Nanoformulations of auxin and zeatin: A sustainable approach to minimize flower shedding in greengram

Greengram is a protein-rich pulse crop, facing significant yield challenges due to flower shedding, caused by factors such as limited photosynthesis, hormonal imbalances, genetic traits, etc. The study aimed to develop and evaluate nanoemulsions of 1-Naphthalene acetic acid (NAA) and zeatin to reduce flower shedding and improve crop productivity. Laboratory synthesis and characterization were conducted at the Centre for Agricultural Nanotechnology and a field trial was carried out at the Agricultural Research Station, Bhavanisagar. Nanoemulsions were standardized using 50% ethanol as the aqueous phase for NAA and 0.25% DMSO for zeatin, with liquid paraffin and Tween 80 forming the oil phase. The resultant formulations achieved reduced particle sizes (80-300 nm) with higher stability. Field experiments consisted of foliar application of nanoemulsions at varying concentrations and conventional formulations at recommended doses, applied at 50% flowering and 10 days thereafter. The results demonstrated that NAA nanoemulsion at 30 ppm significantly enhanced leaf area, dry matter production and chlorophyll index. Flower shedding was reduced to 60.2%, compared to control, while pod setting improved by 47.5%. The higher seed yield (1096 kg ha-1) and haulm yield were recorded with NAA nanoemulsion at 30 ppm, showing a 30.8% increase over the control. Conventional zeatin at 5 ppm also performed well but was less effective than NAA nanoemulsion. The study concluded that NAA nanoemulsion at 30 ppm effectively reduces flower shedding and enhances greengram productivity, offering a viable solution for improving sustainable crop management.