Context and purpose of the study ‐ Temperatures are increasing due to climate change leading to advances in grapevine phenology and sugar accumulation in grape berries. This study aims (i) to develop a temperature‐based model that can predict a range of target sugar concentrations for various cultivars of Vitis vinifera L and (ii) develop extensive classifications for the sugar ripeness of cultivars using the model.
Material and methods ‐ Time series of sugar concentrations were collected from research institutes, extension services and private companies from various European countries. The Day of the Year (DOY) to reach the specified target sugar concentration (170, 180, 190, 200, 210, and 220 g/l) was determined and a range of models tested using these DOYs to develop the best fit model for Vitis vinifera L.
Results ‐ The best fit linear model– Growing Degree Days (parameters: base temperature (t0) = 0°C, start date (Tb) = 91 or 1 April), Northern Hemisphere) – represented the model that required the least parameters and therefore the simplest in application. The model was used to characterise and classify a wide range of cultivars for DOY to reach target sugar concentrations.
The model is referred to as the Grapevine Sugar Ripeness Model (GSR). It is viticulturist‐ friendly as it’s simple in form (linear) and its growing degree day units are easily calculated by adding average temperatures (base temperature was optimized at 0°C) derived from weather stations from the 91th day of the year (Northern Hemisphere). The classifications based on this model can inform cultivar choice as an alternative adaptation strategy to climate change, where changing cultivars may prevent the harvesting of grapes at high sugar concentrations which leads to higher alcohol wines.
Authors: Amber K. PARKER (1), Inaki GARCÍA DE CORTÁZAR‐ATAURI (2), Laurence GÉNY (3), Jean‐Laurent SPRING (4), Agnès DESTRAC (5), Hans SCHULTZ (6), Manfred STOLL (6), Daniel MOLITOR (7), Thierry LACOMBE (8), Antonio GRACA (9), Christine MONAMY (10), Paolo STORCHI (11), Mike TROUGHT (12), Rainer HOFMANN (1), Cornelis VAN LEEUWEN (5)
(1) Department of Wine, Food and Molecular Biosciences, Faculty of Agriculture and Life Sciences, PO Box 85084, Lincoln University, Lincoln 7647, Christchurch, New Zealand
(2) Institut National de la Recherche Agronomique (INRA), US 1116 AGROCLIM, F-84914 Avignon, France
(3) Institut des Sciences de la Vigne et du Vin, Université de Bordeaux, Unité de Recherche Oenologie EA 4577 – USC 1366 INRA, 210 chemin de Leysotte – CS 50008, 33882 Villenave d’Ornon cedex
(4) Agroscope, Av. de Rochettaz 21,1009 Pully, Switzerland
(5) EGFV, Bordeaux Sciences Agro, INRA, Univ. Bordeaux, ISVV, 33883 Villenave d’Ornon, France
(6) Hochschule, Giesenheim University, Von-Lade-Straße 1, D-65366 Geisenheim
(7) Luxembourg Institute of Science and Technology (LIST), Environmental Research and Innovation (ERIN) Department 41, rue du Brill, L-4422 Belva, Luxembourg
(8) Institut National de la Recherche Agronomique (INRA), AGAP, Univ Montpellier, CIRAD, INRA, Montpellier SupAgro, 2 place Viala, F-34060 Montpellier, France
(9) Sogrape Vinhos S.A., R. 5 de Outubro 558, 4430-809 Avintes, Portugal
(10) Bureau Interprofessionnel des Vins de Bourgogne – BIVB, 12 boulevard Bretonnière, 21200, Beaune, France
(11) CREA – Centro di ricerca Viticoltura ed Enologia, Viale Santa Margherita 80 52100 – Arezzo, Italy 12The New Zealand Institute for Plant and Food Research Limited, Blenheim 7240, New Zealand, Department of Wine, Food and Molecular Biosciences, Faculty of Agriculture and Life Sciences, PO Box 85084, Lincoln University, Lincoln 7647, Christchurch, New Zealand
Keywords: modelling, temperature, sugar, cultivars, climate change