Chromosome Location And Molecular Maker Of Two Chinese Differentials For Resistance Genes To Puccinia Striiformis West.

Wheat stripe rust, caused by Puccinia striiformis f.sp. tritici West., is one of the most important wheat diseases in the world, especially in China. Due to the lack of sexual stage in P. striiformis, using wheat differential cultivars becomes the only way to identify the virulent genes of the pathogen. To define the resistant genes and the inherit characteristics of differential cultivars becomes one important step which facilitates the studies on physiological specialization, monitoring race dynamics and analysing resistant genes, with that we can communicate between countries.Resistance test and genetic analysis suggested the near isogenic line Taichung 29*6/Jubilejna II carry resistance to race Su-1 at seedling stage, which was determined by a single dominant gene. This gene is designated as YrJu4. A chromosome 2BS microsatellite primer WMS501 was identified to be linked to YrJu4 in a F2 population derived from the cross between the isogenic line and the recurrent parent. Another chromosome 4B microsatellite primer WMC335 was not linked to YrJu4 gene. Thus the resistance gene YrJu4 was located on the long arm of chromosome 2BL. The genetic distance between Xgwm501 and the gene was determined as 1.2 cM by Mapmaker 3.0 and the LOD value was 74.54. According to the analysis, the YrJu4 gene is a new gene. We suggest name the YrJu4 gene as Yr34. SSR primers for chromosomes 6A, 3B and 6B were used to identify the gene carried in the near isogenic line Taichung 29*6/Hybrid 46 according to the genes, which are Yr3b, Yr4b and YrH46, in Hybrid 46. Polymorphic DNA bands were identified between the line and the recurrent line (Taichung 29), which lacks these genes. The result of primer screening indicates that ten primers are polymorphic between the parents.A Chinese differential cultivar Funo was crossed with a susceptible cultivar Mingxian 169. Seedlings of the parents, F1, F2 and backcross progenies were evaluated for resistance to the Indian race 2E16. The result indicates that there are one dominant and one recessive complementary gene that are effective against the Indian race 2E16. However, the monosomic analysis results indicated there was one resistant gene to the Indian race 2E16 and the gene was located on chromosome 3B. The current study shows that it is different from the known genes.