Effects of water-saving irrigations on different rice cultivars (Oryza sativa L.) in field conditions

A more efficient water use system is needed for agriculture. This is more evidence for rice production with a higher water use for economical production. A large cultivar×water regime interaction exists for grain yield in rice. Therefore, information is required to adopt new rice cultivars with high yield potential under water-saving conditions. The objectives of this study were to analyze the straw yield, grain yield, yield components, water use and water productivity (WP) of five rice cultivars (Anbarboo-22, Ghasroddashti, Cross-Domsiah, Hasani, and Rahmat-Abadi) under water-saving irrigation regimes (intermittent flood irrigation with 1-and 2-day intervals after disappearance of standing water, I-1-D, and I-2-D, respectively) compared with continuous flood irrigation (CFI) to adopt the elite cultivars for these conditions. In general, Anbarboo-22 cultivar totally failed in field trial due to susceptibility to disease in 2005 and 2006. Among the other cultivars, Cross-Domsiah showed the highest grain yield, harvest index, number of panicles per hill and the lowest unfilled grain percentage in two years field experiments. Furthermore, its grain yield was the highest at water-saving irrigation regimes in comparison with the other cultivars, therefore, Cross-Domsiah is the elite cultivar in water-saving irrigation conditions especially with 1-day irrigation interval, however, Ghasroddashti cultivar is recommended in next order for I-1-D treatment. Based on the selected drought indices, Cross-Domsiah was the most drought tolerant cultivar and Ghasroddashti was in the second order. Furthermore, it is concluded that unfilled grain percentage and harvest index are found to be the most suitable traits for selection of rice cultivars with high yield potential.