Microsatellite marker for yellow rust resistance gene Yr5 in wheat introgressed from spelt wheat

Yellow rust of wheat caused by Puccinia striiformis f. sp. tritici has been periodically epidemic and severely damaged wheat production in China and throughout the world. Breeding for resistant cultivars has been proved to be an effective way to resolve the problem. A yellow rust resistance gene, Yr5 , derived from Triticum spelta shows immunity or high resistance to the most popular isolates Tiaozhong 30 and 31 in China. Establishment of DNA markers for the Yr5 gene will facilitate marker-assisted selection and gene pyramiding in the breeding programme. Since the Yr5 gene was cytologically located on the long arm of chromosome 2B, By33, the donor of Yr5 , was crossed and backcrossed with the susceptible line 441, and BC3F2 and BC3F3 segregating populations were screened for polymorphism by using 11 microsatellite primers mapped on chromosome 2B. A marker, Xgwm501-195 bp/160 bp, was found to be linked to Yr5, with a genetic distance of 10.5-13.3 cM.