Effect of zinc oxide nanoparticles and inoculation with arbuscular mycorrhizal fungi on growth, yield, and antioxidant capacity of Capsicum chinense Jacq. (Habanero pepper)

The use of zinc oxide nanoparticles (ZnO NPs) is part of the search for strategies to achieve food security in a sustainable way. However, its usefulness in crop production has not been sufficiently demonstrated and its consequences on soil microorganisms are still unclear. In this study, the combined effect of ZnO NPs and inoculation with arbuscular mycorrhizal fungi (AMF) on growth, yield, and antioxidant capacity of Capsicum chinense Jacq. was analyzed. Additionally, the effect of ZnO NPs on mycorrhizal colonization and dependency was evaluated. For this purpose, a greenhouse experiment was performed in which 0, 1.2, 12, and 240 mg kg⁻¹ of ZnO NPs were applied to mycorrhized and non-mycorrhized plants. Fresh and dry biomass, fruit yield, and antioxidant capacity were quantified, as well as colonization percentage and mycorrhizal dependency. It was found that the ZnO NPs 240 mg kg⁻¹ dose increased plant fresh aerial biomass and antioxidant capacity, while all ZnO NPs doses increased fruit biomass. On the other hand, the 12 and 240 mg kg⁻¹ doses decreased mycorrhizal dependency, but no ZnO NPs dose affected mycorrhizal colonization. In turn, the inoculation with AMF increased all growth and fruit yield variables, but not the antioxidant capacity of habanero pepper. Besides, an antagonistic effect on fruit biomass was found between the addition of ZnO NPs and the inoculation with AMF. These results demonstrate that the application of ZnO NPs within the dosage range of 1.2 to 240 mg kg⁻¹ enhances the yield of C. chinense without impacting its mycorrhizal interaction.