## 3 Results and Discussion  
### General Properties  
Visual appearances of Shine Muscat grapes treated with different levels of berry thinning are shown in Figure 1 and their color coordinates are presented in Table 1.  
L values were not different among the sample groups. The \(a\) values of BT30 and BT50 were lower than those of BT0. This result indicates that berry thinning decreased the greenness of the berry skin color resulting from the acceleration of berry ripening. On the other hand, the \(b\) value of BT50 was higher than those of BT30 and BT0. The increase in the \(b\) value indicates the color change of berry skin from green to yellowish green due to the accumulation of carotenoids [2].  
The effects of berry thinning on the TSS, TA, and TSS/TA ratio are presented in Figure 2. Berry thinning increased the TSS and decreased TA in Shine Muscat grapes. Both BT30 and BT50 groups showed higher TSS and lowered TA than the control group (BT0). Furthermore, TSS and TA were affected by the level of berry thinning. Specifically, The BT50 group had higher TSS and lowered TA than the BT30 group. The ratio of TSS to TA (TSS/TA) tended to increase due to the increasing trend of TSS and decreasing trend of TA with increasing the level of berry thinning. A previous study by [PERSON] et al. [8] showed that selective berry thinning of Refosco dal peduncolo roso (_V. vinifera_ L.) grapes increased TSS. However, it showed no changes in TA or pH. [PERSON] et al. [19] reported that berry thinning increased the TSS of Merlot grapes, but had little effect on Cabernet Sauvignon grapes. It was assumed that the berry thinning treatment accelerated the ripening of the grape berries because the changes in TSS and TA are good indicators of the ripeness  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Level of Berry**} & \multicolumn{3}{c}{**Color Coordinates**} \\ \cline{2-4}
**Thinning (BT, \%)** & **L** & \(a\) & \(b\) \\ \hline
0 & 37.04 \(\pm\) 1.91 \({}^{\text{a}}\) & \(-\)6.67 \(\pm\) 0.33 \({}^{\text{a}}\) & 11.67 \(\pm\) 0.76 \({}^{\text{b}}\) \\
30 & 37.74 \(\pm\) 1.31 \({}^{\text{a}}\) & \(-\)6.3 \(\pm\) 0.20 \({}^{\text{b}}\) & 11.63 \(\pm\) 0.48 \({}^{\text{b}}\) \\
50 & 37.97 \(\pm\) 0.73 \({}^{\text{a}}\) & \(-\)6.45 \(\pm\) 0.27 \({}^{\text{a}\text{b}}\) & 12.41 \(\pm\) 0.32 \({}^{\text{a}}\) \\ \hline \hline \end{tabular}  
* Means with different letters within the same row are significantly different at \(p\) < 0.05.  
\end{table}
Table 1: Effects of berry thinning on the skin color indices of Shine Muscat grapes.  
Figure 1: Effects of berry thinning on visual appearances of Shine Muscat grapes: BT0, BT30, and BT50 indicate the level of berry thinning in terms of percentage.  
of grapes. Thinning can provide thinned berries more opportunities to access enough nutrients compared to untreated ones, resulting in the acceleration of berry ripening [6].  
The effects of berry thinning on the size and weight of Shine Muscat grapes are shown in Figure 3. The horizontal diameter showed no differences between BT0 and BT30, but BT50 was lower. On the other hand, the vertical diameters of BT30 and BT50 were higher than those of BT0. The cluster weight tended to decrease with increasing level of berry thinning. The average cluster weight was 1034, 825, and 524 g for BT0, BT30, and BT50, respectively. However, the weight of individual berries was not affected by thinning treatment, although [PERSON] et al. [20] found that berry thinning increased both berry size and weight of Crimson Seedless grape berries.  
Figure 3: _Cont_.  
Figure 2: Effects of berry thinning on the total soluble solids content, titratable acidity, and Brix/TA of Shine Muscat grapes.