The 2012 ASHS Annual Conference

European hazelnut (Corylus avellana L.) is a high-value, low-input crop traditionally grown in Mediterranean regions.  Its production in the U.S. is limited due to its susceptibility to the devastating fungal disease eastern filbert blight (EFB), which is found only in North America. Currently, there are limited sources of genetic resistance to this disease found in C. avellana.  Development of hazelnuts with stable genetic resistance could significantly increase the acres of hazelnut production in the U.S.  At Rutgers, the screening of large germplasm collections of C. avellana from Eastern Europe and parts of Russia has identified numerous new plants expressing resistance to EFB.  However, other than geographic origin, little is known about the genetic diversity and relatedness of these new potential sources of resistance. In this study, 170 EFB-resistant and tolerant seedlings, as well as 179 known cultivars and breeding selections representing a wide spectrum of geographic origins and a number of known sources of EFB-resistance, were assessed using thirty genomic SSR markers.  The goal was to examine the relatedness and genetic diversity present in and among the new seedlings to identify potential novel sources of EFB-resistance, as well as to evaluate the seedlings in respect to known cultivars and existing sources of EFB resistance.  The resulting SSR data was used to evaluate polymorphism information content, allele frequencies, and heterozygosity.  Additionally, cluster analysis was performed on the data and relationships were resolved between new EFB resistant seedlings and standard cultivars known to confer disease resistance.  By better understanding genetic diversity in the new germplasm, the hazelnut breeding program will be able to direct its efforts into utilizing and maintaining multiple, unrelated sources of resistance in its breeding lines, where goals of developing durable, long-lasting resistance to EFB is a priority.