1a.Objectives (from AD-416)
This project focuses on two main research areas:.
1)breeding to develop superior small-fruit germplasm and cultivars, and.
2)the identification and characterization of disease resistance in small-fruits. Specifically, the breeding research is directed at originating improved small-fruit germplasm and cultivars that combine resistance to the prevalent diseases of several growing regions along with the highest productivity and fruit quality possible. The pathology studies are targeted at developing improved disease screening methods, identifying and evaluating disease resistant germplasm, and developing improved methods of incorporating resistances into superior germplasm. The two objectives are closely related, and are often carried out in concert. Both aspects are necessary to provide new varieties that will benefit small-fruit growers and consumers. In addition, the project will evaluate parthenocarpic potential in rabbiteye blueberry.

1b.Approach (from AD-416)
Small fruit germplasm from established cultivar materials to wild types will be evaluated using both classical and molecular techniques. Scientists will develop improved disease screening methods, identify and evaluate disease resistant germplasm, and develop improved methods of incorporating the resistance into superior germplasm. Genetic aspects of both pathogen and host variation will be studied. Concurrent with selection for disease resistance, breeding will emphasize selection for other factors necessary to the development of successful cultivars, with particular emphasis on fruit quality and phytonutrients, environmental adaptation, and adaptation to mechanization. Vaccinium (blueberry and cranberry) breeding and disease work will be carried out at Chatsworth, New Jersey, and Fragaria (strawberry) and Rubus (blackberry and raspberry = brambles) work will be carried out at Beltsville, Maryland.

3.Progress Report
Research was conducted under National program 301 (Plant Genetic Resources,, Genomics and Genetic Improvement), Action Component 3 (Genetic Improvement of Crops). This project contributed significant information regarding fungal diseases, resistance to fungal diseases, and viral diseases in blueberry. Among the accomplishments were: identification of a new species of Phytophthora, identification of the causal agent of a new disease syndrome in blueberry called ‘Black Shadow’, identification of sources of resistance to stem blight and Phomopsis twig blight in blueberry, identification of sources of resistance to anthracnose fruit rot among one hundred screened blueberry cultivars, and identification of blueberry cultivars with good resistance to both foliar and fruit forms of anthracnose disease. Work was also completed that documented the impact of Fairy ring disease of cranberry on host genotype, and that documented the symptomatology of Red ringspot virus in Vaccinium spp. In strawberry, seedling screens for strawberry diseases were developed. This project also contributed significant information regarding the effects of genotype, environment, and storage regimes on antioxidants and other fruit quality characteristics. Among these accomplishments were: evaluations of antioxidants in strawberries, blueberries, and lingonberries, evaluations of anti-carcinogenic compounds in blackberries and black raspberries, and evaluations of the effects of modified atmosphere conditions, oxygen, natural volatiles, and methyl jasmonate on antioxidants, anthocyanins, and phenolics during cold storage of small fruit. Studies were also conducted that measured the resveratrol content in strawberry, the fruit quality of organic versus conventional blueberry fruit, the effects of temperature on strawberry lipids, the volatiles of blueberry fruit, the fruit quality of red raspberry fruit, and the fruit quality of blueberries as compared by taste panels versus instrumental analysis. Another set of studies evaluated cold hardiness in multiple blueberry genetic types. These studies evaluated highbush, southern highbush, rabbiteye, rabbiteye hybrids, and Vaccinium constablaei, with the goal of finding germplasm to develop more broadly adapted blueberry cultivars. Other projects included studies of parthenocarpy in highbush blueberry, self-fertility in rabbiteye hybrids, yield relationships in highbush blueberry, strawberry production systems, and heat-unit models for predicting flowering dates in blackberry. Two pink-fruited blueberry cultivars released in response to requests from the nursery industry.

4.Accomplishments
1. Protocols and statistical analyses for determining strawberry post-harvest quality developed. Breeeding programs typically evaluate fresh market quality, but often there are no good measures for post-harvest quality characters. ARS scientists at Beltsville, Maryland, incorporated into an on-going strawberry breeding program new protocols and statistical analyses for determining post-harvest quality. This research will improve the ability to select future strawberry cultivars for post-harvest quality and will result in better-storing berries. This research is under National Program 301, Component 3, Problem statement 3C.

