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United States Department of Agriculture

Agricultural Research Service

Research Project: Physiology and Genetic Improvement of Small Fruit Crops Title: High Tunnel versus Open Field: Management of Primocane-fruiting Blackberry Using Pruning and Tipping to Increase Yield and Extend the Fruiting Season

Authors
item Thompson, Ellen -
item Strik, Bernadine -
item Finn, Chad
item Zhao, Yanyun -
item Clark, John -

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 16, 2009
Publication Date: October 1, 2009
Citation: Thompson, E., Strik, B., Finn, C.E., Zhao, Y., Clark, J.R. 2009. High tunnel versus open field: management of primocane-fruiting blackberry using pruning and tipping to increase yield and extend the fruiting season. HortScience. 44(6):1581-1587.

Interpretive Summary: Primocane-fruiting blackberries may offer opportunities for season extension and off-season fruit production, particularly in mild climates with protected cultivation. In May 2005, plants of ‘Prime-Jan’® were established at the Oregon State University - North Willamette Research and Extension Center, Aurora, Ore. (NWREC). Half of planting was established under a high tunnel and the remainder planted in an adjacent open field. In 2006-2007, primocanes were subjected to four pruning treatments to promote branching and/or delay harvest: 1) re-cut primocanes to just above the crown once reaching 0.25 m, then soft-tip the subsequent canes at 0.5 m; 2) re-cut primocanes at 0.5 m, then soft-tip at 0.5 m; 3) double-tip canes (soft-tip main cane at 0.5 m, then soft-tip branches at 0.5 m); and 4) soft-tip the main cane at 0.5 m (control). Plastic was placed on the top of the tunnel from 5 Sept. 2006 and 31 Aug. 2007, about 1 to 2 weeks before harvest, until the end of harvest to protect fruit from inclement weather. Primocanes that were double-tipped had nearly twice the flowers and fruit than canes that were soft-tipped only once. Primocanes that were double-tipped produced heavier fruit than other pruning treatments – 33% heavier than the control, on average. Double-tipped primocanes did not have more ovules per flower, but had significantly more drupelets set compared to the control. In addition, plants growing under the tunnel tended to produce heavier fruit (32%, on average) than those grown in the open field. The pruning systems used here increased yield and offered options for season extension.

Technical Abstract: Primocane-fruiting blackberries may offer opportunities for season extension and off-season fruit productionivation. ‘Prime-Jan’® plants were established at the Oregon State University - North Willamette Research and Extension Center, Aurora, Ore. (NWREC). Half of the planting was established under a high tunnel and the remainder planted in an open field. Primocanes were subjected to 4 pruning treatments: 1) re-cut to just above the crown once reaching 0.25 m, then soft-tip the subsequent canes at 0.5 m; 2) re-cut at 0.5 m, then soft-tip at 0.5 m; 3) double-tip canes (soft-tip main cane at 0.5 m, then soft-tip branches at 0.5 m); and 4) soft-tip the main cane at 0.5 m (control). Plastic was placed on the top of the tunnel from 5 Sept. 2006 and 31 Aug. 2007 until the end of harvest to protect fruit from weather. Fruit harvest began on 12 Sept. in the open field and tunnel, but lasted about 3 weeks longer in the tunnel, ending on 16 Nov. Primocanes that were double-tipped had nearly twice the flowers and fruit than canes that were soft-tipped only once. In the tunnel, cumulative yield of double-tipped primocanes averaged 10.7 t·ha-1 in 2006 and 19.3 t·ha-1 22 in 2007. On average, cumulative yield for double-tipped primocanes was 47% less in the open field than in the tunnel. Harvest was not delayed in canes that were re-1 cut at 0.25 m in 2006, compared with the control and the double-tipped treatment; however, harvest was delayed by 2 weeks in 2007 in this treatment. In contrast, harvest was delayed by about 4 weeks when primocanes were re-cut at 0.5 m. Primocanes that were double-tipped produced heavier fruit than other pruning treatments – 33% heavier than the control, on average. Double-tipped primocanes did not have more ovules per flower, but had significantly more drupelets set compared to the control. In addition, plants growing under the tunnel tended to produce heavier fruit than those grown in the open field. Although fruit under the tunnel was protected from rain, TSS, pH, TACY, and total phenolics began to decline in late October in both years, likely due to cool night temperatures and low light conditions.

Last Modified: 10/21/2014
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