to 1 — o 3sr an •ge : 1 white (81 oia o nr ga en g we e es de se d .s sowed were selfed and gave in c aa ls les ears segregating for 9 orange : 7 white. Th n eo rm wa hil t ep la En ^ts s wh gi avc eh when selfed produced ears segregating lor albescent seedlings. 3 Material received from Dr. A. M. Brunson was s i os w en do w a nb de ing crossed with several testers. The wh ; ia tv e€ . sa el eb di sn o a lwp al ya sn ts and the dual effect of this mutation c a (l pl re od v iy sx i) o ns ae le lm ys to me in favor of the hypothesis that is identical with ul* Seeds received from Dr. Merle T. Jenkins were sowe o d nl ay n d the "dark yellow" germinated. The "lemon yellow" s ii s mi vl ea rr y to some Yi stocks I have and in my opinion o mn ul sy t " by ee l cl ao lw l" e di n order not to confuse it with the "lemon t yo e lt lh oe w '-y e dl ul eo w aleurone color. Dr. Jenkins’ ratio (o 3r a dng ae r) K y: e 1 oy *ellow is identical with th .t I obtained i s nt r Ba ri an zs i li( aM nai ze Nows Letter 17:1943 and Amer. Nat. t he 7 9.g 1e 8n 7e - 1p 9r ^o ,d uc 19i 4n 5g ; t -h *e n b difference orange : yellow I called provisi Y on n. a llS ye veral crosses are now being made in order to o f t rY y ta hn ed lod to c as te ie o ni ts interrelations with Dr. Jenkins gene m chromo- some 7. 615 5. My working hypothesis on the yellow-orange endosperm is now as follows: (a) Several Y-genes with complementary effect, similar tc the A1A2A3C R series for aleurone color. Of the Y-series, the known genes are Yi in chromosome 6, Yo in chromosome 2 and probably of Dr. Brunson, chromosome unknown. The y* condition is lethal and the produces albescent seedlings (£l oeneJ. (b) The ic gene, isolated from Bra m ze in lit aa nr y st to r al ix ns in i s p cr oo md pu lc ei -ng yellow endosperm but i i sn dependent of I3 and so, also, of the other Y genes of the series. (c) The Yn gene (D=determiner) producing o tr ha en g de i fference 2 yellow, found in Brazilian material and extremely influence! by modifiers. Similar gene found recently by Dr. Jenkins in chromosome 7. • (d) The Bn gene in chromosome 7, producing yellow o nl py i* gT mn e ntthe aleurone layer. These ’-lemon yellow’ seeds are detectable in stocks lacking one of the cumple mentary Y—genes for endosperm color. 6. The ratio 15 orange : 1 white was r e ss eu cl ut ri en dg if nr o om n ea ec ar ro ss of Brazilian strains ^ange x_Ai.c, pl Ta hn et s obtained from the orange seeds were selfed and m 4& . following results obtained; Ears pure for orange 23 Ears segregating 3 orange : i white 14 Ears segregating 15 orange : 1 white 9 As the mutation from the recessive to the dominant condition o ir so b nc ob ti e and the ratio of ears obtained not in p fe an vd oe rn t o fg e Unes j , ins do em e of the plants obtained from 1 t5 he o1 ars segregating : were fixed and will be checked cytologic^lly. 7, The location of the Yc S c er no 0s s in fv °o il nv ci ng a tester , 7o °f Dr. Randolph’s covering c h mr oo sm to s oo fm e ts h eg ave the following results In two ears obtained frcm the same plant; Ratio 36 9 19 Orange Yellow White + Pedigree NO. (^l“ (?1- Y3y3Y5~) Lemon yellow + sui + su^ + sui 179A-1 231 78 69 15 109 48 179A-2 112 28 34 13 37 16 TOTAL 343 106 103 28 146 64 616 The segregation for sup is normal. The yellow seeds not sup, where the classification was good, were sowed giving most of them al plants. Few plants not al came from Bn seeds since this gene was present in Dr. Randolph's stock. Segregation for bmo and crp was normal and only one plant seemed to be jgx and none R». Proper tests for chromo- some 10 are being prepared but we don’t know if plant character markers combinod with al will be easy to classify- 3. Markers in all chromosomes and in back—grouna favorable for the State of S. Paulo (Brazil) and probably for South America conditions are now available. Triscmic stocks for chromosomes 2 to 10 segregating recessive genes in the respective cucuosemes are now available and the tiisomic segregation will be checked again this Slimmer. The transference of deficiencies in chromosomes 3>4>5>b, and 9 (material from Dr. Stadler) to Brazilian strains is being continued. 9. Treatment of seedlings by artificial light during 15 days and four hours every day, in era very early and other very late stocks did not show significant difference flowering when compared with plants that did not receive treatment. /’Iso, I'O^s with cu~y~ light reduced to 10 hours every dry, during 15 days, .red normally when compared with the control. E. L-. G saner United States Department of Agriculture, and Cornell University, Ithaca, N. Y. 1. In the preceding News Letter it was reported that tetr&ploid hybrids of Tripsacum and maize had been produced from exper- imental autotetrnploids of maize pollinated by a natural autotetrap16id Tripsacum from the Eastern United States. Repeated attempts to obtain seed from these hybrids by backcfossing to the parents failed. Since they produced only aborted pollen, with the possible exception of c* very few grains partly filled with reserve food material, extensive attempts to self or sib cross these hybrids were not made. But very recently it was noted that a few partly developed seeds had formed on two of the 13 hybrid plants being wintered over in the greenhouse. These seeds apparently resulted from sib-crossing. By culturing the ̂ embryos of these seeds four seedlings have been obtained from which it may be possible to procure additional progenies. During 1945 an initial attempt was made to repeat the cross of diploid corn and diploid Tripsacum made by Mangelsdorf and Reeves in 1930. A diploid Tripsacum from Kansas was used rather than the Texas form used by Mangelsdorf and Reeves. Very little difficulty^ was experienced in making the cross; 35 hybrids each with 23 somatic chromosomes were produced by pollinating 5b ear shoots of corn. ihe comparable frequency obtained by Mangelsdorf and Reeves was « C ar rco bp fD ,i v. Program, p. 19-20 (Abstract). 1946. H. H. Smith 624 Ill SEED STOCKS PROPAGATED A complete inventory of material L e ot nt e hr a nH d wa an sd pa rd ed si et ni to en da l i l nis tt os were given in H a m much ag there appear to have. t -h e a cC ;o mS op d unnecessary to present mate “ rT ial C duri ng “ tht ea merely"involvud T " Z thed gro wit nh gT ^ oe fn e cus lT ti uo r^ el s d f rn oo mt old 1 be 3 lost. H% owev’ et ro , o Du rt .c r Ho us rs r awe ye d bs egg ae nn et ii nc m a st te or ci ka sl ta ov a ii nl ha rb ol de s , in * m £ore * vi £go £rou £s c co on mbt ii nn au te id o na sn .a a Tn h um - ber - of suc g hr o cs os m bh ia ns a ta il os no s been ni.de in the transfer oi marker s gt .o nc ek ss. R. L. 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i d o d CO p p p P P P P PO C O P P P P W W PCOk P 3-°0 d d cd I 0 O to a cd o a0 H O 02 C\J oj c\! W O i f ' i W C M O J W O l O i N C M N C M •■Ha P to CO d CA •oH p cd cd cod P cd P O P cd P cd p o p o cd p O -4t f 7 -4j ^ 4t UA £ P1 On CA P o rH < » I I l 4 4 I 1 1 1 02 02 02 02 02 02 Cx2 CO cd d E-t 632 California Institute of Technology, Pasadena, California Anderson Columbia University New York, New York 1. A new mutable gene. Mutable alleles have been found at the P, Bt, and Wx loci. These mutable alleles may be described as recessives with a high mutation rate to the dominant allele. In addition there is the genically induced mutability of recessive a by the Dt gene. The effect of 3h on recessive c_ probably belongs in this category. A new type of mutable allele has recently been found. A dominant A allele mutates with high frequency in both somatic and germinal tissue to an intermediate allele producing light aleurone color and red—brownish plant color, The effect on pericarp color has not yet been determined. An example of the mutation rate of this mutable A. allele (designated A[̂ ) is as follows: The cross of a x  , gave 74- kernels with self-colored aleurone, 61 kernels mosaic for deep and light colored aleurone, and 24 with light colored aleurone. At least two different intermediate alleles, differing in intensity of color in aleurone and plant, have been found. 2. Directed segregation. A derived strain from a complex translocation involving chromosomes 5 and 3 has the following constitution: Nine normal bivalents, including chromosome 5, and a chain of three consisting of a normal chromosome 3> a short arm, and a long arm of chromosome 3 • Yfhen this chain of three is present in plants with a certain genetic background, the orientation of the chain on the metaphase I spindle is approximately randomfi.e., orientation of the chain leading to alternate segregation of the three members and giving euploid combinations occurs in 50 per cent of the P.M.C., while a linear orientation leading to aneuploid gametes occurs in 50 Par_ cent of the P.M.C. In other strains, differing in genetic modifiers from the above, the orientation of the chain is such that in about 95 per cent of the cells the normal chromosome 3 passes to one pole while the other two members of the chain pass together to the other pole. Here we apparently have a case of genic control of orienta- tion, and hence segregation. This finding is of interest in con- nection with the breeding behavior of Oenothera translocations. 3* Maize strains with II bivalents. From the translocation mentioned above it has been possi- ble to obtain plants with 11 pairs of chromosomes. They carry no duplication of genetically active chromatin. This increase In chromosome number was a consequence of the breaking of the cen- tromere of chromosome 3 into two portions with both the short and long arms receiving part of the parental centromere. M. M. Rhoades 633 New allele of Ga^ on chromosome 4. In the course of studies on a new chlorophyll striping character, a super—allele of Gu-̂ on chromosome 4» was founa. This allele, Ga , is dominant over Ga» Small ga pollen does not function on Ga*̂ siak even in the absence of competition with Ga or Gas pollen. Out of 14- such crosses only one seed developed on one ear. The other 13 ears were completely devoid of seeds. This is interesting in view of the fact that ga pollen does function on Ga silk when there is no competition with Ga pollen. Selfing of plants heterozygous for Ga and Gas using sugary as a marker, Ga su/Gas Su, showed that Gas pollen functions in the production of ap- proximately 66 per cent of the kernels when competing on Ga° silk. This super-allele appears to be independent of the striping. Drew Schwartz Studies with mutable waxy. An allele at the waxy locus (wxm)> which mutates with a high^ frequency to Wx in both endosperm and germinal tissue, is under investi- gation. This allele is intermediate between Wx and wxs; Wxwyf plants segregate approximately 3 Wxtl wx111; and wxmwx° plants approximately 3 vfxm:1 wxs. (Ratios deviate from 3:1 in some cases due to germinal mutations.) Typically, a wxmwxs plant when seifed gives three classes of kernels: About l/4 waxy, less than 3/4 mosaic (waxy with various sized spots of normal starch), and a variable number (often 5-20 per cent) of kernels with normal starch endosperm. The most readily observable mutation both somatically ana germinally is from wxm to Wx. Mutation rate comparisons made between different stocks by counting the numbers of Wx kernels- produced in crosses wxr% x ra backcrossed or seifed, indicate differences of the follow- ing order of magnitude: VT̂ m Wx wxs % Wx S-43-12 seifed 140 ■ 4 ■ 1 2,7?o S-47-2 x wxs 199 41 17.0 9903-10 seifed 63 24 27.5 9903-4 seifed 53 34 39.0 The mutable allele probably also mutates to wxs« Four ears from a cross wx ŵx^ x wx^wx^ threw 5*3 pan cent wxp seed* A mosaic kernel when grown and seifed gave the phenotypic ratio 29 Wjc:212 wx , 19 v^s _ the 29 Wx and 19 wx3 kernels arising by mutation. These seeds are being grown now to establish their genotype. In a few stocks, kernels have been found consisting entirely of normal starch except for many small scattered waxy spots. Sj.nce in 634 these cases the rest of the ear bore all normal starch kernels (Wx by mutation), these spotted kernels may represent reverse somatic mutations of a somewhat unstable Wx1 allele back to wx. A study of the distribution of Wx and wx pollen grains in alcohol preserved tassels from wxmwxm plants (Wx grains stain blue and waxy stain red with weak IKI) indicates that mutations may occur so early in tassel development as to affect an entire branch, or even a few neigh- boring branches. On the other hand, some branches carry anthers segre- gating in varying ratios, indicating later mutations. Mapping of ears from crosses wxmwxm x wxswxs has not revealed any sectored pattern as yet. Ruth Sager Connecticut Agricultural Experiment Station New Haven, Connecticut Varieties of corn groY/n in the Northeast and in the Middle West at the same latitude are noticeably taller in the East. Several environ- mental conditions are involved in this growth difference, principally light intensity and temperature. Plants of many species, including maize, grown under tobacco shade cloth are significantly taller and broader in leaf than plants from the same lots of seed grown in full sunlight. ^Under the cloth shade the temperature is the same as outside but the humidity is higher and the light intensity is lower. The same effect is noticed in the field where short-stalked varieties of corn are grov/n in single rows between taller varieties. 7/here there is a v;ide alley between ranges the plants at the ends of the rows are shorter than those^in the center of the rov/s, the plants graduating in height. Here humidity ana tempera- ture are the same but light intensity varies. Some corn seedlings started in the greenhouse ana set outaoors were shorter at maturity than plants from the same seed started outdoors. This indicated that temperature in the early stages of^grovrbh had an effect* To test this, seeds of a uniform, vigorous, first generation^ hybrid'(Wf9 x PS) were germinated in an incubator at about 30 C, until the shoots and roots Y/ere from one fourth to one half inch long,^ Three different lots of sprouted seedlings, were held at 4-0, 50 and 60 C. for^ one hour. They were then planted in pots and left in the greenhouse until it was certain the plants would grow. They were then set in the field alongside plants from the same lot of seed sovm in the open ground at the same time the treated seedlings wTere started in the incubator. Some of the treated seedlings died but enough were started in each lot and later thinned to give an even stand of plants in the field. All three lots of heat-treated seedlings were shorter in height, less vigorous in growth throughout the season and later in flowering than the treated plants. All lots grew to full maturity and were measured after grovrth had ceased. The results are: Control 101: 40 C, 87; 50° C. 89; 60° C. 93 inches in height. The differences between the three 635 temperature treatments are small. All three averaged 90 compared to 101 inches in height for the control. The result that was not anticipated was the pollen sterility- in all treated lots. Normal tassels were produced with well-developed florets but the anthers were small and shriveled and for the most part remained enclosed in the glumes. In view of the fact that high tempera- tures sterilize the male germ cells in animals, from amphibians to mam- mals, these results are highly significant. This influence on growth is an anti-vernalization effect and may have wide usefulness in the produc- tion of hybrid seed especially if shown by other plants as well as maize. D. F. Jones A second "Teopod" mutation. Another mutation to Teopod or a similar character, has occurred. This mutant was discovered by Dr. Bailey Pepper of the New Jersey Experiment Station in a field of sweet corn growing in New Jersey, We obtained seed from Dr. C. M. Kaensler of the New Jersey Station. It was grown under the name of "Corn Grass" because it was much more like a grass than normal corn. The blades of the leaves are narrow and there are many tillers giving a grassy appearance. In the field the plants do not exceed three feet in height and look much less like normal corn than the Teopod of Lindstrom. However until the two stocks have been tested by crossing it is not possible to state whether they are allelic. These tests will be made in 1947. The "second Teopod" was first grown in Connecticut in 1945. Seed from the mutant produced two kinds of plants, normal and Teopod, in approximately equal numbers. The normal plants were recessive. Open- pollinated seed from the Teopod plants gave in 1946 a 1:1 ratio for normal and Teopod. In the field in 1945 and 1946 no tassels of any kind ?/ere produced. The stock -has been maintained by backerossing to normal corn. In the 1946-1947 greenhouse, crop grown under a shorter day, tassels with apparently good pollen have been produced. The "Teopod" reported here makes many brace roots beneath the leaf sheaths. Some of these grow to be several inches in length. It occurred to us we might propagate these asexually and an attempt was made. The cut stalks rooted and lived for several weeks. Had the attempt been made earlier in the summer, it is possible they might have been successful. One is forced to speculate whether mutations to such bizarre types as Teopod may have any bearing on the origin of corn. If a single gene can change the habit of a corn plant so completely, might not a reverse mutation have originally occurred to give us normal corn ? Possibly the ancestor of maize may have been something more like one of the Teopods, 7/. R. Singleton 636 Cornell University Itheca, New York The relation of plant colors to total dry weight in maize, A number of years ago Brink (Jour. Amer. Soc. Agron. 26; 697- 703, 1934-) reported the relative yielding capacity of four different anthocyanin plant-color types, namely, purple A B PI, sun red A B pi, dilute purple A b Pi, and dilute sun red A b pi. The stocks were so bred that all four classes occurred with approximately equal numbers in each of the 11 families involved in the test and so that the residual genotypes of the four color classes were approximately the same. Some- what more than 3500 plants were observed and yields were reported as average dry weight of ears per plant in pounds as follows; Purple .133» sun red .569* dilute purple .561, dilute sun red .511. Thus dilute sun red, the prevailing color type of the country, yielded significantly more than purple and both sun red and dilute purple significantly more than dilute sun red. The writer has made similar tests, using total dry weight of plant as the criterion of yield. The genes b and pdL were derived from two dilute sun red (A b pi) inbhed dent lines and their dominant alleles from several genetic stocks, including purple A 3 PI, brown a B PI, and reddish brown a£ B PI. Each of these genetic stocks was crossed with each dilute sun red inbred and purple plants of the resulting progenies were backcrossed from one to three times with the same or the alternate inbred. Some of the cultures, therefore, were little if any more vigorous than the inbred lines and some showed marked heterosis. The four color types of any one culture, however, were comparable and occurred in approximately equal numbers. In table 1 are shown the average dry weights per plant in grans for the several color types of each of 14. cultures. Table 1 Number Culture of Mean dry weight per \ lant number plants B PI A B pi A b PI A b pi 1 90 142 111 98 n o 2 76 129 132 129 n o 3 91 165 163 150 145 4 92 133 145 145 127 5 93 206 217 229 184 6 73 78 82 118 78 7 96 204 229 222 230 8 89 161 162 146 150 9 89 118 103 122 104 10 89 187 207 227 222 11 74- 117 122 115 117 12 76 68 88 77 74 13 96 202 181 186 199 H 94- 186 172 185 203 Total 1218 Average of mean 150 dry weights 151 153 147 637 In addition to backcrossing heterozygous purple plants of table 1, certain sun red and dilute purple plants were backerossed with one or other of the same dilute sun red inbreds. Results -are shown in table 2. Table 2 Number Culture of Mean dry weight per plant number plants A B pi A b pi A b PI A b pi 15 76 143 110 16 89 129 124 17 86 128 134 13 80 123 n o 19 82 132 128 20 79 108 103 21 91 -222 238 22 95 195 192 23 94 201 194 24- 95 195 217 25 33 120 106 26 83 72 75 27 92 259 251 23 92 206 201 Total 1222 Average of mean dry weights 160 156 29 84 143 146 30 91 149 152 31 89 166 153 32 72 136 113 33 75 157 113 34 80 140 120 35 74 126 118 36 61 71 85 37 92 253 254 3S 94 199 199 39 72 196 171 40 31 202 184 41 26 215 209 Total 941 Average of mean 166 dry weights 155 638 From the results presented in table 1, it is obvious that pur- ple plants were not appreciably less in dry weight than sun red and dilute purple plants. The dilute sun red plants were lowest in dry weight but not markedly less than the other three color types. The results given in table 2 were similar to those of table 1. In one lot of cultures, dilute sun red plants were slightly less in weight than sun red ones. In the second lot of cultures, dilute sun red again was less in weight than dilute purple; and the difference here is greater than in the other tests. On the whole and in so far as the results here reported are concerned, it can be said that in segregating cultures, dilute sun red plants were slightly less in total dry weight than were plants of the other color types. Whether or not the fact has any significance, it should be remembered that, in all these tests, comparisons have been made between homozygous dilute sun red and heterozygous purple, sun red, and dilute purple. Among genes other than B and PI that are related to plant colors of maize, the A _a pair is of fundamental importance. In most Instances, only in the presence of dominant A do anthocyanin pigments develop. Where A results in purple or red, its recessive alleles usually give brown or have no appreciable effect on color, Accordingly several tests have been made of the possible influence of A and of some of its alleles on dry weight of plant. Certain colorless (green) types were crossed with the two dilute sun red inbreds used in the tests noted above. The Fp plants were backcrossed to-the colorless parent. Three sets of cultures were grown from the following crosses: (a B pi x A b pi) x a B pi, (a b PI x A k. Pi) * a. b PI, and (a b pi x A b pi) x a b pi. In each set of cultures, two color types were represented. The results are given in table 3. The records of table 3 reveal small but not consistent differ- ences ixi total dry weight of plant between colored and colorless individ- uals of the several cultures. In averages of mean dry weights, sun red plants were about five per cent lighter than the corresponding colorless ones, while dilute purple and dilute sun red plants were heavier than their colorless sibs by six and three per cent, respectively. With the genotypic backgrounds here involved, there was relatively little effect of A and of its recessive allele a. on total dry weight of plant. There remains to be considered a possible difference between the influence of A and of some of its recessive alleles when the background genotype contains both dominant 3 and dominant Pl,; In one lot of tests purple A B_ PI was crossed with brown _a B PI and backcrossed once with the same brown. The results are recorded in the first section of table Another allele of A, namely, aP, gives a reddish bro?/n plant when in com- bination with B and PI. Reddish brown was crossed with one of the two dilute sun red inbreds and the purple plants resulting were backcrossed once or twice with the same reddish brown, Recessive a2 with B and PI gives brown plant color. This brown was crossed with reddish brown and the resulting purple Fp plants were backcrossed with reddish brown. The genotypes concerned here are as follows: (A a2 B PI x rP A2 B Pi) x al A2 B P^, All these progenies, segregating purple and reddish brown, are recorded in the second section of table J+, 639 Table 3 Number Culture -of Me£an dry weight per plant number plants A B pi a B pi A b PI a b PI A b pi a b pi 42 83 150 157 43 73 158 138 44 88 162 163 45 70 176 180 46 81 159 169 47 88 182 215 48 78 210 221 49 52 189 227 50 65 184 196 51 57 188 193 Total 735 Average of mean 176 136 dry t:-eights 52 47 144 130 53 37 171 170 54 42 143 105 55 69 186 175 56 73 171 163 57 76 165 167 58 79 169 163 59 70 193 158 60 70 166 183 61 70 174 169 Total 633 Average of mean 168 158 dry weights 62 71 185 195 63 63 180 170 64 37 181 155 65 60 146 158 66 57 171 174 67 48 172 162 68 51 146 137 69 57 132 139 70 46 181 159 71 59 167 I64 Total 549 Average of mean dry weights 166 161 640 Table 4 Number Culture of Mean orv weight per plant number plants A B PI a B PI A B PI a£ B PI A2 B PI a2 B PI 72 48 150 134 73 80 95 75 74 83 109 96 75 80 97 88 Total 291 Average of mean 98 dry weights 113 76 61 126 96 77 61 119 81 78 71 111 84 79 61 115 85 80 49 156 138 81 40 128 115 82 81 112 89 83 63 142 114 84 56 126 122 85 66 140 101 86 76 157 106 Total 685 Average of mean- 130 dry weights 103 87 59 167 141 88 68 170 128 89 41 173 147 90 45 162 119 91 75 154 127 92 67 163 117 93 83 171 124 94 92 136 135 95 73 140 103 96 77 117 95 97 73 207 182 98 67 140 91 99 78 172 131 Total 898 Average of mean 126 dry weights. 