Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/10/2003
Publication Date: 10/21/2003
Citation: MEHLENBACHER, S.A., BROWN, R.N., DAVIS, J.W., CHEN, H., BASSIL, N.V., SMITH, D.C. 2003. RAPD MARKERS LINKED TO EASTERN FILBERT BLIGHT RESISTANCE IN CORYLUS AVELLANA. 108:651-656 Interpretive Summary: Random amplified polymorphic DNA (RAPD) markers, generated by the polymerase chain reaction (PCR), are one of the least expensive of the available genetic markers and are easy to use in traditional breeding programs. More than 1,400 small pieces of DNA called primers were used to identify marked locations close to a gene in hazelnut. This gene confers resistance to eastern filbert blight. Twenty five markers were found. A seedling population was used to make a map of the region surrounding the gene. The map has 14 markers on one side and eight on the other side. Seven markers are sufficient for 'marker-assisted selection' (MAS). MAS quickly identifies seedlings that are resistant. The sequence or code of the 16 markers closest to the gene were determined. The sequence is important because it will make further research on the gene easier to do.
Technical Abstract: A total of 1420 decamer primers were screened for RAPD markers linked to a dominant allele in hazelnut (Corylus avellana), that confers resistance to eastern filbert blight caused by Anisogramma anomala. Twenty RAPD markers linked in coupling and five additional markers linked in repulsion were found. A seedling population was used to construct a linkage map of the region flanking the resistance locus. The map spans 48.1 cM, with 14 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. Other markers are less suitable for marker-assisted selection because of sensitivity to changes in primer or MgCl2 concentration, or the long time for electrophoresis to separate bands of similar size. The 16 markers closest to the resistance locus were cloned and sequenced. The W07375 marker, which showed no recombination with the resistance locus but which is difficult to score, includes a CT microsatellite repeat. The sequence information will allow the design of SCAR primers and eventual map-based cloning of the resistance allele.