2019 ASHS Annual Conference

Eastern Filbert Blight (EFB) is a fungal disease caused by Anisogramma anomala and is the primary limitation to commercial hazelnut production in the Eastern United States. Controlling this disease is difficult because not only are fungicide sprays costly, but they are often ineffective against this pathogen. Therefore, breeding for resistance is the best long-term control method to combat the destructive EFB. In order to undertake this project, a pool of genetically diverse germplasm was obtained. The purpose of this diverse pool for the project was to evaluate a large collection of hazelnut seedlings for their individual resistance to EFB, commercially acceptable kernel characteristics, and subsequently correlate this information to the genetic backgrounds of the seedlings to create a referential knowledge base of informed breeding decisions. In 2004/2005, 855 open-pollinated hazelnut seeds were collected from Turkey, Latvia, and Lithuania. After over 10 years of their being exposed to A. anomala both in humidity chambers and in the field, 24 accessions were shown to have resistance or tolerance to EFB. After 5 years of nut evaluations, including percentage shell, kernel weight and kernel sphericity, and blanching, nearly all 24 accessions showed diverse, albeit commercially acceptable quality. Concurrently, the 24 accessions were genetically fingerprinted using simple sequence repeat (SSR) markers to determine their genetic similarity to each other, as well as to previously characterized cultivars and accessions. Only four of the 24 accessions were found to be over 50% genetically similar to previously characterized accessions/cultivars. The majority of the new EFB resistant/tolerant plants with relatively good nut quality and genetically unique backgrounds are potentially highly valuable additions to the U.S. hazelnut breeding programs.