Oil content and fruit quality of nine olive (Olea europaea L.) varieties affected by irrigation and harvest times

Abstract

A field experiment was conducted on nine olive varieties with the objective of determining the effect of regulated deficit irrigation on olive oil content and physical quality parameters of fruits. Three irrigation levels were applied as a percentage of crop evapotranspiration (ETc) during the pit-hardening period: rainfed, R (0% ETc); deficit, D (50% ETc); and irrigated, I (100% ETc). Rainfall and ETc during the pit-hardening period were 78 mm and 164 mm, respectively. Olives were sampled four times during the normal crop harvest period. Withholding irrigation during the pit-hardening period (R treatment) reduced the fruit size of three of the varieties, but had no effect on oil contents, while saving 35% irrigation water compared with the I treatment. The D treatment resulted in 17.5% water saving with minor effects on fruit size, timing of maturity and oil content. The olive cultivars responded differently to irrigation treatments in terms of most of the parameters considered. This necessitates cultivar-specific irrigation management.