Within-vineyard variation in the ‘pepper’ compound rotundone is spatially structured and related to variation in the land underlying the vineyard

Authors

  • N.J. Scarlett,

    1. C/- Rathbone Wine Group, Port Melbourne, Vic., Australia
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    • Nathan James Scarlett died on 11 July 2013 after a struggle with cancer that lasted several years; he was 37 years old. In spite of the considerable difficulties his illness placed on him, he was the initiator of, and driving inspiration behind the work described here and remained determinedly and actively involved in it right up to the time of his passing. Nathan was the National Technical Viticulturist with the Rathbone Wine Group, husband to Jacqueline and father to Charlie and Heidi. He will be sorely missed.
  • R.G.V. Bramley,

    Corresponding author
    1. CSIRO Ecosystem Sciences, Waite Campus, Glen Osmond, SA, Australia
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  • T.E. Siebert

    1. The Australian Wine Research Institute, Glen Osmond, SA, Australia
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Abstract

Background and Aims

Previous studies have highlighted the importance of vineyard variability and the benefits that may accrue through targeting management in response to it. In this study, we were interested to see whether the concentration of rotundone in Shiraz (Vitis vinifera L.) grapes was spatially structured and related to other aspects of vineyard variability so as to inform the possible selective harvesting of grapes destined for wines of ‘peppery’ character.

Methods and Results

Immediately prior to harvest of a 6.1-ha block in the Grampians region of Victoria, a region known for producing wines of ‘peppery’ character, fruit was sampled from 177 ‘target vines’ and analysed for its rotundone concentration. The resulting data were mapped and overlain with other map layers describing variation in soils, topography and vine vigour. Berry rotundone concentration was found to be markedly spatially variable. The results further suggest that within-vineyard variation in berry rotundone concentration is associated with variation in soil properties and topography, with the influence of the latter on ambient temperature implicated as a likely key driver of rotundone variation.

Conclusions

Consistent with previous analyses of variability in indices of fruit quality, variation in berry rotundone concentration was found to be spatially structured; that is, its variation was not random. As with these previous studies, variation in berry rotundone concentration was associated with variation in the land underlying the vineyard.

Significance of the Study

To our knowledge, this is the first study of within-vineyard spatial variability in a grape-derived flavour compound. It highlights the potential opportunity, with further understanding of rotundone biosynthesis, to use selective harvesting and/or viticultural manipulation as a means of influencing wine style – in this case the ‘pepperiness’ of Shiraz.

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