Inheritance and molecular mapping of an alien stripe-rust resistance gene from a wheat-Psathyrostachys huashanica translocation line

The wheat accession H9020-17-15 is a translocation line previously developed from interspecific hybridization between common wheat and Psathyrostachys huashanica Keng. This translocation line showed resistance to all Chinese stripe-rust races. In this study, the gene conferring rust disease resistance in H9020-17-15 was deduced originating from P. huashanica. This resistance gene, temporarily designated as YrHua, was confirmed to be dominant and monogenetically controlled. To molecularly map YrHua, a F2 segregating population comprised of 119 individuals was constructed on the basis of the hybridization between H9020-17-15 and a susceptible wheat line Mingxian 169. The linkage relationship with YrHua was evaluated for 166 simple sequence repeat (SSR) markers by analyzing this segregating population. YrHua was mapped to the long arm of chromosome 6A linked with the SSR marker Xgwm169 with a distance of 28.7 cM. Using AFLP to analyze the F2 population, two additional AFLP markers PM14 (301) and PM42 (249) were identified to be flanking YrHua at a distance of 5.4 and 2.7 cM, respectively. PM14 (301) was further developed into a 296-bp Sequence Tagged Site (STS) marker. These markers will be useful to combine YrHua with other genes for resistance gene pyramiding.