Trunk Constriction Effects on Vegetative Vigour and Yield Efficiency in Olive Tree ( Olea europaea L.)

Abstract

Tree vigour is one of the most important issues in super-high density olive orchards (~1,600 tree ha -1 ). Tree vigour could be limited by horticultural pr actices such as pruning and fertilization but such practices have a limited effect and increase growing costs. The aim of this work was to test a new technique based on the application of a constriction to the trunk in order to obstruct the flow of sap in x ylem and phloem. To this end, on 5 cultivars trained in a super-high density olive orc hard in Central Italy, constrictions were applied by a plastic strap in 2009 and 2010, and we re removed at the end of the following year. At the end of the experiment, constricted tre es had smaller vegetative growth than the control trees. During the first experiment (200 9), in the constriction year, yield efficiency was higher in constricted trees. In the second year, low vigour cultivars (‘Arbequina’, ‘Maurino’ and ‘Moraiolo’) had a consi stent reduction of yield, while vigorous cultivars (‘Leccino’ and ‘Frantoio’) had s imilar yield but a slightly increased yield efficiency. No effect was detected in fruit c haracteristics, but the oil phenol content was higher in the constricted trees. In the second year experiment (2010), similar results were obtained, but yield efficiency increase and ve getative growth reduction were lighter because the trees were one year older than those of 2009 experiment. Trunk constriction was a successful technique for reducing tree vigour and enhancing tree yield efficiency, especially in vigorous cultivars. Keywords : Arbequina, Hedgerow, Productivity, Wiring.