Genetic Analysis And Molecular Mapping Of Stripe Rust Resistance Gene In Wheat Translocation Lines Derived From Leymus Mollis Trin Hara

Stripe rust, caused by Puccinia striiformis. f. sp. tritici, is one of the most widespread and destructive wheat diseases worldwide. Frequent epidemics of stripe rust have caused considerable yield losses. Growing resistant cultivars is the most-effective, economic and environmentally sound approach to control stripe rust. However, high genetic variation and the ability of the pathogen to evolve into new races with added new virulence always have been the major limiting factors in a successful long-term management of stripe rust when race-specific resistance genes are used. Therefore,it is an important to explore and utilize alien germplasm for wheat programn in the future.The objectives of this study were to identify new stripe rust genes in three Triticum aestivum -Leymus mollis translocation lines, and map a stripe rust resistance gene in wheat translocation line M8657-1 using Simple sequence repeat (SSR) techniques. The result showed as follows:1.Seedlings of 3 wheat translation lines M8657-1,M853-1,M853-4 and susceptible cultivar Mingxian169 were tested for resistance to the seven Chinese PST isolates CYR29,CYR30,CYR31,CYR32,Su-4,Su-11,Su-14 under the controlled greenhouse. The result indicated that M8657-1,M853-1,M853-4 have effective resistance at all-stage to the dominant races in China.2. To identify new genes for resistance to stripe rust, seedlings of the parents, F2 progeny and F3 lines derived from cross between resistant lines and susceptible cultivar Mingxian169 were tested in greenhouse. The stripe rust resistance analysis showed:The resistance of M853-4 to the races CYR30, Su-11, Su-14 was conferred by a single dominant gene,respectively, while the resistance to the race Su-4 was conferred by two complementary dominant genes. The resistance of M853-1 to the races CYR29, Su-11 was conferred by three complementary genes with two dominant genes and one recessive gene, the resistance to the races CYR30, CYR31 was conferred by two complementary genes with one dominant genes and one recessive gene, the resistance to the race Su-4 had the characters of cytoplasm genetics,as female parent, it carries two independent dominant genes, while as male parent, it carries three complementary genes with two dominant genes and one recessive gene. The resistance of M8657-1 to the races Su-11, Su-14 was conferred by a recessive gene, respectively.3. To molecular map a new stripe rust resistence gene in wheat translation line M8657-1, F1, F2 progeny derived from the cross between resistance line M8657-1 and susceptible cultivar Mingxian169 were tested with the race Su-11of P. striiformis f. sp. tritici in greenhouse. Simple sequence repeat (SSR) techniques was used to develop molecular markers linked to the resistance gene in wheat line M8657-1. 208 pairs of wheat SSR primers were used to test the two parents, as well as resistant and susceptible bulks. Subsequently, three SSR markers were employed for genotyping the F2 population. The result indicated that the stripe rust resistance in line M8657-1 was conferred by a recessive gene, temporarily designated as YrLm1, located closely to the chromosome7DL and flanked by three SSR markers GDM67,WMC150 and WMC671, with the genetic distances of 5.0 cM, 9.7 cM and 11.8cM, respectively.