Physiological Responses of Cabernet Sauvignon to Dividing Canopies in the Chihuahuan Desert

Canopy architecture is fundamental to productivity in grapevines. This research focused on evaluating the impact of opening canopies on the capture of photosynthetically active radiation, photosynthetic activity, and berries’ physicochemical properties in Cabernet Sauvignon grapevines. A completely randomised design was used to compare open and closed canopies, with ten replicates per treatment (20 vines in total), during the vegetative growth period and after harvest. The key measurements included photon flux density (PFD), daily light integral (DLI), photosynthetic rate (PR), stomatal conductance (SC), intercellular CO2 concentration (IC), leaf area (LA), transpiration, ambient CO2 concentration, and temperature. Additionally, we assessed berry quality variables, such as total soluble solids (TSS), glucose/fructose ratio, total titratable acidity (TTA), pH, TSS/TTA, and total phenols (TP). During vegetative growth, PFD, DLI, PR, IC, and LA increased significantly (p ≤ 0.05), whereas after harvest, only PR and IC showed variation Closed canopies increased water use efficiency (CO2/H2O) by 62.5%, while the temperature was higher in open canopies. Opening canopy increased contacts, gaps and visible sky and reduced leaf area index. Berries from open canopies showed higher TSS, glucose-fructose, pH, TSS/TTA and TP contents. Opening canopy is essential for improving light interception, photosynthetic efficiency, and fruit quality in Cabernet Sauvignon grapevine cultivated in northern Mexico.