Foliar and Soil Application of B, Zn, and Si Fertilizers Induce Defense Responses in Wheat Plants Against Bipolaris Leaf Blight (BpLB)

Bipolaris leaf blight of wheat is a serious biological obstacle that can be seen at any growth stage. Fertilizer management and micronutrient application have crucial roles in plant disease management. In this study, boron, zinc, and silicon fertilizer were applied in soil and sprayed on the foliage of wheat plants at the seedling, tillering, and booting stage to investigate their effect on the incidence and severity of leaf blight disease caused by <i>Bipolaris sorokiniana</i> and also evaluated the defense responses against the pathogen. Nine treatment combinations were applied in a susceptible wheat cultivar Kanchan. Vegetative parameters like the number of plants/pots, number of leaves/pots, and plant height (cm) are significantly promoted by micronutrient application at all growth stages. All combinations of micronutrient treatments expressively influenced disease parameters at 45 and 60 days after sowing (DAS) and yield contributing characters at 100 DAS. Yield components were assessed at 100 DAS. The lowest incidence and severity of leaf blight were found in <i>T</i> ₇, where 50% of the total micronutrients were applied to the soil and 0.30 g Zn and 0.30 g Si were applied on the foliage of the wheat plants. Total phenol content (401.79 μg/g), MDA (68.90 nmol/g FW), and H₂O₂ (82.36 nmol/g FW) were gradually increased after micronutrient applied and recorded highest in <i>T</i> ₇ at 21 days after treatment (DAT). Antioxidant enzymes like catalase (CAT) (2.97 mM min^-1 g^-1 FW) and ascorbate peroxidase (APX) (15.36 mM min^-1 g^-1 FW) were also found highest in <i>T</i> ₇. It is revealed that B, Zn, and Si can increase tolerance related to certain biochemical attributes, vegetative growth, and yield contributing characters of wheat.