Unravelling wheat genotypic responses: insights into salinity stress tolerance in relation to oxidative stress, antioxidant mechanisms, osmolyte accumulation and grain quality parameters.

Abstract

Background: Salt stress is a prominent abiotic stressor that imposes constraints on grain yield and quality across various crops, including wheat (Triticum aestivum). This study focused on assessing the genetic diversity of 20 wheat genotypes categorized as tolerant, moderately tolerant, and sensitive with three genotypes of unknown tolerance. To address salinity stress-related problems, different morpho-physiological, osmoprotectant, biochemical, yield, and grain quality-related parameters were analyzed under control (pH 8.0, EC 3.9) and saline-sodic (pH 9.4, EC 4.02) conditions in field.

Results: Findings revealed noteworthy variations among the genotypes in response to salinity stress. Greater accumulation of Na⁺ and lower K⁺ content were observed in response to salt stress in the sensitive varieties HD1941 and K9162. Proline, a stress indicator, exhibited significantly (p ≤ 0.05) greater accumulation in response to salinity stress, particularly in the tolerant cultivars KRL210 and KH65. Salt stress induced the most significant decrease (p ≤ 0.05) in spike length, thousand-grain weight, and hectolitre weight coupled with increased protein content in sensitive varieties, resulting in diminished yield.

Conclusion: Correlation analysis of parameters under salinity stress showed that SOD, proline, and K⁺ contents can be used as the most efficient screening criteria for salinity stress during early developmental stages. Principal component analysis revealed that DBW187, DBW303, and DBW222 varieties were tolerant to salinity stress and exhibited an effective antioxidant system against salinity. This study will facilitate salt-tolerant wheat breeding in terms of the identification of tolerant lines by screening for limited traits in a wide range of germplasms.