1a. Objectives (from AD-416):
1. Enhance productivity in strawberry. 2. Enhance blackberry yield and survival.
1b. Approach (from AD-416):
Small fruits require high labor and chemical inputs. Improvements in cropping efficiency and out-of-season fruit production of strawberries and blackberries are needed to foster commercial expansion of these small fruits and help mitigate production factors limiting profit potential. In the current global economic market, it is difficult for the small fruit industry in the United States to maintain a profitable operation with ever-increasing competition and market share by fruits being imported from countries to the south. Studies will be conducted to: 1) determine the efficacy of novel cultural and chemical treatments to mitigate low temperature damage, and effects of primocane and environmental manipulations to accelerate and intensify floral bud initiation and subsequent reproductive development, 2) improve the understanding of mechanisms controlling flower development in strawberry and blackberry, and growth processes involved in regulating the flower size and inflorescence development, and 3) analyze the effects of plant material source and environmental conditions during transplant propagation to devise management strategies aimed at producing high quality, superior yielding strawberry transplants. Research into alternative production systems and evaluation of novel germplasm materials is expected to provide new technology and to create new opportunities to produce blackberries for fresh market. Research on season extension techniques for strawberries will provide new technology for the management of strawberries without the need for pre-plant soil fumigation and also opportunities to produce strawberries from October to December in the mid-Atlantic coast region. Technology transfer efforts proposed in this project are expected to improve viability of small fruit farming and rural vitality in several regions of the United States.
3. Progress Report:
Under Objective 1, we made significant progress in evaluating strawberry plants resulting from crossing 'Chandler', 'Sweet Charlie', and 'Strawberry Festival' for fall flowering potential. Runner tips of 14 selections were harvested in early July 2011 to make transplants using a greenhouse propagation method developed by ARS researchers in Kearneysville, WV. The rooted transplants were established in a replicated field study in September 2011 under high tunnels. Of the 14 off-springs, 4 were identified to have good flower development in October, November, and December, and selected for advanced trials. Development of superior strawberry plants that are capable of flowering in fall will enable growers in the mid-Atlantic coast region to have plants that will produce fruit from fall to winter and from spring to summer. Double cropping strawberry plants will make strawberry production in this region more sustainable. Under Objective 2, we made significant progress in enhancing blackberry productivity in more northern climates. Demonstration plots were established in USDA Plant Hardiness Zone 5 in Iowa and Pennsylvania using the Rotating Cross Arm Trellis technology developed by ARS researchers in Kearneysville, WV. With this technology, blackberry plants can be laid down close to the ground and covered with floating rowcover in the winter. Winter survival of blackberry plants grown with this technology was excellent. In the spring after flower shoots emerged, the entire canopy was covered again with floating rowcover to protect plants from the spring frost. This treatment was highly effective in protecting blackberry plants in Iowa. Little spring frost damage occurred in treated plants compared to more than >90% damage in uncovered, control plants. These findings will lead to widening the opportunities to produce blackberries for fresh market outside their traditional geographic zones and temporal restrictions and seasons.
1. New improved technology for producing long-cane blackberry plants. The U.S. blackberry growers want to produce out-of-season blackberries. ARS researchers at Kearneysville, West Virginia, used a unique trellis and cane training system to propagate many long-cane plants which can be manipulated to produce off-season fruit which command a higher price. The new propagation system increased plant output five- to seven-folds over the current commercial propagation technique. The new innovations include long-cane plants that are rooted at both ends of the cane. These long cane plants produced more fruit clusters, clusters with more fruit, larger fruit, and 250% increase in fruit production compared to long-cane plants produced by traditional methods. The new method was published in 2011 in HortTechnology to broadly disseminate the information to users. The new propagation method is efficient for producing a large number of long-cane blackberry plants and should be useful to both growers and nurserymen.
Takeda, F., Soria, J. 2011. Method for producing tip-layered, long-cane blackberry plants using the rotating cross-arm trellis and cane training system. HortTechnology. 21(5):563-568.