The aim of this work by Ross Sanders, of the Australian Research Council Training Centre for Innovative Wine Production (ARC TC-IWP), The University of Adelaide, and Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture and Food, was to investigate the impact of spatial variation in vine vigour on the accumulation of methoxypyrazines in the rachis of Cabernet Sauvignon.
Cabernet Sauvignon rachis has been shown to contain significantly higher concentrations of 3-isobutyl-2-methoxypyrazine (IBMP) than that found in berry material. IBMP is readily extracted from rachis during fermentation and can impact the flavour profile of the produced wine.
In this study, Cabernet Sauvignon vines (n = 105) grown on common rootstocks in Coonawarra, South Australia, were georeferenced and 6 bunches were harvested from each vine at maturity in 2020. Berries were removed and the rachis was analysed for IBMP by GC-MS/MS. Pruning weights were recorded as an indicative measure of vegetative growth over the past season. Visualisation and analysis of map layers was achieved through linear regression models and k-means clustering with the Precision Agriculture Tools plugin for QGIS software suite.
Did the georeferenced maps of vine vigour and IBMP concentration in rachis show similar spatial variance? Was a clear relationship between the two variables evident across the vineyard? Find out how the k-Means clustering revealed 3 distinct zones, whether rootstocks or the inherent vineyard variability influenced vine vigour, and if vine vigour significantly correlatse with IBMP in Cabernet Sauvignon rachis.
Video of the seminar held during Macrowine virtual (June 23-30, 2021)
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