Identification of Introgressed Alien Segments and Phenotypic Analysis in BC2F1 Progenies from Chinese Cabbage (Brassica campestris ssp. pekinensis) and Non Heading Chinese Cabbage (B. campestris ssp. chinensis)
Abstract：Chromosome segment introgression lines (CSILS) are important materials for the study of QTL fine mapping, the interaction between QTLs and mechanism of heterosis. molecular marker assisted selection (MAS) is an important means to identify the introgression segments during the creation of CSILs. In order to clarify the introgression and the lost of alien chromosome segments, and the effects of alien chromosome on the phenotype of Chinese cabbage (Brassica campestris ssp. pekinensis) during the process of establishing Chinese cabbage-non heading Chinese cabbage (Brassica campestris ssp. chinensis) chromosome introgression lines, InDel markers identification and phenotypic analysis of BC2F1 progenies from Chinese cabbage 85-1 and non heading Chinese cabbage JinglvNo.2 were carried out. The results showed that 186 of 264 tested InDel markers from Chinese cabbage were polymorphism between 85-1 and JinglvNo.2, among them, 160 specific markers of JinglvNo.2 compared to 85-1 were screened out, which arranged on 10 chromosomes of B. rapa and the number of InDels on each chromosome varied from 6~26. 52 InDel markers on different position of 10 chromosomes were applied to identify the BC2F1 population. Among them, 50 InDel markers were identified out in 196 BC2F1 plants at different frequency, the plants containing 8 alien chromosome segments were the most common. 40 plants that containing 50 specific markers of JinglvNo.2 and carrying the relatively few alien segments were selected out by analysis of Graphical Geno Typing (GGT) software, which could be further used for the establishment of the introgressed lines with single alien segment. Phenotypic characters of BC2F1 plants, such as leaf shape, leaf size, leaf color and bolting tolerance, flower color showed a serial separation. The results not only provide technical support for the creation of the set of Chinese cabbage-non heading Chinese cabbage chromosome segment introgression lines, but also provide the material for studying the effects of different alien segments on plant phenotypic variation.
