Berry anthocyanin content of Cabernet Sauvignon (Vitis vinifera L.) cultivated under rain-shelter systems with different coloured plastic films

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 3',5'-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.