GENETIC DIVERSITY EVALUATION OF SOME ELITE COTTON VARIETIES BY RAPD ANALYSIS

Random amplified polymorphic DNA (RAPD) analysis was used to evaluate the genetic diversity of elite commercial cotton varieties. Twenty two varieties belonging to Gossypium hirsutum L. and one to G. arboreum L . were analyzed with 50 random decamer primers using the polymerase ch ain reaction (PCR). Forty nine primers detected polymorphism in all 23 cotton varieties, while one produced monomorphic amplification profil es. A total of 349 bands were amplified, 89.1% of which were polymorph ic. Cluster analysis by the unweighted pair group method of arithmetic means (UPGMA) showed that 17 varieties Can be placed in two groups wi th a similarity ranging from 81.51% to 93.41%. G. hirsutum L. varietie s S-12, V3 and MNH-93 showed a similarity of 78.12, 74.46 and 69.56% r espectively with rest of the varieties. One variety, CIM-1100, showed 57.02% similarity and was quite distinct. The diploid cotton G. arbore um L. var. Ravi was also very distinct from rest of its tetraploid cou nterparts and showed only 55.7% similarity. The analysis revealed that the intervarietal genetic relationships of several varieties is relat ed to their center of origin. As expected, most of the varieties have a narrow genetic base. The results obtained can be used for the select ion of possible parents to generate a mapping population. The results also reveal the genetic relationship of elite commercial cotton variet ies with some standard ''Coker'' varieties and the diploid G. arboreum L. var. Ravi (old world cotton).