The anthocyanin composition, fatty acids, and volatile aromas are important for Cabernet Sauvignon grape quality. This study evaluated the effect of exogenous abscisic acid (ABA) and methyl jasmonate (MeJA) on the anthocyanin composition, fatty acids, lipoxygenase activity, and the volatile compounds of Cabernet Sauvignon grape berries. Exogenous ABA and MeJA improved the content of total anthocyanins (TAC) and individual anthocyanins. Lipoxygenase (LOX) activity also increased after treatment. Furthermore, 16 fatty acids were detected. The linoleic acid concentration gradually increased with ABA concentration. The fatty acid content decreased with increasing MeJA concentration and then increased again, with the exception of linoleic acid. After exogenous ABA and MeJA treatment, the C6 aroma content increased significantly. Interestingly, the exogenous ABA and MeJA treatments improved mainly the content of 1-hexanol, hexanal, and 2-heptanol. These results provide insight into the effect of plant hormones on wine grapes, which is useful for grape quality improvement.

Rain-shelter cultivation is an effective cultural method to prevent rainfall damage during grape harvest and widely applied in the Chinese rainy regions. In this study we investigated the effect of rain-shelter cultivation on grape diseases and phenolic composition in the skins of Vitis vinifera cv. Cabernet Gernischet grape berries through the comparison with open-field cultivation at two vintages (2010 and 2011). The results showed that rain-shelter cultivation reduced the incidence of grape diseases significantly and delayed the maturation of Cabernet Gernischet fruits. With regards to most of the phenolic compounds identified in this study, their content in grape samples under rain-shelter cultivation was decreased compared to those under open-field cultivation. However, rain-shelter cultivation stimulated the accumulation of dihydroquercetin-3-O-rhamnoside in grape skins during grape maturation. These were related with micrometeorological alterations in vineyards by using plastic covering under rain-shelter cultivation. It suggests the rain-shelter cultivation makes possible the cultivation of “Cabernet Gernischet” grapes in an organic production system, for providing a decrease in the incidence of diseases and the dependence on chemical pesticides in the grape and wine industry.

Covering vineyards with rain-shelters is an effective viticulture practice to protect grapes from adverse environments, and the rain-shelter can influence radiometric properties, canopy microclimate, and grape berry quality. We investigated the effect of rain-shelter cultivation covered with different coloured plastic films on canopy microclimate and anthocyanins in the skins of Cabernet Sauvignon grape berries through comparison with open-field cultivation (control) of two vintages (2013 and 2014) in northern China. The results show that the highest average temperature and lowest relative humidity were presented by the grape canopies in the open-field cultivation, followed by the colourless, blue, purple, yellow, and red film. Higher infrared radiation was recorded in control plants. The content of sugar in the berries under rain-shelter cultivation (except colourless film in 2013) was significantly higher than that of the control. The concentrations of most anthocyanins were significantly decreased under the yellow and colourless films in the two vintages. The red and purple films increased the concentration of 3ʹ,5ʹ-substituted, methoxylated, and acylated anthocyanins in the grapes in both vintages. The results suggest that the application of such films may be useful for the production of high-quality wine grapes in warm temperate climates with dry winter and hot summer regions.