Genetic Analysis And Molecular Mapping Of Resistance To Stripe Rust Of The Resistance Sources YLP-7and Wuhan2

Wheat Stripe rust, caused by Puccinia striiformis f. sp.tritici（PST）, is one of the mostdestructive diseases of wheat worldwide. Resistance is the best approach to control thedisease. Aplication of cultivars resistance is the most important method of controlling striperust of wheat, but a cultivar breakdown in several years because of cultivars single andresistance gene overcomed by new pathogen. The wheat genetic basis of our country is scarcebecause most varieties have the same or similar resistance genes. In recent years, withepidemic of strains CYR32and CYR33et al, especially the new pathogenicity of races instripe rust towards Yr26were come out, the main cultivars of wheat-growing areas in Chinalost their resistance to stripe rust. Therefore, it must be of great significance to lastingcontrolling strip rust to explore and create new resistance materials and genes, to breed newrust-resistant varieties, to increase diversity of resistance genes and provide rich materialreserve for genetic transformation of wheat disease resistance. So the research of cultivarsresistance received more and more closed attention. Researchers are trying to find means ofovercoming cultivars “breakdown” from inheritance mechanisms.1.To determine the inheritance of resistance in YLP-7, exploring and using the resistancesources in wheat breeding program. The field resistance of YLP-7to stripe rust was evaluatedin artificial nursery with mixed races at Yangling; and the resistance spectral was investigateat seedling stage under greenhouse with twelve prevalent isolates of Pst; and the inheritanceof resistance was investigate with F₁plants, F₂plants, F₃lines and BC1population derivedfrom a cross of YLP-7and the susceptible line Chinese Spring, inoculated with two isolatesCYR29and CH42respectively. The results showed that YLP-7has high level field resistanceto stripe rust, and were immuned or nearly immuned to all tested Pst isolates in seedling stage.The data of inheritance showed that the resistance to CYR29and CH42were conferred by thesame single dominant gene. Consequently,YLP-7is a significant resistance germplasmresource in stripe rust, suggesting to use in wheat breeding for disease resistance in the future,cultivating well varieties of resistance cultivars, in order to increase the resistance geneabundance in wheat stripe rust. 2. Wuhan2, a hexaploid winter wheat （Triticum aestivum L.） cultivar with resistance toFusarium head blight. A F2population was developed from a cross between stripe rustsusceptible cultivar Mingxian169and resistant cultivar Wuhan2. The two parents,179F2plants and their F2:3lines were evaluated for the response to current Chinese stripe rust racesCYR30and CYR31in the greenhouse. DNA bulked segregate analysis was applied andresistance gene analog polymorphism （RGAP） techniques were used to identify molecularmarkers linked to the resistance genes. The chromosomal locations of RGAP markers weredetermined using Chinese Spring nulli-tetrasomic lines. Subsequently, the simple sequencerepeat （SSR） markers showing linkage with the resistance gene were used to genotype the179F2plants. A genetic map consisting of five RGAP and six SSR markers was constructed.Yrwh2was located on chromosome3BS, and SSR markers Xwmc540and Xgwm566were5.9and10.0cM proximal to the resistance locus, respectively. The chromosomal location of theresistance gene suggest that the locus is different from previously reported stripe rustresistance genes Yr30, QYr.ucw-3BS, Yrns-B1, YrRub and QYrex.wgp-3BL mapped to thisregion，and probably it is a new resistance gene. The resistance gene and their closely linkedmarkers are potentially useful for improving resistance to stripe rust in wheat breeding.