Oil Content and Composition of Sesame (Sesamum indicum L.) Genotypes as Affected by Irrigation Regimes

The fatty acid composition of sesame seed oil determines its commercial value, and drought stress and genotype may affect both the quality and quantity of oil that is extractable by sesame seed processors. Therefore, this experiment was conducted in a field located in Isfahan, Iran, to determine the effect of three irrigation regimes [55 % (I ₁, as control), 75 % (I ₂) and 85 % (I ₃) of depletion of soil available water] on the oil content and composition of ten sesame genotypes (Isfahan4, Shahreza, Borazjan, Ahvaz, Kal, Shiraz, Markazi, Ardestan, Ultan and Isfahan1). Seed oil content and palmitic, linoleic, linolenic, stearic and oleic acid contents were determined during 2010–2012. Shahreza under I ₁, Shahreza and Ardestan under I ₂ and Isfanahan4 under I ₃ irrigation regimes produced the highest oil content, while Kal under I ₁ and I ₂ and Isfahan4 under I ₃ irrigation regimes produced the highest oil yield. Ultan had the lowest palmitic acid content under all three irrigation regimes, while Isfahan4 had the highest reduction in palmitic acid content under I ₂ and I ₃. Borazjan produced the lowest stearic and highest linoleic acid contents under the I ₁, I ₂ and I ₃ irrigation regimes. Kal, Kal and Ardestan, and Ardestan and Isfahan1 produced the highest oleic acid under I ₁, I ₂ and I ₃, respectively. Shahreza under I ₁ and I ₂ and Isfahan4 under I ₃ had the highest linolenic acid content. The results showed that the sesame oil content and composition were genotype-drought level specific, and based on oil yield production and percent reduction in saturated and increase in unsaturated fatty acid contents, Isfahan4 was the most drought-tolerant genotype.