Summer pruning is a cultural practice used to manage vineyard canopies, which has the main objective to improve grape and wine quality. In this way, this experiment was carried out between the 1993/1994 and 1996/1997 vintages using different summer pruning modalities. It was performed in a Merlot vineyard trained in the pergola system. There were 12 treatments and three replicates, where the experimental design was in complete blocks. The treatments consisted of control and 11 different summer-pruning modalities, all related to sprouting, topping, and leaf removal, some of them performed in different periods of the grapevine-vegetative cycle. The principal component 1 of the principal component analysis (PCA) of each year shows that the treatment 10 (sprouting + topping + leaf removal performed in the beginning of the bloom time, taking off all leaves below clusters) was discriminated in all years and treatments 7 (leaf removal performed 21 days before harvest, taking off half of leaves below clusters) and 6 (leaf removal performed 21 days before harvest, taking off leaves below clusters) in three of them; the PCA of the average of four years also shows this discrimination among them. It is shown that treatment 10 had a more intense summer pruning, characterized by variables indicating grapevines with lower vigor and yield than the other treatments.
Vitis vinifera; grape; summer pruning; sprouting; topping; leaf removal
