Medicinal plants have been given greatsignificance in recent years due to its demand in industry for human and animal welfare and alluring market prices(Lubbe and Verpoorte 2011). India is called as the “Botanical Garden” of theworld due to variegated climatic ecosystem which is suitable for cultivationfor medicinal plants. India being one of theworld’s 12 mega biodiversity countries needs to conserve its resources wherethey are being exploited and should be grown commercially to avoid theirsusceptibility to extinction because of indiscriminate use.Among the various medicinal plants, Withaniasomnifera (L.) Dunal(Winter cherry, Ashwagandha or Asgandh of family Solanaceae is animportant medicinal plant that finds extensive use as a potential herb in thetraditional system of medicine as a ‘rasayana’ and ‘medhya rasayana’.
The similarities betweenroots of Ashwagandha and ginseng roots have led to it being called as Indianginseng (Tripathi et al. 1996).W.somnifera is a geneticallysimple species (2n = 48; n = 24; largely self-pollinated) most suited todevelop cultivars for commercial production of novel sterols and alkaloids(Singh and Kumar 1998).
It grows in dry and sub-tropical regions. The major Ashwagandha cultivating states areMadhya Pradesh, Rajasthan, Punjab, Uttar Pradesh, Haryana, Gujarat andMaharashtra among which Madhya Pradesh alone is having more than 4000 ha areafor cultivation. Its roots, leaves and seeds are used in preparation ofAyurvedic and Unani medicines, to combat a wide range of diseases fromtuberculosis to arthritis. In the plant, important part is roots, leaves andberries because they contain alkaloids called as “Withanolides” (Gupta et al.1996). Themajor biochemical constituents of W. somnifera are steroidal alkaloids andlactones, a class of constituents together known as withanolides (steroidallactones with ergostane skeleton). Ongoing trials and research on animal support therole of ashwagandha’s root and leaf extracts in different disorders anddiseases and possess properties like anticancer, antioxidant etc.
(Chopra etal. 2004; Cooley et al. 2007; Murthy et al. 2010; Rasool et al. 2000;Padmavathi et al. 2005; Bhattacharya et al. 2006) and act as source of arestorative drug (Asthana and Raina 1989). There is no influence of environment on molecular markers and that is thereason for their wide application in genetic diversity assessment among W.
somnifera (L.) Dunal genotypesand to identify duplicated accessions within the germplasm collections. Most important development has occurred in thefield of molecular genetics with the emergence of molecular marker. Thesemarkers are used for the detection and exploitation of DNA polymorphism (Semagnet al.
2010). DNA markers are unaffected by physiologicalconditions and environmental factors thus reliable for informativepolymorphisms since genetic composition is unique for each species. Molecularmarkers have provided a powerful new tool for breeders to search for newsources of variation and to investigate genetic factors controlling quantitativelyinherited traits. Genetic polymorphism helps in distinguishing plants at inter-and/or intra-specific level not only in medicinal plants but also in cereals,cash, plantation and horticulture crops. Themost important role of conservation is to preserve the process of geneticdiversity and development in the viable population of ecology and commerciallyviable varieties / genotypes to avoid possible extinction (Rout et al.
2010). Differenttypes of marker systems have been used for biodiversity analysis. These includeRFLP, SSR, RAPD and the AFLP.
RAPDand ISSRmarkers are two molecular approaches that have been used to detect variationamong plants. Systematicevaluation and quantification of the variability from the present study willserve as one step towards providing accurate genetic information for furtherbreeding programmes for Withaniaimprovement. The assessment of variation would provide us acorrect picture of the extent of variation, further helping us to improve thegenotypes for biotic and abiotic stresses. The main objective of this study was to characterizethe Withania genotypes usingmorphological and molecular markers in order to evaluate the genetic diversityand relationships among genotypes lines.