Study of salinity tolerance in selected rice genotypes at early seedlings stage using hydroponics

Abstract

A laboratory experiment was conducted in 2023 at the Department of Crop Physiology, College of Agriculture, University of Agricultural Sciences, Raichur, to evaluate salinity tolerance at the seedling stage in rice (Oryza sativa L.). The study site is located in the North Eastern Dry Zone (Zone-2) of Karnataka at 16°15′ N latitude, 77°20′ E longitude, and an elevation of 389 meters above mean sea level. Thirty-six rice genotypes were evaluated under two salinity levels 6 dSm⁻¹ and 12 dSm⁻¹ to assess seedling stage salt tolerance using the Standard Evaluation System (SES) for rice.Significant genotypic variation was observed for salt injury scores at both salinity levels. At 6 dSm⁻¹ and 12 dSm⁻¹, nine genotypes recorded a salt injury score of “1” (highly tolerant), while eight genotypes recorded a score of “3” (tolerant). The remaining nineteen genotypes scored “5”, “7”, or “9”, and were classified as moderately tolerant, susceptible, or highly susceptible, respectively. Based on SES scores, genotypes IET 28608, CSR23, FL478, GNV 1801, GNV 1109, CSR22, CSR10, SIRI 1253, and GNV 1806 exhibited high tolerance to salinity at both levels. These genotypes showed superior performance in key physiological traits such as seedling vigor, shoot length, root length, and overall seedling biomass important indicators of early growth potential under saline conditions. The study highlights the existence of considerable genetic variability for salinity tolerance at the seedling stage and identifies promising genotypes for further evaluation and use in breeding programs targeting salt-affected environments.