Molecular characterization of rice (Oryza sativa L.) genotypes for drought tolerance using two SSR markers

Abstract

Plant growth as well as productivity of rice (Oryza sativa L.), the major cereal and staple food of millions, is significantly affected by numerous biotic and abiotic stresses. Among these, drought stress is one of the major constraints for production and yield stability of rice in rainfed ecosystem. Hence rice varieties/genotypes with drought tolerance must be identified urgently. The main objectives of the present study were screening of seedlings of various rice genotypes for drought tolerance by conventional method and molecular characterisation of selected rice genotypes for drought tolerance using microsatellite markers. Twenty one rice genotypes obtained from the Plant Breeding Division, RARS, Pattambi, were used for the study. Initially, seedlings of these genotypes were subjected to conventional drought screening with PEG-6000 (6 MPa and 8 MPa). Out of the 21 rice genotypes, only fourteen genotypes were selected based on seedling vigour index and used for molecular characterisation. DNA extraction of samples was performed by CTAB method followed by PCR amplification with two specific SSR markers, viz., RM103 and RM212. Monomorphic bands were observed with RM103 for all the fourteen genotypes; hence it cannot be considered as a suitable marker for drought tolerance in these genotypes. Polymorphic bands were observed in the studied genotypes for the marker RM212. However, linkage between RM212 marker with the seedling vigour index under drought stress was not significant. Hence, further research with other linked SSR markers must be carried out for marker assisted selection for drought tolerance in these rice genotypes.