Evaluation of four new Rootstock genotypes obtained by back cross

The present research was started, in order to compare four new rootstocks, obtained by the Department of Crop Science (University of Milan) through a back cross breeding program, to 6 commercial ones (41B, 420A, 110R, 140Ru, 1103P and SO4). Four experimental vineyards respectively placed in the "Valpolicella", "Chianti Classico", "Castel del Monte" and "Contea di Sclafani" A.O.C. areas) were planted with these 10 rootstocks grafted to 'Cabernet Sauvignon' and a local cultivar. In those vineyards, 50 plants for each plot (combinations of rootstock-cultivar) were placed in randomized blocks, at about 5,000 vines/ha, and trained to a spur pruned cordon. From 2007 to 2009 and on a representative number of plants for each plot some measurements were made during vinification and winter pruning: agronomical parameters (Ravaz index, bud fertility, production weight/plant, bunches average weight, wood weight) and productive qualitative ones (pH, titratable acidity, soluble solids of musts, polyphenols and anthocyanins total contents of berry skins) were collected. Where it was possible, wines by a microvinification standard protocol were produced. Wines were chemically analyzed and sensory evaluations were carried out. Results showed that the new genotypes cause improved qualitative performances, they have different capabilities to modulate cultivars' vigor; they induce high accumulations of soluble sugars in musts; and good quantities of production/vine.