High density planting for sweet cherry orchards

While a number of training systems are suitable for increasing sweet cherry planting density, the V and vertical axis systems are perhaps best suited to the task. New ideas regarding tree shape include short trees grown using dwarfing rootstocks like the Gisela® series. Research now needs to discover ways to improve tree efficiency under dwarfing or semi-dwarfing rootstocks. We report two ongoing cherry training system trials. The first trial, now in year 3, compares the vertical axis, spindle and V training systems, the dwarfing rootstocks Gisela® 5 and Gisela® 6 in planting densities of 1,905 and 5,714 trees ha-1, and the cultivars (11) Early Bigi, Sweet Early, Early Star, Giorgia, Grace Star, Black Star, Summit, Sylvia, Ferrovia, Kordia and Regina. The second trial involves trees trained to vertical axis with ‘Kordia’ and ‘Ferrovia’ at ultra-high densities of 5,000 (4.0 x 0.5 m) and 6,666 (3.0 x 0.5 m) trees ha-1 in two orchards, both at year 6. Cumulative yield of ‘Ferrovia’ in the second trial at year 6 was 46.6 t ha-1. Cherry quality was very high: 88.8% of the fruit at the density of 5,000 trees ha-1 and 89.8% at 6,666 trees ha-1 were over 28 mm in diameter.