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During the 2021 American Society for Horticultural Science annual conference, the Teaching Methods Professional Interest Group hosted the workshop “Going beyond Zoom: Tips and tricks for teaching horticulture online.” This workshop provided a forum for the dissemination of tools, materials, and approaches used to facilitate active learning in horticulture courses. Here we summarize the topics presented in the workshop as a resource for current and future horticulture instructors.

The advent of horticulture, backed by research, teaching, and extension in the State of Minnesota during the 1800s, had long-term ramifications for initiating opportunities for the newly formed University of Minnesota, the Minnesota Agricultural Experiment Station, and the Minnesota State Horticultural Society—all of which worked closely together. The founding of the horticulture department in 1888, then known as the Division of Horticulture and Forestry, provided long-term commitment to address the needs of the horticulture field. The integration of female students in 1897 provided inclusivity of gender perspectives in horticulture and enabled essential services during World War I (WWI), when male students, faculty, and administrators were drafted into military service. After the sudden death of Dr. Samuel Green, the first Department Head, in 1910, Dr. LeRoy Cady (who served as an Acting Department Head) instituted a novel idea at the time of having weekly departmental seminars. These formally commenced on 13 Jan. 1913, with the first seminar entitled “Organization of the Seminar.” A survey across the country of horticulture or plant science-based departments revealed its uniqueness as being the oldest seminar series in the country and, undoubtedly, the world. An early seminar tradition included taste-testing of fruit. Early seminars were conducted in the department office of the newly built Horticulture Building (opened in 1899). This idea of the seminar format—as a valuable mechanism of exchanging ideas and increasing department associations—was spread by faculty and Dr. Cady at national and regional meetings of the American Society for Horticultural Science. The seminar concept stretched across the country to other universities and colleges with horticulture programs to make such a forum commonplace to convey research, teaching, and outreach findings in academic settings. Knowledge of the history of the seminar series remained obscure until the record book was discovered in 2010, which provided documentation of its founding and the early years of knowledge-sharing in seminar format. To mark this unique event in horticultural science, a centennial celebration of the seminar series occurred on 13 Jan. 2013. An estimated total of 1899 seminars have been presented during this century-long period. However, a gap in the seminars during 1916 to 1925 was unexplained in the record book. Examination of the departmental, college, and university archives during this time period revealed two primary reasons for this: WWI and the 1918 influenza epidemic. The War Department’s takeover of all college and university campuses in 1918 resulted in the decimation of the faculty and student body by mandatory service (all males age 18–45 years), the institution of a wartime curriculum (which limited the number and types of horticulture classes), the takeover of essential departmental functions by nondrafted men and all female students/faculty, the building of barracks (many of which were on horticultural research plots), and the cessation of all activities, including the seminar. Concurrently, the 1918 influenza outbreak prohibited social gatherings, thus limiting interactions such as seminars. Only a few photographs exist of students wearing masks in 1918, but the impact of the flu seriously affected the ability of students to return to the University of Minnesota after WWI. One subtle benefit in 1918 was the first-ever admission of disabled students (veterans) to horticulture classes. The deaths of students, faculty, and administrators on WWI battlefields, in training camps, or by influenza, as well as post-traumatic stress disorder, devastated the department for years. Lessons learned from these tragedies resonate with the modern-day continuation of the seminar series in the context of the current Covid-19 pandemic.

The genus Linum L. contains ≈200 primarily blue-flowered species, including several ornamentals, yet no reports exist regarding the cut flower potential of this genus. The objective of this study was to evaluate the cut flower potential of perennial flax cultivars (L. perenne L. ‘Blue Flax’ and ‘Sapphire’; Expt. 1, 2018) and accessions (L. austriacum L., L. lewisii Pursh., and L. perenne; Expt. 2, 2019), and record traits that will enable breeding and selection for improved cut flower performance. The mean vase life across both cultivars in Expt. 1 was 9.2 days. In Expt. 2, L. perenne had the longest average vase life (9.3 days), followed by L. austriacum (9.1 days) and L. lewisii (8.3 days). The floral preservative (Floralife 300) significantly increased vase life by an average of 1.7 days in Expt. 1, and 1.6 days in Expt. 2, and resulted in a significantly greater number of flowers (≈2x) in both experiments. Significant variation was observed among genotypes for most traits, including vase life (6.2 to 11.3 days) and number of flowers (1.3 to 10.5), highlighting the opportunities for improving the potential of cut flower perennial flax through breeding.

