Postulation of Seedling Resistance Genes in 20 Wheat Cultivars to Yellow Rust (Puccinia striiformis f. sp. tritici)

The gene postulation, cluster analysis and pedigree analysis of 20 wheat cultivars to 28 physiological races of yellow rust (Puccinia striiformis) were conducted under greenhouse conditions. The spectrum of their resistance were compared each other. None of the 20 cultivars were resistant to all the test pathogens. The cultivars containing resistance genes Yr5 and Yr24 were not find and genes Yr8, Yr19 and Yr27 could not be postulated from cultivars tested due to the susceptibility to all isolates used. A total of 6 probale seedling yellow rust resistance genes or gene combinations (Yr1, Yr2, Yr2 + YrHVII, Yr3 + unknown, Yr3 + Yr4, YrAlba) were postulated in the wheat cultivars (Atou, Flanders, Maris Huntsman, Bouquet, Holdfast, Elite Lepeuple, and Vilmorin 27). The gene combination Yr2+YrHVII with the highest frequency (35%) was present in 7 cultivars. The Yr genes present in some wheat cultivars could not be postulated because of non-matching virulence combinations with any of known genes. Cluster result showed that Yr2 and Yr3 are the most important genes in the cultivars. The 13 cultivars are believed to have the pedigree of Noe, which was selected from South Russian wheat. These results will be useful for wheat breeding and provide information about genetic control of wheat yellow rust.