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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 #424486

Research Project: Pacific Tropical/Subtropical Fruit and Nut Genetic Resource Management and Sustainable Production Systems

Location: Tropical Plant Genetic Resources and Disease Research

2014 Annual Report

Objectives of this research project are:(1) Efficiently and effectively conserve, backup, regenerate and evaluate tropical/subtropical fruit and nut genetic resources and distribute samples and associated information worldwide; (2) Strategically expand and improve current tropical/subtropical fruit and nut germplasm collections through international exchanges; (3) Strengthen the genebank’s genetic marker analytical capacity to minimize inefficiencies in sample handling and to contribute more extensively to the multi-site NPGS tropical/subtropical crop genetic characterization program; and (4) Develop a “quarantine-safe” germplasm transfer system modeled after the ongoing transfer and back-up of the NPGS avocado collection in Miami to the NPGS genebank in Hilo as a means of protecting it from laurel wilt disease.

1) The curator and five staff continue management of the 14 designated clonal germplasm collections (app 1000 accessions) in 33 field acres, greenhouse & a tissue culture laboratory. C. papaya and Vasconcellea spp. seeds are regenerated every 4 years in PRSV-free fields and in greenhouses using controlled pollination. Cleaned seeds are stored at 4 C and storage units monitored electronically via a security company. A senior staff and the curator are on call for temperature alarm calls. Descriptors will be collected on plant and fruit morphologies and stored in a local database. Passport, inventory and descriptors information are periodically loaded onto the Germplasm Resource Information Network (GRIN). Survey of existing U.S. collections of tropical fruit genetic resources will be conducted; (2) Curator and scientists will work with Tropical/Subtropical Crop Germplasm Committee (CGC) members and the Plant Exchange Office to identify and collect germplasm already in the U.S. from University research collections and botanical gardens. Unit scientists will cultivate and establish working relationships with scientists in some Pacific Rim countries including the Philippines, Oceania, Vietnam and Thailand through participation in international germplasm conferences and meetings to identify potential resources of Sapindaceae (Litchi and rambutan relatives), Burseraceae (Canarium or pili nut relatives) and Moraceae (Artocarpus or breadfruit relatives). Information on NPGS germplasm policies, quarantine procedures and standard Material Transfer Agreements (MTA) will be collated and made available to cooperators to facilitate and encourage germplasm exchanges; (3) The research horticulturist will work with ARS scientists in Florida, Puerto Rico, and Mississippi to develop and apply SSR or SNP molecular marker technology for Litchi sp. (litchi), Ananas sp. (pineapple), Carica sp. (papaya), and related species (Vasconcellea and Jacaratia). Crop specific markers will be input into GRIN-Global with links to genetic observations. Thirty SSR molecular markers have been developed for Carica and will be compared to the newly developed SNP markers; and (4) The Hilo unit will follow a strict process in moving disease-free scionwood, after a designated quarantine period of visual inspection and testing for laurel wilt and ASBVd, from the Fort Detrick, MD quarantine facility to establish a NPGS avocado germplasm back-up in Hawaii. The scion will be grafted in Hilo onto clean rootstocks and confined in a quarantine facility for 4 to 6 months under supervision of the unit plant pathologist. Plants free from Laurel Wilt and ASBVd will be moved to a holding greenhouse for additional observations for four to six months before transplanting into larger containers and placing on elevated benches in the avocado germplasm screenhouse. Scion will be harvested from the germplasm collection for distribution or evaluation research.

