| Powdery mildew, caused by Erysiphe. graminis f. sp. tritici, is one of the most important devastating diseases of common wheat worldwide. Breeding for cultivars with resistance to powdery mildew is the most economical, effective and environmentally safe way to control the disease. The advent of molecular markers and construction of molecular marker maps of wheat has facilitated the studies on resistance genes. Wild relatives of wheat have constituted a large reservoir for powdery mildew resistance, and are a rich gene pool for disease resistance. The objectives of the present study were to identify and tag powdery mildew resistance gene in 3749-10 with SSR and RAPD makers. The main results obtained were as follows:1.The resistance pattern of a F2 population(186 individuals) derived from cross of 3749-10 (resistant) and jingshuang 16 (susceptible). Genetic analysis and chi-square test of phenotype of F2 population showed that the ratio of resistant and susceptible plants in F2 fitted the expected 3 to 1 ratio. The results indicated that powdery mildew resistance of 3749-10 at seeding stage was controlled by a single dominant gene.2.Eleven of 186 DNA samples extracted from the F2 population were pooled into two separate groups for bulked segregant analysis (BSA).To identify the molecular markers to the resistant gene, 2 of 411 wheat micrisatellite primer pairs Xgwm44 and Xbarc170 and 1 of 100 RAPD primer S3 generated polymorphic DNA fragments between the resistant and susceptible plants DNA pools. By analyzing the polymorphic markers in these segregating populations, the microsatellite locus Xgwm44 and Xbarc170 located on chromosome 4A were found to be linked to the resistance gene with the estimate genetic distance of 13.2 cM and 18.4 cM, respectively. RAPD primer S3 linked to the resistance gene with the estimate genetic distance of 7.8 cM . It is suggested that this gene might be located on chromosome 4A.
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