Genetic Analysis of Physic nut Jatropha curcas L. Populations in Thailand Using ISSR Markers Nassapat Boonvitthya 1,2 , Jittra Piapukiew 1 , Chompunuch Glinwong 1,3 and Warawut Chulalaksananukul 1,3 * 1 Department of Botany, 2 Biological Sciences Programs and 3 Biofuels by Biocatalysts Research Unit Faculty of Science, Chulalongkorn University, 254 Phayathai Road Bangkok 10330, Thailand *Corresponding author. E-mail: warawut.c@chula.ac.th Abstract-Jatropha curcas L. (Physic nut) is a drought-resistant shrub belonged to the family Euphorbiaceae. The oil from most J. curcas varieties has a low viscosity that makes it an attractive alternative energy source for biofuel production. Evaluating the degree of genetic diversity between populations and the development of genome wide markers are important for the long-term improvement of cultured varieties in any given habitat. The genetic diversity of 58 samples from 13 J. curcas populations, and one outgroup of J. gossypifolia, in Thailand were analyzed by inter-simple sequence repeat (ISSR). From 12 screened ISSR primers, two primers ((AG) 8 T and (ATG) 5 ) generated a total of 21 discrete and reliably amplified products, of which 15 were polymorphic and revealed 71.4% polymorphism among the tested J. curcas in Thailand. An UPGMA dendrogram of the Thai J. curcas samples, based on their genetic similarity using these dominant ISSR markers, divided the 13 populations into at least six main groups, with two being further divided into at least two subgroups each, which were largely incongruent with their geographical locations. It is possible that the genetic variation within J. curcas, which is widely distributed throughout Thailand since its initial introduction, is caused by human disturbance. Keywords- Jatropha curcas; ISSR; UPGMA; Genetic diversity I. INTRODUCTION The ideal feedstock for biodiesel should, therefore, be either waste vegetable oils, or else non-edible oils, the latter of which includes that from Jatropha curcas as well as Madhuca indica and Pongamia pinnata [1]. Jatropha curcas L. (Physic nut, Purging nut) is a plant belonging to the Euphorbiaceae family. Originating in Central America and the Caribbean region, it is now cultivated mainly as a hedge to protect fields in many Latin American, Asian and African countries and is known by nearly 200 names, which indicates its significance [2-3]. It is well adapted to arid and semi-arid conditions and is often used for the prevention of soil erosion [4-5]. All parts of the J. curcas plant have been used in traditional medicine and for veterinary purposes for a long time; but especially the seeds which at a 30 - 40% (v/w) oil composition and a 90% attainable extraction yields are a good source of oil. However, the fatty acid composition of this oil, namely a high percentage of monounsaturated oleic acid and polyunsaturated linoleic acid, would make it an efficient substitute for diesel fuel [6-7]. Moreover, transesterification of the oil for use in standard diesel engines is gaining more importance than direct utilization of the oil in adapted engines. Thus, J. curcas appears to be a suitable source for oil component of the production of renewable biodiesel fuel [8]. Jatropha. curcas was introduced and spread into Thailand by Portuguese merchants more than two centuries ago from an unknown foundress number and genetic stock, but is now widely grown in various regions of Thailand [9]. Depending upon the genetic, phenotypic and productive variances between local varieties of J. curcas, directed hybridization and especially marker assisted selection would be of some importance to initiate long-term breeding and selection of genotypes having a higher oil content and yield. Inter-Simple Sequence Repeat (ISSR) is genetic markers which can reflect the genetic variation between samples [10]. Like other dominant markers, such as Random Amplified Polymorphic DNA (RAPD), the ,((( 656 International Conference on Renewable Energy Research and Applications Madrid, Spain, 20-23 October 2013 ICRERA 2013 656