Shawn Mehlenbacher

Professor, Hazelnut Breeding and Genetics
shawn.mehlenbacher [at]

Office: 541-737-5467
Fax: 541-737-3479

Agricultural & Life Sciences

Agricultural & Life Sciences 4145

2750 SW Campus Way

2750 SW Campus Way
Corvallis, OR 97331

The OSU Hazelnut Breeding program develops new cultivars for Oregon's hazelnut industry, with an emphasis on resistance to eastern filbert blight (EFB) and suitability for the kernel market.

Plant Breeding: Develop new cultivars for Oregon's hazelnut industry, with emphasis on resistance to eastern filbert blight (EFB) and suitability for the kernel market. Practice marker-assisted selection using robust DNA markers linked to the dominant resistance allele from 'Gasaway'. Improve breeding methods and efficiency. Collect hazelnut germplasm from around the world, evaluate, and use interesting accessions as parents in breeding. Cooperate with Rutgers University, the University of Nebraska at Lincoln, and the National Arbor Day Foundation to develop interspecific hazelnut hybrids (Corylus americana x C. avellana) adapted to eastern North America.

Plant Genetics. Identify additional sources of resistance to eastern filbert blight, study genetic control, and identify or develop DNA markers linked to the new sources of resistance. Develop microsatellite markers and assign the loci to linkage groups. Use microsatellite markers to fingerprint accessions and study genetic variability in Corylus. Obtain information on the genetic control of traits. Identify the S-alleles that control pollen-stigma incompatibility in hazelnut cultivars and selections. Perform fine mapping and map-based cloning of the incompatibility in hazelnut, and investigate its molecular basis. Cooperate with colleagues in sequencing the genome of 'Jefferson' and two other hazelnut selections.  Add genotyping-by-sequencing markers to the linkage map.  Integrate the linkage map, Pacific Biosciences genome sequence, and physical map of bacterial artificial chromosomes (BACs). 

Profile Field Tabs

Affiliated with: 
Do you accept grad students?: 
I accept graduate students for Horticulture
Courses Taught: 

I teach Plant Breeding (HORT/CSS 450/550) annually and Breeding Clonal Crops (HORT 505) in alternate years. I contribute to Temperate Tree Fruits, Berries, Grapes and Nuts (Hort 251), World Food Crops (CSS 330). Research and Educational Perspectives in Horticulture (HORT 511).

My Publications


Journal Article

S. A. Mehlenbacher, Smith, D. C., and McCluskey, R. L., ‘Burgundy Lace’ Ornamental Hazelnut, HortScience, vol. 53, no. 3, pp. 387 - 390, 2018.


Journal Article

G. Bhattarai, Mehlenbacher, S. A., and Smith, D. C., Inheritance and Linkage Mapping of Eastern Filbert Blight Disease Resistance in ‘Uebov’ Hazelnut, Journal of the American Society for Horticultural Science, vol. 142, no. 4, pp. 289 - 297, 2017.