EFFECT OF BUNCH THINNING IN THE EVOLUTION OF THE QUALITATIVE PARAMETERS OF THE GRAPE CV. CABERNET SAUVIGNON PRODUCED IN THE MOUNTAIN REGION OF SANTA CATARINA

The grape cv. Cabervet Sauvignon is economically very important, with currently 150 ha and continuously expanding vineyards in the mountain region of Santa Catarina (Brazil). Little information is available referring to maturation and the characterization of the grape. In 2005, a study was conducted at Francioni Vinícola with 800 ‘Cabernet Sauvignon’ plants in a vineyard planted in 2001 and grafted on Pausen 1103. A Y type trellis was established at 1.5 m between plants and 3.0 m between lines. Maturation was monitored at 28/02/05, 07/03/05, 14/03/05, 21/03/05 and 28/03/05. Five thinning treatments were established when the grapes were changing colour, 6, 9, 12 and 15 grape bunches per plant and the control with 18 bunches with a projected production of 1960, 2970, 3960, 4950, and 6940 kg ha^-1 respectively. Total soluble solids (TSS) were higher in the thinned treatments than in the untreated control, but there were no differences for phenols and acidity. The pH was too high in all treatments, suggesting that harvesting should be anticipated by one week. Berry growth was linear in the plots with 15 bunches/plant while in the other treatments, berry weight decreased after the 4^th measuring date following a polynomial correlation of the 2^nd degree. A similar behavior was observed for the anthocyanin content, with the exception of the treatment with 9 grapes/plant. It was concluded that thinning affects the anthocyanin accumulation, total soluble solids (TSS) and berries weight, but not in the accumulation of phenolic compounds.