Reshaping grapevine canopy management under climate change scenarios: the role of conservative summer pruning on leaf physiology, berry microclimate, wine aromatic and sensory profile

Canopy management in viticulture involves key agronomic practices aimed at balancing the leaf-to-fruit ratio and optimizing microclimates for leaves and bunches. In temperate-to-cool regions, intensive green pruning is essential for effective crop protection and aroma development. However, rising temperatures and stress conditions are prompting a re-evaluation of these practices to mitigate negative impacts from overexposed bunch-zones such as sugar accumulation, acidity loss, sunburn, anthocyanin degradation, and reduced vine longevity. This study explored alternative, more conservative green pruning methods in Guyot-trained Cabernet Franc and Nermantis (a pathogen-resistant hybrid) over two years to: i) reshape berry and leaf microclimate, ii) evaluate berry quality, and iii) assess wine aroma and sensory characteristics. Significant differences emerged between minimal and intensive canopy management strategies. Reduced intervention led to: 1) lower canopy porosity and bunch light exposure; 2) reduced leaf photoinhibition; 3) cooler berry temperatures; 4) better sugar-acid balance at harvest; and 5) higher anthocyanin levels. These effects held across contrasting seasons—2022 (hot, dry) and 2023 (cool, wet)—though driven by different putative mechanisms: differences in berry microclimate in 2022 and unbalanced leaf-to-fruit ratio in 2023. While wine chemistry showed little variation, aroma profiles were clearly affected. However, sensory analysis revealed varietal sensitivity, with Cabernet Franc more responsive than Nermantis, especially for aroma. Assuming summer pruning as a critical operation in the context of grapevine crop protection, the possibility to exploit the potential inherently higher tolerance to fungal pathogens of hybrid varieties is discussed