The production of grapevines in regions of high altitude of Santa Catarina state is recent and there are few data on the behavior of different cultivars. The objective of this work was to verify the effect of different levels of shoot topping and evaluate the influence of two rootstocks on the characteristics of the fruit produced. The experiment was conducted in the city of São Joaquim, Santa Catarina state (28º17'38" S and 49º55'54" W), in an altitude of 1.250m, at Villa Francioni Vineyards, with Merlot grapevine grafted on Paulsen 1103 and Couderc 3309. The treatments consisted in different levels of shoot topping, keeping the leaf area of 4.5; 2.5; 2.0 and 1.5 m² kg-1 of grapes in two rootstocks. The variables evaluated were: number of berries per bunch, berry diameter, pH, total soluble solids, anthocyanins, total polyphenols index, length and weight of the bunch. Plants grafted on Paulsen 1103 showed the maximum efficiency maintaining a leaf area of 3.4 m².kg-1 of grapes, while plants grafted on Couderc 3309 showed the maximum efficiency maintaining a leaf area of 3.0 m².kg-1 of grapes. The rootstocks did not present difference for the phenolic compounds. In the 2005/06 cycle, plants grafted on Paulsen 1103 produced the largest berries, but with lower content of total soluble solids. In the 2006/07 cycle, plants grafted on Couderc 3309 produced heavier bunches.
Vitis vinifera L.; summer pruning; canopy management
