University of Vermont

Horticulture Research and Education Center

Research Open House August 6, 2019

2019 Research Projects Hosted at HREC

UVM Fruit Program     

Dr. Terence Bradshaw                                                                                                       

Rootstock and orchard architecture selection for unique apple production systems

PI: T. Bradshaw
Sponsor: VAES Hatch Funds
Effective Dates: April 2016-March 2018.
Apples are Vermont's second-most valuable specialty crop with total annual value over $10 million. Most Vermont apples are grown for fresh markets and comprise traditional dessert cultivars. However, as dessert apple production has been level for over ten years, increased demand for organic apples and specialty cider apples presents opportunity for growers to exploit those alternative markets and increase sales. Production systems differ for organic and specialty cider apples, and changes from traditional systems presents a knowledge gap among both researchers and growers which limits growing for those markets.
This project includes assessment of rootstock effects on organic and cider apple production systems, as well as multiple leader training systems on cider apples for effects on tree growth, crop yield, and juice quality. Objectives and protocols are part of and informed by the multi-state NC-140 Regional Rootstock Evaluation Trial. Apple production systems are a complex collection of interrelated factors, and this project supports a larger, nationally and internationally-recognized ongoing research program supporting organic and cider apple production in Vermont.

New England Cider Apple Program: Optimizing Production for High-Value Markets

PD: T. Bradshaw. PIs: D. Cooley, J. Clements, J. Pinero (UMASS); R. Moran (U Maine)
Sponsor: Northeast SARE Research & Extension Program.
Effective Dates: September 2019 – August 2022.
Problem and Justification.
In a recent survey of apple growers, one prominent Vermont respondent stated, “The cider apple market represents the first real increase in demand for New England Apples in a generation. While sales of our dessert fruit have been flat or declining, we see this market as essential to maintaining the competitiveness of our industry.”
New England apple growers have increased production of hard cider apples, but currently, demand for such fruit exceeds supply despite potentially high returns. Production of cider apples is limited by: unknown performance metrics for specialty cider cultivars when grown in New England; unique pest management considerations; and alternate bearing cycles that reduce yield. At regional educational meetings in 2014-2017, and in national surveys since 2014, apple growers stated that biennial bearing, cultivar adaptability, appropriate orchard training systems, and increased susceptibility to specific diseases, particularly fire blight, present significant limitations to increased expansion of cider apple production [1-4]. Specialty cider apple cultivars are highly-valued by the growing cider industry, with prices similar to high-quality dessert cultivars that have shown stagnant growth in the past decade. Cider apples also have lower infrastructure and management needs because lack of demand for blemish free fruit creates an opportunity to grow them with fewer chemical inputs. In addition, postharvest cold storage, sorting, and packing are greatly reduced compared to dessert apples.
Solution and Approach. New and existing production practices, specifically bloom thinning, mechanical pruning and reevaluation of pest management models for cider apple cultivars can alleviate these problems, but information on how to implement these techniques without reducing yield or increasing production costs is insufficient. The knowledge needed to best grow cider varieties would enable growers to diversify markets, increase profitability and reduce pesticide use, and enhance the economic and environmental sustainability of their farms. We will conduct an educational program combined with research to compare methods that alleviate biennial bearing, to document the need for crop protection chemicals and establish tolerance levels for primary pests, and to identify cultivars less susceptible to by fire blight.
This bold, multi-state and multidisciplinary project is expected to yield substantial return on NESARE investment, by supporting a growing but challenged component of the New England apple industry that will support new, high-value markets for fruit that will not compete with present dessert fruit markets. Thus, we will help growers to generate new revenue from increased production of a novel crop.

Winegrape cultivar evaluation and virus screening to support the Vermont grape industry.

Sponsor: USDA/Vermont Agency of Agriculture Specialty Crops Block Grants Program.
PI: T. Bradshaw. Oct 2017 – Sep 2020.
The initial UVM research vineyard was established in 2007 under the coordinated, multistate NE1020 project. In its that project, the winegrape cultivars ‘Corot Noir’, ‘Frontenac’, ‘La Crescent’, ‘Marquette’, ‘Prairie Star’, ‘St. Croix’, ‘Traminette’, and ’Vignoles’ were evaluated for horticultural characteristics, crop yield, and juice quality. In 2016, a second trial was established under new project protocols to evaluate the cultivars ‘Crimson Pearl’, ‘Petite Pearl’, ‘Verona’, ‘St Pepin’, and ‘MN 1285’. In addition, virus screening procedures will be developed for Vermont nurseries in order to facilitate certification through the National Clean Plant Network.


