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Dissertation - University Access Only
Doctor of Philosophy (PhD)
Department / School
Significant reductions in Wheat (Triticum aestivum L.) grain yield and grain quality have been caused by biotic and abiotic stresses. In the case of disease, development of resistant genotypes generally provides optimal control. The objective of this study was to identify quantitative trait loci (QTL) that confer resistance to three of the most important wheat diseases in the Northern Great Plains - stem rust (Puccinia graminis. f. sp. tritici), bacterial leaf streak (Xanthomonas campestris translucens) and tan spot (Pyrenophora tritici repentis). Bi-parental and multi-parental populations, as well as composite interval mapping, genome-wide and forward selection approaches were used to identify QTL. A QTL (likely, Sr8a) on chromosome arm 6AS was associated with stem rust resistance to race TRTTF, and the present study reports for first time a set of markers near the gene that can be used for marker assisted selection. We also located QTL on chromosomes 2B, 4A, and 7B that confer resistance to bacterial leaf streak (BLS). All QTL together explained 19.6 and 37.9% of the total variation for the resistance at Aurora and Volga, SD respectively. Fifty doubled-haploids lines insensitive to tan spot ToxA were identified. Genes tsn1 (insensitivity to ToxA) and likely Tsc1 (insensitivity to chlorosis produced by ToxC) were located to chromosomes 5B and 1A, respectively. Genotypes and the markers associated with the resistance they express to these diseases can be utilized in the development of new resistant cultivars.
Library of Congress Subject Headings
Wheat -- Genetics
Wheat -- Genome mapping
Wheat -- Disease and pest resistance -- Genetic aspects
Includes bibliographical references
Number of Pages
South Dakota State University
Guerrero Chavez, Rosa, "Bi-Parental and Multi-Parental Based Mapping of Quantitative Traits in Spring Wheat" (2015). Electronic Theses and Dissertations. 1661.