Investigating the possibility of fruiting primocane raspberries for off-season production in Cyprus.

Dormant single cane (15 cm) plants of 'Autumn Bliss' and 'Polana', primocane-fruiting red raspberry (Rubus idaeus L.) plants from the UK, were sent to the Agricultural Research Institute of Cyprus in December 2001 after they had already received an unknown amount of field chilling (x days). The plant material after arrival was additionally chilled at 4 degrees C in order to escalate the production and to ensure an adequate fruiting since for raspberry production chilling plays a significant role. The treatments were x, x+16 and x+32 days of chilling. Afterwards the plants were planted in a soilless plant bed system in an unheated plastic greenhouse. The planting density was 4.1 canes m(-2). 'Autumn Bliss' had greater cane vigour, flowered earlier, and produced a higher yield with acceptable berry mass, while 'Polana' did not produce flowers in time to yield a sufficient crop before summer (21 June 2002). The additional chilling (AC) reduced cane length, node number, and leaf area for both cultivars but no clear influence was observed on internode length, cane diameter and time to flowering. AC increased the number of fruiting nodes and berry mass for 'Autumn Bliss', whereas this result was not the case in 'Polana'. Our study confirms the hypothesis that raspberries can grow and be produced efficiently in the semi-arid climate of Cyprus. These results also imply that there may be a good prospect for an off-season production system for primocane-fruiting red raspberries in Cyprus and Southern Europe.