Cluster analysis of major and candidate cultivars of wheat for dominant populations of stripe rust in seedling stage from Shaanxi, Gansu, Sichuan and Henan provinces
Abstract:A cluster analysis of two-hundred candidate wheat cultivars from Shaanxi, Gansu, Sichuan and Henan provinces recently was performed by using unweighted pair-group average method,based on the data from their seedling resistance reaction to six dominant isolates of Puccinia striiformis with the different virulence.Analysis results showed that the candidate cultivars from Sichuan had the best overall resistance with 80.82% immune one, followed by Shaanxi and Gansu provinces with 52.73% and 50.00% respectively, the candidate cultivars from Henan had the weakest resistance only with 22.22% immune one. Type and distribution of candidate cultivar resistance from Shaanxi Province were different clearly with few intermediate types, that indicated resistance genes to rust rather simplistic. Uniform distribution of resistant types showed the resistance gene complex in Gansu Province probably because of attention to the effective breeding to resistance diversity had been brought for recent years. The number of rust-resistant varieties in adult stage is more than the number of seedlings. The results indicate that there is a large variety of adult rust resistance varieties in the candidate cultivars.