Effects of grapevine canopy leaning on grape composition and wine quality of ‘Bobal’

Abstract

Exploring new field strategies for adapting winegrowing regions to the adverse effects of climate change becomes imperative. This study focuses on the effects of canopy architecture through the trellis systems leaning of North–South oriented vineyard’s rows vertical shoot positioned (VSP) system by 30° towards either the East (ESP) or the West (WSP) as a possible adaptation technique. The trial was conducted over two seasons in a Vitis vinifera L. cv. Bobal vineyard located in Requena (Valencia), eastern Spain, under a temperate-warm climate. The canopy leaning was considered to affect the radiation load and its timing with potential effects on vine physiology and grape metabolism and, consequently, on grape and wine quality. Leaning treatments affected vegetative growth, likely due to slight differences in vine water status. In comparison to VSP and ESP, WSP intercepts more light in the morning, when the photosynthetic capacity of the vines is at its highest. However, this results in a more negative vine water potential, which in turn leads to a reduction in vigour with no impact on yield. Musts from the WSP showed a tendency to increase total acidity compared to VSP, while ESP tended to decrease it. This was likely due to the reduction in temperature within the cluster microclimate in WSP in comparison to the ESP and VSP treatments. In addition, musts from the WSP treatment showed higher colour intensity, anthocyanins and polyphenols, potentially attributable to its more negative potentials, likely due to its more negative potentials, which may have prompted the synthesis of phenolic compounds. Consequently, wines from the WSP treatment displayed higher total acidity and lower pH, as well as higher colour intensity, anthocyanins, and polyphenolic content. In addition, WSP wines had higher concentrations of esters and higher alcohols. The improvements in grape and wine composition are likely due to an increased cluster radiation interception in the morning and reduced heating in the afternoon when VPD is higher. Our findings demonstrate that canopy management by leaning VSP vines towards the West can be a useful technique for adapting grape and wine composition to climate change and provide insights into its physiological basis.

Keywords

• Aroma compounds
• cluster microclimate
• canopy management
• polyphenolic composition
• radiation load
• vine physiology