Molecular Mapping Of Powdery Mildew Resistance Genes In Wheat Line 91260

Powdery mildew, is one of the most devastating diseases of common wheat(Triticum aestivum L) that leads to severe yield loss and affects the quality of wheat. Exploring new resistant germplasm and mapping powdery mildew(Pm) resistance gene will facilitate to develop resistant cultivar. Chinese common wheat line 91260 was immune to Bgt isolate E09 at the adult stage and showed excellent resistance to mixed Bgt isolates. The research was aimed at exploring the genetic model of wheat line 91260, mapping the powdery mildew resistance genes in wheat line 91260 and developing the powdery mildew resistance genes linked markers. The closely linked maker will facilitate the fine mapping of resistance genes and marker assist selection(MAS) breeding and pyramid breeding. The achieved results were as follows:1. Genetic analysis used F1 and F2 population derived from a cross between 91260 and susceptible cultivar Yumai49, the powdery mildew resistance identification was conducted in two years in a net house. The F1 plants were highly resistant to powdery mildew and genetic analysis population segregated ratio was 9:7 in two years, indicating that 91260 carried two dominant and complementary effect genes2. In order to map resistance genes in wheat line 91260, the molecular mapping method was adopted. 1073 pairs of chromosome specific SSR marker evenly distribute on wheat chromosome were used for parent polymorphic screening, and 302 pairs showed polymorphic between line 91260 and Yumai49, the polymorphic markers were used for the genotyping of each F2 plants. Molecular mapping anchored the two resistance genes on 2AL and 2BL separately.(Temporarily designed Ml91260-1 and Ml91260-2). Ml91260-1 on 2AL was flanked by microsatellite markers Xcfa2263 and Xwmc170, genetic distance was 8.3cM and 4.1cM separately. Bioinformatics analysis indicated that Ml91260-1 located on the chromosome BinC2AL1-0.85 and near the centromere region. Based on the common wheat origin and the molecular analysis result, Ml91260-1 was different from the designated powdery mildew resistance genes on chromosome 2AL. Ml91260-2 on 2BL was flanked by simple sequence repeat(SSR) markers Xgpw4103 and Xwmc332 with the genetic distance of 4.1cM and 6.7cM respectively. Bioinformatics showed that Ml91260-2 was located on the distal region of chromosome 2AL, share the chromosome Bin2BL6-0.89-1.00. According to the molecular analysis and the inheritance model, Ml91260-2 proved to be a novel powdery mildew resistance gene.