Foliar application of nano-nutrients on the structural, photosynthetic traits and yield of Psidium guajava L.

Background: A field experiment was conducted to study the effects of nano-macro and micronutrient formulations on growth, flowering, physiological attributes and yield of guava (Psidium guajava L.) var. Arka Kiran. Method: The experiment utilized a Randomized Block Design featuring ten treatments, which included different quantities of zinc oxide (ZnO), boron trioxide (B₂O₃), calcium oxide (CaO), and magnesium oxide (MgO) nanoparticles foliar spray have been given to the guava (Psidium guajava L.) var. Arka Kiran. Results: Demonstrated that ZnO nanoparticles at 1000 ppm (T4) significantly enhanced on different stages of plant height (2.26 and 2.43 m), canopy spread (1.98 m NS 1.76 m EW and 1.91 m NS 1.92 m EW) during fruit development and harvesting stage, (23.89) days taken for flower initiation, (12.68) days taken from flowering to fruit set, (122.36) days taken from fruit set to maturity, (205.24) flowers per tree and chlorophyll on different stages (31.88, 43.43, 59.53 and 53.36) fruit set per cent (72.10) fruit retention per cent (48.98) number of fruits per tree (72.50) and estimated yield per tree (12.82) compared to other treatments and control. Conclusion: The findings confirm the potential of nano-nutrient formulations, particularly ZnO nanoparticles in improving guava morphological characteristics, flowering characteristics and physiological health. These results provide a foundation for optimized nutrient management strategies in guava cultivation, promoting sustainable agricultural practices and enhancing productivity.