International Research Journal of Applied and Basic Sciences. Vol., 3 (5), 968-976, 2012 Available online at http:// www. irjabs.com ISSN 2251-838X ©2012 Response of safflower Seed quality characteristics to different soil fertility systems and irrigation disruption Omid Mohsennia 1 , Jalal Jalilian 2* 1-MSc. Student of Department of Agronomy and Plant Breeding, Faculty of Agriculture, Urmia University, Iran 2- Assistant Professor, Department of Agronomy and Plant Breeding, Faculty of Agriculture, Urmia University, Iran. *Corresponding Author Email: j.jalilian@urmia.ac.ir Abstract To study the quality of safflower seed in response to plant nutrition under water deficit stress condition, an experiment was carried out at the Research Farm of Faculty Agriculture of Urmia University, Urmia-Iran, during 2010. The experimental design was split-plot, laid out in Randomized Complete Block with three replicates. The main plots were well-irrigation (I 1 ), irrigation disruption at vegetative growth stage (I 2 ), and irrigation disruption at reproductive growth stage (I 3 ). The subplot included seven levels of soil fertilization: Control (C), Urea (U), Humix as organic fertilizer (O), Biofertilizers (Nitroxin (N), Biosoulphour (B)), integrated fertilize treatments: (Urea + Humix + Nitroxin) (T 1 ), and (Urea + Humix + Biosoulphour) (T 2 ). Results showed that the highest and lowest seed yield was obtained from the I 1 and I 2 irrigation regimes, respectively. Whereas T 2 and control fertilization treatments produced the maximum and minimum seed yield, respectively. Oil and protein percentages were significantly influenced by the "irrigation regimes × fertilization" interaction. So, the highest (28.41 %) and lowest (21.01 %) protein percent was obtained from the I 3 B and I 1 O treatment, respectively. I 1 B and I 3 C fertilization treatments had the highest (26.92 %) and the lowest (20.68 %) oil percentage. The highest (75.20 %) linoleic and oleic acid (13.95 %) were obtained in plants under well irrigation regimes. But the lowest of them were observed in plants under I 2 and I 3 irrigation regimes treatments, respectively. The existence of a water deficit strikingly decreased the oil percentage, oleic acid and linoleic acid concentrations of the seeds. However, it increased the protein percentage, palmitic acid, and stearic acid in safflower seeds. Keywords: Biofertilizer, Fatty acid, Oil, Organic fertilizer, Protein. Introduction In recent years, there has been an increasing demand for agricultural products with specific qualities (jalilian et al., 2012). The demand for vegetable oils for food purposes has entailed a considerable expansion of oilseed crops all over the world (Corleto et al., 1997). Vegetable oil is one of the fundamental components in foods and has important functions regarding human health and its nutritional physiology (Necdet camas et al., 2007). Particularly, consumers have demanded healthier oils, naturally low in saturated fat such as olive, safflower, canola and sunflower oils. The quality of oils is associated with their fatty acids (FA) composition, particularly with respect to the percentages of oleic (omega-9), linoleic (omega-6) and linolenic (omega-3) acids (jalilian et al., 2012). Safflower oil contains the saturated fatty acids palmitic (C16:0) and stearic (C18:0) and the unsaturated fatty acids oleic (C18:1), linoleic (C18:2) and linolenic (C18:3) (Camas and Esendal, 2006). Oleic acid has desirable frying characteristics of stability and a bland flavor (Yeilaghi et al., 2012), while linoleic acid reduces the cholesterol level in the blood (Wilson et al., 2006). Standard safflower oil contains about 6–8% palmitic acid, 2–3% stearic acid, 16–20% oleic acid, and 71–75% linoleic acid (Velasco and Fernandez-Martinez, 2001). Consumption of oils with a high