Comprehensive Evaluation of Morpho-Physiological and Ionic Traits in Wheat (Triticum aestivum L.) Genotypes under Salinity Stress

Salinity is the foremost abiotic stress that severely affects plant growth and constrains its productivity worldwide. In the present investigation, genetic variation in wheat genotypes was evaluated to identify novel salt-tolerant genetic resources, which could be used in the bread wheat improvement program. A diverse panel of 44 different wheat genotypes was evaluated at seedling stage to characterize morphological and ionic traits under salt stress (150 mM NaCl). Salt treatment caused 33.33, 45.31, 55.17, and 72.53% reduction in root dry weight (RDW), root fresh weight (RFW), shoot dry weight (SDW), and shoot fresh weight (SFW), respectively. Under salt stress, maximum inhibition of Na+ ion uptake was observed in tolerant genotypes, and this was accompanied by a high Ca2+ uptake. Wheat genotypes showed a wide spectrum of responses under salt stress; however, four genotypes, EC576356, IC533596, IC279230, and IC290188, exhibited consistent performance, which was strongly linked to proper Na+ and K+ discrimination in leaves. The tolerant genotypes acquired a better ability to maintain stable relative water content (RWC), chlorophyll (CHL), and photosynthesis rate (PS), resulting in significantly higher dry matter production under salt stress. Further, biomass, shoot K+, root Ca2+, and shoot K+/Na+ were identified as the most effective parameters for screening wheat germplasm for salinity tolerance. The identified germplasm could be used as donors for transferring salt tolerance to improved cultivars as well as in further genetic studies to uncover the genetic mechanisms governing salt stress response in wheat.