Vermont IPM Extension Implementation Program: 2017-2020.

Responding to Need for On-Farm Technical Support for Vermont Apple and Grape Growers

PD: A. Hazelrigg. Co-PIs: S. Bosworth, T. Bradshaw, H. Darby, M. Skinner; T. Bradshaw
Effective dates: Sep 2017 – Aug 2020; Jan 2019 – June 2020
Under this project, timely, evidence-based horticulture and IPM programming is delivered to commercial crop producers in Vermont. Outreach provided to apple and grape producers is informed substantially from observations including formal scouting programs in orchards and vineyards within Catamount Educational Farm. In 2019, project staff and private consultant/collaborator Eric Boire (Crop Production Services, Addison, VT) monitored ten commercial orchards for insect and disease populations in order to quantify pest populations and improve grower management practices. The UIVM Fruit Team also coordinates with partners at Cornell University to support the Network for Environment and Weather Applications (NEWA) supported by ten on-farm and six airport-based weather stations that provide real-time pest modeling output.

Sustainable management of fire blight of apple using plant growth regulators & plant defense inducers.

PD: K. Cox (Cornell); UVM Farm site host: T. Bradshaw
Sponsor: Northeast SARE Research & Extension Program.
Effective Dates: September 2019 – August 2022.
UVM is serving as a host farm for this project, which is based at Cornell and will primarily be staffed by their personnel. Fire blight, caused by the bacterial pathogen Erwinia amylovora, is one of the most devastating diseases of apple worldwide, capable of destroying entire orchards in unforeseen epidemics, and costing farmers millions of dollars in management and damage in the United States annually. Presently, management relies almost exclusively on antibiotic application, which have come under public scrutiny due to the potential for antibiotic resistance development bacterial populations. We will optimize alternative management programs including plant growth regulators, plant defense activators, and biological protectants, materials that have performed well in preliminary testing in research orchards.
We hypothesize that the novel fire blight management programs tested here, including prohexadione  calcium, plant defense activators, and biological products, can be used in an integrate manner to provide both economical and horticulturally sustainable management of fire blight. Specifically, we believe that prohexadione calcium applied pre-bloom at low doses can provide disease control by thickening cell walls, creating a physical barrier to pathogen entry, without reducing tree vigor. Biological materials may provide additional protection by inhibiting and/or outcompeting the pathogen at the point of primary infection. Plant defense activators prime host defenses, making them less susceptible to infection. We will optimize the efficacy of this management paradigm in two productions for maximum disease control and minimum impact on tree productivity.
The objective of this work is to optimize use of the plant growth regulator, prohexadione calcium, natural plant defense activators, and biological antimicrobials to manage the bacterial disease fire blight expressing both as blossom and shoot blight, without the use of antibiotics or compromising tree productivity. To achieve transition to practice, trials demonstrating both disease management and unhindered tree performance will be needed for regionally important cultivars.

Crop Genetics and Domestication Laboratory

Dr. Eric Bishop-von Wettberg

Cold tolerance and rotation value of field peas

Sponsor: USDA NIFA, NE SARE, City Market, von Wettberg Hatch
Effective Dates: 2018--2020
PIs: von Wettberg, Marques

