With the objective of evaluating the effects of the gibberellic acid and thidiazuron on clusters characteristics of the grapevine Niagara Rosada, two trials were carried out. In the first trial, it was used gibberellic acid (AG3) 0, 15, 30, 45, 60, 75 and 90 mg.l-1, applied in the bloom and repeated 14 days later (E1E2) and in the other treatment, the same compound and doses applied only once, 14 days after the bloom (E2); in the second experiment, thidiazuron (TDZ) 0, 5, 10, 15, 20, 25 and 30 mg.l-1, applied four days before antesis and repeated six days after the bloom (E1E2); and in the other treatment, the same compound and doses applied only once six days after the bloom (E2). From the obtained results, it has been verified that the treatments with thidiazuron, increased the setting of the berries, resulting in the increment of the clusters mass and the significant thickening of rachis. The fruits treated with thidiazuron presented desuniform maturation, berries with reduced mass and size, compact clusters, with low commercial value. Increases in the number of berries with increments in the mass of the clusters, had been also observed with applications of gibberellic acid. For the variable mass of the clusters, the best results obtained from estimate of the regression equation have been verified with applications 54mg.L-1 gibberellic acid, with values of 198,8g.
grapevine; Vitis; growth regulator; gibberelin; cytokinin
