IMPACT OF NANOSILICA ON GROWTH, PHYSIOLOGICAL PARAMETERS AND YIELD OF RICE VARIETIES CO53 AND CO54 (ORYZA SATIVA) UNDER DROUGHT CONDITIONS

. The field experiment was conducted at Department of Rice, Tamil Nadu Agricultural University, Coimbatore during 2022 with the objectives to study the effect of nano-silica emulsion on growth, physiological parameters and yield of rice varieties CO53 and CO54 under drought stress. Nanosilica emulsion was prepared from pure nanosilica and it was mixed with tween 80 and water (1:3). Then solution was subjected to sonication at 50% amplification for 30 min with 10:10 plus rate. Based on the requirement of experiment, different concentrations of the nanosilica concentrations were used as foliar spray viz., 200, 400, 600, 800 and 1000 ppm under drought stress. The drought was imposed by withholding of irrigation for all treatments except T 1 (Irrigated) from 12 days before flowering and 10 days after flowering. The total period of the stress was 22 days. The irrigation was controlled by bund and the water leakage was vetoed by placing of plastic sheets. The water drained out by buffer channels in drought imposed plots. The application of 400 ppm nanosilica formulation resulted in the tallest plants and highest leaf area index, with a 16.4% increase over the control, while the CO54 variety showed the most response with a maximum increase of 18.8% in plant height and 17.9% in leaf area index under drought stress. The application of nanosilica as foliar spray at 50% flowering stage (mid of the drought period). The application of 400 ppm nanosilica formulation expressed more response in morphological (17-21%), physiological (22-35%) and yield parameters (16-30%) in CO53 and CO 54 varieties over control under drought stress. The application of nanosilica @ 400 ppm as foliar spray at 50% flowering stage is highly suitable to mitigate the drought stress in rice.