Influence of elevation and slope exposure upon productivity and must quality of "Touriga Nacional" (Sub-region of Douro Superior)
Abstract
Aims: This work presents the results of a 3 year study on the influence of elevation and slope exposure upon the productivity and quality of the Touriga Nacional variety.
Methods and results: Touriga Nacional variety standing on 18 plots dispersed along the sub-region of Douro Superior (laid out in a randomized complete block design). We determinate productivity, alcohol, volume, mass, total acidity, chromatic characteristics, anthocyanins, polyphenol index, maturation index, vegetative mass, vigour estimation and ravaz index.
Conclusion: The results revealed a decrease in most parameters related to productivity and quality as the elevation increases and, simultaneously, the concentration of phenolic compounds increased proportionally in relation to elevation. In relation to the plots set either on northern or southern exposures, the SW and NW exposures surpass the N, S, NE, and SE exposures in terms of the concentrations phenolic compounds, but all other parameters, either productivity or quality related, had lower values.
Significance and impact of study: The results confirm the importance of elevation and slope exposure of sub-region Douro Superior, in productivity and must quality of Touriga Nacional.