Author
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Postman, Joseph |
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Submitted to: Acta horticulturae
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 11/20/2007 Publication Date: 6/20/2008 Citation: Postman, J.D. 2008. The USDA Quince and Pear Genebank in Oregon, A World Source of Fire Blight Resistance. Acta Horticulturae. 793:357-362. Interpretive Summary: The U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), operates the National Clonal Germplasm Repository in Corvallis, Oregon for the conservation of temperate fruit and nut crops. Globally diverse collections of pear (Pyrus species), quince (Cydonia oblonga), and other related fruits are preserved at this genebank. Unique varieties are maintained as growing plants, evaluated for important traits, tested for virus contamination, documented in a national public database, and freely distributed to requestors around the world. Seeds are stored in a freezer to represent wild plant populations. The Corvallis genebank maintains more than 2000 varieties of pear trees and more than 100 varieties of quince. Many pear accessions are resistant to the bacterial disease fire blight, but none of the quince accessions are known to be resistant. The disease does not normally develop in western Oregon’s Willamette valley because temperatures are too cool during bloom, and the weather is too dry in the summer when temperatures are higher. Since fire blight is rare in this part of Oregon, the location is an ideal place to maintain preservation orchards of both disease resistant and disease susceptible fruit tree varieties. Technical Abstract: The U.S. Department of Agriculture (USDA), Agricultural Research Service (ARS), has operated a genebank for temperate fruit and nut crops in Corvallis, Oregon since 1981. This facility, the National Clonal Germplasm Repository (NCGR), is devoted to conservation of many Rosaceous species that are potential hosts for fire blight (Erwinia amylovora (Burrill) Winslow). Globally diverse collections of Amelanchier, Cydonia, Mespilus, Pyrus, and Sorbus germplasm have been assembled at the Corvallis genebank. Unique genotypes are maintained as growing plants, evaluated for phenotypic and genotypic traits, tested for virus contamination, documented in a national public germplasm database, and freely distributed to international researchers. Seed collections represent wild species populations. The NCGR Cydonia collection includes more than 100 clones and 14 seedlots from 15 countries. Fire blight resistance has not been documented in the Cydonia germplasm, however, many recent introductions from the quince center of origin in central Asia and the trans-Caucasus region have yet to be evaluated. The NCGR Pyrus collection includes 2030 clonal pear accessions and 327 seedlots representing 36 Pyrus taxa from 53 countries. More than 160 pear clones are identified as being highly to moderately resistant to fire blight. Temperatures in western Oregon's Willamette Valley are normally below the threshold necessary for spread of fire blight during Cydonia and Pyrus bloom periods, and the weather is dry in the summer, making NCGR-Corvallis an ideal location to preserve these living germplasm collections for future generations. |