Knotweed (Fallopia spp.) is an herbaceous perennial from East Asia that was brought to Europe and North America and, despite control efforts, subsequently spread aggressively on both continents. Data are available on knotweed’s modes of sexual and asexual spread, historical spread, preferred habitat, and ploidy levels. Incomplete information is available on knotweed’s current global geographic distribution and genetic diversity. The chemical composition of knotweed leaves and rhizomes has been partially discovered as related to its ability to inhibit growth and germination of neighboring plant communities via phytochemicals. There is still critical information missing. There are currently no studies detailing knotweed male and female fertility. Specifically, information on pollen viability would be important for further understanding sexual reproduction as a vector of spread in knotweed. This information would help managers determine the potential magnitude of knotweed sexual reproduction and the continued spread of diverse hybrid swarms. The potential range of knotweed and its ability to spread into diverse habitats makes studies on knotweed seed and rhizome cold tolerance of utmost importance, yet to date no such studies have been conducted. There is also a lack of genetic information available on knotweed in the upper Midwest. Detailed genetic information, such as ploidy levels and levels of genetic diversity, would answer many questions about knotweed in Minnesota, including understanding its means of spread, what species are present in what densities, and current levels of hybridization. This literature review summarizes current literature on knotweed to better understand its invasiveness and to highlight necessary future research that would benefit and inform knotweed management in the upper Midwest.

The issue of native invasive species management rarely occurs and is fraught with biological, social, and economic challenges as well as posing difficulties in decision-making for land managers. The terminology for categorization of invasive species is examined in the context of their bias(es), which complicates control. An example of a newly determined native species, which is also invasive, is used as an example to navigate control and regulatory issues. Native, invasive reed canarygrass (Phalaris arundinacea L.) occurs throughout Minnesota and most likely the entire midwest region of central United States and Canadian provinces. The species was previously assumed to be an exotic, nonnative Eurasian import but recent molecular evidence supports its status as a native but invasive species. We address how this change to being a native but highly invasive species modifies approaches to mitigate its potential control for state, Tribal, and local authorities. The implications of these new findings will require differential shifts in land managers’ perspectives and approaches for control. Particular differences may exist for Tribal Land Managers vs. departments of natural resources and private agencies. Additionally, regulatory challenges have yet to be decided on how to legislate control for a native invasive species that had been previously assumed as exotic or foreign in origin. These opportunities to change attitudes and implement judicial control measures will serve as a template for other invasive species that are native in origin.

Background. Chrysanthemum arcticum, Arctic daisy and its two subspecies (C. arcticum subsp. arcticum, C. arcticum subsp. polaré) are the only chrysanthemum species native to North America. A study on species’ variation in morphological and diagnostic traits is important to link morphological traits with previously described single nucleotide polymorphism (SNP) markers, particularly when the genomes are sequenced. The purpose of this study was to establish phenotypic differences and soil conditions among wild C. arcticum and C. a. subsp. arcticum populations, when grown in a uniform environment, for potential linkages with our SNP library. Sixteen quantitative morphological traits and five qualitative morphological traits were investigated for 255 individuals from nine C. arcticum populations and 326 individuals from 21 C. a. subsp. arcticum populations.Results. While 100% of the C. a. subsp. arcticum individuals flowered under long days, 0% of the C. arcticum individuals flowered in 2018 while only 2.7% flowered in 2019. Two distinct clusters, distributed by taxonomic classification, were detected by Principal component analysis (PCoA) for 551 individuals from C. arcticum and C. a. subsp. arcticum. Pearson’s correlation coefficient analysis indicated a positive and significant correlation between plant height, flower fresh and dry weights. Flower fresh weights were correlated with Δflower weight, while inflorescence length had showed a negative correlation with leaf number. Soil samples had high Na levels along with heavy metals. Thus, the species are salt-tolerant.Conclusion. A high level of salt tolerance (Na) is tolerated by these maritime species which is a unique trait in Chrysanthemum. A new diagnostic trait of inflorescence length was discovered to distinguish among C. arcticum and C. a. subsp. arcticum. Significant flowering differences occurred among the species wherein C. a. subsp. arcticum had 100% flowering in long days whereas C. arcticum had 0% to 3.1%. The mean number of weeks to visible bud date in C. a. subsp. arcticum is the fastest (2.2 wks.) ever reported in Chrysanthemum, in contrast with C. arcticum which is the longest (65.3-69.4 wks.). This study on the species’ variation in morphological and diagnostic traits is of importance to link morphological traits with single nucleotide polymorphism (SNP) markers.

