Comparative assessment of saline irrigation effects on germination, physiological responses, growth, and yield of durum wheat varieties grown on silty clay soil

Freshwater scarcity in arid and semi-arid regions forces farmers to rely on saline irrigation, challenging crop productivity and sustainability. Durum wheat, a staple cereal crucial for food security, is highly sensitive to salinity, particularly during early growth. This study compared responses of two local Moroccan durum wheat varieties, Faraj and Nachit, grown on silty-clay soil under five salinity levels (0.2, 4, 8, 12, and 16 dS m⁻¹) in a randomized complete block design with three replications, aiming to identify tolerance thresholds and characterize physiological and agronomic responses. Key traits measured included germination percentage (PG), germination stress index (GSI), mean germination time (TMG), root length (RL), coleoptile length (CL), plant height, number of leaves, chlorophyll fluorescence (ChlF, Fv/Fm), grain yield (GY), 200-grain weight (200-GW), and straw yield (SY). Results showed PG declined markedly from 8 dS m⁻¹, with ISG decreasing and TMG increasing, indicating delayed germination. Vegetative growth was inhibited with higher salinity, affecting RL, CL, plant height, number of leaves, and ChlF. Both varieties maintained GY up to 8 dS m⁻¹ and SY, 200-GW up to 12 dS m⁻¹, with Nachit exhibiting superior resilience. At 16 dS m⁻¹, yield components declined sharply. Multivariate analyses (PCA and heatmaps) revealed strong correlations between electrical conductivity, Na, and Cl with reduced growth and yield, while K, Ca, and Mg correlated positively with vigor and productivity. These findings highlight the comparative performance of Faraj and Nachit and support their use in breeding programs and irrigation strategies to sustain durum wheat production under saline conditions.