BLACKBERRY PRODUCTION SYSTEMS - A WORLDWIDE PERSPECTIVE

There are generally three types of blackberry: the erect (e.g. ‘Navaho’, ‘Ouachita’); semi-erect (e.g. ‘Chester Thornless’, ‘Loch Ness’); and trailing (e.g. ‘Marion’, ‘Boysen’). All types can be grown for fresh and processed markets, although the trailing types with their small seed (pyrene) size and aromatic flavor are considered superior for processed markets. The largest blackberry production regions are Mexico, Europe (particularly Serbia), and the USA (particularly Oregon) where the predominant types grown are erect, semi-erect, and trailing, respectively. Production systems for these types of blackberries differ with modifications in some regions depending on historical production differences, cultivar, and harvest method. Trailing blackberries are generally trained to a two- to three-wire trellis. Primocanes are either carefully managed under the canopy for every-year production or are left un-managed in the on-year of alternate year (AY) production systems. AY production systems are most common in Oregon where they are used to maximize cold tolerance and minimize cane disease. Primocane suppression techniques are used to maximize machine-harvest efficiency, while training techniques can be utilized to increase yield and cold hardiness. Erect blackberries are generally grown in hand-harvested fresh market production systems. The type of trellis used, the extent of cane training (tying or no tying), and the degree of main cane tipping and the amount and frequency of branch cane shortening in erect blackberry varies with region. In Mexico, specialized production systems, which use chemical defoliants, pruning, and growth regulators, have been developed to extend the season for erect blackberry cultivars such as ‘Tupy’. Semi-erect blackberries are generally grown on a more elaborate trellis, sometimes with a divided canopy. Depending on production region, primocanes may be summer pruned to a high (~1.7 m) or low (~0.5 m) height to encourage branching; management of branches differs among regions. Recently, annual-fruiting, erect blackberries have being trialed by commercial growers in many production regions. Early evidence indicates this type of blackberry may offer advantages for out-of-season production in warmer climates, provided the plantings are pruned and managed well. As demand for blackberries continues to increase, new cultivars are being developed including primocane- or annual-fruiting, erect types and hybrids between erect, semi-erect, and trailing types that require modifications in the traditional pruning and training systems.