Influence of cane density and height on productivity and performance of red raspberry (Rubus idaeus L.) cultivar 'Glen Ample'

The cultivar 'Veten' has for many years been nearly the only red raspberry cultivar grown in Norway. The cultivation methods have therefore been developed and adapted to this cultivar. In later years the cultivar 'Glen Ample' has become the most used cultivar. This cultivar also grows vigorously, but has a different growth habit from 'Veten'. The primocanes grow taller and the laterals are longer so the rows are mostly very high and dense. An experiment was established to find the optimal cane height and density for growing high quality raspberry of this cultivar. The experiment was established in a four-year-old field with 'Glen Ample' in the spring of 2004. The canes were fixed to two wires that were 90 cm apart and every second cane was fixed to each wire. The canes were topped two buds above the wire, and the height of the wires was either 140 cm or 160 cm. Different cane densities were established by leaving 6, 8 or 10 canes per meter row at pruning early in the spring. There was no interaction between the experimental factors neither on berry size nor yield. The 20 cm difference in cane height did neither affect yield nor berry size. Cane density showed significant effects on yield. Crop per cane and per hectar increased with cane density. Berry size was not affected. The berries were, however, 20 per cent bigger the second year when the field was under polyethylene tunnels.