Résumé
Objective: To investigate the ecological and genetic diversity, climatic factors, edaphic factors morphological and reproductive characters and RAPD analysis of medicinal plant species Pterolobium hexapetalum in two hills viz., Maruthamalai (arid) and Chennimalai (very arid), which is located in Coimbatore and Erode districts, Tamil Nadu. Methods: The present research was carried out by using a random amplified polymorphic DNA (RAPD) analysis was made to determine the genetic variation between the two populations of the medicinal shrub, Pterolobium hexapetalum in an environmental gradient. Among the five primers tested, the OPN7 (80 %) and OPN17 (71.4 %) produced higher polymorphism was used in RAPD analysis. Results: The results of RAPD analysis showed the presence of 51 individual bands were formed, out of which, 29 were polymorphic bands which showed the existence of genetic variation between populations. A dendrogram was constructed based on Jaccard’s coefficient to determine the degree of genetic relationship among the two populations and analysed. The primers OPN7 and OPN17 were clustered together at a genetic distance level 10. Considering the elevation and proximity, the temperature ranges from 18 °C to 37.6 °C in Maruthamalai hill and 20 °C to 39.4 °C in Chennimalai hill. Conclusion: From the morphoecological studies the results indicated that both arid and very arid climatic conditions showed slight differences in their vegetative and reproductive characters.