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:
Significant progress has been made in developing a production technique to enhance growth and fruiting in day-neutral strawberry cultivar by altering the temperatures of rooting medium during winter months. Experiments were carried out to reduce disease incidence using novel, non-chemical methods to make a fungus incapable of causing fruit rot. The results of these studies would benefit the strawberry industry that spends as much as $3,000 per acre each year to control fungal diseases. Significant progress has been made in enhancing blackberry productivity and developing a new propagation method for blackberries. We used the rotating cross-arm (RCA) trellis and cane training system to increase the number long lateral canes. Methods were developed to improve rooting at both ends of long lateral canes to produce looped cane plants. The results indicated that looped cane plants were more productive than long-cane plants with roots at one end. Growth chamber studies showed a significant effect of temperatures on plant yield and harvest date. The commercialization of this technology will benefit a large number of small acreage farmers developing niche market for specialty crops, expand blackberry production into a sub-tropical region, and offer new ways to produce blackberries in out-of-season. The technology to develop these novel plant material was issued a patent (U.S. Patent No. 8,327,578 B1) entitled, "Process for the off-season production of blackberry". Alternative cane training systems for two USDA-ARS trailing blackberry (Black Diamond and Siskiyou) were grown with the RCA trellis system. Several selections of strawberry materials with high potential to produce fruit in fall and spring were propagated in the greenhouse and established in a low-tunnel production system in Beltsville, MD. The susceptibility of blackberry buds, flowers, and fruit to sub-zero temperatures was determined in a radiation frost chamber. The findings indicated that most flowers and fruit were damaged after 30 minutes at 27 degrees F. Injuries were expressed as discolored anther filament, petals, and the pistils (part of flower that develops into fruit). The rotating cross-arm trellis and winter protection system developed for expanding the blackberry production in the Midwestern states will be useful in mitigating spring frost. In event of a frost, this production system offers the means to position the flower shoots close to the ground and be covered with a floating rowcover which can provide some freeze protection (2 to 3 degrees F), thus, avoiding a crop loss from spring frost.
1. Blackberry acreage in the Midwest is expanding. Blackberry production in the Midwestern U.S. is limited by low winter temperatures that kill the fruit buds and vines, and spring frosts that kill flowers. ARS researchers at Kearneysville, West Virginia developed a Rotating Cross Arm Trellis System that allows the vines to be rotated to the ground and covered with a floating row-cover to protect the dormant vines from extreme temperatures. These same row covers can be used in the spring to protect the developing flowers from early spring frosts. This new production system reduces the risks of crop failure and major crop losses from extreme and untimely cold temperatures. Consequently, blackberry acreage for fresh market fruit production has grown from only a few acres to more than 200 acres in the last two years.
Yu, P., Li, C., Takeda, F., Krewers, G., Rains, G., Hamrita, T. 2013. Quantitative evaluation of a rotary blueberry mechanical harvester using a miniature instrumental sensor. Computers and Electronics in Agriculture. 88:25-31.