2014 ASHS Annual Conference

In 2006 we planted a 1 ha field trial which compared 7 Geneva rootstocks (G.16, G.41, G.11, G.935, G.4210, G.6210 and G.30) along with B.9, M.9, M.26 and M.7 as controls with Gala and Honeycrisp as the scion varieties.  Each rootstock was trained to 4 high-density systems: Slender Pyramid (840 trees/ha), Vertical Axis (1284 trees/ha), Slender Axis (2244 trees/ha), and Tall Spindle (3262 trees/ha). Within the Tall Spindle system we compared fully feathered nursery trees (2 years in the nursery) and bench-grafted trees (no time in the nursery but directly planted to the field after grafting). Cumulative yields (years 1-8) were highest for the Tall Spindle system followed by the Slender Axis, Vertical Axis and Slender Pyramid which had the lowest yield.  The bench-grafted trees had much lower early yield than the fully feathered trees. Among rootstocks, G.16, G.11, G.41 and M.9 had the highest yield with Gala while B.9 had lower yield. With Honeycrisp, G.16, B.9, G.11 and M.9 had the highest yield while G.41 had lower yield.  An economic analysis using the first 8 years of yield data and estimated yield through year 20 showed that the Tall Spindle system was the most profitable systems followed by the Slender Axis, Vertical Axis and the Slender Pyramid.  Among tree types, the feathered trees were more profitable over 20 years than the direct-plant bench grafts despite the much lower initial cost of the bench grafts.