Assessment of genetic diversity of grape mutants based on RAPD and SSR markers

Abstract

The present investigation was undertaken to assess the genetic diversity in gamma rays irradiated mutants of four grape genotypes based on RAPD and SSR markers. There were 36 mutants selected from in vitro mutated four grape genotypes, namely Pusa Navrang, H-76-1, Pearl of Csaba and Julesky Muscat on the basis of morpho-physiological and biochemical traits. These mutants and non-irradiated individuals were subjected to RAPD and SSR marker analysis to detect the genetic variation amongst them. Six RAPD and eleven SSR primers were employed for PCR amplification and total 63 distinct and easily scoreable bands were generated which ranged between 110 (SSR) and 2500 (RAPD) bp. All the bands were found to be polymorphic in nature and identified 13 solid mutants, among the initially selected 36 putative mutants. The distribution of mutants by cluster analysis suggested existence of high degree of difference at the genetic level in the mutants and non-irradiated control individuals. The mutants were largely grouped into the four major clusters based on the doses of gamma irradiation except some mutants from Julesky Muscat and Pearl of Csaba genotypes. Minimum similarity coefficient (0.37) was noted in mutants of Pusa Navrang and maximum (0.70) in Hybrid-76-1. Unique banding patterns were amplified by both the types of markers (RAPD and SSR). It was suggested that Julesky Muscat was amplified uniquely by RAPD-OPA01, OPP02, SSR-VVMD14, VMCIB11, VMC8G9 primers, H-76-1 by RAPD- OPA01 and SSR- VVMD 14 primers, Pusa Navrang by RAPD-OPP02 and SSR-VVMD-21 primers and Pearl of Csaba by RAPD-OPA01, OPP04, SSR-VMC8G9 primers. The result from this study suggests that OPA01 (RAPD) and VVMD14 (SSR) were the most informative primers and generated maximum numbers of reproducible bands. The combination of these primers will be very useful for the identification of solid mutants which could be evaluated in the field.