Association and Genetic Variability Studies for Reproductive Stage Salinity Tolerance Traits in Rice (Oryza sativa L.)

Abstract

Salinity is the second major abiotic stress which significantly affect the rice crop particularly at reproductive stage. Understanding the genetic variability and trait relationship in terms of direct and indirect effects is important to strength the breeding programme to develop salt tolerant rice varieties. Hence, a study was carried out in rice to evaluate 204 F3:4 (MTU 1061 × MTU 1121) progenies along with two parents and checks during kharif 2021 and rabi 2021-22. In this study, highest positive direct effects were observed for the traits number of total grains/panicle (0.4536, 0.4499), panicle length (0.1015, 0.0994), productive tillers per plant (0.1008, 0.0974) and spikelet fertility (0.0913, 0.0953) at genotypic and phenotypic levels. High PCV and GCV was observed for spikelet fertility, number of filled grains/panicle, number of total grains/panicle and grain yield/plant. The traits panicle length (64.28%), flag leaf length (74.34%), plant height (80.34%), productive tillers per plant (94.94%), number of filled grains/panicle (99.66%) and number of total grains/panicle (99.99%) displayed high heritability values. Higher genetic advance over mean (GAM) was observed for spikelet fertility, number of filled grains/panicle, productive tillers per plant and number of total grains/panicle. High GAM and heritability were observed for the traits number of filled grains/ panicle, number of total grains/panicle, productive tillers per plant and spikelet fertility. Thus, these traits should be prioritized while selecting rice lines for increasing yield under salt stress conditions as they have moderate to high PCV, GCV, heritability and genetic advance over mean.