Plant Biology Masters Projects

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Now showing 1 - 6 of 6
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    Quade, Michael (2021-08)
    The cold hardiness and deacclimation rates of various clones of four V. vinifera grapevine varieties were evaluated by measuring lethal temperatures of dormant buds using low temperature exotherms. This study aimed to elucidate the potential cold hardiness trait differences across clones of each variety. Levels of cold hardiness play an important role in grower choice when considering planting new fields or replacing lost crops in regions subject to low temperatures during the winter. Ultimately, it was shown that there is no significant cold hardiness difference between clones within any of the four sampled varieties. However, a revised experimental design and additional sampling must be done over multiple seasons to gain a better view of any potential clonal variation that may arise. It is likely that the microclimatic environmental differences between vineyard sites was a compounding factor, and as such the effect of clonal variation was challenging to isolate. The results of this study did show a discernable difference in cold hardiness levels and deacclimation rates between the sampled varieties, which is well-documented in other studies in this area. While it is still unknown whether clone has an influence on winter cold hardiness, these results may be important for future vineyard plantings in regions with increased winter temperature fluctuation as a result of ongoing climate change. Additionally, further investigation is warranted into the potential genetic variation between clones within a variety, as this may uncover the basis for other clonal trait variations of interest.
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    Grasso-Monroe, Sage (2021-08)
    National Agriculture Research Systems (NARS) perform a unique context-specific role in agriculture research and development, impacting food security in developing countries. NARS contribute to crop improvement research by generating improved plant varieties adapted to diverse agro-ecological zones and preferences of target populations. They are responsible for addressing the demands for orphan crops economically, culturally, and nutritionally relevant to specific populations in developing countries. The Feed the Future Innovation Lab for Crop Improvement (ILCI) aims to support NARS in developing and implementing Tools, Technologies, and Methodologies (TTMs) that enhance the delivery of genetic gains in crops that advance economic growth, crop resilience, and nutritional development in target populations. The Tata-Cornell Institute for Agriculture and Nutrition (TCI) is part of a multidisciplinary team within ILCI, tasked with researching institutional components that contribute to the capability of NARS to implement innovative TTMs to achieve genetic gain. This paper outlines the methodologies and outcomes of the approach implemented by TCI to establish baseline metrics to assess the capacities of ILCI partner NARS. To develop the metrics, TCI undertook a robust research process, incorporating a systematic literature review, evaluation of existing tools to measure breeding program capacity, consultation with experts, implementation of the Delphi technique, and a pilot with the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) crop improvement programs. The scarcity of institutional capacity literature confirms the need for the framework TCI created. Currently, standardized methodologies to assess crop improvement programs with limited resources to contract experts for program evaluation are inadequate, exposing the potential demand for a low- input assessment tool. The metrics will be implemented through a survey instrument to compare institutional level capacities at the start and end of the ILCI project. An index will be constructed from survey responses to simplify multivariate indicators and enable comparisons over time. The objective is to assess the impact of TTM adoption through the ILCI project on capacity indicators.
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    Mei, Linkai (2021-08)
    This study uses two chloroplast genes (psbA and rbcL) and morphological data collected online and from herbarium specimens to generate phylogenetic trees for 13 species of maple (Acer). Alignment of sequences and phylogenetic analyses were performed and visualized with the programs MUSCLE, RAXML, MrBayes, MESQUITE, and ITOL. ML and Bayesian analyses were used to generate phylogenetic trees, and these were compared with results from a previous study by Li. Results indicate that Acer griseum, Acer caesium, Acer hyrcanum, and Acer platanoides form a monophyletic terminal clade, and this is the most robust result of these analyses. Acer grandidentatum and Acer saccharum are monophyletic in the ML analysis, but unresolved in the Bayesian analyses, which makes sense because Acer grandidentatum is a subspecies of Acer saccharum.
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    Fang, Emily (2021-08)
    Venturia inaequalis (Cooke) G Wint is an ascomycete fungus and the causal agent of apple scab, and economically devastating disease of fresh market apples. The disease is characterized by olive-colored, scabby lesions that develop on leaves and fruit, which leads to reduced yield of marketable fruit (Jones and Aldwinkle, 1990; MacHardy, 1996). A lack of resistance among commercially preferred cultivars has mandates the need for more than 10 fungicide applications per season to manage the disease. Due to a history of sequential resistance development shortly after the introduction of single-site fungicides, apple scab management relies heavily on multi-site fungicides such as mancozeb and captan, which protect trees from a wide range of pathogens from bud break through summer (Agnello et al. 2019; Cox, 2015). Currently, multi-site fungicides are used in rotation with single-site SDHI fungicides to manage apple scab. However, there are concerns about the potential off-target impacts of multi-site fungicides, as well as the environmental impact of excessive application. Due to the negative impacts of commonly used multi-site fungicides such as mancozeb and captan on the environment and human health, some countries have considered restrictions and limitations on the use of mancozeb and captan, making it necessary to reduce the use of multi-site fungicide in management programs. In this study we eavaluate a potential apple scab management program that rotates the biopesticide Serenade Opti (a.i. Bacillus subtilis) with the single-site fungicide Aprovia (a.i. benzovindiflupyr) and compare the disease control to a conventional management program that rotates the multi-site fungicides Manzate Max and Captec (a.i. mancozeb, captan) with the single-site fungicide Aprovia. The programs were tested on two different application schedules (calendar and a schedule determined by the decision support system NEWA), as well as in two different orchard planting styles (vertical axis and modern super spindle) to compare the impact on disease control. Over the course of the study, we found that biopesticides are a potentially viable substitute for multi-site fungicides as a rotational partner for single-site fungicides when paired with decision support systems and modern super spindle plantings. There were no significant differences between management programs using biopesticides and programs using multi-site fungicides in either high or low disease pressure scenarios. Our study supports observations made by Boland (1997), that indicates biological controls are most effective when used in environments less conducive to pathogen development. Overall, this study is a proof-of- concept that demonstrates the feasibility of a management program using biopesticides as a rotational partner with single-site SDHI fungicides, and that the program is comparable to industry standard programs that use multi-site fungicides.
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    Wang, Han (2021-08)
    Melastomataceae is one of the most important plant families in the pantropical areas. Recently, some Melastomataceae fossils were discovered in the Old Crossman Clay Pit locality in Sayreville, New Jersey. The fossils were charcoalified with preserved three-dimensional morphology and excellent anatomical details. Further phylogenetic analyses revealed the fossils belonged to the group of early-diverging Melastomataceae. The location of this fossil taxon in present day northern New Jersey has implications for the paleobiogeography of the family.