B.H. Barritt, J.A. Barden, J. Cline, R.L. Granger, E.E. Hoover, M.M. Kushad, R.P. Marini, M. Parker, R.L. Perry, T. Robinson, C.R. Unrath, M.A. Dilley
Ten orchard system treatments were evaluated: slender spindle training (SS) with rootstocks M.9, Mark and B.9 at 2460 trees/ha, vertical axis training (VA) with rootstocks P.1, M.26, 0.3, M.9 and Mark at 1502 trees/ha, and central leader training (CL) with rootstocks M.26 and Mark at 1111 trees/ha. 'Empire' was the scion at 8 sites (Illinois, Michigan, Minnesota, New York, North Carolina, Ontario, Quebec, Virginia), 'Jonagold' at 5 sites (Illinois, Michigan, New York, Ontario, Quebec), 'Delicious' at 3 sites (Minnesota, North Carolina, Virginia) and 'Fuji' at 1 site (Washington). Ten-meter-long plots of each treatment were replicated four times in a RCB design at each site. At the end of year 5, trunk cross-sectional area (TCA, cm2), cumulative yield (kg per tree and tonne per ha) and cumulative yield efficiency (kg/cm2) were determined. With 'Empire' and 'Jonagold', there were significant site, orchard system treatment, and site X treatment effects for each trait. With each cultivar and at most sites, VA/P.1, VA/M.26 and CL/M.26 trees had the largest TCA. Treatments with the lowest tree density, CL/M.26 and CL/Mark, had the lowest cumulative production (t/ha) at almost all sites while treatments with the highest tree densities (SS) had the highest yield at most sites. Lowest yield efficiency (kg/cm2) occurred for treatments with P.1 and M.26 rootstocks and the highest yield efficiency occurred with VA/M.9, VA/O.3 and VA/Mark with each cultivar and at most sites.
Barritt, B.H., Barden, J.A., Cline, J., Granger, R.L., Hoover, E.E., Kushad, M.M., Marini, R.P., Parker, M., Perry, R.L., Robinson, T., Unrath, C.R. and Dilley, M.A. (1997). NORTH AMERICAN NC-140 APPLE ORCHARD SYSTEMS TRIAL. Acta Hortic. 451, 443-452
DOI: 10.17660/ActaHortic.1997.451.50

Acta Horticulturae