Molecular Characterization of Elite Cotton Cultivars using ISSR Markers

Genetic variability and relationship between varieties are of great importance for cotton breeding. ISSR marker systems were used for identification and genetic diversity analysis of elite G. hirsutum, G. arboreum and introgressed lines. 12 cotton genotypes were subjected to ISSR analysis using 55 ISSR primers. PCR products were subjected to agarose gel electrophoresis and the banding patterns were compared among 12 elite cotton varieties of diploid, tetraploid and introgressed cotton. Out of 55 ISSR primers tested, 15 were scorable, producing 101 marker bands with 83 being polymorphic. The primer IS-08 generated the greatest number of polymorphic markers. The ISSR markers were found to be reproducible and polymorphic. A dendrogram constructed from ISSR data classified 12 cotton genotypes into two major clusters, one containing six genotypes belonging to G. hirsutum cultivars and the other contained 4 genotypes belonging to G. arboreum cultivars. Two introgressed cultivars PAIG-8/1 and PAIG-27 showed highest level of genetic similarity with G. arboretum varieties. ISSR technique was thus found to be efficient method for detecting DNA polymorphism useful for DNA fingerprinting and genetic diversity analysis in cotton.