Correlation studies in seedling and reproductive stage salinity tolerance in rice (Oryza sativa L.) under salinity

Salinity is a major abiotic stress limiting rice productivity worldwide. The present study had 234 F2:3 population of a salt-tolerant donor Indra (MTU 1061) in the genetic background of Sri Druthi (MTU 1121) to elucidate the genetic basis of seedling and reproductive stage salinity tolerance. The F2:3 population were evaluated under salt stress at seedling stage (EC 6 &12 dSm-1) and reproductive stage (EC 6 & 12 dSm-1). At seedling stage, salt injury score had positive significant correlation with shoot Na+ concentration and Na/K ratio while it was negative & significant with K+ concentration, shoot length, root length and shoot dry weight. This indicated that homeostasis between Na+ and K+, plays a key role in the seedling stage tolerance to salt stress. In reproductive stage grain yield per plant play pivotal role for salinity tolerance comparative to remaining parameters such as number of spikelets, filled spikelets and unfilled spikelets. Results showed positive significant correlation of grain yield with days to flowering, number of total grains and productive tillers while it was negative significant with panicle length. The results of this study confirmed that salinity tolerance at the seedling and reproductive stages are independent to each other.