Growth Performance and Radiation Use Efficiency of Transplanted Rice under Varied Plant Densities and Nitrogen Levels

A field experiment was conducted at Agricultural Research Institute, Rajendranagar, Hyderabad during the Kharif season of 2012 with four nitrogen levels (120 kg ha-1, 180 kg ha-1, 240 kg ha-1 and 300 kg ha-1) as factor one and three plant densities - farmers practice – zigzag planting (28 hills m-2), 15×15 cm (44.44 hills m-2), 25×25 cm (16 hills m-2) as factor two in randomized block design with factorial concept replicated thrice. Increased number of tillers m-2, leaf area index (LAI), intercepted radiation and radiation use efficiency (RUE) was noticed with increased plant density from 16 to 44.44 hills m-2. Application of 300 kg N ha-1 showed more number of tillers m-2, LAI, intercepted radiation and RUE and was onpar with 180 kg N ha-1. A highly significant linear relationship observed between cumulative intercepted photosynthetically active radiation (PAR) and biomass production. So plant density of 44.44 hills m-2 and application of 180 kg N ha-1 could be considered as optimum for improved growth and radiation use efficiency of transplanted rice in South Telangana Region of Telangana State