ARS | Publication request: Identification of European and Asian Pears Using EST-SSRs From Pyrus

Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 13, 2009
Publication Date: September 11, 2009
Citation: Bassil, N.V., Postman, J.D. 2009. Identification of European and Asian Pears Using EST-SSRs From Pyrus. Genetic Resources and Crop Evolution. 57:357-370..

Interpretive Summary: The objective of this study was to estimate the usefulness of genetic tools (referred to as microsatellite markers) in managing the USDA-ARS pear germplasm collection, in Corvallis, Oregon. Ten previously developed markers were used in a set of 144 pear varieties from three different types of pear. They proved very valuable for identification of incorrectly identified accessions, failed grafts and sets of synonyms in each of the pear types. Unsuspected relationships were uncovered, including a parental relationship between ‘Anjou’ and ‘Farmingdale’, a clonal relationship between ‘Berger’ and ‘Bartlett’, and a very close relationship between ‘Beurre Superfin’ and ‘Doyenne du Comice’. One marker was different in one of three sports of ‘Doyenne du Comice’ (‘Doyenne du Comice Crimson Gem’) and in one of two sports of ‘Anjou’ (‘Gebhard Red’ red skin sport of ‘Anjou’). The pears were separated into a large European group and an Asian group mostly according to common ancestry, geographical origin or time of ripening. These markers are valuable for germplasm management in such a highly diverse collection as found at the NCGR Pyrus genebank in Corvallis, OR.

Technical Abstract: Ten EST-SSRs previously isolated from Pyrus were used to identify 81 P. communis, 13 P. pyrifolia and 20 P. ussuriensis or P. × bretschneideri accessions. Cross-transference of these EST-SSRs was high in these species. PYC-008 and PYC-004 were the least informative SSRs in each of the pear species and were monomorphic in P. pyrifolia while PYC-013, PYC-002 and PYC-009b were the most informative in all species. EST-SSRs were very valuable for identification of incorrectly identified accessions, failed grafts and sets of synonyms in each of the species. Unsuspected relationships were uncovered, including a parental relationship between ‘Anjou’ and ‘Farmingdale’, a clonal relationship between ‘Berger’ and ‘Bartlett’, and a very close relationship between ‘Beurre Superfin’ and ‘Doyenne du Comice’. One SSR marker was different in one of three sports of ‘Doyenne du Comice’ (‘Doyenne du Comice Crimson Gem’) and in one of two sports of ‘Anjou’ (‘Gebhard Red’ red skin sport of ‘Anjou’). UPGMA cluster analysis separated the pear accessions into a large European cluster and an Asian group mostly according to common ancestry, geographical origin or time of ripening. High cross-transference of EST-SSRs in Pyrus species is very valuable for germplasm management in such a highly diverse collection as found at the NCGR Pyrus genebank in Corvallis, OR.