RESPONSE OF TWO SORGHUM CULTIVARS (Sorghum bicolor (L.) Moench) TO WATER STRESS UNDER FIELD CONDITION 1-EFFECTS ON GRAIN YIELD, YIELD COMPONENTS, CONSUMPTIVE USE AND WATER USE EFFICIENCY

Abstract

To study the effect of deficit irrigaton water on grain yield, consumptive use and water use efficiency of two sorghum cultivars (Sorghum bicolor (L.) Moench), a field experiment was conducted at the College of Agriculture, Abu Graib, (latitude 32.2 N, longitude 44.2 E and altitude 34.1m) during the fall seasons of 2004 and 2005.The experiment was arranged in a split-plot design with four replications. Control treatment (S1 a depletion of 50% of available water] and three other treatments S2,S3,S4 which represented 75%, 50% and 25% of the water amount of the control respectively. All these treatments were assigned in the main plots whereas cultivars (Inqath and Kaffir-2) were assigned in the sup-plots. The results showed that Irrigation treatment (75% watering amount of the control) could saved on average 1576.35 m3 amount of water/ha in both seasons without any significant reduction in grain yield compared with that of the control treatment which gave the highest grain yield (10.91, 9.78) ton/ha in the first and the second season respectively. However watering with 50% and 25% amount of water of the control treatment caused a reduction in grain yield reached on average 32% and 54% respectively compared with that of the control treatment. 75% and 50% watering treatment gave the best water use efficiency (1.75, 1.85) and (1.68, 1.70) kg/m3 in the first and the second season respectively compared with the control treatment which gave (1.63, 1.38) kg/m3 at the two seasons respectively .Significant difference between cultivars were reveald" Inqath"gave the best grain yield 8.64 and 8.28 ton/ha, in the first and second season respectively compared with Kafir-2 cultivar. Also the same cultivar gave the best water use efficiency for grain yield (1.9 and 1.79) kg.m-3 in the first and second seasons respectively. Maximum water consumptive use was reached for control treatment of ''Inqath "(729) mm. and Kafir-2( 688.5) mm/season.