## 3 Results and Discussion
### Berry Composition
Besides the differences in Brix, SST did not significantly affect other berry composition variables compared to HC, confirming the previously reported findings from several authors that, if the severe shoot trimming or apical leaf removal is performed at late veraison, it does not negatively affect the phenolic composition of berries [28; 31; 32; 35; 50; 37]. On the other hand, due to more advanced ripening CT decreased titratable acidity and increased pH of grape juice in both years; this effect is often obtained with this practice [1; 12; 13; 14]. Concerning the berry phenolic composition, cluster thinning only significantly increased the total anthocyanins expressed as mg per berry in 2017, though the concentration of total anthocyanins (expressed as mg/g) had a tendency to increase with reduced crop size in both years. This effect presumably stems from the increased sugar concentration in berries of CT treatment as sugars, together with abscisic acid, are thought to trigger the biosynthesis of anthocyanins in grape berries [51; 52]. In other studies, the effect of cluster thinning on the concentration of total anthocyanins in berries differs according to the growing conditions and ranges from no impact to a major positive impact. The final \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c c} \hline \hline  & \multicolumn{8}{c}{**Season 2017**} & \multicolumn{8}{c}{**Season 2018**} \\ \cline{2-13}  & \multicolumn{3}{c}{**Cluster Thinning**} & \multicolumn{3}{c}{**Shoot Trimming**} & \multicolumn{3}{c}{**Int. b**} & \multicolumn{3}{c}{**Cluster Thinning**} & \multicolumn{3}{c}{**Shoot Trimming**} & \multicolumn{3}{c}{**Int.**} \\ \cline{2-13}  & **FC** & **CT** & **Sign. a  & **HC** & **SST** & **Sign.** & **Sign.** & **FC** & **CT** & **Sign.** & **HC** & **SST** & **Sign.** & **Sign.** \\ \hline Soluble solids & 21.7 & 22.8 & *** & 22.9 & 21.6 & *** & * & 22.3 & 23.5 & ** & 23.5 & 22.3 & ** & * \\ Titratable acidity (g/L) & 7.0 & 6.4 & *** & 6.6 & 6.8 & ns & ns & 6.8 & 6.4 & * & 6.7 & 6.5 & ns & ns \\ pH & 3.40 & 3.49 & *** & 3.46 & 3.42 & ns & ns & 3.42 & 3.56 & ** & 3.49 & 3.49 & ns & ns \\ Total anthocyanins & 0.75 & 0.83 & ns & 0.80 & 0.79 & ns & * & 0.73 & 0.79 & ns & 0.78 & 0.75 & ns & ns \\ Total anthocyanins & 0.91 & 1.07 & * & 1.03 & 0.95 & ns & ** & 1.04 & 1.20 & ns & 1.14 & 1.11 & ns & ns \\ Total phenolics (mg/g) & 1.72 & 1.76 & ns & 1.72 & 1.76 & ns & ns & 1.58 & 1.61 & ns & 1.60 & 1.58 & ns & ns \\ Total phenolics & 2.09 & 2.23 & ns & 2.22 & 2.11 & ns & ** & 2.25 & 2.43 & ns & 2.33 & 2.36 & ns & ns \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Berry composition of Merlot vines subjected to cluster thinning (FC—full crop; and CT—cluster thinning) and shoot trimming (HC—high canopy; and SST—severe shoot trimming). Figure 2: Sugar content in berries (mg/berry) during ripening in 2017 and 2018 seasons. FC-HC—full crop combined with high canopy; FC-SST—full crop combined with severe shoot trimming; CT-HC—cluster thinning combined with high canopy; CT-SST—cluster thinning combined with high canopy; CT-SST—cluster thinning combined with severe shoot trimming. Data were analyzed via one-way ANOVA in randomized blocks design (ns, not significant; \({}^{\star}\), \(p\leq 0.05\); \({}^{\star\star}\), \(p\leq 0.01\)). Different letters at same sampling date indicate significantly different means. outcome is mostly affected by the assimilate availability for the developing berries before the execution of cluster thinning; vines which experience greater limitation in assimilate availability generally obtain more benefits from cluster thinning in terms of improved berry ripening, greater accumulation of assimilates in the berries and higher berry and wine quality [11; 12; 53; 54]. For some berry composition variables, the interaction between the two investigated factors was obtained (Table 2) and, in these cases, the results of all specific combinations of treatments were presented in order to elucidate the effects of the particular combinations (Figure 3).