Performing Department
(N/A)
Non Technical Summary
Hazelnut breeding efforts in the eastern U.S. have been led by Rutgers University in collaboration with OSU for over 25 years with more recent collaboration with the Hybrid Hazelnut Consortium partners that include the Universities of Missouri and Nebraska and the Arbor Day Foundation. From these efforts new eastern-adapted cultivar releases are opening new, large regions to cultivation, positioning the U.S. to become a global leader in the hazelnut industry.The primary limiting factor to hazelnut production in North America is the stem canker disease EFB; the cultivated European hazelnut, Corylus avellana, is in general highly susceptible to the causal fungal pathogen, Anisogramma anomala, where systemic perennial canker spread leads to fatal stem dieback.Selection within the breeding programs occurunder high EFB pressure and seeks to identify eastern-adapted individuals expressing EFB-resistance and the high kernel quality expected by markets, which includes round kernels free from defects that are 10-12 mm in diameter, a pellicle that removes easily after roasting,and excellent flavor that supports fresh markets as well as roasted kernels, which are used in various confectionary products.The first set of cultivars meeting these goals have been released, including C. avellana 'Raritan', C. avellana 'Somerset', and C. avellana × C. americana 'OSU 541.147' "The Beast". However, challenges regarding the release of long juvenility crops like hazelnutallowed for major gaps in the current slate of cultivars available from nurseries.Additional cultivars are urgently needed to add climate and regional resiliency to the new eastern orchards, including a much more substantial and compatible pollen cloud. Fortunately, a deep pipeline of late-stage breeding selections now exists and has been established in Missouri and New Jersey. Their final evaluation and subsequent release are expected to drive: 1) expansion of the cultivation range of hazelnut, while 2) diversifying resistance to EFB, and 3) providing production cultivars and pollinizers with cold hardy catkins, appropriate bloom phenology, and self-incompatibility (S) alleles that are widely cultivar compatible. The overriding goal of this proposed project is to expedite the delivery of diverse, regionally adapted sets of high-yielding hazelnut cultivars that have excellent kernel quality, meeting confectionary market standards, by: 1) coordinating and bolstering replicated trial evaluations and concurrently; 2) priming the nursery supply chain with commercial scale layer beds that shorten the timeline from selection trialing to commercial scale planting; and 3) providing outreach opportunities and materials to guide adoption. Dedicated breeding programs afford the opportunity to add resiliency to developing industries through strategic germplasm diversificationand in this instancewill bring a new high-value, low-input perennial crop option to growers across a broad geography in the eastern U.S.
Animal Health Component
0%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
The overriding goal of this proposed project is to expedite the delivery of diverse, regionally adapted sets of high-yielding hazelnut cultivars that have excellent kernel quality, meeting confectionary market standards, by: 1) coordinating and bolstering replicated trial evaluations while concurrently; 2) priming the nursery supply chain with commercial scale layer beds that shorten the timeline from selection trialing to commercial scale planting; and 3) providing outreach opportunities and materials to guide adoption. The reliance of horticultural industries on a limited set of clonal cultivars, for example banana ('Cavendish') and U.S. pistachio ('Kerman'), is all too common despite representing a major liability to abiotic and biotic stress and/or market changes. Dedicated breeding programs afford the opportunity to add resiliency to developing industries through strategic germplasm diversification.In the case of the U.S. hazelnut industry, the need for diversification takes several forms. Foremost, diversification of sources of EFB-resistance in cultivation, especially beyond that of 'Gasaway', on which Oregon's industry is almost completely based [3], to lessen selective pressure and maintain longevity of resistance sources over the >35+ year productive lifespan of orchards. Further, geographically distinct regions distribute the vulnerability of U.S. supply to potential major disturbances. Across multiple regions of the eastern U.S., new hazelnut orchards are being established with significant plans for near-term expansion as demonstrated by our support letters and records of tree sales from nurseries. To increase their resiliency and reduce the over-planting of a narrow set of currently available cultivars, action is needed. The emerging industry requires additional production cultivars and dedicated pollinizers with cold hardy catkins that have S-alleles compatible with existing cultivars and matching bloom phenology. Fortunately, and the reason we are writing this proposal now, is we are confident the necessary plants to meet these industry needs exist in our advanced breeding selections that