Genetic Analysis Of Landrace Mazha Resistance To Powdery Mildew And The SSR Markers Linked To Resistance Gene

Powdery mildew, caused by Blumeria graminis f.sp. tritici, is one of the most important diseases of common wheat worldwide. Growing resistant cultivars is the most economical, effective and environment-friendly way to control the disease. Wheat landrace Mazha shows good resistance to most powdery mildew isolates tested. The gene that Mazha carries is different from genes identified currently. The analysis of genetic and molecular marker of the gene resistant to powdery mildew will facilitate utilization of the resistance gene, accelerate breeding process and be helpful to pyramiding of resistance genes in wheat breeding.1: The inheritance of the resistance to powdery mildew carried by the Chinese wheat landrace Mazha was analyzed by reciprocal crosses between Mazha and the susceptible cultivar Chancellor. Resistance of Mazha and its F₁ hybrid progenies and F₂ and testcross (TC₁) populations was analyzed genetically by artificial inoculation with isolate E30 of B. graminis f.sp. tritici at seedling stage in green-house. Genetic analysis shows that a single recessive gene determined the resistance reaction of Mazha to E30 under normal temperature in both crosses, which fitted the 1R:3S ratio that is conferred by a recessive gene. The analysis of TC₁ population, which fitted the 1R:1S ratio, confirmed the above results. The results imply that the nuclear gene controls the rresponse of Mazha to E30.2: Based on the genetic analysis, SSR molecular markers were used to analyze the resistance gene in Mazha. 178 pairs of microsatellite primers from wheat 5D and 7B were used to analyze the DNA polymorphisms between the resistant parent, the susceptible parent, the resistance pool and susceptible pool. Three SSR markers on chromosome 7B were found, among the population of 145 wheat plants, to be linked to the resistance gene. The SSR markers were wmc396, wmc218 and gwm400, and their genetic distance from the gene was 14.5 cM, 22.2 cM and 36.7 cM, respectively. Molecular marker analysis using gwm396, wmc218 and gwm400 indicates that the three makers were linked to the resistance factor in Mazha and located on 7BL chromosome. This gene is different from the known gene Pm5e, which locate also on long arm of 7B, via analysis the location of the two genes. We could suggest that the gene from Mazha is most likely a novel resistance gene, and designated temporarily as Mlmz.