Author
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Takeda, Fumiomi |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 8/11/2015 Publication Date: 8/14/2015 Citation: Takeda, F. 2015. Challenges and opportunities for growing blackberries in areas with adverse environmental conditions [abstract]. Second Chilean Congress on Berries. p. 6-7. Interpretive Summary: Technical Abstract: The rotating cross-arm (RCA) technology (Fig. 1) combines a unique trellis design and cane training protocol. Developed over the last two decades, this technology is beginning to have an impact on the blackberry (Genus Rubus, subgenus Rubus) industry in the United States of America (USA). It has been successfully transferred to growers in more than 25 states in the last four years and contributed to increasing the blackberry acreage by about approximately 150 ha in the eastern USA. Our research and development effort on the RCA technology and recent commercialization of this growing system by Trellis Growing Systems (Ft. Wayne, IN USA) has shown that 1) winter injury can be reduced by modifying the crop environment and production techniques, 2) white drupe formation can be reduced when fruit is positioned away from direct sunlight, and 3) harvest efficiency is improved when the fruit is positioned on one side of the row. Our research has also shown that RCA technology can be used to generate several times more one-node floricane cuttings and long-cane plants than traditional propagation methods (Fig. 2). The enclosure technique improved rooting of some cultivars but there were recalcitrant cultivars like ‘Apache’. Consistent production of blackberries was achieved in areas with minimum winter temperatures below negative 22 degrees C with the RCA technology. This technology allows the canes to be positioned close to the ground in winter and covered with a floating rowcover (Fig. 3). An unexpected result of this winter protection system was some leaves on the floricane remained green throughout the winter and spring and were photosynthetically functional when growth resumed under warmer conditions of greenhouse. More recently, the RCA technology has been evaluated for growing red raspberries under Nordic conditions (R. Nestby, pers. comm.). In Norway, the floricane of red raspberries often suffer 20-30 percent injury from exposures to low temperatures. In a cooperative project, Bioforsk and USDA implemented methods to improve winter survival of red raspberry (Fig. 3). We studied from 2011 to 2014 the bending and covering effect of red raspberry floricanes of ‘Glen Ample’, ‘Stiora’ and selection KV91-39-7 on winter injury and yield. Canes were trained to a rotating cross-arm (RCA) trellis system and covered with two layers of polyethylene sheets, and supplemental heat was provided at critical temperatures. Bending plus heating reduced freezing injury of buds for all cultivars, and tended to increase yield for ‘Stiora’ and KV91-39-7, but not for ‘Glen Ample’. Plots lifted directly to vertical after winter covering yielded more than plots where canes were left horizontal until anthesis and then lifted to vertical. The experiments show that bending raspberry canes to avoid freezing injury was possible without much visible cane injury if bending was undertaken carefully using a RCA trellis. However, standard trellising with erect canes improved fruit yield. It was found that a few more cane buds were torn off (less than two percent) compared to canes in erect position. See attached document with figures. |
