Agricultural areas worldwide suffer immensely due to the rapid depletion of irrigation water. Applying the proper nutrients can alleviate the harmful effects of water stress. This field study transpired to evaluate the influence of both titanium-dioxide (TiO₂) and zinc-oxide (ZnO) nanoparticles on two wheat (Triticum aestivum L.) cultivars (Gimeza-12 and Sids-13) under water irrigation requirements (WIR) of 100% and 75% WIR. Water stress reduced yield attributes and mineral contents but increased protein, gluten, Zeleny sedimentation index, flavonoids, antioxidant activities, and WP. All used concentrations of TiO₂-NPs and ZnO-NPs induced positive responses for all tested parameters compared with non-treated corresponding controls under well-watered and drought-stress conditions. Treatment with 10 mg L^-1 of ZnO-NPs followed by 10 mg L^-1 TiO₂-NPs gave the highest values of all studied yield parameters in plants subjected to 75% WIR for both cultivars compared to other controls. The results showed that the Gimeza-12 cultivar, which had the highest grain yield, was more tolerant to drought than the Sids-13 cultivar.

Keywords: Wheat (Triticum aestivum L.), water stress condition, nanoparticles, grain yield, biochemical composition, nutritional values

Key findings: All used concentrations of TiO₂ and ZnO-NPs induced positive responses for all tested parameters compared with non-treated corresponding controls under well-watered or drought-stress conditions in wheat (T. aestivum L.). Treatment with 10 mg L^-1 of ZnO-NPs followed by 10 mg L^-1 TiO2-NPs resulted in higher yield parameters in plants under 75% WIR for both cultivars than the control. The Gimeza-12 cultivar was more tolerant to water stress than the Sids-13 cultivar, which produced excellent grain yield.