The North Dakota State University (NDSU) Woody Plant Improvement Program has been servicing the Northern Great Plains for 70 years, beginning germplasm trial evaluations in 1954. NDSU purchased an 80-acre (~32 hectares) farm in the early 1970s to be established as the NDSU Horticulture Research Farm near Absaraka, ND and began trial plantings in fall of 1974. This research farm provides ideal horticultural soil for evaluation and breeding projects for ND. Approximately 45 acres (~18 hectares) of this farm is used for evaluation, selection and breeding of woody ornamental plants including a 35-acre (~14 hectares) research arboretum. This research arboretum is the most extensive collection of woody ornamental plants in North Dakota and in the Northern Great Plains. There have been over 15,000 accessions obtained, evaluated, and developed since planting began in 1974. Accessions have been collected from local, regional, national, and international sources. After 50 years, this program has introduced 62 superior ornamental woody plants for production and sale with 44 active registered trademarks with the U.S. Patent and Trademark Office. NDSU woody plant introductions have a nursery wholesale sale value of over $2.0 million and a $6.0 million value in retail sales for 2022 alone. Introductions are currently being propagated for sale by commercial wholesale firms in four countries: Australia, Canada, England, and the United States (22 states, including 35 nurseries). The primary focus of this program is with increasing the diversity and availability of woody plants with increased disease/insect resistance and winter hardiness for landscapes throughout North Dakota, region, and nation. One issue that this program is addressing is that native woody (trees and shrubs) plant species diversity is extremely low in the central United States, especially in North Dakota. Most of the available trees and shrubs in the specialty crop nursery trade in North Dakota are non-native introductions. Many non-native plants have been shown to be invasive to native environments. Woody plant research has reacted to this issue utilizing sterility breeding. This results in new cultivars that are not considered invasive and are allowed to be utilized by the commercial nursery and landscape industry, even in states where they are banned. Sterility breeding through polyploid induction has become a focus of the NDSU Woody Plant Improvement Program. The research focus of this project is to induce, or develop, polyploids produce sterile cultivars to be used in the nursery and landscape trade.
Dr. Todd P. West is currently a Professor at North Dakota State University and director of the NDSU Woody Plant Improvement Program. He earned his Ph.D. from Southern Illinois University at Carbondale. The NDSU Woody Plant Improvement Program focuses on the development of new woody... Read More →
Tuesday September 24, 2024 10:00am - 10:15am HST
South Pacific 3
Acer ginnala (Amur maple) and A. platanoides (Norway) are trees that perform well under challenging urban and suburban conditions. Unfortunately, both are highly fecund and have escaped cultivation in several regions of the United States including becoming invasive. To address this, we have developed seedless triploids. To safely deploy seedless cultivars that present little or no ecological risk, they need to be on their own roots, as opposed to being budded onto seedling rootstocks, as was customary for Norway maple. Growing own-rooted plants prevents possible outgrowth of seedling rootstock. Amur maple roots well from stem cuttings but this is not feasible for Norway maple. Micropropagation presents a path forward both to increase propagules rapidly for initial introduction as well as a viable propagation method for the more recalcitrant Norway maple. Both species were successfully micropropagated and stage III plants were delivered in early April 2023. Plants were acclimatized and grown during the 2023 growing season to produce finished trade gallon whips. Material was variable in size because we effectively grew on everything without culling for inferior material. Both species were demonstrated to be amenable to micropropagation and their growth after acclimatization was better than expected. Micropagation will be further optimized, and as available material increases, size and production will be further standardized. This method will facilitate rapid introduction of seedless triploids and allow growers to be successful and profitable in production.
