Growing degree-days for the ‘Niagara Rosada’ grapevine pruned in different seasons

Abstract

Plant growth and development are proportional to biological time, or the thermal time of the species, which can be defined as the integral of the temperature over time between the lower and upper temperature developmental thresholds. The objective of this study was to investigate the efficiency of the growing degree-day (GDD) approach for vines of the 'Niagara Rosada' cultivar pruned in winter and summer seasons, and physiological phases (mobilisation and reserve accumulation) in a humid subtropical region. The experiment was carried out on 13-year-old plants in Piracicaba, São Paulo State-Brazil, evaluating 24 production cycles, 12 from the winter pruning, and 12 from the summer pruning. The statistical design was comprised of randomised blocks, using the pruning dates as treatment: 20 July, 4 August, 19 August, and 3 September (winter); 1 February, 15 February, 2 March, and 16 March (summer). Comparison of the mean values of GDD among pruning dates was evaluated by the Tukey test, and comparison between pruning seasons was made by the F test for orthogonal contrasts, both at the 5% probability level. The results showed good agreement between the values of GDD required to complete the cycle from the winter pruning until harvest when compared with other studies performed with the same cultivar grown in the Southern and Southeastern regions of Brazil. However, there was a consistent statistical difference between GDD computed for winter and summer pruning, which allowed us to conclude that this bio-meteorological index is not sufficient to distinguish vines pruned in different seasons and physiological phases applied in humid subtropical climates.

Examining the relationship between the Enhanced Vegetation Index and grapevine phenology

“…In our study, the grapevine growth profile differs in each year, with different peak greenness and growth rates. Maximum growth rate was consistent with the FLO stage, with growth reductions starting around VER, which is supported by previous research [Borghezan et al, 2012;Scarpare et al, 2012]. Altogether, the outcomes suggest that a slow-steady growth rate throughout the growing season can lead to longer phenological intervals, while rapid growth peaks tend to shorten the interphase.…”

Ethephon Sprays as a Defoliant in ‘Niagara Rosada’ Vine Subjected to Two Crop Production Per Year

“…Winter pruning is also known as dry pruning as plants are defoliated and the pruning is performed in the phase of reserve mobilization with a short pruning (with one or two buds) (SCARPARE et al, 2011).…”

“…This pruning is carried out in the summer, during the phase of reserve accumulation and is considered long, because the branches are pruned in the fourth or fifth bud (SCARPARE et al, 2011).…”

Desenvolvimento da videira 'Niagara Rosada' submetida a diferentes frequências de poda de produção em clima Cwa

“…Nesse ciclo de produção se realiza a poda curta, com uma ou duas gemas, e o desenvolvimento inicial da videira ocorre em época de baixa umidade relativa (UR) e temperaturas amenas; a maturação e a colheita dos frutos ocorrem em época de elevadas temperaturas e UR. É denominada poda seca, pois as plantas estão desfolhadas nessa época (SCARPARE et al, 2011). b) Poda de verão: também denominada poda verde, é realizada no verão na fase de acúmulo de reservas, com a colheita ocorrendo no fim do outono e início do inverno.…”

“…Neste ciclo de produção, ocorre alta UR e temperaturas elevadas no início do desenvolvimento das plantas e temperaturas amenas e baixas UR no período de colheita. É denominada como poda verde, pois as plantas apresentam-se enfolhadas na ocasião da poda (SCARPARE et al, 2011). Após a poda de produção foi aplicado nas gemas com auxílio de um pincel, solução de cianamida hidrogenada a 5% (produto comercial Dormex®).…”