title: Genetic Architecture of Resistance to Stripe Rust in a Global Winter Wheat Germplasm Collection.
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 complex 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 1175 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, five 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.
authors.affiliation: Department of Crop and Soil Sciences, Washington State University, Pullman, Washington 99164-6420.
authors.forename: Peter
authors.identifier: 0000-0002-7223-7838
authors.initials: P
authors.lastname: Bulli
authors.affiliation: Department of Plant Sciences, University of California, Davis, California 95616.
authors.forename: Junli
authors.initials: J
authors.lastname: Zhang
authors.affiliation: USDA-ARS Genotyping Laboratory, Biosciences Research Laboratory, Fargo, North Dakota 58102.
authors.forename: Shiaoman
authors.initials: S
authors.lastname: Chao
authors.affiliation: USDA-ARS, Wheat Health, Genetics and Quality Research Unit, Washington State University, Pullman, Washington 99164 Department of Plant Pathology, Washington State University, Pullman, Washington 99164.
authors.forename: Xianming
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Crop and Soil Sciences, Washington State University, Pullman, Washington 99164-6420 m.pumphrey@wsu.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Pumphrey
mesh_terms: D001487:Basidiomycota / Q000235:genetics* / Q000472:pathogenicity; D002874:Chromosome Mapping; D060467:Disease Resistance / Q000235:genetics*; D055106:Genome-Wide Association Study; D005838:Genotype; D000069600:Plant Breeding; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci / Q000235:genetics; D000068098:Seed Bank; D014908:Triticum / Q000235:genetics / Q000254:growth & development / Q000382:microbiology*
keywords: QTL-tag SNP; association mapping; disease resistance; genetics of immunity; hexaploid wheat; yellow rust