Características dos cachos e bagas de uvas ‘Centennial Seedless’ tratadas com thidiazuron e ácido giberélico Characteristics of clusters and berries of ‘Centennial Seedless’ table grapes treated with thidiazuron and giberellic acid

Com o objetivo de avaliar os efeitos das doses de acido giberelico (AG3) e do thidiazuron (TDZ) nas caracteristicas dos cachos e bagas da uva ‘Centennial Seedless’, um experimento foi realizado em um vinhedo comercial em Sao Miguel Arcanjo (SP). Os tratamentos consistiram de AG3 nas doses de 0 e 5 mg L-1 associados as doses de 0, 2, 4, 6, 8 e 10 mg L-1 de TDZ, sendo estes reguladores vegetais aplicados aos 15 dias apos o pleno florescimento, via pulverizacao direta nos cachos. Foram avaliadas as variaveis diâmetro do pedicelo, indice de esbagoamento, massa, comprimento e largura dos cachos, bagas e engacos; teores de solidos soluveis, pH, acidez titulavel e relacao SS/AT do mosto. A dose de 8 mg L-1 de TDZ associada a 5 mg L-1 de AG3, resultou em maiores medias de massa, comprimento e largura dos cachos, sendo que esta interacao nao alterou o pH, a relacao SS/AT e o indice de esbagoamento dos cachos. O TDZ promoveu aumentos lineares sobre a massa e largura das bagas e reduziu os teores de solidos soluveis, sendo que do ponto de vista agronomico a dose de 8 mg L-1, apresentou-se mais promissora para uso comercial. Abstract With the objective of evaluating the effects of gibberellic acid (GA3) and thidiazuron (TDZ) on the physicochemical characteristics of ‘Centennial Seedless’ table grapes a trial was carried out in a commercial vineyard located in Sao Miguel Arcanjo (SP), Brazil. The treatments consisted of GA3 on the doses at 0 and 5 mg L-1 associated to 0, 2, 4, 6, 8 and 10 mg L-1 of thidiazuron, applied 15 days after full bloom, sprayed directly to the clusters. The following variables were evaluated: pedicel diameter, drop index, weight, length and width of clusters, berries and rachis; soluble solutes content, pH, titratable acidity and ratio SS/TA of the juice. The dose at 8 mg L-1 of TDZ associated to 5 mg L-1 of AG3 resulted in the highest means of cluster weight, length and width, this interaction did not alter pH, ratio and drop index of bunches. TDZ increased linearly the mass and width of berries and reduced soluble solids content and, from the agronomic point of view the dose of 8 mg L-1 was the most promissory for commercial use.