Condizioni microclimatiche e profilo antocianico della cultivar ‘Nebbiolo’.

Leaf shading delays the anthocyanin accumulation, but has no significant effect on final anthocyanin content. It is generally accepted that cluster shading reduces anthocyanin accumulation. Furthermore, excessively high temperatures can reduce anthocyanin accumulation. The aim of this study was to evaluate the effects of modifications of the bunch-zone microclimate on Nebbiolo grape anthocyanin composition. During 2006 and 2007, five exposure levels were assigned to fruit-zone by means of leaf removal or the application of shading nets: vines exposed to a natural shading throughout the experimental season (control, T), fruit-zone shaded vines from fruit-set to veraison (AI), fruit-zone shaded vines from fruit-set to harvest (AR), fruit-zone shaded vines from veraison to harvest (IR) and fruit-zone leaf-removed vines at fruit-set (SF). Leaf removal did not alter either the total anthocyanin content or the anthocyanin profile. Fruit-zone artificial shading reduced total anthocyanin and di-substituted anthocyanin contents and increased tri-substituted anthocyanin content in comparison with control vines. It seems that natural shading gave the best results as to the parameters studied in this experiment. Results confirm that temperature, together with solar radiation, can influence the anthocyanin total amount and profile.