Tea (Camellia sinensis) is the second most popular beverage worldwide and the U.S. annually imports 240 million pounds of tea. The limited availability of tea cultivars and limited knowledge for tea plant propagation are primary barriers for tea production in Washington and the U.S. overall. Time of year and section of shoot for propagation cuttings were tested in northwest Washington for tea cultivar Minto Pacific. Shoots were collected on 8 and 21 Sep, 6 and 24 Oct, 3 and 21 Nov, and 8 Dec 2022, and 18 Jan and 8 Feb 2023, then processed into top, mid, and bottom section cuttings. The bottom end of each cutting was scored (1-2 inches depth) using a knife, dipped into rooting hormone for 5-10 seconds, and placed into a treepot filled with propagation media (5:3:2 ratio peatmoss, vermiculite and perlite, pH 4.5) with the bottom node leaves resting on the mix line. Treepots were placed in a mist chamber with 50% shade and 70-80% relative humidity for 4 months. Survival rate was greatest for shoots collected from 21 Sep through 8 Dec 2022: 99.5% on average 4 months after collection. Cuttings from 8 Sep 2022 had the lowest survival rate overall: 77% at 4 months after collection. Top, mid and bottom section cuttings had an average survival of 96.7%, 95.8% and 94.7% at 4 months after collection. Plant height at 4 months after collection was greatest for cuttings collected on 8 Feb (6.6 cm) and lowest for all other dates (4.5 cm on average). Overall, cuttings from the mid and bottom sections had the greatest plant height at all times: average 5.0 cm at 1 month, average 5.1 cm at 2 months, average 5.2 cm at 3 months, and average 5.6 cm at 4 months. The number of new leaves measured in June 2023 was greatest for top and mid sections of the shoot (3.8 leaves on average) while the bottom section had the lowest number of new leaves (2.8 leaves on average). The overall health rating up to 4 months after collection was highest for cuttings collected on 6 and 24 Oct, and 8 Dec (more than 4.5 on average for all months). The top section of the shoot had the highest rating for overall health in all months (≥ 4.5). Keywords: Camellia sinensis, Cuttings, Northwest Washington, Vegetative
In the Great Lakes region of the United States Christmas tree plantations are established by planting seedlings or transplants. Reducing plant moisture stress after planting is crucial to successful establishment of these small conifers. A myriad of products have been marketed to Christmas tree producers with claims to improve transplant success by limiting transplant shock. Since 2021, we have conducted a series of field trials in collaboration with Michigan Christmas tree growers to evaluate the effect of root dips, mulching and other cultural practices on transplant survival and growth. Root dip products applied immediately prior to planting included: DieHard™ Root Dip (endo/ecto mycorrhizae polymer), MycoApply® Injector Ecto (ectomycorrhizae), SoilMoist™ Fines, and Roots® Terra-Sorb® Fine Planting Gel (polymer). Cultural treatments that were applied following planting included: foliar antitranspirant spray (Wilt-Pruf® [25% di-1-p-menthane]), wood chip mulch, shade blocks (20.3 cm x 30.5 cm mesh screen), controlled release fertilizer, and biochar. Root dips did not affect tree survival or growth in any of the trials. Mulch and shade blocks increased shoot growth at several farms. Improved survival of trees under mulch was associated with improved soil moisture. Mulch did not affect foliar nitrogen (N) concentration, indicating that mulch did not ‘tie-up’ N. The application of Wilt-Pruf reduced transpiration but also reduced photosynthetic rate, resulting in a net decrease in shoot growth. Fertilization at planting significantly reduced survival on two of four sites. Overall, the results suggest that cultural treatments, especially mulch, are more likely to improve plantation establishment than root dips.
Dr. Bert Cregg is a professor of Horticulture and Forestry at Michigan State University. He conducts research and extension programming on the physiology and management of trees in landscapes and nursery and Christmas tree production.
