Method for Producing Long-cane Blackberry Plants

The objective of this study was to evaluate primocane cane training and propagation techniques for the production of long-cane blackberry (Rubus spp.) plants. Seventeen to 29 6-ft-long canes were produced from each semierect ‘Triple Crown’ and trailing ‘Siskiyou’ blackberry plant grown on the rotating cross-arm (RCA) trellis and cane training system. By early August, the lateral canes had grown beyond the top wire 6 ft above the ground and continued growing downward to the ground. The tips of the lateral canes reached the soil level from mid-August to mid-September at which time they were placed in 1/2-gal pots containing peatbased media. In early Oct. 2009, the tip-rooted lateral canes were cut from the stock plant at the uppermost trellis wire. Among the long-cane plants produced in 2009, 76% of buds in ‘Siskiyou’ broke, but less than 30% of buds in ‘Triple Crown’ broke in a heated greenhouse. Flowering occurred in 15% of the shoots that developed on rooted ‘Siskiyou’ long canes, but the shoots on the long-cane plants of ‘Triple Crown’ were morphologically vegetative and flowering did not occur. In 2010–11, the long-cane plants were detached from the stock plants in December, January, and March. The numbers of nodes with a flowering shoot improved to 41% and 16% and the number of flowers per shoot increased to two and five flowers on long-cane plants of ‘Siskiyou’ and ‘Triple Crown’ blackberry, respectively.