Validation of a set of informative simple sequence repeats markers for variety identification in Pak-choi (Brassica rapa L. ssp chinensis var. communis)

摘要

A core set of 21 simple sequence repeats (SSR) markers was developed for Pak-choi (Brassicarapa ssp.chinensis var.communis) variety identification. We initially selected 74 SSR markers which exhibited high polymorphism and reproducibility in SSR detection from 2129 SSRs. Using the 74 SSR-based dendrogram for 45 inbred lines as calibration, 21 core SSRs were selected out. The utility of this core set SSRs was firstly tested in 45 inbred lines and finally verified in 102 commercial varieties. We also constructed a molecular ladder for each core SSR as a reference standard. Diversity analysis of this core SSR panel in 102 varieties demonstrated that each marker generates 2-3 alleles (averaged 2.33), with polymorphism information content values ranging from 0.01 to 0.56 (averaged 0.31). The averaged values of Shannon information index, observed heterozygosity, expected heterozygosity and Wright's fixation index were 0.59, 0.43, 0.38 and -0.09, respectively. Furthermore, the 21 SSR-based classifications for 102 varieties were consistent with traditional classification based on morphology. This core SSR panel represents an effective tool for genetic variation analysis in Pak-choi.