Renewal of fruiting wood to maintain young reproductive meristems with optimal canopy light interception and distribution is key for high productivity and fruit quality throughout the life of a sweet cherry (Prunus avium L.) orchard. Typical renewal involves replacement of 10 to 20% of the tree canopy annually by removing one to several of the largest branches. In a mature orchard, this renewal process is subject to competition between sun-exposed fruiting sites and interior canopy renewal sites that intercept less light and compete poorly for translocated photoassimilates, often resulting in poor renewal growth. This is particularly problematic for high density orchards that utilize rootstocks selected for reduced vigor and high productivity. Renewal of canopy fruiting sites on a whole tree basis is an alternative renewal method that eliminates the competitive inhibition of shoot regrowth. This study explores the initial response of sweet cherry trees on various training systems and size-controlling rootstocks to whole tree renewal. Four training systems were studied: Tall Spindle Axe, Super Slender Axe, Upright Fruiting Offshoots, and Kym Green Bush. In 2016, whole tree renewal of the four systems was studied with ‘Benton’ cultivar on three rootstocks of varying vigor: Gisela 3, Gisela 5, and Gisela 6. During bloom, all fruit-bearing components of the canopy were pruned back to stubs close to the permanent structure. TSA resulted in the higher number of shoots, while KGB and UFO had the longest average shoot length. The results indicate that each canopy system-rootstock combination refilled canopy space, except for KGB on each rootstock, to quickly regenerate fruiting sites.
Read
