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United States Department of Agriculture

Agricultural Research Service

Research Project: Pacific Fruit Genetic Resource Management and Sustainable Production Systems

Location: Tropical Plant Genetic Resources and Disease Research

2012 Annual Report


1a.Objectives (from AD-416):
Collect, maintain, evaluate and distribute germplasm of 14 designated tropical fruit and nut crops. (1) Strategically expand and improve collections of priority tropical fruit genetic resources and associated information. (2) Efficiently and effectively conserve and regenerate tropical fruit genetic resources and distribute disease-free samples and associated information woldwide. (3) Characterize and evaluate tropical fruit genetic resources for priority traits, such as biotic and abiotic stress resistance, quality factors, and other horticultural properties.


1b.Approach (from AD-416):
(1) Extend and strengthen research collaboration with plant genetic resource institutes in Southeast Asia to jointly collect and preserve priority landrace population of Litchi and Nephelium. Identify and establish contacts in Central America to collect Carica and Vasconcellea germplasm. Survey existing U.S. domestic collections of tropical fruit genetic resources to identify material that would fill gaps in NPGS collection, acquiring and characterizing them. (2) Maintenance and research on 14 designated crops in field plantings, tissue culture and seed storage and regeneration. Optimize regeneration and long-term low temperature storage procedures for Carica, Vasconcellea, Macadamia and Canarium seeds. Develop and implement the means for effectively managing PRSV disease in gene bank plantings of Carica and Vasconcellea. Utilize transgenic PRSV resistant papaya as border plantings to facilitate the regeneration of tradional non-transgenic papaya germplasm in PRSV infected area. Detect, characterize and document fungal pathogens which could impede the distribution of disease free rambutan and longan germplasm. (3) Morphologically characterize, evaluate, and document the horticultural qualities of priority tropical fruit crops. Incorporate evaluation and characterization data into the ARS Germplasm Resources Information Network (GRIN). Develop rapid and accuate diagnostic assays for evaluating the susceptibility of rambutan and longan to fungal diseases. Determine the effect of environment and crop management on timing and uniformity of flowering for litchi, longan, and rambutan to improve descriptor data collection and to enhance their commercial appeal as crops.


3.Progress Report:
Initiated and maintaining a backup collection of selected cacao accessions from Miami and Puerto Rico. Continue quarantine secured transfer of the National avocado collection from Miami to Hilo to protect the collection from the laurel wilt disease. The 23 accessions of avocado received in July 2010 were tested free of Avocado Sunblotch viroid (ASBv) and laurel wilt at Miami and Fort Detrick before transferring to Hilo. The unit plant pathologist will provide a routine screening for Avocado Sunblotch Viroid (ASBv) and laurel wilt using available test kits. Seeds of 2 accessions of Myrica rubra (860 counts) were received from Yunnan, China, in March, and nine Vasconcellea accessions from Germany in May. These activities support objective 1 to expand and improve collections. Observations are being collected from pineapple, rambutan, Canarium, Carica and Psidium flowers and fruits. This supports objective 3 characterization and evaluation of genetic resources. Supporting objective 2, to efficiently and effectively conserve and regenerate genetic resources the unit has kept the Vasconcellea collections maintained as pot culture in an enclosed screened house to protect from the Papaya Ringspot Virus (PRSV) disease. The same approach will be implemented for the avocado backup collection. Current tropical fruit tree plantings over 25 years old are being propagated for replanting on their own roots (by air layering and cuttings). This will minimize risk of rootstock overgrowth in the field. A pig exclusion fence is completed for the breadfruit collection. The “Specialty Crop Research Initiative” (SCRI) funded ohelo project is completed as the stated objectives were accomplished ahead of schedule. Objectives include release of three ornamental/fruit varieties; streamlined in vitro commercial propagation to provide the germplasm to interested growers; establish molecular fingerprinting for identification, and establish procedures for cryogenic storage; identify important pathogens and environmental factors that affect production and qualities of ohelo in sustainable culture; conduct cost and feasibility analysis of ornamental production, and publish culture and production management methods in extension bulletins. For routine germplasm maintenance and care, the curator and five FTE field/laboratory staff provide efficient management of thirty-three acres of living collections at four locations and a backup in vitro collection in the laboratory. The amount of plant germplasm distributed this past year was 57 orders for 256 items. This supports our Objective 2 to distribute samples and associated information.


4.Accomplishments
1. Improved targeted germplasm through exchanges nationally and internationally. Exchange genetic resources with cooperators in research institutes in China, Germany and US. Provide germplasm for evaluations, conservations and improve diversity. Provide Garcinia seeds to Yunnan China in exchange for the introduction of Myrica rubra seeds; provide Vasconcellea tissue samples to University of Illinois for characterization and genetic research; received 9 accessions of Vasconcellea germplasm as new germplasm from Germany to improve the NPGS collection in Hilo. Acquired, characterized and preserved important germplasm for scientific and educational purposes.

2. Provide backup to safeguard germplasm from diseases and natural disasters. The highest priority for the ARS genebanks is to conserve genetic resources. The Hilo site serves as a backup location for Miami and Puerto Rico for selected cacao, avocado, and litchi germplasm. To date 26 avocado and 30 cacao accessions have successfully been transferred to this repository. These collections are vital to domestic and international food security now and in the future.

3. Provide daily maintenance of 14 designated tropical fruit crops and provide available germplasm for research and evaluation. Provide best horticultural care and management daily for 14 designated crops in 31 acres in field, greenhouse and in tissue culture; provide small amount of available germplasm free of charge for research and education. Efficient and effective management of germplasm to ensure long-term integrity, health, and availability of germplasm for research. Three field locations at 600 feet, 4,000 feet and 250 feet elevation to provide the most suitable growing conditions for selected crops, accessions older than 20 years are regenerated on own roost to ensure no stock over grown in long term planting. Transfer of avocado germplasm begin in 2011 and will continue for the next 5 years. Continue improvement on management methods; fulfill germplasm needs in research and education; conservation and safeguard the national plant germplasm collection.

4. Provide economical and environmental impact through sustainable management of germplasm. Sustainability of genetic resources is an on-going problem. From about one quart of berries of Ohelo berry, Vaccinium reticulatum, we demonstrated the sustainable culture and production of this native berry for fruit and ornamental potted plants. The impacts include a potential new economic crop for value added products and reduction of demand for wild harvesting of berries. The project released three varieties, established a highly diverse domesticated seed source, and demonstrated success in propagation and potted plant productions.


Review Publications
Hummer, K.E., Pomper, K., Postman, J.D., Graham, C.J., Stover, E.W., Mercure, E.W., Aradhya, M.K., Crisosto, C.H., Ferguson, L., Thompson, M., Byers, P., Zee, F.T. 2012. Emerging fruit crops. Book Chapter. p. 97-147.

Reed, B.M., Uchendu, E., Wada, S., Zee, F.T. 2012. Alternative storage for germplasm of native hawaiian berries. Acta Horticulturae. 918:113-120.

Van Buren, R., J. Li, F. Zee, J. Zhu, C. Liu, A.K Arumuganathan, R. Ming. 2011. Longli is not a hybrid of longan and lychee as revealed by genome size analysis and trichome morphology. Tropical Plant Biology. 4:228-236.

Ummarat, N., T.K. Matsumoto, M.M. Wall, K. Seraypheap. 2011. Changes in antioxidant and fruit quality in hot water-treated ‘Hom Thong’ banana fruit during storage. Sci Hort. 130:801-807.

Last Modified: 10/1/2014
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