Effects of different pruning intensity applications on plant shape and yield quality of 'SRA 63' Clementine

Pruning of Clementine requires a lot of time: more than 50 days of work per hectare in the traditional forms of orchard management. Because of the high cost and the lack of specialised workers, we observe a general tendency to delay the frequency of pruning in the citrus orchards. On the other hand regular pruning is of fundamental importance to have good fruit quality, to maintain health status of the orchard, and to store their regular productivity. In order to optimise the Clementine pruning technique, reduce the time of execution and maintain a good level of yield of better quality a field experiment was designed. In 1996 a commercial orchard of 'SRA 63' Clementine located in Southern East Sardinia was selected for the experiment. Plants were grafted on 'Troyer' Citrange, twenty-year-old, spaced 7x5 m, shaped to globe, over 4 m in height, and showed an excessive number of main branches (about 7-8 per tree) with a dense canopy. The entire orchard was preliminarily submitted to a gradual shape pruning during the first four years. In 2000 two main plots of 72 plants each were designed: A) pruning every year; and B) pruning every two years. The orchard was observed for a further period of four years for the following characters: trunk section area; canopy size, working time for pruning; pruned wood weight; fruit yield; fruit size. In both pruning applications (A and B) the canopy was more open and green than in the past, with a improvement of the plant heath status, a reduction of the number of treatments, water for irrigation and fertilizers, less working time for harvest, and with a significant better fruit size and increase of the production value.