1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter?
Production of small fruit crops in the United States often is severely limited by various diseases. There is a need for research to develop varieties resistant to the major diseases. Our objective is to develop small fruit varieties (strawberry, black raspberry, thornless blackberry, blueberry, and cranberry) that combine resistance to common diseases of the eastern United States with the highest degree of fruit production, quality, and nutrition possible. We select disease resistant types for breeding new varieties, and develop improved disease screening methods to assure that our varieties are disease resistant under different growing conditions. We also study the interaction between the plants and the disease-causing organisms (fungi, bacteria, and other kinds of pathogens) to understand the mechanisms of infection and disease proliferation. This enables us to develop alternatives to chemical control.

Before the USDA began developing strawberry varieties with resistance to the red stele root rot disease, the production of strawberries in some parts of the country was not possible. Plant losses were nearly 100 percent. Resistant varieties have reopened these areas for strawberry production. Research needs to continue toward developing disease resistant varieties because of the threat of new races of the pathogen being introduced into production areas and the lack of chemical control for this disease. Similarly, Verticillium wilt and anthracnose of strawberry may severely limit fruit production. Anthracnose can be responsible for 80 100 percent fruit loss when weather conditions are favorable to the disease. The disease is particularly problematic in the annual raised ridge, plastic mulched production system. This system is rapidly replacing the traditional matted row production system in the southeast United States and portions of the Atlantic seaboard. The anthracnose disease cannot be adequately controlled with chemicals, but our recent progress shows that varieties can be developed that are resistant to the disease.

A 1994 survey of 44 states and six Canadian provinces where blueberries are grown listed mummy berry as the most common disease problem, and anthracnose fruit rot as the third most common problem. These concerns as well as the development of organic fruit production markets have highlighted the increasing need for resistant varieties. Economics of growing blueberry have also become a limiting factor as labor regulations have increased the difficulty of finding and keeping seasonal labor. There is an increasing need to have varieties suitable for machine harvest. The processing market, using berries for baked goods, freezing, juice, and jams, has also increased. Most berries harvested for processing have been either lowbush or third picking of highbush varieties, but now there is an increased interest in small-fruited highbush varieties strictly for processing.

This project has two specific goals:.
1)to develop small-fruit cultivars that combine disease resistance, broad environmental adaptation, high yield, and excellent fruit and plant quality characteristics, and.
2)to identify and utilize disease-resistant small-fruit genotypes, assays, and resistance mechanisms for the development of resistant cultivars.

The research falls under National Program 301, Plant Microbial and Insect Genetic Resources, Genomics, and Genetic Improvement (100 percent), under Action Plan Component 2b Genetic Improvement.

Research allows scientists to select parents and breed disease-resistant strawberries and blueberries through traditional breeding methods and by molecular genetic manipulation, and to study disease causing pests that threaten small-fruit crops. Research provides growers with varieties with reduced pesticide use requirements and reduced cost to the grower. At the same time, varieties will be developed with high phytonutrient contents, such as vitamin C and other antioxidants that are important factors in the human diet. The program works with USDA and State cooperators in Arkansas, Florida, Georgia, Maryland, Michigan, Minnesota, Mississippi, New Jersey, New York, North Carolina, and Oregon.

2.List the milestones (indicators of progress) from your Project Plan.
Year 1 (FY 2004)

Complete crossing for development of anthracnose resistant populations in blueberry.

Complete assay development for RRSV in blueberry.

Complete description of 'funky flower' in cranberry.

Complete germplasm evaluation for anthracnose resistance in strawberry.

Complete fruit quality evaluation of strawberry breeding selections.

Complete bramble frost avoidance studies.

Year 2 (FY 2005)

Complete screening of blueberry seedlings for resistance to mummy berry blight & fruit infection.

Complete evaluation of blueberry seedlings for firmness and horticultural characteristics under field conditions.

Complete AFLP development & begin cloning fragments differentially expressed in mummy infection in blueberry.

Complete strawberry frost avoidance studies.

