Effect of Rootstocks on the Volatiles in Grape Berries of Vitis vinifera L. cv. ‘Petit Verdot’

In this study, the wine grape cultivar Vitis vinifera L. cv. ‘Petit Verdot’ was used as the scion for ‘101-14’, ‘5BB’, ‘SO4’, ‘Beta’ and ‘1103P’ rootstocks as well as self-rooted control. The volatile components of ‘Petit Verdot’ grape berries from the commercial harvest period in 2016-2017 were analyzed by using head space solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results showed that the climate differences between vintages were the decisive factor affecting the contents of volatile components in ‘Petit Verdot’ grapes, which were also significantly affected by rootstocks. Compared with the self-rooted control, all five rootstocks significantly increased the contents of C₆/C₉ compounds in grapes. ‘5BB’ significantly increased the contents of C₁₃-norisoprenoids and terpenes, ‘1103P’ significantly increased the content of bound carbonyl compounds, ‘101-14’ significantly increased the content of free carbonyl compounds and significantly decreased the content of bound C₁₃-norisoprenoids, ‘Beta’ significantly increased the contents of bound C₁₃-norisoprenoids and terpenes, and ‘SO4’ significantly increased the contents of C₁₃-norisoprenoids, bound carbonyl compounds and free terpenes. Orthogonal partial least squares-discriminant analysis (OPLS-DA) results showed that C₆/C₉ compounds, such as (E)-2-hexenal, (Z)-2-hexenal and hexanal, were the common differential volatile components to differentiate the grafted grapes from the self-rooted ones. In general, grafting ‘Petit Verdot’ onto the rootstock ‘5BB’ in Beijing was conducive to the accumulation of terpenes and C₁₃-norisoprenoids in grapes during harvest.