159 641 Brown plants of the genotype A a2 B PI were crossed with one of the dilute sun red inbreds, with purple, and with reddish brown. In all instances the resulting F^ purple plants ?irere backcrossed with A a2 B PI. Here then the brown plant color is conditioned not by an allele of A but by an allele of A2, The cultures involving A2 and a2 are listed in the third section of table A» Cultures segregating for purple and brown plant color, as shown in table A> whether the brown color is conditioned by a., or its allele aP, or by a gene of a different chromosome a2, all exhibit consistent results. The averages of the mean dry weights are greater in each of the three lots of cultures by from 15 to 26 per cent for the purple than for the brown plants. Moreover in each of the 28 cultures of table A without a single exception, the purple plants are heavier than the brown ones. Since for one of the genes conditioning brown plant color, namely, _a, no consistent effect on v/eight was found when A and a_ were combined with 13 pi, Id PI, and b pi (table 3), it seems reasonable to assume that the lighter weight of brown plants conditioned by _a, sP, or a2 in contrast with purple plants conditioned by the dominant alleles of these genes, results from some deleterious effect of the brown pigments in the physiology of the plant, rather than from a direct effect of the recessive genes or of growth factors closely linked with them. R. A. Emerson Florida Agricultural Experiment Station Gainesville, Florida Mendelian interpretation of offspring-parent regressions. Dr. K. Mather on his recent visit to this country discussed some extensions of methods proposed by Fisher, Immer and Tedin, (Genetic 1932), for estimation of dominance bias in quantitative inheritance. My own attack in the last News Letter is also an extension of the same. My approach seems to have some advantages from employing highly inbred or homozygous parents. Uncertainty on linkage effects is largely eliminated. Dominance does not reduce correlation between phenotypes of homozygous parents and the gametes they produce. I have found no partic- ular advantage in requiring equal frequency of a and A alleles by con- fining study to populations which stem from a single selfed heterozygote in each case. Samples of homozygous lines, selected or otherwise, seem to be satisfactory. If all of this be true the method must have a wide utility and may be presented again from more of a Mendelian and less of a mathematical viewpoint, If the heterozygote aAbBcCdD is crossed to the multiple reces- sive tester aabbccdd, testcross progeny may be classified on kinds and frequencies of four distinct qualitative characters to obtain a reflected view-of dominant alleles in gametes of the heterozygote. This is the 642 method of classical genetics. It has been seldom noted here that regres- sion of number of plus characters in testcross progeny on number of dominant alleles in parent gamete is 1.0. Every plus allele in a gamete provides a plus character in the zygote, regardless of linkage. The top dominant AABBCCDD is clearly worthless as a tester. Offspring-parent regression is zero. Intermediate testers are efficient in inverse proportion to the number or proportion of loci of AA type. Thus if testers in general are of aa type at one half of the loci which are heterozygous in the Fq to be analyzed, a dominant allele in Fq gametes will provide a dominant character in testcross progeny in one half of the cases. In the other half the dominant character is always provided by the tester and a dominant allele in the Fp gamete can add nothing more, Regression is one half. Reduction of regression by dominant genes in the tester is purely a dominance effect. This dominance effect is reduced one half by selfing the testcrosses. It hardly seems necessary to labor with the transfer of these concepts to the general field of multigenic inheritance where effects of the several genes combine in a single quantitative measure, and where dominance is taken into account quantitatively. In the former case, concern is primarily with frequencies. Basic effects of genes and dom- inance effects are both tacitly defined as unity throughout. In the latter case the two effects must be defined separately and quantitatively. We cannot assume that either is unity since we are concerned with degree of expression, not with just whether the character is or is not expressed. In my attack the array of Fj gametes is replaced with an array of gametes from an array of homozygous parents. The purpose is no longer to obtain a reflected picture of the gametic array. That array is already revealed in the array of homozygous parents. The purpose now is to esti- mate regressions of testcross progeny on gamete or homozygous parent with different testers. If both the bottom recessive and top dominant were available as testers, decline in regression from one case to the other would reveal directly the average degree of dominance. But neither of those two testers is likely to be available in multigenic cases. We are restricted to a study of regression relations with such testers as we may be able to develop. For quantitative definitions of basic gene effects and dominance effects we may well employ the general scheme of Fisher, et al (1932) which is essentially that of Fisher in his 1918 paper on correlation be- tween relatives, and of Mather on his recent visit. If the basic, pheno- typic effect of substituting A for a is ,fd^? phenotypes of aa, aA, AA are 0, d, 2d. The heterozygote is strictly intermediate. But if there is in addition an interaction of a with A to provide also a dominance effect ,Tkd!’, the phenotypes are 0, d+kd, 2d. These quantities are deviations from a working origin at aa. Deviation of the heterozygote from strict intermediacy is kd, (h in the notation of Fisher, et al). For a multip* le set of g ̂enes a-, A1 -_l. , a0'Ad,0 - - - an^ nA. we may as well let d and kd be average values for the several loci. Then if gene action is additive each genotype is evaluated (estimated) by summing the 643 \ H . several d’s and kd's, The simplest case is n =• 2. The checkerboard frame is | A d 2dA 3A d2 3d Adj 2kd kd kd 0 d 2d 2d 3d alA2 kd 2kd • 0 kd 2d i A-, a, d 2d 2d 3d kd 0 2kd kd i 0 0 d 2d ala2 0 kd kd 2kd ala2 Ala2 alA2 A1A2 0 2d A d Table 1 Phenotypes of the 3 parent classes are written on the margins along with the gametes of each class. Phenotypes alone are written in interior cells for offspring. It may be desirable in teaching to write genotypes also in the ce3.1s and to eVaj.uate some of them by counting a d for each A allele and a kd for each aA locus or each interaction of unlike alleles. It may also be desirable to write genotypes of parents and evaluate them, noting absence of dominance effects. Table 1 is a simple regression surface. Our avowed purpose is to study the effect of k on the shape of the surface that we may interpret shapes of data surfaces in terms of k, average degree of dominance. In practice the homozygotes A2A2 anĉ A1A1 a2a2 are orĉ na” rily indistinguishable. This means that the two center columns and two center rows of table 1 may as well be pooled to conform with the situation of data on a quantitative character. Pooling provides, 644 2d 3d Ad 2k d kd 0 P2 d 2d 3d kd kd kd 0 d 2d 0 kd 2kd 0 2d 4-d Table 2 Note that the entry in the central cell, e.g., of table 2 is the mean of the four central cells of table 1. It is the predicted (average) result of crosses of homozygotes of the types indicated on the margins. Deviations of the four crosses from the mean are deviations from regression due entirely to dominance, to variations in degree of hetero- zygosity, specific combining ability. These variations are not predict- able from data on the parents. The teacher should write frequency dis- tributions of individual crosses in each cell of table 2 along with the means given here. Note further that, while tables 1 and 2 represent two-factor checkerboards of classical genetics with gametes of Fq recorded on the margins and F2 phenotypes in interior cells, the view here is arrays of homozygous lines on the margins with Fq phenotypes of crosses of such lines in cells of the tables. Subsequently, interior values will be re- ferred to as FqS in agreement with modern corn breeding practice. The two situations are strictly analogous only when a and A are equally frequent in the sample of homozygous parents. If table 2 is expanded to include many loci, parent values are 0, 2d, Ad, - - - - 2nd, A statement of the mean Fq of any cell in terms of parent values would be the general regression function of Fq on Pq and and Pp. The solution of this problem was given in the previous News Letter. The mean of any cell in a table of the type of table 2, may be calculated by solving a smaller checkerboard. Detailed arrays of gametes of the two parent types are written on the margins. But this is merely taking the product of two gametic arrays, a fundamental principle of Mendelism. Hence, if u and w are the proportions of loci AA in P-, and Po respectively, gam- etic arrays are represented in general by (1—u)a t uA and (l~w)a + wA. In all of the crosses of Pq type parents x P2 type parents together, expecta- tions are (1-u)(l-w)aa, (u(l-w) + w(l-u)J aA, uwAA. The sum- of these three proportions, each multiplied by n and by the respective phenotypes 0, d+kd, 2d, is the expected increment of mean F-j over the multiple reces- sive T, Making the substitutions u * (Pq-T)/2nd and w = (P2~T)/2nd provides the desired function. 645 The concept u •= (Pq-T)/2nd might be presented effectively to a class by laying off an arbitrary scale to represent the range of phenotype from t_________ »___________________ ______t T (2nd+T) bottom recessive to top dominant. The scheme is to count 2d for each locus AA as the increment above T, hence, 2nd where all n loci are AA. The position of any homozygote P-̂ on this scale reveals directly the pro- portion of loci AA in P^, u - (Pp-T)/2nd. The purpose of T is to adjust for the possibility that the phenotype of the bottom recessive is not zero on the data scale. It is instructive to verify from table 2 results reported last year. The left column may represent a series of hybrids having a common parent P-j , the tester, which is aa at each locus. Lines being tested are represented on the parallel margin as different values of the variable P2 . It is clear that if the tester is completely recessive, every substitution of AA for aa in P2 will provide a substitution of aA for aa in Fq. Re- gression of Fp on P2 is (aA-aa)/(AA-a&) or (one basic gene effect plus one dominance effect)/(two basic effects) or (l+k)/2. Note that the increment from one cell to the next, left column of table 2, is d+kd and that the corresponding increment in the P2 column is 2d. The ratio is (l+k)/2. When P] is aa throughout Pq-T = 0. Substitute In last year’s formula for bp to obtain bp - (l+k)/2, if Pq-T - 0. Similarly from the right column of table 2, bp. = (l—k)/2, when F1 is AA throughout, (P-,-T) = 2nd. Expansion of table 2 to include many loci will not provide different results. If, as in most actual cases, some proportion u of the loci of Pq is AA and 1-u is aa, the weighted mean increment of F^is fn(l-u)(d+kd) + nu(d~kd)1 /n. Or the weighted mean of slopes is (l-u)(l+k)/2 + u(l-k)/2 = (l+k)/2 -uk. Substituting u - (Fq~T)/2nd, bp = (l+k)/2 - (k/2nd)(Pq-T). If bp is (l+k)/2 In the left column of table 2 and (l-k)/2 in the right column the increment of bp across the table is 0 l-k) - (l+k)j /2 = ~k. The concurrent increment of u is 1, and of Fq It is 2nd. Re- gression of bp on u is -k and on Pq it is -k/2nd, as the formula bp ~ (l+k)/2 - (k/2nd)(Pq~T) expressly states. Thus, the values reported last year may be verified and their interpretations clarified by direct inspection of table 2* If it Is not immediately obvious that the regression estimates are unaffected by linkage and by relative frequencies of a and A alleles, except as noted, the student may need to work out some specific examples with numerical values assigned to d, kd, q, and per cent crossover and calculate regressions by machine formulas as well as by direct substitu- tion in present formulas. 646 It is also clear that bp for the midcolumn or midrow of table 2 is one half, and that mean bp for all three columns or all three rows is one half. This latter case of mean bp for the whole table is the one usually calculated for regression of offspring on one parent. If a and A alleles are equally frequent, frequencies of the three columns are ex- pected in the ratio 1:2:1 and dominance effects on regression are effec- tively cancelled. Note that bp is always one half if k = 0. But if a alleles are in the minority, the frequency of the right column will be greater than that of the left column and expectation is that dominance will depress mean partial regression below one half. This seems to be an adequate explanation of low regressions of yields of corn hybrids on yield of inbred parents. No alternative explanations of higher order inter- actions of genes or of inefficient plot technic appear to be necessary. The function, F1 ~ blaPl + blbP2 + b2PlP2 + C may be fitted to data on samples of homozygous parents and the several Fp crosses, or F2 by selfing Fp. For Fp data, estimates of bn are estimates of (l+k+kT/na)/2, on the assumption of additive gene action. Estimates of fire estimates of -k/2nd. Regression of bp on Pp or on P2 is the same estimate of -k/2nd. As indicated last year, the general regression function may be solved to obtain estimates of bottom recessive, top dominant, and average degree of dominance. From the regression of bp on Pp, the estimate of Pp for bp = 0 may be obtained. This is the critical value of Ip. Such a tester combines equally well,with poor, medium and good lines on the average. Better testers may be expected to combine better with low lines than with high lines, bp is negative. The several estimates reported last year are in all respects surprisingly consistent with the hypothesis of overdominance in vigor of corn. Tests of significance of b2 reported last year are apparently in error. The appropriate test is for significance of departure from linear regression (Snedecor 14*3). By this test no single estimate of b2 is significantly different from zero which may mean merely that numbers are too small,. The crucial point for over dominance is 7/hether k is signifi- cantly greater than 1. An additional set of data from C, II. Woodworth, Oren Bolin and Earl R. Leng of the Illinois Experiment Station gives essentially the same picture. The critical value of Pp is 4»4 bu./A. Yields of inbred parents range from 2 to Mean yield of Fps is 103. We have then one more set of data consistent with the others in supporting the conclusion that the more vigorous inored lines in hand are worthless or worse as testers for general combining ability, since tp is zero or negative with such lines as testers,. That the few sets of data are not crucial for overdominance is not surprising. They would not be crucial even if the test for k greater than 1 showed high significance in each case. So few cases of monogenic inheritance and linkage would not prove the chromosome theory of heredity. When many more sets of data on different types of characters in both cross and self-fertilized species have been analyzed wo may have a clearer picture of where and to what extent dominance bias occurs. But even then 647 the results can hardly be conclusive and we will probably still need to be content with theories which agree best with the whole body of evidence. There is a suggestion in corn yield data that the relative order of rank within either a group of inbred lines or within a group of hybrids may be quite different in two different environments. Further, the shape of the fitted regression surface may also vary greatly in response to environmental effects. If alleles A* and A perform different functions in the sense of East, A*A’ may be usually inferior but sometimes superior to AA. The heterozygote A ’A if better buffered to environmental shifts may be on the average superior to either homozygote. In these events, A will probably be the more frequent and also the dominant favorable in the usual environment. But the possibility exists that in some environments A 1 will be the dominant favorable, with dominance still in the direction of greater vigor. The dominant favorable A ! will be in low frequency. The ratio k of an average dominance effect to an average basic effect may be changed and with it the equilibrium gene frequency ratio. All of these shifts will be likely to appear in the regression analyses for a given sample of stable lines and Fqs in different environments. Fred K. Hull Addendum. Since the above report was typed I have received from Dr. Faul H. Harvey yield records on 12 lines and the 66 Fqs and have now completed the first part of the analysis. Yields of lines (selfed four times) ranged from 12 to 24 bu./A. Mean Fq is 46. The critical value of P is 25, one bushel above the top line, These data seem to agree with the other sets and the conclusions drawn from them in all respects. These last results have given me .sufficient confidence to pro- pose a further attack for which a consideraole body of data is now avail- able, - data on Fqs but not on the parens lines, Mean F-j for any column of table 2 may be considered a measure of she general combining ability G of the constant parent for that column It '.s easily demonstrated that G is a linear’ function of P, Hence, we nay as well estimate the G value of a tester which provides zero partial \egression of Fi on G. Where the several Fqs of a group of lines have been tested in as many as four repli- cations, one half of the replications may be employed to estimate G values for the lines. The remaining replications may estiutcvr.Q Fqs» Correlation of experimental errors in the two estimates are thus eliminated. The analysis, as before, is to run the simple regression of each Ft column on the parallel column of G; then to run the simple regression of the first order regressions on G values of the respective constant parents; and finally to estimate G for bp = 0. If this critical value of G is within the range of the data the only direct interpretation I have found is over- Gominance. _nc. of analysis has been run With the Ctc»"to. Oil LcIt/0 If <312.07/ Sirvle Crosses from the cooperative tests of tne o k 3 1 o.iiOi 12 0.4 648 Agriculture with Ohio, Indiana, Illinois, Kansas, Nebraska and Oklahoma in x94-3. Mean G for each line was based on the data of five states for analysis with F^ data of the sixth state in each case. The critical value of G is below the G measure of the top line in three cases and slightly above in t?/o cases% In the sixth case the trend of regression is upward and^the data are apparently not consistent with any dominance bias toward high yield. Interstate correlations of G values of the ten lines are mostly positive but not very large* This kind of analysis is apparently of some worth where such data are available but it would seem that the attack outlined in the preceding paragraph would be more effi- cient and also applicable to more data* Fred H. Hull Harvard University Cambridge, Massachusetts 1* Midcob color described by Demerec some years ago is probably due to one of the alleles of the R series. At least the gene responsible for it shows close linkage with G on chromosome 10. Color in the cob is associated with colored internodes in the stalk. 2. In various strains of the Guarany corn of Paraguay mid—cob color is frequently associated with a faint purple color on the pistillate glumes or bracts. The gene responsible for this color is an allele of PI and shows linkage with Y on chromosome 6. In the presence of B the purple glume color becomes very intense and is also extended to the leaves and stalks* This new allele, or another in the series, seems also in certain stocks to be responsible for the basal glume in the tassel. 3. Most of our time and space this season was devoted to de- termining on v/hich chromosomes are located the multiple—factor segments which distinguish maize and teosinte. Relatively isogenic stocks, homo- zygous for one or more multiple-factor segments, were produced by crossing four varieties of teosinte with an inbred strain, backcrossing three times to the same inbred, and selfing. These were then crossed to a nine-gene linkage tester and backcrossed to a second niner-gene tester. The ears in these populations were then classified with respect to presence or absence of the multiple-factor segments from teosinte. Such classifications are far from completely accurate, because the effect of the segments vary with the influence of several genes in the tester stock, especially ± and g. Linkages can be detected, however, even when the classification is purely arbitrary, although exact crossing-over percentages cannot be determined from these particular studies. The results of these tests are shown in the accompanying table. Analysis of the data was greatly simplified by the use of McBee punched cards which can be sorted with a simple, inex- pensive tumbler. 649 Table I. Summary of linkage relations of the multiple-factor segments derived from four varieties of teosinte Total Variety Number number of of Linkage with chromosome number chromosomes teosinte segments 1 2 3 A 6 7 8 9 10 tested Florida i — — 4" — — _ r~ — — 1134 u 1 - - + - - - - - - 1530 i 1 - - - + - - - - - 1575 it 1 - - - + - - - - 1512 ti 2 - - - - - - + - 1512 it 2 - - -t + - - — — — 828 ! 2 _ — I + - — — — — 1386 I 2 + - - + - - - - - 675 Summary 12 + - 4" + - - — + — 10152 Durango 1+ I •f •T -» -T» 567 ii 1+ I - - 4- - - - I - 756 ii 2 + I — - — - - - 1305 it 3 - - - + - - - - 1494 Summary 7 + - + + - - - + — 4122 New 1 _ _ I , , I 1539 it 1+ I - — + - - - - - 855 it 2 I — — -t- — I - - 1575 it 2 - - - 4* - - - I - 1440 Summary 6 I - - + - I - I - 5409 Nobogame 1 , _, + — — 1359 ii 1 — — + - - - - - 765 n 2 _ _ _ + — — - I - 1521 it 2 - - + - - - - - 1602 Summary 6 - - + + - - - I - 5247 Grand Summary 31 + + 4* — I — + — 24930 + = Linkage I = Indication of linkage - = Independent inheritance 650 The important fact gained from this study is that the multiple- factor segments which distinguish maize and teosinte are located on chromosomes 1, 3? and 9 in Florida and Durango teosintes. In Nobogame teosinte which had previously been shown to carry only three major seg- ments, chromosomes 3> /+> and 9 are involved. In "New" teosinte chromo- somes 3) Ui 9» and possibly 7 are involved. The remaining chromosomes ap- pear to carry none of the major multiple-factor segments which distinguish maize and teosinte. They are probably not lacking in genes which effect the various characters which distinguish the two species but these are either modifiers or segments too small to be detected by the methods fol- lowed in this experiment which depend wholly upon dominant or partially dominant effects. It should be noted that chromosome 6 was not represented in the nine-gene linkage tester. Previous studies on crosses of Florida teosinte v/ith a stock including bm^ on this chromosome gave no indication that it is involved in the four major segments* The exact location of these segments and their length is yet to be determined. The segment on chromosome 1 3hows very weak linkage with bmp and since previous experiments with Florida teosinte had shown one of the segments to be strongly linked with P at the opposite end it is prob- able that this segment involves part of the short arm of chromosome 1. There is some crossing over within the segment. The segment on chromosome 3 shows 25-30 per cent of crossing over v/ith A. This segment is usually transmitted intact. Crossing over, if it occurs at all, is not readily detectable. The segment on chromosome A includes the Su locus. There is considerable crossing over (about 30 per cent) within the segment. Nothing is' known about the position of the segment on chromosome 9, or the amount of crossing over which occurs within it. The effects of the different segments are alike but not identi- cal. All reduce the size of the seeds, and the diameter of the ear. All of them increase the prominence of the glumes and the number of ears pro- duced on a single plant. At least tv/o of these segments contribute very noticeably toward the reduction of number of rows of grain. In another experiment single segments were first rendered heterozygous by crossing with the original inbred strain, and the hybrid was then crossed with a second inbred to produce a vigorous and uniform F^ in which approximately half of the plants were heterozygous for the segment. Ears from plants heterozygous for the segments average tv/o rows of grain less than those which lacked the segments. The segments have no discernible effect upon the pairing of spikelets or response to length of day. It is probable that they carry genes affecting these characteristics but that threshold limitations pre- vent single spikes from appearing at these levels. The corresponding segments derived from different varieties of teosinte are similar in the nature and magnitude of their effects. In each case the segment on chromcs.rm U is the most "potent." In each case this segment exhibits crossing over within the segment* Furthermore, 651 a stock derived from Florida teosinte and homozygous for the segment on chromosome 4 is almost identical with a corresponding stock derived from Nobogame teosinte. Differences in teosinte varieties are attributable to: (1) Differences in the number of major segments; (2) the genetic nature of the maize varieties into which they have become incorporated; and (3) the probable presence of additional smaller segments or modifying factors. We have some evidence that a single segment in heterozygous condition can increase yields appreciably, the extent to which this hap- pens depending in part at least upon the kind of germ plasm with which it is combined. Hybrids involving some inbred strains are noticeably im- proved when small amounts of teosinte germ plasm are included. It has so far been impossible to detect these segments cyto- logically. Stocks heterozygous for the segment on chromosome 4 occasion- ally exhibit a region of weak pairing on chromosome 4> but since similar regions are found on other chromosomes little significance can be at- tached to this. Apparently the segments are at least partly homologous to the corresponding regions of maize chromosomes so that there is no regular and distinct failure of pairing. The new data seem to establish beyond any reasonable doubt the hybrid nature of teosinte. At least the varieties so far studied are nothing more than maize which has been contaminated by another species. The contamination is not a random one but involves multiple-factor seg- ments of four, or in the case of Nobogame teosinte, three chromosomes. These foreign genes must have come either from Tripsacum, or from a "pure” variety of teosinte now extinct or yet to be discovered. F. C. Mangelsdorf (Ed. note: In correspondence Dr. Mangelsdorf has written, "I have an abundance of seeds of several nine-gene multiple testers and shall be glad to share it with anyone who wants some.") Kentucky Agricultural Experiment Station, Lexington, Kentucky and U. S. Department of Agriculture, Beltsville, Maryland, cooperating "Scattergrain" white double crosses. In the fall of 1945 a number of farmers’ fields of hybrid corn were reported in Kentucky, Tennessee and Indiana which failed to set seed properly. In several fields examined near Henderson, Kentucky, the seed set ranged from as low as about 20 per cent to 8$ per cent or better* The difficulty received considerable local publicity and the hybrids concerned were locally designated as "scattergrain" hybrids. The trouble was restricted to white hybrids but the reports indicated that hybrids from several different seed corn companies were involved. Evidence 652 pointed to male sterility on a field-wide scale as the cause of the poor seed set. The amount of sterility occurring in the same hybrid varied from field to field and seemed to be worse in bottom-land fields that were planted late. On the basis of information obtained on the pedigrees of some of the offending hybrids, seed of a series of reciprocal single crosses was collected or produced in the greenhouse during the winter of 1945-'4-6. Observational plantings of these singles and several of the "scattergrain" double crosses were made at Lexington, Berea and Henderson, Kentucky, and at Beltsville, Maryland, in 194-6. The data obtained do not permit a critical analysis of the cause of the sterility as, for some unexplained reason, the sterility occurred with a much lower frequency in the single crosses than in the double crosses. Sufficient data were obtained on the sterility, however, to suggest the following as important contributory factors: 1. The sterility seems to occur only in crosses which have a cytoplasmic contribution from 33-16, an old inbred line developed in Indiana. 2. Sterility in the hybrids also is influenced by contributions from the male parent. The substitution of only^one line in the male parentage of one of the ,fscattergrainH double crosses, completely eliminated the sterility in the re- sulting double cross, 3. The expression of the sterility is very subject to environ- mental influence. Merle T. Jenkins L. M. Josephson Missouri Botanical Garden, St, Louis, Missouri, and Pioneer Hi-Bred Corn Company, Johnston, Iowa Inflorescence structure and row number. ■ Two abnormalities have previously been described which affect row number in maize, each in its own particular way. (l) Multiplication, recently described by Cutler, produces two spikelets where normally there would be one. In its lowest expression it is responsible for the occa- sional kernel squeezed in between the regular rows of northern eight- and # ten-rowed flints. In its most extreme development it produces the crowded and apparently rowless ears commonly seen in parts of Central and South America. (2) Condensation (Anderson, Ann. Mo, Bot. Gard.)^is a telesco- ping of successive internodes and is most easily analyzed in the tassel. In its extreme form it produces an eliptical or flattened, more or less fasciated ear. In its less extreme expressions it is responsible for most row numbers of 16 or above. 