Inheritance And SSR Mapping For Wheat Stripe Rust Resistance Gene(S) Derived From Leymus Mollis

Stripe rust，caused by Puccinia striiformis f. sp. tritici (Pst), is one of the mostdevastating diseases of wheat throughout the world．Growing resistant cultivars is the mosteconomical, effective and environment friendly method to control this disease. However, highgenetic variation and the ability of the pathogen to evolve into new races with added newvirulence always make cultivars easily lose their resistance Therefore, exploring andidentifying new stripe rust resistance genes, and use it in gene pyramiding become more andmore important and necessary. The breeding is necessary for the delay of the toxicity variationof stripe rust races, prolong service life of disease-resistant, widen the wheat resistant geneticdiversity. It is also very necessary in wheat stripe rust sustainable control measures. Fivetranslocation lines derived from hybridization and cross between Triticum aestivum andLeymus mollis were systematically analyzed and revealed genetic mechanism of translocationlines resistance to stripe rust, and SSR markers of one stripe rust resistence gene intranslocation line M852-1were identified. The results are as follows:1.Seven current popular yellow rust races CYR29、CYR31、CYR32、CYR33、T4、Su11-4and Su11-7were used to inoculated26translocation lines derived from hybridization andcross between Triticum aestivum and Leymus mollis for resistance evaluation. The resultsshowed that14translocation lines possess resistance to all the tested Pst races and5translocation lines possess resistance to6tested Pst races.2. The results of inheritance analysis for stripe rust resistance in four translocation linesindicated that: one dominant gene resistance to CYR33was estimated for M8724-1and onerecessive gene resistance to CYR32was estimated for M851-1; M8725-2had one dominantgene and one recessive gene to CYR33；two complementary dominant genes resistance toCYR31were estimated for M853-2.3. To identify and map the gene(s) conferring resistance to stripe rust，Pst races (CYR29,CYR32, CYR33and Su11-7) were selected to test the F1, F2, F3and BC1generations derived from the cross M852-1/Mingxian169at the seedling stage. The genetic analysis showed thatone dominant resistance gene to CYR29and one recessive resistance gene to CYR32, CYR33and Su11-7respectively, were estimated for M852-1.4. The gene conferring resistance to CYR32in M852-1was mapped by linked SSR(simple sequence repeat) markers. By using SSR to analyze the144individuals in the F2segregating population, three markers on chromosome2BS (Xbarc124, Xbarc200andXgwm429) were identified and linked with the resistance gene YrM852(temporarilydesignated) at the distance of6.3,5.6,9.7cM, respectively. Furthermore, based on the sourceof the gene YrM852, molecular detection and chromosome location, YrM852might be a novelstripe rust resistance gene. It will provide useful information for molecular assisted selection.