Exploration of the effects of fruit and berry exposure on fruit composition in Vitis vinifera cv. Pinot Noir

The maintenance and improvement of quality of Pinot Noir table wines has been highlighted as a key factor in the development of the Tasmanian wine industry. This study was designed to further investigate the cultural and environmental impacts on the composition of Pinot Noir fruit in a cool climate. Over three vintages, 2005, 2006 and 2007, the industry practice of pre-veraison leaf removal in the fruiting zone is investigated. Defoliation was shown to delay ripening and this study provides evidence that the environmental influence over the entire season may have more impact on fruit composition, than increased fruit exposure or source/sink relationships during berry ripening. The impact of bunch exposure on fruit composition was investigated in 2007 by imposing a range of shading and light exclusion treatments. Results support the conclusions of previous authors that biosynthesis of anthocyanin occurs independently of carbohydrate metabolism. The impact of bunch compactness on the composition of Pinot Noir is investigated over two growing seasons by manipulation with pre-bloom application of Giberrellic Acid (GA3). Observations suggest that a reduction in bunch compactness, lead to an improvement in grape composition, including higher anthocyanin concentration, in one of two experimental seasons. An argument for a relationship between increasing berry size and reduced total anthocyanin in Pinot Noir is presented