The present study focused on the effect of two agronomic practices pruning and irrigation on water status of tree, fruit growth and olive oil quality. One level of pruning (50% of the canopy volume were removed) had been tested compared to non pruned trees and they were combined with two irrigation treatments: trees irrigated usually as irrigation treatment (I) and trees subjected to water stress during the summer period as deficit irrigation treatment (ST). Midday stem water potential (Ps), fruit growth, oil yield, quality characteristics and fatty acids composition which were studied in virgin olive oil samples extracted from each treatment. The results showed that with measuring (Ps), the pruned trees were more subjected to water stress than to the control ones in both water conditions. These trees recorded the higher negative value of stem water potential more than -4KPa reflecting that the leaves of trees tended to desiccate. The combination of the effect of pruning and irrigation together had a positive effect on the fruit growth, oil yield and quality characteristics. Pruning affected positively the nutritional value of olive oil especially by increasing the content of antioxidant compounds (total phenols) and level of monounsaturated fatty acids (MUFA), oleic acid (C18:1), linolenic acid (C18:3) and decreasing saturated fatty acids (SFA).

Keywords: Pruning trees, irrigation, olive trees, water stress, stem water potential, oil quality.