GENOME-WIDE ASSOCIATION MAPPING AND POPULATION STRUCTURE FOR STRIPE RUST IN PAKISTANI WHEAT GERMPLASM

Stripe rust disease caused by Puccinia striiformis is one of the utmost destructive foliar diseases of wheat all around the world. The most effective strategy to control this disease is to develop and grow resistant varieties. To identify the genomic regions responsible for resistance, 294 Pakistani hexaploid wheat accessions were subjected to genome-wide association studies (GWAS). These lines were characterized phenotypically for stripe rust response at seedling stage in controlled conditions in Pakistan and in fields near Mount Vernon and Pullman in Washington, United States. A targeted amplicon sequencing approach was used to genotype the wheat germplasm with 787 of SNP markers. Twenty-four genotypes showed resistance to stripe rust in controlled conditions in Pakistan. In Washington, 193 and 97 genotypes showed resistance at Mount Vernon and Pullman, respectively. GWAS results showed that seven and three loci were associated with resistance observed at the seedling stage under controlled and field conditions, respectively, and only one locus on chromosome 7A was significantly associated with adult plant resistance. This study identified resistance loci in Pakistani wheat germplasm that can be used in breeding resistant wheat varieties.