Farmers utilize crop rotations as a method to maintain and improve soil fertility. Legume cover crops are widely used in rotations due to their ability to fix nitrogen, reduce pathogens, decrease soil erosion, and promote soil microbial diversity, all of which increase subsequent crop yields. Despite the benefits provided to conventional and organic agricultural practices, a single cover crop cannot achieve all the cover cropping goals (fixing nitrogen, weed and pathogen suppression, promotion of microbial communities, etc.) desired by farmers. Thus, farmers use multiple legume and non-legume cover crops to fulfill their goals; however, managing multiple cover crops can be time and labor intensive resulting in lower farm profitability. The inefficiency of a single cover crop to achieve a vast set of cover cropping goals is in part due to an insufficient amount of breeding effort to improve the rotational value (how well the crop benefits a subsequently grown crop) of legume cover crops. Therefore, the purpose of this study is to assess the variation of traits (nitrogen fixation, organic matter deposition, microbiome assembly, etc.) associated with cover cropping goals within field pea, a popular cover crop and rotational legume. The data gathered from this experiment will lay the groundwork for improving the rotational value of legume cover crops, which in turn, will benefit farmers with efficient cover crops that will increase yields at lowered costs while simultaneously promoting sustainable agriculture.

Evaluating the climatic adaptation and nitrogen use efficiency of corn varieties for New American Farmers

Sponsor: Gund Institute
Effective dates: Spring 2019- Fall 2020
PIs: von Wettberg, Kur
High quality seed and crop diversity are critical to food security, climate adaptation, and farm system resilience. However, we have a poor understanding of the hierarchy of decisions that farmers make to select seeds that may or may not be culturally and ecologically appropriate, and the extent to which these decisions affect genetic diversity within farming systems. This project seeks to contribute to the growing interest in agriculture and rural livelihoods in the U.S. and internationally through a mixed-methods investigation into a unique and understudied seed system: Vermont-based refugee farmer communities. Through a case study of Chittenden County-based refugees farming with New Farms for New Americans (NFNA), our proposal brings together an interdisciplinary team of UVM researchers and community partners to examine crop diversity within new Vermont farming communities, including lab-based analyses of on-farm genetic diversity; interview-based inquiries into how new Vermont farmers access maize, bean, and other seeds; and mixed-method analyses of the consequences of seed access and crop diversity for: (i) the adaptation of crops to Vermont’s changing climate (climate solutions), (ii) the nitrogen and water use efficiency of farm systems (sustainable agriculture), and (iii) the social and economic livelihoods of farmers (health and wellbeing and resilient communities). The resulting research will strengthen ties between UVM and local organizations seeking to support refugee populations, will result in immediate publications, and will contribute to the pursuit of external funding to further engage UVM faculty, students and local and international partners in continued explorations of seed systems in low-income communities.  Research at the UVM Horticultural Research and Education Center will focus on providing adapted seed varieties of corn and estimating nitrogen and water use efficiency parameters in a controlled common garden.  

Developing new legume crops for Vermont

Sponsor: USDA NIFA, von Wettberg Hatch, USAID Feed the Future
Effective dates: Spring 2018-Fall 2020
PI: von Wettberg
The climate and soils of Vermont poses challenges for cropping systems that are widely used in other parts of the United States.  Consequently, many of the popular legumes for crop rotations, such as soybean and alfalfa do relatively poorly in many parts of Vermont.  Other legume crops however may prove to be valuable additions to vegetable and dairy farm rotations.  This projects explores the suitablity of cultivated lupines (Lupinus angusifoliu, L. albus, L luteus, and L. mutabilis), Asiatic Vignas (Vigna radiata, V. mungo and V. angularis), fava beans (Vicia faba), and green seeded chickpeas (Cicer arietinum) to Vermont soil and production conditions.  Preliminary activities include amplfiying seed from international sources, and crosses to extend variability.

UVM Entomology Research Laboratory                                                            

Dr. Bruce Parker,  Dr. Margaret Skinner

Evaluation of the Efficacy of ERL 836 GR (Beauveria bassiana) against Onion Thrips

