Desenvolvimento da videira Itáliaem clima tropical de altitude / Development of Itália grapevine in humid subtropical climate

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Itália grapevine (Vitis vinifera L.) is the most consumed grapevine for fresh market in Brazil, with the State of São Paulo as the major producer. As a result of climate diversity through different regions of this State, grapevine production cycle varies widely. Besides, pruning in different periods of the year in the same region may alter the cycle duration. The cluster quality is determinant for commercialization, with berry size being highly valued by consumers. An alternative to improve berry size is the use of growth regulators. Two experiments were performed. Firstly, Itália grapevine development in humid subtropical climate (Cwa) was evaluated after pruning in different seasons. Secondly, cluster quality was evaluated after application of the growth regulators GA3 and CPPU at increasing concentrations, isolated or in association. The first experiment comprised six production cycles (pruning-harvest) in two experimental areas (three cycles per area), respectively, winter, summer and spring prunings. Visual evaluations were weekly performed from pruning to harvest, computing production cycle duration and intervals pruning-budburst, budburst-flowering, flowering-veraison and veraison-harvest. Cordon growth, fruit quality and determinate the degree-days were also evaluated for all periods. Experimental design was completely randomized with 25 replicates and one plant as plot. In the second experiment, gibberellic acid (GA3) and forchlorfenuron (CPPU) were applied isolated or in association on Itália grapevine clusters in three production cycles 25 days after flowering. Experimental design was a completely randomized 4X4 factorial (0, 10, 20 and 30 mg.L-1 GA3 X 0, 5, 10 and 15 mg.L-1 CPPU) with eight replicates for the first cycle and 3X3 factorial (0, 20 and 30 mg.L-1 GA3 X 0, 10 and 20 mg.L-1 CPPU) with ten replicates for the others cycles. Itália grapevine production cycle varies depending on pruning moment. Spring pruning usually decreases cycle duration while summer pruning increases the cycle duration. Flowering- veraison interval corresponds to the longest period of the production cycle regardless of pruning moment. Considering inferior and superior base temperatures of 10 and 30°C, degree-days was adjusted for flowering-veraison interval. There was no interaction between growth regulators GA3 and CPPU in all production cycles evaluated. The application of GA3 at 20 mg.L-1 associated with CPPU at 10 mg.L-1 in the pea stage improves cluster quality.

ASSUNTO(S)

phenology reguladores de crescimento vegetal grapevine plant development fenologia clima poda uva. pruning. climate desenvolvimento vegetal plant growth regulators

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