Genotype-dependent responses of wheat to salinity and phosphorus during early growth.

Wheat (Triticum aestivum L.) is a staple crop in Morocco, yet its productivity is increasingly constrained by salinity, particularly in irrigated regions, such as Tadla. Salinity stress hampers seed germination and early growth, thereby limiting crop establishment and yield. Phosphorus (P) has been recognized for its role in mitigating salt-induced damage, but its interactive effects with salinity on wheat genotypes and early growth of wheat genotypes remain insufficiently explored. This study investigated the combined influence of different salinity levels (5.7, 7.4, and 10.6 dS·m⁻¹) and phosphorus application rates (50, 100, and 150 kg P₂O₅ ha⁻¹) on germination and early growth of three wheat cultivars: “Achtar”, “Amal”, and “Kharouba”. Results showed that salinity significantly reduced all measured traits, with effects varying across cultivars. Even at moderate stress levels, germination rates declined sharply, with “Kharouba” showing the greatest sensitivity (87% re-duction under severe salinity). Phosphorus application, particularly at 100 kg P₂O₅ ha⁻¹, improved germination under high salinity, most notably in “Achtar” and “Amal.” Distinct varietal responses were observed: “Amal” exhibited the highest resilience across traits, “Achtar” was highly sensitive in root and stem elongation but responded positively to higher P application (150 kg P₂O₅ ha⁻¹), while “Kharouba” performed well under low to moderate salinity but failed at the highest stress level. Overall, phosphorus supplementation, especially at moderate rates, proved effective in enhancing early wheat growth under saline conditions, though responses were strongly genotype dependent. These findings highlight the importance of integrating cultivar selection with optimized phosphorus management to improve wheat establishment and productivity in saline irrigated soils.