Effect of Deficit Irrigation on Agronomic Characteristics of New Sunflower Hybrids

To evaluate the effect of deficit irrigation on agronomic characteristics of new sunflower hybrids and to determine drought tolerant cultivars, an experiment was conducted based on a randomized complete block design (RCBD), with three replications during 2013–14 at the Agricultural Research Station of Islamabad-e-Gharb, Kermanshah, Iran. In this experiment, four new hybrids of sunflower (Farokh, Shams, Ghasem and Barzegar) were evaluated in three irrigation regimes (full irrigation, mild stress and severe stress by supplying 100, 75 and 50% of the crop water requirement). Results of combined analysis of variance showed that the effect of irrigation regime and genotype on all traits including days to flowering and physiological maturity, seed filling duration, head diameter, number of seeds per head, plant height, seed yield, biological yield and harvest index was significant (p≤0.01). The interaction of irrigation regime and genotype on all traits (except for the number of seeds per head) was significant. The results of the mean comparison showed that the seed yield of medium maturing hybrids (Shams and Barzegar) in all three irrigation regimes was higher than the early maturing hybrids (Farrokh and Ghasem). The highest seed yield (5007 kgha-1) was obtained in Barzegar hybrid with full irrigation, while Ghasem hybrid produced the lowest seed yield (1859 kgha-1) under severe stress conditions.