PJB-2008-22
WATER AND RADIATION USE EFFICIENCIES OF TRANSPLANTED RICE (ORYZA SATIVA L.) AT DIFFERENT PLANT DENSITIES AND IRRIGATION REGIMES UNDER SEMI-ARID ENVIRONMENT
S. AHMAD1*, M. ZIA-UL-HAQ2, H. ALI1, S.A. SHAD1, A. AHMAD3, M. MAQSOOD3, M.B. KHAN1, S. MEHMOOD1 AND A. HUSSAIN3
Abstract
Growth and yield of rice (Oryza sativa L.), in response to plant densities and irrigation (optimum to stress) were analyzed in terms of interception and utilization of photo- synthetically active radiation (PAR) and water use efficiency (WUE). The amount of PAR intercepted and cumulative evapotranspiration (ET) by each treatment was estimated from the measured leaf area index. The relationships between total dry matter, grain yield and accumulated intercepted PAR and cumulative ET were linear. Yield differences among the treatments were attributed to the amount of PAR intercepted and water transpired their efficiencies of utilization or both. The fraction of intercepted radiation and WUE was significantly affected by the plant densities and various irrigation regimes, while, radiation utilization efficiency (RUE) and water use efficiency (WUE) for TDM varied from 1.15 g MJ-1 to 1.36 g MJ-1 and 22.6 kg ha-1 mm-1 to 24.3 kg ha-1 mm-1 during both the seasons.
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