Different pruning and debudding in young walnut trees

In recent years, the cultivation of walnuts has been steadily increasing worldwide and it is recovering also in Italy. In a modern walnut orchard, the challenge is to combine early and high yields with good quality fruits. For this reason the tendency is towards higher planting densities and pruning patterns promoting early bearing. The aim of the work was to test different training techniques and evaluate the early ramification of the plants. The trial was carried out in a commercial orchard in Emilia Romagna region (central Italy). The four treatments compared were: a) farm management, which consists in topping the central axis of nursery trees 150 cm above the soil during the first year in the field and remove all the primary buds in the 30-40 cm below the cut but the two terminal ones; b) summer management, topping at 150 cm above the soil without debudding with summer pruning of lateral shoots; c) high topping management, topping at 200 cm above the soil without debudding with summer pruning of lateral shoots; d) no topping, debudding of the apical and lateral primary buds until 140 cm above the soil. Results show a different distribution and length of the shoots along the axis, in particular high topping and no topping resulted in the highest density of short shoots in the apical part of the axis. While farm and summer management had a more uniform distribution of the shoots that were more vigorous and so more suitable to form the future structure of the tree.