Estimation of genetic divergence among some cotton varieties by RAPD analysis

Total genomic DNA from 15 cotton varieties were analysed to evaluate genetic diversity among them through random amplified polymorphic DNA (RAPD) analysis, with 30 random decamer primers using the polymerase chain reaction (PCR). A total of 370 bands were observed, with 12.3 bands per primer, of which 91.6% were polymorphic. OPM-16 produced the maximum number of fragments while the minimum number of fragments was produced with the primer OPM-18. Cluster analysis by the unweighted paired group method of arithmetic means (UPGMA) showed that 15 varieties can be placed in five groups with a similarity ranging from 0.48 - 0.86. Maximum similarity was observed between H-777, H-974 and H-1098 (0.86). Interestingly, these varieties have been developed at one breeding center. The analysis revealed that the intervarietal genetic relationship of several varieties is related to their center of origin. Most of the varieties have a narrow genetic base. These results were well in accordance with previous reported results. The RAPD analysis indicates that it may be a more efficient marker than morphological marker, isozyme and restriction fragment length polymorphism (RFLP) technology. The results obtained can be used in selecting divergent parents for breeding and mapping purposes.   Key words: Cluster, cotton varieties, diversity, RAPD, genetic similarities.