Shading of the fruit zone to reduce grape yield and quality losses caused by sunburn

• Published in: OENO one Vol. 48; no. 3; pp. 179 - 187
• Main Authors: Manuel Oliveira, José Teles, Pedro Barbosa, Francisco Olazabal, Jorge Queiroz
• Format: Journal Article
• Language: English
• Published: International Viticulture and Enology Society 30.09.2014
• Subjects: excessive radiation; must characteristics; Vitis vinifera; yield components
• ISSN: 2494-1271
• DOI: 10.20870/oeno-one.2014.48.3.1579

Aim: To test the hypothesis that shading of the fruiting zone of the plants might reduce yield losses caused by excessive exposure to sun while avoiding the most damaging effects associated with reduced radiation. Methods and results: A number of grapevine rows were shaded with a double layered white plastic netting on their south-facing side, from the ground to about 20 cm above the cluster zone. Data on meteorological conditions, plant growth, plant water availability, yield components and must characteristics were recorded during three growing seasons. Shading significantly increased yield but did not alter significantly the must characteristics. Conclusion: Partial shading of the grapevine canopy reduced yield losses attributable to excessive radiation. The must obtained from shaded berries had a lower concentration of anthocyanins, and the wines made from these musts had a lighter colour which may be detrimental to their quality. Significance and impact of the study: The study highlights the effects of solar radiation on the composition of grape musts and suggests a potentially cost-effective method to control excessive radiation in vineyards.