Synergistics effect of novel nano biochar on wheat growth, yield and antifungal response under cadmium contaminated soil: A field study

Agricultural productivity is seriously threatened by environmental stresses, including both biotic and abiotic factors. The consumption of wheat (Triticum aestivum) as a staple crop is associated with increased risks to human health due to contamination with cadmium (Cd) and fungal infections caused by Ustilago tritici. The current study investigates the influence of the cerium oxide nanoparticles (CeO₂ NPs) combined with wheat husk biochar (BC) on T. aestivum for the antifungal activity cultivated on cadmium (Cd) contaminated soil. To determine the efficacy of CeO₂ NPs alone and in combination with BC against the fungal attack of Ustilago tritici under the cadmium (Cd)-contaminated soil, which harms wheat crop yields worldwide. The investigation was carried out during the wheat growing season, using T. aestivum grown in the natural field condition. Cerium oxide NPs were foliar sprayed twice on wheat plants at three given levels: NPs 0 (0 mg L^-1), NPs 50 (50 mg L^-1), and NPs 100 (100 mg L^-1), with BC used at 0 %, 0.5 %, 1.0 %, and 1.5 %, respectively, into the soil before seed sowing. The results of the current study indicated that 1.5 % BC along with 100 mg L^-1 CeO₂ NPs had a synergistic effect on wheat growth, increasing the height from 98 cm to 140 cm along with an increase in spike length from 8 cm to 18 cm and achieving a combined grain and straw yield of 8 tons ha^-1. There was a remarkable increase in photosynthetic rate (7.4), transpiration rate (1.5), and stomatal conductance (1.4) together with an increase in chlorophyll a (2.5 mg g^-1 FW) and chlorophyll b (2.65 mg g^-1 FW) contents. The activities of antioxidants such as superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase increased whereas the advanced oxidative stress markers electrolyte leakage (EL), malondialdehyde (MDA), and hydrogen peroxide (H₂O₂) levels dropped substantially. Moreover, the disease severity index was reduced from 75 % logged in the control to as low as 28 % for the combined treatment, portraying an increase in resistance to stress. Hence, this combined treatment has strong anti-fungal potential on U. tritici under the Cd-contaminated conditions, making it a promising technique for mitigating environmental illnesses and agricultural losses throughout the world.