Cabbage Resistance To Soft Rot Traits Ssr Molecular Marker Analysis

Chinese cabbage (Brassica rapa ssp. pekinenesis) is an important vegetable in China and south-east Asian countries. Soft rot disease has been one of three most important diseases of Chinese cabbage. The pathogen was identified as E. carotovora.subsp.carotovora (Ecc) .Therefore, the analysis of genetic characters of soft rot and study in the location of genes conferring resistance to soft rot disease in Chinese cabbage are essential and urgent.A set of resistant and susceptible self-bred lines of Chinese cabbage and their F2 populations were used in this study. Fourty-eight hours after inoculation with Ecc, resistant phenotypes were recorded and the disease severity index was calculated.148 pairs of EST-SSR primers were screened by SDS-PAGE, and 17 showed polymorphism between highly resistant samples and susceptible samples. The 17 polymorphic EST-SSR primers were then used to analyze the F2 population between two resistant and susceptible self-inbred lines of Chinese cabbage. The F2 population consisted of 142 Chinese cabbage individuals. It was found that 2 primer pairs were not steady and didn't show polymorphism. Thus, only 15 (10. 13% of the total screened primer pairs) pairs of polymorphic EST-SSR primers were used for further analysis. After analyzing the statistic correlation between the SSR markers and the severity of soft rot, four EST-SSR primers termed S4,S7,S9,S10 showed significant correlation.