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IVES 9 IVES Conference Series 9 Application of the simplified quality bioclimatical index of Fregoni: suggestion of using its evolution curve

Application of the simplified quality bioclimatical index of Fregoni: suggestion of using its evolution curve


Les indices bioclimatiques constituent un bon outil pour piloter le développement vitivinicole dans une région précise. Plusieurs indices bioclimatiques ont été proposés par la littérature mondiale (WINKLER 1970; HIDALGO, 1980; HUGLIN, 1986, TONIETO et CARBONEAU, 2000), mais pour des raisons physiologiques ces indices n’incluent pas dans leurs formules les températures journalières inférieures à 10 °C, à l’exception de l’indice de FREGONI (FREGONI et PEZZUTTO, 2000). Cet auteur établit une relation entre les variations thermiques, les températures inférieures à 10 °C et la qualité des vins, en particulier pour les 30 jours précédant les vendanges. Parmi les indices appliqués au Chili, celui de WINKLER et AMERINE (WINKLER, 1970) est probablement le plus utilisé, cependant il présente quelques liplites (Mc INTYRE et al. 1987; JACKSON et CHERRY, 1988) et des résultats incongrus ont été signalés pour le Chili. En effet, il classe dans le même groupe des zones littorales avec d’autres proches à la cordillère des Andes, présentant des températures moyennes similaires mais avec des variations thermiques sensiblement différentes (SANTIBANEZ et al. (1984).
FREGONI et PEZZUTTO (2000) affirment que le Chili présente les plus hautes variations thermiques journalières pendant le mois précédant la récolte, ce qui justifierait l’utilisation de l’indice de FREGONI pour la vitiviniculture de ce pays.
On a utilisé la formule simplifiée de l’indice de FREGONI (IFss), en multipliant l’amplitude thermique par le nombre de jours au-dessous de 10 °C pour le mois précédant la récolte, sans, prendre en compte le nombre d’heures pendant lesquelles ces températures au-dessous de 10 °C se maintiennent : IFss = Σ (T maxima – T minima)*Σ (N° jours < 10° C). L’indice de FREGONI est calculé pour le mois précédant la récolte, en l’occurrence, le mois de mars pour l’hémisphère sud.
Le calcul de l’indice de FREGONI pour différents lieux de la région du Maule au Chili permet de différencier 4 zones agroclimatiques. Ces valeurs obtenues ne correspondent pas .aux niveaux les plus élevés possibles pour ces zones, qui se produisent généralement pendant le mois d’avril.
Par ailleurs, au Chili et plus particulièrement dans les zones de la région du Maule, les vendanges s’étalent, en fonction du cépage, du mois de février à mai. Par conséquent, le calcul de l’indice uniquement pour le mois de mars se révèle inapproprié.
Afin de mieux caractériser chaque lieu, on propose donc l’utilisation de la courbe d’évolution de IFss, caractérisée par 4 périodes. Cette courbe d’évolution de l’indice peut avoir différentes applications pratiques.

Bioclimatic indices are good tools to orientate the development of viticultural areas. Several bioclimatic indices have been proposed in international literature (WINKLER 1970; HIDALGO, 1980; HUGLIN, 1986, TONIETO et CARBONEAU, 2000) but, for physiological reasons, daily temperatures under 10°C are not included, excepted in FREGONl’s index (FREGONI and PEZZUTTO, 2000). These authors establishes a relationship between daily temperature variations, temperatures under 10°C and wine quality, for the 30 days before harvest.
WINKLER and AMERINE’s index (WINKLER, 1970) is certainly the most frequently used, among different climatic indices used in Chile. However, it has some limitations (Mc INTYRE et al. 1987; JACKSON and CHERRY, 1988) and some wrong results have been reported for Chile. In fact, this index classifies in the same class coastal zones and closed to the Andes mountains areas. For these two areas, average temperatures are similar but daily variations oftemperature are quite different (SANTIBANEZ et al. 1984).
FREGONI and PEZZUTTO (2000) observed that Chile presents the highest daily variations of temperature during the month before harvest and suggested that it could justify the use of FREGONI’ s index for Chilean viticultural areas.
Simplified FREGONI’ s indice (lfss) was used by multiplying daily temperature amplitude and the number of days under 10°C, for the month before harvest, but not regarding duration of temperature under 10°C period: Ifss = S (T maxima – T minima)*S (N° days < 10° C). FREGONI’ s index is calculated for the month before harvest, March for the southern hemisphere.
FREGONI’ s index was applied to different areas of Chilean Maule region and 4 agroclimatic zones were distinguished. Results don’t correspond to the highest potential levels for these areas, generally found in April. In Chile, and more particularly in the Maule region, the harvest period spread from February to May, according to the cultivar. Consequently, FREGONl’s index application only for March is quite inexact. The lfss curve evolution, characterized by 4 periods, is proposed to characterize viticultural areas. This curve presents different practical applications.





Publication date: February 15, 2022

Issue:Terroir 2002

Type: Article



(1) Departamento de Fruticultura y Enología
Facultad de Agronomia e Ingenieria Forestal
Pontificia Universidad Catolica de Chile
Casilla 306-22, Santiago, Chile
Manuel Montt 1164; Santiago, Chile

Contact the author


Chili, zonage vitivinicole, indice bioclimatique
Chile, viti-vinicultural zoning, bio-climatic index


IVES Conference Series | Terroir 2002


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