Late defoliation of ‘Chardonnay’ grapevine in subtropical highland climate

ABSTRACT Chardonnay cultivar has shown great potential of planting and development in sites above 900m of Brazilian southeast for sparkling wines production. The quality of this product is related to vineyard climate and management, since both affect the vine development and grape composition. In this study, three defoliation orientations (east, west and east/west face), at veraison, and a group without defoliation, were compared in order to observe the impacts of this management on the productivity, grape and base wine quality. Yield, grape components, must and base wine composition were analyzed for two years. East/west defoliation increased alcohol content and decreased acidity in base wines, while the group without defoliation increased acidity, according to the higher and lower sun exposure, respectively. Defoliation at veraison increased the incidence of bunch rots. Differences in the aromatic composition of the base wines between the harvests were identified. The east/west defoliation treatment presented more intense fruity, citrus and tropical aromas. For regions characterized by subtropical highland climate (Cwb) in the Brazilian Southeast, late defoliation is not recommended since defoliated plants were more susceptible to fungus infection at flowering and berry formation.摘要 霞多丽（Chardonnay）葡萄品种在巴西东南部海拔900米以上的产区用于起泡酒酿造时，展现出优异的种植与发展潜力。该产品的品质与葡萄园气候及栽培管理措施密切相关，二者均会影响葡萄植株的生长态势与果实的成分构成。本研究设置转色期（veraison）的三种摘叶朝向处理（东向、西向及东/西双向），并增设无摘叶对照组，以探究该栽培管理措施对葡萄产量、果实品质及基酒品质的影响。研究连续两年对产量、葡萄果实成分、葡萄醪与基酒的组成进行了分析。结果表明：鉴于东/西双向摘叶组与无摘叶组的光照暴露程度分别较高、较低，东/西双向摘叶可提升基酒的酒精含量并降低酸度，而无摘叶组的基酒酸度则更高；转色期摘叶会增加果串腐烂的发生率。不同采收年份的基酒香气成分存在显著差异，其中东/西双向摘叶处理的基酒呈现出更为浓郁的果香、柑橘香与热带果香。针对巴西东南部属于亚热带高地气候（Cwb）的产区，不建议进行后期摘叶，因为摘叶后的植株在开花与浆果形成阶段更易遭受真菌侵染。