Genetic diversity analysis of introduced and self-bred sea-island cotton (Gossypium barbadense L.) varieties based on SRAP markers

[Objective]The present experiment was conducted to investigate the genetic diversity of sea-island cotton germplasm accessions and provide references for application of sea-island cotton germplasm accessions and breeding elite varieties. [Method]Sequence related amplified polymorphism (SRAP) marker technology was used to analyze genetic diversity of 168 sea-island cotton cultivars. Sixteen pairs of primer combinations with clear band and high polymorphism were selected from 224 pairs of primer combinations. [Result]In total, 129 polymorphic loci were detected by sixteen pairs of SRAP primers, and each primer combination amplified 3 to 12 loci with an average of 8.06 loci. UPGMA cluster analysis results showed that the genetic similarity coefficient of sea-island cotton accessions ranged from 0.27 to 0.89, and the 168 sea-island cotton germplasm accessions were divided into four groups at coefficient threshold of 0.49: the 1st group mainly involved introduced foreign varieties at early stage, which contained Egyptian and Central Asian varieties, the 2nd group mainly included a series of Xinku varieties, part of Central Asian varieties and American Pima varieties, the 3rd group mainly contained a series of Xinhai varieties, part of Central Asian varieties and Soviet Union varieties, the 4th group just only has Giza 85 in it. [Conclusion]The genetic similarity coefficient of sea-island cotton cultivars ranged widely, which showed great difference and rich genetic diversity among the 168 accessions.