Effect of Moisture Stress and Growth Regulating Compounds on Root Traits, Nutrient Uptake and Yield of Transplanted Rice at Critical Stages

Background: The field experiment was conducted in the Wetland farm, SRM College of Agricultural Sciences, Baburayanpettai during the Sornavari (Apri-Aug) season of 2024 to assess the impact of growth regulating compounds on root traits, nutrient uptake and yield of transplanted rice under induced moisture stress conditions. Methods: A Field experiment was laid out in split-plot design with three replications. The treatments comprise of induced moisture stress in different crop growth stages, viz., Moisture stress free control (conventional irrigation), where the field was irrigated with 5 cm depth of water one day after the disappearance of previously ponded water (M1), Moisture stress at panicle initiation stage (M2) and Moisture stress at the flowering stage (M3) in main plots and foliar application of growth regulating compounds in sub-plots viz., Potassium silicate @ 1% (S2), Seaweed extract @ 2% (S3), Brassinolide @ 0.04% (S4) and Control without foliar application of growth regulating compounds (S1). Observations were recorded on root parameters such as root length, root volume, root dry weight and root/shoot ratio, nutrient uptake by crop (N, P and K), yield attributes (number of productive tillers m-2, panicle length, number of grains panicle-1, fertility percentage and thousand grain weight) and yield of rice under induced moisture stress. Result: Root parameters were significantly increased under moisture stress at panicle initiation stage with foliar application of one per cent potassium silicate. The treatment combination of moisture stress free control (conventional irrigation) in conjunction with foliar spraying of one per cent potassium silicate recorded higher N, P and K uptake, yield attributes and yield of rice. The critical stages of rice viz., panicle initiation and flowering, are most sensitive to moisture stress and can create yield reduction. Especially moisture stress at panicle initiation stage significantly reduced nutrient uptake, yield attributes and yield when compared to flowering stage but it recorded higher root traits.