Investigation of oil and protein content and fatty acid composition of sunflower cultivars under different irrigation conditions

In order to study the effect of irrigation on fatty acid composition, oil and protein content of sunflower cultivars included Azargol, Allstar, Alison and Euroflor, an experiment was conducted at Experimental Field of the Agricultural Faculty of Bu-Ali Sina University in 2007. Treatments were arranged on split plot based on randomized complete block with three replications. The irrigation treatments were full irrigation, deficit irrigation by withholding irrigation at heading, flowering, seed filling, at heading and seed filling and at flowering and seed filling stages. The results indicated that the highest protein percent was obtained from deficit irrigation treatments at seed filling period (23.2%). The highest oil percent (40.9%) was obtained from full irrigation treatment same with deficit irrigation at heading stage (40.6%). The lowest protein (22.2%) and oil (38.5%) were obtained from full irrigation and water deficit at flowering and grain filling, respectively. The highest protein (23.8%) and oil (41.8%) were observed at Euroflor. The highest seed yield (4805 kg ha-1) was obtained from all cultivars at full irrigation and Euroflor at water deficit on seed filling stage. Full irrigation (1985.8 kg ha-1) and Euroflor cv. (1707.9 kg ha-1) have the highest oil yield. Deficit irrigation treatments at seed filling period have the highest oleic acid to linoleic acid ratio. Euroflor cv. had the highest oleic acid content (44.4%) and oleic to linoleic acid ratio (0.98) and had the lowest linoleic acid content (45.1%) and saturated fatty acids (10.5%). At all deficit irrigation at seed filling period produced the highest oil quality. The highest seed protein and oil percent and oil yield and quality belonged to Euroflor.