Vegetative, Yield, and Berry Quality Response of Aglianico to Shoot Trimming Applied at Three Stages of Berry Ripening

Abstract

The rise in air temperature due to climate change is causing an increase in sugar accumulation rate in the grape berries and this is resulting in an increase in wine alcohol concentration. Post-veraison leaf area removal (defoliation, shoot trimming) is a suitable canopy management strategy to slow down carbohydrate accumulation in the berries. However, in late-ripening cultivars, the phenological stage between veraison onset and harvest can be very long. Therefore, it can be hypothesized that the specific timing when leaf area removal is applied during this stage can affect differently carbohydrate accumulation in the berries having a different impact on berry composition. Therefore, a two-year experiment was designed to compare the responses of Aglianico grapevines, a late-maturing cultivar, to shoot trimming applied at three different stages of berry ripening. The experimental design included: (a) three trimming treatments applied at total soluble solids of 6, 12 and 18 Brix, respectively; and (b) a control treatment (untrimmed vines). Independently of the application timing, shoot trimming decreased berry total soluble solids at harvest compared to control vines, but the later the shoot trimming was applied, the lower was berry total soluble solids at harvest. Shoot trimming did not affect other parameters of berry. These results confirm that, at least for late-maturing cultivars, the timing of application of late shoot trimming plays a key role in modulating the intensity of the effects of this management practice on berry composition.