The native vs. exotic status of reed canarygrass (RCG), a major invasive species of Minnesota wetlands, is unknown. The aim of this study was to investigate this native vs. exotic status to enhance its management. Genetic comparison of wild RCG populations from six Minnesota and six Czech Republic rivers was performed. A total of 2521 polymorphic SNP markers (single nucleotide polymorphisms) were used to evaluate 478 RCG samples across all collections. In the PCoA, all (n = 256) tested extant wild, riparian RCG genotypes from six Minnesota Rivers and six Czech Republic Rivers were genetically distinct, although some SNPs were common in both populations since they are the same species. DAPC analysis also resulted in the formation of two primary clusters separating the Minnesota Rivers and Czech Republic Rivers riparian samples, with little overlap; STRUCTURE analysis also supported this clustering with k = 4 groups as it separated the Czech Republic Rivers populations into three groups, along with Minnesota Rivers. The uniformity of PCoA, DAPC, STRUCTURE, and Evanno results indicates the distinct separation of Minnesota Rivers and Czech Republic Rivers populations. Portions of the genome (specific SNPs) are preserved or in common across continents, as indicated by STRUCTURE similarities. Nonetheless, overall significant SNP differences between the continents indicate that the Minnesota riparian populations are distinct enough from the European (Czech) collections to be delineated as native N. American RCG. PCoA of all the Minnesota RCG collections clustered Minnesota Rivers, Herbarium, Extant Herbarium, Research Field and Native Field collections together. STRUCTURE analysis (k = 2; Evanno) divided these Minnesota collections from the Commercial Field and Cultivars collections. There are two genetically distinct groups of RCG in Minnesota and since the Minnesota Rivers, the Research Field, the Native Field and pre-1930 herbaria collections clustered together, they are most likely native N. American types. Analysis of molecular variance (AMOVA) indicated that the genetic variation was more significant within, rather than among, the RCG populations. Native, historic herbaria types cluster together with all wild RCG river populations in Minnesota, all of which were distinct from those in Central Europe, suggesting native RCG type persistence in N. America. Also, cultivated forage types of RCG are distinct from wild RCG Minnesota river populations. The SNP genetic data shows that riparian Minnesota RCG populations are native. These data will facilitate future management strategies to control RCG as a native, but invasive, species.

The present study systematically investigated the effects of warehouse and greenhouse aquaponic growing conditions on consumer acceptability of different basil cultivars. A total of 105 consumers rated their liking of three basil cultivars (Nufar, Genovese, and Eleonora), each grown in three conditions (aquaponically in a greenhouse, aquaponically in a warehouse, both with Cyprinus carpio, Koi fish, and grown in soilless medium). We used linear random effect models to investigate consumer preferences for attributes of basil plants grown in different environments by controlling for individual-specific random effects. Participants generally liked the soilless medium–grown and greenhouse aquaponically grown basil plants more than the warehouse aquaponically grown plants. The soilless medium–grown basil had the highest appearance liking and flavor intensity, followed by the greenhouse aquaponic grown and then by the warehouse aquaponic grown. Aquaponically grown cultivars were rated less bitter than soilless medium–grown cultivars.