Sponsor: Chonbuk National University, South Korea
Effective Dates: April 2019 – October 2022
PI: B.L. Parker & M. Skinner
The UVM Entomology Research Laboratory maintains a worldwide collection of over 2,000 entomopathogenic fungal isolates. One Beauveria bassiana isolate coded ERL 836, collected from avocado orchards, is highly pathogenic to western flower thrips, Frankliniella occidentalis, a major pest of greenhouse ornamentals and vegetables. It is hypothesized that this fungus could also be highly pathogenic to onion thrips, Thrips tabaci, a serious pest in Allium crops. We are collaborating with scientists at Chonbuk National University to determine the field efficacy of a granular formulation of this strain produced by Farm Hannong, South Korea. Two application rates of the granular formulation will be compared with a chemical pesticide and untreated controls. Currently, no granular formulations of B. bassiana are commercially available in the US. If our results show promise, biopesticide companies might be more inclined to offer this product for organic growers in the US. This study will demonstrate how biopestides stack up against conventional chemical treatments. Data on damage and population of T. tabaci will be taken once/week following planting. Randomized leaf sampling will be taken to assess the number of T. tabaci per plant.
Goals and Objectives: Generate efficacy data on two application rates (15 and 30 KG/ha) of a granular formulation of the B. bassiana isolate ERL 836 to manage onion thrips (T. tabaci) in field grown onions and compare the treatment effects with a standard chemical pesticide (Spinetoram an analogue of spinosad), and untreated controls.

Biological Control for Saffron Pests in High Tunnel and Field Production

Sponsor: Vermont Agricultural Experiment Station: USDA Hatch Program
Effective Dates: August 1, 2018 – July 31, 2022
PI: M. Skinner
Date: 19 April 2019

Saffron (Crocus sativus L.) is the most expensive spice in the world, with a retail price >$5,000/lb. Saffron is commonly used as a culinary flavoring and coloring agent in Asian and European cuisine, but also is reported to have medicinal properties, which increases its economic value. In 2015-16 the first Vermont growing saffron was conducted in a high tunnel and in the following years the trial was repeated in the fields. The initial results showed the VT saffron yield surpassed that reported for key saffron-growing areas and saffron could generate $100,000/ acre. Based our early trials, the most significant source of damage and crop loss to saffron is voles and other small mammals. This trial is designed to assess the efficacy different soil treatments to deter damage from voles and rabbits. The treatments include crushed oyster shells applied on the surface and in the soil around the corms, and several repellants. The saffron corms were planted in 3 x 5 ft raised beds in September 2018 at depth of six inches and density of 10 corms/sq. ft. In this experiment, untreated plots serve as controls. Data on saffron yield, leaf area index (LAI) and number of secondary corms are collected annually to compare the direct effect and interactions of the treatments.
Goals and Objectives: The goal of this research is to develop strategies to minimize the negative impact of small mammals (voles and rabbits) for both conventional and organic production. The efficiency of various IPM tactics for minimizing the small mammal damage in saffron plants will be tested over the next 3 years. The plots established at the Horticulture Research Center also serve as a demonstration site to show interested growers how to cultivate saffron.

UVM Farming & Climate Change Program

Dr. Joshua Faulkner, Dr. Rachel Schattman

Turn the tap: Integrated research to support sustainable irrigation practices on northeast vegetable farms

Sponsor: Northeast SARE
Effective dates: 5/1/2019 – 5/1/2022
PIs: R. Schattman, J. Faulkner
Abstract: The northeastern (NE) U.S. is home to a growing vegetable industry. While irrigation is widely used on NE vegetable farms, few growers rely upon soil moisture sensors to schedule irrigation. Many farmers over-irrigate (leading to nutrient leaching) or under-irrigate (leading to decreased yields/quality). Better information about soil moisture conditions, tailored to the scale and diversity of NE farms, can greatly improve irrigation efficiency while protecting water quality/supply in an era of climate change. Soil moisture sensors are commonly used in other regions and sectors, but systems are often not optimized for NE growers, nor are they widely used by this group. Our project will work towards enhanced use and usability of precision irrigation in NE vegetable systems through an integrated field and social science investigation.
Goals and objectives: (1) Develop best practices for deploying soil moisture sensors on diversified farms in the NE and using sensor data to inform irrigation decisions. (2) Develop a better understanding about what NE farmers need from soil moisture monitoring systems to enable them to use it effectively.

UVM Agroecology & Livelihoods Collaborative 

Dr. Ernesto Mendez

Performance of Agroecological Principles; Urban & Periurban Agriculture in Burlington, VT

Sponsor: Northeast SARE
Effective dates: May 2019 – August 2019
PIs: V.E. Mendez, S. Hurley
The goal of this project is to conduct a transdisciplinary agroecological analysis on the opportunities, challenges and resilience of urban and peri-urban agriculture for farmers, the organizations that support them and the cities where they are located. Data collection will be limited to mapping and biodiversity transects to assess (1) the different land use systems within the farm properties and existing internal road and trail systems, and (2) ecological surroundings of the sites. Farm-forest biodiversity transects will highlight land cover change between agricultural fields and surrounding landscape features. We want to identify and characterize the ecological community therein, including predominant native and invasive species, pollinator habitats, riparian buffer dimensions, etc.

