EFFECT OF ROOTING PATTERN ON RICE PRODUCTIVITY UNDER DIFFERENT WATER REGIMES

Three rice varieties, viz. ADT 31 (drought tolerant) CO 41 (upland) an d IR 50 (drought susceptible), were employed to study their rooting pa tterns under different water regimes. ADT 31 had better root penetrati on and distribution under water stress situation compared to others. T he values on root weight also established a similar trend. Isotopic st udies with P-32 also provided evidence in this regard wherein the vari ety ADT 31 showed its adaptiveness to drought. Marginal reduction in p lant height, less tiller production and leaf area reductions were note d 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 note d under extreme water deficit. But ADT 31 recorded consistent values i n all situations with slight marginal reduction which evidently proved the interdependent nature of rooting pattern and its influence on pro ductivity.