Estimation of grape quality in vineyards using a new viticultural index

Crop yield, total leaf area, canopy surface area and other vineyard parameters were determined on different 'Tempranillo' and 'Grenache' (Vitis vinifera L.) vineyards situated in Rioja appellation (Spain). All parameters were determined during three years. Grape vineyard assessment was performed by Vitur scoresheet, proposed by TARDAGUILA and MARTINEZ DE TODA (2005). The main chemical composition parameters of grape pulp and skin were also determined. The correlations between the viticultural variables and the chemical composition variables of the grapes were also analysed. The parameter that displayed the best correlation with grape phenolic composition was the CSA/Y/ShL parameter, referred to as the Toda Index. This index could be used to estimate the phenolic composition of grapes. It also presented the best correlations with grape quality, estimated using the Vitur score-sheet. These results suggest that, for winegrape vineyard assessment, Vitur score-sheet (necessarily subjective) may be replaced with the new Toda index (faster and objective). The main advantage of this new parameter is that it is easy to determine and is completely objective, unlike visual estimation which offers a high degree of subjectivity.