653 While these phenomena are not unknown in other grasses, as has been demonstrated by Cutler, they are both of them of a more or t le er sa st ological nature and it seemed probable that a study of the in c fe ln oc re e ss -tructure in varieties of maize which have neither mu cl ot ni dp el ni sc aa tt ioi no n n om ri ght be illuminating. A special effort has been ma s dt eu d ty o such strains and, as anticipated, the structure of their inflore c se -nces (tassels and ears) is much simpler than in other kinds of P ca orr nt *i cularly as it concerns the central spike of the tassel, it do s ee se m n ot o have been previously described. It is not spiral but whorle T dh .ere are two extreme types, those with whorls of two and those wi whorls of three. Old-fashioned eight-rov/ed flint corns are an^example of one extreme. Their central spikes are in whorls of two pairs of spike e la ec th s ,w horl bearing its spikelets at right angles to the whorls i a mb mo ev de i ao tr e li ym mediately below. The uppermost tassel branches are_also l y c li en a rw horls of two. The other extreme type is found in certain p e en rt sl iy s 12- and H-rowed strains of corn from South America and the S w oe us tt h. - They have a structure similar to the eight-rowed flints b c ue tn tr ha el spike has whorls of three pairs of spikelets and the upper o f pot rh te iot na ssel has whorls of three branches. In the^Great Plains t v ha er ri ee t ai re es with from 10 to 14- rows. When they are without condensation t hey show various mixtures of two-whorled and three-whorled. The apparent spiraling of the central spike is due to the regular alternation of two patterns of spikelet position from no n do ed e. o In the eight-rowed flints, for instance, if the spikelets a t rh ee on no rth and south sides at one node they are on the east and west at t he next, then the north and south again, and so on. In the c o lr ^ns r ot wh ee re is a similar alternation from positions A,C, E, to positions B, p, F, and then back again to A, C, E, producing a six-ran S ki en ac e s Pea ^c eh * spikelet pair on the ear produces two kernels of corn the e e aq ru ivalent of a fourr-ranked spike will be an eight-rowed ear, for ranked spike it will be a 12-rowed ear. The structure of the tassel t h mes e eight-and 12~rowed races is almost transparently simp a ed . dition^of a little condensation or multiplication, however, prod a un c eo sr gan so difficult to analyze that until these less complicated h ad y pb ee en studied the basic whorling was pretty completely concealed. These observations allow us to put forward a series of hypoth- eses as to the various processes affecting row number in North A c mo er rn i. c anT ^h ey have already been tested genetically in part; further experi- ments are under way. The hypotheses are as follows. There are at least four quite different characters which affect row number in maize. Each operates a different lever s ( o1 ) t oM a si pz ee a ki .s fundamentally either in whorls of two branches or who t rh lr se e, o f or in various mixtures between these two extremes. There are d ii nc -a t .i ons that the genetic differences between the two-whorlea ana e three-whorled are multiple factoriu.L* In North America this basically simple difference is compli b cy a tt eh de almost universal presence of (2) Condensation. Freliminar r ye gs eu nl et s suggest that this may be a single recessive gene, with a number 654 of modifying factors which usually hold down the expression of this fundamentally teratological condition. In Central and South America (3) Multiplication is also an important factor in differences in row number. Nothing is yet known about its inheritance but various states of the phenomenon are known from very slight to very extreme. Except in an occasional inbred it is of little consequence north of Mexico. In addition to the above processes, row number can also be affected by the development or lack of development of the second floret as in Country Gentleman sweet corn and in various strains from South America. These hypotheses can all be tested by orthodox genetic methods as soon as there are available multiple marker stocks which exhibit extreme values for the above phenomena, viz., condensation vs. non- condensation, three-whorl vs. two-whorl, multiplication vs. no multipli- cation, Edgar Anderson Pioneer Laboratory, Pioneer Hi-Bred Corn Company Johnston, Iowa Among 80 dent corn inbreds of commercial importance, chromosome knob numbers range from 2 to 8 with a frequency distribution as follows; The nodal knob number is 4 with 3 and 5 as the two next most frequent classes. Knob number is strongly associated "with at least two 655 morphological characters - number of rows of kernels and devel h ou ps mk e ntl ea of f blades (flag leaves). As knob numbers decrease, d e rc or we a ns ue m ba en rd s flag leaves become more pronounced. It is assum k en do b t hn au tm b le or ws , low row numbers and long flag leaves were C io nr tn r oB de ul ct e dd e in nt t oc orn from Northern flint varieties. It is i p ne tr eh ra ep ss t is ni gg n ai nf di cant that these characters are so strongly l a if nt ke er d a t hc ae tn t eu vr ey n of breeding they still remain together in dent corn lnbreds* Although exceptions have been obse a rl vl e dc ,o r tr he el ra e is also an over- tion between high knob number and shape of ear. For example, those inbreds which approach Mexican Pyramidal in ear shape usually fall into the higher chromosome knob groups. William L. Brown Princeton University Princeton, New Jersey New alleles of 4, The alleles A*3 and aP, originating from Ecuador r e as np de c Pt ei rv ue ,l y, are'associated with brown, F-determined, pericarp ( E cm oe lr os ro n and Anderson, Genetics 17:503-509- 1932). Bo d to hm i an la ln et l et so aA r e( Nor _t h American origin), which is associated wi c ta hr p r ec do l po er r. i Several mutants having intermediate plant c a or li os ri n eg f fs ep co tn st a an ne do usly from Ab have a brown pericarp effect which likewise is dominant to the red of A (Stadler, News Letter 17i20-21. d i 1v 9e 4-r 3g )e nt ia hc et ion of the A alleles of North and South Ameri r ce av ne a ol re id g if nu r it sh er in a series of dosage and dominance studies th ce o na du ut ch to er d b( yM icrofilm Abstracts 7: No. l) and is being inves t the ir g atu es di ng f ure -xotic material collected from isolated region k si n od fl y P es ru up p al ni de d by the Pioneer Hi-Bred Corn Company, Johnston, Iowa. re Ss omu el ts of the preliminary work are reported here. 1. Dominance effects of Peruvian alleles associated with ful p lu rple-aleurone color (A-P). Small progenies from individ p uo al ll ,i n °a Ite ^d _, Feruvian ears were planted at Columbia, Mi a sn sd o urc ir ,o ss mes 1w 94e -r 5e made on aa and on A^> The progenies of w ti ht eh ^t h co rs oe s sF ee sr uvian plants which were shown to be homo d ze yt ge or um si n .i on rg af lu ll el l- ep su rple aleurone color were planted at Ames, I S oi wan ,c e it nh e 1 9A 4 - • plants in the 1945 crosses were either An o f o rp r Ao ag ,e n ti we os kw ie nr de s expected* designating the A-F aliele i sn d ci av ri rd iu ea dl F >e r -u nv yi an plant as A-Pp and A-?2 these progenies were expected to contain plants of the following genetic constitutions: Cross (1945) Types in progeny A/A x A-P p/A-Pp Ai-Pli A/iirp2 A/a x —A- P,1 '/ —A-P, A i - W J a/4~p2 » a /4- Both types of progeny afford a test of the dominance effects of the 656 Peruvian alleles, the; first in compounds with the A allele and the second in heterozygotes with both the A and _a alleles* Crosses were made on individual plants within progenies using _aa Dt Dt plants as a pollen source. Progeny type was thus distinguished by the presence or absence of dots and this was also the basis for distinguishing A/A-P from a/A-P plants within progenies of the second type. Seven such progenies repre- senting the test of A-P alleles of separate origins in Peru were classi- fied for pericarp color; the available data are summarized in the follow- ing tables. k/k - I Family Cross red br own 117 A/A x A-F/A-P A 7 119 Same 9 H 120 Same 20 0 k/k - P kJk - P Family Cross red brown red brown 118 A/a x A-P/A-P 3 A 2 3 122 Same A 5 Ao- 1 123 Same 0 3 0 3 12A Same 5 0 2 0 In spite of the small numbers involved in these progenies it is obvious that the A-P alleles of isolated origin are not similar in their effects on pericarp color. Moreover, in the cases of four of the seven progenies (all excepting families 120, 123; and 12A) the two A.-P alleles associated in individual Peruvian plants show contrasted behavior. The data suggest that A-P alleles, so far as these progenies represent them, are of two types: One determining red pericarp color and indistinguish- able from A; the other determining brown pericarp color and having an effect completely dominant to that of A. There is no evidence for the existence of an A-P allele having a brown pericarp effect which is re- cessive to A, unless it be found that the progenies of the red pericarp types in families 117, 119 and 120 segregate ears showing brown pericarp color. 2. Dominance effects and response to Dt among Ieruvian mutants of the aP and a type. Some of the Peruvian plants which were crossed to A tester in 19A5 'were not homozygous A-P; six of the test cross ears gave 50:50 ratios for purple; colorless aleurone and two gave 50:50 ratios for purple; pale aleurone. In -each of these eight cases some of the seeds having colorless or pale aleurone showed dots. Since the tester parent was a,dt adt rr GO DtDt in constitution, the presence of these dots establishes with certainty that the colorless and pale seeds are due to mutant alleles at the A locus; if a dominant dilution factor or a reces- ■ sive factor other than a, wore responsible for the dilution effects the 657 seeds would be expected to be without dots. This apparently is the first report of the occurrence of recessive a in South American material; since five of the six Peruvian plants which were found to be heterozygous for _a were of separate origin this mutant probably is widely distributed in Peruvian material. It is likely that these types failed to be recognized earlier because of the frequent occurrence in Peruvian material of the recessive forms of the genes R and C, which complement A in pigment pro- duction and because they may not have been studied in backgrounds provid- ing the Dt gene which is specific for a, The action of the pale mutants (designated sP-T) was studied further in progenies providing the combinations aP- P~/a and aP-P/A, In the cases of both pale mutants, the combinations with recessive a were invariably associated with brown pericarp color, as were those with A. To test the response of the aP-F alleles^to the Dt gene* crosses were made between aP-P/a and the tester a ^ Dt Dt (the a_a ̂gene does not mutate under influence of Dt). Without exception, the pale seeds (a.P-p/a^l, Dt) on ears from these crosses were without dots, whereas colorless seeds > £t) on the same ear were dotted. Hence, both aP-P alleles are similar to _aP in their pericarp color effects and re- sponse to Dt, though they may differ from each other and from aP in the matter of their determination of plant and aleurone pigmentation. Similar studies are in progress with the six I eruvian _a mutants (designated &r*F) • The limited data which are available at the time point to a divergence in type of action within the a.—P group as well as between members of that group and recessive _a. All six members are associated with brown pericarp color as determined in heterozygotes with a.. Dominance effects in compounds with A have been determined for only two of the six mutants but in both causes there is complete dominance over the red effect of A. This is the first knowledge of an _a allele which is associated with colorless aleurone and brown plant color, in which respects it is reces- sive to A, and yet shows complete dominance to A in its effect on peri- carp color. Of the four _a-P mutants tested for response to the Dt gene, one proved to be dottable, the other three being without response. The two mutants mentioned as showing dominance to A in pericarp color effect do not respond to Dt. Except for the products of X-ray and ultraviolet treatment there are no past reports of _a mutants which fail to respond to Dt; Rhoades (News Letter 15: 6. 19A1) describes an a mutant which is in- distinguishable from _a with the exception that it shows much reduced re- sponse to Dt, but this allele, unlike the a~P alleles, is recessive to A in pericarp color effect. The lack of response to Dt reported here for three naturally occurring ja—F mutants suggests that the failure to dot in the presence of Dt is not a valid criterion of deficiency at the A locus. The evidence reviewed here adds to an already complex picture of gene action at this locus. Most significant, from this standpoint, is the evidence on the extreme antimorphism of at least two of the ti-P alleles. The antimorphic effects of certain of the A alleles have been reviewed previously (Microfilm Abstracts 7: No. 1). The evidence is not in support of certain hypotheses, notably those of Wright and Stern, which have been advanced to explain antimorphic effects. It is suggested that the antimorphic behavior of the alleles of A may be explained on the basis of an hypothesis which holds a single gene capable of entering into 658 tv:o different reactions. It is the purpose of further investigation of the Peruvian alleles reported on above to provide additional tests of this hypothesis. J. R. Laughnan Texas Agricultural Experiment Station College Station, Texas For a few year's observations have indicated that teosinte has more tolerance to heat and drought and possibly more resistance to cer- tain diseases and insect damage than corn. Efforts to improve inbred lines of corn by modifying them with teosinte characters have progressed far enough to give a suggestion of the results to be expected. Various Texas lines were crossed with Florida teosinte, backcrossed to corn from once to three times, and selfed each generation afterwards. In the de- velopment of the modified lines, no effort was made to select by observa- tion among the segregates available for use. Plants were selfed at ran- dom, and only those plants or ears that were seriously affected with such abnormalities as disease, insect damage, and sterility were later dis- carded. Tests of the desirability of the modified lines as compared to the original (unmodified) corn lines were of two kinds: (l) Tests of the lines themselves to compare their tolerance to artificially applied heat; (2) Yield tests of the various lines crossed to a common tester, conducted under field conditions, 1, heat-tolerance tests. The procedures followed in making tests for tolerance to heat were based on those used for several years at the Kansas Agricultural Experiment Station, although in some respects there are considerable differences between the Kansas methods and mine. Inbred plants of Tx4R-3 ana of eight modifications of it were grown and given artificial heat treatments in an oven in six replications, each replication being grown ana treated at a different time. Glazed pots with top inside measurement of four inches were used, The pots were selected for uniformity. The soil used for the first five replications was a thorough mixture of sandy loam and compost. That used fox* the sixth was relatively homogeneous Houston Black Clay. In each replication, five pots of each line were planted, and an effort was made to have a final stand of two plants to the pot. This procedure usually resulted in 10 plants of each line for each replication. The plants were given the artificial heat treatment when 13 to 15 days old. The oven used was electric, automatically controlled, with forced ventilation. It was designed for other purposes, and the fluctua- tion in the temperatures obtained led to some difficulties. However, after a few replications had been treated for practice, the method was found to be usable. Prior to each application of heat, the soil in the pots was 659 well-saturated with water. The pots were randomized in the oven and kept under heat treatment for eight hours at 55° C. After the treatment was complete, the plants were kept in the greenhouse for 5 to 30 days without water while the readings of the results were taken. It was found most practicable to take the first reading about 24 hours after treatment, because the extent of the damage to the plants was more readily determined after this lapse of time. The best method found of recording the results was to tabulate the number of days that each plant lived after treatment. In most of the replications no plants were living 10 days after treatment, and those which did live this long or longer were considered not to have been killed by the treatment. For the purpose of analyzing and studying the results, it was found desirable to assemble all the data for each entry into a single score. In order to accomplish this objective, the combined number of days that all the plants of an entry lived after treatment was adopted as the score. Thus, in the fifth replication of modified line No. 1, the 10 plants lived the following numbers of days: 3? 6, 3> 20, 3, 17, 3» 3> 5, 15. But,since a plant is not considered to have been killed by the heat treatment when it lived 10 days or longer, all numbers above 10 were reduced to 10, and therefore the numbers actually added in order to get the score of this entry xiere 3> 6, 3? 10, 3? 10, 3, 3, 5» &hd 10. The score of this entry, therefore, is 56. The highest possible score is 100, and the lowest is zero. The score of each entry is shown in table I, the various lines being listed in descending order of their observed tolerance to heat: Table I. Replications Lines 1 2 _3 _4 _6 Average 3 4-5 33 20 85 100 62 58.3 9 32 26 30 100 96 60 57.3 5 4.7 22 12 90 96 30 49.5 6 28 22 16 71 100 59 49.3 4- 26 22 16 60 94- 61 46,5 Tx4R-3 36 13 10 50 87 42 40.5 1 22 32 26 77 56 26 3 9 .8 2 18 14. 20 30 93 33 34.7 7 36 14- 16 34 69 30 33.2 For significance, .05 - 14*6 Since the difference necessary for significance^on the .05 level is 14..6, the indication is that two of the lines modified with 660 teosinte characters are more tolerant to heat than the original line Tx4R~3. Whether tolerance to heat and to drought are related phenomena, as reported by some investigators, has not been determined in this study. However, the yield tests, to be discussed in the following paragraphs, were conducted with that possibility in mind. 2. Yield tests. One yield test was conducted each year from 19̂ .3 to 1945 on hybrids involving the group of Tx4R-3 lines tested for heat tolerance, and several tests were conducteo. on certain other groups. In all the yield tests, the uniform tester was a single cross, commonly i one with which the original inbred is combined when put into agricultural use. One or more checks were always included. Except where the contrary is indicated, one check was the original inbred crossed with the uniiorm tester, and various hybrids whose usual performance was known were often used as supplements. The most satisfactory results of yield tests were obtained with groups of lines other than Tx4R-3 and its modifications. Although results of' the heat tests indicate that additional tolerance has been introduced into Tx4R-3 by crossing it with teosinte, no field test has shown convinc- ingly that the yielding ability of any of the modifiea TxAR~3 mines shoula be adjudged superior to that of the original. Tests conducted ouring 194o and 1946 showed only that some of the modified lines were in the same class with the original Tx4B-3 and that others were inferior. As would be expected, one or more modified lines gave actual yields greater than the original Tx4R-3 in each test conducted, but in none of these instances was the difference significant. It should be pointea out, however, that tolerance to drought did not have a fair chance to manifest itself in terms of yield in any test conducted on the Tx4E-*3 group# In 1943 and 1914 the yield tests were a failure, principally because of poor stands and accidental damage. In 194$ end 1946 there was no appreciable drought during the critical part of the season. More interesting results of yield tests were obtained with a group of modified Txl27C lines. A small portion of the results of the two tests conducted in 194$ and 1946 is shown in table II. The 194$ test of the Txl27C lines contained 36 entries and the 1946 test contained 25 entries. Since the two tests did not contain the same entries, but had only certain ones in common, it is impracticable here to combine all the results briefly in one table. However, the fol- lowing table does Include the highest-yielding entry and one check in each test. ; The lowest-yielding entry tabulated here from the 194$ test stooa 14th among the 36 in the test, and the lowest shown from the 1946 fest stood loth among the 2$ in the test. A blank indicates the omission of the entry from the test. 661 Table II, Average yield bu. per acre Pedigree* 1945 1946 4.2116-21-2 44.8 59.5 4.2116-25-3 4 2 .6 Tx, Hybrid No* 18 (Ck.) 4 0 .8 4.2116-15-2 39.4 65.7 4.2116-27-1 3 8 .2 49.3 42116-28-5 37.0 55.4 42116-28-4 45.6 Txl27C (Ck.) 44.0 Difference for significance, .05 7 .2 6 9.75 Difference for significance, .01 9.63 12 .06 *The tester in each instance was Txl73D x Tx203 It may be observed frorrfthese results that some of the Txl27C modified lines, such as 4-2116-21-2 and 42116-15-2 , show considerable promise. It is interesting that some of them gave improved yields during a season v/hen there was no serious drought or other hazard to which teosinte is known to be especially tolerant. Of course there are possi- ble explanations. It seems fairly probable that the introduction of teosinte germ plasm into Txl27C resulted in modified lines with more re~ mote relationship to the tester. Remoteness of relationship between the two parents of a cross is often believed to be an important factor af- fecting hybrid vigor. Another possible explanation is simply that addi- tional "yield genes" have been acquired from teosinte. A few teosinte-modified lines of Txl32A and Txl02A have been developed and tested, but the results to the present do not indicate appreciable improvement in them. R. G. Reeves 662 United States Department of Agriculture Plant Industry Station, Beltsville, Maryland A pair of genes influencing the intensity of yellow endosperm color was reported in the Maize News Letter for January 31> 194-4. Segre- gations of 3 dark yellow to 1 lemon yellow v/ere obtained in selfed prog- enies. The gene in question wGs closely linked with opaque-2 in chromo- some 7. No symbol was suggested. The situation with regard to the genes for endosperm color is not entirely clear. Five genes have been numbered and one or two additional genes apparently are known. It is suggested that the pair of genes discussed here be designated as Yg yg. Dur-ing the past season data were obtained on a three-point backcross test involving the cross _1--1--- 4__ . These data are reported -92 28 25 below: Parental R e c ombi nat i o ns combinations Region 1 Region 2 Region 1 & 2 404 374 6 11 21 23 0 0 778 17 44 0 2 .0% 5.2$ 0.0 The gene order indicated is c>2 - 2.0$ - yg - 5.2$ - v«j. Merle T. Jenkins United States Department of Agriculture and Cornell University, Ithaca, New York Natural teosinte-corn hybrids in Guatemala. Teosinte occurs as a weed in corn fields over extended areas in the Jutiapa - Progresso - Lake Retana area in south central Guatemala and in the San Antonio Huixta area in the northwestern part of the country. Botanists who have visited these areas, including Weatherwax, Kempton and Popenoe, noted the absence of hybrids in the fields where corn and teosinte were growing together and flowering at the same time. This was surprising in view of the fact that the two species were known to hybridize readily under controlled conditions and their hybrids are fully fertile. The Jutiapa r Progresso - Lake Retana area was visited in 663 November, 194.6, with Dr. I. E. Melhus, Director of the iowa-Guatemala Tropical Research Center, A thorough search for natural hybrids was made in corn fields containing teosinte as a weed extending for AO kilometers along the highways in this area. No hybrids were discovered. Extensive collections of corn and teosinte seed were made from these fields ana it is planned to grow this seed to determine whether natural crossing oc- curred during the current season in fields observed to have corn and teo- sinte of the same stage of maturity growing in juxtaposition. Subsequently, the San Antonio Huixta region was visited together with Dr. George Semenuik. As a result of an extended search in this area approximately 30 hybrid plants were discovered. With very few exceptions all of these plants apparently were first generation hybrids having typical four-rowed ears. One hybrid plant with eight-rowed ears and one with pre- dominantly two-rowed ears similar to the teosinte parent were found. Open- pollinated seed from these plants was harvested for a study of the progeny. An unsuccessful attempt to hybridize Guatemalan Tripsacum and corn. Having been successful in obtaining hybrids between diploid and tetraploid forms of corn and Tripsacum dactyloides native in the United States, the possibility of obtaining similar hybrids involving corn and Tripsacum species which are native in Central America was investigated. Tripsacum dactyloides is not known to occur in Latin America. Of the various species which do occur there, all that have been studied have proved to be tetraploids with approximately 72 chromosomes. Since very special conditions are required to obtain hybrids of diploid Tripsacum dactyloides and diploid corn, the possibility seemed very remote that the tetraploid Tripsacum of Central America would hybrid- ize with the diploid corns of that region. However, in developing an hy- pothesis of the origin of modern varieties of cultivated corn based on the assumption that teosinte resulted from the hybridization of Tripsacum and corn and that the chromosome knobs and various other important characters of corn came from Tripsacum by way of teosinte, Riangelsdorf and Reeves assumed that natural hybridization of Tripsacum and corn did occur in Central America. Hypotheses are of little value unless they can be tested. Fortunately, a direct test of this hypothesis, formulated nearly 10 years ago, involved no special difficulties. Tripsacum and corn were found to be in flower at the same time in readily accessible areas in the neighbor- hood of Guatemala City and Antigua at altitudes of approximately 5>000 feet. Lore than 200 ear shoots of native corn plants from three different fields were carefully pollinated with Tripsacum pollen from plants col- lected in their natural habitat in the same region. In making pollinations by applying a mixture of Tripsacum and corn pollen directly to the bases of the corn silks and in culturing the embryos of resulting aborted seeds, the same technique was used that previously had been successful at Ithaca in obtaining a considerable number of Tripsacum—corn hybrids. From three to four weeks after pollination each ear was carefully scrutinized for possible hybrid seed, the embryos of seeds suspected of being hybrid were cultured in a sterile nutrient agar and flown directly to Ithaca where their chromosome number was determined from root-tip counts. There were no hybrid seedlings. All had 20 chromosomes. 664 This test failed to confirm the assumption of'Mangelsdorf and Reeves that in the recent past Tripsacum and corn hybrids occurred in western Guatemala, subsequently designated by Mangelsdorf and Cameron as the secondary center of origin of cultivated maize. However, it would be desirable to make additional tests employing other species of Tripsacum which are found elsewhere in Central America, Also, a careful search should be made for diploid Tripsacums throughout Central America. L. F. Randolph University of Minnesota University Farm, St. Faul, Minnesota Linkage data on several unlinked characters were gathered and analyzed by graduate students. 