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ARS Home » Pacific West Area » Hilo, Hawaii » Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center » Tropical Plant Genetic Resources and Disease Research » Research » Research Project #414338

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

Location: Tropical Plant Genetic Resources and Disease Research

2009 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. Formerly 5320-21000-009-00D (6/08).

3. Progress Report
Scientists from Hilo, Miami & Puerto Rico established contacts with Guangxi Subtropical Crops Research Institute (SCRI) & South West Forestry University in China (5/2009). Identified and collected plant germplasm from U.S. domestic sources including Lansium domesticum from private orchards in Hawaii. A new research project with ohelo berry as a new crop from Hawaii was initiated and is progressing. Provided daily care to 14 designated tropical fruit & nut crops at the Hilo site for 1000 accessions in 33 field acres, greenhouses, tissue culture & seed storage. Regeneration of traditional papaya germplasm collection in a location with papaya ringspot virus pressure. Transgenic PRSV resistant papaya plants have the potential as a trap crop to protect PRSV susceptible Caricaceae and is proving to be successful. On-farm testing of pre-harvest disease management impact on post- harvest fruit quality was conducted. Data for field analysis of guava host resistance to Pestalotiopsis (scabby canker disease) and fruit flies was compiled to evaluate the susceptibility of guava genotypes to pest and pathogen attack under natural field conditions. Thai cultivars appear to be more susceptible to Pestaliotiopsis and ‘Red Indian’ was most susceptible to fruit fly infestation. Based on our developed scale, host resistance to fruit flies and scabby canker may not be interrelated. A chemical management procedure for Macadamia Quick Decline disease is completed. Diseases of unknown etiology effecting field management and fruit quality were determined for rambutan. Crop management method for ‘Kaimana’ resulted in consistent production over the past 3 years in Hilo. Further testing at cooperator locations in Hilo (1),Hamakua & Kona(1).

4. Accomplishments
1. Strategically expand and improve collections. Expansion of collections is hindered by the need of established cooperative agreements between countries at higher administrative levels. ARS scientists in Hilo, HI established excellent initial contacts in China, and a draft of a Non Funded Cooperative Agreement (NFCA) is being prepared to further cooperation between the USDA/ARS, NPGS with the Subtropical Crop Research Institute in Guangxi and the South West Forestry University in Yunnan, China for plant germplasm and technology exchanges. This will establish official exchange relationships with China’s plant germplasm institutes and strategically expand and improve collections.

2. Efficiently & effectively conserve and distribute tropical fruit genetic resources. Genetic resources are the foundation of our agricultural future, and their conservation, safety health and genetic integrity must be maintained. ARS scientists at Hilo, HI organized, applied for and were awarded a three year research grant through the CSREES Specialty Crop Research Initiative for “Ohelo berry, a specialty value added and ornamental crop from Hawaii”. A cooperative project was established between the USDA/ARS, NPGS Hilo & Corvallis repositories, the University of Hawaii, Cooperative Extension Services, and private industries including the Big Island Nurseryman’s’ Association, North American Plant LLT, Oregon State University, the Kona Chefs group and Big Island Candies, Ltd. The project deals with the sustainable utilization and conservation of an endemic plant germplasm. This research will help efforts to develop a new economic crop for small farms in Hawaii and Oregon.

3. Germplasm conservation and distribution. Proper conservation and distribution of tropical and subtropical fruit and nut genetic resources are critical for continued progress in plant breeding and genomics research by national and international scientists. ARS scientists and technicians at the National Clonal Germplasm Repository in Hilo, Hawaii provided daily maintenance and care for a collection of over 1000 accessions of 14 tropical fruit and nut crops in 31 acres of living field, greenhouse, and tissue culture. During fiscal year 2009, 41 germplasm orders were distributed, 61 new samples were introduced, and more than 10,000 observation and data records were loaded into the Germplasm Resources Information Network (GRIN). This research provides efficient and economical methods for the management, preservation, and distribution of these valuable plant genetic resources for future conservation and crop improvement strategies.

4. Determine the effect of environmental and crop management on timing and uniformity of flowering for lychee. Cultural management practices that synchronize vegetative growth and promote uniform maturation of shoot terminals prior to floral induction conditions are needed to increase the reliability of flower and fruit descriptor data. The pruning and fertilizer management method developed by ARS scientists at Hilo, HI for “Kaimana” lychee has proven successful at the USDA/ ARS station in Puerto Rico. The improved descriptors data will be entered in the Germplasm Resource Information Network. This data will enhance the reliability of lychee fruit harvest and improve the crops value.

5. Detecting transgenic presence in seeds. There is, at present, no way to tell if transgenic material is present in papaya seeds. ARS scientists at Hilo, HI have submitted a manuscript describing a developed protocol utilizing polymerase chain reaction (PCR) for the detection of transgenic material in both the parental plants and the resulting seed population. The protocol will test each plant for the 55-1 transformation event to assure a 99.9% chance of obtaining greater than 99.5% transgene-free seeds. This procedure should ensure the purity of the traditional papaya cultivars from contamination of the transgenic line.

6. Expansion of pineapple collection. One of Hawaii’s largest collections of pineapple may not be further maintained by the industry. Fifty-two accessions from that collection were added by ARS scientists at Hilo, HI to the repository. These materials are currently being quarantined and initiated into tissue culture. With the new accessions, the repository’s collection of pineapple will number 236 accessions, material that will be used for disease resistance, breeding programs, and flowering studies.

7. Pre-harvest disease management. There is a need to detect, characterize and document fungal pathogens that could impede the distribution of disease-free rambutan germplasm. A disease of unknown cause that is affecting field management and fruit quality of rambutan was determined by ARS scientists in Hilo, HI and varietal differences among 9 cultivars were documented, identifying sources of host resistance. This research, which was the foundation for a new National Pest Advisory Group (NPAG) Report, will be used by the Hawaii Department of Agriculture and the Animal Plant Health Inspection Services to regulate movement of plant pests. This work will also be used by growers to make variety and management choices.

Review Publications
Keith, L.M. 2008. First report of Pestalotiopsis virgatula on rambutan in Hawaii. Plant Disease 92(5):835.