Genome-Wide Association Mapping for Stripe Rust Resistance in Domesticated Emmer Wheat (Triticum turgidum ssp....

Wheat (Triticum aestivum L.) is one of the major crops and a staple food for approximately 35% of the world population. Wheat production is constantly threatened by stripe rust, one of the most devastating wheat diseases, which is caused by Puccinia striiformis f. sp. tritici (Pst). Improving the disease resistance of wheat cultivars is the most efficient and sustainable way to control stripe rust. In this study, we aimed to explore the novel resistance resources in a collection of 180 cultivated emmer wheat accessions (T. turgidum ssp. dicoccum) collected from 32 countries on five continents. The cultivated emmer wheat accessions were genotyped by wheat Illumina iSelect 9 K single-nucleotide polymorphism (SNP) array, and phenotypes were evaluated in a greenhouse using four races and in five field environments. Conducting a genome-wide association study, we identified 14 quantitative trait loci (QTLs) associated with stripe rust resistance. Two QTLs, QYr.emmer-4A.2 and QYr.emmer-6A, confer all-stage resistance, and 12 QTLs, located on chromosomes 1A, 2A, 2B, 3A, 3B, 4A, 5A, 5B, 7A, and 7B, confer adult plant resistance (APR) to stripe rust. Compared with the known stripe rust resistance QTLs, most of the QTLs identified in this study are very likely novel QTLs. The APR QTL, QYr.emmer-7A, was consistently detected among multiple data sets from different environments and was validated using a biparental mapping population. The SNPs, simple sequence repeat markers and the genomic loci identified in this study will provide very useful information for QTL mapping and resistance breeding programs.