Targeted manipulation of vine balance: Does vine balance directly affect fruit composition?

E. J. Edwards, Jason Smith, A Walker, Celia Barril, A. Boettcher, David Foster, Julia Gouot, Peter Clingeleffer, Bruno Holzapfel

Research output: Book chapter/Published conference paperConference paper


Vine balance is a concept describing the relationship between carbon assimilation (usually estimated using a measure of canopy size, such as pruning weight) and utilisation of the resulting carbohydrates for fruit production (usually estimated using harvest yield). Manipulating vine balance through leaf area or crop load adjustments affects the proportion of the vine’s carbohydrate production required to mature the fruit. It is commonly considered that composition of the berry, and resulting wine, is strongly affected by vine balance. Field manipulations of vine balance were replicated in three contrasting regions, Hilltops, Murray Darling and Langhorne Creek, for three seasons. These were early defoliation (pre-capfall), late defoliation (pre-veraison), 50% crop removal (pre-veraison) and minimal pruning. Defoliation was also simulated in mature, fruiting, potted vines at Wagga Wagga, by enclosing whole vines in chambers and supplying them with low CO 2 air. This allowed the impact of defoliation on vine carbon assimilation to be separated from any impact on bunch exposure. Changing vine balance affected the fruit maturation rate, but had a less consistent effect on fruit composition. Late defoliation (higher ratio of fruit load to canopy size) reduced total anthocyanin content, despite elongating the maturation period, whereas crop removal had little effect. Interestingly, early defoliation had a limited effect on vine balance, but resulted in increased total tannin content. In both cases, it is possible that the observed compositional effects were caused by changes in bunch environment. Reducing carbon assimilation in the chamber experiment also reduced maturation rate, but did not affect the relationship between sugar and anthocyanin concentrations in the berry. Overall, there was no conclusive evidence that the changes in vine balance achieved had a direct effect on fruit composition.
Original languageEnglish
Title of host publicationProceedings of the 16th Australian Wine Industry Technical Conference
EditorsK. S Beames, E.M.C Robinson, P.R. Dry, D.L. Johnson
Place of PublicationGlen Osmond, SA
PublisherAustralian Wine Industry Technical Conference Inc.
Number of pages5
ISBN (Print)9780987048097
Publication statusPublished - 2016
Event16th Australian Wine Industry Technical Conference (AWITC 2016) - Adelaide Convention Centre, Adelaide, Australia
Duration: 24 Jul 201628 Jul 2016 (Website) (Proceedings)


Conference16th Australian Wine Industry Technical Conference (AWITC 2016)
OtherThe 16th Australian Wine Industry Technical Conference and Trade Exhibition was conducted from 24-28 July 2016 at the Adelaide Convention Centre. Attendee numbers were the highest (>1,100) since the 2007 Conference in Adelaide, with the overwhelmingly positive feedback received to date indicating that all found the event to be a great success.
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