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RAPD markers linked to eastern filbert blight resistance in Corylus avellana
S A Mehlenbacher1, R N Brown, J W Davis
1Department of Horticulture, Oregon State University, 4017 ALS Building, Corvallis, OR 97331, USA. mehlenbs@science.oregonstate.edu
Summary
Researchers identified robust RAPD markers linked to hazelnut (Corylus avellana) resistance against eastern filbert blight. These markers are crucial for marker-assisted selection in breeding programs.
Area of Science:
- Plant genetics
- Molecular markers
- Disease resistance breeding
Background:
- Eastern filbert blight, caused by Anisogramma anomala, is a major disease affecting hazelnut (Corylus avellana) production.
- Developing resistant hazelnut varieties is crucial for sustainable agriculture.
Purpose of the Study:
- To identify Random Amplified Polymorphic DNA (RAPD) markers linked to a dominant resistance allele for eastern filbert blight in hazelnut.
- To construct a genetic map of the region surrounding the resistance locus.
- To evaluate the suitability of identified markers for marker-assisted selection (MAS).
Main Methods:
- Screening of 1,110 decamer primers for RAPD markers.
- Construction of a linkage map using a seedling population.
- Analysis of recombination frequencies between markers and the resistance locus.
- Cloning and sequencing of markers closest to the resistance locus.
Main Results:
- Twenty RAPD markers linked in coupling and five in repulsion were identified.
- A linkage map spanning 46.6 cM was constructed, with 14 markers on one side and eight on the other side of the resistance locus.
- Eleven markers showed less than 3% recombination with resistance, with three showing no recombination.
- Seven markers, including AA12(850), were deemed robust for marker-assisted selection.
- Marker W07(365) showed no recombination but contained a CT microsatellite repeat.
Conclusions:
- Several RAPD markers are tightly linked to the eastern filbert blight resistance locus in hazelnut.
- These markers, particularly those with low recombination rates, are valuable tools for marker-assisted selection in breeding programs.
- Sequence information of selected markers facilitates the design of Sequence Characterized Amplified Region (SCAR) primers for future map-based cloning efforts.