Recipient Organization
UNIV OF MINNESOTA
(N/A)
ST PAUL,MN 55108
Performing Department
Horticultural Science
Non Technical Summary
Species diversity in the Midwestern United States has become a principal issue for horticulturists and those that manage landscapes. While consumer interests shift from traditional landscape taxa and cultivars to increased representation of native species and other resilient selections, the green industry remains somewhat limited by the production pipeline of traditional crops that are easily grown and often closely related. Meanwhile potentially adaptable taxa with attributes that merit horticultural attention remain underutilized due to limitations with their production in the nursery. To better adapt to shifting consumer interests as well as improve the supply of more diverse selections, underutilized taxa with horticultural merit should be considered to diversify production and subsequently, managed landscapes. The Center for Winter Hardy Landscape Plants (CWHLP) aims to support the development and production of underutilized and specialty woody perennials to increase diversity of managed landscapes. This process of adoption of specialty nursery crops into cultivation will begin with an assessment of stress tolerances to determine species potential and will work to ease bottlenecks in the nursery by evaluating and generating solutions for production limitations like Mouse Ear Disorder.
Animal Health Component
75%
Research Effort Categories
Basic
25%
Applied
75%
Developmental
0%
Goals / Objectives
Species diversification aimed at increasing resiliency of managed landscapes has become a forefront goal of those that manage landscapes. Underutilized taxa with horticultural merit could be more widely produced and planted, but an absence of information regarding their stress tolerances hinders their popularity while production challenges which have been neglected by research limits plant availability. To support stakeholders, research and extension efforts are needed to create a modern production pipeline that emphasizes the identification of woody-plant taxa tolerant of challenging landscape conditions and solutions to unique challenges faced by growers adopting novel species into production. The research and extension efforts outlined are tailored to addressing these problems. Projects are centered on the identification, assessment, and characterization of unique, underutilized species and selections of woody perennials tolerant of stressful landscape conditions, especially drought. Other goals of this research are to solve production issues currently limiting the availability of desirable taxa for use in the Upper Midwest.The objectives of this project are to:Use predictive tools and controlled cultural conditions to identify adaptable species capable of tolerating drought conditions.Evaluate susceptibility of emerging specialty crop species to Mouse Ear Disorder (MED) and generate protocols for ameliorating symptoms.Advance awareness of stress-tolerant trees and their production protocols in the nursery using outreach and extension programming.
Project Methods
Objective 1: Characterization of Drought Tolerance Using Vapor Pressure OsmometryHealthy branch samples will be acquired from approximately five well established trees, re-cut underwater, and left in complete darkness for one night to reach full turgor. The following day, three 4mm leaf disks will be extracted from each branch and frozen in liquid nitrogen. After freezing, the sample lamina is punctured with forceps and loaded into a vapor pressure osmometer (VPO), equilibrating for ten minutes. Solute concentration (Cs) measurements are recorded from the VPO and plugged into Van't Hoff's relation (Yp = -RTCs) to determine osmotic potential at full turgor (Yp100). This value is then plugged into a tested, temperate-tree corrected equation to estimate leaf water potential at the turgor loss point (Ypo = -.2554 + 1.1243 ยด Yp100), a species-specific threshold after which permanent drought-injury occurs. Species belonging to the following genera will be considered for evaluation in spring and again in late summer from public garden collections: Betula (birch), Pterocarya (wingnuts), and Quercus (oaks). Plants will be sampled from accessions in the Minnesota Landscape Arboretum and data will be bolstered when replicates can be obtained from other public garden collections.The difference in spring and summer values is used to determine the ability of each species to osmotically adjust as they endure the conditions of the landscape throughout the growing season. This research will be conducted by Brandon Miller (Assistant Professor) as an initial study in a new program centered on the development and use of specialty nursery crops.Objective 2: Evaluating Emerging Specialty Crops for Mouse Ear Disorder Susceptibility 2A) Characterize susceptibility of American Persimmon (Diospyros spp.) to MED; develop grower solutions and resources: seedlings (sourced from regional partners and GRIN) of D. virginiana (American persimmon) and its Asian counterparts (D. kaki and D. lotus) will be cultivated, treated, and evaluated (see design below) for MED susceptibility using growth metrics.2B) Characterize susceptibility of hazelnut (Corylus spp. and hybrids) to MED; develop grower solutions and resources: seedlings and clonally propagated hybrid material from the UMHDI will be cultivated in containers and treated with nutrient supplements (see design below). Growth metrics will be used to identify susceptible taxa and clones and develop a protocol for ameliorating MED.2C) Characterize susceptibility of native birches (Betula spp.) to MED; develop grower solutions and resources: seed of the following species will be harvested from plants in the Minnesota Landscape Arboretum and supplemented by orders to the USDA GRIN system. North American: B. pumila (bog birch), B. populifolia (gray birch), B. papyrifera (paper birch), B. occidentalis (water birch). Asian and/or European taxa: B. pendula (silver birch), B. costata (Korean birch), B. davurica (Asian black birch), B. platyphylla (Asian white birch). Plants will be treated with a series of nutrient supplement treatments, including nickel, then evaluated in years two and three for susceptibility to MED.For each component of the MED study, plants will be cultivated using commercial substrates and fertilizers. Treatments will include: non-treated controls, foliar spray urea, substrate drench (Nickel Plus), and foliar spray (Nickel Plus). Additional replicates will be grown and assessed at collaborator nurseries including Bailey Nurseries and Iowa Native Tree and Shrub Nursery. At the conclusion of the second growing season, when symptoms are known to begin occurring, growth metrics (leaf area, leaf greenness, shoot length, caliper, and dry mass) will be leveraged with results of ICP-AES foliar tissue tests to characterize symptoms and susceptibility. Plants will be cultivated in a greenhouse and container nursery at the UMN Horticulture Research Station (Victoria, MN).Objective 3: Using Outreach and Extension to Raise Awareness Around Desirable Species It is essential to extend knowledge acquired through this research to nursery growers and to those that manage landscapes throughout Minnesota. As improved protocols for the cultivation of emerging specialty perennials as nursery crops are developed, information will be disseminated through extension channels, industry and academic conferences, publications, and other forms of communication.Stakeholders will be engaged throughout this project and results will be shared widely. As the study is conducted, updates will be shared in real-time on social media and on the web. An extension field-day will be held at the UMN Horticultural Research Center where growers will be invited to tour the container research block to view the progress of the work and learn how these crops can be integrated into their own production regimens. Further, presentations will be given by student's highlighting the drought tolerance characterizations. This research will be published in open-access, peer-reviewed, scientific journals as well as popular publications like The Scoop or the Minnesota Landscape Arboretum Magazine. A summary of findings will be generated and distributed through on-line extension webpages.