Modulation of Berry Size and Composition by Canopy Management in Sprawl-Trained Grapevines Grown Under Warm Climate Conditions

Canopy microclimate is largely determined by canopy architecture, including the amount and spatial distribution of leaf area, and its interaction with environmental conditions. In warm Mediterranean climates, training systems that promote a more open canopy structure can improve light penetration, air circulation, and the physiological performance of leaves and berries. This study evaluated the effects of canopy architecture on berry development and fruit composition in Vitis vinifera L. cv. Tempranillo, under warm and dry conditions. The objective was to determine how canopy management influences the cluster zone microclimate and, consequently, affects berry weight and size (diameter), must composition (total soluble solids-TSS, pH, acidity and yeast-assimilable nitrogen) and berry skin composition and properties (polyphenol content, anthocyanin profile, color intensity and hue index), particularly under warm Mediterranean conditions. To test this, two training systems were evaluated in a commercial vineyard: a vertical shoot position (VSP) and a sprawl (SP), under the same crop load and irrigation regime. The results indicate that the sprawl system had some differences in berry weight/diameter (6–8%), resulting in slightly more advanced ripening at veraison, as evidenced by a tendency toward higher TSS levels and, most notably, by increased concentrations of yeast-assimilable nitrogen (α-amino nitrogen and ammonium; +31%) compared to VSP. In addition, SP berries exhibited higher anthocyanin concentration than VSP, particularly in Malvidin-3-O-cumaril-glucoside-trans (+24% higher concentration) in the berry skins. These variables represented the most consistent and oenologically relevant differences between the two training systems. Overall, the findings support the adoption of sprawl canopies as a practical strategy to mitigate the negative effects of high temperatures on grape composition in Mediterranean viticultural regions.