# Rootstock Effect on Volatile Composition of Albarino Wines
## 3 Results and Discussion  
### Chemical Composition of Musts  
The yield components and chemical composition of _V. vinifera_ cv Albarino grafted on nine different rootstocks (110R, SO4, 196-17C, Riparia G, 161-49C, 420A, Gravesac, 3309C and 41B) were evaluated during two consecutive vintages (Table 2). It is known that rootstocks affect plant size and plant vigor and consequently the crop load [3]. In addition, the rootstock effects can be modified by vintage cultivar genotype and soil condition [17]. In this study, there were tendencies for rootstocks to confer increased vigor on the scion in 2010 vintages, where increases of clusters per vine, cluster mass and, therefore, yield were observed. From rootstocks, a trend to increase the yield for 161-49C and 41B was observed in the 2009 vintage; however, those were Gravesac, 41B, Riparia Gloria, 110R and SO4 in 2010. On the other hand, plant vigor influenced the leaf exposure to the sun and the proper fruit ripening, i.e., sugar accumulation. It can be seen that the \({}^{\circ}\)_Brix_ at the harvest date of 2009 is slightly higher compared to the harvest date 2010. Moreover, the 2009 vintage had higher pH musts and higher contents of tartaric acid. However, the total acidities of the musts from vintage 2009 were lower compared to the musts from vintage 2010. Both vintages had similar content in malic acid. Tartaric acid and malic acid are the major grape acids; moreover, tartaric acid is characteristic of _Vitis vinifera_. In terms of sugar accumulation, as \({}^{\circ}\)_Brix_ value, the range registered for 2009 vintage was higher than 2010. A trend to reaching higher \({}^{\circ}\)_Brix_ was shown for 196-17C (24.8) and 161-49C (22.6) in 2009 and 2010, respectively. In contrast, a tendency to achieve lower values was observed for 420A (22.7) in the 2009 vintage and SO4 (21.5) in the 2010 vintage. Low values of \({}^{\circ}\)_Brix_ were shown by SO4 in other studies performed in red cultivars, such as Cabernet Sauvignon [14] and Summer Black [18]. From our results, it can be observed a different tendency between vintages in terms of the rootstock influence on the sugar accumulation in the grapes. It is known that the total acidity and pH in response to rootstock vary depending on the scion [3]. The highest total acidity, in both years, was registered for grapes grafted on SO4 with values of 9.21 g/L for the 2009 vintage and 11.44 g/L for the 2010 vintage. Selection Oppenheim 4 (SO4) is one of the most used rootstocks, together with 110R. It displays strong vigor and plants grafted with this rootstock produces high yields [19]. Rootstocks that induced higher vigor to the scion have higher total acidity, and the reduction in grapes from less vigorous rootstocks is possibly a consequence of increased fruit exposure [3]. It is reported that _V. berlandieri_-derived rootstocks have lower potassium uptake, which contributes to a reduction in juice pH [20]. However, in our study, this behavior was not observed with the _V. berlandieri_-derived rootstocks (41B, 161-49C, 110R, SO4 and 420A). The lowest pH value in the 2009 vintage was registered for SO4 (pH of 3.35) and for 196-17C in the 2010 vintage (pH of 2.91). However, the highest pH values for the 2009 and 2010 vintages were registered for 41B and Gravesac (pH of 3.47) and Riparia G (pH of 3.16), respectively. Juice titratable acidity and pH were not affected by either rootstock or season in Cabernet Sauvignon [14]; however, the influence of rootstocks on titratable acidity and pH was described by other authors [8; 21; 22; 23; 24]. With respect to tartaric (TA) and malic (MA) acids, the same trend was observed for both vintages, with highest values for 420A in TA and SO4 in MA (Table 2). The difference between samples in concentrations of tartaric acid for year 2009 was of 0.5 g/L, and for malic acid, it was of 1.27 g/L. Meanwhile, this range in concentrations for 2010 was of 2.19 g/L and 1.5 g/L for TA and MA, respectively.