New training systems for high-density planting of sweet cherry

We assessed the vegetative growth and fruit production behavior of different sweet cherry cultivars grown using multiple new ultra-high-density planting (HDP) and training systems. An experimental orchard established in 2007 in the Ferrara province of Italy was used for this trial. The sweet cherry cultivars under evaluation were ‘Giorgia’ and ‘Grace Star®’ grafted on Gisela® 6; and ‘Black Star®’, ‘Early Bigi®’, ‘Early Star®’, ‘Ferrovia’, ‘Grace Star®’, ‘Kordia’, ‘Regina’, ‘Summit’, ‘Sweet Early®’, and ‘Sylvia’ grafted on Gisela® 5 rootstock. Each cultivar-rootstock combination was trained to spindle, V-system, or Super Spindle Axis (SSA). Planting densities ranged from 1905 trees/ha for spindle with Gisela® 6 to 5714 trees/ha for V-system and SSA with Gisela® 5. Vegetative growth, yield productivity, and fruit quality were evaluated. Among the three systems grafted on Gisela® 5, trees trained to the spindle system had the highest trunk cross-sectional area (26.2 cm2), followed by V-system (21.8 cm2) and SSA (20.2 cm2). Seven years after planting, ‘Ferrovia’ had the highest cumulative yield per hectare among cultivars on Gisela® 5, especially with V-system (50.5 t·ha-1) and SSA (52.2 t·ha-1) training systems. For cultivars on Gisela® 6, ‘Giorgia’ on had the highest cumulative yield per hectare after 7 years, but ‘Grace Star®’ on had higher production (≈14.0 t·ha-1with V-system and SSA and 12.8 t·ha-1with spindle) than ‘Giorgia’ in 2013.