Genetic Diversity Analysis on Local Upland Cotton Cultivars in Xinjiang Based on SSR Markers

Abstract

Xinjiang, the largest prior cotton production region in China, has made remarkable genetic improvement in upland cotton(Gossypium hirsutum L.). There has been a substantial raise in yield potential, cotton-planting area and total production in Xinjiang since 1970s. The new upland cotton cultivars have contributed a lot to yield increase, in which Xinjiang-bred upland cotton varieties play an important role in cotton production in both Northern and Southern Xinjiang. However, seldom research on genetic basis of genetic diversity and pedigree relationship has been evaluated in upland cotton varieties in Xinjiang so far. This study aimed to reveal the genetic diversity of 94 upland cotton varieties in Xinjiang by genome analysis using SSR markers. The results indicated that SSR molecular markers could be employed in revealing the genetic diversity. One hundred and fifty-three polymorphic loci were detected by amplified with 54 pairs of primers with allelic variation of 2–6 per primer pair and the average of 2.93. The genotypic diversity(H′) spanned from 0.0439 to 0.7149, with the average of 0.4491. The PIC value ranged from 0.0430 to 0.6640, and the average was 0.3831. The coefficients of genetic similarity among 94 tested cultivars varied from 0.3846 to 0.9835. And more than 71.9% of similarity coefficients fell into the interval of 0.601–0.800, indicating that the genetic similarity among the cultivars was high, whereas the genetic diversity might not be abundant. According to UPGMA cluster analysis, 94 tested cultivars were divided into two clusters when the threshold valve was given as 0.63, showing the relatively simple genetic relationship among the upland cotton varieties in Xinjiang, and relatively low genetic diversity and narrow genetic basis. The results of molecular clustering on genetic diversity of upland cotton coincided in large degree with the pedigree relationship. In con-clusion, there is no much difference on molecular level among Xinjiang-bred upland cotton varieties. Materials with much wider genetic backgrounds are suggested to be used to diversify the genetic basis of cotton varieties in Xinjiang.