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 watersaving 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 watersaving 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.