Double-pruning of ‘Syrah’ grapevines: a management strategy to harvest wine grapes during the winter in the Brazilian Southeast

Abstract

Grape harvest in the major grapevine growing regions of Brazil occurs during the summer; a period with excessive rainfall. The climatic conditions during the Brazilian summer can have an adverse effect on fruit maturation and wine quality. This study compared the performance of 'Syrah' grapevines cultivated in two growing seasons. A double pruning management system was employed as a technique in the vineyard and the grapevines were cultivated in summer, a cycle normally adopted in the South and Southeast of Brazil and winter during 2005 and 2006 in a non-irrigated vineyard. Vine water stress was minimal for both growing seasons and photosynthetic rates were found to be lower in the winter than the summer. However, no differences in vegetative vigor were observed. The growing season was shorter in summer than in winter. This was predominately due to a faster ripening period in the summer. During the winter harvests, grapevines had a higher yield, accumulation of sugar, anthocyanins and total phenolic compounds, and the lowest rot incidence. Double-pruning proved to be a powerful tool to improve wine grape composition in the Brazilian Southeast. This management will allow the production of quality raw materials for the production of good wines, allowing Southeastern Brazil to enter the competitive globalized wine market.