Annual, off-season raspberry production in warm season climates

There is increasing interest in red raspberry (Rubus idaeus) production worldwide due to increased demand for both fresh and processed fruit. Although the United States is the third largest raspberry producer in the world, domestic demand exceeds supply, and the shortage in fresh market raspberries is filled by imported fruit from Canada during July and August, and from Mexico and Chile during November through May. The raspberry harvest season is well defined and the perishability of the fruit limits postharvest storage. Winter production of raspberry in tropical and subtropical climates could extend the harvest season and allow off-season fruit production during periods of high market prices. The objective of the current study was to examine growth and yield of red raspberry cultivars grown in an annual winter production system in Florida and Puerto Rico. Long cane cultivars were purchased from a nursery in the Pacific north-western U.S. in 2002 ('Heritage' and 'Tulameen'), 2003 ('Tulameen' and 'Willamette'), and 2004 ('Tulameen' and 'Cascade Delight') and planted in raised beds in polyethylene tunnels in December (Florida) or under an open-sided polyethylene structure in January-March (Puerto Rico). In Florida, harvest occurred from approximately mid-March through the end of May, while in Puerto Rico, harvest occurred from the end of March through early June (except in 2002, when canes were planted in March). Yields per cane varied with cultivar, but ranged from approximately 80 to 600 g/cane for 'Tulameen', 170 to 290 g/cane for 'Heritage', 135 to 350 g/cane for 'Willamette', and approximately 470 g/cane for 'Cascade Delight'. Economic analysis suggests that, at this point, returns on this system would be marginal. However, increasing cane number per unit area and increasing pollination efficiency may increase yields, while planting earlier would increase the return per unit. The key to success may hinge on developing a system where multi-year production is feasible in a warm winter climate.