Thesis
Molecular mapping of stripe rust resistance and freezing tolerance in winter wheat (Triticum aestivum L.)
Washington State University
Master of Science (MS), Washington State University
2012
Handle:
https://hdl.handle.net/2376/102748
Abstract
Wheat (Triticum aestivum L.) is a staple crop of major economic importance that is challenged with myriad of both biotic and abiotic yield limiting factors resulting in major efforts to overcome these challenges. Genetic mapping is a powerful tool that facilitates the identification of loci controlling traits of interest. Marker assisted selection techniques can utilize data generated from genetic mapping to allow breeders to rapidly provide growers with the most suitable cultivar possible. Our objectives were to identify markers linked to stripe rust (Puccinia striiformis f. sp. tritici) resistance and freezing tolerance in a mapping population of 268 recombinant inbreed lines, developed from a Brundage by Coda cross. 2,391 polymorphic DNA markers were used to create a linkage covering all chromosomes of wheat excluding 1D which could then be evaluated for associations with traits of interest. To identify markers linked to stripe rust resistance the population was evaluated under natural stripe rust infection in 9 site-year locations in 2005, 2010, and 2011 in the U.S. Pacific Northwest. Each line was rated for infection type and disease severity three to five times each season. Quantitative trait loci (QTL) analysis discovered five significant QTL associated with infection type and four associated with disease severity. QYrco.wpg-1B is a major Coda derived QTL on chromosome 1B which conferred a five-fold reduction in stripe rust infection type and greater than two-fold reduction in disease severity. To identify markers linked to freezing tolerance the population was cold acclimated prior to being frozen to -10.5, -11.5 and -12.5 ˚C in replicated freezing experiments performed in an artificial freezing chamber. Five to six week old plants were then evaluated for survival. A standardized percent survival at each minimum temperature as well as LT50 (temperature lethal to 50% of the plants) was calculated for each line. Seven QTL were identified that were associated with freezing tolerance. QFrbr.wak-5A on chromosome 5A was associated with freezing tolerance at all temperatures and with LT50. Markers linked to stripe rust resistance and freezing tolerance identified in this project will make useful additions to markers assisted selection programs.
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Details
- Title
- Molecular mapping of stripe rust resistance and freezing tolerance in winter wheat (Triticum aestivum L.)
- Creators
- Austin Joel Case
- Contributors
- Arron H. Carter (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Crop and Soil Sciences, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525079501842
- Language
- English
- Resource Type
- Thesis