Effect of leaf removal on grapes of Cabernet Sauvignon and Sangiovese cultivated in different Italian environments

Leaf removal is a farming practice that can affect must and grape quality; it is closely related to the meteorological conditions of the year and the climate of the area. The present study aims to analyse the effects of different types of defoliation, all conducted at veraison and removing 5-6 basal leaves. The trial provided four tests: leaf removal only on the east side, only on the west side, total defoliation (both sides), and a non-defoliated treatment (control test). Two different cultivars, the Sangiovese and the Cabernet Sauvignon, were studied in five different Italian environments: Puegnago (BS), Scansano (GR), Bolgheri (LI), Brisighella (RA), and Montefalco (PG). The trial was repeated four times, once per year for the successive years 2007, 2008, 2009, and 2010. The years differed mainly with regard to the total rainfall; because of the variability of the years, different results, both for the same cultivar and between the cultivars, were observed. The differences existing between these two varieties and among the different environments led to different reactions to defoliation, especially concerning the analytical parameters of musts and grapes.