Influence of Irrigation Regimes on Quality Attributes of Olive Oils from Two Varieties Growing in Lebanon

An increasing interest on supplemental irrigation is observed in modern olive orchards because of its effect in increasing yield. In this study, the effect of three irrigation regimes (0, 60 and 100% ETC) on quality and chemical composition of olive oil is assessed in Baladi and Edlbi varieties planted in Lebanon. Significant differences (p<0.05) between varieties were observed for the majority of studied traits. Meanwhile, the response to irrigation regimes was strongly different between varieties. In Baladi variety, irrigation regimes resulted in increasing fresh fruit weight together with slight effects on oil yield, quality and composition. Only oleacein content showed significant decrease with irrigation (50.35 mg/kg for 0% ETC, 28.25 for 60% and 34.60 for 100%). On the contrary, in Edlbi variety, irrigation resulted in a strong decrease of total phenols (509.91 mg GAE/kg for 0% ETC, 385.87 for 60% and 365.74 for 100%) and chlorophylls (20.83 mg/kg for 0% ETC, 14.54 for 60% and 14.81 for 100%). Curiously, 60% ETC showed high content of the majority of individual phenols, including higher than 0% ETC.