## 2 Results and Discussion
### Effects of Rootstocks on Vine Growth  
As shown in Table 1, all the ratios of rootstock to scion diameter in grafted vines were significantly lower than those in own-rooted vines, showing the swelling of the Cabernet Sauvignon scion with  
Figure 1: Meteorological data (monthly average temperature (**A**), sunshine duration (**B**), and rainfall (**C**)) of the experimental field from April to October in 2015–2016. respect to the rootstocks at the graft joint. The swelled scion above the graft union was also found in a previous study [7]. Pruning weight is an indicator of shoot vigor [11], and the pruning weight of vines in 2015 was significantly higher than that in 2016, indicating that vines grew mature over the years. Besides, the effects of season on vine pruning weight far outweighed any difference in pruning weight due to the rootstocks. In this study, no significant differences in pruning weight were observed among grafted and own-rooted vines (Table 1), which is in agreement with a previous study [9]. Contrarily, some studies have reported that rootstocks imparted a statistical influence on vine pruning weight [1; 2; 3; 4; 5; 6]. The vigor control mechanisms of different rootstocks are complex. In addition, rootstock effects on vine pruning weight can be modified by vintage, rootstock genotype, scion cultivars [11; 22] and soil condition (water supply, acidity, macro-element level) [4; 7; 12]. Notably, own-rooted vines produced the lowest pruning weight in this study, and there were tendencies for rootstocks to confer increased vigor on the scion (Table 1). Similar results were reported in the previous study in which [PERSON] own-rooted vines possessed the least vine vigor (pruning weight) in comparison with five grafted vines [7]. Through transcriptome analysis of the shoot apex collected from the hetero-grafted and auto-grafted Cabernet Sauvignon vines, [PERSON] et al. [8] revealed that rootstocks triggered the up-regulation, rather than down-regulation, of gene expression in hetero-grafted vines. Besides, many genes from major and minor carbohydrate metabolism and sugar transporters were differentially regulated in hetero-grafted grapevines, which may alter the effectiveness of carbon transportation. Annual variations dominated the variations in yields; specifically, the average yield in 2016 was significantly higher than that in 2015. Rootstocks had no significant effects on yields (Table 1). In previous studies, there were no consistent conclusions for the influence of rootstocks on yields [1; 2; 3; 5; 6; 15; 16; 23]. Rootstocks can give rise to different reactions to yield formation in different types of soil, and it was reported that yields of different grafted vines only significantly differed in shale soil when compared to granite soil [13]. Overall, the influence of rootstocks on yields may depend on seasons, scion cultivars, and soil types. Notably, in this study, own-rooted vines showed the highest yield in comparison with the other graft combinations (Table 1). [PERSON] et al. [11] also found that own-rooted vines produced lower yields than grafted vines in one of three seasons. The vine yield to pruning weight ratio (crop load) is generally used to determine whether a grapevine is balanced. It was estimated that the crop load of balanced vines ranges between 4 and 10 [17]. In this study, seasonal effects contributed to the dominant variations in crop load, which