Genetic diversity based on osmotic stress tolerance-related morpho-physiological traits and molecular markers in traditional rice cultivars

Abstract

Osmotic stress is one of the major global constraints for the rice cultivation, especially in the rainfed cropping system practiced in Assam, India. Hence, exploration of the discrepancy in functional along with germplasm structure among the traditional rice cultivars is needed. Morpho-physiological traits induced by osmotic and inter simple sequence repeat (ISSR) markers were considered to survey genetic array in growth chamber trials. Twenty one traditional rice cultivars from different agro-climatic regions of Assam, previously used in our laboratory were used in this study along with Sahbhagi and IR64 as control that revealed a high differentiation in phenotypic performance under osmotic stress. On the basis of standardized osmotic tolerant related morpho-physiological parameters, all the rice cultivars could be assembled into five clusters. The cultivars included in a single group revealed almost identical osmotic tolerance levels. The rice cultivars from different agroclimatic zone viz., upper Brahmaputra valley, lower Brahmaputra valley and hill Zones revealed highest genetic diversity as judged by Jaccard coefficient matrix with polymorphism information content (PIC) 0.30. Furthermore, rice cultivars were observed to be constituted into five major clusters depending on ISSR markers that were relatively congruous to the agro climatic regions and specific traditional cultivation practices. The mantel test of the rice varieties between morpho-physiological and ISSR markers exhibited low correlation. The variation observed in morpho-physiological traits associated with genetic diversity has paved a potentiality to design osmotic stress resistant varieties in future breeding programme.