GRAPE GENETIC RESOURCES AND RESEARCH AT THE DAVIS CALIFORNIA NATIONAL CLONAL GERMPLASM REPOSITORY

Abstract

The Davis, California National Clonal Germplasm Repository (NCGR) houses most Mediterranean-adapted fruit and nut crop collections in the U.S., including grapes (Vitis). The NCGR is part of the USDA National Plant Germplasm System (NPGS). Our missions are to acquire, preserve, characterize, and distribute germ- plasm resources of our designated crops (http://www.ars.usda.gov/pwa/davis/ npgs). It is NPGS policy to distribute plant material, free of charge, to research interests around the world. The NCGR grape collection includes >2800 different accessions, including one of the world's finest Vitis species collections, -.600 V vinifera wine grape varieties, and —600 V i'inifera table grape varieties. Our sister repository in Geneva, NY houses the cold-hardy grape collection. At the Davis NCGR, genetic markers have been used intensively to assess diversit y, relatedness, and trueness to type within the collection. To date, DNA microsatellite and AFLP fingerprinting has been conducted on more than 700 NCGR grape accessions, including 366 V vinifera. Examination of genetic relationships across numerous Vitis species revealed genetic affinities roughly corresponding to taxonomic distinctions derived morphologically. Proper identifica- tion is a key concern since individual grape cultivars have been widely dispersed, with many synonyms, and often the same name used for different cultivars. Except for known or presumed bud-sports, a standard eight microsatellites have uniquely identified each genotype tested. Recent fingerprinting for V vinifera in European national collections should make it possible to verify identity of many of the J' vinifera varieties in our collection. We will complete standard fingerprinting of named cultivars in our collection by 2008.