Survey of hazelnut cultivars for response to eastern filbert blight inoculation

Ninety hazelnut (Corylus sp.) genotypes were surveyed for response to the eastern filbert blight pathogen [Anisogramma anomala (Peck) E. Muller] following greenhouse inoculation using a combination of enzyme-linked immunosorbent assay (ELISA) and visual inspection for cankers. Most were cultivars of the European hazelnut (Corylus avellana L.) and a few were interspecific hybrids. Six genotypes did not display signs of the pathogen or symptoms of disease 'Closca Molla', 'Ratoli','Yoder #5', 'Potomac', 'Medium Long', and 'Grand Traverse'. 'Closca Molla' and 'Ratoli', both minor Spanish cultivars, are superior in many respects to 'Gasaway', which has been extensively used as a completely resistant parent in breeding. 'Potomac' and 'Yoder #5' have C. americana Marsh. in their pedigrees,'Grand Traverse' is one-quarter C. colurna, and the origin of 'Medium Long' is uncertain. The random amplified polymorphic DNA (RAPD) marker generated by primer UBC 152, which is linked to the single dominant resistance gene of 'Gasaway', is absent in these six genotypes, and thus they appear to be novel sources of genetic resistance to this devastating disease.