Shawn Mehlenbacher
Professor, Hazelnut Breeding and Genetics

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.  

OSU Campus
Department of Horticulture
4017 Ag and Life Sciences Bldg
Corvallis, OR 97331-7304
United States
(541) 737-5467

Research

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 EFB resistance gene from 'Gasaway'. 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' hazelnut, and develop new polymorphic markers from microsatellites and single nucleotide polymorphisms in the sequence. Assist in sequencing additional hazelnut cultivars.

Teaching

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) and Discussions in Plant Science (HORT 512).

Biography

Academic Training
Ph.D. Plant Breeding
Cornell University, 1982

B.S. Horticulture
Pennsylvania State University, 1978

Professional Work Experience
Oregon Hazelnut Industry Professor, Oregon State University
2000-present.  Responsibilities: Tree Crop Breeding

Professor, Oregon State University
7/95-present. Responsibilities: Tree Crop Breeding

Associate Professor, Oregon State University
7/90-6/95. Responsibilities: Tree Crop Breeding

Assistant Professor, Oregon State University
9/86-6/90. Responsibilities: Tree Crop Breeding

Assistant Professor Rutgers University (NJ)
9/82-9/86. Responsibilities: Tree Fruit Breeding

I accept graduate students for Horticulture

Outreach and Extension

I regularly give presentations to Oregon's hazelnut growers at the annual meeting and summer tour of the Nut Growers Society of Oregon, Washington and British Columbia. I report research results to the Oregon Hazelnut Commission. The Arbor Day Foundation takes the lead in outreach by the Hybrid Hazelnut Consortium (www.arborday.org/programs/hazelnuts/consortium/).

Publications

Colburn, B.C., S.A. Mehlenbacher and V.R. Sathuvalli.  2014.  Development and mapping of microsatellite markers from hazelnut transcriptome sequences.  Molecular Breeding (in preparation). 

Colburn, B.C., S.A. Mehlenbacher, V.R. Sathuvalli and D.C. Smith.  2014.  Novel sources of eastern filbert blight resistance in hazelnut accessions 'Culpla', 'Crvenje' and OSU 495.072.  HortScience 49 (in preparation). 

Sathuvalli, V.R. and S.A. Mehlenbacher.  2014.  High resolution genetic and physical mapping of the eastern filbert blight resistance region in ‘Jefferson’ hazelnut (Corylus avellana L.).  (in preparation). 

Ives, C., V.R. Sathuvalli, B.C. Colburn and S.A. Mehlenbacher.  2014.  Mapping the incompatibility and style color loci in two hazelnut progenies.  HortScience 49:250-253. 

Mehlenbacher, S.A.  2014.  Geographic distribution of incompatibility alleles in cultivars and selections of European hazelnut.  J. Amer. Soc. Hort. Sci. 139:191-212.  

Mehlenbacher, S.A., D.C. Smith and R.L. McCluskey.  2014.  'Wepster' hazelnut.  HortScience 49:346-349.   

Mehlenbacher, S.A., D.C. Smith and R.L. McCluskey.  2013.  'Dorris' hazelnut.  HortScience 48:796-799.

Molnar, T.J, E. Walsh, J.M Capik, V. Sathuvalli, S.A. Mehlenbacher, A.Y. Rossman and N. Zhang.  2013.  A real-time PCR assay for early detection of eastern filbert blight.  Plant Disease 97:813-818. 

Sathuvalli, V.R. and S.A. Mehlenbacher.  2013.  De novo sequencing of hazelnut bacterial artificial chromosomes (BACs) using multiplex Illumina sequencing and targeted marker development for eastern filbert blight resistance.  Tree Genetics and Genomes (DOI 10.1007/s11295-013-0626-8) 

Rowley, E.R., S.E. Fox, D.W. Bryant, C.M. Sullivan, H.D. Priest, S.A. Givan, S.A. Mehlenbacher and T.C. Mockler.  2012.  Assembly and characterization of the European hazelnut 'Jefferson' transcriptome.  Crop Sci. 52:2679-2686. 

Bassil N., Boccacci P., Botta R., Postman J. and Mehlenbacher S.  2012.  Nuclear and chloroplast microsatellite markers to assess genetic diversity and evolution in hazelnut species, hybrids and cultivars.  Genetic Resources and Crop Evolution (on-line)  DOI 10.1007/s10722-012-9857-z 

Sathuvalli, V.R., S.A. Mehlenbacher and D.C. Smith.  2012.  Identification and mapping of DNA markers linked to eastern filbert blight resistance from OSU 408.040 hazelnut.  HortScience 47:570-573. 

Mehlenbacher, S.A., D.C. Smith and R. L. McCluskey.  2012.  'Eta' and 'Theta' hazelnut pollenizers.  HortScience 47:1180-1181. 

Sathuvalli, V.R. and S.A. Mehlenbacher.  2012.  Characterization of American hazelnut (Corylus americana) accessions and Corylus americana x Corylus avellana hybrids using microsatellite markers.  Genetic Resources and Crop Evolution 59:1055-1075.  DOI 10.1007/s10722-011-9743-0.

Chambers, U., V.M. Walton, and S.A. Mehlenbacher. 2011. Susceptibility of hazelnut cultivars to filbertworm, Cydia latiferreana. HortScience 46:1377-1380.

Sathuvalli, V. S.A. Mehlenbacher and D.C. Smith. 2011. DNA markers linked to eastern filbert blight resistance from a hazelnut selection from the Republic of Georgia. J. Amer. Soc. Hort. Sci. 136: 350 - 357.

