2017 ASHS Annual Conference

Cold-climate wine grape cultivars with Vitis riparia parentage, released since the mid-1990s, have created new and rapidly expanding grape and wine industries in the Northeast and Upper Midwest of the United States. However, one of the main viticultural challenges of growing Vitis riparia hybrids in cold climate regions is achieving desirable fruit quality at harvest. Cold winter temperature, short growing season, low accumulation of heat units, heavy rainfall during fruit ripening season, and fall frost are all characteristics of grape growing conditions in Wisconsin that result in delayed fruit maturity and produce low quality fruit that is not suitable for quality wine production. Canopy management, defined as a range of techniques that modify the position and number of shoots and fruit spacing, with the objective of modifying the microclimate of the canopy, can be used to increase the consistency of ripe fruit production. This research investigated the impact of post bloom basal leaf removal in the 2015 and 2016 growing seasons in Wisconsin. Experiments were conducted at the West Madison Agricultural Research Station (WMARS) in Verona, Wisconsin. Using ‘Marquette’, ‘Frontenac’, ‘La Crescent’, and ‘Brianna’ vines, yield components and fruit composition traits (total soluble solids (TSS), pH, titratable acidity (TA), malic and tartaric acid composition and glucose and fructose concentration) were evaluated to investigate the impact of basal leaf removal on fruit quality during the ripening period of cold hardy wine grape cultivars. Basal leaf removal treatment increased cluster and berry light exposure, berry temperature, and TSS accumulation. In addition, basal leaf removal resulted in a decrease TA concentration, mainly driven by a decline in malic acid concentration. Basal leaf removal is a promising canopy management practices that can improve fruit quality of cold hardy wine grape cultivars grown in cold climate regions.