Black Walnut Crop Production for Uses in Northern Climates

BLACK WALNUT CROP PRODUCTION FOR USES IN NORTHERN CLIMATES

Sponsoring Institution

National Institute of Food and Agriculture

Project Status

ACTIVE

Funding Source

AFRI COMPETITIVE GRANT

Reporting Frequency

Annual

Accession No.

1030443

Grant No.

2023-67013-39512

Cumulative Award Amt.

$92,388.00

Proposal No.

2022-10987

Multistate No.

(N/A)

Project Start Date

Aug 15, 2023

Project End Date

Aug 14, 2025

Grant Year

2023

Program Code

[A1152]- Physiology of Agricultural Plants

Recipient Organization
UNIV OF MINNESOTA
(N/A)
ST PAUL,MN 55108

Performing Department
(N/A)

Non Technical Summary
Black walnut (Juglans nigra) is a long-lived perennial tree that could be cultivated and utilized more broadly throughout the northern United States. Aside from its value as a quality timber crop, this species offers edible nuts and can be tapped for syrup production, among other uses and byproducts. Whereas most woody perennial cropping systems take place throughout the regions of the United States with more mild climates, black walnut has potential for use in cold climates. However, little information exists that is pertinent to its cultivation and application under northern conditions. Physiological evaluation and product-driven research could generate novel foundational scientific insights as well as drive new opportunities for stakeholders throughout multiple realms of agriculture and related industries.This project aims to inform the development of black walnut crops and products by evaluatingsap flow of cultivated trees, characterizing consumer preferences of syrups and nuts, as well as studying genetic variation within this species.

Animal Health Component

80%

Research Effort Categories

Basic

20%

Applied

80%

Developmental

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
125	1213	1020	80%
202	1213	1080	10%
502	1213	1020	10%

Knowledge Area
125 - Agroforestry; 202 - Plant Genetic Resources; 502 - New and Improved Food Products;

Subject Of Investigation
1213 - Walnut;

Field Of Science
1080 - Genetics; 1020 - Physiology;

Keywords

Goals / Objectives
This seed grant proposal presents four objectives designed to use a systems approach for collecting data, plans to uncover foundational information pertinent to plant physiology and plant production, and supports long-term intention of informing a subsequentproposal. The research team aims to characterize sap flow peaks, intensity, and duration, to understand the potential market (consumer survey) for black walnut and its products, conduct consumer/industry sensory evaluation panels to detect syrup and nut flavor differences among select black walnut genotypes, and perform genetic testing of a wide sample of genotypes to determine the genetic diversity within and among locations and populations. The seed grant will culminate with Extension / stakeholder events to aid in achieving the objectives as well as communicating the opportunities for this specialty crop to northern growers and consumers.

