Corylus americana: a valuable genetic resource for developing hazelnuts adapted to the eastern United States

Abstract

Corylus americana is native to a wide area of land in eastern North America, bounded by the Rocky Mountains in the west and the Atlantic Ocean in the east, and ranging from southern Canada to the southeastern US. The species has been shown to be highly genetically diverse and is adapted to a variety of climates and soils. It is also resistant to the disease eastern filbert blight (EFB) caused by the fungus Anisogramma anomala. Unfortunately, C. americana has thick-shelled, tiny nuts that make it unsuitable for commercial production. However, it is cross-compatible with the commercial hazelnut C. avellana and can serve as a donor for genes for disease resistance, early nut maturity, cold tolerance, etc. As part of the Hybrid Hazelnut Consortium consisting of Rutgers University, Oregon State University, the University of Nebraska-Lincoln, and the Arbor Day Foundation, we have been successfully collecting C. americana germplasm since 2009 with the help of partners, colleagues, and the interested public around the USA. Today, we have a planting established in the field at Rutgers University in New Jersey that holds 1,899 seedlings obtained from 128 individual seed lots that span 23 states and one Canadian province. These bushes are being evaluated for EFB response, other diseases and insects, flowering and vegetative bud break phenology, cold hardiness, nut yield, and nut and kernel characteristics. The genetic diversity and population structure of the new collection is also being evaluated using several approaches, including genotyping by sequencing and subsequent SNP analysis, SSR allelic variation, and chloroplast haplotype determination across the large population. Using this multi-faceted approach, we hope that superior, diverse selections can be identified for use in systematic breeding efforts to develop new cultivars adapted to the eastern USA, especially in respect to consistent cropping in regions with highly variable year-to-year climates.