利用SSR分析四倍体棉种多态性

利用SSR标记对60份四倍体棉种材料进行遗传多样性分析，其中包括42份陆地棉野生种系。结果显示, 从1 050对SSR引物筛选出的95对SSR引物均能在60份材料间扩增出稳定明显的多态性条带，共检测出660个片段，其中多态性片段584个，占88.5%。每个位点的等位基因为2~12个，平均每对引物6.1个。UPGMA聚类分析显示, 42份材料的相似性系数(GS)在0.306~1.000之间，平均成对相似系数为0.493。95对引物的多态信息含量(PIC)的变幅为0.278~0.905，基因多样性(H¢)的变幅为0.451~2.451, 有效等位基因数(Ne)在1.385~10.490之间变动。SSR标记在陆地棉野生种系及四倍体棉种间均可反映丰富的遗传多样性信息，其中陆地棉与陆地棉野生种系中阔叶棉的亲缘关系最近，海岛棉和达尔文棉的亲缘关系非常相近，黄褐棉和毛棉相对较近，陆地棉与其他4个棉种的亲缘关系最远。

Genetic Diversity of Allotetraploid Cotton Based on SSR Markers

There are five allotetraploid cotton species including two cultivated varieties, G. hirsutum and G. barbadense, and three wild species, G. darwinii watt, G. mustelinum Miers ex Watt and G. tomentosum. Wild cotton contains not only wild species but also wild types of cultivated varieties, such as G. hirsutum L. races. Research on genetic diversity relationships among cultivated and wild cotton species is necessary for better understanding of cotton evolution and good use of wild resources. The aim of this study was to evaluate the genetic diversity of five allotetraploid cotton species and 42 wild types of upland cotton using SSR markers. A total of 95 from 1050 pairs of SSR primers were used to amplify the 60 accessions of germplasm, which could produce steady and clear polymorphic bands. Six hundred and sixty DNA fragments were scored among all materials, 584 polymorphic bands were obtained, accounting for 88.5% of the total bands. The allele number (NA) per SSR locus was 2–12, with the average of 6.1. UPGMA Cluster analysis based on SSR data showed that the genetic similarity (GS) coefficient among 42 accessions of germplasm ranged from 0.306 to 1.000, the mean genetic similarity (GS) coefficient was 0.493. For 95 primers, the polymorphism information content (PIC) was from 0.278 to 0.905. The Shannon-Weaver diversity index (H¢) ranged from 0.451 to 2.451, and effective number of alleles (Ne) varied from 1.385 to 10.490. The results showed that there is a wide genetic variation in wild types of upland cotton and allotetraploid cotton tested by SSR markers. The genetic relationship is nearest between upland cotton and G. hirsutum var. latifolium, very close Gossypium barbadense L. and G. darwinii watt, G. mustelinum Miers ex Watt and G. tomentosum L. Nuttall ex Seeman a bit close and farthest between upland cotton and others.