DEVELOPING AND EVALUATING INTENSIVE SWEET CHERRY ORCHARD SYSTEMS: THE NC140 REGIONAL RESEARCH TRIAL

A sweet cherry trial coordinated across North America (the NC140 project) was established in 2010 to integrate precocious rootstocks (of varying vigor levels) with intensive, pedestrian orchard canopy training systems suitable for different regions. The trial sites range from Mexico (Chihuahua/MX) to the United States (California/CA, Colorado/CO, Michigan/MI, Geneva New York/NY-G, New Paltz New York/NY-NP, Ohio/OH) to Canada (British Columbia/BC, Nova Scotia/NS). The rootstocks are Gisela 3 (very dwarfing), Gisela 5 (dwarfing), and Gisela 6 (vigorous), and the scions are ‘Benton’ (MI, CA, OH), ‘Regina’ (NY-G, NY-NP), ‘Skeena’ (BC, NS, MX), and ‘Early Robin’ (CO). The four intensive training systems under study have the developmental objectives of a) a maximum tree height that permits most orchard work without ladders, b) a tree structure with minimal permanent trunk or scaffold wood, and c) a canopy structure of fruiting wood that is relatively simplified, uniform, renewable, and balanced in leaf-to-fruit ratio. The systems are: 1) Kym Green Bush (KGB), a multiple leader bush with 15 to 20 upright fruiting units; 2) Tall Spindle Axe (TSA), a narrow single leader, with lateral fruiting units; 3) Upright Fruiting Offshoots (UFO), a fruiting wall comprised of an oblique, cordon-like leader with ~10 vertically-oriented fruiting units; and 4) Super Slender Axe (SSA), a fruiting wall comprised of closely-planted single leaders with short lateral fruiting units and severe annual pruning. The project objectives are to develop and compare these distinctly different sweet cherry canopy training strategies, determining their develop¬mental and performance interactions with both rootstock and environmental factors (climatic and edaphic). The results reported here represent the initial data from several sites for the orchard establishment phase (Years 1 to 3, planting to initial yield).