Foliar Selenium Application Enhances Wheat Resistance to Bipolaris sorokiniana-Induced Spot Blotch via Modulation of Growth, Physiological Homeostasis, and Antioxidant Defense Systems

Spot blotch has become a major devastating disease in wheat. In the current study, Faisalabad-08 was supplemented with various levels of selenium (Se) both in vitro and in greenhouse experiments (CRD, n = 3) to counter the spot blotch pathogen. The results revealed that minimum disease incidence was assessed in the case of T2 (50 mg L−1). However, maximum plant growth attributes, including plant height (PH), plant fresh weight (PFW), plant dry weight (PDW), leaf surface area (LSA), and root length (RL), were recorded in T5 (50 mg L−1 + pathogen). Similarly, chlorophyll a, chlorophyll b, total chlorophyll, membrane stability index, carotenoid, relative water contents, proline, sugar, flavonoid, total phenolic content, SOD, POD, CAT, PPO, and PAL contents were enhanced in T5 compared to other tested treatments. However, MDA, an oxidative damage marker, was significantly decreased with T5. Correlation, PCA, and heatmap analysis suggested that all the attributes were significantly interrelated, except MDA, in defining the crop’s potential to sustain its growth under biotic stress. In crux, foliar Se application (50 mg L−1) effectively mitigates spot blotch through enhanced antioxidant defense and physiological homeostasis. This sustainable approach offers a viable alternative to conventional fungicides for integrated wheat disease management.