Differential Analysis of Fruit Quality of ‘Cabernet Sauvignon’ Grapevines with Different Shoot Densities

The basic physicochemical indicators, phenolic composition and aroma composition of fruits from five-yearold ‘Cabernet Sauvignon’ grapevines with four shoot densities of 15, 20, 25, and 30/m from the wine production area of the Qingtong Gorge at the eastern foothill of Helan Mountain in Ningxia were analyzed, and principal component analysis (PCA) was used to investigate monomeric anthocyanin contents and comprehensive fruit quality. The results showed that there were differences in the physical indicators of grape bunches and individual grapes and the chemical indicators such as sugar, acid, phenolics, and aroma substances among different shoot densities (P < 0.05). The contents of total monomeric anthocyanins and total aroma compounds were negatively correlated with shoot density, and the basic physicochemical indicators, phenolic composition and overall aroma quality of grapes with lower shoot density (15–20 m) were better. The PCA performed on monomeric anthocyanin contents showed a clear distinguishment between the different treatments, and the shoot density of 15/m had more obvious effect on monomeric anthocyanin contents. The decreasing order of the comprehensive fruit scores was 15 > 20 > 30 > 25/m. In conclusion, for ‘Cabernet Sauvignon’ grapes in the wine production area of the Qingtong Gorge, the comprehensive fruit quality was best at a shoot density of 15–20/m.