Phenological and thermal demand (degree-days) characterization of Cabernet Sauvignon grape, cultivated in subtropical zones

Abstract

The aim of this research was to characterize the phenological performance of Cabernet Sauvignon grape (Vitis vinifera L.) produced in the northwest of Parana State, as well as to characterize its thermal demand on degree-days. The experimental area was established in a commercial vineyard of Vinícola Intervin^®, Maringá, State of Paraná. The vineyard was planted in August, 2000 and the trees were cultivated in pergola system, with 4.0 x 1.5 m spacing. The evaluations started from the winter pruning of 2003. Random design was used as statistical model, with 20 replications and each plot was composed by one tree. The grapes phenology was evaluated considering the duration in days for each one of the following subperiods: pruning to bud swell, pruning to beginning of shot growth, pruning to visible cluster, pruning to flowering, pruning to early ripening and pruning to harvest. The thermal demand of Cabernet Sauvignon grape was determined using the degree-days sum from pruning to harvest, as well as for each subperiod, considering two base-temperatures (10ºC and 12ºC). Results showed that Cabernet Sauvignon grape cycle (pruning to harvest) in northwest of Parana takes 126 days, and its thermal demand is 1,221.25 degree-days. The most suitable base-temperature to calculate this demand was 10ºC.