Effect of Different levels of Phosphorus Fertilizer on oil yield and their derivatives of three varieties of Safflower (Carthamus tinctorius L.)


Due to the important of Safflower oil in edible, industrial and medicine, this study was carried out under the rain-fed conditions at Experimental Farm of the College of Agricultural Sciences, University of Sulaimani at Bakrajo, during the winter season of 2017-2018, to study the effect of three varieties, namely (Zaafarani, Aidn and Al-Shamia), phosphorus applications (0, 50, and 100 Kg ha-1), and their interactions on oil yield, fatty acid compositions and some phenolic acid contents. Using Randomized Complete Block Design (RCBD) with split plot arrangement, with three replications, the main plots were allocated for the varieties and conducted in Randomized Complete Block Design (RCBD) with three replications, while the phosphorus levels implemented in sub-plots. Comparisons between means were carried out by the least significant difference (L.S.D) at 0.05 and 0.01 levels of significance. The results of this investigation confirm that the oil yield of the varieties ranged between 490-540 Kg ha-1, variety Al-Shamia produced the highest oil yield, and exceeded by approximately 50 Kg ha-1when compared to the lowest oil yield gained by Aidn. Al-Shamia recorded the highest significant concentrations of stearic, linolenic, linoleic, and oleic acids, while regarding to the phenolic contents the caffeic, ellagic, and p-hydroxybenzoic acids detected in more concentrations in Zaafarani compared to other two varieties, among the phenolics only the gallic acid detected with higher concentration in Al-Shamia followed by Aidn variety. The application of higher level 100 Kg ha-1of P2O5 showed increasing in oil yield significantly compared to the lower levels 50, and 0 kgha-1 P2O5, moreover it exceeded significantly the stearic, linolenic, linoleic and oleic acids compositions, but the higher levels of P2O5 only increase the content of caffeic and gallic acids, while decreased the content of ellagic and p- hydroxybenzoic acid. The interactions response of the varieties to P2O5 applications was not significant for the most traits of the study except for stearic acid composition, and ellagic, gallic, and p-hydroxybenzoic acids content.