Complete pallidosis detection method comparison in strawberry.

Complete evaluation of blackberry breeding selections and germplasm collection for sugar, acid, and antioxidant levels.

Year 3 (FY 2006)

Complete primary field evaluations for mummy berry in blueberry.

Complete blueberry germplasm evaluation for fruit quality and antioxidant activity.

Complete determination of blueberry volatiles associated with anthracnose fruit rot.

Select Colletotrichum-resistant strawberry progeny from germplasm enhancement crosses.

Complete Phytophthora fragariae race assignment in strawberry.

Year 4 (FY 2007)

Complete selection in blueberry anthracnose populations. Complete marker development for mummy fruit infection in blueberry. Complete strawberry Botrytis assay studies in strawberry.

Year 5 (FY 2008)

Complete primary field evaluations of disease resistant blueberry genotypes.

Complete evaluations of mechanical harvesting in blueberry selections.

Complete evaluation of wild strawberry germplasm collection for sugar, acid, & antioxidant levels.

Select F1 blackberry progeny.

4a.What was the single most significant accomplishment this past year?
Antioxidant activity in lingonberries and strawberries. Lingonberries and strawberries were shown to possess high antioxidant enzyme and antioxidant activities, and were potent scavengers of DPPH-, ROO-, OH- and O2-free radicals. Small fruits are known to be important potential sources of antioxidants, and enhanced levels of antioxidants in the diet may be beneficial to improved human health. ARS scientists at Beltsville, MD demonstrated that lingonberry and strawberry extracts inhibited the proliferation of human-lung-epithelial-cancer cell-line A549 and decreased TPA-induced neoplastic transformation of JB6 P+ mouse epidermal cells. Lingonberries and strawberries may be highly effective as chemopreventive agents that act by targeting the down-regulation of critical enzyme activities involved in cancer cell proliferation and transformation.

4b.List other significant accomplishments, if any.
Stem blight and Phomopsis twig blight resistance in blueberry. Blueberry cultivars with high resistance to both stem blight and Phomopsis twig blight diseases were identified. These diseases are not readily controlled by normal fungicide applications. ARS scientists at Chatsworth, NJ screened over 50 cultivars under controlled conditions using cut-stem inoculations. This information will allow the development of blueberry cultivars with better disease resistance.

New species of Phytophthora identified. A new species of Phytophthora causing root rot in cranberry was identified. Previous studies with several Phytophthora isolates had produced anomalous results with respect to response to fungicides. ARS scientists at Chatsworth, NJ in collaboration with P.V. Oudemans (Rutgers University), used molecular and morphological studies to identify the new species. This information will allow the improved diagnosis of disease problems in cranberry, and emphasizes the need for recognizing different species when evaluating disease treatments.

Cold hardiness of rabbiteye blueberry cultivars. The cold hardiness of cultivars of rabbiteye blueberry (V. ashei) were measured. When breeding to develop more northern- adapted rabbiteye, or rabbiteye - V. constablaei hybrid selections it is desirable to use the most cold-hardy germplasm as parents. ARS scientists at Beltsville, MD and Chatsworth, NJ evaluated 26 cultivars using a shoot freezing assay, and observed significant differences were among cultivars. This information will allow the development of blueberry varieties that are more cold-hardy and more resistant to damage from late spring frosts.

4d.Progress report.
Resistance to fungal diseases in blueberry. Fungal diseases are serious problems for blueberry growers in most production areas, resulting in crop losses. ARS scientists at Chatsworth, New Jersey continue research on screening both parental material and offspring populations for resistance to mummy berry and anthracnose. New sources of resistance have been identified, and resistant offspring have been selected. Resistant offspring hold the promise of becoming future cultivars after necessary field-testing.

Fruit quality in blueberry. Knowledge of firmness and holding ability is important as the blueberry industry moves toward increased machine harvesting. Seven blueberry cultivars were evaluated for initial firmness, and ability to retain firmness and quality after periods of on-bush holding by ARS scientists at Chatsworth, New Jersey. Initial results have shown differences among the cultivars tested. Knowledge of holding ability will give growers more options in making harvest decisions, and will guide in the development of future cultivars.

