Response of safflower Seed quality characteristics to different soil fertility systems and irrigation disruption

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 (I1), irrigation disruption at vegetative growth stage (I2), and irrigation disruption at reproductive growth stage (I3). 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) (T1), and (Urea + Humix + Biosoulphour) (T2). Results showed that the highest and lowest seed yield was obtained from the I1 and I2 irrigation regimes, respectively. Whereas T2 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 I3B and I1O treatment, respectively. I1B and I3C 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 I2 and I3 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.