Genetic Diversity Analysis of Widely Cultivated Sea-island Cultivars (Lines) in Xinjiang Using SSR Markers

In order to better guide Sea-island cotton breeding in Xinjiang, a total of 187 pairs of SSR primers which spanned the whole genome of cotton were selected to evaluate the genetic diversity of 20 widely cultivated Sea-island cotton cultivars (lines) in Xinjiang. Fifty-five pairs (29.4%) of SSR primers showed polymorphism, and 97 polymorphic loci were obtained with an average of 1.8 polymorphic loci per SSR marker. The polymorphism information content (PIC) for a marker locus was 0.095~0.829 with an average of 0.560. Pairwise genetic similarity coefficients of the 20 cultivars (1ines) ranged from 0.18 to 0.93, with a mean of 0.44. UPGMA cluster analysis showed that the 20 cultivars (1ines) were clustered into two main groups; and when the threshold value was set to 0.43 and 0.48, respectively, the two groups were divided into 2 sub-groups, respectively. The results of this study indicated that the genetic diversity of the 20 cultivars (1ines) was broad and the risk in production was low.