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


2016 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 us 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
During the past year, we have continued to research how management of agricultural practices can advance fruit and fruit product quality. We developed, verified, and applied analytical methods, while also utilizing existing metabolite information (from verified authentic fruit sources on new cultivar releases) to improve current food/dietary supplement quality control and safety issues (i.e., fruit based dietary supplements). We established methods in support of industry stakeholders that advocate high-quality dietary supplements and seek a quality assurance technique to authenticate ingredients used in their products. We demonstrated that anthocyanin (pigment) profiling by High Pressure Liquid Chromatography (HPLC), as commonly used in quality control of food ingredients, could be especially useful to dietary supplement production. As part of the project objective to develop cultural management strategies that mitigate the impact of abiotic stresses (drought and cold) in wine grapes, another growing season of irrigation treatment application is in progress and cold hardiness/injury was evaluated winter 2015-16 and spring 2016. In autumn 2015, fruit from the 2015 growing season were analyzed for yield components and berry maturity. During winter 2015-16, differential thermal analysis was used to quantify the bud and cane cold hardiness of vines in irrigation field trial plots that had been deficit-irrigated during the 2015 growing season. In spring of 2016, wine grape cultivars in irrigation field trial plots were visually rated for severity of cold injury. During the 2016 growing season, irrigation treatment applications began after fruit set in June. Vines are being supplied with either 70% or 35% of their estimated water demand. All irrigation amounts are delivered as a single weekly irrigation event or apportioned into thirds and delivered as three irrigation events per week. Field instrumentation and a wireless interface were installed in June and July and data are being used to calculate a daily water stress index. Measurement of weekly midday leaf water potential began in June.

1. Adulteration detection in dietary supplements. Current fruit-based dietary supplements in the U.S. marketplace have no obligation to meet any fruit-component concentration requirement. For example, berry supplements might be promoted for their high anthocyanin content, but they actually have no standard or minimum anthocyanin threshold for legal sale. An ARS scientist in Parma, Idaho, used anthocyanin profiles to characterize currently available fruit-based dietary supplements. Over 25% of the fruit based dietary supplements evaluated contained no detectable anthocyanins, or had unlabeled anthocyanins despite packaging labels promising specific sources of anthocyanins. Anthocyanin profiling by HPLC can still be used in dietary supplement quality assurance, but systems to improve fruit based dietary supplements’ quality are needed from source material to final products.

2. Foliar application of a plant hormone increases grapevine cold hardiness. Wine grapevines of European origin (Vitis vinifera) are often injured or killed by cold weather events in autumn, mid-winter and spring. An ARS scientist in Parma, Idaho, in cooperation with Canadian collaborators and collaborators at Washington and Ohio State Universities, identified concentrations, application timings and formulations of abscisic acid that increased bud cold hardiness by up to 4°C in the wine grape cultivars Chardonnay and Merlot. Foliar application of a naturally occurring form of abscisic acid advanced the onset of dormancy and increased bud cold hardiness in autumn. Foliar application of a purported long-lived analogue of abscisic acid (8’-acetylene abscisic acid) increased bud cold hardiness and delayed bud break in the spring following application and was most effective when applied after harvest. These findings provide cultural practices that wine grape producers can use to mitigate the risk of economic loss due to cold injury.


Review Publications
Tarara, J.M., Perez-Peña, J.E. 2015. Moderate water stress from regulated deficit irrigation decreases transpiration similarly to net carbon exchange in grapevine canopies. Journal of the American Society for Horticultural Science. 140:413-426.
Lee, J. 2016. Further research on the biological activities and the safety of raspberry ketone are needed. NFS Journal. 2:15-18.
Lee, J. 2016. Rosaceae products: Anthocyanin quality and comparisons between dietary supplements and foods. NFS Journal. 4:1-8. doi: 10.1016/j.nfs.2016.04.001.
Finn, C.E., Strik, B.C., Yorgey, B.M., Mackey, T.A., Hancock, J.F., Lee, J., Martin, R.R. 2016. ‘Baby Blues’ highbush blueberry. HortScience. 51(6):761-765.
King, B.A., Shellie, K. 2016. Evaluation of neural network modeling to predict non-water-stressed leaf temperature in wine grape for calculation of crop water stress index. Agricultural Water Management. 167:38-52.
Bowen, P., Shellie, K., Mills, L., Willwerth, J., Bogdanoff, C., Keller, M. 2016. Abscisic acid form, concentration, and application timing influence phenology and bud cold hardiness in Merlot grapevines. Canadian Journal of Plant Science. 96:347-359. doi: 10.1139/cjps-2015-0257.