1. The silky which appeared in the F2 of a cross between two inbred lines segregated in an F2 to give a ratio of 1$ normal : 1 si and approximately 3 :1 in a backcross. Red collar (base of tassel glumes) vs. green segregated 9:7 in Fo in one of these cultures. Based on small numbers, si was independent of red collar, sr, and ms (this ms was supposed to be as but did not show linkage with sr, also the ears were normal). Red collar was also inde- pendent of this same ms and sr. This silky shows no linkage with msp. Backcross tests indicated no linkage between PI and red collar, a result differing from that reported previously (News Letter 18:16-17. 19AA - PI vs, red collar = 6 ,6 per cent recombination). This difference is explainable if red collar is due to complementary factors. Antonio Marino I. Z. Hasanain 2. Woodworth's vp gives no evidence of linkage with msi. To determine the order of Y, pb, and ms; all very closely linked, Y + ms/y pb+ plants were crossed with y pb ms/+. One y + ms and one y pb ms were obtained, suggesting that this is tEe order of the three genes. H. A. McLennan F, K. White 3, One stock from X-ray treatment has 10 chromosome pairs and about 20 per cent of pollen abortion. The sterility shows linkage with factors in chromosome 2: 4-3,5% with glp, 34-*6% wTith 13, and 15,5% with V/(. 665 Preliminary cytological examination reveals bridges with fragments, in- dicating an inversion is the probable cause of the sterility, and that the centromere is outside the inversion. The ears show normal fertility. W. A. Russell 4. A survey of the knob numbers (and where possible the positions) in 20 inbred lines used in the breeding program here is being made to determine possible relationships with plant characters and with combining ability. The knob number varies from t?/o to at least eight, M. V. Vachhani The dominant white cap (Wc) endosperm factor is linked with brittle stalk (bk?) in chromosome 9 » the backcross numbers being 13$ Wc + , 67 Wc bk, 6$ wc +, 143 wc bk, or 32.2 per cent recombination. With T 8-9a there was 30mper cent recombination (Wc - T 8-9a - 18:33*68:2$), Since tests reported previously indicated no linkage with waxy (News Letter 18: 16. 1944) the order appears to be wx - bk^ — Wc; or wx - T 8-9& — Wc# A brown midrib character which appeared in a sh wx gl-̂ Q culture seems to be genetically different from the other three brown midribs, and therefore is bm,. — Is, Vivip£irous (vp^) is the same as Woodworth’s vp as shown by in- tercrosses. Tests areTn progress to determine the linkage group to which vp5 belongs. This will also locate one of the factors for yellow endo- sperm (unless v£r itself causes the color effect). Progress in building large rings (See News Letter 20:16. 1946). The different rings of six chromosomes produced as the first step in the program ?/ere backcrossed to normals; the progeny were grown and examined for pollen sterility. In each case, plants approximately 7$ per cent sterile were identified. These should be carrying the cross- over which combines the tv/o parental translocations in one gamete. Simi- larly, backerosses of the © 10 from l-$-6-7 ® 8 x ® 4 were grovm. It is hoped that the selected ears represent the desired crossovers, but the sterility classes were more difficult to distinguish by the ’’pocket microscope” method used in the field. Chromosome dis.junction (See News Letter 19:31* 194$)• In plants heterozygous for T $-6c, the low percentage of cross- ing over with the chromosome $ inversion in the translocated chromosome as compared with the amount observed with the inversion in the normal chromosome can now be explained without resorting to ’position effect”. When Dr. A. H. Sturtevant saw the data, he suggested that the cytological data on crossing over (percentage frequency of the crossover type or ’’half disjunction” quartet) did not measure crossing over within the inversion in both cases. When we drew the chromosomal diagrams (checked later) they 666 showed that this was true. When the inversion is in the translocated chromosome, crossovers within the inversion do not give rise to the cyto- logically recognizable ’’half-disjunction” quartets; whereas when the in- version is in the normal chromosome these crossovers are recognizable in that manner. In the one case these quartets result only from crossing over betv/een the translocation break (center of the cross) and the new position of the centromere, consequently comparable to that in the stock heterozygous T 5-6c but homozygous for the inversion. C. R, Burnham Linkage data calculation (See News Letter 20:18, 194-6), Fisher (Amer, Nat, SO:$68-578. 194-6) has presented a simple method of scoring linkage data by using maximum likelihood formulas. To make it readily understood, we have illustrated its application to F2 and F^ data commonly encountered in plant material (nov* ready to be sub- mitted for publication). The formulas*, for the scores (remainders) of maximum likelihood formulae when p = one half is substituted (50 per cent recombination), are: Information (i) per Formulas for scores F2 plant or line Source of data (c) at p - one half * at p = one half Backcross 2 (a - b - c t d) U F2 i(rbr * a> 16/9 F3 from Ab F2 plants 4-/3 (k - 2 j) 32/9 F-̂ from aB F2 plants A/3 ( i - 2 1 ) 32/9 F^ from AB F^ plants 4/9 (8e - f - g - h - i ) 128/81 F^ from doubly hetero- 4- (h - i) 16 zygous F2 plants * Suitable for repulsion, change signs for coupling. By substituting the observed values for a, b, c, d, e, etc., the score (c) for each source of data is obtained. The total amount of information furnished by the data is ni, where n is the number of plants or of Fo lines and jL is the information per plant or line, Fisher shows that "c2/l is distributed as X • Each such c2/l value for each source of data, having one degree of freedom, tests the significance of the deviation from 50 per cent recombination. Then ̂ - (ScJ^/SI tests the deviation from 50 per cent^fgr the pogled data with one degree of freedom. The difference “ sfef? - tests t i] SI 667 heterogeneity, the degrees of freedom being (N—1) where N is the number of sources of data pooled* For this test a value of £ sufficiently close to the best estimate of p should be used. The ratio Sc/SI provides an estimate of the correction to be applied to p * 0.5 to obtain the p value which best fits all the sources of data. H. H. Kramer C . R • Burnham Study and use of trisomics. 1 . The frequency of transmission of trisomics without root-tip chromosome counts can be determined by crossing each trisomic with a homo- zygous translocation involving that chromosome. The trisomic Fn plants will show low pollen sterility (25-30 per cent) as compared with the 50 per cent shown by their diploid sibs. With experience the difference can be recognized easily even in the field with the ’’pocket microscope”. I have used it satisfactorily for chromosome 6 , using T 5-6a. 2. It would also be desirable to make the trisomic analysis usable by those not able to get chromosome numbers counted. At present only plants trisomic for chromosomes 5 and 7 are phenotypically dieting guish&ble in most crosses, but not in all. Two tertiary trisomic stocks for each crhomosome might be estab- lished so that between them the entire chromosome in question would be represented in trisomic condition. If the piece of the attached non-homo— logue which is also trisomic came from chromosome 5 or 7, it might serve to identify the desired tertiary trisomic plants. Since these tertiaries would also differ from primary trisomics by having approximately 15 per cent of pollen abortion while the primaries would be normal, pollen exami- nation could be used as a supplementary check if desired or if the pheno- types were not distinct. In place of the 10 primary trisomics, 20 tertiary types would be used for a complete test of the 10 chromosome or linkage groups. For example, the series might be established from 2n + 1 (No. 1 chromosome trisomic) x T 1-5; 2n*+ 1 (No. 2 chromosome trisomic) x^T 2-5, etc., selecting the translocation in each case in which the break in 5 was near the middle of the chromosome, assuming a plant trisomic for nearly^ half of 5 would be most likely to be phenotypically distinct. Two terti- aries would be established for each cross. A series with chromosome 7 also might be usable. C. R. Burnham Chromosome disjunction. In discussing with many others the problem of getting lower sterility from large rings, the possibilities of genic control were sug- gested. On this basis, a planned search for factors affecting chromosome 668 behavior at meiosis, such as changed chiasma frequency or position, may be needed. Those studying inbred lines for knob number night be on the lookout for such effects at diakinesis and metaphase. Such stocks would be of interest for other problems also. Since such factors are likely to be recessives, it will be necessary to study selfed lines from X-ray treatment rather than the immediate plants obtained from the use of X-rayed pollen. I wish to acknowledge the assistance of H. A, McKennan, F, H. White, and K. Hanson. C. R. 3urnham University of North Carolina Raleigh, North Carolina Effects of the major plant color genes upon kernel weight in maize. Brink (1934) has demonstrated that maize plants belonging to the anthocyanin series of color types differ significantly in their aver- age production of grain. Comparison of the four anthocyanin types led to the conclusion that purple was much inferior to dilute sun red, while di- lute purple and sun red exceeded dilute sun red in average yield per plant. Subsequent unpublished results indicate that there is probably no signifi- cant yield difference between sun red and dilute sun red. Two trials in successive seasons in which dilute sun red (A b,£l) and triple recessive green (a b pi) were compared, suggest that dilute sun red has a signifi- cantly greater yield. In 1938 and 1939 the v/riter conducted three additional- experi- ments at Madison, Wisconsin, in an effort to clarify the status of those color types which had given inconsistent results and in order to include the brown class (a B PI) which had not occurred in earlier trials. A number of ears resulting from the backcross  a.p Bb Plpl x bb plpl were obtained. Two experiments, the first including 12 backcross families in three randomized replications and the second, with 18 families in two replications, were grown in 1938, A third experiment (12 families, 3 replications) was grown in 1939. The heterozygous A JB PI plants used in backcrossing were not closely related to the _& b_ £l stock and the segre- gating progenies exhibited considerable hybrid vigor. Five-eighths of the residual heredity in each family was derived from commercial strains of yellow dent corn adapted to Southern Wisconsin conditions. The plants were classified as to color type and distinctively tagged. No attempt was made to distinguish the a B pi and a. b £1 plants from jo b_ pi in the green class. The frequencies of each type within each row were determined; the mature ears from each color group in a row were harvested together. The samples were dried to a uniform moisture content, shelled, and the shelled corn weighed to the nearest ounce. The mean shelled grain Y/eights per plant for each plant color class in experiments I and III appear in table I. 669 Mean grain weights per plant by color classes Experiment I (1938) Experiment III (1939) Phenotype No. plants Mean in lbs. No. plants Mean in lbs. A B FI (purple )## 674 .307(6) 600 .282(6 ) A b PI (dilute purple) 681 .361(3) 6A1 .323(2) A B pl (sun red) 694 .355(4) 636 .318(4) A b pi (dilute sun red) 68S .372(1) 682 .331(1) a B PI (brown)*# 69S .344(5) 602 •305(5) a 3 pl, a. b PI, a b pl (green) 2002 .363(2) 2000 .319(3) Total 5 A3 7 3211 ## Highly significant differences between this and other classes. The analysis of variance for each of these experiments reveals that the low yield of purple is highly significant in both cases and that brown With a significantly greater yield than purple is significantly be— low the yields of the remaining four classes. The relative standings of the six color types with respect to mean grain weight are indicated by the numbers in parenthesis in table I. Dilute sun red has the largest mean in each experiment, the value being significantly (P » .01) greater than the pooled mean of the green, dilute purple and sun red classes in each case. In a combined analysis of experiments I and III the difference between dilute sun red and sun red is highly significant. The results from experiment II are consistent with the other two experiments with respect to the purple and brown classes. The differ- ences are again highly significant. The mean of sun red is second highest in the experiment instead of fourth as in I and III. This high value for sun red in experiment II is subject to question, however, for alien the analysis is based upon kernels per ear instead of kernels per plant, sun red is fourth highest while the relative standings of the other are but slightly changed. In this experiment, also, sun red contributes dispro- portionately to the variance. The error term is larger than in the other experiments making it impossible to pool the results of experiment II with the others. A summary of experiment II and the total frequencies of g&chiwcolcr type are presented in table II. 670 Mean grain weights per plant by color classes Experiment II (1938) Total plants Phenotype No. plants Mean in lbs. I + II + III A B PI (purple)## 806 .320(6 ) 2080 A b PI (dilute purple) 803 .370(3) 2125 A B pi (sun red) 88A .376(2) 2264- A b pi (dilute sun red) 920 .379(1) 2290 a B PI (brown)*# 84.8 .3-45(5) 214.8 a B pi, a b PI, a b pi (green) 2555 .367(-4) 6558 Total 6816 17.-465 ** Highly significant differences between this and other classes. A chi-square test for the correspondence of the observed fre- quencies of plants in each color class to the expected 1 ?1 .1 *1 :1 :3 back- cross ratio reveals that the frequencies shown in table II have a prob- ability of ,01. The largest deviations occur in the purple class which is smaller than expected and the dilute sun red class which is larger than expected. Since these are the classes which have the lowest and highest mean grain weights, respectively, it appears that the same genotypes which influence kernel weights also influence viability. Relatively large nega- tive deviations also occur in dilute purple and brown, while the sun red frequency exceeds the expected. It seems probable that the dominant gene, PI, has an adverse effect upon viability,. Plants with the purple phenotype carry the three dominant genes A B PI and are much less productive than those plants i:. which one or more of these dominant factors is not present. The brown plants which have the genes B and PI are at a similar but less marked disadvantage, The domi- nant genes were always present in heterozygous condition, Since the pres- ence of a single gene A is the only known condition which differentiates the purple from the brown type within a given family, it appears likely that this gene acting in conjunction with _B and PI results in a decreased storage of starch in the kernels. In contrast it is found that dilute purple, dilute sun red, sun red, and green, all have higher mean grain weights than brown. In the three anthocyanin color classes A is present, but b, pi, or b pi are homozygous. The heterogeneous green class includes combinations of a. with h, jpl or both in homozygous condition-. Therefore, it may be concluded that the _B PjL gene interaction is effective in reducing the mean weight of grain per plant, presumably by affecting starch storage 671 during development. The gene, A for anthocyanin pigment, in combination with PI increases the effect. The relatively higher yield of dilute sun red in all three ex- periments is noteworthy because this is the genotype which is virtually universal among North American varieties of dent corn. While the evidence is hardly adequate to demonstrate that this genotype is always superior in grain yielding potentiality, the fact that A b pi yields are probably significantly greater than those of A B pi is suggestive. In sun red as in purple and brown the development of deeply pigmented tissues must im- mobilize considerable quantities of carbohydrate which might otherwise be stored in the seeds. The possibility that the results reported are actually caused by other genes, rather closely linked to the three segregating color genes cannot be entirely rejected on the experimental evidence now available. The foregoing conclusions are abased upon a rather homogeneous sample of residual heredity tested in a single locality. Until further evidence is available on the point, however, it v/ould be inadvisable to introduce B and PI as markers in dilute sun red commercial breeding stocks. Ben W. Smith University of S, Paulo "Luiz de Queiroz” School of Agriculture Pi*caci.aba, S. Paulo. Brazil 1. Breeding program. Brazil may not yet be ready for large-scale irur oduonion of hybrid corn and premature widespread use might lead to a icsc if valuable genetical and breeding material in the numerous local populations. In view of these considerations.> I have tried since 1937 the following pro- gram of establishing homogeneous self-propagating populations. (a) Selection of the initial material, which maj e:t.uer consist of plants of local populations or nybrids combining doeired cbai asters. (b) Selfing during three to f our gen-ra oior.s and «1 irrigation of all pedigree lines which contain undersirable characters- (c) Sib and between-line crosses during about throe generations; selecting the most vigorous combinations, el marine Vug any bVacic, showing undesirable characters: and maintaining all 'ami. lias rev ora tea y (pedigree). (d) Thus, the final stage is reached afrer about seven to eight generations and all the selected families are united into one population which is maintained by open pollination end simple mass- selection for stock seeds. 672 Final results have been obtained by this method in establishing new sweet corn varieties: Piracicaba white P678, P18, orange P9» etc. Satisfactory, though only preliminary results have been obtained also with hard orange flint (cateto) and with yellow dent. After having essentially solved the question of producing sweet corn for our climate, we are now concentrating on the hard orange flints. The theoretical basis of the process "controlled polliration- pedigree-breeding" is easily explained. It consists in producing a popu- lation essentially homozygous for all desired characters, such as grain color and texture, ear size and form, plant height and relative position of ear (slightly above the middle of the plant); and heterozygous for the main factors giving vigor. That such a combination of homozygosis and heterozygosis is possible, was proved in indigenous corn which is on the one side very homogeneous for many seed and plant characters, but at the same time extremely susceptible to close inbreeding. In Piracicaba sweet corn which is a new synthetic variety we have started the routine work of selfing in order to produce ultimately hybrid seeds. 2. Chemical composition of grain. The following results were obtained in an analyses of a few of our varieties. The analyses were carried out by the chemists of the "Refinacoes de Milho Brazil, S.A.n in Sao Faulo, Hard Flint Dent C ateto Cateto Dente Dente P-104 P-114. P-111 P-113 Water (Umidade) % 1 2. SI 12.93 13. A5 13 .61 Irotein (Proteina) % 10.33 8 .5 8 3.8^ 8 .8A Oil (Oleo) % A.20 A.21 3.92 A.52 Sugar (Aciicar) % 0 .6 0 0 .6S 0.83 0.79 Dextrin (Dextrina) % 1 .5 8 1.A5 2 .0 0 1.80 Starch (Amido) % 66 .98 6 8 .60 67.71 66.89 Fiber (Fibra) cfn 2.15 2.25 1.95 2.15 Ash (Ginza) &/P 1.35 1 .3 0 1.30 1 .A0 Total cfP 100 .00 100 .00 100 .00 100 .00 Sweet Corn Piracicaba White Orange Horticulture Umidade 1 1. AS 11.63 11.95 Proteina 11 .21 12 .61 11 .56 Oleo 7 .6 1 6.7A 7.99 Acucar 3 .8 6 3.53 3 ,2 1 Dextrina 22 .36 22.78 23.63 Ami do 38.38 38 .01 36.15 Fibra 3.10 2.80 3.25 Cinza 2 .0 0 1 .9 0 2.25 Total 100 ,00 100 .00 100.00 673 Note: The three samples of sweet corn contain about five to six per cent of soluble starch, included in the total starch content. The analyses were carried according to "Food Inspection and Analysis” by Albert E. Leach, S.B. Fourth, 4-th edition, p, 304. There is evidently a very pronounced variation in oil. and protein content. Piracicaba sweet corn contains twice as much oil (seven per cent) as the flints and dents. Tue protein content is also rath-v high: 12 per cent of total weight or 13*5 per cent of day weight in sweet corn and 10 per cent in total weight or 11.b per cent of dry weight nr one of the hard flints. We hope to be able to carry out the analyses on si larger scale this year. 3• Resistance against the grain weevil and moth. A series of observations have shown beyond a doubt that one type of yellow dent (Monte Olimpo Pill) is relatively less attacked by these insects. The studies arc*being continued. 4. Linkage tests. The collection of linkage tests is now in the hands of Mr. Nelson Kobal, in continuation of the work by Dr. Graner who has left our Department, Some new lines have been incorporated and others are being constructed. We hope to furnish next year a complete list of our stocks. We expect also to be able from now on to furnish limited numbers of segregating ears for class work. 5. Tunicate. The work on South American Tunicate is practically concluded. There seems to be no essential difference, either genetically or in̂ phenotypic variability, between pcd corn from Sao Paulo, Minas Gerais or Bolivia. There cannot be any doubt, as far as the seed formation in the tassel is concerned, that there is no difference between homozygous and heterozygous pod corn* Thus, there should not exist any difficulty in maintaining homozygous pod corn through the seeds in the tassel, without the necessity of using in addition a tassel seed factor. 6 . Collection of indigeneous corn. The studies on authentic indigeneous corn are being continued and I hope to publish soon the first results, together with Dr. Cutler. There seems now to be little doubt that one may classify to some extent native corn in accordance with the grouping of the Indian tribes. The main bulk of our collection has been furnished by tribes of the Tupi- Guarany group. There is comparatively little difference between the types^ cultivated by the Emeremhon (north of the smouth of the Amazon), the Cayabi and other tribes (North Mato-Grosso, almost in the middle of Brazil), the Paragayans and the Chiriguanos (Northern Argentina)* The predominant- types are: Soft large-grained yellow (aleurone color); semi-hard white; 674 orange, variegated or red pericarp with some tendency towards dent. There are two rather primitive types; the large ears with flexible rachis and half-submerged grains from northern Mato-Grosso (Caiabi and Bororo Indians) and the small grained pointed pop corns of the Tupi-Indians, v/hich contain many "Tripsacoid" characters. Both the corn cultivated by the Chavantes of Central Brazil and numerous types cultivated by the Cainguang of Parana in the South are completely different, without the predominance of yellow and orange types. No explanation has as yet been found with regards to the hard orange flints called in the Argentine and Urugaya "Coloradon s" '’Quarantine11, and in Sao Paulo "Cateto". It may be extracted H:orn crosses of soft yellow and pointed pop. The genetical analysis of the material is being continued. In the color of red or purple (Pr/pr) aleurone as contrasted to colorless, at least three factors are Involved, one the dominant inhibitor Ci. There is at least one dominant inhibitor of yellow endosperm in pointed pop. Floury has more often a polyfactorial basis, rather than the simple fl gene, flaxy seems rather common. Nothing as yet can be stated with certainty about the large number of plant, cob and glume colors. Rose or wood-colored husks are due to ne?/ alleles of the P-series. The Mendelian ratios in Paraguay corn are all perfectly normal. In Bororo corn a gametophyte factor in the IX chromosome causes a defi- ciency or excess of recessives. 7. Cytology and studies on sterility. The material from the margins of the Amazon River is charac- terized by a considerable sterility and we hope to decide this year whether it is simply phenotypic or is a cytological complication. In several lines of indigenous corn the pollen is heteromorphic or dimorphic. In Cateto the frequency of different types of defective seed is remarkable. Nothing is known as yet about the frequency of B-chromosomes in this material, though we hope to get fuller information next year. 8. Origin of corn. Since full accounts have been published no details need be given. Accepting the eastern foothills of the Andes from Peru-Acre down to the Chaco as the center of origin, there are evidently two main centers of domestication: The Quechua group in the Andes and the Tupi-Guaranis in the plains. This year new material from outside these regions will be studied; material from Southern Brazil and, in the north, material from Colombia. 9. Relations between corn and teosinte. Both comparative morphological and genetic studies convinced me that teosinte is an independent genus, different from both Zea and Tripsacum. A full account is under publication. 675 The genetical analysis of Zea-Euchlaena hybrids continues. The phenotype of the and the segregation in the F2 depend’to a large extent upon the varieties used in the cross. Corn characters are less dominant in the order: Piracicaba Sweet, Paulista Pod, Paulista Pointed Pop; and teosinte characters are less dominant in the order: Mexican teosinte and Guatemala teosinte. In the F2 and subsequent generations many new combinations have appeared and I am trying to stabilize them; especially intermediate types and what may be called new teosinte "varieties”♦ Among the attempted com- binations one may be especially interesting: The combination of corn ear characters and the resistance of teosinte against inbreeding. The photo-thermo-periodicity of Euchlaena is rather interesting. Using earliness in flowering as a measure, we may establish generally the following order from the earliest to the latest: Mexican teosinte, Fp, Corn F-p and Guatemala teosinte. However, in the very rainy summer of 194-5 and. 1946 the order was maintained with one exception. Mexican teo- sinte and all teosinte-like segregates in F2 or later generations became as late as Guatemala teosinte or later still, some not flowering at all; while the F^ hybrids retained their relative position as indicated in the sequence above. The corn-r-like segregates and the intermediate forms be- haved more or less like the Fj hybrids. The analysis of individual gene segregations is under way 7/ith the intention of determining the intensity of gametophyte and of zygote elimination both of which are considerable. 3-0. Publications. Since all of our papers have been published in Journals v/ith a limited distribution, I am including a list as follows: Published papers. 1933 - F. G. Brieger - Problemas de melhoramento do milho. Revista Agr. 13:3-18. F. G. Brieger - Hibridos de milho com referenda especial a precocidade. Revista Agr. 13:3-13* F. G. Brieger e E. A. Graner - Variacoes quantitativas do milho "Santa Rosa". Revista Agr. 13:3-24. F. G. Brieger e E. A. Graner - Analise da precocidade no milho. Revista Agr, 13:3-17. 1943 - F. G. Brieger - Origem do milho. Revista Agr. ISs409-418. E. A. Graner - Endosperma amarelo do milho. Revista Agr. 18:443- 445. 1944 - F. G. Brieger - Estudos experimentais sobre a origem do milho. Anais Escola Sup. Agr. "Luiz de Queiroz", It226-278. E. A. Graner e G. 0, Addison - Meiose em Tripsacum australe Cutler e Anderson (T.dactyloides subsp-hispidum Hitchcock). Anais Escola Sup. Agr. "Luiz de Queiroz", ]_; 213-224, 1945 - F, G. Brieger - Estudos geneticos sobre o milho tunicata. Anais Escola Sup* Agr. "Luiz de Queiroz". 2^211-238. 