Abstract:

To analyze genetic linkage and map the location of purple gene（BrPur）controlling purple inner leaves trait of Chinese cabbage，a F₂ population constructed by the single-plant-selfing of F₁ hybridized from homozygous purple heading line‘14S839’and homozygous orange heading line‘14S162’was used. The field investigation of head color shows that the separation proportion of purple heading individuals to non-purple heading individuals fitted to the ratio of 3︰1 in F₂ population，which means that the purple heading of Chinese cabbage was a dominant phenotype and consistent with genetic pattern of a single dominant gene. Then，two flanking linkage markers，A710 and A714，were obtained by a modified BSA method with 297 SSRs in whole genome，and the BrPur was primarily mapped on linkage group A07 based on the location of the two flanking markers sequence in BRAD. Subsequently，two novel flanking markers，CL-12 and B214-87，were developed by cloning and homology sequence alignment analysis of Br4CL3 and Bra004214 involved in anthocyanin related genes in previous reports. Finally，we verified the linkage relationship of all markers using F₂ population，and found that their genetic map obtained by Join Map 4.0 was consistent with the result from Plant Genotype Matrix of all non-purple crossover individuals，which placed CL-12 and B214-87 flanking two side of BrPur locus at genetic distances of 3.1 cM and 3.5 cM，respectively. 

Key words: Chinese cabbage, purple heading leaf, molecular marker, linkage analysis, gene mapping