Effect of ZnO and TiO2 Nano-Priming on Germination, Growth and Antioxidant Activity of Capsicum chinense Jacq.

Nanotechnology has recently emerged as a promising approach for regulating plant growth and physiological processes, with nanoparticle-mediated seed treatments offering innovative strategies for agricultural improvement. Capsicum chinense Jacq. ‘Umorok’, a widely cultivated chili variety of Northeast India, holds substantial nutritional, culinary and economic value, yet its productivity is often constrained by poor germination and weak early seedling establishment. Enhancing early-stage performance is therefore critical for improving overall crop yield and resilience. In this study, the potential of nano-priming using zinc oxide (ZnO) and titanium dioxide (TiO2) nanoparticles to enhance seed performance and early growth in C. chinense ‘Umorok’ was investigated. Seeds were primed with a range of nanoparticle concentrations (ZnO: 100–400 mg/L; TiO2: 200–600 mg/L) and evaluated against an unprimed control for germination percentage, seedling vigor, photosynthetic pigment content and antioxidant activity. ZnO treatments resulted in significant improvements across all parameters up to 200 mg/L, beyond which the effects plateaued or showed a slight decline. In contrast, TiO2 treatments exhibited a clear dose-dependent enhancement, with optimal performance observed at 400 mg/L. Comparative analysis revealed that TiO2 nanoparticles were more effective than ZnO at their respective optimal concentrations, promoting superior physiological and biochemical responses. Overall, the results demonstrate that nano-priming is an effective strategy for improving early developmental traits and metabolic activity in chili plants. Among the treatments tested, TiO2 nanoparticles at 400 mg/L emerged as the most efficient, highlighting their potential application in sustainable crop production systems.