The effect of irrigation regims on qualitative and quantitative properties of three varieties of spring safflowers.

For optimum water resources utilization especially in arid and semi-arid rejoins in which the surface irrigation is prevailed, the effect of water stress on plants yield and yield quality through increasing irrigation interval is required. Safflower is a salt and drought tolerance plant, which is planted in 2000 hectare in Esfahan Province. The effect of irrigation regimes on qualitative and quantitative seed yield of three safflower cultivars namely: Esfahan-14, Arak-2811 and I.L.-114 for irrigation interval of 10, 15, 20 and 25 days for three years were studied using a split plot design in four replicates. The Irrigation regimes were in the main plots and genotypes in the subplots. The duration of vegetative and productive growth stages and plant dry weight at full flowering stage, plant height, number of head per plant, weight of thousand seeds, plot yield and, percent seed oil content were measured for each plot. The results were analyzed and the means were compared using Duncan multiple range test (P0.05). The Bartlet test shows that the combined three years analysis is not possible. The applied irrigation water were 400 to 700 mm, seed yield were 2663 to 1254 kg/ha and water use efficiency (WUE) was 0.395 to 0.254 kg seeds/m3 applied water, for the three growing season. The data show that the seed yield decreases by increasing irrigation intervals and there is no significant difference between 10 and 15 days irrigation intervals. Increasing irrigation interval enhanced crop maturity. Among studied safflower genotype: Esfahan-14 and Arak-2811 and I.L.-114, produced the lowest (0.323) and highest (0.374) WUE, respectively, by yielding 1956 and 2136 kg seed/ha. Among studied genotype percent seed oil content of Esfahan-14 (0.28) were lower than Arak-2811 (29.2) and higher than I.L.111 (24.3). Esfahan-14 had the tallest main stem and I.L.-114 the highest seed weight. Key words: Safflower, Irrigation Interval, Genotype, yield, yield components