Progress Report
Progress has been made on all four objectives from 5320-21000-014-00D, "Pacific Tropical/Subtropical Fruit and Nut Genetic Resource Management and Sustainable Production Systems". Under objective 1, we maintain 13 designated clonal germplasm collections with over 1000 accessions grown on 30 field acres, greenhouses and a tissue culture laboratory. Working closely with the USDA, ARS tropical germplasm repositories in Miami and Puerto Rico, we are continuing transfer of the USDA National Plant Germplasm System (NPGS) avocado germplasm from Miami to Hilo through Fort Detrick and maintaining 29 selected cacao, Theobroma cacao, accessions from Miami and Puerto Rico. We are currently assisting Miami with field trial evaluations of select cacao varieties on Hawaii Island. These cacao varieties will be tested in field trials on Hawaii Island, Oahu and Puerto Rico. Over the last year we have collected observations from the Ananas (pineapple) collection (3486 plant observations from 249 accessions; 544 flower observations from 136 accessions, and 1474 fruit observations from 67 Ananas accessions); 1 Dimocarpus (longan) accession (190 fruit observations); 2 Bactris (peach palm) accessions (85 fruit observations); 18 Litchi (lychee) accessions (5580 fruit observations) and 1 Carica (papaya) accession (150 fruit observations). Over the last year, five hundred eight (508) requests were filled for Carica/Vasconcellea - papaya (205), Ananas - pineapple (105), Psidium – guava (48), Artocarpus – breadfruit (16), Macadamia (15), Litchi – lychee (13), Mapighia – acerola (13), Averrhoa – starfruit (7), Canarium – pili nut (6), Dimocarpus – longan (6), Bactris - peach palm (5), Nephelium – rambutan (3), and others (66). We have surveyed the collection at the University of Hawaii College of Tropical Agriculture and Human Resources, Waiakea and Kainaliu Experiment Stations. At the Waiakea station, 15 macadamia accessions, not currently in the Hilo collection, have been identified and requested. This scion material will be girdled as grafting material once the rootstocks reach the appropriate size. In addition, 15 assorted accessions i.e. Eugenia, Feijoa, Averrhoa, Canarium, Dimocarpus, Theobroma cacao, Artocarpus and Litchi have been identified and collected. At the Kainaliu station, eight accessions, i.e. Litchi, Dimocarpus, Feijoa, and Psidium have been identified. Different propagation methods for Artocarpus are currently being explored, since once established these methods will be used to expand our Artocarpus collection from the accessions at the National Tropical Botanical Garden, Kahanu, Maui. Numerous gaps in our collection also have been identified at Fairchild Garden, Florida. The cost of shipment and the importation requirements are currently being investigated. Tissue cultured pineapple plants are being tested for pineapple mealybug wilt viruses and are being propagated to send to Fort Collins for the development of cryogenic storage protocols. Under objective 2, we are continuing our efforts to increase stakeholder contacts to obtain new accessions for our collection. We have established a framework for a protocol to facilitate compliance with import regulations and preparation and shipment of accessions to the repository. In addition, we are working closely with the National Germplasm Resources team to effectively update information on our collection in the internationsl Germplasm Resource information System (GRIN-Global) which should enhance collaboration with international partners. Under objective 3, we are optimizing the process to develop molecular markers for our Carica (papaya) collection. During the seed regeneration process, we are actively collecting plant material for molecular analysis. Under objective 4, thirty three (33) avocado accessions with no visible laurel wilt and tested free of Avocado Sunblotch viroid (ASBVd) were transferred to Hilo from Miami through Fort Detrick. Avocado sunblotch viroid (ASBVd) and laurel wilt (Raffaelea lauricola) testing protocols have also been established at the NPGS-Hilo. Plants are tested for ASBVd and laurel wilt prior to release from quarantine in Hilo. After quarantine and screening these trees are transplanted into larger containers and maintained in a screenhouse. To determine if Avocado Sunblotch and laurel wilt is already present in Hawaii, testing was completed on 11 field samples from Hawaii Island (5 from Hilo and 6 from Kona). All samples tested negative for both diseases by RT-PCR and PCR detection assays for ASBVd and R. lauricola, respectively.

1. Collect, maintain and distribute 13 designated tropical fruit and nut crop germplasm. ARS scientists in Hilo, Hawaii, provide long-term management of 1,000 living accessions of tropical fruit and nuts on 30 field acres, screenhouses, greenhouses, seed storage and tissue cultures. Over the last year, we collected over 11,000 observations on plant, flowers and fruits and distributed plant material for five hundred eight (508) requests from our germplasm collections. We continue to collaborate and serve as a backup for the avocado and cacao collections in Miami and Puerto Rico. The project contributes to positive economic and environmental impact worldwide by providing a reliable and sustainable resource of plant germplasm for research and utilization.

Review Publications
Heller, W.P., Z. Ying, T.L. Davenport, L.M. Keith, T.K. Matsumoto. 2014. Identification of members of the Dimocarpus longan Flowering Locus T gene family with divergent functions in flowering. Tropical Plant Biology. 7(1):19-29.
Keith, L.M., Zee, F.T. 2010. Guava diseases in Hawaii and the characterization of Pestalotiopsis spp. affecting guava. Acta Horticulturae. 849:269-275.