## 2 Results and Discussion
### Effects of Rootstocks on Berry Volatile Compounds
Notably, 101-14 statistically enhanced (\(E\))-\(\beta\)-damascenone concentrations in mature grape berries in two consecutive seasons. Since (\(E\))-\(\beta\)-damascenone was the most abundant C\({}_{13}\)-norisoprenoid in grape berries, significantly higher concentrations of total C\({}_{13}\)-norisoprenoids were also observed in CS/101-14 compared to those in CS at harvest (Figure 4a). There were 23 biomarker volatile compounds identified through O2 PLS-DA to separate CS/110R from CS (Supplementary Table S3). Among these compounds, 110R had a negative influence on the concentrations of total esters, which were lower in CS/110R than those in CS at E-L 37 and 38 stage. In addition, despite the fact that 110R had an inconsistent influence on the concentrations of (\(E\))-\(\beta\)-damascenone and D-limonene before harvest in the two seasons, it significantly increased the concentrations of (\(E\))-\(\beta\)-damascenone and D-limonene in mature grape berries (Figure 4b). The O2 PLS-DA analysis revealed that 30 volatile compounds were responsible for the separation between CS/5 BB and CS (Supplementary Table S3). 5 BB showed a consistent positive influence on the accumulation of benzeneacetaldehyde, (\(E\))-\(\beta\)-damascenone, total C\({}_{13}\)-norisoprenoids, and nerol oxide in the two seasons (Figure 4c). With the first filtering of VIP > 1.0 in the O2 PLS-DA model of CS/SO4 vs. CS, 24 volatile compounds were screened (Supplementary Table S3). Among these compounds, total esters and \(\gamma\)-terpinene were consistently affected by SO4. Particularly, SO4 tended to inhibit the accumulation of total esters after E-L 36 stage. The concentrations of total esters in CS/SO4 were statistically lower than those in CS at harvest in the two seasons (Figure 4d). In agreement with our results, [PERSON] et al. [19] also reported that SO4 caused a reduction in ester content compared to own-rooted 'Summer Black'. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**O2 PLS-DA Models** & **Components \({}^{\star}\)** & \(R^{2}X\) (cum) & \(R^{2}Y\) (cum) & \(Q^{2}\) (cum) & \(p_{\text{CV-ANOVA}}\) & \multicolumn{2}{c}{**500 Permutation Tests**} \\ \cline{5-8}  & & & & & & \(R^{2}Y\) Intercept & \(Q^{2}Y\) Intercept \\ \hline CS/101-14 vs. CS & \(1+6\) & 0.94 & 0.78 & 0.61 & \(4.31\times 10^{-5}\) & 0.39 & \(-0.67\) \\ CS/110R vs. CS & \(1+5\) & 0.91 & 0.86 & 0.72 & \(5.07\times 10^{-10}\) & 0.36 & \(-0.63\) \\ CS/5A vs. CS & \(1+2\) & 0.92 & 0.52 & 0.38 & 0.09 & 0.20 & \(-0.29\) \\ CS/5 BB vs. CS & \(1+7\) & 0.92 & 0.90 & 0.81 & \(3.35\times 10^{-13}\) & 0.43 & \(-0.83\) \\ CS/damin 1 vs. CS & \(1+6\) & 0.93 & 0.84 & 0.74 & \(1.00\times 10^{-9}\) & 0.40 & \(-0.71\) \\ CS/Harmony vs. CS & \(1+2\) & 0.93 & 0.51 & 0.32 & 0.28 & 0.21 & \(-0.30\) \\ CS/Riparia Gloire vs. CS & \(1+8\) & 0.93 & 0.91 & 0.68 & \(4.03\times 10^{-7}\) & 0.48 & \(-0.99\) \\ CS/SO4 vs. CS & \(1+6\) & 0.94 & 0.94 & 0.87 & \(1.46\times 10^{-14}\) & 0.41 & \(-0.81\) \\ \hline \hline \end{tabular} \({}^{\star}\) representative of numbers of predictive components plus orthogonal components.  
\end{table} 
Table 3: Validation of O2 PLS-DA models on volatile compounds in berries for the comparison of each grafted vine and own-rooted vine. In addition, despite the fact that SO4 played a negative role in the accumulation of \(\gamma\)-terpinene and \(\alpha\)-terpineol before harvest, no significant differences in the concentrations of \(\gamma\)-terpinene and \(\alpha\)-terpineol between CS/SO4 and CS were found at harvest. The concentrations of total terpenids were decreased by SO4 after E-L 31 stage; besides, significant decreases were found at harvest (Figure 4d). The O2 PLS-DA model of CS/Ganzin 1 vs. CS revealed that 22 volatile compounds highly contributed to the separation between CS/Ganzin 1 and CS (Supplementary Table S3). Through screening those compounds consistently impacted by CS/Ganzin 1 in the two seasons, the accumulation of (\(E\))-\(\beta\)-damascenone and total C\({}_{13}\)-norisoprenoid was promoted by CS/Ganzin 1 (Figure 4e).