Project Methods
1.Sap FlowFive 3-N Sap Flow Sensors (East 30 Sensors, Pullman, WA) will be installed on separate, mature, healthy trees at the UMN Horticultural Research Center. Sensors will track sap flow throughout the dormant period and growing season. Data will be extracted, formatted, and grouped using time as a factor. Data will be analyzed first to determine when sap flows throughout the year to consider whether multiple runs of sap are possible. Next, major flow periods will be compared to determine which is best suited to harvest for sugarmaking in a northern climate.The following year, this process will be repeated and based on these combined datasets (years 1 and 2), neighboring trees will be tapped at optimal peaks of sap flow. Standard metrics of evaluation (brix) will be used on sap harvested during these times to determine what characteristics, if any, change between runs.2.Consumer SurveyTo procure a sample of participants, we will purchase a sample of 200 consumer participants across the country. Colleagues from Missouri, West Virginia, and New York (regions with a significant black walnut presence) will be asked to encourage their stakeholders to participate in the survey above and beyond the minimum sample of 200 participants.A series of survey questions will be created. This survey will be used to identify stakeholder knowledge of black walnuts, food products, and preferences or prejudices connected with the crop.All recruiting and experimental procedures will be subject to the Institutional Review Board (IRB) at the University of Minnesota. Drs. Miller and Anderson will be responsible for executing the survey, collecting responses, and writing a report to summarize findings. Team members will collaboratively work to write a report to convey survey findings.3. Sensory Evaluation PanelsThe sensory evaluation(s) will take place at the University of Minnesota. The sensory evaluation will compare black walnut syrup and nuts to comparison products (maple syrup and English walnuts, respectively). The intention of this evaluation is to characterize consumer preferences; the information will drive further research directions. The success of this activity will be determined by the completion of a written report of sensory evaluation findings and the number of attendees of the field day tour and demonstration.Black walnut syrups and nuts will be evaluated in one or more panels of sensory evaluations of primarily untrained evaluators (spanning different age groups and gender). Where possible, the nuts will be collected and processed from specific trees (genotypes) used in the molecular analyses to provide sensory data to couple with genetic information.For all sensory sessions, multiple black walnut syrups and nuts will be tested, randomized and assigned alphanumeric codes. A specific number of codes will then be randomly assigned to each person's seat, avoiding duplication. Each seat will also have one or more commercial syrup, nut, or nut butter standards for comparisons to provide additional genetic diversity for testing panelist palettes (Anderson, et al., 2020; Kostick et al., 2017; Yue et al., 2020). A total of seven samples per panelist is the standard sample size to avoid exhaustion (Nikolaevich et al., 2015). For statistical purposes, sensory panels will be complete blocks and individual panelists will be incomplete blocks.Syrup sensory panel setups will consist of labeled glass vials with caps for individual, numbered samples of 5-15 ml/vial (Camara, et al., 2019). Each test (blind tasting, olfactory) will be done in triplicate, per standard sensory panel setups. Panelists will taste and smell each sample after uncapping it and record their values. Sample setup was for directly smelling and tasting syrup from a vial or pouring the syrup into a neutral colored (opaque) 7.62 cm (3") plastic taster spoon (disposable, odor-free; Culetu, et al., 2014). Samples will be placed at their corresponding seats along with one instruction (cf. Fig. 1, Kostick, et al., 2017) and seven evaluation sheets (cf. Fig. 2, Kostick, et al., 2017), one color reference card, one neutral white and unlined (7.62 x 12.7 cm; 3" x 5") card, water cup, spit cup, and unsalted crackers (cf. Fig. 3, Kostick, et al., 2017; Halat et al., 1997). All sensory evaluation panels will be conducted at room temperature to match the predominant conditions for syrup consumption and conditions for previous panels (Anderson, et al., 2020; Camara et al., 2019; Kostick et al., 2017; Yue et al., 2020).Black walnut "nut" sensory evaluations will include a control (English walnuts) and several samples of black walnuts. Each panelist will receive a cup of nuts (~5g/sample) for testing; the remainder of the experiment setup will follow the procedural outline for syrups. For nut butter sensory evaluations, panelists will receive an opaque cup of nut butter (~5 g/sample) for tasting in a similar manner.Each group will be given an oral introduction on how to taste syrups and nuts, palette cleansing procedures, use of the color chart (cf. Fig. 3, Kostick, et al., 2017) and a review of the instruction and evaluation sheets. A modification of the standard Hedonic 9-point (Lawless and Heymann, 2010) to 7-point scale (Gruji, et al., 2007) will be implemented with an unnumbered scalar range of seven boxes for recording scores (cf. Fig. 2, Kostick, et al., 2017). All members of each group will taste-test the first sample (control) together using the instructions and, once they have recorded their evaluative assessments of the control, discuss the potential data points for each of the ten factors for each syrup, nut, or nut butter (Camara et al., 2019). Syrups and nuts will be evaluated separately. Panelists will be provided with adequate space to evaluate their samples.Sensory characteristics marked in the linear box plots will be transformed into quantitative data points, based on measuring (mm) from the beginning (far left-hand side) of the scale to wherever the panelist made their mark (Anderson, et al., 2020; Kostick et al., 2017; Yue et al., 2020). This value will then be divided by the total length of the scale and then multiplied by ten for data points on a ten-point scale.To determine variant groups responsible for the sensory panel traits, multivariate analyses will be performed using principal component analyses (PCA) using the SPSS CATPCA procedure. Qualitative data, specifically the desire to purchase, will be analyzed using a Chi-square test with equal distribution across the two classes (1:1 Chi-square; df=1). The Chi-square correction of (Observed-Expected-0.5)2will be used. Pearson's Rank Correlations will be determined among variables.4. Genetic TestingSNP generation will be optimized for black walnut with the pilot plate of samples, representing the diversity of the species' genome. The black walnut SNP data would be used to determine genetic variation within/among populations and the number of genetic groups in the preliminary study.The purpose of this research is to conduct a preliminary molecular analysis of the genetic variation in a small subsample of black walnut populations to use as directives for the future SCRI grant proposal. A pilot plate with extracted DNA samples of 92 walnut tree genotypes and relatedJuglansspp. will be submitted to Diversity Arrays Technology for analysis. Single nucleotide polymorphisms (SNPs) of nuclear DNA will be determined using DArTseqLD, which should generate as many as 5,000-10,000 SNPs, some of which may be uniquely linked with phenotypic traits. DArTseq is widely used in polyploid species and those without any sequenced genome or classical genetic maps.A sub-sample of four provenances within the native range of black walnut will serve to characterize a small portion of the genetic diversity within this species.

