Analysis of the Genetic Diversity of Some Main Cultivated Cotton Populations in China

Genetic diversity of 44 cotton varieties(including 38 Gossypium hirsutum and 6 Gossypium barbadense ) divided into 6 populations, were analyzed by inter simple sequence repeat (ISSR) markers according to their different origins. Eleven among 60 ISSR primers were chosen for their strong reproducibility and high polymorphism. A total of 90 fragments were amplified, in which the percentage of polymorphic bands (PPB ) was up to 77.78%. Popgene32 analysis indicated that genetic diversity of Xinjiang population(6 G. barbadense belonged to this population) was the highest [PPB = 91.43%, H (Nei's gene diversity index) = 0.3769, I (Shannon's information index)= 0.5464], then the CCRI (Cotton Research Institute of the Chinese Academy of Agricultural Sciences) population and Henan population followed it. However, there was no significant difference of genetic diversity among Shandong, Shanxi and Hebei populations, and the lowest genetic diversity was Shanxi population (PPB = 58.57%,H = 0.2484,I = 0.3587). Nei's total genetic diversity index indicated that 82.42%of variation was within populations while 17.58% was among populations; the gene differentiation (Gst) among populations was 0.1759, and the total gene flow (Nm) was 2.34. UPGMA (unweighted pair-group method using arithmetic averages) cluster analysis indicated that the relationship among Shanxi,Shandong and Hebei populations was nearest and gathered together first, then clustered with CCRI and Henan population. And last clustered with Xinjiang populations whose relationship was the furthest.