Results from previous cultural and physiological studies of red raspberry suggest that primocanes compete with floricanes for light, nutrients and/or photoassimilates. This study was undertaken to determine whether this competition might be reflected in the actual translocation of photoassimilates between the two types of canes. In 1993, pairs of greenhouse grown, potted red raspberry (Rubus idaeus L.) plants contaming one or two floricanes and numerous primocanes were labeled with 14CO2 on four dates corresponding with early anthesis, green fruit, red fruit and post fruit maturity stages of the growing season. For each experiment, either a floricane or a primocane was exposed to 92.5μCi 14CO2 within a sealed bag. After 24 hours, the bag was removed and the presence of label was monitored for up to 11 days. Activity was determined using liquid scintillation. At all developmental stages 14C moved from the labeled floricane to primocanes that were from 2.5 cm to 1.5 m tall and to the roots. Movement was quickest and relatively greatest at early anthesis, dccreascd during fruiting, and was still occuring at 2 months after fruit maturity. Small amounts of label were detected in roots of labeled primocanes at all stages, but trace amounts were present in fruit and other primocanes only at post fruit maturity.
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