Effect of Irrigation Regimes on Oil Content and Composition of Safflower (Carthamus tinctorius L.) Cultivars

Safflower oil contains a large amount of unsaturated fatty acids, however, the composition of the oil may be affected by drought stress. This experiment determined the effect of three irrigation regimes (60, 75 and 90% soil moisture depletions of available water) on oil composition of safflower cultivars (Kuseh, PI and IL111). Amounts of oil and oil composition of the seeds were determined by gas chromatography (GC). The oil contents of IL111, PI and Kuseh cultivars were 30.73, 27.63 and 25.25%, respectively. The oil contents, palmitic, stearic, oleic and linoleic acid contents were reduced by about 13, 63, 60, 14 and 10% by drought, respectively. The stearic acid contents of PI, IL111 and Kuseh were reduced by 72, 61 and 37% and palmitic acid contents of the same cultivars were reduced by drought by 65, 53 and 51%, respectively. Whereas, the linoleic acid contents of Kuseh, PI and IL111 were reduced by only 10, 8 and 5% and oleic acid contents of the same cultivars were reduced by only 14, 13 and 14% under the drought stress, respectively. The results showed that although drought stress reduced the amount of oil and oil composition of safflower cultivars, the decrease was due to a dramatic reduction in saturated fatty acids contents. Thus, proper irrigation regimes may enhance safflower oil quality.