Genetic divergence of colored cotton based on inter-simple sequence repeat (ISSR) markers

The management of colored cotton is an agricultural activity widely adopted by farmers located at Brazilian semiarid region. The fiber colors currently available are still limited to green and shades of brown, however, there is possibility to broaden the variability for this trait by using accessions from Gossypium Brazilian bank in breeding programs. Therefore, it is necessary to know the genetic diversity of available accessions in the collection. Here, the genetic divergence in colored fiber accessions was estimated in order to identify promising candidates for further use in hybridization procedures of cotton improvement. DNA of twelve accessions were extracted from leaves and used in inter simple sequence repeat-polymerase chain reaction (ISSR-PCR) assays, using commercial oligonucleotides. The genetic divergence was estimated by clustering-unweighted pair group method with arithmetic mean (UPGMA) method. Five groups were clustered among them, three were contributive results for further use in hybridization procedures, including Brazilian cultivars and Peruvian accessions. Based on level of divergence, we suggest that lines generated from these materials could generate news shades of fiber colors in further use for selection procedures in cotton breeding.   Key words: Gossypium, molecular marker, variability, genetic improvement.