To improve grape photosynthesis, yield and fruit quality by covering reflective film on the ground of a protected facility

Grapes are often cultivated in protected facilities used as rain-shelter and insect-proof in Southern China, which results in a decrease in light intensity reaching the canopy of grapevines. To optimize the light environment, reflected light techniques are being used to cover the vineyard ground. The present study aimed to assess the practicability of reflective film covering on the ground of a protected facility to improve grape photosynthesis, yield and fruit quality. 'Shine muscat' grapes grafting with '5BB' and '3309m' rootstocks were grown in a protected facility covered with film on the roof as a rain-shelter and fine-mesh screens on the side as an insect-proof, in which covering reflective film on the ground were arranged as treatments. The experimental results show that the growth indexes of grapevines were higher than control, but there was no significant difference. Covering reflective film on the ground can improve the net leaf photosynthetic rate (Pn) by 24.9% and 35.2% for 'Shine muscat' grafting with 3309m rootstocks and 5BB rootstocks, respectively. The grape yield of 'Shine muscat' grafting with 3309m rootstock was increased by 46%, while increased by 2.7% for 3309m rootstock. The sugar:acid ratio and aroma composition were improved with the application of reflective film covering on the ground. Our results revealed that covering reflective film on the ground of a protected facility can improve grape photosynthesis, yield and fruit quality.