Microsatellite Marker Mapping Of A Stripe Rust Resistance Gene In Chinese Native Wheat Variety Chike (Su 1900)

Wheat stripe rust is one of the most important diseases throughout the world, especially severe in China.To use resistant cultivars is the most economical,effective and environmentally sound method to reduce damage caused by stripe rust.However, resistance of most commercial wheat cultivars will "breakdown" as continual appearance and development of new races of the stripe rust pathogen.Since the appearance of PST race CY32 in China,major wheat cultivars have become susceptible,resulting in the 2002 epidemic.Therefore,it is urgent to breed and use new wheat cultivars with effective resistance genes to stripe rust.Chike(Su1900),a Chinese native wheat variety,was resistant to the physiological race of CY32.Whereas the shortage of new stripe rust resistance resources for wheat breeding and some effective stripe rust resistance resources have not been ultilized reasonably,to carry out studies on genetic analysis of resistance,chromosomal localization and development of molecular markers for the stripe rust resistance genes in the Chinese native wheat variety Chike has important significance.In this study,a set of different progenies derived from the cross between a susceptible variety Taichung29 and the Chinese native wheat variety Chike were prepared.Genetic analysis of resistance was carried out by inoculating representative main races of Chinese wheat stripe rust in green house.Chromosomal localization of a major stripe rust resistance gene in Chike was performed by using SSR method combined with nullitetrasomic analysis.The main results gained are as follows:1.The Chinese native wheat variety Chike,Taichung29,and the F₁,F₂,BC₁,F₃ of Chike×Taichung29 were incubated with the physiological race CY32.Genetic analysis indicated that resistance to CY32 of the pathogen in the variety was controlled by one dominant gene.2.Through SSR analysis,more than 400 SSR primers were screened,and five SSR markers Xwmc44,Xgwm259,Xwmc367,Xcfa2292,Xbarc80 were found linked to the resistant gene.These five markers were all on chromosome 1BL.3.The data of genetic linkage analysis of the 5 SSR markers and the resistant gene YrChk was calculated and mapped by the software Mapmaker 3.0b.YrChk gene was flanked by the 5 markers.Xwmc44,the closest to YrChk gene,was on the side close to the centromere,with a genetic distance of 8.3 cM to YrChk gene.The other 4 markers Xgwm259,Xwmc367,Xcfa2292 and Xbarc80 were on the side apart from the centromere,their genetic distance to YrChk gene were 9.1 cM,17.2 cM,20.6 cM and 31.6 cM respectively.4.Nullitetrasomic analysis was conducted with these SSR makers Xwmc44, Xgwm259,Xwmc367,Xcfa2292 and Xbarc80.Result indicated that the five SSR bands amplified by the five SSR primers were on wheat chromosome 1B.Combined with the SSR markers mapping results,we concluded that the major stripe rust resisrance gene in Chike was on the chromosome 1BL.5.Assessment of stripe rust resistance of related varieties indicated that Chike, which carrying YrChk,showed resistant to CY32(IT 0～0;).The wheat varieties Clement(Yr9),Lovlin10(Yr9),Vilmorin23(Yr3a),Hybrid46(Yr3b),Lemhi(Yr21), Lalbahadur(Yr29)showed infection to CY32(IT3～IT4).The results indicated that YrChk should be a new stripe rust resistance gene.6.Through AFLP analysis,more than 100 AFLP primers were screened,but the AFLP markers which are linked to the YrChk gene were not found because of the limited time.