Keywords: Amynthas spp., Biological Controls, Invasive Species, Soil Health, Temperate Ecosystems Jumping worms (Amynthas spp.) present a significant threat to biodiversity and overall soil health across temperate ecosystems. In forest systems, jumping worms alter ecological dynamics by impacting the organic litter layer, soil structure and chemistry, food web functionality, and nutrient cycling processes. These annual, hermaphroditic worms reproduce through parthenogenesis and inhabit the top few inches of moist soils. They survive extreme temperatures in their cocoon stage with the possibility of remaining dormant for several growing seasons. One inadvertent method of jumping worm spread is through container-grown nursery stock and horticultural substrates. In nursery production, jumping worms modify plant quality by consuming organic matter such as roots, altering substrate structure and chemistry in the container, and contributing to excessive nutrient leaching. The rapid movement of these worms may also impact consumer buying potential and preference. There are currently no products listed for controlling jumping worms in the United States, leading to challenges with the management of their spread. We hypothesize that control methods not yet listed for jumping worms in the United States have the potential to effectively suppress jumping worm populations in container-grown crops. Our objective was to further evaluate chemical and biological approaches for managing jumping worms in container nursery production systems. Treatments included a non-treated control, BotaniGardⓇ (2 Tbsp/gal), Thiophanate-methyl fungicide (0.625 mL/400mL), Sodium lauryl sulfate (2 mL/L ), Cedarwood oil (1.5625 mL/L), ConserveⓇ (0.317 mL/400mL), Castaway 3-0-1 Tea Seed Meal Fertilizer (2.7 g/pot), Slug MagicTM (0.5 oz/pot), and SevinⓇ (8.75 mL/400mL). The results of this work suggest differential efficacy between treatments and highlight options with potential for application in horticultural production. Identifying effective control methods benefits the scientific community and the horticultural industry by providing a foundation for future research activities centered on jumping worm management as well as limiting their spread through horticultural products. These findings support growers by outlining potential management practices that demonstrate efficacy for controlling jumping worms in the Amynthas genus.
Research Assistant, University of Minnesota - Twin Cities
Jenna Simon studies invasive jumping worms (Amynthas spp.) with a focus on containerized production. She has a strong passion for the nursery profession and strives to bridge the gap between horticulture and ecology. She believes that ecology should be viewed from many different lenses... Read More →
The Covid-19 pandemic and ensuing lockdowns led to an increase in revenue and production for green industry products in early 2020. In Study 1. an evaluation of fertigation (liquid feed, quick release) and controlled release fertilizers (CRFs, slow release) were applied to container-grown (7 gallon) live oak (Quercus virginiana) and Nutall oak (Quercus nuttallii) trees (100% Liquid feed, 0% CRF, 67% Liquid feed, 33% CRF, 33% Liquid feed, 67% CRF, 100% Liquid feed, 0% CRF). Live oak trees fertilized with CRFs had increased stem calipers (>30%). Nuttall stem caliper and height were significantly increased by 62% and 58%, respectively, with substrate incorporation of CRFs. Live oak tree height was increased by 35% and stem caliper when CRFs were incorporated. In study 2, the effect of alkaline water quality on live oak tree production was initiated at a nursery in Point Coupee Parish. Ca and Mg sources were used to study the impact of water quality on live oak tree container-growth and study the benefits of using different rates of lime and gypsum [0% dolomitic lime (Ca, Mg), 100% gypsum (Ca) Epsom salt (Mg), 25% dolomitic lime (Ca, Mg), 75% gypsum (Ca) Epsom salt (Mg), 50% dolomitic lime (Ca, Mg), 50% gypsum (Ca) Epsom salt (Mg), 75% dolomitic lime (Ca, Mg), 25% gypsum (Ca) Epsom salt (Mg), 100% dolomitic lime (Ca, Mg) 0% dolomitic lime]. Live oak tree growth measurements increased with the reduction of dolomitic lime and increase of Epsom salt and gypsum applications. Leaf Na content was significantly reduced using higher proportions of gypsum and Epsom salt. Soil pH was also reduced by more than 1 pH unit after a growing season. Soil pH did increase when irrigated with highly alkaline water. Growers using alkaline water need to manage irrigation water and soil pH and consider using gypsum and Epsom salt reducing dolomitic lime rates as a source of Ca and Mg. All Ca and Mg sources provided greater than the threshold levels of leaf Ca and Mg content.