Progress 08/15/23 to 08/14/24

Outputs
Target Audience:During this reporting period, we focused on several distinct target audiences that represent key stakeholders in the black walnut syrup project. Horticultural Science Professionals and Researchers: Activity: Presentation at the ASHS Northern Region 2024 Meeting Description: This audience included faculty, graduate students, extension specialists, and industry professionals engaged in horticultural science. Why? Targeting this group was essential because they play a crucial role in advancing research, supporting agricultural innovations, and developing sustainable practices that benefit growers and consumers in the Northern region, the same region for which this project was designed. By presenting at the ASHS Northern Region meeting, we shared knowledge that can inform and inspire further studies, collaborations, and educational efforts that align with the project's goals of expanding black walnut production as a viable specialty crop in northern climates. Engaging with these experts also helps establish credibility and strengthens the research foundation for future funding and development initiatives. General Public Activity: Black Walnut Grove Field Day during Maple Fest - Minnesota Arboretum. Description: Attendees at Maple Fest included families, children, and individuals interested in nature and local agriculture. Why? Engaging this group allowed us to foster community awareness of black walnut as a food crop with potential for exploration and growth in the northern region. Maple Syrup Producers and Industry Stakeholders: Activities: Presentation at the Minnesota Maple Syrup Producers Association Meeting; Extension Article in Minnesota Maple News Magazine. Description: This audience included maple syrup producers, enthusiasts, and industry stakeholders within Minnesota and surrounding areas. Why? Sharing our research with maple syrup producers and industry stakeholders provides them with insights into black walnut syrup as an innovative product that could diversify their offerings. By exploring this new syrup, producers can expand their product lines, appeal to a broader range of consumers seeking unique, locally-produced syrups, and increase their resilience in changing markets. This engagement encourages these experienced producers to consider black walnut as a valuable addition to their operations, potentially supporting the growth of black walnut syrup as a viable specialty crop in northern regions. Black Walnut Syrup and nut Consumers: Activities: Consumer Taste Panel for black walnuts, and black walnut syrup. Description: We engaged potential consumers with diverse backgrounds and taste preferences to assess their responses to black walnut syrup and nuts. This demographic includes individuals interested in artisanal and unique food products, making them a key audience for understanding market demand and preferences. Why? Engaging black walnut syrup and nut consumers is crucial for gauging initial interest, understanding flavor preferences, and assessing the purchasing potential for these unique products. This audience provides direct feedback on sensory qualities and appeal, which helps shape product development to align with market expectations. By understanding what consumers value most, we can provide producers with targeted recommendations that enhance product appeal, support market expansion, and foster the growth of black walnut products. Plant Biology Researchers and Students: Activity: Poster Presentation at Plant Biology 2024 Description: This audience includes scientists, researchers, and students specializing in plant biology, physiology, and genetics. Why?: By engaging with this audience, we shared knowledge that can inspire further studies, foster interdisciplinary collaborations, and strengthen the research foundation for sustainable black walnut cultivation. This interaction aligns with our project's goals of building a solid scientific base to support black walnut as a specialty crop. NIFA Project Directors and Extension Specialists: Activity: Presentation at NIFA's A1103/A1152 Project Directors Meeting Description: The audience included project directors, co-project directors, and key personnel involved in NIFA-funded projects under priority areas A1103 and A1152. Why? By presenting our findings to other NIFA project directors and Extension specialists, we shared valuable insights that align with national goals for specialty crop production and sustainable agriculture. This engagement also fosters networking opportunities and potential collaborations that can support our project's long-term impact and alignment with NIFA's strategic priorities. Arboretum Members, Gardening Enthusiasts, and Environmental Supporters: Activity: Article Publication in the Arboretum Magazine Description: The Arboretum magazine is designed for a diverse audience that includes members, visitors, and supporters of the Minnesota Landscape Arboretum, as well as gardening enthusiasts, nature lovers, and individuals interested in horticulture, conservation, and environmental sustainability. The readership typically includes Arboretum members, donors, volunteers, and local community members who are passionate about plants, landscaping, and natural beauty. Why? Targeting this audience is essential because they are naturally inclined to support and promote sustainable agricultural practices and local biodiversity. By engaging with this group through the Arboretum magazine, we increase public awareness of black walnut as a specialty crop, inspiring interest in sustainable production and conservation efforts. Their enthusiasm for nature and local agriculture aligns with our goal of building community support for black walnut cultivation and promoting it as