PEACH AND NECTARINE TRAINING SYSTEMS IN HIGH-DENSITY PLANTING: NEW TRENDS IN ITALY

The last few decades have seen far-reaching changes in Italy's fruit-growing industry, including substantial developments in training systems and planting density. Innovations began on apple and pear with the modification of the traditional palmette to early and free palmettes and the use of dwarfing rootstocks. The success of these changes caused them to be applied to commercial orchards, including peach and nectarine plantations. In these species, new training systems and pruning techniques were introduced that, by complementing the trees' growth habit and physiological requirements, resulted in earlier fruiting and more efficient management operations, such as pruning, thinning and harvesting, and reduced production costs. Of all the training systems proposed for high-density planting only a few have proved to be suitable; the most frequently adopted are those characterized by high radiant energy interception and constant yields of high-quality fruits. Of signal importance in the development of these training systems for use in high-density peach and nectarine orchards is the regulation of apical dominance and control, by choice of rootstocks and the application of summer pruning over the training period, to enable balanced canopy growth. The characteristics of training systems, pruning techniques and high-density planting are reported and discussed in light of recent insights into the biological and physiological principles controlling the vegetative and fruit growth habits of the trees.