Journal of Applied Sciences Research, 3(12): 1933-1935, 2007 © 2007, INSInet Publication Corresponding Author: B. Senthamizh Selvi, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore – 641 003, Tamil Nadu, India. E-mail: selvi 215@yahoo.com 1933 Identification of DNA Polymorphism induced by Gamma Ray Irradiation in Amla 1 1 2 1 (Emblica Officinalis Gaertn.) Grafts of V M and V M Generation B. Senthamizh Selvi, V. Ponnuswami and T. Sumathi Faculty of Horticulture, Horticulral College and Research Institute, Tamil Nadu Agricultural University, Coimbatore – 641003, Tamil Nadu, India. Abstract: Considering the limits of the use of morphological markers, the reliable estimate of identifying DNA polymorphism in amla mutants induced by gamma rays was assessed using RAPD markers. A total of 110 amplified fragments were obtained with seven RAPD primers across the twenty one amla mutants. Appearance and disappearance of new bands can be explained as the result of DNA structural changes (breaks, transpositions, deletions, etc.). due to gamma ray irradiation. Keywords: Gamma irradiation, Emblica officinalis, molecular markers, breeding, APD INTRODUCTION Amla or Indian gooseberry ( Emblica officinalis Gaertn ) of the family Euphorbiaceae is known for its medicinal and therapeutic properties from the ancient time in India and considered as a wonder fruit for health conscious population. Owing to its hardy nature, ability to survive in various kinds of waste lands (arid, semi-arid, salt affected, coastal ravines), high productivity per unit area, nutritive and therapeutic values and suitability for various products viz., food items, cosmetics and ayurvedic medicinal preparations, amla is becoming an important fruit of 21 century. st Amla is not only a source of nutrients and medicine, but cultivation of the crop is also highly remunerative for the farmers having marginal land. Traditionally, amla has been a crop of forest or household, but during the last decade, there has been unprecedented expansion in the area under amla cultivation across the country, utilizing the wasteland. This has resulted in efficient utilization of resources leading to better income to farmers, nutritional security coupled with enhanced employment and rehabilitation of wastelands. Continued vegetative propagation employed in the commercial varieties has led to less variability of desirable traits except for size. In this context, induction of mutation is an important breeding tool to improve the desirable characters among the existing commercial varieties. Thus, amla crop can be considered as a suitable crop for the application of mutation breeding methods and in subsequent selection of desired genotypes. Similarly, the use of radiation as a mutagen for inducing variation is well established. Although the desired variation is often lacking, radiation can be used to induce mutations and thereby generate genetic variation from which desired mutants may be selected. Different methods are available to investigate the effect of mutagens on plants. However, molecular markers allow a direct comparison of the effects of genotypes at the DNA level. The explorations of random amplified polymorphic DNA (RAPD) as genetic markers have improved the effectiveness of recombinant DNA techniques. RAPD analysis is widely used for the genetic mapping, taxonomic and phylogenetic studies of organs and hence can be used for the detection of DNA alterations after the influence of mutagenic agents. Irradiation by gamma rays leads to the increasing level of DNA break formation. These different types of DNA damages must be detected by changes in RAPD profiles. Thus, the present study on 1 1 mutation induction in amla var BSR -1 of V M and 2 1 VM was undertaken to identify the DNA polymorphism induced by gamma rays. MATERIALS AND METHODS Mutagens: A physical mutagen (Gamma rays) was employed in the present study. Gamma rays treatment was given from the Gamma chamber – 900 installed at Tamil Nadu Agricultural University, Coimbatore. Gamma ray source was Co in 1000 curie, emitting 60 5000 rads per minute at the time of irradiation. Irradiation: The amla scions with dormant buds were treated with gamma rays. The scions of pencil thickness consisting of 10 nodes (dormant buds) from seven year old mother trees were collected and treated