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Research Project: Improving the Quality of Grapes, Other Fruits, and their Products through Agricultural Management


2014 Annual Report

Objective 1: Identify, develop, and define analysis techniques to evaluate primary and secondary metabolites of fruit, fruit products, and wine. [NP 305; C1, PS1B] Sub-objective 1.A. Determine quality indicator metabolites and analytical methods for their analysis; evaluate and optimize new methods where insufficient data exists. Sub-objective 1.B. Deploy quality component measurements to optimize agricultural practices targeted at improving product quality. Objective 2: Integrate canopy- and fruit-specific management practices in grapes and berries to enhance crop productivity and fruit quality. [NP 305; C1, PS1B] Sub-objective 2.A. Determine development of fruit quality parameters as driven by the interaction between temperature and the timing of temperature anomalies during critical periods of fruit development. Sub-objective 2.B. Quantify standard industry pruning methods for grapevines and develop formal pruning standards necessary to achieve targeted goals for canopy structure; evaluate efficacy of manual pruning and algorithm-driven mechanical systems to achieve canopy structure goals. Sub-objective 2.C. Define canopy and fruit temperature thresholds leading to reduced fruit marketability in drip-irrigated blueberry fields. Objective 3: Develop cultural management strategies that mitigate the impact of abiotic stresses (drought and cold) in winegrapes. [NP 305; C1, PS1B] Sub-objective 3.A. Determine how irrigation spatial delivery, frequency, and amount affect the photosynthesis, water use efficiency, crop load and berry maturity of winegrapes. Sub-objective 3.B. Determine the influence of seasonal water deficit on cold acclimation during bud dormancy in winegrapes.

Project objectives will be accomplished by integrating research across three core disciplines: food chemistry- phytochemical analysis, plant-microclimate interactions, and crop physiology. A systematic approach in targeted fruit quality compound analysis to predict the magnitude by which climate and cultural factors impact fruit quality components will be used. This approach will allow is to improve and define analytical methods for plant metabolite analysis that advance our comprehension of the relationships among canopy management, canopy microclimate, water management, and vine cold hardiness and their effects on fruit development, fruit quality components, and vine physiology. If weather interferes with experimental treatments and sampling, experiments will be adjusted and extended an additional growing season.

Progress Report
This report documents progress for this new project which began in November of 2013 and continues research from 5358-21000-041-00D, "Vineyard Management Practices and the Quality of Grapes and Grape Products in the Pacific Northwest". Please see the report for the previous project for additional information. We have continued to research how agricultural management practices improve fruit and fruit product quality. One review article was published summarizing our past 5 years of findings. Additional sample preparation and metabolite analysis methods were evaluated and published. Some of these methods were employed to clarify the confusion surrounding Rubus coreanus Miq. (bokbunja; Korean black raspberry) and Rubus occidentalis L. (American black raspberry) pigment composition. Following interviews with growers representing one-third of the wine-grape acreage in Washington State, consensus rules for spur-pruning cordon-trained vines, or "grower best practices" were established and formalized. These "rules" were applied to experimental vines and outcomes compared with the application of the best practices by growers' pruning crew members. Two studies were established, representing disparate growing regions, vine architecture, and cultivars. Indicators of canopy architecture and indicators of fruit quality were measured. An objective of our former project was to enhance understanding of how irrigation practices (amount and frequency) influence wine grape productivity and berry maturity. We continued this research during this first year of the new project by completing a third year of irrigation treatment application and data collection. Optimizing productivity of irrigation water used in wine grape production is critical in arid climates, yet precision irrigation decision-making is hindered by the lack of an automated method for monitoring vine water status. We collected the first season of data for using a neural network to predict well-watered leaf surface temperature, as well as calculate and interpret a crop water stress index for irrigation scheduling. As part of our new project objective to determine the influence of prior drought stress on subsequent bud cold hardiness in wine grapes, we conducted preliminary experiments to parameterize temperature doses for inducing changes in bud cold hardiness and used differential thermal analysis to quantify low temperature exotherm initiation temperatures. Seasonal changes in bud cold hardiness for various cultivars of wine grape were monitored and related to winter weather events.

