Dissertation
IDENTIFYING NOVEL DISEASE RESISTANCE AND DROUGHT TOLERANCE GENES IN A SYNTHETIC NAM POPULATION
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000003111
Handle:
https://hdl.handle.net/2376/122438
Abstract
Wheat was domesticated approximately 10,000 years ago when the tetraploid grassTriticum turgidum (AABB) is thought to have hybridized with the diploid grass Aegilops tauschii Coss. (DD), resulting in hexaploid wheat Triticum aestivum (AABBDD). Most research confirms the D-genome was the last genome to be introduced, is the least diverse, and tends to have fewer known markers. This distinct lack of diversity has hindered breeders and geneticists; diversity could lead to higher yields, better end-use quality, and increased tolerance to biotic and abiotic stress. Synthetic wheat is a tool that can be used to incorporate genetic diversity and provide disease resistance genes not found in common germplasm. Synthetic wheat is made by recreating the hybridization that led to T. aestivum using different subspecies of both T. durum and Ae. tauschii. The result is a primary synthetic hexaploid wheat (AABBDD) that has diverse alleles and trait combinations, and can be readily crossed into adapted germplasm. In addition to being a source of novel disease resistance genes, synthetic wheat lines are also known to have more diverse root systems. The objective of this dissertation was to evaluate a synthetic nested
association mapping population, the D-genome Nested Association Mapping Population (DNAM) for novel abiotic and biotic stress tolerance genes. Multiple projects involved screening selections of the DNAM population for resistance to stripe rust (Puccinia striiformis), Fusarium Crown Rot (Fusarium culmorum and Fusarium pseudograminearum), and Cereal Cyst Nematode (Heterodera avenae and Heterodera filipjevi). One novel gene was found to confer resistance to both H. filipjevi and avenae cereal cyst nematodes. Moderate resistance to fusarium crown rot was also detected, but is contributed both from the recurrent parent of the population as well as by several A. tauschii donor parents. A subset of the DNAM was also used for a three-year, nine environment drought study. A genome-wide association study (GWAS) revealed three quantitative trait loci (QTL) for grain protein content and quality across all nine environments, and nine QTL contributing to those same traits within individual environments.
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Details
- Title
- IDENTIFYING NOVEL DISEASE RESISTANCE AND DROUGHT TOLERANCE GENES IN A SYNTHETIC NAM POPULATION
- Creators
- Nikayla Maree Strauss
- Contributors
- Kimberly G Campbell (Advisor)Arron Carter (Advisor)Michael Pumphrey (Committee Member)Scot Hulbert (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
- Publisher
- Washington State University
- Number of pages
- 185
- Identifiers
- 99900651793901842
- Language
- English
- Resource Type
- Dissertation