Received: 20 August, 2007. Accepted: 17 November, 2007. Original Research Paper Medicinal and Aromatic Plant Science and Biotechnology ©2007 Global Science Books Morphological and Molecular Diversity in Pterocarpus santalinus L.f - an Endemic and Endangered Medicinal Plant K. Padmalatha • M. N. V. Prasad * Department of Plant Sciences, University of Hyderabad, Hyderabad, Andhra Pradesh, 500 046, India Corresponding author: * mnvsl@uohyd.ernet.in ABSTRACT The present study is the first report of morphological and molecular variations in accessions of Pterocarpus santalinus L.f (endemic, endangered, commercially and medicinally very important) collected from Kerala, Karnataka and mostly from Andhra Pradesh, India. It addresses the determination of genetic variation among accessions using few morphological parameters and RAPD markers. A total of 27 accessions were collected out of which morphological variations were characterized for 14, 15 and 16 and molecular variations for 15 of them. Morphological data opened up lot of variations among the accessions. Molecular investigation revealed that, out of the 40 primers screened, 26 primers selected for the data analysis generated a total of 217 scorable markers, all of which were polymorphic. This high proportion of polymorphism i.e., almost 100%, was found with 53 unique markers. Cluster analysis based on Dice’s coefficient showed two major groups indicating that in cross-pollinated plants, high levels of differentiation among accessions exist. The grouping of these accessions was independent of the geographical distance. The significant molecular variations in the accession collected from Tirupathi when compared to other accessions need to be further investigated. Hence the results of the present study can be viewed as a starting point for future research on the population and evolutionary genetics of this species and understanding such variation would facilitate their use in various conservational management practices, rootstock breeding and hybridization programmes. _____________________________________________________________________________________________________________ Keywords: conservation, genetic diversity, morphological markers, RAPD (Randomly Amplified Polymorphic DNA) INTRODUCTION Pterocarpus santalinus L.f (Fabaceae), commonly named in trade as “Red sanders”, known for its medicinal and com- mercial value. It is an endangered, endemic tree species that occurs in patches in few regions of Southern Eastern Ghats and has a restricted natural range of 15,540 sq. km (Ahmed and Nayar 1984; Sarma 1993; Jadhav et al. 2001). It is a tropical dry deciduous forest species confined to 13°30- 15 o N latitude and 78°45-79°30E longitude (Kesavaraju and Jagdishwararao 1991) and it grows at an elevation of 100-1000 m above-sea level, mainly on stony or gravelly soil on formations of gneiss, quartzite, shale or laterite and loamy soils, does not tolerate stiff water logged soil, but has been planted with success on rich alluvial grounds (Troup 1921). It is a strong light demander and does not tolerate overhead shade. It is mostly an outcrossing plant species and pollination occurs with the aid of few species of bees (Apis dorsata, A. cerana var. indica and A. florae). A. dor- sata is the main pollinator and shows facultative xenogamy (Purnachandrarao and Solomanraju 2002). Commercially the plant is known for the wavy grained nature of the wood and medicinally the wood powder is used to cure various diseases i.e., as an astringent, antipyre- tic, antihelminthic, antiperiodics, diaphoretic, alexeritic and in curing freckles, defects of vision, bone fractures, leprosy, scorpion sting, mental aberrations, hemophilic disorders, in- flammation, blood purifier, skin diseases, hemicrania, etc. (Parrotta 2001). The fruit and pod decoction is used as an astringent and tonic and for curing chronic dysentery. Roots and clumps are useful for dyeing cotton, leather and stain- ing wood. Overexploitation poses a severe threat to the exis- tence of this precious timber tree (Ahmed and Nayar 1984). Hence there is a need for assessment of conserved germ- plasm for future use. Plant species especially perennials such as trees rely on the availability of genetic diversity for stability and survival under ever-changing environments (National Research Council 1991). Understanding species population genetic structure is essential for their conservation, planning and sustainable management (Sun et al. 1998). Hence, a com- mon goal of conservation is to maintain genetic diversity in threatened species, which is crucial for long-term survival and evolutionary response to the changing environment (Hueneke 1991). Plant populations may show morphological variations as an adaptation to different selection pressures (Morrison and Weston 1985; Nevo et al. 1986; Hageman and Fahselt 1990), which may result from phenotypic plasticity, genetic differentiation due to natural selection, evolutionary forces to some extent, environmental conditions, and genetic dif- ferentiation, which in turn may be due to genetic divergence or polymorphism. A phenotypic response to environmental conditions may allow a genetically non-adapted population to survive long enough to accumulate variants and then adapt genetically (Baldwin 1896; Osborn 1897). Classical methods like provenance and progeny tests coupled with biometrical analysis of phenotypic identification are not sufficient to solve these problems because of the high cost and slow techniques, instability of the morphological cha- racters i.e., clonal and environmental variability as well as an inability to use such information for identification at juvenile stages or of isolated plant parts and occurrence of lots of developmental changes (National Research Council 1991). Development of molecular markers has complemen- ted the generation of information required to making con- servation and management decisions (Virk et al. 1995). They offer several advantages over traditional phenotypic markers, as they provide data that can be analyzed objec- tively (Joshi et al. 1999). RAPD (Randomly Amplified Polymorphic DNA) is one of the techniques used for identification of duplicates, supe-