1. What’s really in your black raspberry supplements? Controls are needed to ensure that dietary supplements already in the marketplace meet a certain minimum quality, and that they contain their labeled contents (i.e., black raspberry supplements contain a minimum anthocyanin concentration). All available black raspberry products marketed as supplements were purchased for this work. Each was analyzed for authenticity and anthocyanin concentration by an ARS researcher at the Parma, Idaho, worksite. Seven out of nineteen samples did not contain any black raspberry fruit, and three out of those seven had no detectable anthocyanin. Food sources remain a safer method of obtaining dietary phenolics than dietary supplements.

2. Bokbunja fruit pigment fingerprinting. Korean black raspberries (bokbunja; Rubus coreanus Miq.) are loaded with red, purple to black pigments. While native to East Asia, commercial bokbunja planting has been increasing with the demand for bokbunja functional foods. Though most Korean black raspberry growers are unknowingly growing Rubus occidentalis L. (not bokbunja, but actually Western and Eastern North American black raspberries). ARS researchers in Parma, Idaho and Corvallis, Oregon, in collaboration with a Canadian collaborator, demonstrated that the pigment fingerprint is unique for each of two species, and can be used for taxonomy criteria and authenticity work.

3. Chicoric acid widely available. ARS scientists in Parma, Idaho, and Corvallis, Oregon, reported on chicoric acid identification, potential health benefits, plant distribution and effects of processing. Dietary supplements containing chicoric acid (i.e., dandelion extract) have increased in popularity after being featured on a U.S. television program. Though that reportage only mentioned dandelion and basil as dietary sources of chicoric acid, fortunately it is much more widely available than the show made it appear. Chicoric acid has been identified in over 60 genera and species: from plants as diverse seagrass, fern frond, basil, and lettuce.

4. Grow tubes influence blueberry bush architecture. Growth tubes are used to accelerate growth in new plantings of perennial crops by reducing light, and increasing humidity and temperature. An ARS scientist in Prosser, Washington, with scientists at Oregon State University, studied the impact of growth tubes on blueberry establishment. There was no effect on root or crown growth despite changes in the temperature of the soil surface. Previously unknown, the total amount of leaf tissue was less inside the tubes than on plants without tubes, until the plants grew above the top of the tube. At the end of the season, the plants with tubes were more upright, which may be an advantage during machine harvesting, as more fruit will be caught by the harvester.

5. Grapevine yield estimation can be automated. It is important to estimate yield in vineyards to allow for contract negotiation, harvest logistics, and marketing projections. An ARS scientist at the Prosser, Washington, worksite developed a trellis tension monitoring system that can be used to estimate crop yields that is as good as or better than the current labor-intensive method used for estimating yield. This system monitors the tension in the trellis wire as the fruit increases in size. Fruit yields can be estimated before veraison to within 20% of actual yields. This information is being used in the juice grape industry and evaluated in wine grapes to optimize processing capacity and predict labor needs.

Review Publications
Tarara, J.M., Chaves, B., Strik, B.C. 2014. Grow tubes change microclimate and bush architecture but have little effect on bush biomass allocation at the end of the establishment year in blueberry. HortScience. 49:596-602.
Strik, B.C., Buller, G., Tarara, J.M. 2014. Grow tubes reduce root and crown growth but not early production during establishment of highbush blueberry. HortScience. 49:581-588.
Lee, J. 2014. Marketplace analysis demonstrates quality control standards needed for black raspberry dietary supplements. Plant Foods for Human Nutrition. 69:161-167.
Shellie, K., Cragin, J.J., Serpe, M.D. 2014. Lesser-known European wine grape cultivars in southwestern Idaho: cold hardiness, berry maturity and yield. HortTechnology. 24:138-147.
Shellie, K. 2014. Water productivity, yield, and berry composition in sustained versus regulated deficit irrigation of Merlot grapevines. American Journal of Enology and Viticulture. 65:197-205.
Shellie, K., Bowen, P. 2014. Isohydrodynamic behavior in deficit-irrigated Cabernet Sauvignon and Malbec and its relationship between yield and berry composition. Irrigation Science. 32:87-97.
Lee, J. 2014. Establishing a case for improved food phenolic analysis. Food Science and Nutrition. 2:1-8.
Lee, J., Scagel, C.F. 2013. Chicoric acid: chemistry, distribution, and production. Frontiers in Chemistry. 1:40.
Lee, J., Dossett, M., Finn, C.E. 2013. Anthocyanin fingerprinting of true bokbunja (Rubus coreanus Miq.) fruit. Journal of Functional Foods. 5:1985-1990.