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United States Department of Agriculture

Agricultural Research Service

Research Project: Management of Tropical/subtropical Plant Genetic Resources and Associated Information

Location: Tropical Crops and Germplasm Research

2013 Annual Report


1a.Objectives (from AD-416):
1. Efficiently and effectively conserve, back-up, regenerate, and evaluate tropical and subtropical fruit, bamboo, and cacao genetic resources and distribute them and associated information worldwide.

2. Aided by genetic marker information, strategically fill gaps in the current coverage of tropical and subtropoical fruit, bamboo, and caco germplasm collections through international exchanges.

3. In collaboration with other NPGS genebanks and research projects, develop novel genetic marker systems for tropical and subtropical fruit, bamboo, and caco genetic resources. Apply those markers to more efficiently and effectively manage genetic resources and facilitate their use in breeding and research projects.


1b.Approach (from AD-416):
Plant genetic resources will be efficiently and effectively conserved, backed-up, regenerated, evaluated, and distributed free of diseases. This will be carried out by implementing latest technologies available for field, lab, and greenhouse plant labeling, by maintaining on and off-site backups of critically important germplasm, by field evaluating for important horticultural traits and by indexing/eliminating plant diseases in stock to be distributed. All information associated with plant genetic resources including passport, characterization, and evaluation data will be incorporated into the publicly available GRIN database. The development of molecular marker tools for systematic characterization of the site's plant germplasm is a collaborative effort with other USDA-ARS laboratories. Marker tools developed in collaboration will aid in the identification of redundancies, discrepancies, and genetic gaps in the collections. In addition, the marker work will complement morphological characterization and stakeholder community input in the development of guidelines to follow for prioritization of future plant introductions.


3.Progress Report:
This research project is service oriented. The number of germplasm distributions amounted to 222 distributions of 228 different accessions with a total of 11802 propagules. Tropical germplasm was distributed in the form of budwood, cuttings, rhizomes, corms, seed and fruit, and was made available and distributed to researchers and cooperators at the local, national and international level.

Passport information has been updated and descriptors from characterizations as well as voucher images have been loaded into GRIN for the cacao, mamey sapote, Musa spp. and miscellaneous collections.

Fifty Musa spp. accessions were planted in the field as part of a collaborative project with Bioversity International’s Musa International Transit Center. These plants have been in tissue culture for over 10 years in the international collection and need to be field verified and characterized for important phenotypic and agronomic traits. Also in collaboration with Bioversity International, our site is in the process of in vitro propagating and later field establishing 10 introduced Sigatoka disease-resistant Musa spp. clones for field evaluation.

The Musa spp. field germplasm collection has been re-established at the USDA-ARS TARS research farm in Isabela. The field site was infested with Fusarium wilt therefore, two plants established from the tissue culture backup collection will be used as this is the only source of disease-free stock. Several new accession introduced will be incorporated in this field planting.

A collection of close to 200 cacao (Theobroma cacao L.) samples from naturalized trees on the island of Puerto Rico has been assembled. DNA was extracted and genotyped with a set of 100 single nucleotide polymorphism (SNP) makers to assess genetic diversity and for incorporation of unique germplasm into the existing collection. The same set of SNP markers is being used to genotype the existing cacao germplasm accessions. Data generated is in the process of being analyzed and fingerprint profiles will be loaded into GRIN.

Cacao germplasm continues to be introduced from the USDA-ARS Subtropical Horticulture Research Station quarantine facilities (~20 new T. cacao accessions were introduced). In addition, four new Theobroma spp. and five new Herrania spp. accessions were introduced (donated) into the collection from a local cooperator.

Three new Garcinia species (G. magnifolia, G. hombroniana, G. gardneriana/G. humilis) have been added to the priority collection and were introduced (donated) from a local cooperator.

A planting of F5 papaya of Line 41 was made for screening for Papaya Ringspot Virus tolerance, high brix and intermediate fruit size at the Isabela Research Farm.

A third year of data is being collected in the Annona spp. germplasm collection. Data collected includes number and weight of fruit, fruit size, and Brix value. Data is shared with the location’s Research Entomologist who is evaluating pheromone treatments within the same germplasm collection.

This project replaced project 6635-21000-047-00D which terminated in March 2013.


Last Modified: 11/23/2014
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