Effects of Diffuse Light Film Rain Shelter on the Growth and Fruit Quality of Fresh Grape

Scattered light can make the distribution of light in plant canopies more uniform. In this study, Vitis vinifera L. ‘Wuhe Cuibao’ fresh grapes was used as the test material, and open field cultivation was used as a control. The diurnal variation of light intensity under different materials of rain shelter film was studied to compare the effects of rain shelter film on photosynthetic characteristics, disease resistance, and fruit quality of grape leaves. The results showed that the light intensity under DL (diffuse light) film on the west side at noon was significantly higher than that under outdoor cultivation and EVA (ethylene vinyl acetate) film coverage. The daily average net photosynthetic rate of grape leaves covered with DL film on the east side is higher than that of open cultivation and EVA film covering. The incidence rate of leaf Downy mildew could be reduced by different materials of rain covering film, but the difference was not significant. Covering DL film can significantly increase the increase rate of soluble sugar and accelerate the decrease of titratable acid content in the west side. The content of VC (vitamin C)) in the eastern fruit under DL film was significantly higher than that of the control, and the total phenolic content in the fruit under DL film was significantly higher than that under EVA film. The DL film shelter can improve the light intensity, improve the photosynthetic capacity of grape leaves, and significantly improve fruit quality.