Ben-Gal, A., Institute of Soil, Water and Environmental Sciences, Gilat Research Center, Agricultural Research Organization, Mobile Post Negev 2, 85280, Israel
Dag, A., Institute of Plant Sciences, Gilat Research Center, Agricultural Research Organization, Mobile Post Negev 2, 85280, Israel
Basheer, L., Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, P.O. Box 12, Rehovot, 76100, Israel
Yermiyahu, U., Institute of Soil, Water and Environmental Sciences, Gilat Research Center, Agricultural Research Organization, Mobile Post Negev 2, 85280, Israel
Zipori, I., Institute of Plant Sciences, Gilat Research Center, Agricultural Research Organization, Mobile Post Negev 2, 85280, Israel
Kerem, Z., Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, P.O. Box 12, Rehovot, 76100, Israel

Five rates of water application were applied in a 4 year study on olive (Olea europaea) varieties 'Barnea' and 'Souri'. Increased irrigation lead to increased tree-scale oil yields, lower polyphenol content, and, frequently, higher oil acidity. These effects were predominant in "off" years. The fatty acid profile was influenced primarily by bearing level and variety and secondarily by irrigation rate. The saturated to unsaturated fatty acid ratio was higher in "off" than in "on" years, and the monounsaturated fatty acid to polyunsaturated fatty acid ratio was higher in "on" years as a result of the fact that oleic and stearic acids were higher in "on" years, while palmitic, palmitoleic, and linoleic acids were greater in "off" years. Squalene was higher in 'Souri' than in 'Barnea' oils, was not affected by bearing cycle, and was consistently lower in oil from trees receiving the lowest irrigation level. © 2011 American Chemical Society.