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ARS Home » Pacific West Area » Pullman, Washington » WHGQ » Research » Publications at this Location » Publication #326447
Title: Genetic architecture of resistance to stripe rust in a global winter wheat germplasm collection

Author
item BULLI, PETER - Washington State University
item ZHANG, JUNLI - University Of California
item Chao, Shiaoman
item Chen, Xianming
item PUMPHREY, MICHAEL - Washington State University

Submitted to: G3, Genes/Genomes/Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/11/2016
Publication Date: 5/26/2016
Citation: Bulli, P., Zhang, J., Chao, S., Chen, X., Pumphrey, M. 2016. Genetic architecture of resistance to stripe rust in a global winter wheat germplasm collection. G3, Genes/Genomes/Genetics. doi: 10.1534/g3.116.028407.

Interpretive Summary: Virulence shifts in populations of the wheat stripe rust pathogen are a major challenge to resistance breeding. The majority of known resistance genes are already ineffective against current races of the pathogen, necessitating the identification and introgression of new sources of resistance. We report the results of genetic characterization and genome-wide association analysis (GWAS) for resistance to stripe rust in a core subset of 1,175 accessions in the National Small Grains Collection (NSGC) winter wheat germplasm collection based on genotyping with the wheat 9K single nucleotide polymorphism (SNP) assay and phenotyping of seedling and adult plants under natural stripe rust epidemics in four environments. High correlations among the field data translated into high heritability values within and across locations. Population structure was evident when accessions were grouped by stripe rust reaction. GWAS identified 127 resistance loci that were effective across at least two environments, including 20 with significant genome-wide adjusted probability values. Based on relative map positions of previously reported genes and quantitative trait loci (QTL), 5 of the QTL represent potentially new loci fro stripe rust resistance. This study provides an overview of the diversity of stripe rust resistance in the NSGC winter wheat germplasm core collection, which can be exploited for diversification of stripe rust resistance in breeding programs.

Technical Abstract: Virulence shifts in populations of Puccinia striiformis f. sp. tritici (Pst), the causal pathogen of wheat stripe rust, are a major challenge to resistance breeding. The majority of known resistance genes are already ineffective against current races of Pst, necessitating the identification and introgression of new sources of resistance. Germplasm core collections that reflect the range of genetic and phenotypic diversity of crop species are ideal platforms for examining the genetic architecture of desirable traits such as resistance to stripe rust. We report the results of genetic characterization and genome-wide association analysis (GWAS) for resistance to stripe rust in a core subset of 1,175 accessions in the National Small Grains Collection (NSGC) winter wheat germplasm collection based on genotyping with the wheat 9K single nucleotide polymorphism (SNP) iSelect assay and phenotyping of seedling and adult plants under natural disease epidemics in four environments. High correlations among the field data translated into high heritability values within and across locations. Population structure was evident when accessions were grouped by stripe rust reaction. GWAS identified 127 resistance loci that were effective across at least two environments, including 20 with significant genome-wide adjusted P-values. Based on relative map positions of previously reported genes and QTL, 5 of the QTL with significant genome-wide adjusted P-values in this study represent potentially new loci. This study provides an overview of the diversity of Pst resistance in the NSGC winter wheat germplasm core collection, which can be exploited for diversification of stripe rust resistance in breeding programs.