Fine Mapping of a Major QTL for Resistance to Soil-Borne Wheat Mosaic Virus in Wheat.

Soil-borne wheat mosaic virus (SBWMV) is a serious viral disease of winter wheat worldwide. To improve SBWMV resistance, we used wheat Infinium iSelect Beadchips with 9K, 92K wheat SNPs to genotype a natural population of 205 wheat accessions. SNPs that were significantly associated with the resistance were identified by association mapping, this gene was mapped on 5D using two F₆-derived recombinant inbred lines (RILs) by crossing two resistant parents ‘Deliver’ and ‘Wesley’ to a susceptible parent ‘OK03825’. To saturate the gene region for cloning of the gene, genotyping-by-sequencing (GBS) that uses next generation sequencing technology was performed in the two populations and more closely linked SNP markers to the resistance gene were identified. The high-density linkage map helped us to pinpoint the gene to a smaller region on chromosome 5D. KASP assays for selecting the gene were released for marker-assisted selection to improve wheat resistance to SBWMV in breeding.