a valuable addition to regional biodiversity and sustainability. Minnesota Landscape Arboretum Staff: Activity: Presentation at the Arb All Staff Meeting Description: This audience, which includes staff across various departments, provides internal support and understanding of our project. Engaging Arboretum staff helps ensure alignment with institutional goals and enhances the project's visibility among stakeholders who can aid in educational outreach and operational support. Why? Targeting Arboretum staff is strategic because their support and understanding can significantly amplify the project's impact. By involving staff across departments, we foster collaboration, ensure that the project aligns with the Arboretum's mission, and leverage internal resources to enhance outreach efforts. This engagement strengthens the foundation for educational programming and community involvement, crucial for promoting black walnut as a specialty crop. Changes/Problems:In the proposed project, our original plan was to have sap flow sensors installed by the end of Fall 2023 to begin monitoring sap flow in alignment with the tapping season and environmental variables. However, due to unforeseen circumstances, the company we initially partnered with encountered operational issues, preventing us from obtaining and installing the sensors as scheduled. This resulted in a delay in the installation process. To mitigate the impact of this delay and ensure we could still collect meaningful data during the critical tapping season, we adapted our approach. From January 31 to March 31, 2024, we manually measured sap flow by collecting the sap produced by each tree on a daily basis. While this method allowed us to capture sap flow data during the peak tapping season, it was more labor-intensive and less precise than the automated sensor system we had originally intended to use. In Spring 2024, we successfully secured sap flow sensors from a different supplier, and the installation was completed. Since then, the sensors have been continuously monitoring sap flow in 10 selected trees, allowing us to collect high-frequency data at 30-minute intervals. This data will complement the manually collected sap measurements and provide valuable insights for the remainder of the project. This change in approach delayed our ability to gather automated data but did not significantly impact the overall research schedule. We have adjusted our timeline accordingly to ensure that the key research objectives will still be met within the project period. What opportunities for training and professional development has the project provided?This project provided meaningful training and professional development opportunities for all involved. One undergraduate student received one-on-one mentoring, gaining hands-on experience in planning the black walnut taste panel. This mentorship covered the rationale behind the panel's design and methodology, fostering a deeper understanding of sensory evaluation techniques and the importance of structured data collection in consumer research. Additionally, the student gained insights into the unique flavor attributes of black walnut products and their potential market implications, broadening their knowledge of food science and research methods. This personalized guidance enhanced the student's practical skills and understanding of scientific approaches in real-world applications, laying a foundation for future professional development in the field. The research team also consulted with two distinguished experts to further refine the project's methodology: Dr. Zata Vickers provided guidance on consumer taste panel methodology and best practices before conducting the black walnut syrup and nut taste panels. Her expertise helped ensure that the team applied reliable, scientifically sound methods, and her feedback was instrumental in reviewing and refining the methodology. Dr. Chengyan Yue, with extensive experience in survey design, met with the team prior to launching the online consumer survey, ensuring a robust survey design that aligned with best practices for data reliability and validity. These expert consultations, combined with direct mentoring, allowed team members and the student to gain proficiency in sensory evaluation and survey methodology, enhancing the project's quality and supporting their growth in applied research skills. How have the results been disseminated to communities of interest?Extension and Community Engagement Events Black walnut groove tours during Maple Fest(March 2024) at the University of Minnesota Horticultural Research Center (HRC). This event was open to the public and featured guided sessions in the black walnut grove, attended by approximately 97 participants over three sessions. We demonstrated sap tapping techniques, discussed syrup production from black walnut trees, and presented early research findings on sap flow and syrup yield. This hands-on approach allowed participants, many of whom had no prior exposure to black walnut syrup production, to interact with the research team, ask questions, and experience the process firsthand. In addition, we hosted a booth at the Minnesota Arboretum during Maple Fest, which attracted over 200 visitors. The booth featured tri-folds and other educational materials on black walnut syrup production and curiosities about the species. The booth's goal was to raise awareness among general audiences. Presentations at Professional Meetings and Conferences: We have actively presented our research findings to both academic and practitioner audiences, helping bridge the gap between researchers and the public. Some of the key presentations include: Northern Region ASHS 2024 Meeting: Presentation titled "Optimizing Opportunities with Black Walnut in