Response of different rice cultivars (Oryza sativa L.) to water-saving irrigation in greenhouse conditions

Due to increasing water and growing demand for food 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 of six rice cultivars (Anbarboo-22, Ghasroddashti, Cross-Domsiah, Hasani, Rahmat-Abadi, and Doroodzan) under water-saving irrigation regimes (intermittent flood irrigation with 1-and 2-day intervals, I-1-D, and I-2-D, respectively) compared with continuous flood irrigation (CFI) to adopt the elite cultivars of semi-arid area for water-saving conditions. Results indicated that under water-saving irrigation regimes (I-1-D), Doroodzan, Anbarboo-22, and Cross-Domsiah cultivars produced higher grain yields and are elite cultivars, however, under I-2-D irrigation regime only Anbarboo-22 cultivar was an elite cultivar. Based on the harvest index criterion, Doroodzan and Anbarboo-22 cultivars are the elite cultivars under water-saving irrigation regimes. The grain yield of the cultivars was mostly controlled by 1000-grain weight and the order of the other yield components were number of grains per panicle > number of panicles per unit area > unfilled grain percentages. Under CFI, Doroodzan cultivar resulted in highest water productivity (WP) as 0.52 kg m^-3 and Cross-Domsiah and Anbarboo-22 cultivars with WP of 0.40 and 0.31 kg m^-3 were in second and third place, respectively. Furthermore, based on the drought tolerance indices, it is concluded that Doroodzan at first place and Anbarboo-22 and Cross-Domsiah cultivars at second place may be considered as drought tolerant cultivars that can be used in further field study with water-saving irrigation regimes i.e., intermittent irrigation with 1-and 2-day intervals in Fars province.