Pre and post-harvest strategies for leek moth control

Sponsor: NESARE Research & Extension
Effective Dates: Summer 2019-2021
PIs: V. Izzo, S. Lewins

Leek moth (LM) is a relatively new pest severely affecting allium production in the Northeast. Positively identified in northern New York in 2009, the distribution of this pest now includes New Hampshire, Maine and Vermont. Marketable damage from leek moth can occur at both the pre and post-harvest stages of crop management.  First, during the primary crop growth stage, larval feeding by leek moth can defoliate, damage and/or reduce the photosynthetic potential of hosts plants leading to reduced yields. In addition, wounds associated with larval feeding may expose host plants to secondary diseases and pest infestations leading to even greater crop losses. Finally, post-harvest damage from leek moth larvae can often lead to substantial losses in marketability during crop storage.
Our project looks to test both pre and post-harvest tactics for reducing the impact of the pest at both the pre- and post-harvest stages. These tactics include: the release of a commonly available parasitoid wasp and the adoption of adaptive curing practices to reduce bulb damage from late season LM larvae. The development of non-chemical options for the control of leek moth reduces the dependency on chemical controls, limits the impact on non-target organisms and helps to provide a diversified IPM toolbox for more sustainable control of the LM.

Conservation Biological Control of Cabbage Aphid

Sponsor: Full Proposal Submitted - Pending (Vermont Agency of Agriculture). Pilot Study is funded City Market SEED Grant funds
Effective Dates:                Summer 2019
PIs: V. Izzo, S. Lewins
The cabbage aphid, Brevicoryne brassicae, represents one of the major insect pests of brassica crops in New England. Owing to their unique asexual/sexual reproduction strategies, aphids can exhibit extremely rapid population dynamics leading to sudden outbreaks of economic concern 1. In addition, aphids are known to be vectors of numerous plant pathogens and can induce the growth of sooty mold via the overproduction of carbon rich honeydew 2. Currently, a large proportion of commercial brassica growers, both conventional and organic, rely upon chemical controls to ensure effective control of aphid populations. However, the rapid reproductive rate of aphid populations, the cost of chemical controls and the risks of externalities associated with high insecticide use may preclude growers from a singular chemical tactic. Consequently, there is increasing interest in the development and testing of innovative, low-tech, environmentally benign strategies for aphid control.  
This project looks to address the impact of cabbage aphid infestations in Brussels sprouts plants. The following objectives will be the focus of the upcoming season:
1) To determine the effect of  two commonly used flowering species for the recruitment of natural enemies in brassica agroecosystems;
2) To test the efficacy of the conservation biological control as a tactic for managing cabbage aphid in brassica crops; and,
3) To test the efficacy of Bassiana beauveria (sold as Mycotrol) foliar sprays for managing cabbage aphid in brassica crops.

Insect Agroecology and Evolution Lab

Dr. Yolanda Chen

Field testing of natural semiochemicals to control swede midge, an invasive pest of brassica crops

PI: Yolanda Chen
We will be continuing our trials on a novel “push-pull” type system to manage swede midge in broccoli using both pheromone mating disruption (“pull”) and repellent essential oils (“push”).  Plots will measure 20 m x 16 m and consist of rows of broccoli spaced 30 cm (12”) apart in rows spaced 76 cm (30”) apart.  At HREC we will have two plots, one treated and one control.  Treated plots will have 4 plastic bag-type pheromone dispensers mounted on wire stake in each broccoli row.  The swede midge pheromone consists of (2S,10S)-diacetoxyundecane, (2S,9S)-diacetoxyundecane, and (2S)-acetoxyundecane.  Additionally, the treated plot will receive foliar sprays of garlic essential oil (OMRI-approved Garlic Barrier) every three days.