Northern Climates: Understanding Sap Flow Patterns and Syrup-making Potential." The audience consisted of students, researchers, and industry professionals interested in horticultural innovations. Minnesota Maple Syrup Producers Association (MMSPA) Meeting (May 2024): During this event, we presented the black walnut syrup project to local maple syrup producers, a community with significant overlap in terms of syrup-making interest but who may not be aware of black walnut syrup production. This presentation aimed to increase awareness of alternative syrup products among producers and encourage them to consider black walnut syrup as an additional revenue stream. Plant Biology ASPB 2024: We presented a poster titled "Sap Yield and Syrup-making Potential of Black Walnut (Juglans nigra L.) Trees in Northern Climates." This event helped reach a broader scientific community, fostering conversations that could extend beyond agricultural research into plant biology and ecosystem services. Educational materials and publications We created two informational trifolds, one focused on "How to Tap and Make Black Walnut Syrup" and the other on "Black Walnuts in Minnesota: Facts and Curiosities." These trifolds were distributed to over 100 individuals at various events, including Maple Fest and the Minnesota Landscape Arboretum. These educational materials were designed to be accessible and engaging, presenting scientific concepts in a way that encourages curiosity and further learning. Online Survey on Consumer Preferences To gauge consumer awareness and preferences regarding black walnut as a food crop, we launched an online survey. The survey targeted the general public, including those unfamiliar with black walnut products. It was advertised through various platforms, including email lists, social media, and flyers distributed at events and fixed at the Minnesota Arboretum's Apple House. The survey results will inform future outreach strategies by highlighting areas of public interest and knowledge gaps. Extension Articles and Publications: We have published two articles to extend the reach of our project's findings to both the general public and the agricultural community. One article on black walnut syrup production was published in the Minnesota Maple News magazine (June 2024), reaching a dedicated readership of syrup producers. Another article was featured in the Arboretum magazine (October 2024), which helped reach a broader audience of Arboretum visitors and plant enthusiasts. These articles not only disseminate our research findings but also encourage broader interest in black walnut syrup as a potential agricultural product. Building Networks and Collaborations Our project has developed a valuable collaboration with the Minnesota Maple Syrup Producers Association (MMSPA), enabling engagement with producers interested in expanding into black walnut syrup production. This partnership has facilitated an exchange of knowledge and practical skills, benefiting both maple and potential black walnut syrup producers. We have also established collaborations with research institutions, including the University of Missouri's black walnut breeding program. This partnership has expanded our research across a broader geographic area, allowing us to explore the genetic diversity of black walnuts with implications for future agricultural practices. Additionally, improved black walnut varieties from their program were incorporated into our black walnut taste panel. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, we plan to take the following steps to accomplish the project's goals and address any remaining objectives: Finalize the Black Walnut Syrup Taste Panel Paper: We will complete the analysis and finalize the manuscript detailing the findings from the black walnut syrup taste panel. The paper will be prepared for submission to a peer-reviewed journal to disseminate the results to the broader research community and relevant stakeholders. Process and Analyze Data from the Black Walnut Nut Taste Panel: We will process the data collected during the black walnut nut taste panel, perform statistical analyses, and write a manuscript for submission to a peer-reviewed journal. This will help disseminate findings regarding consumer preferences and sensory evaluations of black walnut nuts. Analyze Data from the Online Consumer Survey: We will complete the processing of the data collected through the online survey on consumer preferences and awareness of black walnuts. The results will be summarized and published to disseminate these findings to both academic and public audiences. Submit DNA Samples to DartSeq: We will submit collected black walnut DNA samples to Dart-Seq for genetic analysis. Once the data is received, we will process it to infer the genetic diversity of black walnut genotypes. A manuscript will be prepared to share these findings in a peer-reviewed journal. Second Year of Sap Flow and Sugar Content Evaluation: We will continue with the second year of sap flow and sap sugar content evaluations by collecting and analyzing data from sap flow sensors and weather stations. The analysis will provide additional insights into seasonal variation in sap flow and sugar concentration. We plan to write and submit a paper to disseminate these results. Outreach at Maple Fest 2025: We will participate in Maple Fest to share the results we have obtained so far with attendees. This will include promoting tours of the black walnut grove to showcase the research in action and distributing educational trifolds that provide information about black walnut syrup production and the project's findings. These activities will help engage the public and further promote awareness of black walnut research and its potential applications.

