This study aimed to evaluate the interference that the location of the leaf removed by defolation in grapevine has on fruits quality and yield. Such experiment was performed using Niagara Branca and Concord, both Vitis labrusca, and Cabernet Sauvignon e Merlot, both Vitis vinifera, trained in a unilateral cordon system during the 2006/2007 harvesting. The experiment was disposed in a randomized block design, with four replications and four plants per plot. The following treatments were tested: T1 (no defoliation), T2 (removal of leaves located in the opposite side of the grapes), T3 (removal of leaves located under the grapes) and T4 (removal of leaves located under and in the opposite side of the grapes). The Vitis labrusca received an additional treatment (T5) consisting of leaves removed above the grapes. These treatments were applied during the change of berries color for Concord, Cabernet Sauvignon and Merlot grapes and in the beginning of berries softening for Niagara Branca grape. After the harvesting, the grapevine production, cluster weight, total soluble solids, total titratable acidity and pH were evaluated. It was observed that the defoliation until the grapes height did not influence the quantity and quality of grapes. However, when the defoliation was carried out above the clusters, there was a delay in the maturation of american grapes. This condition shows that is not necessary a selective desfolation until the clusters height on grapevines, when it is realized during the initial fruit ripening phase.
green pruning; Vitis sp.; maturation; plant physiology