PERFORMANCE OF FOUR HIGH DENSITY APPLE ORCHARD SYSTEMS WITH 'FUJI' AND 'BRAEBURN'

A trial of four supported apple orchard systems, Tatura Trellis (60° angled palmette), Guttingen-V (70° angled spindle), and vertical double row, each at a density of 2,500 trees/ha and HYTEC (hybrid tree cone) at 1,667 trees/ha were established with ‘Fuji’ on M.9 and ‘Braeburn’ on M.26 rootstock in Wenatchee, WA, USA. The four orchard systems were randomized within varieties and replicated in five blocks. Each replication of a variety/orchard system treatment consisted of 12 trees except the double row and HYTEC which had 8 trees. Half the trees of each variety/orchard system plot were trained to 3 m height and half to 2 m height. Data for years 7, 9 and 10 are presented. Tree size measured as cm² trunk cross-sectional area (TCA) for the Tatura Trellis was smaller than the other three orchard systems. Tree height had no effect on final TCA. Light interception (%) for the HYTEC system was lower than the other three orchard systems and was lower for 2 m tall trees than 3 m tall trees. Yield (t/ha) in years 7, 9 and 10 was similar for the three systems at 2,500 trees/ha density while yield of the HYTEC system was lower in proportion to its lower tree density. With both varieties and all orchard systems, 3 m tall trees had higher yield than 2 m tall trees. With both varieties, cumulative yield from year 2 for the three orchard systems at 2,500 trees/ha was similar and significantly greater than for HYTEC at years 7, 9 and 10. The 3 m tall trees also had significantly higher cumulative yield than 2 m tall trees. Cumulative yield efficiency (kg/cm²) of Tatura Trellis trees was higher than for the three other orchard systems due to smaller tree size.