Dissertation
BREEDING AND EVALUATION TOOLS FOR PREHARVEST SPROUTING, EMERGENCE, AND ENVIRONMENTAL STABILITY OF FALLING NUMBERS IN BREAD WHEAT
Doctor of Philosophy (PhD), Washington State University
01/2020
Handle:
https://hdl.handle.net/2376/111346
Abstract
Wheat (Triticum spp.) is an economically and nutritionally important crop, providing an average 20% of the daily protein and caloric intake for most of the global population. The soft white winter wheat market class that is largely used for cookies, pastries, and cakes. Success in the export market demands excellent end-use quality and does not tolerate starch damage due to alpha-amylase enzyme activity in the grain. Two independent genetic causes of alpha-amylase accumulation in mature grain are late-maturity alpha-amylase (LMA) due to temperature fluctuations during late grain filling, and preharvest sprouting, the germination of grain on the mother plant when cool, rainy conditions occur before harvest. The wheat industry detects alpha-amylase digestion of starch using the Hagberg-Perten falling number test. It is essential to address this problem to prevent recurrent falling number losses. The objectives of this dissertation were to explore approaches to evaluate the risk of LMA and preharvest sprouting, evaluate susceptibility in existing cultivars, and finally find a good breeding strategy for this problem. Because preharvest sprouting tolerance results mainly from higher grain dormancy, it is important to strike a good balance where there is enough dormancy at maturity to reduce sprouting risk but not so much as to prevent good seedling emergence in fall-planted wheat. We identified the important genetic loci controlling seedling emergence and preharvest sprouting traits in pacific northwest breeding lines and varieties using a genomewide association mapping approach. A total of 90 markers associated with preharvest sprouting traits and 85 markers associated with seedling emergence traits were detected in these studies. Although most of these QTL were not supported across multiple environments, a few large effect QTLs were identified for potential application in the breeding program using marker-assisted selection. A genomewide selection approach was explored for use in making genetic gains for preharvest sprouting, contrasting the prediction accuracy of a basic model with one incorporating a large effect emergence QTL. We found that prediction accuracies were not significantly different between the models, suggesting it is possible to make improvements to preharvest sprouting without undermining seedling emergence, an important yield determinant.
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Details
- Title
- BREEDING AND EVALUATION TOOLS FOR PREHARVEST SPROUTING, EMERGENCE, AND ENVIRONMENTAL STABILITY OF FALLING NUMBERS IN BREAD WHEAT
- Creators
- Stephanie Sjoberg
- Contributors
- Arron H Carter (Advisor)Camille M Steber (Advisor)Kimberly A Garland Campbell (Committee Member)Zhiwu Zhang (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Crop and Soil Sciences, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 246
- Identifiers
- 99900581614101842
- Language
- English
- Resource Type
- Dissertation