Abstract:

Waterlogging is one of the natural disasters frequently occur in Yangtze River Basin Cotton Area,which could cause abscission of cotton,blocked photosynthesis,reducing root absorption capacity,and result in production cuts. In order to elucidate the genetic variation of waterloggingtolerance related cotton germplasm,145 SSR markers spanning the whole genome were picked out.After screening,we chose 44 simple sequence repeat (SSR) makers which were explored to analyzed 48 upland cotton varieties.The results indicated that a total of 170 alleles,with an average of 3.86 alleles per locus were detected by the polymorphic 44 SSR primers.For the waterlogging tolerant accessions,mean polymorphism information content (PIC),the average effective numbers of alleles (Ne) and the average genotype diversity index (H′) were 0632,1710 4 and 0393 7 and 0628,respectively.For the waterlogging sensitive accessions,the PIC,Ne,and the H′ were 0628,1721 6 and 0399 4,respectively.The mean value of similarity coefficients were similar between waterloggingtolerance germplasms and waterlogging sensitive germplasms,varied from 0462 to 0925,and from 0462 to 0925,respectively.Relatively,the waterlogging tolerant germplasms exhibited relatively larger variation range.When the threshold value 058 was used in the UPGMA cluster analysis based on the Jaccard similarity coefficient,48 accessions were divided into two groups,in which the first category contained 39 varieties and the second category consisted of 9 accessions.NTSYSpc 22 and Excel software were applied to calculate the similarity coefficient between each two accessions,and the similarity coefficient was between 0355 and 0925,with an average value of 0629. The similarity coefficients of 23 waterlogging tolerant accessions were between 0580 and 0856,with an average value of 0665,The similarity coefficients of 25 waterlogging sensitive accessions were between 0580 and 0850,with an average value of 0663.The high genetic similarity coefficients we observed in most of the germplasms analyzed in the study indicated the waterlogrelated cotton accessions own narrow genetic base.The current study should be helpful for assessing cotton pedigrees in breeding elite varieties with high waterlogging tolerance,and studying the mechanism of waterlogging tolerance in upland cotton