Each plot will have 4 commercial pheromone monitoring traps for weekly monitoring of pest pressure and to detect “trap shut down” in treatment plots, an expected reaction to pheromone mating disruption.   We will assess crop damage (using the ‘Hallet Scale”) at three, six, and nine weeks of planting. When broccoli crowns are mature, we will harvest the broccoli, score the heads for damage and weigh a subsample of the heads to obtain yield data. Marketable broccoli may be utilized by the farm as appropriate.

Ecological Genomics  

Dr. Stephen Keller

Ecological Genomics of Climate Adaptation in Red Spruce (Picea rubens)

Sponsor: NSF
Effective Dates: Spring 2019–Fall 2021
PI: Stephen Keller
Red spruce (Picea rubens) is a foundation forest tree species whose current distribution is characterized by a distinct zonation into northern core, central margin, and southern trailing-edge populations in eastern North America. This makes it an ideal model system with which to study intraspecific local adaptation to climate through a common garden experiment.
Seedlings grown from seeds of 340 mother trees in 65 populations located throughout the range of P. rubens are being planted in common gardens in Vermont, Maryland, and North Carolina. We will observe how the seedlings respond to the climates of these different latitudes, then link their growth strategies to their population of origin through genetic analysis.
Biologists currently lack a general understanding of the interaction between changes in climate and variation in abundance, genetic diversity, and local adaption from the center to the edge of a species’ range. Our goal is to determine the genomic basis of climate adaptation in red spruce and the sensitivity to range position among contemporary populations to understand the influence of these factors on the P. rubens’ local adaptation to climate change in the past, present, and future.

Local Selection and Hybridization Influence on Climate Adaptation in Populus

Sponsor: NSF; UVM
Effective Dates: Spring 2019–ongoing
PI: Stephen Keller
Poplars (Populus spp.) are under intensive development as a source of both conventional forest products and lignocellulose for bioenergy. Nearly all cultivated poplar genotypes are hybrids, but little is known about interactions between the genomes of hybridizing species yield desirable traits, such as rapid growth, disease resistance, and tolerance to abiotic stress. Further, interactions between genomic variation and local climate conditions are important to tree growth. While this has been extensively studied at large geographic scales in poplar (100’s-1000’s of km), little is known about how such local adaptation may or may not take place at finer spatial scales (10’s-100’s of km). Realizing the potential of poplar as a fast-growing source of fiber and lignocellulose depends on our ability to leverage hybridization and location adaptation to produce highly productive genotypes adapted to spatially variable climatic conditions. This study samples both pure and hybrid genotypes of poplar from different spatial scales and pairs genome-wide sequencing with measurement of plant growth traits under common garden conditions.  Plants are sampled in the field, propagated via rooted cuttings in the greenhouse, and outplanted with replication to HREC under common garden field conditions. After establishment, we will monitor for growth, phenology physiology, and disease resistance traits. This garden also serves as a long-term repository of poplar germplasm that has been intensively studied for its contribution to understanding climate adaptation.

Genomics of Rapid Evolution in Novel Environments: A Coordinated Distributed Evolution Experiment with Arabidopsis thaliana

Sponsor: GrENE net international collaborative network
Effective Dates: Fall 2017–Fall 2020
PI: Stephen Keller
Based at the Max Planck Institute in Germany, the GrENE-net (Genomics of Rapid Evolution in Novel Environments network) project established, from the same genetic pool derived from 231 natural ecotypes of Arabidopsis thaliana, many experimental populations evolving in parallel under different environments. UVM is one of close to 30 sites participating in this experiment in Europe and North America. Flower and soil sampling occurs annually over three years, allowing genetic analysis of successive generations of plants from the same initial gene pool. Differential selection and genotype sorting is expected to cause consistent shifts in abundance of ecotypes and alleles between environments over time.