In cases where invasive species are presumed to be strictly exotic, the discovery that the species is also native can be disconcerting for researchers and land managers responsible for eradicating an exotic invasive. Such is the case with reed canarygrass (Phalaris arundinacea), for which decades of misinformation led to the call for nationwide control of this species in the United States. However, native populations were first reported by LaVoie and then later confirmed by Casler with molecular analyses. This, coupled with the discovery by Anderson that this species has been used in weavings by Native Americans for centuries, also made the native forms of interest for protection. Identifying the native status of historic, herbarium specimens via molecular analyses is of great interest to determine localities of native populations for confirmation with extant specimens. Genetic-based methods describing DNA polymorphism of reed canary grass are not well developed. The goal of the presented research is to assess the utility of genomic DNA obtained from historic (herbaria) and extant (fresh) tissue of reed canarygrass and the application of using Diversity Arrays Technology sequencing low density for genetic population studies.

Aquaponics, the combination of hydroponics and aquaculture into one growing system, is a controlled environment production system that potentially has increased environmental and consumer benefits over traditional production methods. There are many different ways to configure aquaponics systems that include different fish species, water circulation, lighting, plant species/density, and more. We tested three cultivars of lettuce, a common aquaponically produced crop, for yield in multiple aquaponic systems and conditions over a 13-month period in Minnesota. Four different aquaponic configurations and four types of fish were tested over the course of the experiment. There was no addition of supplemental nutrients to the systems to evaluate the differences between treatments and set a baseline. There was no difference in yield between lettuce produced aquaponically and those grown in soilless medium. However, there was a difference in yield between lettuce grown with different fish treatments. The tilapia treatment produced higher average yield than yellow perch. There was a difference between cultivars, with higher average yield from loose-leaf bunch cultivars (Salanova, Skyphos) than the bibb type (Rex). Average yield for all but one treatment was above that of reported commercial field production, making lettuce a competitive aquaponic crop in most systems.

Background. Gladiolus is a geophytic floricultural crop cultivated for cut flower and garden ornamental uses. Monocotyledonous flower crops have few, if any, flowering genes identified. Ornamental geophytes such as gladiolus, lily, tulip and daffodil are examples of floral crops that are currently being investigated to understand the flowering pathway. While the flower genes and environmental / hormonal factors leading to flowering are established in Arabidopsis, the lack of identified flowering genes in economically important ornamental geophytic crops, such as gladiolus, is critical to further genetic research. Thus, the importance of such an ornamental crop that relies on flowers (flowering) for economic purposes encourages researchers to discover the flowering genes to breed vigorous, flowering cultivars. The understanding of the flowering mechanisms in the flowering pathway is also of paramount importance. Results. Herein we show the discovery of UPSTREAM OF FLOWERING LOCUS C (UFC) and FLOWERING LOCUS C EXPRESSOR (FLX) genes in Gladiolus ×hybridus and G. dalenii. The UFC gene is adjacent to FLOWERING LOCUS C (FLC) which is a floral repressor in many temperate species. The FLX gene upregulates FRIGIDA (FRI) which upregulates FLC expression. Discovery of both genes is a step forward in finding the FLC gene in gladiolus, provided they are linked. Seventeen gladiolus genotypes, consisting of early flowering and commercial cultivars, were discovered to possess the UFC gene, consisting of four exons in two allelic forms. The sequenced UFC gene, when translated into its amino acid sequence and set in pair-alignment to other species, has up to 57% in amino acid identity to Musa acuminata. The UFC protein ranges in identity with pair-alignment to other monocot species, also with 57% amino acid identity to M. acuminata. The FLX gene in gladiolus has 3/5 (60%) exons in common relative to Ananas comosus, i.e. lacking 2 exons and a partially complete gene sequence; the pair-alignment of the three exons shows an overall ~65% identity of FLX to A. comosus. The UFC protein consists of a conserved domain, DUF966, which is higher in identity (86%) and pair-alignment with Elaeis guineensis. Conclusions. The two newly-discovered genes in gladiolus, UFC and FLX, provide insight to further our understanding of the flowering mechanism, flowering pathway genes, and vernalization response in ornamental geophytes. This knowledge will be valuable for gladiolus breeders and geneticists to finding the FLC gene, identify segregating seedlings for both UFC and FLX, and aid in marker assisted selection for flowering gene expression.

