Dr Petra King
Research Scientist - Viticulture
06 830 1230 Extension: 5230
My research has been selected after consultation with the local wine industry. Emphasis has been given to studying the role of vineyard variability on grape composition and wine quality for the Cabernet Sauvignon, Merlot and Syrah cultivars. Major conclusions from the research have important practical applications to the New Zealand wine industry.
Within vineyards, variability in vine growth is closely linked to soil variation, is widespread and is a particular issue on the premium production area of the Gimblett Gravel soils. This induces large differences in vigour which influence canopy size and light interception, fruit ripening, yield components, must composition, fermentation efficiency and wine composition and quality between zones within the block.
A consequence of the variability are widespread vine imbalances with crop load and vine growth unbalanced, resulting in inadequate or excessive vine vigour and/or abnormal fruit ripening patterns. Significant negative effects on wine sensory quality resulting from this variability were demonstrated, particularly excessive ‘greenness”.
The use of vineyard mapping techniques which derive indices of canopy variability, have been found to be good predictors of yield variability, grape quality and closely linked to the organoleptic properties of the resulting wines. Zonal management should be adopted to target areas where differential management such as irrigation or nutrition or harvest could be applied.
A priority of the research project has been to undertake a rigorous programme of extension and technology transfer with the industry. Presentations have also been made to international conferences through invited papers. Outcomes from the research have been written up as scientific papers for submission to scientific journals.
For example see:
King, P.D., McClellan, D.J., & Smart, R.E. (2012). Effect of severity of leaf and crop removal on grape and wine composition of Merlot vines in Hawke’s Bay vineyards. American Journal of Enology and Viticulture, 63(4), 500-507.