Effect of Rooting Pattern on Rice Productivity under Different Water Regimes

Three rice varieties, viz. ADT 31 (drought tolerant) CO 41 (upland) and IR 50 (drought susceptible), were employed to study their rooting patterns under different water regimes. ADT 31 had better root penetration and distribution under water stress situation compared to others. The values on root weight also established a similar trend. Isotopic studies with ³²P also provided evidence in this regard wherein the variety ADT 31 showed its adaptiveness to drought. Marginal reduction in plant height, less tiller production and leaf area reductions were noted in ADT 31 and CO 41 under decreasing soil moisture which showed its ability to cope with the water stress situation. Though IR 50 recorded higher grain yield at normal irrigation, a drastic reduction was noted under extreme water deficit. But ADT 31 recorded consistent values in all situations with slight marginal reduction which evidently proved the interdependent nature of rooting pattern and its influence on productivity.