Distribution of CRa in clubroot resistance (CR) cultivars of Chinese cabbage

Abstract

Clubroot resistance (CR) is an important trait for Chinese cabbage (Brassca rapa L. ssp. pekinensis). Since no CR genes had been found throughout Chinese cabbage lines originally, they were introduced from CR European turnips. Distribution of CR genes in the commercial cultivar is important information for CR breeding, but it has been scarcely known at molecular level. In this work, CR of 47 Chinese cabbage cultivars were analyzed phenotypically and genotypically. More than 80% of them exhibited high resistance phenotype, and all of the cultivars with high resistance were found to have CRa, one of the genes controlling CR. Majority of these cultivars were heterozygote for resistance, which is reasonable because CRa controls the resistance single-dominantly. This is the first work reporting the distribution of CR gene in Chinese cabbage cultivars and provides important and practical information for breeders and farmers. Further applications of CR genes are also discussed.