Browsing by Subject "long cane plants"

Red raspberry (Rubus idaeus L.) is one of the most important berry crops economically in Finland but the profitability is weakened due to frequent winter injuries and varying yields. Protected berry production has lately become the main cultivation method of raspberries in Europe. Long cane raspberry is a special plant type that has been induced to flower and cold stored to produce a harvest in the year of planting. Specifically designed for protected cropping raspberry long canes have been shown to possess a very high cropping potential. The aim of this study in the first experiment was to examine the effect of growing conditions, primocane and floricane number and storage time on yield of red raspberry long canes. Raspberries were grown in an open field and in a tunnel with varying cane numbers (1 or 2). After cold storage they were forced in a plastic tunnel and new shoots were allowed to grow alongside the floricanes. The canes grown in a tunnel yielded 56 % more compared to those grown outdoors. The plants with two floricanes yielded 39 % more compared to plants with only one floricane but their average berry weight was 0,6 g lower. Presence or absence of primocanes didn’t have an effect on the yield or other growth parameters of the floricanes. In the second experiment plants were grown in an open field and in a tunnel and cold stored for three different periods of 4, 12 or 20 weeks. After storage the plants were forced to flower in a greenhouse. The cropping potential of the plants stored for 20 weeks (977 flowers/plant) was almost three times as high compared to those stored for only 4 weeks (332 flowers/plant). Plants that had been stored for 20 weeks also produced 138 % more laterals that were 14 % longer than plants stored for 4 weeks. Bud break for plants stored for 20 weeks took place 25 days earlier than for those stored for 4 weeks. Carbohydrate content of raspberry cane is related to its ability to produce a harvest. In this experiment the concentration of soluble carbohydrates increased and the concentration of starch decreased during storage. The total carbohydrate content in the whole plant also decreased during storage and it was 12-40 % higher in plants grown in a tunnel compared to the ones grown in an open field. According to this research it is possible to increase raspberry yields with long cane plants. In the two experiments growing conditions and storage time were found to have the biggest influence on cropping potential. The most optimal long cane plant type based on this research would be a plant with two canes that has been grown in a tunnel and cold-stored 20 weeks at the minimum.