Effect of Irrigation with Saline Water on Germination, Physiology, Growth, and Yield of Durum Wheat Varieties on Silty Clay Soil

Freshwater scarcity in arid regions forces farmers to use saline water, reducing durum wheat (Triticum turgidum L. subsp. durum) productivity, particularly during early growth stages. This study evaluated two Moroccan varieties, Faraj and Nachit, 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, germination stress index, mean germination time, root and coleoptile length, plant height, leaf number, chlorophyll fluorescence, grain yield, weight of 200 grains, and straw yield. Germination percentage declined from 8 dS m−1, with delayed germination and inhibited vegetative growth at higher salinity. Both varieties maintained grain yield up to 8 dS m−1 and weight of 200 grains and straw yield up to 12 dS m−1, with Nachit showing higher tolerance. Multivariate analyses, including principal component analysis and heatmaps, linked soil sodium, chloride, and electrical conductivity negatively to growth and yield, whereas potassium, calcium, and magnesium supported plant growth and physiological activity. These findings provide insights for breeding and irrigation strategies to sustain durum wheat under salinity stress.