Screening for salinity stress tolerance in rice and finger millet genotypes using shoot Na+/K+ ratio and leaf carbohydrate contents as key physiological traits

Abstract

A study was conducted to find out the genetic variation for salinity tolerance in rice and finger millet genotypes. Twenty finger millet and sixteen rice genotypes were screened for their tolerance/susceptibility against salinity under hydroponics in greenhouse conditions. Screening resulted in the identification of contrasting genotypes in both the crops. Among the rice genotypes, IR 29 was found to be susceptible and FL 478 was found to be tolerant to salinity stress. Among the finger millet genotypes, CO 12 was susceptible and Trichy 1 was tolerant to salinity stress. Two genotypes showing contrasting behavior to salt stress were analyzed for their shoot Na+ to K+ ratio and leaf carbohydrate contents to understand the physiological basis of salinity tolerance. In rice and finger millet, the shoot Na+/K+ ratio was found to be significantly lower, and the carbohydrate contents were much higher in the tolerant FL 478 and Trichy 1 relative to IR29 and CO 12 upon salinity treatment. Lower shoot Na+/K+ ratio coupled with higher carbohydrate contents could serve as indices to screen genotypes tolerant to salinity stresses.