have been established in replicated trials in New Jersey and Missouri. Expediting their delivery to growers will support successful industry development. In addition to plant selection, a focal challenge in hazelnut cultivar "delivery" is decreasing the time lag to scale new releases within the nursery trade. In vitro micropropagation is a common and relatively recent efficient strategy used for hazelnut, but culture establishment and multiplication can take years (with some clones being recalcitrant) [11-14], which increases the expense, limiting the number of selections that can enter this phase, and greatly delays the availability of commercial-scale supplies. Although somewhat labor intensive, traditional mound layering, similar to what is done for clonal apple rootstocks, is consistently effective and scalable. By the early initiation of sizeable clonal layer beds with several or more licensees in strategic regions, it is possible to expedite the propagation of many tens of thousands of trees of a wider set of cultivars since layering has a lower bar to entry than tissue culture. Further, by working with multiple nurseries in dispersed regions, it is possible to de-centralize and diversify production of trees (right now a majority originate in Oregon and are shipped East), which buffers production from any one particular failure, and can reduce shipping costs for trees. The ability to realize these goals depends on support to build program capacity and continuity for replicated trial management and depth of evaluations with subsequent in-house propagation to generate propagules for scaling. Accordingly, the proposed project's Supporting Objectives include:Evaluating over 80 advanced breeding selections of diverse pedigrees and EFB-sources in established replicated trials, compared to commercial standards, in New Jersey and Missouri.Documenting S-alleles of breeding selections to support decisions on release of complementary production cultivars and dedicated pollinizers; completing an S-allele living library at Rutgers and building in-house capacity to identify S-alleles.Enhancing and securing the availability of cultivars in the marketplace by facilitating the establishment of clonal layering beds of new releases at six or more licensed nurseries, where propagation capacity can exceed 10,000 layers annually per nursery.Extending hazelnut production knowledge by holding workshops and developing grower guides across multiple medias to support nursery production and informed adoption of new cultivar mixes with diverse EFB-sources and compatible pollinizers by region.
Project Methods
Objective 1: Identify new cultivars for release from multi-location replicated trials. The trials follow a randomized complete block design with a minimum of four blocks (one clone/genotype/block) and include a diverse set of >80 advanced selectionsthat were established in New Franklin, MO, and New Brunswick, NJ. The selections are from the Rutgers and OSU breeding programs and represent diverse sources of EFB resistancepropagated by mound layering. The F1 C. americana × C. avellana selections result from controlled crosses by OSU and Rutgers and are the most diverse representation of C. americana used in breeding to-date, 38 accessions from 15 states.Evaluation methods for 1.1 to 1.4 follow Mehlenbacher [2023] . In 1.1 to 1.3, an Analysis of Variance (ANOVA) will test for significant genotype, environment, and genotype by environment effects, followed by mean separation via Fisher's LSD.?Evaluate breeding selections for nut quality and yield consistency.In-shell nut yield will be measured directly by harvesting and measuring nut mass per tree. Nuts drop to the ground over a 2-3-week period in Aug/Sept and will be harvested on a 2-3-day interval to minimize predation using handheld tools.Husk morphology will be recorded.Per tree, the portion of the crop that falls free from the husks will be harvested, dried, and weighed separately from the portion of the crop that remains attached to the involucre when it falls. Husk-attached nuts will be threshed manually. One-hundred nuts (r=2, n=50) support quality evaluations. Individually, nut mass, kernel mass, kernel diameter, pellicle removal, and nut/kernel defects (%) will be measured. Kernel percentage is measured by dividing kernel mass and nut mass, and kernel diameter is measured in both the x- and y-axis with a digital caliper. Pellicle removal, or blanching, is evaluated on a qualitative scale after roasting from 1 to 7. The kernel defects assessed includeblank nuts, mold, shrivels, poor fill, twins, black tips, and brown stain. Following roasting and blanching, kernels will be qualitatively sampled for flavor. Sampling seeks a crisp and nutty aroma absent of off characters (e.g., chalkiness, rancidity), and several cultivars serve as consensus global-standards for "outstanding-flavor", including 'Tonda Gentile delle Langhe', 'Tonda di Giffoni', and 'Tombul', along with OSU cultivar releases 'Sacajawea', 'McDonald' and 'Polly O'. Outstanding selections will be shared with confectioners for industry quality and processing testing.Record pistillate and catkin bloom phenology.Pollen shed, pistillate flower emergence, and vegetative budbreak