Irrigation regime affects yield and oil quality of olive trees.

The field trial was carried out in 97, 98 and 99 in a drip irrigated olive orchard planted in 1992 at the C.N.R. Irrigation Institute experimental station (14o43' E 41o06' N; 250 m above sea level). The training system adopted was the monocone and trees were spaced 6 m between the rows and 3 m on the row. Five table and double attitude cultivars ( Ascolana Tenera Nocellara del Belice , Maiatica , Itrana and Kalamata ) were tested under four water regimes: a rainfed control and three treatments that received a water depth equivalent to 33, 66 and 100% of estimated crop evapotranspiration, respectively. The positive response of the cultivars under study to irrigation in terms of yield and oil and fruit quality is discussed. The positive yield response to irrigation was attributed both to increased mean fruit weight and number of fruit per plant. The oil fatty acid composition was not affected by irrigation regime, while the polyphenol content decreased when irrigation level increased.