Using delayed winter pruning to prevent spring frost damage in 'Chardonnay' cultivar

摘要

'Chardonnay' is an early cultivar, that can be damaged by early spring frosts. In this sense, agronomic practices are necessary to protect the plants without causing losses in plant productivity and grape quality. The objective of this study was to investigate the effect of delayed winter pruning on the phenology and yield components of 'Chardonnay' grapevines. The experiment was conducted in Villaggio Grando Winery (26°43'92"S, 51°30'72"W, altitude 1,350 m) located in Agua Doce, Santa Catarina State. Vines were trained in vertical shooting positioning trellis and spacing 2.9x1.5 m. The experimental design was completely randomized with four pruning dates, five replications and ten plants per replication. The pruning dates were August 25th (as control) and 31st; September 8th and 15th. The phenology was evaluated until inflorescence clearly visible stage. At harvesting time, the yield components, such as cluster per vine, cluster weight, yield (kg plant1 and t ha1), were evaluated. Grape qualitycomponents were also evaluated (soluble solids, titratable acidity and pH). In general delay of pruning in 'Chardonnay' delays plant phenological circle as well as the grape ripening. Pruning made within seven days of delay with respect to the control date, may be performed in locations which present risks of spring frosts occurrence. However, pruning made later than one week after the control date, may lead to yield losses up to 58%.