Analysis Of Genetic Diversity Of Pak-choi Accessions Based On SSR Markers

We used31pairs of SSR markers to analyze the genetic diversity andrelationship among191cultivars （strains） of Pak-choi （B. rapa L. ssp.chinensis Makino）, and constructed DNA fingerprinting of47hybridizedcombination, in order to provide some molecular information to supportthe effective Pak-choi breeding. The average value of PIC was0.34; Theaverage value of expected gene heterogeneity （He） and Shannon’sInformation index of tested Pak-choi accessions were0.41and0.65,respectively. The Gst was20%, indicating80%of the genetic variationexisted within populations. Genetic diversity of tested Pak-choi cultivarsand strains from Jianghuai Plain was the highest among differentecological areas. In addition, genetic diversity of cultivars and strains fromChina was higher than those of Japan and South Korea. The level ofgenetic diversity among accessions bred by systematic selection washigher than that by other breeding methods. The191accessions could beseparated into5groups by UPGMA analysis. Meanwhile, the result ofgrouping germplasm genetic structure by STRUCTURE was basicallyconsistent with that by UPGMA clustering, two methods both showed thatspecies divided had certain correlation with geographic distribution. Theresult showed that the genetic diversity of191tested Pak-choi cultivarsand strains was relatively abundant, and most of them were clustered basedon geographic origin and genetic background. This study providedreference for Pak-choi breeding research.