SSR Markers and Preliminary Chromosomal Location of a Powdery Mildew Resistance Gene in Common Wheat Germplasm N9134

A powdery mildew resistance gene, originating from wild emmer (Triticum dicoccoides Thell.) accession 'AS846', was transferred to a common wheat line N9134. N9134 was highly resistant to the prevailing Erysiphe graminis f. sp. tritici Race Guanzhong 4 in Shaanxi Province. F1 plants of the crosses susceptible cultivars (Shaan 160 and Shaanyou 225)×N9134 were highly resistant to the powdery mildew race and the ratio of resistant and susceptible plants in F2 progeny fitted the expected 3 to 1. The results indicated that powdery mildew resistance of N9134 at seedling stage was controlled by a single dominant gene. The gene is temporarily designated PmAS846.92 and 84 F2 plants of the crosses Shaan 160×N9134 and Shaanyou 225×N9l34 were used for SSR analysis, respectively. 3 of 66 wheat microsatellite primer pairs WMS67, WMS213 and WMS37 generated polymorphic DNA fragments between the resistant and susceptible plants DNA pools. By analyzing the polymorphic markers in these segregating populations, the microsatellite locus Xgwm67 located on chromosome 5BL was found to be linked to the resistance gene PmAS846 with the estimated genetic distance of 20.6 cM, suggesting this gene might be located on the long arm of chromosome 5B.