Genetic Analysis and Mapping of the Purple Gene in Purple Heading Chinese Cabbage

To analyze genetic linkage and map purple gene (BrPur) controlling purple inner leaves trait of Chinese cabbage, a F2 population was constructed by selfing a F1 plant from homozygous purple heading line '14S839' and homozygous orange heading line '14S162'. The phenotype investigation of head color showed that the segregation ratio of purple to non-purple individuals was consistent with the expected ratio of 3:1, which indicated that purple inner leaves trait is controlled by a single dominant gene. A total of 297 SSRs in whole genome of Chinese cabbage were tested by modified Bulked Segregant Analysis (BSA) method. Two linked markers flanking BrPur, A710 and A714, were obtained and BrPur was mapped on linkage group A07 based on the sequence of these two markers. Subsequently, two new markers flanking BrPur, CL-12 and B214-87, were developed based on two known anthocyanins-related genes, Br4CL3 and Bra004214. Genetic mapping of all markers in the F2 mapping population showed CL-12 and B214-87 linked to BrPur with the genetic distance of 3.1 cM and 3.5 cM, respectively.