Other Labs and Affiliates


American Chestnut Germplasm Conservation Orchard

Sponsor: The American Chestnut Foundation
Effective Dates: Spring 2009 – Fall 2024 (or beyond – collection is of long-term value)
PI: K. Collins, TACF; T. Bradshaw, UVM Faculty Sponsor
The American Chestnut Foundation (TACF) is a non-profit organization dedicated to the restoration of American chestnuts to eastern forests.  The American chestnut was once a dominant eastern hardwood species with an estimated population of close to 4 billion trees.  The species has been left functionally extinct by an imported fungal pathogen (chestnut blight), first identified in 1904.  Those trees that do remain on the landscape are of great value to TACF’s restoration programs, which include conventional breeding efforts, biocontrol methods, and biotechnological solutions. 
Existing American chestnuts are scattered on the landscape and often dieback from blight before they can reproduce.  Those that do flower are often isolated and unable to participate in the cross-pollination they need to produce viable offspring.  A germplasm conservation orchard allows for the collection of unique, locally-adapted sources of trees to be replicated and planted in a managed environment.  Trees are planted from nuts produced by the rare open-pollination event or intentional hand-pollination, or as grafts of wild trees.  Transplanting of young seedlings is also possible, though not as common.
The germplasm conservation orchard at the HREC contains unique sources of wild American chestnut from throughout New England.  The oldest trees are just starting to flower, while we are still identifying and planting new sources from across the region.  These trees have been included in the development of genetic mapping tools and grafting experiments.  As they flower they may be used towards the development of new lines of conventionally-bred blight tolerance, and/or the genetic diversification of a transgenic chestnut currently under regulatory review. In addition, there is work currently being done to explore landscape scale diversity of the species, which these this collection will contribute to.

Linking above and belowground interactions in highbush blueberry.

Sponsor: NSF Division of Environmental Biology
Effective Dates: Spring 2019- Fall 2021
PIs: A.K. Brody (Biology), J. Harris (Plant Biology), and Taylor Ricketts (Gund Institute)
The vast majority of all angiosperms engage in multiple mutualisms and do so simultaneously. Most form symbioses with mycorrhizal fungi to gain nutrients in exchange for carbohydrates and most rely on animals for pollination. However, most often plant interactions with these mutualists is studied separately, but knowledge of their links is important. Why? From a basic science perspective, understanding how selection is operating is a fundamental question of evolutionary ecology. Traditional studies of selection on floral phenotypes link pollinators with selection on floral traits. However, plant-mycorrhizal symbiosis may affect floral trait expression but be under different selection pressures. Ignoring third-party interactions, like those with mycorrhizae, may lead to erroneous conclusions about how selection is operating. From the perspective of applied science, maximizing yield in an animal-pollinated plant may require attention not only to supporting local pollinator populations but also to enhancing root symbionts. 
Our objectives are to 1) quantify how mycorrhizae affect floral traits important to pollination and fruit production; 2) examine if plants respond in similar or different ways to inoculation with commercially available mycorrhizal spore mixtures versus raw soils from a nearby farm; 3) measure the effects of differences in pollinator abundance and diversity on the links between mycorrhizal colonization—floral traits—pollinator visitation—reproductive success in highbush blueberry; 4) introduce school-aged children to the importance of pollinators in food systems.
Plants were randomly assigned to three treatments: 1) control plants potted a standard mix of peat, sand and vermiculite (“soil mix”); 2) plants inoculated with commercial fungi and potted in soil mix; 3) plants inoculated with local farm soil from the rhizosphere of the same blueberry cultivar and potted in soil mix.  These plants were then grown and overwintered at the University of Vermont’s Horticultural Research Center.
Plants will be transported to 6 farms in central Vermont for the flowering and fruiting season and returned to the Horticultural Research Center to overwinter.

Population Dynamics of Asian Invasive Earthworms

PI: J. Gorres, PSS             
Sponsor: Vermont Agriculture Experiment Station Hatch Grants Program.
Status: On-going
Asian Earthworms of genus Amynthas Kinberg are relatively new arrivals in Vermont but have already begun to invade sugar bush and riparian forests. At the HRC there are three annual species in this genus: A. agrestis, A. tokioensis and A. hilgendorfii. This study aims to understand the climatic factors that cause interannual variations in population size for A. tokioensis and A. agresteis, the two species that are present throughout the eastern forest at the HRC. The study has found large variations in population size within a year and between years. Drought and frost resistant egg-casings (cocoons) persist late into the year potentially mitigating the effect of drought on population size. The study is now in its 8th year and gives a meaningful long term record of these populations.

Last modified July 23 2019 03:00 PM