Two trials were carried out in vineyards located in Jundiaí-SP, with the objective of studying the effects of growth regulators applications on 'Niagara Rosada' grapes. In the first trial, it was used thidiazuron (TDZ) at 5 or 10mg.L-1, and/or gibbellic acid at 100mg.L-1. In the second experiment, the following doses of thidiazuron were used: 0; 2.5, 5.0, 7.5, 10.0, 12.5 and 15.0mg.L-1. The growth regulators were applied by dipping the cluster 14 days after full blooming. It was evaluated weight, length and width of clusters and berries; rachis weight; number of berries; number of seeds; total soluble solutes content and total titratable acidity of juice. In the first experiment, the highest weight, length and width of berries were verified to the treatments with thidiazuron associated to gibberellic acid. Treatments with only gibberellic acid was not effective in increasing berry size and reduced number of berries per cluster. In the second trial, thidiazuron applications increased linearly weight of rachis and cluster; and weight, length and width of berries. There weren't significant differences for total soluble solutes content, total titratable acidity, number of seeds and cluster width.
Vitis labrusca; growth regulator; fruits; gibberellin, cytokinin