676 F; G. Brieger - Competicao entre Megaspbrios era Milho# Anris Escola Sup* Agr. ,fLuiz de Queiroztf* 2:239-267. F. G. Brieger - Estulos sobre a inflorescencia de milho com referenda especial aos problemas filogeneticos. Bragantia* jn 659-716. H. C. Cutler - Espiguetas de dois graos no milho* Anais da Escola Sup. Agr. MLuiz de Queiroz". 2*423-430. F. G. Brieger 1. The al gene (yj) is seven units from lg] in chromosome 2. Its locus in relation to Ig-] and gl9 is: j___|________________ __L al lg, gl2 i--- — v— -- — " 7 19 2. The ŷ . gene of Dr. A. M. Brunson, white seeds and albino seedlings and is a new complementary to and Y^« Crosses with y^ and y^ . gave the following results: (a) Y ]_}r]_ Y^ Y^ Y yy yB nbn) & Total Pedigree Seedlings obtained ofClasses Seeds (1946) Green Albion (y7) seedlings Yellow-orange 240 231 5 236 11-19 ® ( Lemon-yellow 101 5 70 75 1 (Bn) 1̂ White 100 59 25 84 Total 441 295 100 395 (b) l3l.3l5y^jZrfi^n) © Total Fedigree Seedlings obtained ofClasses Seeds (1946) Green Aljpes plants as on normals. Defective and normal caryopses increase in weight at the same rate up to nine days after polli- nation. At 12 days the defective kernels have fallen slightly behind the normals in dry weight. The difference is much larger at 16 days, and continues to increase rapidly up to 2A days beyond which time the defec- tives make little growth. Histological studies reveal a relationship between the initial divergence in weight of the two classes of kernels and the differentiation of an absorbing region in the endosperm. Between six and 12 days the cells on the basal surface of the endosperm facing the placental region in normal kernels become elongated, the nuclei move to the inner end of the cells, and the cytoplasm assumes a dense, fibrillar appearance. The basal cells of the endosperm in defective seeds do not become similarly trans- formed into absorbing elements, Rather, they enlarge about equally in all dimensions and become highly vacuolate, A few days later the cells in̂ this region in defectives begin to break down. Eventually many cells in the basal area and in the adjoining central region of the endosperm col- lapse and thus become entirely nonfunctional in the transfer of nutrients to the seed. The parenchymatous cells of the placenta are quickly and exten- sively depleted of their total contents by the regularly differentiating normal endosperm. The corresponding cells in kernels possessing defective endosperms are more slowly and less completely depleted. The difference appera's to be a direct function of the absorptive capacities of the normal nnd defective endosperms. A definite conclusion cannot be reached from the available data whether the de-̂ y allele exerts a direct parallel action on endosperm and embryo, or acts directly on the endosperm only. The severely restricted development of the defective endosperm in itself is sufficient to account for the failure of many of the associated embryos to reach a viable con- dition and for the others to yield weak seedlings. The somewhat shorter stature of adult de_1? plants, as compared with their normal sibs, may be due either to the handicap incurred at the seedling stage because of poor seed development or to this factor plus a continuing but only mildly del- eterious effect of the de-̂ y allele on later growth. R. A. Brink D. C. Cooper 681 II. MAIZE PUBLICATIONS — 1946 (Including certain. 194-5 publications not previously listed and some early 194-7 publications.) Altstatt, George E. A new corn disease in the Rio Grande Valley. Plant Dia. Reporter 29(20): 533-534-. 1945. Anderson, E. and J. J. Finan. A preliminary check-list of pop corn varieties, Mo. Bat. Gard. Mimeographed pp. 16. 194-6. A„ . . Corn before Columbus. Pioneer Hi-Bred Corn Company Misc.. Pub. 1947. . . Maize in Mexico - a preliminary survey. Ann. Mo. Bot. Gard. 33:"l47-247. 1946. Anonymous. Corn hybrids still increasing: Release acreage for other crops. U.3.D.A. Bur. Agr. Ec. Mimeographed pp. 2. JuJLy 11,1946. _________. Better corn from improved parents. Seed World 60(5):42. 1946. _________. Corn goes home; Iowa State College Guatemala Tropical Research Center. Tifne 47:90 March 4? 1946. _________. Corn hybrids recommended for production in Ontario - 1946. Suppl. Pamph. Dorn. Can. Dept. Agr. 22: pp. 2. 1946. _ _______ . Emergency storage of corn. Breeders Gaz. 111(11):9« 1946. _________. Hybrid corn: Percentage of total corn acreage planted with hybrid seed, by states, 1933-1946. Crops & Markets 23(7):123. 1946. _________. New findings on corn breeding. Seed World 59(6):5&~59. 1946. ______ . Signal growth potential soaked corn grains. Sci. N.L. 49:361. June S, 1946. _________. Sweet corn in Dixie. Market Growers Jour. 75(2):27 ff. 1946. _________. The prolific hybrids. The Farm Quarterly 1(4): 4-4 ff* 1946. Arnold, E. H. Maize. N. Zeal. Jour. Agr. 73(l):59? 61. 1946. Barre, H. J, Drying seed corn ears with forced heated air. Elec. World 125:103^104. April 27, 1946. Bliss, Laura and Nellie M» Naylor. The phosphorylase of waxy maize. Cereal Chem. 23(2):177-186. 1946. Borlang, N. E. Diseases of teosinte in Mexico. Phytopath. 3 6: p. 395• 1946. 682 Burnham, C. R. ’’Oenothera” or multiple transl cation method of establish- ing homozygous lines. Jour. Amer. Soc. Agl'on. 38(8);702-707. 1946- Caldwell, A. C. and J-.,-M> MacGregor. Potash-nitrate relationship in corn as revealed by tissue tests. Better Crops 29(10):13-14+. 1945. Cameron, James W. A study of the genic control of carbohydrates in ma^ze endosperm. Genetics 32(1):81. 194-7. Carter, G. F. Origins of American Indian agriculture; races of corn. Araer. Anthrop. 4S(l):2-10. 194-6. Role of plants in geography; corn regions in the Americas. Rev. 3^(1): 122-130.. 194-6. Cates, J. S. Raising corn with less work. Country Gent. 116:18+. Oct, 194-6. Choudhri, R. S. and R. Krishan. Sex differentiation m Sea Mays. Sci. & Culture 11(9):472-4-76 1946. Crosier, Willard. Chemical control of seed-borne fungi during germination testing .of peas and sweet corn. Phytopath. 36(2):92-99. 1946. ________________, and Stewart Patrick. Arasar for control of fungi in germinating corn seed. Phytopath. 3'o{2j% 162-164* 1946. Cunningham, J. C. Your corn has come 0. long way» Successful Parmer 44 (12):28-29. 1946. Curtis, J. J. and F. R. Earle. Analyses of double-cross hybrid corn varieties produced on farms. Cereal Chem. 23(l):88—96. 1946. Cutler, Hugh C. Races of maize in South America. Bot. Musy,hedflets, Harvard Univ, 12(8):257-291. 1946. Davis, B. H. and C. M. Kaenseler. Seed protectants on sweet corn in relation to plant vigor. Plant Dis. Reporter 30(6):199-200. 1946. Dodds, K. S. and N. W. Simmonds. A cytological basis of sterility in Tripsacum laxum. Ann. Bot. 10:109—116. 1946. Dody, D. M., Merlin S. Bergdoll, Harold A. Nash and A. M. Brunson. Amino acids in corn grain from several single cross hybrids. Cereal Chem. 23(2):199-209. 1946. Dungan, George H. Distribution of corn planes in the iielo.. Jour. Amer. Soc. Agron. 3 8(4 ):318-324. 1946. _________ , J. II. Bigger, A. L. Lang, Benjamin .Koehler and R. W. Jugenheimer. Illinois hybrid corn tests, 1945. Bui. Illinois Agr. Exp. Sta. 517:225-256. 1946. 683 Eaton, Frank M. and Neil E, Rigler. Influence of carbohydrate levels and root-surface microfloras on Phymatotrichum root rot in cotton and maize plants. Jour. Agr. Res. 72(1): 137-162. 194-6. Elliott, Charlotte and Merle T. Jenkins. Helminthospcrium turcicum leaf blight of corn. Phytopath. 36(8):660-666. 194-6. Eyster, H. C. Theoretical aspects of hybrid corn genetics and hybrid vigor. Genetics 31(2):215. 194-6. Fogei, Seymour. Allelic differentiation and correlations in gene action. Genetics 32(l):36. 1947. ____ . Gene action and histological specificity of pigmentation patterns of certain R alleles. Genetics 31(2): 215. 1946. _____________ . Gene action and the course of anthocyanin synthesis in certain R alleles (in maize). Genetics 31(2):2l6. 1946. Giles, Norman H., Jr., P. R. Burkholder, Ilda McVeigh and Katherine S. Wilson. Comparative studies on the B-vitamin content of trisomic and disomic maize. Genetics 31(2):216-217. 1946. Gilly, G. L. and I. E. Melhus. Distribution and variability in teosinte. Amer. Jour. Bot. (Suppl.) 33:235. 1946. Graner, E. A. Testes para a localizacao de fatores geneticos no milho. Testes de ligacao. Rev. Agr., Piracicaba 21:8—20. 1946. Green, John M. Comparative rates of pollen tube establishment in diploid and tetraploid maize. Jour. Hered. 37(4):117-121. 1946. * Haagen-Smit, A. J., W. B. Dandliker, S. II. Wittwer and A. E. Murneck. Isolation of 3-indolacetic acid from immature corn kernels. Amer. J our. Bot. 33(2):118-120. 1946. Hanson, L. E. Waxy corn versus non-waxy corn for growing fattening pigs in dry lot. Jour. Animal Sci. 5(2):36-41» 1946. Harland, S. C. A new method of maize improvement. Trop. Agr., Trinidad 23(6):114. 1946. Kayes, H. K., E. H. Rinke and Y. S. Tsiang. Experimental study of conver- gent improvement and backcrossing in corn. Tech. Bui. Minnesota Agr. Exp. Sta. 172.1-40. 1946. Kayne, D. 7/. Relation between number of ears opened and the amount of grain taken by red-wings in corn fields. Jour. Agr, Res. 72(5): 289-295. 1946. Heyne, E. G., A. L, C?agT * G.-R.' Porter., VI, 0. Scott, anci G. D. Davis. Kansas corn tests, 1945. Bui. Kansas Agr. Exp. Sta. 32^ pp. 40. 1946. 684 Hoekzema, J. P. Hybrid seed corn takes over in Guideland. Farmers1 Guide 102(9):18. May 1, 1916. Hull, Fred K. Overdominance and corn breeding where hybrid seed is not feasible. Jour. Amer. Soc. Agron. 38(12): 1100-1103. 194-6. ____________. Plant breeding in relation to soil fertility and climate. Better Crops 30( 10): 12-14.. 194-6. ________ _ __• Regression analyses of corn yield data. Genetics 31(2): 219. 194-6. Hurt, E. F. Maize for table and poultry feeding, a dual-purpose hybrid. Jour. Royal Hort. Soc. 71:138-141. 1916. Jenkins, M. T. Report of the First Northeastern Corn Improvement Confer- ence. Connecticut Agr. Exp. Sta,, New Haven, Connecticut. Feb. 2-3, 194-5. Div. Cereal Crops Dis., Bur. PI. Ind., Soils, Agr, Eng., PI. Ind. Sta., Beltsville, Maryland, pp. 21. 194.5. (Mimeographed), ____________ ,. Report of the Fourth Southern Corn Improvement Conference. Birmingham, Alabama. Jan. 24.-25, 194-5. Div. Cereal Crops Dis., Bur. PI. Ind., Soils, Agr. Eng., PI. Ind. Sta., Beltsville, Maryland, pp. 4-3. 194-5. (Mimeographed). Keeney, L. G. Fire hazards relating to hybrid seed corn. Agr. Eng. 26 (2):71-76. 1915. Kunze, R. E. New slant on hybrid seed corn. Ohio Farm Bur. News 26(2): 30-31. 1916. Lang, A. L. Effect of fertilizer and soil fertility on corn quality. Seed World 61(2):18-21. 1917. Langham, D. G. and others. El maiz en Venezuela y su mejoramiento. Publ. del Ministerio de Agricultura y Cria Bui. 1. pp. 59. May, 1915. Laughnan, John R. Chemical studies concerned with the action of the gene Aq in maize. Genetics 31(2):222. 1916. Livingston, J. E. Charcoal rot of corn and sorghum. Res. Bui. Nebraska Agr. Exp. Sta. 136. 1-32. 1915. Lowe, Jeanette and Oliver E. Nelson, Jr. Miniature seed — a study in the development of a defective caryopsis in maize. Genetics 31(5): 525-533. 1916. Malaini, C. Studio comparativo sui granturchi coltivati nelle Vepezie nel 1912 - Conunicazione preliminare, Genetica Agraria, Rome 1:95-102. 1916. Mangelsdorf, Paul C. The genetic nature of teosinte. Genetics 32(1): 95-96. 1917. 685 Mangelsdorf, Paul G. Thp origin and evolution of maize. Advances in Genetics. Vol. 1 Academic Press, New York. 1947, ___________________ and R. G. Reeves, The origin of maize: Present status of the problem. Amer. Anthrop* 4-7(2): 235-24-3• 194-5• Marino, A. E. Aspectos de calidad en el maiz argentine, Granos 9(4/6): 21-27. 1945. Mather, K. and E. C. Barton-Wright. Nicotinic acid in sugary and starchy maize. Na ture (London) 157(3978):109-110. 1946. Mazoti, L, B. Contribucion a la genetica del maiz. Rev. Argent. Agron. 12:174-202. 1945. McClintock, Barbara. Cytogenetic studies of maize and neurospora. Carnegie Inst, of Washington Year Book 44? for the year 1944-45: 108-112. 1945. McKecn, C. J. Maize seed selection. Qd. Agr. Jour. 60:261-268. 1945. McLaughlin, J. Harvey. Southern cooperative corn disease research committee report for 1945. Plant Dis. Reporter 29(28):722-729* 1945. McVickar, M. H. and G. M. Shear. Variations in response of different varieties and hybrids of field corn to planting rate. Jour. Amer. Soc. Agron. 38(10):933-935. 1946. ______________ and T. M. Starling. The 1945 official Virginia varietal tests of corn hybrids, barley, oats and wheat. Virginia Agr. Exp. Sta. Bui. 383. 1-16. 1945. Melhus, I. E., G. Semeniuk, J. R. Wallin, G. M. Watkins-and G. J. Goodman. Comparative development of some United States, Mexican and Central American corns at different latitudes and altitudes. Amer. Jour. Bot. (Suppl.)33:220-221. 1946. Miles, G. F. Slurry method for treating seed corn. Ag. N. Letter 14(7): 71-74. 1946. Miles, S. R. Performance of corn hybrids in Indiana, 1937-1944. Indiana Agr. Exp, Sta. Bui. 511. 1-53. 1946. Myburgh, S. J. Biological values of the proteins of some South African (whole seed) maize varieties. Onderstepoort J. 21:59. March, 1946, Nagel, C. M. and G. Semeniuk. Some mold-induced changes in shelled corn. Plant Physiol. 22(1): pp. 20-33. Jan. 1947. Nelson, 0. E.,Jr., and H. S. Burr. Growth correlates of electromotive forces in maize seeds. Proc. Nat. Acad. Sci., U.S.A. 32(4): 73-84. 1946. 686 Phirmey, B. 0. Cell length in the parenchyma of the midrib of normal and dv/arf-1 maize at various stages of development. Amer. Jour, Bot. (Suppl.) 33:222-223. 194.6. Firovano, Alberto. Progress and directives regarding electro-genetics. Internatl. Rev. Agr. 36sl73T-189T. Nov,/Dec. 1945. Plank, II. K. Control of storage insects in corn seed. Jour*. Econ, Entom. 39(6):314-319. 1946. Porter, John W ., F, M. Strong, R. A. Brink and N, P. Neal, Carotene content of the corn plant. Jour. Agr. Res, 72(5):169-187. 1946. Reeves, R. G. Methods for studying the maize ear, Bot. Gaz. 107(3):425. 1946. Rhoades, M. M. Crossover chromosomes in unreduced gametes of asynaptic maize. Genetics 32(1):101. 1947. Richey, Frederick D. Corn cob fur. Jour. Hered. 37(G):251-252. 1946. ______ ____________ . Hybrid vigor and corn breeding. Jour. Amer. Soc, Agron. 38(9):833-841* 1946. ___________________, Multiple convergence as a means of augmenting the vigor and yield of inbred lines of corn. Jour. Amer. Soc. Agron, 38(10):936-940. 1946, Robinson, J. L. and F, Reiss, The 1945 Iowa corn yield test, Bui, Iowa Agr, Exp. Sta. P79. 600-642. 1946. * / * Sanchey, Colin S. El maiz y la experimentation agricola. Campesino Morel 1(20/21):1,11-12. 1946. Sass, J. E. Development of endosperm and antipodal tissue in 11 Argentine waxy” maize. Amer. Jour. Bot. 33:223. 1946. Schaible, P. J. Composition of certain hybrid and open-pollinated corns and their performance in poultry rations. Michigan Agr. Exp, Sta. Quarterly Bui, 29:31-39. 1946. Schopmeyer, K. H. Amioca, The starch from waxy corn. Food Indust. 17(12) 1476-1478. 1945. Semeniuk, 3., C. M. Nagel and J. C. Gilman. Observations on mold develop- ment and deterioration of stored yellow-dent shelled corn. Iowa Agr. Exp. Sta. Res. Bui. 1946. (Submitted for publication,) Shedd, C. K. Resistance of ear corn to air flow. Agr. Eng. 26(l):19-20, 23. 1945. Shull, George Harrison. Hybrid seed corn. Sci. 103(2679):547-550. 1946, ______________________. Pure line method of corn breeding. Seed World 59 (6):8-11. 1946 687 Singleton, V7, Ralph. Inheritance of indeterminate growth in maize. Jour. Hered. 37(2):6l-64. 1943. ___________________• "Long Husk” sterility in maize. Jour, Hered. 37(1): 29-30. 1946. Smith, G. M. Improved Golden Cross Bantam and Purgold sweet corn. Indiana Agr. Exp. Sta. Bui. 513. 1-4, 1946, Smith, Luther. ■ A comparison of the effects of heat and X-rays on dormant seeds of cereals, with special reference to polyploidy. Jour. Agr. Res. 73(4):137-153, 1946, Sprague, G. F. The experimental basis for hybrid maize, Biol, Rev. Cambridge Phil. Soc. 21(3):101-120. 1946. Stabler, L. J. Spontaneous mutation at the R locus in maize. J, The aleurone color and plant color effects. Genetics 31(4);377-394. 1946. Standen, J, K. A toxic substance occurring in certain maize cobs, Contr. Boyce Thompson Inst. 14(4 ):277-281. 1946, Steel, K, Revolution in the corn belt, Harper 191:159-163. August, 1945. Sylvain, Pierre Georges. Correlative development of the ear shoot of maize. Iowa State Coll. Jour. Sci. 20(1)s49-52, 1945, Thone, F. Hybrid corn. Sci, N, L. 50;222, October 5, 1946. Ullstrup, Arnold J. An undescribed ear rot of corn caused by Rhysalospora zeae. Phytopath. 36(3): 201-212. 1946. __________________. and Arthur' M. Brunson. Linkage relationships of a gene determining susceptibility to a disease in corn. Phytopath. 36:412. 1946. Viets, F. G., Jr., A. L. Mcxon and E. I, T/hitehead. Nitrogen metabolism of corn as influenced by ammonium nutrition. Plant Fhvsiol, 21 (3):271-289. 1946. ________________. The role of amino acids and amides in the metabolism of ammonium absorbed by Zea mays. Sci. n.s. 102:587-589. 1945, Walker, C. Maize growing for grain. New Zealand Jour. Agr. 72:281-299. 1946. Walter, E. V. and Arthur M. Brunson. Selection for aphid resistance within inbred lines of maize. Jour, Amor. Soc. Agron. 38(11): 974-977. 1946, Wang, F. K. Erabryological development of inbred and reciprocal hybrid Zea mays L, Amer. Jour. Bot, (Suppl.)33:224, 1946. 688 Washko, J. B. Potash deficiency in growing corn. Com. Fert. V3:32. 194-6. Weatherwax, P. Corn for morphological and genetic work. Genetics 31:23 1946. Weaver, harry Lloyd. A developmental study of maize with particular reference to hybrid vigor. Airier. Jour. Bot. 33(7): 615-624. 1946. Wernharn, C. C. Three hitherto unreported diseases of' corn in Pennsylvania. Plant Dis. Reporter 30(1-/ 26-28. 1946. Wiidakas, W. and L. A. Jensen. 1945 hybrid corn field trials. Agron. Miraeo. Cir. North Dakota Agr. Exp. Sta. 77. pp. 20. 1946. 689 V Jt 690 ANNOTATED BIBLIOGRAPHY Coe, E. 2009. East, Emerson, and the birth of maize genetics. Pp. 1-15, In J.E. Bennetzen and S. Hake (Eds.) Hand- book of Maize, Genetics and Genomics. Springer Science & Business Media, LLC. Coe, E.H. and L.B. Kass. 2005. Maize Genetics Cooperation News Letter files: Expanded chronological list of ma- terials and related cooperation. Maize Genetics Cooperation Newsletter 79 (Oct. 31): 72-76; available online April 2005: http://mnl.maizegdb.org/mnl/79/06CoeKass.htm (reprinted this volume-see Appendix I). Cook R.C. 1932. The Genetics Congress. Journal of Heredity, Vol. 23 (No. 9, 1 Sept.), pp. 355-360 [includes three figures, 10, 11 & 12, the latter is the numbered group photo and IDs] (Cook’s summary of the 1932 meeting; not free access). Crow, J.F. 1992. Sixty Years Ago: The 1932 International Congress of Genetics. Genetics Vol. 131 (August): 761-768. http://www.genetics.org/content/genetics/131/4/761.full.pdf [Note that Fig. 2, The Executive Council, is not from Cook 1932, J of Heredity.] [Attendees in the group photo are identified in Figure 3; See Maize Genetics Coopera- tion Newsletter, eCommons, for image scanned from a photo salvaged from NCSU by Ed Buckler]. International Congress of Genetics Records (1929-1932), #21/28/902. Division of Rare and Manuscript Collec- tions, Cornell University Library. https://newcatalog.library.cornell.edu/catalog/3074127. International Congress of Genetics Collection (1930-1932), History of Science arX6425 ++. Division of Rare and Manuscript Collections, Cornell University Library. https://newcatalog.library.cornell.edu/catalog/5181099 [In- cludes International Congress of Genetics (6th, 1932: Ithaca, N.Y.). Daily news bulletin, Genetics Congress quar- terly]. Jones, D.F. (Ed.) 1932. Proceedings of the International Congress of Genetics, Ithaca, New York, 1932, Volume 1, Transactions and General Addresses, i–xii, 1–396, Index i-xxxix. George Banta Publishing Co. Menasha, Wiscon- sin, USA [Attendees identified in the group photo can be found on pp. 48-49; Photo link to Volume I facsimile (excludes Index): http://www.esp.org/books/6th-congress/facsimile/] Jones, D.F. (Ed.) 1932. Proceedings of the International Congress of Genetics Ithaca, New York, 1932, Volume 2, Condensed Articles and Descriptions of Exhibits, i-xvi, 1–405. [24–31 August 1932, Foreword dated 26 July 1932] George Banta Publishing Co., Menasha, Wisconsin, USA. Kass, L.B., C. Bonneuil, and E.H. Coe, Jr. 2005. Cornfests, cornfabs and cooperation: The origins and beginnings of the Maize Genetics Cooperation News Letter. Genetics 169 (April): 1787-1797; online May 6, 2005: http://www. genetics.org/content/169/4/1787.full.pdf+html; (Reprinted this volume, see Appendix I). Maize Genetics Cooperation News Letter [1-21]. eCommons: https://ecommons.cornell.edu/handle/1813/58745 Three images are also included at this webpage: Sixth International Congress of Genetics (ICG), 1932 group photo; T.H. Morgan and R.A. Emerson, at ICG 1932, Willard Straight Hall; and 1932 ICG Executive Council. All images were scanned from photos rescued from a storage closet at NCSU, by Edward Buckler. The photos are believed to have been originally owned by C.H. Bostian (see Introduction). Maize Newsletter Archives, MaizeGDB, https://www.maizegdb.org/mnl; Many MNLs available here were retyped from originals; many items, especially of early volumes, are not verbatim, e.g., page numbers and contributors’ affiliations are not listed. [Also, some volumes and dates on the website are not consistent with hard copy cover dates.] Morgan, T.H. 1932. The Rise of Genetics, Excerpts from the Address of the President of the Sixth International Congress of Genetics at Ithaca. Journal of Heredity Vol. 23 (No. 9, 1 Sept.), pp. 337-343 [Not free access; pdf of this article includes the Volume’s frontispiece, titled “At Ithaca”; a photo of Morgan and Emerson at the 1932 Interna- tional Congress of Genetics, is included in this MNL Anniversary book-see frontispiece]. B.1 Portwood J.L. II, Woodhouse M.R., Cannon E.K., Gardiner J.M., Harper L.C., Schaeffer M.L., Walsh J.R., Sen T.Z., Cho K.T., Schott D.A., Braun B.L., Dietze M., Dunfee B., Elsik C.G., Manchanda N., Coe E., Sachs M., Stinard P., Tolbert J., Zimmerman S., Andorf C.M. 2019. MaizeGDB 2018: the maize multi-genome genetics and genom- ics database. Nucleic Acids Research. Volume 47, Issue D1, 08 January 2019, Pages D1146–D1154, https://doi. org/10.1093/nar/gky1046 (published online: 08 November 2018). Rhoades, M.M. Biographical Memoir of Rollins Adams Emerson, 1873-1947. National Academy of Sciences (USA). Biographical Memoirs Vol. XXV [25]: 313–323. http://www.nasonline.org/publications/biographical-memoirs/ memoir-pdfs/emerson-rollins.pdf B.2 APPENDIX I Introduction to reprint of Kass, L.B., C. Bonneuil, and E.H. Coe, Jr. 2005. Cornfests, cornfabs and cooperation: The origins and beginnings of the Maize Genetics Cooperation News Letter. Genetics 169 (April 1): 1787-1797; online May 6, 2005: http://www.genetics.org/content/169/4/1787.full.pdf+html [Reprinted with permission of Genetics Society of America]. The following reprinted article provides a perspective on the origins and beginnings of the founding of the Maize Genetics Cooperation and its subsequent Cooperation News Letter. It describes how in the early 1920s, the Maize Genetics Cooperation (MGC) began in an informal way among R.A. Emerson and his students at Cornell Uni- versity. Emerson’s ethical and cooperative spirit paved the way for an expanded network of maize researchers who freely shared their materials and unpublished research, thus resulting in rapid progress in fundamental genetic research. The Maize Genetics Cooperation News Letter early volumes reprinted in this book provide documentation for the story told in this historical perspective. A.1 Copyright © 2005 by the Genetics Society of America Perspectives Anecdotal, Historical and Critical Commentaries on Genetics Edited by James F. Crow and William F. Dove Cornfests, Cornfabs and Cooperation: The Origins and Beginnings of the Maize Genetics Cooperation News Letter Lee B. Kass,*,1 Christophe Bonneuil† and Edward H. Coe, Jr.‡ *Department of Plant Biology, Cornell University, Ithaca, New York 14853, †CNRS, Centre Koyré d’Histoire des Sciences et des Techniques, 75231 Paris, Cedex 05, France and ‡United States Department of Agriculture-Agricultural Research Service, Plant Genetics Research Unit and University of Missouri, Columbia, Missouri 65211 IN the early 1920s, the Maize Genetics Cooperation who granted him funds to support his information and(MGC) began in an informal way among R. A. Emer- supply network in 1934. The work of Barbara McClin- son and his students. His ethical and cooperative spirit tock in cooperation with Beadle, Rhoades, Creighton, paved the way for an expanded network of maize re- Burnham, and others at Cornell between 1928 and 1934 searchers who freely shared their materials and unpub- resulted in a definitive correlation of chromosomes and lished research, thus resulting in rapid progress in funda- linkage groups in maize—ultimately published in 1935 mental genetic research (Coe 2001; Kass and Bonneuil by Emerson et al. The cytogenetics of maize was also re- 2004). viewed in that year (Rhoades and McClintock 1935). The first letter summarizing both published and un- The exhibits that Emerson submitted to support his published maize linkage data was compiled by Emerson Rockefeller Foundation grant included a historical sum- and his student George Beadle and sent to students of mary of the MGC and MNL. These documents allowed maize genetics on April 12, 1929. This communication us to reconstruct the events that established these im- was an outcome of a “cornfab” held in Emerson’s hotel portant resources for the maize genetics community. room in December 1928, during the annual American Emerson’s legacy lives on in the cooperative spirit of Association for the Advancement of Science (AAAS) maize researchers and in the News Letter he founded meetings. The “Historical Notes on Maize Cooperation” 75 years ago. identifies Emerson’s 1929 communication as the first At the 1932 ICG held in Ithaca, New York, Rollins Maize Genetics Cooperation News Letter (MNL; Emer- Adams Emerson (Nelson 1993), Head of the Depart- son 1940). Beadle was the first secretary of the MGC ment of Plant Breeding at Cornell University, gave an and he solicited material for additional summaries of opening address titled, “The Present Status of Maize linkage data, which were distributed in two parts in Genetics.” In his introduction he declared, “I cannot 1930. Rhoades succeeded Beadle as secretary and con- refrain from noting here a very real advantage experi- tinued to summarize and publish the reports of coopera- enced by students of maize genetics . . . I am aware of tors in the MNL, which continues to be published annu- no other group of investigators who have so freely ally. shared with each other not only their materials but The cooperators met at the Sixth International Con- even their unpublished data. The present status of maize gress of Genetics (ICG) at Ithaca in 1932 and organized genetics, whatever of noteworthy significance it presents, a committee to establish the maize stock center at Cor- is largely to be credited to this somewhat unique, un- nell University and to seek funding for their enterprise. selfishly cooperative spirit of the considerable group of Emerson’s grant application to the National Research students of maize genetics” (Emerson 1932, p. 141; Kass Council (NRC) was denied and he was encouraged to 2001). apply immediately to the Rockefeller Foundation (RF), During this Congress, Emerson called a meeting of 45 students of maize genetics and formalized what would soon be called the Maize Genetics Cooperation. Following their meeting Emerson and his graduate stu- 1Corresponding author: Department of Plant Biology, 228 Plant Sci- ence Bldg., Tower Rd., Cornell University, Ithaca, NY 14853-5908. dent Marcus Rhoades issued on October 5, 1932, what E-mail: lbk7@cornell.edu has long been considered the first Maize Genetics Co- Genetics 169: 1787–1797 (April 2005) A.2 1788 L. B. Kass, C. Bonneuil and E. H. Coe Figure 1.