YIELD OF DRIP-IRRIGATED RICE (ORYZA SATIVA L.) RESPONSE TO WATER DEFICIENCY IN DIFFERENT GROWTH STAGES

. Rice drip irrigation cultivation is an efficient water-saving cultivation technique. However, it is a special water environment for rice, which makes rice vulnerable to water shortage during the whole growth period or at a certain stage. In this study, five water treatments were set up: drip irrigation regimes (DI), water deficient irrigation for 15 days at panicle differentiation stage (T1), booting stage (T2), flowering stage (T3) and grain filling stage (T4). Results indicated that the T1 treatment reduced the yield most, about 30.6% lower than that in DI treatment. T1 treatment significantly decreased the number of secondary branches and grains per panicle. The T2 and T3 treatment reduced the seed-setting rate of rice and led to yield reduction. The grain weight of grains on bottom secondary branches in T4 treatment was significantly decreased. Overall, In the drip irrigation management, further water shortage at different growth stages will lead to a reduction of yield. Therefore, in production practice, it is necessary to ensure adequate irrigation (soil water content kept 90% of the field water capacity at least) from the beginning of reproductive growth, especially in panicle differentiation stage. This provides a direction for breeding and water management under drip irrigation.