Effects on fruit production and quality of different dormant pruning intensities in 'Bing'/'Gisela®6' sweet cherries (Prunus avium) in Central Chile

Fruit size is a very important quality attribute in cherry trees. Appropriate canopy and crop load management are, therefore, required to obtain an adequate balance between the yield and fruit size. A study was carried out during the 2007-2008 season in the Maule Region of Chile to evaluate the effect of increasing levels of dormant pruning (Control, no removal; Soft pruning, 15% removal; Moderate pruning, 30% removal and Intense pruning, removal of 50% of the fruiting wood) on the fruit yield, quality (size, fruit weight, soluble solids and fruit firmness) and crop value of sweet cherries (Prunus avium L.) cv. 'Bing' on the dwarfing rootstock, 'Gisela 6'. Treatments at the 30 and 50% removal intensities had a strong effect on yield reduction (36.1% and 67% decreases, respectively). The fruit size distribution, firmness and soluble solids were positively affected by the removal treatments. The amount of fruit with no fresh market quality (< 22 mm) was reduced by the pruning (15% of the fruit of the control represented this category). Treatment at the 15% removal intensity had a strong effect in reducing the amount of small fruit to very low levels (2% of the total fruit) and promoting the yield of premium fruit (diameter > 28 mm) (52% of the total fruit) without affecting the total yield (kg fruit per tree). The crop value was improved in the cases of soft (212.7%) and moderate (140.4%) dormant pruning. Soft dormant pruning emerges as a practical approach for improving the yield, quality, fruit size distribution and crop value in this rootstock-variety combination, but long-term studies should be carried out to assess any carryover effects on the yield and, especially, the crop load balance.