Parthenocarpy in blueberry. ARS scientists at Chatsworth, New Jersey continue research aimed at developing parthenocarpic selections in highbush blueberry. Parthenocarpic fruit is seedless fruit that can develop without bee pollination. This trait was previously identified in a breeding selection, and has been incorporated into diverse genetic backgrounds. Initial hybrids and segregating populations are currently under evaluation for expression of this trait. Recovery of this trait in a commercial quality selection may result in both high quality fruit and maximal yields under varying weather conditions since no pollination is needed.

Northern-adapted rabbiteye hybrids. In recent years, V. ashei and V. constablaei derivatives have been generated to provide late-flowering, early-ripening rabbiteye-type hybrids for the southern U.S.; however, this germplasm has also performed well in New Jersey, and could potentially provide northern-adapted rabbiteye types. Rabbiteye has great vigor, and heat adaptation, and V. constablaei has exceptional cold-hardiness. When combined, these germplasms complement each other in many respects. It is expected that with further recombination and hybridization, it will be possible to select hybrids improved for critical commercial characteristics, and to derive selections suitable to locations ranging from the far north to the far south. A study evaluating the effects of Vaccinium constablaei germplasm found that certain blueberry hybrids with 75% rabbiteye and 25% Vaccinium constablaei germplasm were as winter hardy as Vaccinium corymbosum cultivars.

Antioxidant composition of small fruit. ARS scientists at Beltsville, Maryland have analyzed anthocyanin, flavonoids, and phenolic constituents as well as the antioxidant capacity in blueberry, cranberry, wild chokeberry and lingonberry. Cultivars with high antioxidant capacities were identified, and the contribution of individual anthocyanin, flavonoids, or phenolic acids to total antioxidant capacity determined. Information obtained from this research should be useful to breeders in selecting berry cultivars with high antioxidant content and to consumers concerned with the health benefits of small fruit.

Lingonberry germplasm. Lingonberry and lingonberry-cranberry hybrids were evaluated for survival under New Jersey conditions, and for basic morphological characteristics. The strongest clones were selected and moved to an advanced trial.

5.Describe the major accomplishments over the life of the project, including their predicted or actual impact.
Two albino blueberry selections were released, as germplasm, in response to requests from the nursery industry. These selections address needs of the small-fruit industry and help the industry in the United States remain profitable. Not listed as a specific CRIS milestone, National Program 301, Component 2b: Genetic Improvement, ARS Strategic Plan Performance Measure, 1.2.8.

Foliar resistance to anthracnose in blueberry was evaluated via a leaf disk assay. Significant differences were observed among cultivars, but the results were not correlated to anthracnose fruit-rot resistance. Several cultivars were identified with good resistance to both foliar and fruit infection. Foliar resistance offers opportunities for breeding for lowered survival of over-wintering disease inoculum, and may help growers manage this disease under field conditions. This research addresses 2004 Milestone - Complete crossing for development of anthracnose resistant populations in blueberry, National Program 301, Component 2b: Genetic Improvement, ARS Strategic Plan Performance Measures, 3.2.4, 3.2.5.

The cold hardiness of various blueberry germplasm types was evaluated, and types with exceptional cold hardiness were identified. This information will assist in breeding for cultivars with better resistance to extreme winter temperatures and better resistance to damage from late spring frosts. This research addresses 2005 Milestone - Complete evaluation of blueberry seedlings for firmness and horticultural characteristics under field conditions, National Program 301, Component 2b: Genetic Improvement, ARS Strategic Plan Performance Measure, 1.2.5.

One hundred blueberry cultivars have been screened for resistance to anthracnose fruit rot. No absolute resistance to anthracnose has been found, but the strongest sources of resistance have been utilized in the breeding program. Field screening for resistance has resulted in numerous disease resistant selections being made. This research addresses 2004 Milestone - Complete crossing for development of anthracnose resistant populations in blueberry, National Program 301, Component 2b: Genetic Improvement, ARS Strategic Plan Performance Measures, 3.2.4, 3.2.5.

