Studies on wheat stripe rust resistance conferred by Yrl6.

摘要

The wheat cultivar Cappelle Desprez (CD) carries the catalogued stripe rust resistance genes Yr3a, Yr4a and Yr16. Yrl6 is a single, dominant gene for adult plant resistance (APR) located on chromosome 2D. Despite virulence for Yr3a and Yr4a, the resistance in CD has remained moderately effective in Europe for many years. Based on this durability and assuming the gene is effective to South African (SA) pathotypes of Puccinia striiformis f. sp. tritici, the use of Yrl6 in wheat breeding was investigated. To transfer Yrl6 to a locally-adapted cultivar, CD was crossed with Palmiet (Plm). As Yr3a and Yr4a provide resistance against SA pathotypes, the first cycle of selection was aimed at isolating Yrl6 from these genes. Susceptible CD x Plm F_2 seedlingswere grown to maturity and tested for APR in a greenhouse, followed by repeated progeny testing in field trials to confirm stripe rust resistance. SSR markers found to be associated with Yrl6 by other workers failed to differentiate between resistant (R) and susceptible (S) CD x Plm plants.