Sodium Exclusion Affects Seed Yield and Physiological Traits of Wheat Genotypes Grown Under Salt Stress

Increasing salinization is a real threat to food security by diminishing the performance of glycophyte staple crop wheat. To tackle salinity, one option is to identify and use salt-tolerant germplasm but salinity tolerance is a multigenic trait which is conferred by a large array of interacting physiological and biochemical processes. Keeping this in mind, (eighteen) physiological indices were used to appraise salt tolerance of 20 bread wheat genotypes and specifically evaluated the effect of sodium exclusion on seed yield of salt-stressed wheat genotypes in pots. Significant statistical difference was found between the genotypes, at different salinity levels for physiological, biochemical, and yield-related attributes. Under salt regime (15 dS m−1), the performance of all wheat genotypes was significantly affected as compared with those of the plants grown in control conditions (1.41 dS m−1). Among the 20 genotypes, Kharchia 65 produced maximum grain yield followed by V-03094, V-02156, LU26S, PVN, V0005, and TURACO, which was linked to lower Na+ and higher K+ accumulation in the leaf. Moreover, these genotypes also maintained higher K+/Na+ ratios in their leaves under saline stress. Furthermore, significant increase in leaf proline content was found in all genotypes growing in salt regimes as compared with those in plants grown under non-saline conditions. Chlorophyll fluorescence such as non-photochemical chlorophyll fluorescence quenching (NPQ) and electron transport rate (ETR) were markedly higher in saline environment in all wheat genotypes as compared with those in plants grown in control. Of the 20 genotypes, V-0005 followed by V-02156, V-03094, V-04181, and PVN were found to be salt-tolerant as they showed enhanced exclusion of Na+ and maintained the high K+/Na+ ratio. These genotypes also showed improved plant water relations and gas exchange characteristics and less cell membrane injury. While genotypes PBW343*2, PUNJAB 85, FRET2, and TAM200/TUI were found to be salt-sensitive genotypes. Better yield was strongly linked with sodium exclusion, stable membranes, and protected oxygen-evolving complex (PS II).