43 The National Plant Germplasm System: the Subtropical and Tropical Fruit Gene Banks T.A. Silva 1,a , R. Schnell 1 , R. Goenaga 2 , F. Zee 3 and B. Irish 2 1 USDA, ARS, National Germplasm Repository, Subtropical Horticultural Research Station, 13601 Old Cutler Road, Miami, FL, 33158, USA 2 Tropical Agriculture Research Station, 2200 Pedro Albizu Campos Av. Suite 201, Mayaguez, PR, 00680, USA 3 USDA, ARS Pacific Basin Tropical Plant Genetic Resources Management Unit, P.O. Box 4487 Hilo, HI, 96720, USA Keywords: accessions, characterization, collections, evaluation, GRIN, NPGS Abstract The National Plant Germplasm System (NPGS) is a network of 29 repositories nationwide that preserve and regenerate seed and other tissues of crop plants and their wild relatives. The system houses more than 500,000 accessions comprising over 2100 genera and more than 13,100 species. The NPGS has collections for about 85 major crops. It is one of the world’s largest collectors and distributors of germplasm. This public germplasm management system has yielded large economic benefits to public and private organizations worldwide. Plant genetic resources (PGRs) serve as the basic materials for research and development to sustain agricultural productivity. They provide useful characteristics and genes for food, feed, fiber, ornamental, and energy uses. Endangered globally by human and natural forces, their conservation is essential to the wealth and future of mankind. The NPGS research programs are dedicated to answering questions that help curators and researchers conserve and manage genetic resources in a more effective and cost-efficient manner. Characteriza- tion and evaluation information is collected by curators, staff and researchers on agronomic performance, biochemical, genetic, phenotypic traits and qualities. Digital images are captured to provide useful detail on plant, fruit and seed structures, and permanent information for reference use. Analysis of highly heritable traits supports taxonomic identification and quality assurance. Information on their adaptation, maturity, and reactions to envi- ronmental or physical stress is valuable to researchers. This paper examines PGRs held at three clonal repositories for tropical/sub- tropical fruit crops. These are the Subtropical Horticultural Research Station (SHRS) in Miami, FL, the Tropical Agriculture Research Station (TARS) in Mayaguez, PR, and the Tropical Plant Genetic Resource Management Unit (TPGRMU) in Hilo, HI. INTRODUCTION The United States Department of Agriculture’s National Plant Germplasm System (NPGS) is responsible for managing plant genetic resources in the United States of America. The NPGS provide a continuous flow of genes from source to end use, a continuum that keeps high-yielding cultivars on the market; improves the quality of agricultural products; minimizes production costs; reduces dependence on pesticides, thus enhances the quality of the environment; and minimizes the vulnerability of agriculturally important germplasm to pests and environmental stresses (NPGS, 2008a). The system houses more than 500,000 accessions comprising over 2100 genera and more than 13,100 species (NPGS, 2008c).The maintenance of “off-site conservation” germplasm collections for plants has become the primary means for preserving genetic diversity. As environmental degradation and sprawl continues, the associated loss of species diversity makes ex situ collections, in some cases, the last pool for genetic variation. Moreover, these collections are the only place where material is catalogued and evaluated, thus a tomas.ayala-silva@ars.usda.gov Proc. 4 th International Symposium on Tropical and Subtropical Fruits Eds.: Endah Retno Palupi et al. Acta Hort. 975, ISHS 2013