RAPD markers linked to eastern filbert blight resistance in

A total of 1,110 decamer primers were screened for RAPD markers linked to a dominant allele in hazelnut (Corylus avellcma) that confers resistance to eastern filbert blight caused by A~zisogrcrinmn anomnl~z. Twenty R 4 P D markers linked in coupling, and five markers linked in repulsion. were found. A seedling population was used to construct a linkage map of the region flanlung the resistance locus. The map spans 46.6 ch1, with 1 1 markers on one side of the resistance locus and eight on the other side. Eleven markers showed less than 3% recombination with resistance, including three that showed no recombination. Seven of these 11 markers are sufficiently robust to allow their use in marker-assisted selection. These include XX138i,) which shows no recornbination, and six markers on one side of the resistance locus: 17350~), 152Roo, l?3Y25. 275,,;0, H19hsi, and 016,250. Marker 268580, which flanks the resistance locus on the other side, is also suitable for use in marker-assisted selection. but shows 5.8% recombination with resistance. Other markers are less suitable for marker-assisted selection because of sensitivity to changes in primer or kfsC12 concentration, or the long time required for electrophoresis to separate bands of similar size. The I6 markers closest to the resistance locus were cloned and secluenced. The W07:h marker. which showed no recombination with the rejistance locus but is difficult to score. includes a CT rnicrosatellite repeat. The jequznce information will allow the design of SCAR primers and eventual rn~~p-hased cloning of the resistance allele. Coinrnun~c~ied hq D B. Ycale S. X. .Clehienbacher i:<j R. N. Brown J . W D a \ i \ H. Chen N . V B;l\\~i D. C . Srn~th Department of Hon~culture, Orcgon State C'ntvtr\it). 401 7 r\LS Bt~iidiny, Corvalii\. OK 0733 1 , CS.-\ e-ina11: mehlenb\~ii . \c~eni 'e .ortgo~~\[~ite . i : t l t~ TeI.: +I-5.11 -7375467 Fax: + 1 5 1 1-7373170