Methods for Producing Long-cane Blackberry Plants

U.S. blackberry (Rubus) growers need to find ways to expand market share by entering specific niches.  Production of blackberries in off-season is one desired approach. However, with the high investment for protected cultivation systems, yield in the first year of production is desirable to obtain a quick return on the investment.  A variety of techniques and vegetative materials have been used to asexually propagate blackberries.  We used a unique trellis and cane training system to propagate 2-m-long cane plants with roots at the distal end and 4-m-long looped cane plants with roots at both ends.  The new propagation system increased plant output five- to seven-fold over the current commercial propagation technique.  By inducing root formation at both ends of 4-m-long primocanes, % budbreak, number of flowering shoots per m cane length, and number of fruit per cluster were increased. The long-cane plants can be established in a warm area, such as southern Florida, in late winter to obtain a crop in March and April. For late season fruit production, plants are held in cold storage until summer and then grown in a warm environment so that the fruit matures from August to October. This new propagation method is efficient for producing a large number of blackberry plants that can be manipulated to produce fruit in the off-season and is therefore useful to both growers and nurserymen wishing to produce container plants for off-season fruit production.