Impacts
What was accomplished under these goals? The project addresses the need to expand black walnut as a viable specialty crop in northern climates by understanding its production potential and consumer appeal. Limited research exists on black walnut sap flow patterns, market demand, flavor attributes, and genetic diversity, which poses a barrier to its broader adoption by regional growers. By generating foundational data on these aspects, the project aims to provide essential insights that will support black walnut cultivation, improve sustainable agricultural practices, and open new market opportunities in the region. This project primarily benefits regional growers and producers by providing key insights into the viability of black walnut syrup and nuts as new market offerings. Extension specialists and industry stakeholders will gain resources to support sustainable black walnut production and outreach. Key Objectives and Accomplishments: Characterizing Sap Flow Peaks, Intensity, and Duration Major Activities Completed: We conducted sap flow measurements on 25 black walnut trees at the University of Minnesota Horticultural Research Center (HRC) from January 31 to March 31, 2024. Additionally, sap flow sensors were installed on 10 trees representing the grove's genetic diversity to collect continuous sap flow data starting in May 2024. Data Collected: Sap yield, sugar content, and DBH measurements were recorded throughout the sap flow season (January to March 2024), with continuous sap flow data monitored since May 2024. Statistical Analyses: A linear mixed model was applied to assess the effect of genotype on sap yield and sugar content, along with a correlation analysis between DBH and sap yield/sugar content. Outcomes: Initial results provide valuable insights into sap flow patterns and syrup production potential in black walnut trees. The linear mixed model analysis revealed that genotype significantly impacts sap yield and sugar content, with some genotypes showing particularly high values. For instance, several trees produced over 20 gallons of sap per tap, and certain genotypes yielded sap with an average sugar content of 4 degrees Brix--higher than the typical sugar content of maple sap (2 to 2.5 degrees Brix) and comparable to maple yields (10 to 20 gallons per tap). Correlation analysis showed no significant linear relationship between DBH and sap yield or sugar content, suggesting these traits are more directly linked to genetic factors. These findings highlight promising black walnut genotypes for syrup production, suggesting that other black walnut populations in northern regions may hold similar potential. The sap flow data currently being recorded, in addition to the 2025 sap flow season data will help regional producers optimize their tapping practices and possibly extend their operations to include black walnut syrup. Understanding the Market Potential for Black Walnut Products Major Activities Completed: An online consumer survey was designed and distributed using the Qualtrics platform to gauge awareness, preferences, and interest in black walnut syrup and nuts. The survey is being promoted at public events and locations such as the Minnesota Arboretum visitor center, the Minnesota Landscape Arboretum AppleHouse, and through online channels. Data Collected: Responses are actively being collected, with a target of at least 200 participants. Once processed, this data will provide valuable insights into consumer attitudes and awareness of black walnut products. Conducting Consumer/Industry Sensory Evaluation Panels Major Activities Completed: Syrup Taste Panel: Held across three sessions in April and June 2024, 106 participants evaluated five syrup samples. Syrups 1 and 2 were identical grade A pure maple syrups, syrup 3 was a commercially purchased pure black walnut syrup, syrups 4 and 5, locally produced from sap at the University of Minnesota Horticultural Research Center and syrup 6 was a black walnut-infused syrup. Nut Taste Panel: Conducted in October 2024, participants assessed the flavor differences between black walnut and English walnut genotypes. Data Collected: Evaluation sessions were conducted on April 13, 14, and June 1, 2024. Participants rated color, flavor, and overall liking using labeled affective magnitude (LAM) and general labeled magnitude (gLMS) scales. Sociodemographic information and syrup purchasing habits were also collected. Statistical analyses included ANOVA to identify significant differences between syrups, with Dunnett's test comparing each black walnut syrup to a maple syrup control and