Withania somnifera: Diversity and phylogeny - An overview

The diversity and phylogenetic relationships within Solanaceae are interesting. Withania in spite of being an important genus of the family has not found proper attention for such studies and even species delimitation within the genus is debatable. Different authors at different points of times classified Withania somnifera into different morphological forms and even split it into two different species. Similarly, there are various uncertainties about phylogenetic relationships below the family level in Solanaceae and so also for Withania . In the present study morphological as well as molecular data have been used to give an overview of the diversity and phylogeny of Withania , particularly of W. somnifera . The morphological studies,  RAPD, ISSR, cytochrome P450 sequence derived primers, SSR analogues and ITS sequence data support that the species has a lot of polymorphism and can be bifurcated into two well-demarcated varieties. However, there is no conclusive support for dividing the species into more than two forms or splitting the species into two different species, rbc L gene sequence data supports a close relationship of the genus with Physalis and associated genera.