Zinc Oxide Nanoparticles and Biochar Enhance Wheat Resilience to Salinity through Biochemical and Yield Traits

Salinity stress significantly constrains global wheat (Triticum aestivum L.) production, necessitating novel amelioration strategies. This experiment investigated the biochemical and yield responses of 11 diverse wheat genotypes to salinity stress, and the mitigating effects of foliar-applied zinc oxide nanoparticles (ZnONP) and soil-incorporated biochar (BC). A randomized complete block design with three replications was employed. ANOVA revealed highly significant differences (p≤0.001) among genotypes, treatments, and their interactions for all assessed traits. Salinity significantly reduced thousand grain weight (TGW) from a control average of 24.49 g to 18.51 g, and grain yield per plant (GYP) from 34.96 g to 26.02 g. Conversely, proline content increased from 23.06 μg/g FW under control conditions to 82.28 μg/g FW under salinity stress. Both ZnONP and BC treatments partially restored TGW (22.60 g and 22.70 g, respectively) and GYP (31.96 g and 33.04 g, respectively), with BC demonstrating slightly superior efficacy for GYP. Zn contents in grains was markedly enhanced by ZnONP (212.92 mg/kg) and BC (216.93 mg/kg) compared to control (72.77 mg/kg) and salinity (52.81 mg/kg). Antioxidant enzyme activities, including glutathione reductase (GR) and superoxide dismutase (SOD), generally increased under stress and were further augmented by amendments. GR activity was highest with BC (17.34 EU/mg), while SOD peaked under ZnONP (62.98 EU/mg). Genotypes G10 and G9 consistently exhibited superior performance across most ameliorative treatments. These findings underscore the potential of ZnONPs and biochar as sustainable solutions for enhancing wheat productivity under saline conditions, particularly when integrated with tolerant genotypes.