Fine Mapping of a Gene Conferring Wheat Soil-Borne Wheat Mosaic Virus Resistance.

Wheat soilborne mosaic (WSBM), caused by wheat soilborne mosaic virus, is a serious viral disease of winter wheat grown in the Great Plains and eastern wheat producing regions in the USA. WSBM disease can significantly reduce wheat tiller number and plant height, therefore, reduce kernel weight, test weight and grain yield up to 80%. Developing wheat cultivars with resistance to WSBM is the only feasible strategy to reduce the losses incurred by WSBM. Previously, we identified a closely linked SSR marker Xgwm469 to a resistance gene on chromosome 5D by association mapping. To further fine map the gene, a wheat 9K SNP chip was used for further association analysis using 192 wheat cultivars. Two new SNP markers were identified to be highly associated with the resistance gene. The SNPs and Xgwm469 were mapped close to the gene on 5D using a F6 derived RIL population from the cross between resistant parent Heyne and susceptible parent Trego. The two SNPs were converted into KASP markers and can be easily used for marker-assisted selection to improve WSBM resistance.