Overview of the Tropical Genetic Resources Program At the USDA-ARS Tropical Agriculture Research Station

The lack of well established, organized, characterized and properly maintained germplasm collections could mean the loss of potentially useful genetic resources for a given crop species.  As part of the National Plant Germplasm System (NPGS) and in a long-term effort for the conservation of plant genetic resources under USDA-ARS National Program 301 (Plant Genetic Resources, Genomics and Genetic Improvement), the Tropical Agriculture Research Station’s (TARS) germplasm program in Mayaguez, Puerto Rico, curates tropical and subtropical plant germplasm.  In addition to a number of tropical and subtropical fruit collections, the program is responsible for the curation of cacao (Theobroma cacao), both tropical and temperate bamboo collections as well as tropical woody and herbaceous ornamentals.  The program’s main responsibilities are to acquire, propagate in a disease-free manner, maintain, characterize, evaluate and distribute (for research and educational purposes) plant germplasm.  Characterization efforts focus on phenotypic traits useful in distinguishing among accessions as well as morphological traits of agronomic importance.  Molecular markers are utilized for the identification of mislabeling, understanding genetic relationships among accessions, estimating genetic diversity and identifying genetic gaps within the collections.  Recent efforts have focused on a collaborative project for the development of microsatellite or SSR markers for a number of tropical crop germplasm collections maintained at USDA-ARS NPGS repository sites.  All passport, morphological (including voucher images) and molecular data for accessions are publicly accessible through the Genetic Resources Information System (GRIN) database.  Results from recent research conducted on tropical genetic resources at TARS are discussed further.