Evaluation of genetic variability using random amplified polymorphic DNA markers in selected species of Solanum L. - a potential medicinal genus.
Molecular techniques have been found to be more useful and accurate for the determination of both interspecific and intraspecific genetic variation among plants. Randomly amplified polymorphic DNA (RAPD) markers, in particular, have been successfully employed for determination of intraspecific genetic diversity among several plant species. Solanum, the genus selected for the present study is the largest and complex genus of the Solanaceae. It comprises more than 1,500 species with geographical origin in Asia and Africa. The centers of diversity are in South America, Australia and Africa, while relatively less diverse species are found in Europe and Asia with a promise as primarily in medicinal followed by vegetable crop. The present investigation was carried out to assess the genetic diversity of 16 selected species including one variant accession based on RAPD mark ers. Most of the selected species are having potential medicinal properties and used in modern system of medicine as well as in traditional system by the ethnic societies of Kerala against various ailments. The 234 polymorphic bands were scored using 15 random primers employed suggesting 100% polymorphism across the genotypes. UPGMA dendrogram cluster analysis indicated three distinct clusters, one comprising accessions of S. mauritianum, S. capsicoides (spiny accession) and S. trilobatum, while second included four species viz., S. pseudocapsicum, S. mammosum, S. capsicoides (lax spiny accession) and S. giganteum. S. seaforthianum, S. erianthum, S. nigrum, S. melongena var. insanum, S. torvum, S. violaceum ssp. multiflorum, S. macrocarpon, S. aculeatissimum, S. violaceum ssp. violaceum and S. wendlandii formed third larger cluster indicating its genetic relatedness. The overall grouping pattern of clustering corresponds well with principal component analysis confirming patterns of genetic diversity observed among the species. The result provides valid guidelines for collection, conservation and characterization of Solanum genetic resources in particular, the medicinal species.