海岛棉遗传多样性的SRAP标记分析

Genetic Diversity Analysis of Sea-Island Cotton Cultivars Using SRAP Markers

利用SRAP标记,选用132对带型清晰的多态性引物,对我国引入海岛棉以来培育的36个国内品种及20个国外品种进行遗传多样性分析。共检测到419个多态性位点,每组合的多态性条带数从2-9不等,平均为3.17。利用NTSYS-pc2.10e软件采用Jaccard’s相似系数和UPGMA方法进行聚类分析。结果表明,大部分具有亲缘关系的品种聚在同类中,说明其结果与系谱具有一定的相符性;56个品种的平均遗传相似系数为0.497,变化范围在0.312-0.876之间,说明我国海岛棉品种在分子水平上存在较大差异;我国3个育种时期育成品种的平均相似系数依次为0.501、0.507和0.548,表明我国现在育成的品种相对于早期品种遗传多样性在逐渐降低。这些结果为我国海岛棉育种提供了有益的参考。

Sea-island cotton （Gossypium barbadense） is important due to its fine fiber quality. However, genetic diversity analysis of this specie is still poorly documented, which is important for in situ and ex situ germplasm conservation and useful for breeding programs. Using 132 out of 238 SRAP markers, genetic diversity of 56 sea-island cotton cultivars including 20 introduced from other countries was assessed, 419 polymorphism loci were detected. The number of polymorphic loci per primer ranged from 2 to 9 with an average of 3.17. Jaccard＇s genetic similarity coefficients were calculated and dendrograms were constructed by the unweighted pair group method of arithmetic average （UPGMA） using the NTSYS-pc version 2.10. The most of the accessions with relative relationship in their pedigrees were clustered into the same group. The genetic similarity coefficient of 56 accessions ranged from 0.312 to 0.876, with an average of 0.497, indicating that there was high level of genetic variation in the G. barbadense collections. The average genetic similarity coefficients of the domestic accessions in the first, second and third breeding periods were 0.501, 0.507, and 0.548, respectively, which implied that the genomic difference among the modem accessions has been gradually decreasing compared to that among the early accessions. These results suggest an overview of the genetic diversity of the sea-island cotton accessions, and provide a reference for breeders to develop new cultivars efficiently.