Molecular Tagging Of New Stripe Resistance Genes YrSph And YrP81 In Wheat

Wheat stripe rust, caused by Puccinia striiformis West. f. sp. tritici, is one of the most important wheat disease. China is one of the highest epidemic regions of wheat stripe rust. And wheat suffers from stripe rust disease every year. At present, the simplicity of stripe rust resistance background in wheat cultivars have not changed although a lot of cultivars and breeding lines have been released. Therefore, identification of stripe rust resistances in different wheat cultivars or germplasm is very important for wheat improvement with stripe rust resistance. The objectives of this paper were to investigate the resistant gene in Triticum sphaerococcum Perciv. and T. aestivum L, through molecular marker analysis and pedigree analysis. The following results were obtained.1. Genetic analysis of the stripe rust resistance in the new breeding line D31, which was derived from T. sphaerococcum Perc., was carried out by inoculating mixed races of Chinese wheat stripe rust in field. In F2 population, the result indicated that wheat line D31 showed excellent resistance to the races of Puccinia striiformis West.f. sp. Tritic. A recessive gene was identified in D31 using the cross between D31 and SY-9571. Moreover, based on the pedigree analysis, the recessive gene was named YrSph, derived from Triticum sphaerococcum Perc (AS348),2. Four microsatellite markers Wmc149-200bp, Wmc246-180bp, Xgwm372-206bp and Wmc198-210bP on 2A were mapped to the gene YrSph locus, based on SSR molecular markers and Bulked sergeant analysis (BSA). Among of them, the allele of microsatellite locus Wmc246-180bp was linked to the YrSph with the genetic distance of 8.8 cM, while YrSph and other microsatellite markers showed random separation. Thus, the resistance gene was located on the long arm of chromosome 2A. The order of the four makers was that Centromere-Wmc149-YrSph-Wmc246-Xgwm372-Wmc198. YrSph was a new resistant gene to wheat stripe rust based on the analysis of resistant resource and the known resistance genes.3. Bulked sergeant analysis was used to identify AFLP markers linked to the gene YrP81 which was derived from T. aestivum L. and located on the short arm of chromosome 2B. Three AFLP markers E-AAC/M-CTAG-260bp EATC/M-CTAG-242bp and E-AAG/M-CTAG-200bp were linked with YrP81. Moreover, a new genetic linkage map of Yr P81 was obtained.