—R. A. Emerson with former and current students and colleagues at Fernow Hall, Cornell University, January 1, 1922, follow- ing the AAAS meeting in Toronto, where the second “cornfest” was held. Back row, from left to right: Milislav Demerec, Sterling Emer- son, Ernest G. Anderson, and Charles Metz; front row, from left to right: Maxwell J. Dorsey, Sewall Wright, Rollins A. Emerson, Wil- liam Bateson, Claude Burton Hutchison, Calvin Bridges, Frank P. Bussell, and Lewis A. Eyster (with permission of Royse P. Mur- phy, Department of Plant Breed- ing, Cornell University; see also Provine 1986, p. 103). operation News Letter (Rhoades 1932a). Our research A. Kroch Library, Cornell University (CU) Library, Ith- (Bonneuil and Kass 2001; Coe 2001; Kass and Bon- aca, NY]. Soon afterward, Emerson arranged informal neuil 2004; E. H. Coe and L. B. Kass, unpublished “cornfests” in conjunction with the AAAS meetings. It results), which we offer in keeping with the long tradi- seems that Emerson organized these 10 years before tion of maize cooperation, provides a historical perspec- the famous “cornfab” held in his hotel room in New tive on the actual origin of the MGC and the beginnings York City in December of 1928, as recalled by Rhoades of the MNL, which was first issued in 1929. We present (1984). Emerson much earlier had invited Paul Weath- here the history of Emerson’s successful negotiations erwax of Indiana University to attend a “second corn- with the Rockefeller Foundation to fund his cooperative fest” along with the “general genetics section” he had enterprise at Cornell University following his unsuccess- planned for the AAAS meetings in Toronto in 1921. ful attempt to obtain funding from the NRC. Future Weatherwax apologized for not being able to attend Nobel laureates George Beadle, Emerson’s student, and (Weatherwax to Emerson, November 22, 1921, CU) but Barbara McClintock, Lester W. Sharp’s student and Bea- Emerson’s former and current students and colleagues dle’s collaborator, freely submitted their results to the joined him there and, following the meeting, held a MNL; this laid the groundwork for a similar publication, reunion on January 1, 1922, at Cornell (Figure 1). the Drosophila Information Service, for the Drosophila ge- The following winter, Emerson emphasized the im- neticists in March 1934 (Bridges and Demerec 1934) portance of agreeing on uniformity for factor notation and for the Worm Breeders Gazette, the community news- (gene symbols) and he set the tone for cooperating on letter of the roundworm biologists (Edgar 1975; Cohen this problem in a letter on March 7, 1923 (Emerson 1995), among others. We rejoice in the founding of 1923, p. 147), “To Students of Corn Genetics : . . . . It Emerson’s ideal and celebrate the 75th anniversary of seems wise to follow the notation used by the Drosophila the MNL. workers, tho, in some respects, their usage is perhaps no more nearly consistent than our own.” Emerson also asked his colleagues for assistance with numbering the EARLY COOPERATION maize linkage groups and requested advice on using bi- Cornfests—a cooperative enterprise to map maize: literal gene symbols: As early as November 1918, Emerson wrote to Donald Shall priority of publication of any linkage determine F. Jones at the Connecticut Agricultural Experiment the numerical order? Or shall the order be determined Station that he was “hoping that all the men in this arbitrarily? . . . I suggest . . . that we number the groups country who are working on related problems with corn in the order given by [William H.] Eyster and by [Claude B.] Hutchison as follows: 1-C-wx ; 2-g-R ; 3-su-Tu ; 4-B-Lg ; may cooperate to such an extent that we can cover the 5-Y-Pl ; 6-P-f . . . . It may be wise, however, to assign no field more quickly” [Emerson to Jones, November 8, numbers to groups other than the six listed above until 1918, Division of Rare and Manuscript Collections, Carl the newer groups have been tested further. Another prob- A.3 Perspectives 1789 Figure 2.—R. A. Emerson and members of the Synapsis Club, 1923. Herbert J. Webber started this student/faculty organization at Cornell in 1907, and Emerson continued and encouraged mem- ber participation (Department of Plant Breeding Records, Courtesy of the Division of Rare and Manu- script Collections, Cornell Univer- sity Library). Members are identi- fied from left to right (an asterisk designates corn researchers). Front row: William T. Craig, J. Randal Livermore, Ernest Dorsey, Frank- lin D. Keim, Robert D. Lewis, Laurens J. Henning, John P. Jones, *Helen A. Z. Trajkovich, G. V. Wazalwar. Second row: Frank P. Bussell, *Allan C. Fraser, Harry H. Love, *Rollins A. Emer- son, Clyde I. Myers, *Roy G. Wig- gans, *Lester W. Sharp, *Lowell F. Randolph. Back row: T. Sasaki, Archie F. Barney, Harold D. Brown, Leo A. Van Rooyen, *Pavao Kvakan, Andrew D. Suttle, Walter A. Burkholder, Lua A. Minns, Edward L. Proebsting, Clif- ford V. Kightlinger, Merl C. Gillis, and *Iang Chandrastitya. lem is bothering us. Shall we continue to use bi-literal 1924). In addition to Anderson and Lindstrom, several symbols for genes as we have usually done in the past other students pursued graduate work with Emerson [i.e., bl, blotched leaf], or adopt the recommendations of the Naturalist’s committee to use single letter symbols on corn genetics (including women and students from [i.e., b1]? If the corn men desire to stick to the use of bi- abroad, Figures 2 and 3): William H. Eyster, Milislav literal symbols, we shall probably have to refrain from Demerec (Figure 1), Helen A. Trajkovich, Pavao Kva- publishing in Genetics . . . but if the corn men think best kan, Thomas Bregger, Ivan F. Phipps, George W. Beadle, to adopt the plan followed by Genetics [using single letter Hsien W. Li, George F. Sprague, Johannes D. J. Hof- symbols], I shall use it (p. 149). meyr, Marcus Rhoades, Swarm Singh, Sylvia Allen, and Emerson ended his five-page review with words for con- others (R. P. Murphy, unpublished results; CU). tinued cooperation, “I am sending this to a considerable During the period 1918–1920, Emerson realized that number of corn genetics workers. When I have received he could not avoid investigating the linkage of maize, replies from the majority, I may want to refer some of our which was crucial both to closing the gap with Drosoph- problems to the Chairman of the Naturalist’s committee ila workers and to providing a deeper basis for the breed- with the suggestion that he consider the advisability of ing work on corn. Whereas from 1913 to 1928 Drosoph- referring it to the committee for consideration” (p. 149). ila linkage mapping remained the concern of a few Two of Emerson’s former students at Nebraska, laboratories (Wagner and Crow 2001), Emerson pro- Ernest G. Anderson (Figure 1) and Ernest W. Lind- moted the idea that maize genetic mapping should be strom, had followed him to Cornell in 1914 and contin- a larger cooperative enterprise (Kass and Bonneuil ued to work on corn problems after graduating. Stu- 2004), which would allow individuals to devote the best dents and established researchers from around the of their research time to more fundamental research country and throughout the world soon joined Emer- projects. Furthering this end, Emerson also developed son’s group and studied corn breeding and genetics at a regular collaboration and acted as advisor to the U.S. Cornell. C. B. Hutchison (Figure 1), a former Cornell Department of Agriculture (USDA) program in corn graduate, was appointed Professor of Plant Breeding in research from 1920 onward [U.S. National Archives and 1916. By 1921, he continued Emerson’s unpublished Records Administration (NARA), College Park, MD]. study of C-Sh linkage and established that Sh was part Several graduate students, including Barbara McClin- of the C-Sh-Wx linkage group (Hutchison 1921, 1922). tock, George Beadle, and Marcus Rhoades, were sup- When Allan C. Fraser (Figures 2 and 3) succeeded ported at Cornell by USDA funds, and some graduates Hutchison, he turned (from wheat) to maize (Fraser obtained jobs with the USDA, including Arthur M. Brun- A.4 1790 L. B. Kass, C. Bonneuil and E. H. Coe Figure 3.—R. A. Emerson, Mr. S. C. A. R. Crow, and students of corn genetics posing in front of the Plant Breeding shed near the Plant Breeding Garden at Cornell University, 1927 (see also Kass and Murphy 2003) (courtesy of William B. Provine). From left to right, front row: Hsien W. Li (China), Ivan F. Phipps (Austra- lia), Allan C. Fraser, George Bea- dle’s dog (Toto), George W. Bea- dle, and Harold B. Riley. From left to right, back row: Thomas Breg- ger, George F. Sprague, R. A. Emerson, S. C. A. R. Crow, Profes- sor Emerson’s dog, Roy G. Wig- gans, and Wiggans’ technician. son, Thomas Bregger, Lowell F. Randolph, Marcus trisomic ratios correlating genes with specific chromo- Rhoades, and George Sprague, all of whom contributed somes were major contributions to Beadle’s “Summary to the cooperative endeavors. of Data on the Independence of the Linkage Groups Following Emerson’s early work on multiple factor in Maize,” which Emerson distributed “To Students of inheritance (Emerson and East 1913), his maize genet- Maize Genetics” on April 17, 1930 (Emerson 1930a). ics school contributed concurrently to the progress of McClintock, then an instructor at Cornell, collaborating corn breeding and to general knowledge in genetics. with students George Beadle, Henry Hill, Harriet In this respect, Emerson’s program may be considered a Creighton, and Marcus Rhoades, and with Charles Burn- parallel to Thomas Hunt Morgan’s group [at Columbia ham, a visiting scientist, and others, began a golden age University and later at The California Institute of Tech- for maize genetics and cytogenetics at Cornell (Rhoades nology (Caltech)]. Emerson’s students had close scien- 1984). tific associations with the Drosophila geneticists and with At the Ithaca Congress in August 1932, Emerson could geneticists and cytologists at other institutions. Concepts, confidently present a genetic map with linkage groups methods, standard nomenclatures, along with students correlated with numbered chromosomes, thus setting the (including E. G. Anderson, M. Demerec, G. Beadle, and stage for further cooperative and significant contributions M. Rhoades) who were trained in corn genetics and to maize cytogenetics (Rhoades and McClintock 1935). later also worked on Drosophila, circulated between the Rhoades also organized a “living chromosome map” in two communities. Maize geneticists maintained strong which mutant plants were arranged according to their relations with Drosophila geneticists during the 1920s chromosomal positions (Crow 1992). (e.g., C. Metz, C. Bridges; Figure 1). This connection was due primarily to Emerson and his students, who kept Emerson informed about the exciting work that FOUNDING THE MAIZE GENETICS COOPERATION NEWS LETTER was progressing in these laboratories. Consequently, Cornell maize geneticists were aware that the use of By February 1934, Emerson had applied to the RF cytogenetics by Drosopholists had opened a fertile sec- for a grant-in-aid for support of work in collecting and ond front to tackle problems. disseminating maize stocks and information (CU). Em- Linkage groups: By 1928, however, significant general erson submitted a separate portfolio of exhibits (RF contributions to genetics from corn were quite limited exhibits A–J, Rockefeller Foundation Archives, Sleepy (McClelland 1930). Furthermore, maize linkage studies Hollow, NY) to document his application dated Febru- and genetic mapping stood nearly a decade behind Dro- ary 6, 1934. Emerson’s “Historical summary of coopera- sophila. The 10 linkage groups in corn were not all clearly tion among maize geneticists” (RF exhibit A) described identified and the mapping work in each group was still how the maize cooperation began 15 years previously very rough, as illustrated by the “rainbow maps” drawn by in a small way among his former students. Soon other Beadle and Emerson in April 1929 (Figure 4) (Emerson investigators were asked to be included. He documented 1929). interactions among these researchers with a “mimeo- Within the year, however, Barbara McClintock’s iden- graphed summary of linkage in maize, 1929 [sic]” (RF tification of the morphology of the corn chromosomes exhibit D); this exhibit was actually Emerson’s “second (McClintock 1929) and her unpublished research on folder of mimeographed information issued sometime A.5 Perspectives 1791 Figure 4.—Linkage group 9 and Rainbow map as of April 12, 1929 (after Emerson 1929; excerpted from E. G. Anderson’s annotated copy in MNL archives; reprinted in MNL, Vol. 53, pp. 118–119, 1979). after the first one” (mentioned in Emerson 1940). His attack on certain important genetic problems now “mimeographed summary” (RF exhibit D) included all awaiting just such tools as accurate linkage maps afford” of the linkage data compiled and sent to maize geneticists (Emerson 1929, p. 117). on April 17, 1930, and July 26, 1930 (Emerson 1930a,b). Although Barbara McClintock’s name appears amid Emerson’s first (our emphasis) mimeographed letter, Emerson’s list of cooperators, we have no documenta- dated April 12, 1929 (Emerson 1929), “considered News tion that she attended the meeting and it would not Letter 1” by Emerson himself (see Emerson 1940), was have been appropriate in that era for a single woman distributed to maize geneticists shortly after the “corn- to attend a gathering in a man’s hotel room. The cooper- fab” held in Emerson’s hotel room at the time of the ators who did attend, however, were most familiar with AAAS Christmas meetings in New York City in 1928. It McClintock’s work (see Kass 2003) and would have included a long folder of linkage information and the recommended her for this endeavor. Following the New names of researchers assigned each linkage group (see York meeting (December 1928), George Beadle acted as Table 1 based on the original). Emerson (April 12, secretary of the group (Beadle 1929a,b, 1930; Emerson 1929) carefully explained, “To those not at the New 1931). Beadle requested from maize cooperators the York Meeting . . . this assignment [of linkage groups] summaries of linkage data, which Emerson, in coopera- was . . . made in accordance with the expressed interests tion with Beadle and Fraser, would send to cooperators of those assuming the responsibilities entailed. It was far in the spring and summer of 1930. Beadle left Cornell from our purpose to preempt groups for ourselves and in late 1930 for Caltech as a National Research Council thereby warn off other workers. Our purpose rather was Fellow (Plant Breeding Records, CU) (Berg and Singer to make sure that each known group would be given 2003), but continued to receive unpublished linkage data immediate and adequate attention to the end that the from cooperators (Emerson 1931), until Marcus Rhoades not very exciting job of chromosome mapping may go subsequently succeeded him as secretary (Rhoades 1932a). forward with some dispatch, thereby making possible an In his review of “The Early Years of Maize Genetics,” A.6 1792 L. B. Kass, C. Bonneuil and E. H. Coe TABLE 1 To whom linkage groups were parceled out at New York, at the “Cornfab” held in R. A. Emerson’s hotel room in December 1928 Linkage group Recipient C-Wx Eyster (Bucknell University); Beadle (Cornell University) R-G Lindstrom, Jenkins, Wentz (Iowa State University) Su-Tu Emerson (Cornell University) B-Lg Stadler (University of Missouri); McClintock (Cornell University) Y-Pl Hill (Cornell University) P-Br Emerson (Cornell University) Ra-Gl1 Brewbaker (University of Minnesota); Jorgenson (Ohio University); Li (Cornell University) D1-Pg2 Not assigned A-Ts4 Brink (University of Wisconsin); Li (Cornell University) Based on Emerson (1929). Rhoades (1984) recalled the New York City “cornfab,” assume primary responsibility for the group assigned which was his first with the maize cooperators. Rhoades (Table 2) (see also Coe 2001). had arrived at Cornell in the fall of 1928 from the By this time McClintock had left Cornell but her pio- University of Michigan, where he had studied with neering contributions to maize cytogenetics had been Emerson’s former student E. G. Anderson. Anderson both recognized and rewarded. She was awarded a Na- was soon recruited by Morgan for his newly established tional Research Council Fellowship (1931–1933) and, Biology Division at Caltech. Rhoades then spent the after spending time with L. J. Stadler at the University 1929–1930 academic year there with Anderson (CU) of Missouri, had joined Anderson’s group at Caltech, (Anderson and Rhoades 1931; Birchler et al. 2003). where she resumed cooperating with Beadle and Burn- It seems clear, however, that the 1928 AAAS “cornfab” ham. They returned to Cornell to attend the ICG in was not Emerson’s first. the summer of 1932, where Emerson (1932) recognized their contributions to maize cytogenetics. Following the Congress, Rhoades’ first letter to maize ESTABLISHING AND FUNDING THE MAIZE cooperators made clear that “anyone may begin or con- GENETICS COOPERATION AT CORNELL tinue to work with any group whether or not it has been Establishment of the Maize Genetics Cooperation: assigned to him.” It was expected that when “two or Emerson also submitted to the Rockefeller Foundation more are interested in the same group, they will work a copy of Rhoades’ first letter to corn geneticists dated in close cooperation!” Rhoades then distributed a call October 5, 1932 (RF exhibit C; Rhoades 1932a), which for stocks, wants, and news items, on December 12, was retroactively numbered “Vol. 2,” in the Cornell Plant 1932 (Rhoades 1932b), and the third Corn News Letter Breeding Department’s bound volumes of the MNL followed on January 23, 1933 (Rhoades 1933; RF ex- [MNL, Vols. 2–14, 1932–1940, and MNL, Vols. 15–21, hibit C in part). These two letters are bound together 1941–1947; Plant Breeding Department Archives (PB), at Cornell (MNL, Vols. 2–14, 1932–1940, PB) and the Cornell University, Ithaca, NY]. Therein, Rhoades sum- latter is numbered “Vol. 3.” marized the resolutions discussed and favorably acted Funding the Maize Genetics Cooperation: Emerson’s upon by a committee of maize-genetics workers at the “historical summary” (RF exhibit A) additionally re- Ithaca meeting held on August 26, 1932, in connection vealed that his committee was also responsible for devis- with the International Genetics Congress. In addition to ing a way to “carry out the work which the Cornell maize discussing the numbering and naming of gene symbols, geneticists were asked to continue and to enlarge.” His linkage groups, and chromosomes, the group agreed committee did not find a way to provide funds, but it that Cornell should be the “clearing house” where the led to an alternative opportunity. The committee on records would be kept and that a repository should be agronomy appointed by the Division of Biology and formed for storing and disseminating the new informa- Agriculture of the NRC, a unit of the National Academy tion. Emerson, chair of the committee to oversee their of Sciences, unanimously recommended a grant-in-aid resolutions, along with R. Alexander Brink, Donald F. of $1000/year for 5 years for an information and supply Jones, Paul C. Mangelsdorf, and Lewis J. Stadler, had service for maize work to be headed by R. A. Emerson chosen Rhoades (1) to act as custodian of the seed of the Plant Breeding Department of Cornell University, stocks, (2) to furnish a list of stocks received, and (3) for the purpose of maintaining the service for “one of to distribute stocks to workers. They also reallocated the most important crops and . . . for extending our the 10 maize linkage groups to individuals who would knowledge in the field of genetics and cytogenetics” A.7 Perspectives 1793 TABLE 2 cation had been denied, Emerson applied to the Rocke- Reassigned linkage groups feller Foundation for funding and submitted Rhoades’ most recent “mimeographed letter to maize geneticists,” Linkage group Recipient dated January 25, 1934 (RF exhibit J; MNL Vol. 4, PB). By this time, among the 53 maize geneticists engaged Group 1, P-br Emerson in cooperative work on genetic mapping, it appears Group 2, B-lg Beadle Group 3, a1-Rg Brink that not fewer than 30 were Emerson’s collaborators at Group 4, su-Tu Jones Cornell, had been graduate students there, or had done Group 5, pr-v2 Burnham some postdoctoral work in his department. Emerson Group 6, Y-Pl Stadler identified 24 cooperators as “most actively engaged in Group 7, gl1-ra Jenkins genetic studies”; 16 had been graduate students and 2 Group 8, j Sprague had been postdoctoral fellows at Cornell (RF exhibit Group 9, c-wx Eyster E). He submitted the exhibits (RF exhibits A–J), which Group 10, R-g1 Lindstrom we have described here, and also explained that in the Maize linkage groups 1–10 were reassigned to individuals spring of 1933, parts of a manuscript of “A Summary by the committee of maize researchers convened at the ICG of Linkage in Maize” then in the course of preparation on August 26, 1932 (after Rhoades 1932a). Researchers listed are from Rhoades’ letter of October 5, 1932. by Fraser, Beadle, and himself (RF exhibit F) “together with work sheets had been sent to those to whom particu- lar linkage groups had been assigned.” The draft manu- (RF exhibit B). The NRC committee supported their script was, of course, the notable “A Summary of Linkage recommendation with six exhibits (cited as exhibits I– Studies in Maize” that would be published by Emerson, VI), which Emerson had submitted to document his Beadle, and Fraser in 1935. accomplishments to date. These exhibits were not in On March 16, 1934, the Rockefeller Foundation ap- the files at RF but we did locate two exhibits identified propriated $5000 for the New York State College of by Roman numerals: exhibit IV, Rhoades’ letter dated Agriculture at Cornell University for the “support of December 12, 1932 (Rhoades 1932b), and exhibit V, collecting and disseminating maize stocks and informa- dated January 23, 1933 (Rhoades 1933); we found these tion relating thereto” directed by Professor R. A. Emer- numbered exhibits in archived files of the Maize Coop son. Within the week, Emerson (1934) asked cooperators (see also Emerson 1940, where maize communications if they were willing to allow him to use their unpublished are identified by roman numerals). The committee, com- linkage data in “the much heralded and too long de- posed of M. Francis Morgan, Ralph J. Garber, and Richard layed” general linkage summary to be published from Bradfield (chairperson), emphasized that “maize occupies Cornell (NARA). Students of maize genetics responded about the same relative position among plants that the without reservations, fostered by Emerson’s cooperative fruit fly D. melanogaster does among insects” (RF exhibit and enthusiastic, yet trustworthy, nature. Emerson soon B). Surprisingly, their recommendation was not accepted after announced the Rockefeller award in a letter to by the Council. cooperators on September 13, 1934 (MNL Vol. 7, 1934, On December 26, 1933, the secretary of the NRC PB). At that time, 60 genetics researchers were receiving committee on grants-in-aid notified Emerson that after the News Letter. careful study of the application they had decided against By April 1934, McClintock returned to Cornell where making the grant of funds. Emerson received their letter she completed her year-long Guggenheim Fellowship upon returning from the Boston AAAS meetings, where but worried about finding a job (Kass 2003). Emerson both maize and Drosophila geneticists had suggested recognized her abilities toward his MGC enterprise and “standardizing nomenclature and symbolization for requested a separate grant-in-aid to hire her as his re- maize” (RF exhibit H). While there, Emerson had dis- search assistant (RF; CU; Kass 2003) for continued re- cussed with Frank Blair Hanson (Assistant Director, Nat- search on maize cytogenetics. With Emerson’s encour- ural Sciences, Rockefeller Foundation) an alternative agement, his students took advantage of her presence plan for applying for funds to the Rockefeller Founda- to learn new techniques and to receive her cooperative tion should the NRC grant not be approved (Hanson’s guidance. Within the year, Emerson et al. (1935) recog- diary, RF). Four months previously (September 1933) nized McClintock’s, and other maize cooperator’s, con- RF officers Warren Weaver (Director, Natural Sciences) tributions toward their maize linkage studies. Their link- and Hanson, while visiting Cornell on other matters, age summary reported that, using trisomic ratios, had been apprised of Emerson’s “information and sup- McClintock identified 8 linkage groups with chromo- ply service to corn geneticists” and his need for funds; somes 2, 3, 5, 6, 7, 8, 9, and 10. In 1935, Rhoades and but at that time Emerson was confident that the NRC McClintock reported that, by using trisomic methods, would support the work (Weaver’s diary, RF; Emerson 6 of the 10 linkage groups had been associated with to Stadler, November 8, 1933, CU). chromosomes: 2 [B-lg], initially incorrectly assigned to Within a month of learning that the NRC grant appli- 4, 3[a1-lg], 5[pr-v2], 6 [Y-Pl], 7[gl1-ra], and 10 [r-g]; and A.8 1794 L. B. Kass, C. Bonneuil and E. H. Coe that other methods (i.e., reciprocal translocations) gave a definite check on previous trisomic determinations for linkage groups 1, 4 (su-Tu), and 9 (c-wx). The early MNLs (1929–1932, reprinted in MNL, Vols. 52–57, 71, and 72) demonstrate McClintock’s and other coopera- tors’ contributions to their maize linkage studies. Continued cooperation throughout the country and the world: The work of maize cooperators stimulated interests in cytogenetics. By 1935 translocations were used to construct many tester lines that contained both phenotypic characters and a translocation. About one- third of the three-point and four-point tests reported in the linkage monograph (Emerson et al. 1935) involved a translocation as a marker. Such translocation-associ- ated three-point tests were extremely valuable, since they allowed confirmation of gene associations with specific chromosomes and gave the order of genes and of cytological locations with translocation breakage points (McClintock 1931; Rhoades 1931). In addi- tion, Creighton (1934) used pachytene stage chromo- somes to continue deletion mapping studies. Early on, Emerson fostered cooperation among re- searchers throughout the world. He encouraged both domestic and foreign students to join his research team at Cornell (Figures 3 and 4) and published their find- ings in the Cooperation’s News Letter. Soon, this news circular, which united the maize genetics group, was not limited to offers and demands for strains but also disseminated unpublished results among the research- ers. The rule was that any data appearing there could not be cited in publications without the direct consent of the contributor. Maize researchers from around the world—Austria, USSR, Yugoslavia, China, South Africa, Brazil, and Mexico—were honored to share their un- published results, as we found in MNL reports through Figure 5.