Evaluation of yield-related physiological and biochemical traits in recombinant inbred lines of bread wheat under sodic stress

Salt stress is one of the major constraints plaguing the global agriculture sector, severely undermining food and nutritional security. Accelerated soil salinization driven by climate change and rising temperatures has increasingly affected wheat productivity and grain quality. In the present study, the impact of sodic stress on yield-related and biochemical traits was evaluated in a population of recombinant inbred lines (RILs) derived from a cross between a salt-tolerant cultivar (KH 65) and a salt-sensitive cultivar (HD 2009). The tolerant parent, KH 65, has been widely utilized in breeding programs worldwide for developing salt-tolerant wheat varieties. Under sodic conditions, the sensitive cultivar HD 2009 cultivar exhibited a markedly higher grain yield reduction (44.19%) compared to KH 65 (10.81%). The estimated heritability (h 2 ) values ranged from 0.52 for potassium (K + ) content to 0.95 for days to anthesis (DTA), indicating a broad spectrum of genetic control among the evaluated traits. Grain yield (GY) trait showed significant positive genotypic correlations (p < 0.01) with thousand-grain weight (TGW), tiller number (TN), number of ears (NE), ear length (LE), plant height (PH), proline content, and potassium (K + ) content, while exhibiting a significant negative correlation with sodium (Na + ) content. Biochemical parameters were assessed in the flag leaf, while yield-related traits were measured at maturity. Multiple regression analysis revealed that proline and K + content accounted for 58.5% and 38.1% of the total variability in grain yield, respectively (multiple R = 0.46). The key contributors to grain yield under sodic stress followed the order: proline > K + > K + /Na + ratio > NE. Principal component and cluster analyses further identified K + content, K + /Na + ratio, and proline content as major determinants of yield performance under sodic stress. Their strong positive association with grain yield, coupled with high heritability, underscores their potential as reliable selection criteria for breeding salt-tolerant wheat cultivars.