Comprehensive screening and evaluation of diverse Mediterranean barley genotypes for salt tolerance using multiple agro-morphological and tolerance indices criteria

Salinity tolerance in barley is essential for food security and as a model for crop resilience to climate change. Twenty-three barley genotypes were evaluated under non-saline (0 dS/m) and saline (12 dS/m) irrigation regimes. To evaluate the salinity resilience of various barley genotypes, grain yield was assessed under both salinity treatment. Eight tolerance indices were calculated to comprehensively characterize performance: Salinity Susceptibility Index (SSI), Tolerance Index (TOL), Stress Tolerance Index (STI), Harmonic Mean Productivity (HMP), Geometric Mean (GM), Geometric Mean Productivity (GMP), Yield Stability Index (YSI), and Mean Productivity (MP). Analysis of variance showed genotype variation and showed that salinity had a considerable impact on agro-morphological parameters. Grain yield shown significant correlations with GMP, STI, MP, and HMP in non-stress situations, indicating that these measurements correctly estimate high performance. Principal component analysis (PCA) and heatmap visualization identified four genotypes ‘Assiya’, ‘Laanaceur’, ‘Tombari’, and ‘Giza130’ as top performers under non-saline irrigation, displaying elevated values across these indices. Under saline stress (Ys), grain yield correlated positively with Yield Index (YI), YSI, and GM, highlighting their relevance for stress resilience. Three genotypes ‘Massine’, ‘Tozeur’, and ‘Giza125’ exhibited the highest yields and index scores under salinity, suggesting superior tolerance. In contrast, ‘Manal’, ‘Amira’, ‘Elarich’, ‘Rihane’, and ‘Temellalet’ were more sensitive to salt stress. Overall, STI, MP, HMP, and GMP demonstrated consistent, significant positive associations with grain yield across both irrigation treatments, underscoring their utility as robust selection criteria. These findings support using these indices in breeding programs targeting Mediterranean barley genotypes with enhanced salinity tolerance.