Primocane Blackberries Open New Markets for Fruit Growers
The Problem
Traditional, floricane-fruiting blackberry plants produce canes that only fruit every other year, and are typically limited to a 4-6 week growing season.
The Research
Blackberry plants have perennial root systems that survive from year-to-year, while the canes they produce are biennial with a lifespan of two growing seasons. First-year canes produced by the plant are called primocanes. If the climate allows, primocanes overwinter and are called floricanes in their second season. Until 2004, all commercially-available blackberry plants were of the floricane-fruiting variety in which only the floricanes flower and produce fruit while primocanes grow for the next year.
Following the discovery of a primocane-fruiting genetic trait in a wild blackberry plant, John Clark, a Division of Agriculture fruit breeder, began the slow process of breeding commercially-viable, primocane-fruiting blackberries. Since the first primocane-fruiting blackberry plant selections were made on September 27, 1997, Clark has worked to improve the primocane-fruiting trait and incorporate it into the Division’s blackberry breeding program.
Clark and his team of fruit breeders utilized traditional breeding methods to gradually develop primocane-fruiting cultivars with diverse flowering times, thornlessness and high fruit quality and productivity. Notable varieties include Prime-Ark® 45, Prime-Ark® Freedom and Prime-Ark® Traveler, the Division’s latest primocane-fruiting release and the world’s first shipping-quality, thornless, primocane-fruiting cultivar.
The Bottom Line
The development of primocane-fruiting blackberry cultivars opens the door to a longer blackberry growing season and expands viable blackberry production areas. Additional research is needed to develop exact growing methods for homeowners, local markets and commercial producers, and to adapt the technology to diverse growing conditions.
The Researcher
John R. Clark
Distinguished Professor, Horticulture Department
University of Arkansas System Division of Agriculture fruit breeder.
Clark earned his bachelor’s and master’s degrees from Mississippi State University. He earned a Ph.D. from the University of Arkansas in 1983.
Clark leads the Division’s fruit breeding program and his research focuses on the breeding and cultivar development of blueberries, blackberries, and grapes.
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