OLIVE FRUIT SET IN CENTRAL ITALY IN RESPONSE TO DIFFERENT PRUNING SYSTEMS

Pruning is advised in northern Mediterranean climates between the end of winter and flowering to reduce the risks of winter damage. The objective of the present experimental work was to investigate the influence of extending the pruning time on fruit set and production of three Italian cultivars (‘Raggia’, ‘Maurino’ and ‘Leccino’) in Marche region (central Italy). Pruning was performed on 5-year-old olives in April (after bud break) and June (after full bloom). Three pruning treatments were applied: minimal pruning, heavy pruning and no pruning. Results showed that the absence of pruning, minimal pruning in April and pruning in June (after full bloom) did not reduce the fruit set, while heavy pruning in April (after bud break) strongly reduced fruit set and caused strong vegetative growth (water sprouts emission). Moreover, April heavy pruning strongly reduced fruit production per tree, while no differences were recorded for minimal pruning in April and pruning in June. Furthermore, fruit set return in 2010 on 2-year-old fruiting branches was affected by pruning intensity and time, while no differences were found among treatments for the fruit set on 1-year-old fruiting shoots. This study suggests that olive pruning in central Italy can be performed also after full bloom to increase the fruit set, control the vegetative growth of the canopy and exploit the whole plant pollination potential.