Phenological variations, yield differences and free proline accumulation in rice under alternate inundation and suspension of irrigation in Central Thailand

Abstract

Pot and field experiments were conducted to investigate the phenological and physiological adjustments, yield performance and water productivity of rice under variable periods of suspension of irrigation. Four different water management schedules [viz. conventional water management (CWM), 2-week inundation followed by 2-week suspension of irrigation (I2 S2), 1-week inundation followed by 3-week suspension of irrigation (I1 S3), and 1-week inundation followed by 4-week suspension of irrigation (I1 S4)] were evaluated in greenhouse pots with transplanted rice. Only CWM, I2 S2, and I1 S3 were tested under field conditions. In the greenhouse pot experiment, the commencement of flowering and physiological maturity of rice occurred in the shortest period with CWM, and delayed with increasing the period of suspension of irrigation during vegetative phase. Some of shoot and root growth parameters of rice had significant differences among different water management practices. Free proline accumulated in leaves was lowest in CWM, increased with increasing the period of suspension of irrigation. The I1 S3 water management reported highest water productivity. Field experiment conducted, confirmed the results observed in the greenhouse experiment showing similar pattern of shoot and root growth characteristics and free proline accumulation in rice plants. The water productivity and grain yield was significantly higher in I2 S2 over CWM and I1 S3. Overall results suggest that the 2-week inundation followed by 2-week suspension of irrigation water management is a better option for water saving with higher yield in transplanted rice for 120 days old Suphan Buri 1 hybrid in Central Thailand.