2. Strawberry production systems developed. Most strawberry production systems are currently designed for main season, matted row production. ARS scientists at Beltsville, Maryland, and Kearneysville, West Virginia, developed novel production systems and strawberry genotypes for summer-fruiting strawberries and for fall-fruiting strawberries. This research will aid in the development of new strawberry production systems to expand markets and marketing windows. This research is under National Program 301, Component 3, Problem statement 3C.

3. Relationship of yield, berry weight, and pollination effectiveness established in highbush blueberry. Growers often wonder whether small berry size means that pollination was less than optimal. A study was completed that documented the relationship between yield, berry weight, and pollination effectiveness, as measured by seed number, in two major highbush blueberry cultivars. This study demonstrated that across a 10 year period there was no correlation between yield and berry weight, but that seed per gram of fresh weight was correlated to total yield. The study showed that although berry weight has been shown to be correlated to seed number, for the cultivar ‘Duke’, berries with similar seed numbers varied in as weight as much 86% between years. This research aids in understanding the parameters that affect and may contribute to improvement of total marketable yield by allowing growers to concentrate on critical yield-related factors. This research is under National Program 301, Component 3, Problem statement 3C.

4. Fairy ring disease of cranberry impacts host genotype. Fairy ring is a fungal disease that kills plants in an expanding a circle. Circle centers reestablish, but often their productivity is poor. We demonstrated through DNA fingerprinting that as fairy ring disease sweeps through an infected cranberry bed, the primary cultivar, which is typically clonal, is largely killed. This allows seedlings with other genetic backgrounds to establish, and over time the cultivar is lost in areas devastated by the disease. This dramatically reduces yield potential in the affected cranberry beds. Surviving seedlings are likely to be more resistant to the disease, thus providing a source for germplasm resistance screening. This information suggests that growers may wish to replant areas affected by the disease, but also suggests that recolonizing plants may be useful for resistance breeding. This research is under National Program 301, Component 3, Problem statement 3C.

5. Resveratrol in strawberry. Resveratrol is a plant compound that has been shown to have anti-cancer, anti-inflammatory, blood-sugar-lowering, and other beneficial cardiovascular effects. Strawberries contained two forms of resveratrol and many factors affected the amount of resveratrol in strawberry fruit. Genotype variation, degree of ripeness, compost, mulch, atmospheric carbon dioxide concentration, growth temperature, growth regulator treatment all affects resveratrol content. This suggests that both genetic background and cultural practices have potential to influence antioxidant capacity in crops and that strawberries may serve as a dietary source of resveratrol to enhance human health. This research is under National Program 301, Objective 1, Component 3, Problem statement 3C.

6. Antioxidant enhancement of blackberries by methyl jasmonate. Treatment with methyl jasmonate, a naturally-occurring chemical produced by plants, increased flavonoids, other antioxidants and secondary metabolites in blackberries. Methyl jasmonate treated fruit also had higher anti-cancer activities than berries that had not been treated. Furthermore, methyl jasmonate improved fruit quality by increasing sugar content and lowering acid levels. These results indicate that consuming blackberries may be beneficial to human health and methyl jasmonate treatment could enhance their health benefits. This research is under National Program 301, Objective 1, Component 3, Problem statement 3C.

5.Significant Activities that Support Special Target Populations
Cooperator on a USDA/1890 grant proposal on “Anti-diabetic properties of grape and other berry pomace” with Virginia State University. Award by the American Chemical Society (ACS) to train one SEED student on methods of analyzing antioxidant capacity and fruit quality in berry fruits for the Summer of 2008.

6.Technology Transfer

Number of Non-Peer Reviewed Presentations and Proceedings	9
Number of Newspaper Articles and Other Presentations for Non-Science Audiences	3

Review Publications
Erkan, M., Wang, S.Y., Wang, C.Y. 2007. Effect of UV treatment on antioxidant capacity, antioxidant enzyme activity and decay in strawberry fruit. Postharvest Biology and Technology. 48:163-171.