Inheritance of Clubroot Resistance of Miniature Chinese Baby Cabbage and Molecular Markers-assisted Selection

The result confirms the feasibility of identifying clubroot resistance through molecular marker-assisted selection, and is of great significance for shortening identification time and improving breeding efficacy of new disease-resistant varieties. 1 Materialii and Methods 1.1 Materials The identification materials were clubroot-resistant Chinese cabbage CCR001, disease-susceptible baby cabbage CM002, and their F,, F2 and BCj offspring provided by Institute of Horticultural Crops, Yunnan Academy of Agricultural Sciences, and the control variety was highly susceptible variety 83-1. The amplification products were isolated by 6% denatured polyacrylamide gel electrophoresis, detected by sliver staining, and finally photographed for recording. 2 Results and Analysis 2.1 Clubroot resistance identification of baby cabbage Clubroot resistance of CCR.001, CM002, F,, F2, BC, and 83-1 were identified by bacterial soil inoculation method, and the incidence status was surveyed after 45 d. The results (Tab. 1) showed that the disease index of pařeni CCR001 was 1.67 (HR) ; the disease index of baby cabbage CM002 was 81.67 (HS); the disease index of Fļ and F2 were 1,11 and 21, with HR (F. ) and T (F2) in resistance evaluation, respectively. Resistance identification analysis demonstrated that the resistance/susceptibility ratios of F,, F2 and BC, were DO, 3:1 and D 1, conformed to Mendel's Laws of inheritance, indicating clubroot-resistimce of materials was controlled by a single dominant gene. 2.3 identification of clubroot resistance by molecular marker-assisted selection With the help of molecular marke r -assisted selection, the clubroot resistance of parents CCR001 and CM002, and îheir F,, F2 and BC, offspring were identified through TCR74 and PCK amplification. Li ei al. 131 studied the cross combination offspring of Gossypium barbademe L. "Pima90-53" and G. hirsutum L. using SSR molecular marker BNL3255-208 interlocked with Verticilliimi wilt resistance gene of C. barbadense, and proved that the molecular marker was effective in detecting VerticiUium wilt resistance gene and marker-assisted breeding.