Effect of iron application methods on grain yield, yield components, oil content and fatty acids profile of spring safflower cv. Goldasht under deficit irrigation conditions

To study the effect of iron application methods on the yield, yield components, oil seed and fatty acids profile of a spring safflower cultivar Goldasht (IL-111) under deficit irrigation conditions, a field experiment was conducted in 2011 and 2012 in research field of the Faculty of Agriculture of Shahed University, Tehran, Iran. The experiment was set up as split-plot arrangement in randomized complete block design with four replications. The main plots consisted of two levels of irrigation treatments: 1: full irrigation (I1: irrigation at 50% soil moisture depletion relative to field capacity) and 2: deficit irrigation at the flowering stage (I2: irrigation at75% soil moisture depletion relative to field capacity). The subplots consisted of eight levels of Fe- EDDHA, half of which were soil applications (S1:0, S2:50, S3: 100 and S4:150 kg.ha-1) and the remaining half were foliar applications (F1:0, F2:1, F3:2 and F4:3 g.l-1). In general, grain yield and the oil content were affected by the interaction of irrigation ×Fe. Results showed that with full irrigation and an increase in application of Fe, the grain yield and grain oil content increased significantly. With a decrease in soil moisture to 75% of the field capacity, the highest grain yield and grain oil content were obtained with the F2 treatment, i.e., 1 g.l-1. Grain yield and oil content were 2535and 1042 kg.ha-1, respectively, in 2011 and 3176 and 1440 kg.ha-1, respectively, in 2012. Mean comparisons indicated that, in years, total biomass, harvest index and oil content were significantly affected by the application of Fe to the soil under water stressed conditions. The foliar application of Fe resulted in a significant increase in the amount of linoleic acid and decreased palmitic acid under a water deficit, while the soil application of Fe had the greatest effect on oleic and stearic acids. Grain yield and oil content in Fe at 1 g.l-1 treatment increased by 53.7% and 162.2%, in 2011 and 29.2% and 73.5%, in 2012, respectively, in comparison with treatment S4 (150 kg.ha-1). It can be concluded that the foliar application method under deficit irrigation condition can increase grain yield and improve the oil quality of safflower cv. Goldasht.