Numerous genotypes of blueberry, strawberry, and other small fruit have been screened for antioxidant capacity and those with high levels have been identified. This information is being utilized in the development of selections and cultivars with enhanced antioxidant levels. This research addresses 2006 Milestone - Complete blueberry germplasm evaluation for fruit quality and antioxidant activity, National Program 301, Component 2b: Genetic Improvement, ARS Strategic Plan Performance Measure, 4.1.2.

6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products?
Strawberry Field Day (Beltsville, MD) was held for growers and extension personnel.

Two albino blueberry selections were released in response to requests from the nursery industry.

Blueberry seedlings have been transferred yearly to breeding program cooperators at the USDA-ARS Small Fruit Research Center in Corvallis, Oregon, the University of Georgia, and the University of Arkansas. Advanced selections are transferred yearly to USDA cooperators in Oregon, and State cooperators in New Jersey, Arkansas, Georgia, Michigan, and Minnesota. Cuttings of newer released cultivars are distributed to growers at Blueberry Field Days to encourage growers to evaluate new materials. The timeframe for availability of new cultivars to end-users is dependent upon the amount of testing necessary to assure performance superior to current standards. Five to six years of testing advanced selections is typical, and new selections are under continuous development.

7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below).
Polashock, J.J. 2004. 'Molecular identification of the 'Black Shadow' fungus from blueberry' (poster) MAPMBS meeting, August 13, 2004, Laurel, MD

Polashock, J.J. 2004. 'DNA fingerprinting and disease resistance in cranberry'. American Cranberry Grower's Association annual meeting, August 19, 2004, Mount Holly, NJ.

Ehlenfeldt, M.K., Polashock, J.J. 2004. Program overview presentations to the U.S. Highbush Blueberry Council, September 29, 2004, Chatsworth, NJ.

Ehlenfeldt, M.K., Lewers, K.S. 2004. Strawberry and blueberry presentations at the NCR-22 Small Fruit Research Committee Meetings, October 20-22, 2004,Indianapolis, IN.

Ehlenfeldt, M.K. 2005. 'Winter-hardiness and deacclimation behavior of diverse blueberry (Vaccinium spp.) genotypes under field conditions'. Vegetable Growers Association of New Jersey annual meetings, January 13, 2005, Atlantic City, NJ.

Polashock, J.J. 2005. 'The potential use of volatile analysis as a marker for disease resistance to stem blight and Phomopsis in blueberry'. Vegetable Growers Association of New Jersey annual meetings, January 13, 2005, Atlantic City, NJ. Polashock, J.J. 2005. 'Marker Assisted Selection for fruit rot resistance in cranberry'. American Cranberry Grower's Association annual meeting, January 27, 2005, Mount Holly, NJ.

Ehlenfeldt, M.K. 2005.'USDA-ARS breeding program update'. New Jersey Blueberry Growers Association annual meetings, March 1, 2005, Hammonton, NJ.

Polashock, J.J. 2005. 'Evaluations of anthracnose resistance via leaf disk assays in blueberry and evaluations of resistance to other diseases'. New Jersey Blueberry Growers Association annual meetings, March 1, 2005, Hammonton, NJ.

Turechek, W. 2005. The practical considerations of scale in plant pathology (abstract). Proceedings of the 9th International Workshop on Plant Disease Epidemiology, April 11-15th, 2005, Landerneau, France, pp 47.

Presentations and displays at BARC Field Day, June 4, 2005, Beltsville, MD.

Review Publications
Ayala-Zavala, J.F., Wang, S.Y., Wang, C.Y., Gonzalez-Aguilar, G., Montoya, L.C. 2004. Effect of storage temperatures on antioxidant capacity and aroma compounds in strawberry fruit. Swiss Society of Food Science and Technology. 37:687-695.