will be documented yearly per region, as done by Capik and Molnar [37]. Julian date will be recorded per the following stages via regular scouting and observation in the plot, every 2 to 3 days weekly, from late December through mid-April. Catkin pollen shed occurs in three Stages. Catkin elongation is initiated at Stage 1, where stretching initiates to signify a break in dormancy and the beginning of minor pollen shed. Stage 2 describes catkins that are fully elongated and brightly yellow with significant pollen shed (pollen release is visible), which is considered peak shed. Peak pollen shed concludes at Stage 3, where anthers within catkins appear dry and withered, despite minute amounts of pollen shed releasing for several more days. Catkin damage due to winter injury will be noted, where low temperature results in a clear change in color from a vibrant yellow to a brown.Pistillate flower development will be documented using four stages, which we note are not absolute but capture the major sequences of bloom [37]. Phenology ratings will be taken on female flowers present on typical, mature branches at three time points: 1) first incidence, 2) peak, where 50% of flowers reach the stage, and 3) last incidence. Stage 1 is represented by a single ''dot'' of red or purple color emerging from the center of the floral buds. Style emergence from the floral buds signifies Stage 2. The individual styles point straight out at this stage and have only just begun to separate. Stage 3 occurs when the styles are fully exserted and begin to bend away from the center. We note that stigmas are receptive to pollen at all stages of exertion [42].Final pollinizer determination will be supported by S-allele data produced in Objective 2.Objective 2: Identify S-alleles of candidate releases and breeding parents.S-alleles of candidate releases and parents will be identified through direct pollinations of pistillate flowers with tester pollens and subsequent fluorescent microscopy. If parents' S-alleles are known, only those four S-alleles will be tested. In years 1 and 2, identification will occur primarily at OSU (25+ selections per year).In years two and three, S-alleles will be typed at Rutgers in selections remaining under evaluation following protocols of Mehlenbacher [59], where alleles are determined by observing the result of pollination with 33 pollen testers (pollen shared from OSU of tester plants not available at Rutgers). Selections have branches identified in December in advance of bloom for emasculation. The catkins are clipped off, and Tyvek bags are placed over the branches to exclude pollen. Later, when the female flowers are receptive on respective genotypes, the Tyvek bags are removed, and female buds are harvested using forceps and placed into a petri dish on moist filter paper for lab testing. Pollen is collected from the 33-tester genotypes in advance, which each express just one respective S-allele. Catkins are set out on white paper overnight, and the anthers dehisce as they dry, shedding pollen. Pollen is collected and stored in a glass vial at -18° C. Pollen is administered to the styleswith excess shaken off. Pollinations are performed in the afternoon, and 16-hours later microscope slides are prepared for imaging of the pollination interaction. Preparation involves plucking styles with forceps and spreading them on a glass slide with a drop of aniline blue dye. A flexible cover slip is then used to cover and squash the sample, and the sample is inspected with a fluorescence microscope.Objective 3: Establish mound layering beds for new cultivar releases at Rutgers, Missouri, and up to six licensed nurseries.Mound layering is a simple process, in brief: when current year's basal sprouts are about pencil width in diameter (June), hog ring staples are applied to the base. IBA rooting hormone (1000 ppm) is applied to the shoot six inches above the staple. Moist sawdust is then mounded around the basal sprouts to a depth of about eight inches. Adequate moisture is maintained in the sawdust mound to promote and support root growth. In November, layer harvest can begin by carefully removing the mound to expose the roots. The shoots can be clipped below the hog ring, where the basal sprouts have been girdled. Stock layering bedswill be completed at Rutgers and established at the University of Missouri in two phases: 1) immediately for eight high-probability nut production releases and 2) beginning after the second growing season for the remainder of genotypes under evaluation. The goal stock bed size at each university is 20-25 per genotype. Rutgers currently has four stock beds established for each genotype that is in the replicated trial, and these beds will be layered for chosen genotypes towards the end of project year two, with a production capacity of 40 to 60 per genotype per year.We anticipate up to 30 genotypes will be transferred to nurseries, between production cultivars and pollinizers, of which between 15 to 20 genotypes will ultimately be released as new cultivars for public sale. Licensing and public sale will occur promptly upon patent filing starting in the end fall of project year four.Around 100 layers will be provided per genotype to each nursery.