ISHS Acta Horticulturae 596: VIII International Symposium on Pear
ELIMINATION OF VIRUSES FROM THE USDA PYRUS GERMPLASM COLLECTION |
| Authors: | J.D. Postman, D. Sugar |
| Keywords: | pear, Pyrus, in vitro, cultivar, virus, conservation |
| Abstract:
The national genebank for Pyrus in the U.S.A. is maintained by the United States Department of Agriculture, Agricultural Research Service at the National Clonal Germplasm Repository in Corvallis, Oregon. This collection represents world diversity for pears and includes over 1700 accessions representing the 26 major taxa of Pyrus and their hybrids. Clonal genotypes are stored as orchard trees with approximately 10% of the collection backed up as in vitro cultures. Wild species are represented as orchard trees and as seed collections. Clonal accessions are screened for latent viruses by graft inoculation to a range of woody indicator plants. Since 1983 more than 650 virus-infected pear clones have been detected in the collection. Infected clones are subjected to alternating temperature heat-therapy followed by apical meristem culture to generate virus-free replacement plants. More than 400 virus-infected clones have been replaced with heat-treated meristem derived trees. Presently, 77% of the clonal Pyrus accessions and more than 86% of the pear cultivars at the U.S. pear genebank are available as virus tested trees. | |
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