In the northwestern of São Paulo State, 'Niagara Rosada' grapes are harvest off-season in traditional vine-growing areas, between June and November. However, because of soil and climate conditions, clusters and berries are small, what is unfavorable for trading. In this context, a trial was carried out in a vineyard located in Junqueirópolis-SP, Alta Nova Paulista region, with the objective of studying the effects of plant regulators on cluster and berry characteristics of 'Niagara Rosada' grapes. For treatments, it was used thidiazuron at 5 or 10 mg.L-1 and gibberellic acid at 35 mg.L-1, associated or not. It was realized 1, 2 or 3 weekly applications, beginning 14 days after full bloom, by dipping cluster in solution contained in a recipient. The following variables were evaluated: weight, length and width of clusters and berries; weight of rachis; number of berries; number of seeds; total soluble solids content; total titrable acidity, pH and TSS/TTA ratio of juice. Between the different treatments tested, 2 applications of thidiazuron at 5mg.L-1, was the most promissory for commercial use, leading to increase cluster weight in 33,7%, and berry weight in 22,4%; without changing total soluble solids content, total titrable acidity, pH and TSS/TTA ratio of juice. Plant regulators applications also improved rachis weight and berry width.
Vitis labrusca; vine; fruits; gibberellic acid; thidiazuron
