Vineyard management to improve fruit quality

Abstract

Purpose/Aim Understanding the influence of vineyard management on the developmental cycle of the grapevine is central to reaching a desired fruit quality. Too often than not, we focus on measuring harvest composition without a true in–depth understanding of how we get there. However, changes in composition over time are key to deepen our understanding of how management can improve fruit quality. We also have the added challenge of understanding how we can manipulate fruit quality through space and time. Seasonal differences and vineyard variability provide the foundations on which we can apply vineyard management strategies to improve fruit quality. This research explores how we can manipulate the source-sink balance of the grapevine via vineyard management to modify target berry composition in a cool climate environment. Methodology A range of different research trials are summarized which have considered the impact of source-sink manipulations on berry composition. These trials focus on relating these changes back to vine development and examining the consequences in the context of changing vineyard management, climate change and vineyard variability. Results Altering the source-sink ratio by different means, at different times and to different degrees via management techniques can result in a range of outcomes for quality. For example, removing leaves early in the season (bunch closure) has been shown to have a greater effect on delaying development than removing crop, although the interplay of these two techniques becomes confounded if they are applied at veraison. Furthermore, laterals which are considered sinks early in the season have an overall predominant contribution as sources, as they play an important role in driving berry composition during the ripening period. Through phenology modelling we can evaluate the delays and advances in development achieved by these canopy manipulations. Finally, we often investigate the impact of vineyard management to improve fruit quality in the context of average block values. When we consider individual vines in the vineyard, we can explore the variability in response to vineyard management, such as canopy manipulations or pruning. Conclusions Source-sink manipulations provide the viticulturist with a range of options to manipulate target berry composition and ultimately berry quality. However, the impact of site variability on the uniformity of composition also needs to be considered. Future work should consider the variation in response and its consequences on understanding the true impact of viticulture management practices to improve quality.