Tools for terroir classification for the grape variety Kékfrankos

A 3-year study was carried out in order to evaluate the ecophysiology, yield and quality characteristics of Vitis vinifera L. cv. Kékfrankos (syn. Limberger) at Eger-Nagyeged hill (steep slope) and at Eger-Kőlyuktető (flat) vineyard sites located in the Eger wine region, Hungary. The aim of this paper was to analyse the effect of ‘vintage’ and ‘terroir’ on the seasonal changes of Kékfrankos ecophysiology and its possible relationship with yield and wine composition. Grapevine physiological responses (midday- and pre-dawn water potential, pressure–volume analysis and gas-exchange), yield and wine composition of each vineyard were studied. Lower grapevine water supply was detected at Eger-Nagyeged hill in each season due to its steep slope and soil characteristics. Stomatal conductance, transpiration rate and photosynthetic production per unit leaf area were affected by water availability. Lower yield in Eger-Nagyeged hill was partly associated with decreased photosynthetic production of the canopy. Improved wine quality of Eger-Nagyeged hill was due to moderate water stress which induced higher concentration of anthocyanins and phenolics in the berries. There was a close relationship between environmental conditions, Kékfrankos gas exchange, water relations, yield and wine composition. Water deficit plays an important role in creating a terroir effect, resulting in decreased yield, better sun exposure of leaves and clusters and thus higher concentration of phenolics and anthocyanins. Although quality is mainly influenced by vintage differences, vineyard characteristics are able to buffer unfavourable vintage effects even within a small wine region. Stomatal conductance, pre-dawn water potential and climatic data may be reliable parameters for terroir classification, although variety–terroir interactions must always be considered.
Data of Geographycal Information System (GIS) performed in this study may serve as part of the data base, that we are engaged in the Eger wine district in Hungary.