—Cover of Maize Genetics Cooperation News Let- 1934. ter 19, February 15, 1945. The disclaimer was added to theNews Letter cover for the first time in 1945. The first numbered Maize Genetics Cooperation News Letters: The first set of bound News Letters, which we located in the Department of Plant Breeding at Cor- struct the historical events leading to the establishment nell (MNL, Vols. 2–14, 1932–1940), was numbered by of both the MGC and the MNL and to update and hand in pencil, beginning with Rhoades’ letter of Octo- expand the MNL files (Coe and Kass 2005). The Plant ber 5, 1932, labeled “Vol. 2.” This led us to believe that Breeding Department also has a second set of bound Rhoades’ letter was not Maize News Letter 1. These News Letters with similar hand numbering (MNL, Vols. News Letters appear to have been bound and numbered 15–21, 1941–1947); both sets are currently in the cus- retroactively under the guidance of Emerson, who was tody of Professor Margaret E. Smith on loan to L. Kass). the secretary for MNL, Vol. 14, 1940. The “Historical Professor William B. Provine’s reprint collection in- Notes on Maize Cooperation,” listed on p. 56, of MNL, cludes a set of unnumbered and unbound News Letters Vol. 14, although unsigned, were probably prepared by that belonged to Lester Sharp. Sharp’s unnumbered Emerson, who was secretary for that News Letter. Those collection spans the years 1933–1938 and includes im- notes clearly state that the mimeographed letter of April portant annotations to linkage in maize. Anderson’s 12, 1929, is “considered News Letter 1.” Coe (1976, and Stadler’s unnumbered collections span 1929–1939 1978) used the “Historical Notes” as a guide to compile and are also annotated. The first covered and hand- an archival list of materials of the MNL and related numbered News Letter that we found in Cornell’s Col- cooperation. While conducting research on the history lege of Agriculture Mann Library is “Maize Genetics of maize linkage studies, Kass and Bonneuil (2004) Cooperation News Letter 13, April 15, 1939.” Thereaf- recently found some of the missing (starred) items on ter, the News Letter covers are professionally printed Coe’s list. This new information permitted us to recon- with the title, date, and place of publication—i.e., De- A.9 Perspectives 1795 partment of Plant Breeding, Cornell University. In the TABLE 3 reserve copies transferred from Indiana to Missouri in Transitions of the Maize Genetics 1974, mimeo copies without covers were on file before Cooperation responsibilities 1940, followed by printed-cover copies beginning with Vol. 14. In 1943, Emerson consulted 13 of his most Years News Letter Stocks Database trusted maize cooperators about his concern that some MNL reports had been quoted without permission 1929–1953 Cornell Cornell NA1953–1955 Cornell Illinois NA (Emerson to Cooperators, November 22, 1943, ap- 1956–1957 Illinois Illinois NA pended to MNL, Vol. 17, 1943, PB). A disclaimer was 1958–1974 Indiana Illinois NA subsequently added to the News Letter cover in 1945 1975–1991 Missouri Illinois NA (Figure 5), and since that time the published covers 1991–2002 Missouri Illinois Missouri have not changed with the exception of venue and the 2003– Missouri Illinois Iowa State and Missouri contraction to “Newsletter” on the cover beginning in 1990. from 1953 to 1955, with subsidies from seed companies like DeKalb Agricultural Association; Green Giant; North- CHANGES AND TRANSITIONS IN MAIZE rup, King; and Pioneer Hi-Bred Corn (MNL 28: 1, 1954). GENETICS COOPERATION In 1955, oversight of the MNL moved from Cornell to Emerson officially retired in 1941, and thereafter the Illinois under Marcus Rhoades as secretary (MNL, Vol. MNL was edited by his colleagues, students, and occa- 30, pp. 1–3, 1956) and it accompanied him to Indiana sionally by Emerson himself. He remained active in re- in 1958 (Table 3). At Illinois funding for the MNL was search until his death on December 8, 1947 (Bussell obtained from seed companies and a grant from NSF. et al. 1948). Emerson’s colleagues, former students, and The MNL continued to be edited by Rhoades, aided by friends contributed to a memorial fund in his name Ellen Dempsey (his research associate and former stu- (MNL, Vol. 27, 1953). The funds were applied toward dent), as previously, and prepared and distributed at Indi- the purchase of a lighted exhibit case placed in the hall ana through 1974. That year the MNL transferred to the of the Plant Breeding Department at Cornell (MNL, University of Missouri, under Edward Coe as secretary, Vol. 29, 1955). Part of the exhibit case was used to until 2000, when Mary Polacco and Jim Birchler became display continuously some of Emerson’s own work. This cosecretaries. The News Letter (now “Newsletter”) con- case was on the first floor of the Plant Science Building tinues to be compiled, edited, printed, and distributed at Cornell until the department moved to Emerson Hall, at Missouri and is available online at http://www.maize named for R. A. Emerson, in 1968 (Williams 1968). gdb.org/mnl.php for previously printed issues or at One of the authors (L. B. Kass) recalls assiduously ex- http://www.agron.missouri.edu/mnl/ for issues that are ploring this case in the lobby of Emerson Hall when in process. Support for its distribution is from an endow- she was a graduate student at Cornell in the 1970s. ment fund established from individual and corporate The case is no longer maintained and its contents and contributions. whereabouts are not known at this time. Annual Maize Genetics Conferences were initiated in The Rockefeller Foundation supported the MNL and 1959, following a proposal from John R. Laughnan at Stock Center at Cornell through 1953, when funding the University of Illinois. The conferences are organized was withdrawn (MNL, Vol. 27, 1953). Rhoades recog- and run by a Steering Committee. The 2004 meeting nized and confirmed that by the early 1950s scientists was held in Mexico City. Information about past and at Cornell were ready to forego the Stock Center and future conferences is provided at http://www.maizegdb. News Letter functions when RF withdrew funding, and org/cooperators.php. he arranged to move them to Illinois (see MNL, Vol. The Maize Genome Database (MaizeGDB) was begun 27, pp. 1–2, 1953; Table 3). In 1953, responsibility for in 1991 as an extended medium for communication and the MGC-Stock Center collection moved from Cornell for access to data, established by the U.S. Department of to Illinois, where it was again undertaken by Marcus Agriculture-Agricultural Research Service at Missouri Rhoades, joined by Earl Patterson (MNL, Vol. 28, pp. (USDA-ARS) under the direction of Ed Coe, joined by 2–10, 1954). Support was provided by the National Sci- Mary Polacco. Content of the database, including gene ence Foundation (NSF) until 1981, following which the lists, maps, bibliography, and cooperator’s addresses, U.S. Department of Agriculture supported the program. initially was drawn directly from the files and compila- The Stock Center is now a permanent USDA-Agricultural tions of the MNL, supplemented by entries of new data. Research Service program under the direction of Marty In 2003, the MaizeGDB became a joint endeavor, sup- Sachs. Its history, catalogs, and ordering procedures are ported by USDA-ARS, between Missouri (Mary Polacco) at http://www.aces.uiuc.edu/maize-coop/. and Iowa State University (Volker Brendel, Trent Seig- After the Rockefeller Foundation withdrew support fried, Darwin Campbell, and Carolyn Lawrence). Cura- of the maize cooperation, Cornell funded the MNL tion of data content is conducted at the two locations, A.10 1796 L. B. Kass, C. Bonneuil and E. H. Coe and the database is served from Iowa State at http:// Coe, E. H., Jr., 1978 News letter files. Maize Genet. Coop. News Lett. 52: 146. www.maizegdb.org/. Coe, E. H., Jr., 2001 The origins of maize genetics. Nat. Rev. Genet. In 2000, a Maize Genetics Executive Committee was 2: 898–905. elected whose mission is “to identify both the needs and Coe, E. H., and L. B. Kass, 2005 Maize Genetics Cooperation News Letter files: expanded chronological list of materials and related the opportunities for maize genetics, and to communi- cooperation. Maize Genet. Coop. News Lett. 79: (in press). cate this information to the broadest possible life sci- Cohen, J., 1995 Conduct in science. The culture of credit. Science ence community. This community includes scientists, 268: 1706–1711. Creighton, H. B., 1934 Three cases of deficiency in chromosome funding sources for scientists, and the end users for the 9 of Zea mays. Proc. Natl. Acad. Sci. USA 20: 111–115. accomplishments of maize genetics, from farmers to Crow, J. F., 1992 Sixty years ago: the 1932 International Congress consumers.” Information about the Committee is given of Genetics. Genetics 131: 761–768. Edgar, B., 1975 Worm Breeder’s Gazette, Vol. 1, pp. 1–22. Santa Cruz, at http://www.maizegdb.org/mgec.php. CA. This perspective was developed from a presentation given at the Emerson, R. A., 1923 To students of corn genetics, March 7, 1923; workshop, “The Mapping Cultures of 20th Century Genetics,” at The reprinted in Maize Genet. Coop. News Lett. 52: 47–149 (1978). Emerson, R. A., 1929 To students of maize genetics, April 12, 1929; Max Planck Institute for the History of Science, Berlin, Germany, in reprinted in Maize Genet. Coop. News Lett. 53: 117–130 (1979). March 2001. We thank R. MacIntyre for sharing bound and numbered Emerson, R. A., 1930a To students of maize genetics, April 17, 1930; copies of Drosophila Information Service, Vols. 1–8, 1934–1937; M. E. reprinted in Maize Genet. Coop. News Lett. 54: 136–139 (1980). Smith for sharing bound and hand-numbered copies of MNL, Vols. Emerson, R. A., 1930b To maize geneticists, July 26, 1930; reprinted 2–14, 1932–1940, and Vols. 15–21, 1941–1947; William Provine for in Maize Genet. Coop. News Lett. 54: 140–145 (1980). sharing Lester Sharp’s unbound and unnumbered copies of MNL, Emerson, R. A., 1931 To corn geneticists, Nov. 18, 1931; reprinted 1933–1938, and for extensive use of his reprint collections; R. P. in Maize Genet. Coop. News Lett. 71: 119 (1997). Murphy for significant insights and encouragement for this project Emerson, R. A., 1932 The present status of maize genetics. Proceed- and for sharing his unpublished manuscript on the history of Cornell’s ings of the Sixth International Congress of Genetics, Brooklyn Botanical Garden, Brooklyn, NY, Vol. 1, pp. 141–152. Plant Breeding Department; archivists at the Rockefeller Archives Emerson, R. A., 1934 To cooperators who have contributed unpub- Center, Sleepy Hollow, New York, with special thanks going to T. lished data for a summary of linkage in maize, March 22, 1934. Rosenberg; U.S. National Archives and Records Administration, Col- U.S. National Archives and Records Administration, College Park, lege Park, Maryland, with special thanks going to J. Schwarz; Division MD. of Rare and Manuscript Collections, Carl A. Kroch Library, Cornell Emerson, R. A., 1940 Historical notes on maize cooperation. Maize University, with special thanks going to E. Engst; librarians at the Genet. Coop. News Lett. 14: 56. Mann Library, especially Tom Clausen; and The L. H. Bailey Hortor- Emerson, R. A., and E. M. East, 1913 Inheritance of quantitative ium Library, especially P. Fraissinet for bringing many valuable refer- characters in maize. Nebraska Agric. Exp. Station. Res. Bull. 2: 1–120. ences to our attention. We are grateful to R. P. Murphy, W. B. Provine, Emerson, R. A., G. W. Beadle and A. C. Fraser, 1935 A summary and R. H. Whalen for reading early drafts of this article. L.B.K. acknowl- of linkage studies in maize. Cornell Univ. Agric. Exp. Sta. Mem. edges the following for support of archival research: National Science 180: 1–83. Foundation (grants SBR9511866 and SBR9710488); American Philo- Fraser, A. C., 1924 Heritable characters of maize. XVII. Intensified sophical Society Library, Mellon Resident Research Fellowship; and the red and purple aleurone color. J. Hered. 15: 119–125. Departments of Plant Biology and Plant Breeding and Genetics, Cornell Hutchison, C. B., 1921 Heritable characters of maize. VII. University, Ithaca, New York, for logistical support. Shrunken endosperm. J. Hered. 12: 76–83. Hutchison, C. B., 1922 The linkage of certain aleurone and endo- sperm factors in maize and their relation to other linkage groups. LITERATURE CITED Cornell Univ. Agric. Exp. Station Mem. 60: 1421–1473. Kass, L. B., 2001 Ethics in science: preparing students for their Anderson, E. G., and M. M. Rhoades, 1931 The distribution of career. Plant Sci. Bull. 47 (2, summer): 42–48. interference in the X-chromosome of Drosophila. Papers of the Kass, L. B., 2003 Records and recollections: a new look at Barbara Michigan Academy of Sciences, Arts and Letters, Vol. 13, pp. McClintock, Nobel-Prize-winning geneticist. Genetics 164: 1251– 227–239. 1260. Beadle, G. W., 1929a Dear Sir, Nov. 23, 1929; reprinted in Maize Kass, L. B., and C. Bonneuil, 2004 Mapping and seeing: Barbara Genet. Coop. News Lett. 72: 129–130 (1998). McClintock and the linking of genetics and cytology in maize Beadle, G. W., 1929b Dear Sir, Dec. 19, 1929; reprinted in Maize genetics, 1928–1935, pp. 91–118 in Classic Genetic Research and Its Genet. Coop. News Lett. 54: 136 (1980). Legacy: The Mapping Cultures of 20th Century Genetics, edited by Beadle, G. W., 1930 Dear Sir, Feb. 5, 1930; reprinted in Maize H.-J. Rheinberger and J.-P. Gaudilliere. Routledge, London. Genet. Coop. News Lett. 54: 136 (1980). Kass, L. B., and R. P. Murphy, 2003 Will the real maize genetics Berg, P., and M. Singer, 2003 George Beadle: An Uncommon Farmer. garden please stand up? Maize Genet. Coop. News Lett. 77: 41–43. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY. McClelland, C. K., 1930 The genetics, breeding and improvement Birchler, J. A., R. K. Dawe and J. F. Doebley, 2003 Marcus of corn. A bibliography covering more than forty years work Rhoades: preferential segregation and meiotic drive. Genetics (1889–1929) in the breeding, improvement, and study of inheri- 164: 835–841. tance in corn. Published by the author, Fayetteville, AR. Bridges, C. B., and M. Demerec, 1934 Dros. Inf. Serv. 1: 1–88. McClintock, B., 1929 Chromosome morphology in Zea mays. Sci- Bonneuil, C., and L. B. Kass, 2001 Mapping and seeing: Barbara ence 69: 629. McClintock and the articulation of genetics and cytology in maize McClintock, B., 1931 The order of the genes C, Sh, and Wx in genetics, 1928–1935, presented at the workshop “The Mapping Zea mays with reference to a cytologically known point in the Cultures of 20th Century Genetics,” The Max Planck Institute chromosome. Proc. Natl. Acad. Sci. USA 17: 485–491. for the History of Science, Berlin. Nelson, O. E., 1993 A notable triumvirate of maize geneticists. Ge- Bussell, F. P., B. S. Monroe and L. F. Randolph, 1948 Rollins netics 135: 937–941. Adams Emerson, May 5, 1873–December 8, 1947, pp. 17–20, 40 Provine, W. B., 1986 Sewall Wright and Evolutionary Biology. University in Necrology of the Faculty, 1947–1948. Cornell University, Ith- of Chicago Press, Chicago. aca, NY; reprinted in part in Maize Genet. Coop. News Lett. 22: Rhoades, M. M., 1931 Linkage values in an interchange complex 1–2 (1948). in Zea. Proc. Natl. Acad. Sci. USA 17: 694–698. Coe, E. H., Jr., 1976 News letter files. Maize Genet. Coop. News Lett. Rhoades, M. M., 1932a To corn geneticists, Oct. 5, 1932; reprinted 50: 2–4. in 1982 in Maize Genet. Coop. News Lett. 56: 173–174. A.11 Perspectives 1797 Rhoades, M. M., 1932b To maize geneticists, Dec. 12, 1932; re- Rhoades, M. M., and B. McClintock, 1935 The cytogenetics of printed in Maize Genet. Coop. News Lett. 57: 192 (1983). maize. Bot. Rev. 1: 292–325. Rhoades, M. M., 1933 To maize geneticists, Jan. 23, 1933; reprinted Wagner, R. P., and J. F. Crow, 2001 The other fly room: J. T. in Maize Genet. Coop. News Lett. 57: 192–200 (1983). Patterson and Texas genetics. Genetics 157: 1–5. Rhoades, M. M., 1984 The early years of maize genetics. Annu. Rev. Williams, J. A., 1968 Bradfield and Emerson Halls. New York State Genet. 18: 1–29. College of Agriculture, Cornell University, Ithaca, NY. A.12 APPENDIX II Introduction to Coe, E.H. and L.B. Kass. 2005. Maize Genetics Cooperation News Letter files: Expanded chronolog- ical list of materials and related cooperation. Maize Genetics Cooperation Newsletter 79 (Oct. 31): 72-76; available online April 2005: http://mnl.maizegdb.org/mnl/79/06CoeKass.htm Reproduced in this Appendix is the MNL report for the expanded chronological list of archival materials related to the Maize Genetics Cooperation News Letters and related cooperation. Based on Emerson’s Historical Notes on Maize Genetics Cooperation (MNL 14:56), an original list was compiled by Ed Coe, former editor of the Maize Genetics Cooperation News Letter, and published in 1976 and 1978. Coe’s original list had some items missing from the historical record and, as recorded in this report, Kass and colleagues found some of the missing items. Using many of the archived materials listed in this updated report, Kass et al. (2005, see Appendix I) were able to present an historical perspective of the origin and founding of the Maize Genetics Cooperation News Letter. The Maize Genetics Cooperation News Letter early volumes reprinted in this two-volume 90th Anniversary book provide documentation for the story told in their historical perspective and in the list provided in the following document. A.13 COLUMBIA, MISSOURI University of Missouri ITHACA, NEW YORK Cornell University Maize Genetics Cooperation News Letter Files: Expanded chronological list of materials and related cooperation — Coe, EH; Kass, LB Based on the “Historical Notes on Maize Genetics Cooperation” (Emerson 1940, MNL 14: 56), Coe compiled an “archival” list of materials of the Maize News Letter and related cooperation (MNL 50:2–4, 1976, MNL 52:146, 1978). While conducting research on the history of maize linkage studies, Kass and Bonneuil (Mapping and seeing: Barbara McClintock and the linking of genetics and cytology in maize genetics, 1928–1935. Pp. 91–118 in H-J Rheinberger and J-P Gaudilliere, eds., Classical Genetic Research and its Legacy: The Mapping Cultures of 20th Century Genetics. London: Routledge, 2004) recently found some of the missing (starred) items on Coe’s lists, and a number of additional documents. We (Kass, Bonneuil, and Coe, in preparation) are currently using these documents to construct a history of the Maize Genetics Cooperation Newsletter in celebration of the 75th anniversary (April 29, 2004) of the MNL. We present here an expanded, current list of archival materials and cooperation and welcome your contributions towards completing the collections. Table 1. PB=Plant Breeding bound volumes, Cornell. MMR=Marcus M Rhoades. LS = Lester Sharp File. RAC = Rockefeller Archives Center. NARA = National Archives and Records Administration. MNL File PB Vols 14:56 MMR LS Reprinted No. No. No. No. Dated Dated Pp. Subject in 3/7/23 6 Emerson Factor Notation. 52:147–149 Two-page letter, ‘You who attended the “cornfab” in my hotel room at the time of the winter science 1a I. 4/12/29 30 Emerson meetings in New York…,’ linkage group commitments, and a folder of shared linkage information with 53:117–130 references. “… considered News letter 1.” [ref. MNL 14:56, and in papers of E. G. Anderson]. 1b 11/23/29 2 Beadle Assembling Linkage Data [Brink Papers, U of WI Archives]. 72:129–130 1c 12/19/29 1 Beadle Summarization of Linkage — Request for Data. 54:136 1d 2/5/30 1 Beadle Summarization of Linkage — Request for Data. 54:136 2a.1 II. 4/17/30 17 Emerson Revised maps [“second folder of mimeo” Exhibit D found at RAC, and in papers of E. G. Anderson]. 54:136–139 2a.2 II. 7/26/30 23 Emerson Linkage data [“second folder of mimeo” Exhibit D found at RAC, and in papers of E. G. Anderson]. 54:140–145 11/18/31 1 Emerson Call for Linkage Data [PB Records, Cornell Archives]; “Records should be sent to Dr. G. W. Beadle” atCaltech. 71:119 Cooperation planned at VI Cong (ref. MNL 14:56) [“Cooperation of maize geneticists planned at … 2b II. 8/26/32 Emerson? congress”; Genetics Congress held at Ithaca in August 1932 — Historical Notes in MNL 14:56]; thisapparently does not refer to a written item, but a report/summary of meeting held on 26 August 1932 is included as part of Rhoades’ letter of 10/5/1932 [Exhibit C RAC]. 2c Vol. 2, Congress Report [“action taken at Genetics Congress. Chromosomes assigned to different individuals.”1932 II. 1 10/5/32 3 Rhoades — MNL 14:56], Stocks appeal [RAC, Exhibit C in part]. 56:173–174 Call for stocks contributions and wants, and for news items “so that we may list your contributions and 2d [3]* II. 12/12/32 1 Rhoades wants in the corn-letter which will come out in the near future”, request for data to include in the linkage 57:192 summary; Exhibit IV cited in 1933 NRC grant, see below. Rhoades, RAC, Wants, Symbols, Stocks, Genelist [“Third Corn News Letter …Long list of known genes of maize,” —3a Vol. 3 III. 2 1/23/33 1/23/33 16 Exhibit C in part MNL 14:56] “(MNL 3)” [“Exhibit V” cited in 1933 NRC grant — see below — and included in Exhibit 57:192-200C, RF grant 1934]. Grant Support [ref MNL 14:56]. Emerson submitted the NRC grant in January of 1933, see MNL 14:56, 2e II. 1/?/1933 correspondence by Emerson about possible grant of money for Maize Cooperation, Jan. 1933. Exhibit V = Rhoades 1/23/1933, cited in NRC grant, 1933 and included with Exhibit C, RF grant, 1934]. NRC grant — Report of the Committee on Agronomy of the Division of Biology and Agriculture NRC to support “A Clearing House for Corn Genetics Materials and Information,” dated March 17, 1933 3/17/33 RAC, Exhibit B (found at RAC); Committee recommended but NRC did not approve grant to Emerson; “The project hasbeen set up and is active (Exhibits II, III, IV & V)”; Note exhibits I–IV are not in the file but Exhibit IV is clearly Rhoades’ call of 12/12/32; and Exhibit V is Rhoades’ 1/23/1933, which we identified from Anderson’s copy (reprinted in MNL 57:192-200)]. “This letter is a call for information to be used in succeeding corn letters. We thought it would be 3b [4] III. 3 11/13/33 2 Rhoades appropriate if the first letter in the fall of each year presented new and pertinent information of value to all maize investigators, such as new linkages, …” Deadline January 15. 4 Vol. 4 IV. 4 12/18/33 12/18/33 7 Rhoades News [“Many news items contributed by cooperators,” — MNL 14:56; “Letter of 12 pages” (sic)]. 12/26/33 NRC application denied (Exhibit A, RAC). 5 Vol. 5 V. 5 1/25/34 1/25/34 12 Rhoades Nomenclature, Stocklist [“Big Inventory of corn,” — MNL 14:56] [Exhibit J, RAC]. 2/6/34 CU, RAC Emerson applies to Rockefeller Foundation for grant to support Maize Genetics Cooperation. 6 Vol. 6 VI. 6 2/21/34 2/21/34 4 Rhoades Nomenclature [“Discussion of nomenclature,” — MNL 14:56]. 3/16/34 RAC $5,000 Rockefeller Grant-in-aid for pure research and a clearing house for corn genetics (RAC). Emerson to about 15 “cooperators who have contributed unpublished data for a summary of linkage in 3/22/34 Emerson maize: … I desire to know whether you are now willing to allow publication from Cornell of your as yet unpublished data which are included in the [mimeographed linkage] summary.” [NARA]. VI. 4/1/34 Rockefeller Grant [“April 1, 1934, RF Grant available,” ref MNL 14:56; grant found at RF, see above]. 7 Vol. 7 VII. 7 9/13/34 9/13/34 11 Rhoades Call, News, Genelist, Mailing list of 39 maize geneticists plus 21 others who asked to receive the newsletter; announcement of RF grant for 5 years, no date identified when grant began. 9/13/34 Russia Reference made to 1930 “Linkage in Maize” (MNL 7:3, 1934; see 7/26/30). 8 Vol. 8 VIIII. 8 11/24/34 11/24/34 18 Rhoades News. 9c [9] 1/21/35 1 Rhoades “… call for lists of new genetic stocks, news items, etc., for another corn letter which will be issuedaround the first of March.” Deadline February 15. Stocks, News, Map [20 numbered pages plus unnumbered 3 pages of methods by Randolph; plus Rhoades note (“The enclosed maps of linkage groups were made from the data which Emerson has assembled for the forthcoming paper on linkages in maize by Emerson, Beadle and Fraser”) and a map 9 Vol. 9 IX. 9 3/6/35 3/6/35 22 Rhoades (“CHROMOSOME MAPS OF MAIZE 1935”)]. [Sharp’s copy has 20 numbered pages plus Rhoades’ note following the last numbered page (p. 20) but is missing the linkage map; Anderson’s copy is like PB vol. 9; PB vol. 9 includes 25 pages (20+2+3), of which the last 3 pages are Emerson’s letter of November 30, 1935; see below]. 10b 9/17/35 1 Emerson Disease resistance test cooperation requested [half-sheet; not in PB volume]. Call for news items; summary of linkage in maize off the press; cooperative disease resistance tests; collective short publications on linkage proposed [Emerson signs as secretary “pro tem”; Exhibit “B” at 10c [9] 11/30/35 11/30/35 3 Emerson top of page in green ink (and crossed out) in Emerson’s handwriting (no department number); used to document Emerson’s RF grant report — in pencil is “Put after vol 9 before Vol 10”; Sharp’s copy has A.14 dept. no. 757 at top left but no Exhibit letter at the top of Sharp’s copy]. 10 Vol. 10 X. 3/4/36 3/4/36 22 Emerson News, Data, Stocks, Inbred tests. 11c [11] 11/21/36 1 Langham Call, deadline January 15. 11d [11] 1/5/37 1 Langham Call, deadline January 15. 11 Vol. 11 XI. 3/23/37 3/23/37 26 Langham News, Stocks, Inbred tests. 12c [12] 11/17/37 2 Langham Call, deadline January 15; encouragement of collective short proposals on linkage. 12d [12] 1/22/38 1 Langham Call, deadline advanced to February 15, 1939. News, Stocks, Symbol Index for 1/23/33-3/6/38; Maps by Langham, hand-drawn (A “showing the loci of those genes whose position can be determined with reasonable certainty”; B “showing the 12 Vol. 12 XII. 3/6/38 3/6/38 40 Langham approximate loci of many genes. (Working map. More 3-point tests needed …” [at end of PB volume and in Anderson copy; Sharp’s copy, p. 38 is last page — chromosome linkage maps are missing; Sharp’s last un-numbered copy is dated March 6, 1938]. 13c [13] 1/21/39 1 Langham Call. News, Stocks, Bibliography, Mailing list of 77 persons, 20 outside of the US. Mann Library numbered copies begin with no. 13 [April 15, 1939]; the first bound Plant Breeding volume ends with volume 14, March 5, 1940; The second bound Plant Breeding volume ends with volume 21, March 1, 1947 [“MNL, 13 Vol. 13 XIII. 4/15/39 22 Langham Vols. 2–14, 1932–1940,” & “MNL Vols. 15–21, 1941–1947” (PB)] There are no covers included in the PB bound volumes, only blue pieces of paper separating volumes. — LBK checked the bound volumes at Mann Library; manila folder cover hand written title and number 13 on cover. Anderson copies through this date are unnumbered. 14c [14] 10/31/39 1 Lebedeff Call for 1940 MNL; deadline January 15. 14d Vol. 14 XIV. 1/8/40 1 Emerson Call reminder, half sheet [Not in PB bound volumes]. News, Bibl, Stocks (by Lebedeff), Historical Notes on Maize Genetics Cooperation I–XIV on page 56 14 [14] 3/5/40 56+(3) Emerson likely by Emerson [last 3 pages in PB volume 14 are letter of 2/5/41 and “An Appreciation” of Emerson,see below] [Mann Library Copy, L.J. Stadler copy, and E.G. Anderson copy have only the 56 pgs]. Professionally printed, numbered covers begin with vol. 14. 15c [15] 1/21/41 1 Fraser Call for 1941 MNL; deadline March 1. Letter, Emerson’s retirement and reunion of maize genetics workers: “As you may know Dr. Emerson reaches retirement age this coming June … this coming summer is an appropriate time to hold a reunion of his former students and coworkers in corn genetics. Preliminary arrangements are now being made for 2/5/41 1 Randolph, Fraser such a reunion to be held at Ithaca in late August or early September, either just before or just after the summer meeting of the Genetics Society at Cold Spring Harbor.” List of 30 names to whom this invitation is sent appended below and those (11) who have already indicated they would attend are starred. News, Editorial Policy of GENETICS (Rhoades), Stocks, chromosome assignments, Bibliography 15 Vol. 15 4/1/41 (2)+56 Fraser [Mann Library copy, Anderson copy, and Stadler copy have “An appreciation” of 2 pgs. preceding pg. 1 within the manila cover and affixed with brass round-headed paper fasteners; see above, vol. 14]. 16c [16] 12/10/41 1 Emerson Call; deadline January 15. 16 Vol. 16 2/10/42 i+59 Emerson [Plus Table of Contents] note in memory of Fraser by Emerson; Reports, Stocks (by Einset, Welch),Bibliography (by Emerson). 17c [17] 12/10/42 1 Emerson Call; deadline January 31. 