Gladiolus is a geophytic floricultural crop, cultivated for cut flower and garden ornamental uses. Ornamental geophytes such as gladiolus, lily, tulip and daffodil are examples of floral crops that are currently being investigated to understand the flowering pathway. While the environmental and hormonal factors leading to flowering are established in Arabidopsis. However, the lack of genetic regulation is poorly understood. Thus, the importance of such an ornamental crop that relies on flowers (flowering) for economic purposes encourages researchers to discover the flowering genes to breed vigorous flowering cultivars. The understanding of the flowering mechanisms in the flowering pathway is also paramount. Herein we show the discovery of UPSTREAM OF FLOWERING LOCUS C (UFC) and FLOWERING LOCUS C EXPRESSOR (FLX) genes in Gladiolus ×hybridus and G. dalenii. The UFC gene is adjacent to FLOWERING LOCUS C (FLC) which is a floral repressor in many temperate species. FLX gene upregulates FRIGIDA (FRI) which upregulates FLC expression. The discovery of both genes is a step forward in finding the FLC gene in gladiolus, provided they are linked. Seventeen gladiolus genotypes, consisting of early flowering and commercial cultivars, have the UFC gene, consisting of four exons in two allelic forms. The UFC gene sequenced when translated into amino acid sequence and set in pair-alignment to other species, has up to 57% in amino acid identity to Musa acuminata. The UFC protein ranges in identity with pair-alignment to other species, reaching up to 57% in amino acid identity to Musa acuminata. The FLX gene in gladiolus has 3/5 (60%) exons in relative to Ananas comosus, i.e. lacking 2 exons and a partially complete gene sequence; the pair-alignment of the three exons shows up over all ~65% identity of FLX to Ananas comosus. The UFC protein consists of a conserved domain, DUF966, which is higher in identity and pair-alignment, with up to 86% identity in Elaeis guineensis. The discovered FLX gene in gladiolus has 3/5 (60%) exons, i.e. lacking 2 exons and a partially complete gene sequence; the pair-alignment of the 3 exons shows up to ~65% of identity of FLX to Ananas comosus. These discovered two genes in gladiolus provide insight to further our understanding of the flowering and vernalization response in ornamental geophytes.Summary StatementTwo gladiolus flowering genes (UFC; FLX) were discovered which will aid research in understanding flowering and vernalization in geophytes

Lengthy generation times in herbaceous perennials (1 to 5-10+ years from seed to flowering) impede the rate of progress flower breeders can make during breeding and/or domestication of floricultural crops. Geophytic herbaceous perennials, i.e., those with over-wintering underground storage organs (rhizomes, bulbs, corms, tubers etc.), have the added complication of the need for meristem size for vegetative to reproductive phase change competency and increased flower bud number. Consequently, these and other factors necessitate that most geophytic floricultural crops are primarily vegetatively (asexually) propagated. The University of Minnesota Flower Breeding and Genetics program has focused>20 years to reduce the generation time in many geophytic crops, including monocots (Gladiolus, Lilium, Iris) and dicots (Chrysanthemum), using a suite of selection techniques from seed germination onwards to flowering. Our objectives are to compare the selection techniques which have accomplished these goals: time (week) of seed germination, rate of subsequent growth, contractile root formation (corm and bulb crops), leaf number, leaf unfolding rates, stem elongation, stem and inflorescence height, internode number and length, propagule formation (size, weight), visible bud date and flowering, and flower number. Germinating seedlings were tooth picked each week with a different color each week to designate germination weeks (G1 for week 1, etc.) which enabled selecting and transplanting only the earliest germinators/generation. In most crops (Gladiolus, Iris, Chrysanthemum), seed germination during weeks 2-4 after sowing (G2-G4) was highly correlated with visible bud dates and flowering, even if early generations flowered after Year 1. In Lilium, however, G1-G2 seedlings had earlier flowering than those in G3-G8. Incorporation of these techniques along with fast cycling within geophytic breeding programs can enhance the rate of progress made per generation, particularly when the annual cycle is reduced to 3-4 months instead of 12. Comparative analyses of traits within and among each crop allows for creating crop-specific strategies to reduce generation time and maximize gain from selection.

