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United States Department of Agriculture

Agricultural Research Service

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

Location: Tropical Plant Genetic Resources and Disease Research

2013 Annual Report


1a.Objectives (from AD-416):
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.


1b.Approach (from AD-416):
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.


3.Progress Report:
This report documents progress for this new project which started March 6, 2013, and continues the research from Project 5320-21000-012-00D, "Pacific Fruit Genetic Resource Management and Sustainable Production Systems".

Progress has been made on three of the four objectives which fall under National Program 301, Component 2: Crop Genetic and Genomic Resources and Information Management; Problem Statement 2B: Plant and Microbial genetic resource and information management. Under Objective 1, we conducted daily maintenance of current collection of 1000+ accessions. Tissue cultured Ananas comosus accessions tested free of internal bacteria contamination in Hilo, Hawaii, and were provided to Fort Collins, Colorado, for cryogenic storage protocol development. The papaya seed storage units and alarm system of the unit were upgraded. Under Objective 2, we visited abandoned macadamia selection plots in the University of Hawaii to identify potentially useful germplasm. International germplasm contacts in Australia, China and Japan were maintained and expanded. The updated Plant Germplasm Operations Committe (PGOC) operation manual was studied and a simplified quick reference to germplasm exchange procedures for unit reference was drafted. Under Objective 4, quarantine transfer of the USDA, ARS, National Plant Germplasm System (NPGS) avocado collection from Miami, Florida, to Hilo, Hawaii, to protect it from the laurel wilt disease was continued. Twenty-three accessions from the initial transfer are planted in larger containers in the isolated screenhouse as a base collection, and additional support for screenhouse space for the avocado project has been secured. Reviewed the Avocado Sunblotch Viroid (ASBVd) test kit quality to assure quarantine security. ASBVd testing protocols have been established at the ARS Tropical Plant Genetic Resources and Disease Research Unit (TPGRDR), Hilo, Hawaii. Testing of avocado backup samples from Miami, Florida, has commenced. Avocado rootstocks are ready for 10 additional disease free accessions to be transferred from Fort Detrick, Maryland.


Last Modified: 9/1/2014
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