Effetto della vigoria della pianta e dell’esposizione del vigneto sui metaboliti secondari della cv Nebbiolo

The effect of vine vigour and vineyard exposure on secondary metabolite accumulation in the berries of the cv Nebbiolo was investigated. The data were collected in two commercial vineyards, located in Sinio (North-West Italy), characterized by high vigour heterogeneity, and by a South and Western slope exposure. Vineyard parcels were sorted in three vine vigour classes (V-, V+ to South and V++ to Western). From 15 days after flowering until harvest, berry samplings were collected and the amount of carotenoids and C13 nor-isoprenoid compounds were measured. Similar seasonal trend for B-carotene concentrations in all vigour conditions was observed. The high vigour of V++ vines delayed the accumulation of lutein during the first part of the berry development and until véraison, while significant differences between the parcels were found at harvest time. Actually, grapes less protected from direct radiation had the lowest lutein concentrations. Both synthesis and degradation of carotenoids may depend on vineyard exposure and cluster microclimate modifications, but a variety effect is also probable. Total norisoprenoids accumulated during season without great differences between V- and V + plots, but in the V++ plot norisoprenoid accumulation was delayed. At harvest time, total nor-isoprenoids concentration was significantly lower in the warmest plot (V–) whereas, for the two vigorous plots (V+, V++), it resulted quite similar even if the seasonal pattern accumulation showed differences. In addition to the vigour, the vineyard exposure played a probable role on norisoprenoids seasonal trend.