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United States Department of Agriculture

Agricultural Research Service

Research Project: PHYSIOLOGICAL AND GENETIC BASIS OF POSTHARVEST QUALITY AND PHYTONUTRIENT CONTENT OF FRUITS AND VEGETABLES
2009 Annual Report


1a.Objectives (from AD-416)
The overall objective of this project is to develop value-added products from fruits and vegetables, especially those containing phytonutrients. Anthocyanins and carotenoids are plant pigments that contribute to fruit quality and are also phytonutrients, and will be one objective of this project. Other objectives include selection and breeding of watermelon for enhanced lycopene content and modification of fruit quality for new market niches.


1b.Approach (from AD-416)
Experiments to determine the physiology and develop technology necessary to extend the shelf life, marketability, and phytonutrient content of highly perishable fruits will be conducted. Enhancement of watermelon germplasm for market traits will be done using classical breeding techniques and exploration of the carotenoid path in watermelon will be done using molecular methodology. Food-grade formulations for extraction and stabilization of aqueous-based lycopene for extended shelf will be developed.


3.Progress Report
Work under this project, ending in June 2009, addressed phytonutrient research. Primocane fruiting blackberries selections were evaluated for firmness, shelf life, and composition in cooperation with the University of Arkansas. Selections that were sweet and with good shelf life were found. Documentation of blackberry sweetness was used in marketing and resulted in increased acreages of high-value varieties in three states. A postharvest method was developed that reduced fruit decay from ripe rot by 10 to 20%. In cooperation with the University of Arkansas, Oregon State University, and Cornell University, total phenolic and anthocyanin contents in raspberry were analyzed to determine effects of production and genetics on antioxidant content. This information will help in developing a functional food market for raspberries. It was demonstrated that watermelon lycopene is stored as a chiral arrangement inside a membrane to form chromoplasts. This is important to know so that lycopene enrichment for food use is economic, and a simple and reliable technique was developed that does not use organic solvents to isolate and stabilize certain carotenoids. These technologies can lead to development of value-added products from cucurbits. Low-sugar watermelons were developed using classical breeding methods and were shown to be acceptable for flavor and texture and will benefit consumers who need to follow a low-sugar diet. It was found that citrulline, an amino acid associated with improved blood circulation and with prevention of cancer and heart disease, is available from watermelon juice. In cooperation with researchers at Texas A&M the effectiveness of watermelon in ameliorating cardiovascular events in Zucker diabetic fatty rats was determined. Rats fed watermelon or arginine/citrulline had reduced blood glucose and weight gain, and better aortic flexibility. Amino acids in watermelon have promise in controlling obesity in humans, and the pomace may be useful for value-added products. It was demonstrated that watermelon contains more lycopene than tomatoes. This information was used by a commodity board to gain an approved statement for marketing. Studies determined which varieties and storage and production methods (including grafting) yielded the highest carotenoid contents in watermelon. This information will help growers select varieties known to be high in lycopene, and aid breeders interested in developing new high pigment watermelons. This information may be useful in determining effective strategies for increasing natural lycopene content in fruit. The carotenoid pathway of watermelon was determined. Additional research with international and multi-state cooperators determined that molecular markers could be utilized to speed up selection for watermelon with a high lycopene trait. The overall impact from this project has been in improved technologies for developing functional foods and establishment of the health value of specific fruits and vegetables.


4.Accomplishments
1. Carotenoid pathway genes in watermelon: Watermelons contain carotenoids, pigments with antioxidant properties. Scientists at the South Central Agricultural Research Laboratory in Lane, OK, in cooperation with researchers at Texas A&M, USDA-ARS Charleston, NC, and the Newe Ya'ar Research Center, ARO, Israel, determined that a point mutation in the Lycopene beta-cyclase gene inhibits downstream production of carotenoids which causes accumulation of lycopene and thus produces red watermelon. The experiment also determined that the functional version of this gene produces yellow varieties. The scientists cloned this gene and produced a molecular marker. This tool can be used to select breeding plants at the seedling stage for red or yellow fruit color. Since red watermelon contain more carotenoids then yellow watermelons, this marker can also be used to select for increased nutrition in watermelon.

2. Inheritance of four watermelon flesh colors: Watermelon come in many different colors and color combinations but the inheritance of flesh color has been difficult to study because of the subjective nature of visual ratings. Scientists at the South Central Agricultural Research Laboratory in Lane, OK, in cooperation with researchers at Texas A&M, used visual ratings in conjunction with specialized methods and equipment to study the inheritance of color at the molecular as well as biochemical level. One new color type (pale) and multiple new pigments were determined (carotenoids and chlorophylls) as well as how these traits were inherited. This knowledge will allow improved breeding practices for watermelon selection and may lead to improved phytonutrient content of watermelon.


5.Significant Activities that Support Special Target Populations
1. Scientists participated in extension tours, field days, and agricultural conferences where technology was transferred to primarily small-acreage growers.

2. Scientists actively interacted with local, female, small-scale organic growers to help with marketing and production issues in fruit and vegetable production.


6.Technology Transfer

Number of the New/Active MTAs (providing only)1
Number of Invention Disclosures Submitted1
Number of Web Sites Managed1

Review Publications
Takeda, F., Perkins Veazie, P.M. 2009. The Nuts and Bolts of High Tunnel production and Manipulation for Specialized Applications: Introduction to the Workshop. HortScience. 44(2):230.

Moore, P., Perkins Veazie, P.M., Weber, C., Howard, L. 2008. Environmental effect on antioxidant content of ten raspberry cultivars. Acta Horticulturae. 777:499-503.

Weber, C.A., Perkins Veazie, P.M., Moore, P., Howard, L. 2008. Variability of antioxidant content in raspberry germplasm. Acta Horticulturae. 777:493-498.

Levi, A., Wechter, W.P., Davis, A.R. 2009. EST-PCR Markers Representing Watermelon Fruit Genes are Polymorphic among Watermelon Heirloom Cultivars Sharing a Narrow Genetic Base. Plant Genetic Resources. 7:16-32.

Last Modified: 4/18/2014
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