AFLP and SAMPL markers for characterization of genetic diversity in Terminalia arjuna: a backbone tree of Tasar silk industry

Overexploitation of Terminalia arjuna by the Tasar silk, pharmaceutical, leather, and other industries has led to gradual depletion of its germplasm resource and genetic diversity. Information on its existing gene pool is currently lacking. We report the first evaluation of genetic variation in this tree, using amplified fragment length polymorphism (AFLP) and selective amplification of microsatellite polymorphic loci (SAMPL) markers. The study consisted of (1) characterization of genetic diversity at interzonal and intrazonal levels, (2) comparison of diversity within and among populations, and (3) comparison of efficiency of the two marker systems. The germplasm used in the present study had a wide genetic base, which is evident through the high level of genetic diversity observed, as expected for a widespread, long-lived tropical species. The clustering obtained after interzonal genetic diversity analysis of T. arjuna is not region specific, a reflection of the lack of any defined population structure in this genus in India. The high value of r obtained through Mantel's test for evaluation of cophenetic correlation in cluster analysis indicated the high fitness of the accessions to a group. The region-specific bands obtained during the present investigation can be used as diagnostic markers for authentication and to identify raw materials for herbal drug preparations.