Inheritance Analysis And SSR Molecular Markers Of Leaf Rust Resistance Gene In Wheat

Wheat leaf rust, caused by Puccinia triticina, is one of the most important wheat diseases inthe world, which widely distributed in the wheat growing areas throughout the world and causedwheat yield losses of 5-15ï¼…or greater while disease occurred severely. Genetic resistance is themost economical, effective and safety method of reducing yield losses due to leaf rust. Resistanceto leaf rust can be most fully utilized based on the genetic knowledge of genes for leaf rustresistance in wheat resistance resources. Continued efforts to develop and characterize new genesfor leaf rust resistance are important to wheat breeding for resistance and control of disease.Seedling resistance of elite wheat lines SW92, 92-624, Jing16348 and their F1, F2 and BC1generations from the crosses with the susceptible wheat line Mingxian169 respectively were testedwhile inoculated with to PHT of Puccinia triticia. The results showed that SW92 had onerecessive gene for resistance to PHT; 92-624 had two complementary genes for resistance to PHT,one was dominant and another was recessive; The resistance to leaf rust pathotypes PHT inJing16348was controlled by two dominant and one recessive complementary genes.Microsatelite technique was used to mark the wheat leaf rust resistant gene in SW92. DNAsamples extracted from the F2 individuals were pooled into two separate groups for BulkedSegregant Analysis (BSA) to identify the molecular markers linked to the resistant gene, 371 pairsof microsatelite primers were screened between the parents and progenies. Two SSR markersWMC494 and WMC737 located on 6B chromosome of wheat were found to be linked to theresistance gene, with genetic distance of 3.4cM and 15.0cM, respectively. According to consensusSSR genetic map of wheat, this resistance gene is located on short arm of the 6B chromosome,different from known dominant genes Lr36 and Lr53 on the 6B chromosome. We suggest that thisgene for leaf rust resistance from SW92 most likely be a novel resistance gene, and temporarydesignated LrSW92.