Comparison of Accessions from the UK and US National Pear Germplasm Collections with a Standardized Set of Microsatellite Markers

摘要

A standardized set of 12 microsatellite markers; previously agreed upon following an ECP/GR workshop in 2006, was used to screen accessions from the UK National Pear Collection at Brogdale and from the US National Pear Collection at the United StatesDepartment of Agriculture (USDA), Agricultural Research Service (ARS), National Clonal Germplasm Repository (NCGR) in Corvallis, Oregon. Eight standard cultivars were chosen from the UK collection and freeze-dried leaves were provided to the US group toallow harmonization of calling amplification product sizes. Comparison of the data from 61 accessions revealed 41 pairs of individuals with the same name and with identical allele sizes. Twelve accessions from Brogdale were different from those with thesame name at NCGR at more than six of the 12 microsatellite loci indicating the possibility of mis-identified trees. Six accessions from Brogdale were identical to those with the same name at NCGR at 11 of the 12 microsatellite loci. Detailed comparisonsof electropherograms revealed that three of these were in fact mis-scored and consequently these accessions can also be added to the original 41 identical pairs. Two accessions from Brogdale were identical to those with the same name at NCGR at 10 of the 12 microsatellite loci. Further comparison of electropherograms and comparison of phenotypic data is required before these accessions can be confirmed as different. Characterization of germplasm collections at this level should result in more accurateidentification of accessions reducing the possibility of error when attempting to compare results between cultivars that may be mis-labeled.