| Abstract:To find out the virus types of ‘Cabernet Gernischt’ at the eastern foot of Helan Mountain in Ningxia, and the effect of grape virus diseases on the fruit quality and the harvest time，we took the ‘Cabernet Gernischt’ as the test material, the types of virus in ‘Cabernet Gernischt’ grapes were identified by RT-PCR; Principal component analysis (PCA) was used to comprehensively evaluate the physical and chemical indexes of grapes for determining the best harvesting time of diseased and control grapes. The result showed that ‘Cabernet Gernischt’ were infected with GLRaV-1,GLRaV-2,GLRaV-3,GFLV,GRSPaV,GVA,GPGV and GINV, and the phenomenon of compound infection was serious. Compared with the control group, the SPAD value decreased by 14.89%, the net photosynthetic rate decreased by 17.21%, the leaf stomatal conductance decreased by 37.77%, the soluble solids decreased by 19.36%, the reducing sugar decreased by 18.09%, the sugar acid ratio decreased by 25.24% and the titration acid content increased by 15.94%. According to PCA, the best harvesting time of control group in 2020 in the region was September 20, and the best harvesting time of infected grape was September 27. In summary, ‘Cabernet Gernischt’ can be infected with 8 kinds of grape viruses, the photosynthesis of diseased grapes decreases， and the accumulation of soluble solids, reducing sugars, tannins declines.Thus the harvesting period of wine grapes is postponed for a week. |