Sathuvalli, V.R. and S.A. Mehlenbacher. 2011. A bacterial artificial chromosome library for ‘Jefferson’ hazelnut and identification of clones associated with eastern filbert blight resistance and pollen-stigma incompatibility. Genome DOI:10.1139/G11-048 .

Mehlenbacher, S.A., D.C. Smith and R.L. McCluskey. 2011. 'Jefferson' hazelnut. HortScience 46:662-664.

Mehlenbacher, S.A., D.C. Smith, R.L. McCluskey and M.M. Thompson. 2011. 'Tonda Pacifica' hazelnut. HortScience 46:505-508.

Mehlenbacher, S.A., D.C. Smith, and R.L. McCluskey. 2011. Hazelnut breeding at Oregon State University. Corylus & Co. (Rivista del Centro Studi e Ricerche sul Nocciolo e Castagno). No. 2, p. 6-15 (in English and Italian).

Sathuvalli, V.R., H.L. Chen, S.A. Mehlenbacher and D.C. Smith. 2010. DNA markers linked to eastern filbert blight resistance in 'Ratoli' hazelnut. Tree Genetics and Genomes 7:337-345. DOI: 10.1007/s11295-010-0335-5.

Sathuvalli, V. S.A. Mehlenbacher and D.C. Smith. 2010. Response of hazelnut accessions to greenhouse inoculation with Anisogramma anomala. HortScience 45:1116-1119.

Gürcan, K. and S.A. Mehlenbacher. 2010. Transferability of microsatellite markers in the Betulaceae. J. Amer. Soc. Hort. Sci. 135:159-173.

Gürcan, K. and S.A. Mehlenbacher. 2010. Development of microsatellite marker loci for European hazelnut (Corylus avellana L.) from ISSR fragments. Molecular Breeding 26:551–559. DOI 10.1007/s11032-010-9464-7

Gürcan, K., S.A. Mehlenbacher, R. Botta and P. Boccacci. 2010. Development, characterization, segregation, and mapping of microsatellite markers for European hazelnut (Corylus avellana L.) from enriched genomic libraries and usefulness in genetic diversity studies. Tree Genetics and Genomes 6:513-531. DOI: 10.1007/s11295-010-0269-y

Gürcan, K., S.A. Mehlenbacher and V. Erdogan. 2010. Genetic diversity in hazelnut cultivars from Black Sea countries assessed using SSR markers. Plant Breeding 129:422-434. DOI: 10.1111/j.1439-0523.2009.01753.x

Sathuvalli, V.R. and S.A. Mehlenbacher. 2010. Fine mapping of eastern filbert blight resistance in hazelnut with markers from BAC end sequences. ISHS Symposium on Molecular Markers in Horticulture, Corvallis, OR, July, 2009. Acta Hort. 859:395-400.

Mehlenbacher, S.A. and David C. Smith. 2009. 'Red Dragon' ornamental hazelnut. HortScience 44:843-844.

Mehlenbacher, S.A., D.C. Smith and R. McCluskey. 2009. 'Yamhill' hazelnut. HortScience 44:845-847.

Gökirmak, T., S.A. Mehlenbacher and N.V. Bassil. 2009. Characterization of European hazelnut (Corylus avellana) cultivars using SSR markers. Genetic Resources and Crop Evolution 56:147-172. (published online in 2008 as DOI 10.1007/s10722-008-9352-8).

Mehlenbacher, S. 2009. Genetic resources for hazelnut: state of the art and future perspectives. Acta Hort. 845:33-38.

Gürcan, K., S. Mehlenbacher and V. Cristofori. 2009. Inter-simple sequence repeat (ISSR) markers in hazelnut. Acta Hort. 845:159-162.

Mehlenbacher, S.A., D.C. Smith and R.L. McCluskey. 2008. 'Sacajawea' hazelnut. HortScience 43:255-257.

Mehlenbacher, S.A. 2008. Betulaceae – Corylus avellana – hazelnut. p. 161-172. In: Janick, J. and R.E. Paull (eds.). The encyclopedia of fruit and nuts. CAB International, Cambridge University Press, Cambridge, UK.

Molnar, T.J., D.E. Zaurov, J.C. Goffreda and S.A. Mehlenbacher. 2007. Survey of hazelnut germplasm from Russia and Crimea for response to eastern filbert blight. HortScience 42:51-56.

Mehlenbacher, S.A., A. N. Azarenko, D. C. Smith, and R. L. McCluskey. 2007. 'Santiam' hazelnut. HortScience 42:715-717.

Chen, H., S.A. Mehlenbacher and D.C. Smith. 2007. Hazelnut accessions provide new sources of resistance to eastern filbert blight. HortScience 42:466-469.

Mehlenbacher, S.A. 2007. Hazelnut breeding – an update from Oregon. Nucis Newsletter (FAO-CIHEAM) 14:9-10. (Dec. 2007).

Lunde, C.F., S.A. Mehlenbacher and D.C. Smith. 2006. Segregation for resistance to eastern filbert blight in progeny of 'Zimmerman' hazelnut. J. Amer. Soc. Hort. Sci. 131:731-737.

Mehlenbacher, S.A. and D.C. Smith. 2006. Self-compatible seedlings of the cutleaf hazelnut. HortScience 41:482-483.

Mehlenbacher, S.A., R.N. Brown, E.R. Nouhra, T. Gokirmak, N.V. Bassil and T.L. Kubisiak. 2006. A genetic linkage map for hazelnut (Corylus avellana L.) based on RAPD and SSR markers. Genome 49:122-133.