Tukey's test for pairwise comparisons among all syrups. Principal Component Analysis (PCA) helped visualize patterns in sensory data, and regression analysis explored relationships between sensory attributes and overall consumer acceptability, pinpointing flavors that most influenced consumer preferences. Black Walnut Taste Panel: Evaluation sessions were held on October 26 and 27, where 100 participants assessed nine walnut samples, including english walnut, improved and native black walnut genotypes.Sociodemographic information and nut purchasing habits were also collected. Data is still being processed. Outcomes: The syrup taste panel revealed key consumer-preferred attributes, positioning black walnut syrup as a promising, climate-resilient alternative to maple syrup. Significant flavor differences among samples were highlighted by ANOVA, with each syrup displaying a distinct profile. Regression analysis found caramel and maple flavors to be strong predictors of overall liking, with bitterness negatively affecting preference. Sociodemographic results indicated a preference for pure maple syrup among older, higher-income participants. Syrup 5 stands out as a potential mainstream product. These findings emphasize balancing sweetness and nutty flavors in black walnut syrup to support broader market appeal and suggest further research to refine production for consistency and consumer-friendly flavors. The conclusions from this activity provides valuable insights for future product development and marketing and confirms that Black walnut syrup shows potential as a climate-resilient, profitable alternative to maple syrup. A peer-reviewed paper containing these results is in the final stages of preparation for submission. Genetic Testing to Determine Diversity Among Black Walnut Genotypes Major Activities Completed: Leaf tissue samples from black walnut trees and their relatives were collected from the University of Minnesota HRC, the Minnesota Landscape Arboretum, other Minnesota locations, and the University of Missouri's breeding program. These samples were prepared for Dart-Seq genetic analysis. Data Collected: Leaf tissue samples were lyophilized and are set to be sent to Diversity Arrays Technology for Dart-Seq analysis. Once received, the data will be processed and analyzed to assess preliminary genetic diversity among black walnut populations. Outcomes: The results from this activity will provide valuable insights into the genetic diversity of black walnuts in the northern region, supporting breeding programs and contributing foundational knowledge about the species in this area. Summary and Impact: This project has made significant strides in addressing the challenges of expanding black walnut syrup and nut production in northern climates. By generating new knowledge about sap flow patterns, consumer preferences, and genetic diversity, we are building a foundation for future research and applications in agriculture. The results of this project have the potential to enhance the economic viability of black walnut as a specialty crop, creating new opportunities for producers and enriching the local food system. The project outcomes will guide the development of an informed proposal for the 2025 NIFA funding cycle, contributing to long-term research efforts that support sustainable agriculture and the diversification of local crops.

Publications

Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Pessoa, H. P., Miller, B., Anderson, N. O., & Wannemuehler, S. (2024). Optimizing opportunities with black walnut in northern climates: Understanding sap flow patterns and syrup-making potential.ASHS Northern Region 2024 Conference. Virtual.
Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Pessoa, H. P., Wannemuehler, S., Anderson, N. O., & Miller, B. (2024). Sap Yield and Syrup-making Potential of Black Walnut (Juglans nigra L.) Trees in Northern Climates. American Society of Plant Biologists. Honolulu, HI.
Type: Other Status: Published Year Published: 2024 Citation: Pessoa, H. P., Wannemuehler, S., Miller, B. (2024). Tapping into diversity. Minnesota Landscape Arboretum magazine, 6.
Type: Other Status: Published Year Published: 2024 Citation: Pessoa, H. P., Wannemuehler, S., Anderson, N. O., & Miller, B. (2024). Black Walnut Crop Production for Uses in Northern Climates. Poster presentation at NIFAs A1103/A1152 Project Directors Meeting.
Type: Other Status: Published Year Published: 2024 Citation: Pessoa, H. P., Wannemuehler, S., Miller, B. (2024). Black Walnut Crop Production for Uses in Northern Climates. Minnesota Maple News magazine, 3.