Il cordone speronato sul vitigno Barbera.

The traditional pruning system in Piedmont (North-West Italy) is the Guyot system; it requires trained personnel, difficult to find, and it does not permit the mechanization of winter pruning, thus it is very expensive. An alternative technique that could allow the reduction of the vineyard management costs could be the spur-pruning which is simpler to perform and fully mechanized. It is used in many grape-growing countries with satisfactory results, but it is not always positively valued in Piedmont. In order to estimate its agronomical and oenological validity in this environment, multi-year observations of the vegetative behaviour, yield and quality of ‘Barbera’ grapes and wines produced by micro-vinification, have been carried out. The spur pruning induced delay of bud burst, a greater vegetative activity, increasing development of latent and secondary buds, but lead to a lower productivity than cane-pruning system. This induced an addition of labour for early manual operations (+ 15 %) and a reduction of labour for the expensive cluster thinning (- 10 %). Furthermore, the winter pruning of cordon may be fully or partially mechanized with a significant cost reduction of vineyard management. The crop parameters were not affected by the type of pruning except for the berry weight that was higher in spur pruned vines even if less influenced by vintage and thinning. The quality of the grapes from spur pruned vines was often better, or at least perfectly comparable, to that of cane-pruned ones and the relative wines are often been favoured by the tasting panel. In the light of these results, nothing precludes the use of spurpruning for the ‘Barbera’ vines; opting for this system it would be necessary to correctly evaluate the number of buds per plant and the most appropriate planting distances in relation to the environment features, to avoid difficulties in balancing canopy development and crop load with manual interventions.