17 Vol 17, 2/15/43 51+(1) Emerson Reports, Stocks, Bibliography [plus 1 pg. 11/22/43 Emerson to 11 cooperators-see below][Only the year1943 is listed on PB copy, Vol. number not hand written in this or subsequent bound PB volumes]. LBK found in PB copy at end of vol. 17, 1943. “This is being sent to” [13 cooperators]. Emerson upset [17] 11/22/43 1 Emerson that News Letter was quoted without permission, “Should we send the newsletter only to workers in maize genetics”. [1943] Assumed Call for 1944, no copy found. 18 Vol. 18 1/31/44 i+32 Emerson [Plus Table of Contents] Reports, Stocks, Bibliography (by A.M. Brown). [1944] Assumed Call for 1945, no copy found. 19 Vol. 19 2/15/45 i+50 Cushing Reports, Stocks (Cushing, Morris), Bibliography [disclaimer added to cover: “The data presented hereare not to be used in publications without the consent of the authors”]. [1945] Assumed Call for 1946, no copy found. Reports, Stocks (Cushing, Morris), Bibliography (by Smith) [pg 2 has an announcement by Emerson, “Arrangements have been made to continue the Maize Genetics Cooperation at Cornell University for a 20 Vol. 20 4/15/46 i+35 Cushing period of not less than three years. Professor R. L. Cushing, who has been responsible for the work done during the past few years, will help initiate Prof. H. H. Smith who will have charge of the work in the immediate future…. R. A. Emerson.”]. [disclaimer is emphasized by addition of a box border]. 21c [21] 12/26/46 1 Smith Call for 1947 MNL; deadline February 15. 21 Vol. 21 3/1/47 i+59 Smith [Plus Table of Contents]. Reports, Bibliography [Last PB bound volume, volume 21, March 1,1947][[disclaimer is further emphasized by a double box border]. 12/8/47 Death of Emerson, Dec. 8, 1947; end of PB bound Maize Newsletters is 1947. 22c 12/17/47 1 Smith Call for 1948 MNL; deadline February 15. 22 3/8/48 i+72 Smith Note in memory of Emerson by L. F. Randolph, B.S Monroe, & F. P. Bussell, Reports, Stocks (byWright), Bibliography (by Wright). 23c 12/28/48 1 Smith Call for MNL 23, 1949; deadline February 15. 23 3/10/49 i+78 Smith Note in memory of Lindstrom by J. W. Gowen; Reports; Stocks (by Wright); Bibliography (by Wright). [1949] Assumed Call for 1950, no copy found. 24 3/17/50 i+81 Smith Reports, Stocks (by Craigmiles), Bibliography. [1950] Assumed Call for 1951, no copy found. 25 3/17/51 i+68 Smith Reports, Historical, Author index vol. 9–24, Stocks (by Craigmiles), Bibliography (by Craigmiles). 26c 1/2/52 1 Smith Call for MNL 26, 1952; deadline February 15. 26 3/17/52 i+76 Smith Report on meeting to discuss Support for the Coop at AIBS Meetings in Minnesota September 12, 1951(Smith); Reports, Stocks (by Craigmiles), Bibliography (by Woodward, Craigmiles). 27b 9/26/52 4 Rhoades Stock Center, Project Outline. 27c 12/30/52 1 Smith Call for MNL 27, 1953; deadline February 15. 27 3/17/53 i+90 Everett Report on meeting to discuss support for the Coop at AIBS Meetings at Cornell September 9, 1952(Laughnan); Reports, Bibliography (by Sherwood). 28c 1/5/54 1 Smith Call for MNL 28; deadline February 15. 28 3/17/54 ii+94 Smith Funds received from hybrid corn companies to support MNL; Reports, Stocks (Patterson), Bibliography(Wright). A.15 29c 12/15/54 2 Smith Call for MNL 29, 1955 with example; deadline February 15. 29 3/17/55 ii+100 Smith Reports, Stocks (Patterson), Bibliography (Wright). 30c 12/7/55 1 Rhoades Call for 1956 MNL (from Illinois), deadline February 15; Transfer of MNL Responsibility. Minutes of 1955 meeting of maize geneticists at AIBS meetings at Michigan State University regarding 30 3/15/56 ii+164 Rhoades transfer of Stocks and the Maize Genetics Cooperation Newsletter, chromosome responsibilities(Patterson); Reports, Stocks (Patterson), Bibliography (Bibl.) [News Letter published in Department of Botany, University of Illinois]. 31c 12/7/56 1 Rhoades Call for 1957 MNL; deadline February 15. 31 3/15/57 ii+173 Rhoades Nomenclature, Reports, Stocks, Bibl. 32c 12/12/57 1 Rhoades Call for 1958 MNL (from Illinois); deadline February 15. 32 3/15/58 ii+156 Rhoades Reports, Stocks, Bibl. [published in Department of Botany, Indiana University][Seed companies fundpublication of MNL; Obituary of Frederick David Richey (1884–1955) by H. K. Hayes]. 33c 12/8/58 1 Rhoades Call for 1959 MNL, deadline February 15 (from Indiana). 33 4/1/59 ii+168 Rhoades Reports, Stocks, Bibl., Mailing list. 34c 12/8/59 1 Rhoades Call for 1960 MNL, deadline February 15. Reports, Stocks, Bibl. [Rhoades incorporates a Foreword to the News Letter and acknowledges Ellen 34 5/1/60 ii+154 Rhoades Dempsey “who has been largely responsible for assembling the News Letter.”][Indiana University and NSF grant (in part) fund publication of MNL]. 35c 12/9/60 1 Rhoades Call for 1961 MNL, deadline February 15. 35 4/15/61 ii+183 Rhoades Reports, Stocks, Bibl. [NSF grant funds publication of MNL]. 36c 12/8/61 1 Rhoades Call for 1962 MNL, deadline February 15. 36 4/15/62 ii+122 Rhoades Reports, Stocks, Bibl. 36i 7/1/62 45 Coe Symbol Index, MNL 12–35 (from Missouri). 37c 12/1/62 1 Rhoades Call for 1963 MNL, deadline February 15. 37 4/15/63 ii+196 Rhoades Reports, Chromosome 1 Data, Stocks, Bibl. 38c 12/6/63 1 Rhoades Call for 1964 MNL, deadline February 15. 38 4/15/64 ii+150 Rhoades Reports, Stocks, Bibl. 39c 12/14/64 1 Rhoades Call for 1965 MNL, deadline February 15. 39 4/15/65 ii+210 Rhoades Reports, Stocks, Bibl. 40c 12/14/65 1 Rhoades Call for 1966 MNL, deadline February 15. 40 4/15/66 ii+205 Rhoades Reports, Map, Stocks, Bibl. 41c 12/21/66 1 Rhoades Call for 1967 MNL, deadline February 15. 41 4/15/67 ii+233 Rhoades Reports, Stocks (Lambert), Bibl. 42c 12/15/67 1 Rhoades Call for 1968 MNL, deadline February 15. 42 4/15/68 iii+208 Rhoades Reports, Stocks, Bibl. 43c 12/15/67 1 Rhoades Call for 1969 MNL, deadline February 15. 43 4/15/69 ii+242 Rhoades Reports, Stocks, Bibl. 44c 12/18/69 1 Rhoades Call for 1970 MNL, deadline February 15. 44i 4/15/70 51 Coe Author and Name Index, MNL 3–43 (from Missouri). 44 4/15/70 ii+232 Rhoades Reports, Stocks, Bibl. 45c 12/18/70 1 Rhoades Call for 1971 MNL, deadline February 15. 45 4/15/71 ii+287 Rhoades Reports, Stocks, Bibl. 46c 12/6/71 1 Rhoades Call for 1972 MNL, deadline February 15. 46 4/15/72 ii+245 Rhoades Reports, Stocks, Bibl. 47c 12/12/72 1 Rhoades Call for 1973 MNL, deadline February 15. 47 4/15/73 ii+277 Rhoades Reports, Nomenclature, Stocks, Mailing list, Bibl. 48c 12/12/73 1 Rhoades Call for 1974 MNL, deadline February 15. 48 5/15/74 ii+244 Rhoades Reports, Stocks, Bibl. 49c 1/13/75 1 Coe Call for MNL 49, deadline February 15 (from Missouri); transfer of responsibility. 49 4/15/75 ii+183 Coe Reports, Stocks, Bibl. [Published at University of Missouri]. 50c 11/1/75 1 Coe Call for MNL 50, 1976, deadline January 1. 50 3/1/76 ii+180 Coe Reports, Stocks, Bibl., Mailing list, Author Index [Chronological list of News Letter Files]. 51c 11/1/76 Coe Call for MNL 51, 1977, deadline January 1. 51 3/1/77 ii+126 Coe Reports, Stocks, Bibl., Author Index (AI), Maps. 52a 4/4/77 2 Coe Request for Cytogenetic Working Map data by October 1. 52b 9/19/77 2 Coe Reminder for Cytogenetic Working Map data. 52c 11/5/77 1 Coe Call for MNL 52, 1978, deadline January 1. 52 3/1/78 ii+178 Coe Reports, Cytogenetic Maps, Stocks, Bibl., Symbol index (SI), AI, News Letter Files list additions, 55Years reprinted (3/7/23). 4/25/78 1 Coe Request for Cytogenetic Working Map data by October 1. 11/1/78 1 Coe Call for 1979 MNL, deadline January 1. 53 3/1/79 ii+166 Coe Reports, Stocks, Bibl., Mailing list, SI for MNL 36–53, AI, 50 Years reprinted (4/12/29). 4/12/79 1 Coe Request for mapping work and new data. 11/9/79 1 Coe Call for 1980 MNL, deadline January 1. 54 3/31/80 ii+163 Coe Reports, Zealand, Stocks, Bibl., Mailing list, SI, AI, 50 Years reprinted (12/19/29, 2/5/30, 4/17/30,7/26/30). 11/5/80 4 Coe Stock Center support from USDA; Questionnaire on MNL features and on Stock Center functions. 11/15/80 1 Coe Call for 1981 MNL, deadline January 1. 55 3/15/81 iii+161 Coe Reports, Zealand, Stocks, Bibl., SI, AI. A.16 11/20/81 1 Coe Call for 1982 MNL, deadline January 1. 3/2/82 1 Coe Plan for meeting on mapping. 56 3/15/82 iv+208 Coe Reports, Zealand, Stocks, Mailing list, Bibl., SI, AI, 50 Years reprinted (10/5/32). 4/22/82 30 Coe Planning with Mapping Coordinators; data compilations. 12/1/82 1 Coe Call for 1983 MNL, deadline January 1. 3/3/83 4 Coe Planning with Mapping Group; data compilations for 1983. 57 3/31/83 iv+236 Coe Reports, Zealand, Genelist & Maps, Stocks, Bibl., Mailing list, SI, AI, 50 Years reprinted (12/12/32,1/23/33). 8/5/83 3 Coe Coordination of mapping, chromosome responsibililties. 10/31/83 1 Coe Request to Mapping Coordinators for summarized reports by January 1. 11/23/83 1 Coe Call for 1984 MNL, deadline January 1. 58 4/30/84 vi+258 Coe Reports, Mapping, Zealand, Stocks, Bibl., Mailing list, SI, AI, Maps. 11/8/84 1 Coe Call for 1985 MNL, deadline January 1. 1/10/85 1 Coe Request to Mapping Coordinators for summarized reports. 59 3/31/85 iv+187 Coe Reports, Mapping, Zealand, Stocks, Mailing list, Bibl., SI, AI, Cytogenetic Data, Maps. 11/15/85 2 Coe Call for MNL 1986, deadline January 1; request to send stocks to Stock Center; information onintegrated mapping. 11/29/85 15 Coe Minutes of National Plant Genetic Resources Board re mapping integration for maize. 1/21/86 1 Coe Request to Mapping Coordinators for summarized reports. 3/12/86 1 Coe Planning with Mapping Group for meeting on mapping. 60 3/31/86 viii+212 Coe Reports, Zealand, Stocks, Mapping, Mailing list, Bibl., SI, AI. 11/15/86 2 Coe Call for 1987 MNL, deadline January 1. 1/13/87 1 Coe Request to Mapping Coordinators for summarized reports. 61 3/31/87 iv+177 Coe Reports, Zealand, Stocks, Mapping, Mailing list, Bibl., SI, AI. 11/15/87 2 Coe Call for 1988 MNL, deadline January 1. 1/20/88 1 Coe Change to require Subscriptions and Endowment. 62 3/31/88 iv+179 Coe Reports, Zealand, Stocks, Mapping, Genelist, Maps, Mailing list, Bibl., SI, AI. 11/21/88 1 Coe Call for 1989 MNL, deadline January 1; Maize Conference news. 63 3/31/89 xi+195 Coe Reports, Zealand, Stocks, Mapping, Mailing list, Bibl., SI, AI, Donors. 11/15/89 1 Coe Call for 1990 MNL, deadline January 1; Maize Conference news. 64 3/31/90 ix+208 Coe Reports, Zealand, Stocks, Genelist, Maps, Mailing list, Bibl., SI, AI, Donors. 11/15/90 1 Coe Call for 1991 MNL, deadline January 1; Maize Conference news. 65 3/1/91 viii+212 Coe Reports, Zealand, Stocks, Genelist, Maps, Mailing list, Bibl., SI, AI, Donors. 66 3/15/92 x+220 Coe Reports, Zealand, Stocks, Genelist, Maps, MaizeDB, Mailing list, Bibl., SI, AI, Donors; Rhoadesmemory by Dempsey. 11/10/92 1 Coe Call for 1993 MNL, deadline January 1; Maize Conference news; Marty Sachs to head Maize GeneticsCooperation — Stock Center. 67 3/15/93 vii+231 Coe Reports, Zealand, Stocks, Genelist, Maps, MaizeDB, Mailing list, Bibl., SI, AI, Donors; MaizeDB reportand access through Gopher; issue dedicated to McClintock, references to essays and memories. 11/1/93 1 Coe Call for 1994 MNL; access available through Gopher, AceDB, WWW, and MaizeDB; Maize Conferencenews; Patterson retires from responsibilities with the Stock Center, Stinard Curator. 68 3/15/94 vii+253 Coe Reports, K-12, Mailing list, Stocks, Zealand, Nomenclature, Genelist, Maps, MaizeDB, Bibl., SI, AI,Donors. 12/14/94 2 Coe Call for 1995 MNL by email; access available through Gopher, AceDB, WWW, and MaizeDB; MaizeConference news. 12/14/94 1 Coe Call for 1995 MNL; access available through Gopher, AceDB, WWW, and MaizeDB; Maize Conferencenews. 69 8/15/95 viii+321 Coe Reports, K-12, Mailing list, Stocks, Nomenclature, MaizeDB, Probe Bank, Genelist, Maps, Zealand,Bibl., SI, AI, Donors. 11/13/95 1 Coe Call for 1996 MNL; Maize Conference news. 70 3/15/96 v+185 Coe Reports, Mailing list, Stocks, MaizeDB, Probe Bank, Genelist, Maps, Zealand, Bibl., SI, AI, Donors. 10/22/96 2 Coe Call for 1997 MNL by email; initiation of Virtual MNL, Verbatim incorporation, and Linkletter. 11/13/96 1 Coe Call for MNL 71 by postcard. 71 4/15/97 iv+126 Coe Reports, K-12, Mailing list, Stocks, MaizeDB, Probe Bank, SI, AI, Donors; 66 Years reprinted(11/18/31). 8/20/97 1 Coe Call for MNL 72, 1998 on web in MaizeDB; Virtual MNL, Verbatim incorporation, and Linkletter. 12/3/97 1 Coe Call for MNL 72, 1998 by postcard. 12/3/97 1 Coe Call for MNL 72, 1998 by email; Maize Conference news. 72 4/15/98 iv+134 Coe Reports, Mailing list, Stocks, MaizeDB, Probe Bank, Maps, SI, AI, Donors, 69 Years reprinted(11/23/29). 11/30/98 1 Coe Call for MNL 73, 1999 by email; Maize Conference news. 73 4/15/99 iv+155 Coe Reports, Mailing list, Stocks, MaizeDB, SI, AI, Donors. 11/29/99 2 Coe Call for 2000 MNL by email; Maize Conference news. 74 4/15/00 x+116 Coe Reports, Mailing list, Stocks, MaizeDB, SI, AI, Donors; Li Jing Xing (C.H. Li) memory by Chase;Patterson memory from Illinois. 11/17/00 1 Birchler, Polacco Call for MNl 75, 2001 by email. 11/17/00 1 Polacco, Birchler Call for MNL 75, 2001 on web in MaizeDB. 11/21/00 1 Coe MNL self-supporting, change in subscription policy; MNL 59 and above in MaizeDB. 75 8/15/01 vii+131 Polacco, Birchler Reports, Mailing list, Stocks, MaizeDB, SI, AI, web sites, Maize Genetics Executive Committee,sequencing report; transfer of responsibility for MNL to Polacco and Birchler. [2001] Polacco, Birchler Call assumed. 76 5/15/02 vi+148 Polacco, Birchler Reports, Mailing list, Stocks, MaizeDB, SI, AI; Nelson memory by Hannah, Burr, Dooner. A.17 11/30/02 1 Polacco, Birchler Call for 2003 MNL by email. 77 7/29/03 iii+183 Polacco, Birchler Reports, Mailing list, Stocks, MaizeDB, SI, AI; recent Donors. 12/8/03 1 Birchler, Polacco Call for 2004 MNL by email. 78 7/26/04 iii+163 Polacco, Birchler Reports, Address List, Stock Center, Community IBM (cIBM) Maps, Recent Maize Publications, SI, AI * numbers in brackets represent the volume with which that communication was bound in the PB set — i.e., Rhoades call of 12/12/32 was bound with Volume 3, 1/23/33. LBK acknowledges the National Science Foundation (grants SBR9511866 and SBR9710488), for support of archival research; the Departments of Plant Biology and Plant Breeding at Cornell University for logistical support; with grateful thanks to Chris Bonneuil, Royse P. Murphy, William B. Provine, and Margaret Smith, for sharing notes and documents in the spirit of maize cooperation; to archivists Thomas Rosenbaum, RAC and Joseph Schwarz, NARA, for permission to use the collections and for supplying information and copies of letters, and to Mary L. Polacco for encouragement and aid in systematizing the information. Please Note: As is the policy with the printed version, notes submitted to the Maize Genetics Cooperation Newsletter may be cited only with consent of the authors. Return to the MNL Volume 79 Index Return to the index of Maize Newsletters Return to the Maize Genome Database Page A.18 APPENDIX III. Contributor’s Biographical Sketches Editors: Dr. Lee B. Kass received her Ph.D. in botany and genetics from Cornell University (1975), and earned a B.S. in biology at The City College of New York (CUNY, 1969). She did postdoctoral research at The University of Cam- bridge (UK) and Vanderbilt University. She has served on the faculties of The University of Cambridge (UK), University of Tennessee (Nashville), Elmira College (New York), The College of the Bahamas (Nassau), Cornell University, and West Virginia University (Morgantown). Kass has authored, edited or co-edited ten books, and authored or co-authored more than 90 book chapters, proceedings papers, and articles in scientific journals. She is a member of the Botanical Society of America, The Bahamas National Trust, and a former member of many bo- tanical organizations. Kass was chair of the Historical Section of the Botanical Society of America for many years. She established the Elmira College Herbarium in 1985, and currently serves on the Science Advisory Committee of the Bahamas National Trust. Among her awards is the Josef Stein Award, for excellence in teaching and schol- arly achievement (1985) and a Fulbright Scholar Award (1996), during which time she and her spouse, Dr. Robert E. Hunt, established the National Herbarium of the Bahamas. She is Visiting Professor at Cornell University, and West Virginia University (Morgantown). Her research focuses on history of botany, and biodiversity and repro- ductive biology of Bahamian plants. Dr. Edward H. Coe Jr. earned a Ph.D. (1954) in botany at the University of Illinois (with John Laughnan) and re- ceived his M.S. degree (1951) in plant genetics (with Charlie Burnham), and a B.S. degree (1949) in agronomy and plant genetics from the University of Minnesota. Following a postdoc with Ernest G. Anderson at Caltech (1954- 1955), Coe joined the Plant Genetics Unit of the U.S. Department of Agriculture-Agricultural Research Service at the University of Missouri, where he is currently Professor Emeritus of Plant Sciences. His research has contrib- uted to an understanding of anthocyanin biosynthesis, gametophyte functions, non-Mendelian inheritance, and extrachromosomal inheritance. He is author of or co-author of over 100 refereed journal articles, and author or co-editor of two books; most well-known is the co-edited Mutants of Maize. Coe is highly appreciated for his 26 years of continuous service as editor of the Maize Genetics Cooperation Newsletter (1974-2000). He played a central role in establishing the Maize Genome Database and in the early planning meetings leading to sequencing of the first plant genome, the maize genome. He is a member of various professional organizations, including the Genet- ics Society of America, the American Genetic Association, and the Crop Science Society of America. In recogni- tion of his “lifetime contributions to the field of genetics,” Coe was awarded the prestigious Thomas Hunt Morgan Award by the Genetics Society of America in 1992. The award was presented to him in recognition of the impor- tance of his basic research, his mentorship of students and postdocs, and his extensive and outstanding service to the maize genetics community. Dr. Coe was described as “the glue that holds the maize community together.” At the 2018, 60th Annual Maize Genetics Conference, held at Palais du Grand Large, Saint-Malo, France, Coe was honored with the newly established R.A. Emerson Award, which recognizes individuals for their extraordinary lifetime achievements in maize genetics. Recipients of this award are leaders in the maize community, who have made seminal contributions to our understanding of maize genetics. Coe’s Emerson Award was presented at the March 2019 Maize Genetics Conference in Saint Louis, along with a short overview of his life and work. In April 2019, the Academy of Science – St. Louis honored Coe with The Peter H. Raven Lifetime Achievement Award, which recognizes a distinguished career of service in science, engineering, or technology. Michael N. Cook is a Librarian whose MLIS degree (1997) and MA degree in philosophy (1994) are from the Uni- versity of South Carolina, with a B.A. degree in English (1990) from Western Carolina University. He is the Head of Collections at Cornell University’s Albert R. Mann Library. His areas of expertise include collection development, digital preservation, copyright, open access, digital repositories, special collections and rare books, and scholarly communication. Michael was the 2007 recipient of the State University of New York (SUNY) Chancellor’s Award for Excellence in Librarianship and also received the 2017 Melanie Gardner Agriculture Network Information Collaborative (AgNIC) Distinguished Service Award. A.19 Dr. Margaret E. Smith received her Ph.D. (1982) in Plant Breeding and Genetics from Cornell University. She subsequently worked as a plant breeder at the Tropical Agricultural Center for Research and Teaching (CATIE) in Costa Rica, and then ran a successful corn breeding program at the International Maize and Wheat Improvement Center (CIMMYT). Smith returned to Cornell in 1987 as an Assistant Professor of Plant Breeding & Genetics to head the corn breeding research project. She is now Professor and also the Associate Director of the Cornell University Agricultural Experiment Station. Her research goal is to enhance an understanding of corn adaptation to marginal environments and develop genetic materials that will improve corn productivity and sustainability in such environments. She assumed responsibility in 2004 as Extension Leader for Plant Breeding and Genetics, focusing on public education about plant breeding, variety testing, and seed issues. Smith is the Project Leader for the New York Seed Improvement Program of Plant Breeding and Genetics. She oversees the Corn Variety Testing program, which aims to evaluate hybrids over a range of environments in New York. She also teaches about ge- netically engineered crop plants (basic public issues education) and agriculture in the developing world. She has trained more than 20 Ph.D. students, and six Masters students. She was the recipient of the Outstanding Faculty Award (2015) from the College of Agriculture and Life Sciences Alumni Association and the College of Agricul- ture and Life Sciences (CALS) 2012 Outstanding Service to CALS award. Judy L. Singer received her BA (1977) in Sociology/Anthropology, from Ithaca College. She began working at Cornell Plant Breeding for Professor and Department Extension Leader William D. Pardee in 1976, as a Secretary, then as an Extension Support Aide, and finally as an Extension Support Specialist. For 25 years she traveled the state of New York for the New York Hybrid Corn Performance Trials testing program participating in all aspects of field testing operations, collecting, compiling, analyzing data, and producing final reports. She later worked with Margaret Smith, and other Plant Breeding faculty members affiliated with the applied Plant Breeding programs. Judy helped Dr. Pardee to organize the 75th Synapsis Club Reunion (1982). She had organized, and saved, most of the files from that event, which later proved invaluable to the publication of the Department’s Centennial His- tory. She co-served as a production coordinator for the print version of the 2007 Centennial History book, and proof read the hard copy and later the e-book. She was also a member of the committee to organize former Plant Breeding Department Chair (1956-1979) R.P. Murphy’s 90th birthday celebration (May 2, 2004). For that event she organized family photographs, helped to coordinate events, and compiled the Memory Book of the event. She proofread for the McClintock Perspectives Companion Volume, edited by Kass. Judy retired from her permanent Cornell appointment in 2009 and was asked to return in a part time Temporary Service Professional position. On 29 November 2017, Judy received the first Chair’s Award for Excellence, for her 33 years of full time service to Plant Breeding & Genetics. She continues to work closely with the Plant Breeding & Genetics designated historian, Dr. Lee B. Kass, to save files of historical significance to the history of one of Cornell’s most notable Departments. Foreword Contributor: Dr. Edward S. Buckler received his Ph.D. (1997) in biological sciences from the University of Missouri-Columbia. He served as research geneticist, U.S. Department of Agriculture - Agricultural Research Service (USDA-ARS), and Adjunct Assistant Professor of Genetics at North Carolina State University, Raleigh, from 1998 to 2003, before starting at the USDA/ARS Robert W. Holley Center for Agriculture and Health, at Cornell’s Institute for Genomic Diversity in 2003. Buckler is a Research Geneticist with the Senior Scientific Research Service, USDA–ARS, and an Adjunct Professor of Plant Breeding & Genetics at Cornell. He is recognized as a leader in the integration of quantitative and statistical genetics with genomic approaches, whose work has deepened our understanding of the control of crop complex traits, and applying those superior genetic variations to crop improvement. Subsidized by the United States Department of Agriculture and National Science Foundation, he has led the largest maize re- search team in the US, achieving more than 200 periodical publications, including Science, Nature, Nature Genet- ics, PNAS, Plant Cell, Nature Review Genetics and Nature Communications. He has had the pleasure of mentoring over 50 postdocs and graduate students. In 2014, Buckler was elected to the U.S. National Academy of Sciences (NAS), Section of Plant, Soil, and Microbial Sciences. He was the recipient of the 2017, NAS Prize in Food and Agricultural Sciences, the first time this prize was awarded. This prize recognizes research by a mid-career scien- A.20 tist at a U.S. institution who has made an extraordinary contribution to agriculture or to the understanding of the biology of a species fundamentally important to agriculture or food production. Manuscript Reviewer: Dr. Mark E. Sorrells received his Ph.D. (1977) in Plant Breeding and Plant Genetics from the University of Wis- consin – Madison. After a short post-doc he joined the faculty at Cornell University in the Department of Plant Breeding & Biometry. Since 1991 Dr. Sorrells has been Professor and served as Chair of the Department of Plant Breeding & Genetics at Cornell University (2006-2014). The primary focus of Dr. Sorrells’ research program is breeding methodology with application to oat, barley and wheat breeding for the Northeastern region of the United States. He has also been involved in several international projects in Africa, South America, and Europe. During his career Dr. Sorrells has actively developed and evaluated new breeding methods and currently he is in- tegrating genomic selection into his breeding program to reduce pre-harvest sprouting, increase disease resistance and improve yield. Dr. Sorrells has published more than 288 papers in peer-reviewed journals. He has been active in teaching and advising students, serving as major advisor to 45 Ph.D. students, 12 M.S. graduate students and minor advisor to 25 students. He is advisor to Cornell’s Synapsis Club, the student-faculty organization founded by H.J. Webber when the Department began in 1907. Sorrells is a Fellow of the Atkinson Center for a Sustainable Future, a Fellow of the Cornell Institute for Food Systems, a Fellow of the Crop Science Society of America, and of the American Association for the Advancement of Science. He is the recipient of the faculty Award for Outstand- ing Career Accomplishments in Applied Research (2012), College of Agriculture and Life Sciences, Cornell Uni- versity; the SUNY Chancellor’s Award for Excellence in Faculty Service (2015); and of the Outstanding Research Award (2016), of the Crop Science Society of America. A.21 FThiguisre 1 3914. 519 S4y5,n Aapprsiils 2 C3,l Suybn gaprosius pC lpuhb.oto is the last one we have that includes Professor R.A. Emerson (middle row, L3erftd t ofr Romigh lte, ftBa).c kO Rf otwh:e L sGev Ceonx ,w OoFm Ceunr tiins, tGhEe Wphilolltios,, SfHou Arl dornic fhr,o VnGt rGouwzm [farno,m M Ale ftB,a eFzlao, rGen Bclaen Nco. , ThETo Bmulalsa r(d4, )W, FEu Cnhga ppell, CT iTningg F, uWn gE t(o6. )M, Mid.d Rle oRsoawli:n FdP M Buosrsreilsl , (K7)D L Beuotnlear O(sp. eSackhenr)e, RA Emerson, JS Niederhauser, WH Burknolder, RL Cushing, HM Mbeutnwgeere, nS F1r9id4r6ic aknsodn 1, P9 4G8r.u (nR, eDpDri Dntoeldan f,r Com Br aMntuornp, hWy T& C Kraaig ll, (E8H)] C raescseerivese.d F rtohneti Rr oPwh:. ED K.so wuditahl, PGl Saenetl yBer, eHeHd iLnogv efa, Fc uThltoym as, WF Mai, FT Fung, R Morris, L Schnell, L Rubin. ss 2011, p. 157; courtesy of Plant Breeding & Genetics and the publisher) (Courtesy Rare and Manuscript Collections, Cornell University Library). Figure 32. 1946. Emerson pollinating celery in greenhouse (Courtesy HM Munger, Department of Plant Breeding files) 157 Maize Genetics Cooperation News Letter volumes 2-14 (1932-1940), and 15-21 (1941-1947), compiled by R.A. Emerson (background), and bound for the former College of Agriculture Library, Cornell University. (Courtesy of Margaret E. Smith, Plant Breeding & Genetics, Cornell University; photo image by Judy Singer)