- About Us
PI: Shawn Mehlenbacher, Professor, Hazelnut Breeding and Genetics
Hazelnut is categorized in the Corylus genus; there are 15 species in the genus, but Corylus avellana is the species of commercial importance. The plant is a large shrub native to the Nothern Hemisphere, but when managed as they are in orchard situations, they grow like trees. Hazelnuts are distinctive from other orchard crops because they are monoecious, anemophilous (wind pollinated), and bloom in midwinter (December to March in the Northern Hemisphere). Each catkin produces between 4 million to 40 million pollen grains, however, plants generally demonstate sporophytic incompatibility. The staminate and pistiallate flowering times may not overlap, and cultivars can be either protogynous or protandrous. Therefore cross-pollination with compatible pollininers that shed pollen when female flowers are receptive is required for optimal nut production.
Research and Extension
Dr. Mehlenbacher regularly gives presentations to Oregon's hazelnut growers at the annual meeting and summer tour of the Nut Growers Society of Oregon, Washington, and British Columbia. He reports research results to the Oregon Hazelnut Commission. The Arbor Day Foundation takes the lead in outreach by the Hybrid Hazelnut Consortium (http://www.arborday.org/programs/hazelnuts/consortium/).
Dr. Mehlenbacher has no formal Extension appointment, but with the passing of Jeff Olsen and expansion of hazelnut plantings in the valley, he and his two research assistants have been receiving an increased number of questions. In 2014 he hosted the annual meeting of the Northern Nut Growers Society in Corvallis and was elected to its Board of Governors.
Publications since 2005
Sathuvalli, V.R., S.A. Mehlenbacher. 2015. Genes expressed following compatible and incompatible pollinations in hazelnut (in preparation).
Sathuvalli, V.R., S.A. Mehlenbacher and T.C. Mockler. 2015. Annotation of whole BAC sequences in the eastern filbert blight resistance region from 'Jefferson' hazelnut (Corylus avellana L.). (in preparation).
Colburn, B.C., S.A. Mehlenbacher and V.R. Sathuvalli. 2015. 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. 2015. Novel sources of eastern filbert blight resistance in hazelnut accessions 'Culpla', 'Crvenje' and OSU 495.072. HortScience 49 (in press).
Sathuvalli, V.R. and S.A. Mehlenbacher. 2015. 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.