Spring 2011 Newsletter
'Jefferson' Genome Sequencing Concludes
The Hybrid Hazelnut Consortium continues progress toward its goal of creating climatically adapted, disease-resistant hazelnuts suitable as a sustainable crop for much of the U.S.
Researchers at Oregon State University have sequenced the genome of 'Jefferson' hazelnut and are assembling it. The sequence shows a high frequency of microsatellites and single nucleotide polymorphisms that will be useful in developing markers for use in research and applied breeding.
OSU researchers used 21 microsatellite markers to fingerprint 87 accessions of C. Americana and 69 hybrids. The hybrids include 40 from the Arbor Day Foundation (ADF) farm. The microsatellite marker data was used to construct a dendrogram to illustrate the genetic relationships among the accessions. The first group is of C. Americana 'Rush', European cultivars and 'Rush' x European hybrids. Most of the ADF and Rutter hybrids were placed in two groups, indicating a narrow genetic base for this material. However, the collection of C. Americana shows great diversity and indicates the importance of collecting and using as parents a wide assortment of American hazelnuts. OSU continues to make crosses with C. Americana in the collections in Corvallis. The Consortium is actively seeking additional representatives of the American hazel.
Rutgers is continuing work on Eastern Filbert Blight (EFB) genomics. Sequence data received from Illumina has been assembled. Scientists are screening the microsatellite markers, searching for those that might be useful.
Mapping of Incompatibility Markers Begins
Because hazelnuts are self-incompatible and many cultivars are cross-incompatible, it's necessary to include pollinizers in new plantings. Incompatibility is under simple genetic control-one locus (the S-locus) with 33 alleles. Lab-pollinated flowers and fluorescence microscopy are used to identify the alleles. In February, OSU researchers identified the alleles in 81 Turkish selections. Hybrid hazelnuts developed by the Consortium will be tested in a similar manner prior to their release. Work on map-based cloning of the S-locus will begin soon, and will clarify the molecular basis of incompatibility in hazelnuts. The information will be helpful in writing the next SCRI proposal (premliminary results from this summer will be included in the proposal, and the final work done with funds provided by the extension of the SCRI grant).
New Crosses Completed
Dr. Shawn Mehlenbacher at Oregon State University finished the latest round of crosses at the end of February, and hybrid seeds will be harvested in the fall. Included are American x European crosses for the Consortium's efforts.
Native Seed Lots Collected
Rutgers' Dr. Tom Molnar now has 28 different C. Americana seed lots, with more than 500 seedlings germinated this spring, as a result of Arbor Day Foundation's request to its members, and from the Northern Nut Growers Association. Half of the seeds have been shared with the Nebraska Forest Service for planting. Both groups will be evaluating the seedlings for EFB resistance, cold hardiness, nut quality, and kernel yield. At Rutgers, several of the top Arbor Day hybrid hazelnut selections have been crossed with elite pollen from Oregon State to generate a new crop of advanced-generation hybrids. Seeds from these crosses will be evaluated in New Jersey and shared with the Nebraska Forest Service in the fall for evaluation in Nebraska. Additional crosses made with EFB-resistant plants from Russia and Ukraine appear strong-growing, EFB-resistant, and high-yielding. A number of the best also have been crossed using elite OSU pollen, which will produce new genetic lines to study and potentially lead to new cultivars adapted to the eastern U.S.
Study of the Eastern Filbert Blight (EFB) Fungus Continues
New isolates of Anisogramma anomala, the fungus that causes EFB, are being collected from around the U.S. and Canada. To date, 15 new isolates have been gathered from locations around the eastern U.S, including sites in Michigan and Wisconsin, in addition to about 30 collected previously. These new isolates will be grown in the lab for DNA extraction and will be included in a genetic diversity study to better understand the unique pathogen. Of particular interest is the EFB collected from wild groves of native Corylus Americana in Wisconsin by Clayton Leadbetter (Rutgers) and Kelsey Brasseur (University of Wisconsin). Researchers are interested in learning how the diversity of A. anomala in the wild compares to that of isolates collected from susceptible European hazelnuts and hybrid hazelnuts grown in horticultural settings across North America.
This spring, Rutgers scientists are using a real-time PCR-based test they developed to detect A. anomala from plant tissues, to identify susceptible seedlings at a very early stage, many months earlier than previous EFB detection methods. This technique should allow breeders to determine whether a seedling is infected with EFB, thus susceptible, very soon after it is inoculated (this process normally takes 16-20 months). If proven effective, this technique will allow breeders to be much more efficient in their disease screening processes and will provide a means to focus attention and resources on plants identified at an early stage as very likely to be resistant. Overall this means more resistant plants will go to the field to be evaluated for cold hardiness, kernel yield, kernel quality, pest resistance, etc.
Nut, Kernel Analysis is Under Way
The Industrial Agricultural Products Center (IAPC) at the University of Nebraskaâ€“Lincoln has evaluated six varieties of 2010 hybrid hazelnuts from Oregon State University and four varieties from the Nebraska Forest Service. The evaluation included nut and kernel analysis to determine kernel and oil content.
High Oil Content
The percent oil content is consistently high in both the OSU hazelnut varieties (C. avellana) and the hybrid hazelnut crosses. The range of percent oil content for the hybrids is much broader, from 51.4% to 75.1%, compared to those from OSU which ranged from 62.5% to 68.4%.
The data from this evaluation will be compared to 2009 and 2011 production. Oil quality characteristics also are being studied, and hazelnut shells are being evaluated for phenolic compounds and natural antioxidants for possible byproduct use. Hazelnut shells and husks previously were evaluated for energy (Btu) potential and density when formed into basic pellets.
Planting Begins at Nebraska Site
Nebraska Forest Service (NFS) has begun planting approxi-mately 1,200 hazelnut seedlings in 3-ft. spacings in the new six-acre plot at Horning Farm State Demonstration Forest. NFS will plant up to 100 seedlings of each cross received from Rutgers and Oregon State; Arbor Day Foundation will receive any extra plants. These plants are crosses developed at both Rutgers and Oregon State. They will be assessed in Nebraska for EFB resistance and climatic adaptation. NFS continues to expand the planting area for hazelnuts, preparing an additional two acres for eventual hazelnut tests.
Troy Pabst of NFS reported that flower phenology was very rapid this year at NFS sites, with about two weeks from red dot to finish. Flower phenology also is being tracked on select plants at Arbor Day Farm.
Stink Bug Infestation Affects N.J. Crops
Rutgers scientists are monitoring the high infestation of brown marmorated stink bugs in New Jersey. Many of Rutgers' hazelnut seeds failed to germinate, even from good parent plants that were used previously. The infestation of the exotic pest is a potentially serious problem for hazelnuts and other crops in New Jersey. Dr. Tom Molnar says hazelnut damage occurs when the bugs feed on the kernel before the shell is hard. When mature, the nutshell is normal, but the kernel inside is cracked with visible feeding marks. The bugs are not laying eggs in the nuts so no quarantine measures are needed at this time. Scientists are unsure about what triggered the huge outbreak in New Jersey. Oregon entomologists are monitoring for a similar outbreak there, Dr. Shawn Mehlenbacher said, but have not seen it to date.
Outreach Strategy Developed
Nebraska Forest Service and Arbor Day Foundation Consortium members met in April to formulate an outreach plan for the remaining two years of the current CREES grant. The group outlined plans for continued communication through news-letters, fact sheets, talking points, video, a blog, speaking engagements, Congressional visits, and the Consortium website.
Outreach to various audiences continued in the first quarter of this year: