The influence of rootstocks on the scions' aromatic profiles of Vitis vinifera L. cv. Chardonnay

In modern horticulture, grafting is widely used to confer biotic and abiotic stress tolerance, which can also affect many scion phenotypes, such as the physiochemical, phenolic and aroma compositions of grape berries. In this study, the effects of five rootstocks (101-14, 1103P, Beta, 5BB and SO4) on the berry ripening and aromatic profiles of Chardonnay (CH) grape berries over two years (2016 and 2017) were evaluated and some differences were observed. Compared to the own-rooted vines, berry weight was increased by the rootstocks to varying extents and the berries from all the five grafted vines accumulated significantly lower total soluble solids (TSS). CH/101-14 increased the berries' titratable acid (TA) to varying degree, showing decreased TSS/TA ratio in CH/101-14 and suggesting tendency for retarding maturation. All the rootstocks except SO4 could enhance both the total amounts of free- and bound-form volatile compounds, especially CH/1103P. Five volatile compounds, free-benzeneacetaldehyde, bound-1-octen-3-ol, bound-(E)-2-nonenal, bound-1,2,4-trimethyl-benzene and bound-1,2,3,4-tetramethyl-benzene were identified to have significant contribution to distinguish the grafted rootstock cultivar of the Chardonnay grape berries. Furthermore, characteristic volatile compounds for each rootstock were also screened out. Combined with the characteristics and concentrations of volatile compounds, rootstock 1103P could significantly improve the free and bound volatile compounds in Chardonnay berries under our experimental conditions.