Climate change and vine training systems: the influence different spatial distribution of shoots may have on sugar accumulation in Sangiovese grapevines.

Department of Agricultural and Food Sciences DISTAL – University of Bologna, Viale Fanin 44, Bologna, Italy

^* Corresponding author: gabriele.valentini4@unibo.it

Abstract

The choice of training system may influence vineyard efficiency in terms of light interception and water consumption, particularly in the current context of climate change. On this basis, during the 2017 season, Sangiovese potted vines were grown outdoors using two different training systems: guyot vertical shoot positioned system (C) and V-shaped open canopy (A). From the end of June until September, vine transpiration was continuously monitored by the gravimetric approach and at different times in the season, the leaf area, light interception, photosynthetic activity and stem water potential were measured. Grape yield and fruit composition were recorded at harvest. C plants did not differ from A in terms of leaf area during the entire season. Light interception was higher in C vines during the early hours of the morning and lower in the central part of the day and the transpiration loss was higher, as was the net photosynthesis detected on some days in August. No differences were detected in terms of yield but a significant increase in soluble solids was found in C compared to A. The open canopy compared to a closed one, in a particularly hot year like 2017, resulted in negative consequences on the accumulation of soluble solids, probably as a result of the radiative stress suffered by the A vines in the middle hours of the day.