## 3 Results and Discussion
### Aroma Components Analysis  
The volatile compounds in each developmental stage are shown in Figure 3A. In this experiment, a total of 62, 62, 61, 60 volatile compounds were identified from CK, T1, T2, and T3 training systems, respectively (Table S5). We classify these volatile compounds in grape berry into ten kinds, and C6/C9 compounds kept the most abundant free compounds during all stages; the C6/C9 compounds are synthesized by the LOX and HPL synthetic pathway, and mainly present 'grassy' and 'green' flavors [24], as shown in Figure 3A. The contents of C6/C9 compounds rose after 65 DAA and turned to a downward trend immediately; this is because the sugar began to accumulate concurrently, and the free volatile compounds transformed into bound volatile compounds under glycosylation, but some researchers have indicated that volatile evolution is not proportional to the changes in the sugar content of grapes in neutral varieties [25]; otherwise, in the LOX pathway of 'Shine Muscat', LOX, ADH, and substrate alcohols were the limiting factors for the corresponding reactions [26]. Curiously, the C6/C9 compounds under T3 treatment maintain the highest content at harvest, which is 2253.67 \(\upmu\)g/L. We conjecture that the canopy temperature and microclimate were better in T3 treatment (high light/low humidity). The second-highest content compounds are carbonyl compounds, which shows rising with the development of berries. Among them, the T2 treatment has the highest content at harvest. The higher alcohols exhibited the highest content under T3 treatment at harvest, and the rate of conversion from aldehyde to alcohol is strongly related to the activities of these enzymes, which is dependent on variety or Vitis species [27]. Norisoprenoids and terpenoids had low concentrations in Cabernet Gernischt berries in the whole growth period, but they make important contributions to the characteristic varietal aroma, owing to their extremely low odour thresholds [28]. Compared with other fruits, the aroma characteristics of grape berries are characterized by terpen, especially monoterenes, which primarily result in a rich rose aroma, and sharply decreased from the fruit-set to the veraison period [26]. Similar results were found in this study; linalool, \(\alpha\)-terpineol, \(\beta\)-citronellol, geraniol, and myrcene belong to monoterenes, and the contents of terpen increase slightly during the growth period. However, in non-aromatic grapes, what is more important is the reduction of isoprene substances, which are also characterized by flower and fruit aromas. Temperature is a key factor affecting the physiology of wine grapes, which have regulation effects on C\({}_{13}\)-norisoprenoids via the influence of the cycle growth of the grape [29]. It was found that, under the condition of higher temperature, the contents of \(\beta\)-damascone, \(\beta\)-ionone, and \(\alpha\)-ionone in wine were higher [30], so that the high temperature during the growth period and the large temperature difference between day and night in Ningxia may be the reasons for the high content of C\({}_{13}\) in this area. Moreover, the T1 and T2 treatments contain more C\({}_{13}\)-norisoprenoids; we speculate that leaves can accept more light under this treatment, which result in changes to the canopy microclimate [31]. For _VvEcar_ involved terpenoid synthesis, its present highest level is 50 DAA and declines after veraison, and it gradually becomes higher at 120 DAA. _Vvter_ regulates \(\alpha\)-terpineol synthase expression at the transcriptional level; similar to _VvCCD1_, the expression level is the lowest at veraison, and tends to rise from 70 DAA to 120 DAA; the T3 treatment was kept at its highest level at harvest. _VvLis_ is a key gene in the late phase of the monoterene anabolic pathway; the expression level is the highest at young grape berries and rapid decline, otherwise, it rises at 70 DAA and the T3 treatment is kept at its highest level.