Molecular Dissection for Boll Shedding in Upland Cotton Using Microsatellites

DNA markers application in marker-assisted breeding of cotton is handicapped due to low genetic diversity in cotton germplasm. The present study was designed to identify DNA markers, predominately simple sequence repeats (SSRs), associated with tolerance/resistance to heat stress as a consequence of boll shedding. To find out the genetic diversity a total of 24 cotton genotypes and 50 SSR primers were used. Total 288 alleles were produced with an average of 5.7 alleles per primer. Bootstrap cluster analysis used to generate a dendrogram that cluster the 24 accessions into two main clusters. Eleven out of 24 genotypes fall in a single cluster. Phenotypically H-4074 gives more diversity, while genotypically H-4074 sheared the same genetic background as H-4070, H-4091 and H-4090. Low genetic diversity was observed among both genotypic and phenotypic as maximum varieties fall in single group. This study helps for selecting diverse accessions with multiple phenotypic traits, which were drought to boll shedding. It suggests further elaborating the molecular genetic diversity by using new SSR marker to improve the yield of cotton cultivars. These preliminary results set the stage for initiating in depth marker-trait association studies, which will be instrumental for initiating marker-assisted breeding in cotton.