Long-term performance of Barbera grown under different training systems and within-row vine spacings.

The effects of training systems established as vertically shoot-positioned spur-pruned low cordon (SPC), single high-wire cordon (HW), single Guyot (SG), and vertically split double Guyot (DG) were tested over five years (2003–2007) on Vitis vinifera L. cv. Barbera vines planted at 2.5 m interrow and at 0.9 m, 1.2 m, and 1.5 m within-row spacings. In the spur-pruned (SPC and HW) systems, total shoots per count node were about three-fold the values recorded in SG and DG, while vine capacity as total leaf area throughout the trial was highest in SPC (6.48 m2) and lowest in SG (2.93 m2), although the latter bore the most vigorous shoots. Vine capacity measured as leaf area decreased linearly with increasing within-row spacing. Yield per meter of row decreased by ~20% at 1.5 m as compared to 0.9 m vine spacing. No significant differences were found in the yield per vine across training systems, as higher shoot number in SPC and HW was offset by higher shoot fertility and cluster weight in the cane-pruned systems. Must composition at harvest was similar among SPC, HW, and SG, while DG produced grapes of overall inferior quality. Vine spacing had no effects on grape composition. Results indicate that in Barbera similar crop potential and quality expression can be achieved in either cane- or spur-pruned training systems when properly managed. Vine spacing at 0.9 m within-row is advisable as it ensures 20% higher yield per hectare at very similar grape quality across training systems.