Intraspecific morphological and genetic variations within the population of Calotropis gigantea L WT Aiton from the Shivalik Hills

Abstract

ABSTRACT newlineGenetic diversity among organisms is an evolutionary character which may be due to the variety of alleles and genotypes present among individuals within a population of a single species. Genetic diversity provides a raw material for natural selection and therefore, playing an important role in maximizing species adaptation to biotic and abiotic environmental changes. Instead of these, for the conservation of wild plant species the assessment of genetic variation is important. Calotropis gigantea (L) W.T. Aiton is an important medicinal, drought resistant and relatively high degree salt tolerant wild plant of the Himalayas. In India, it grows up to 900 meters, whereas, in Himachal Pradesh it is found in districts, Sirmaur (Si), Hamirpur (H), Chamba (C), Solan (S), Bilaspur (B) and Kangra (K). In Himachal Pradesh there is very less diversity of C. gigantea as compared to C. procera, therefore, present study deals with the detection and analysis of genetic and morphological variations among the population of C. gigantea in Shivalik hills of Himachal Pradesh through RAPD and morphological techniques, respectively. newlineFor the detection of morphological (qualitative) variations, three-three plants were selected from five districts (Si, S, U, H and K) of Himachal Pradesh which are approximately three km far away from each other. Different qualitative characters studied were habit, external shape of tree, stem, leaf shape, flower characters (calyx, corolla, androecium, and gynoecium), fruit and seed. On the basis of above qualitative characters, no variation was observed in all the districts except H. It was observed that C. gigantea, collected from H district had one larger calyx than the others which could be due to any epigenetic change or result of any other gene regulatory mechanism. On the other hand, intraspecific genetic variations of five genotypes from five districts were analyzed by random amplified polymorphic DNA (RAPD) technique using five random operon primers. Five primers have generated a total of