Genetic Analysis and Molecular Tagging a Novel Yellow Rust Resistance Gene Derived from Synthetic Hexaploid Wheat Germplasm M08

Yellow rust of wheat(caused by Puccinia striiformis Westend.f sp.tritici Eriks.)has been periodically epidemic and severely damaged wheat production in China.The development of resistant cultivars could be an effective way to reduce yield losses of wheat caused by yellow rust.Rust reaction tests and genetic analysis indicated that M08,the synthetic hexaploid wheat derived from hybridization between Triticum durum(2n=6X=28;genome AABB)and Aegilops tauschii (2n=2X=14;genome DD),showed resistance to current prevailing yellow rust races at seedling stage,which was controlled by a single dominant gene,designated as YrAm.Bulked segregant analysis was used to identify microsatellite markers linked to gene YrAm in an F2 population derived from cross M08(resistant)×Jinan 17(susceptible).Three microsatellite marker loci Xgwm77,Xgwm285,and Xgwm131 located on chromosome 3B were mapped to the YrAm locus. Xgwm131 was the closest marker locus and showed a linkage distance of 7.8 cM to the resistance locus.Thus,it is assumed that YrAm for resistance to yellow rust may be derived from Triticum durum and is located on the long arm of chromosome 3B.