Effect of Leaf-to-Fruit Ratio and Girdling on Gas Exchanges, Fruit Growth and Carbohydrate Contents at Different Stages of Fruit Development of Olea europaea L. 'Picholine'

The effects of different source-sink ratios on fruit quality were studied for the table olive cultivar 'Picholine'. This cultivar represents 15% of the production of table olives in Tunisia. Fruit size is an important quality parameter for table olives as small fruits have lower economical value. Three tertiary branches/tree were selected on 27-years-old olive trees (10 trees in total) at the start of the growing season 2009. After fruit set in early May four fruit-to-leaf ratios were imposed on 1-year-old wood (no fruits, 1: 1, 1: 2, 1: 3) of each branch. Apexes of all shoots were removed in order to reduce the vegetative sinks. In mid-July five trees were randomly selected and all branches were girdled. The absence of fruits or girdling decreased leaf net photosynthetic rate (A(n)) and increased leaf carbohydrate contents. Girdling stimulated fruit growth, while the effect of leaf-to-fruit ratio was less pronounced.