COMPARATIVE STUDY OF ALTERNATE WETTING AND DRYING IRRIGATION SYSTEMS FOR YIELD AND WATER PRODUCTIVITY OF BASMATI RICE CULTIVARS UNDER CLAY LOAMS OIL CONDITIONS

The present study was conducted to evaluate the performance of four commonly grown Basmati rice (Oryza sativa L.) cultivars (Punjab Basmati, Chenab Basmati, Kisan Basmati and Basmati 515) under four irrigation treatments ranging from continuous flooding (IRC) to alternate wetting drying (AWD) with irrigation thresholds of IR15, IR20 and IR25 in which plots of each AWD treatment were re-flood to a depth of about 5 cm when the water level was dropped to a certain level (15, 20, and 25 cm) below field surface. The results revealed that IRC attributed by the highest total water use (1207.7 mm) and the lowest water productivity (0.38 kg m-3) produced the second highest grain yield (4.62 t ha-1). Whereas, IR15 saved 3638% of the irrigation water and produced the highest grain yield (4.7 t ha-1) with the water productivity of 0.63-0.66 kg m-3. Raising rice under IR20 and IR25 had significant influence on water-savings but produced considerable lower grain yield (33% and 44%) than IRC. Significantly, higher numbers of productive tillers were recorded under IRC while highest numbers of sterile spikelets per panicle were recorded in IR25. Plant height and harvest index were found to be reduced with increased water stress. In conclusion, Basmati rice cultivars can also be grown under AWD irrigation systems but beyond the certain level (IR15), AWD might incur a huge yield penalty.