Aquaponics is the integration of aquaculture and hydroponics to grow fish and plants together in one system. Many producers in the northern United States are attracted to aquaponics for its potential to produce indoors year‐round. However, little is known about consumer preferences for products grown in aquaponic systems. To address this knowledge gap, we conducted an experimental auction to measure the impact of information about production method on consumers’ willingness‐to‐pay (WTP) for lettuce. For most participants, WTP was similar for both aquaponic and soil grown lettuce with overall average bids of $1.47 per 8 ounces and $1.48 per 8 ounces, respectively. Learning how samples were grown (either aquaponic or soil‐grown) rarely changed bids significantly, although on average, participants with environmental group membership lowered their bids for aquaponic lettuce samples. In general, higher frequency shoppers expressed higher average WTP for all types of lettuce. [Q100 Agriculture: General, Q220 Renewable Resources and Conservation: Fishery; Aquaculture]

Aquaponics, an integrated system with both hydroponic plant production and aquaculture fish production, is an expanding alternative agriculture system. Many key questions about the overall feasibility of aquaponic systems remain unanswered. Of particular concern for start-up and established producers alike are consumer perceptions and willingness to pay for aquaponic produce and fish. This study reports results and analysis of a consumer survey about perceptions and preferences for aquaponic-grown products that was conducted in Minnesota during Feb. 2016. Probit and ordered probit models are used to evaluate the probability of different consumer demographic segments having various levels of knowledge and perceptions about aquaponics. About one-third of respondents had previously heard of aquaponics, and upon learning more about the system through the survey, respondents tended to be generally neutral or favorable to aquaponics. Price might be an issue for many consumers, but many tend to believe that aquaponics can impact the environment in a positive way. The results represent a first step toward building knowledge about the potential consumer base for aquaponics, which is a critical piece in the system’s potential overall profitability. It appears that consumer education and marketing will be key for the expansion of the market.

A new garden chrysanthemum with a shrub plant habit is released as a descendent of a cross involving two hexaploid species: Chrysanthemum weyrichii (Maxim.) Tzvelv. (female) × C. ×grandiflorum Tzvelv. (male). Chrysanthemum ×hybridum Anderson MN 98-89-7 [U.S. Plant Patent (PP) 14,495] is a vigorously growing shrub chrysanthemum for garden culture, exhibiting extreme hybrid vigor. Single daisy reddish-purple flowers cover the foliage in the fall, numbering >3000 on second-year plants. This selection displays excellent winterhardiness in U.S. Department of Agriculture (USDA) Z3b+ (–34.4 to –37.2 °C) as well as frost-tolerant flowers. In its second and subsequent years of growth after planting, MN 98-89-7 grows into a fall flowering (August–October), herbaceous shrub ranging in plant height from 61.0 to 91.4 cm with a diameter of 76.2 to 152.4 cm. Its spherical plant shape is achieved naturally with self-pinching, creating a highly manicured appearance; it also attracts honey bees and butterflies as pollinators. MN 98-89-7 is a vegetative product and this unnamed selection is being released for germplasm purposes as well as for potential licensing and naming.

Global warming has created increased nighttime temperatures both in field and greenhouse production of chrysanthemums during flower bud initiation (FBI) and development, causing heat delay or complete cessation of flowering. Integration of breeding and selection for heat delay insensitivity (HDI) has become imperative for greenhouse (cut, potted types) and must be accomplished on a genotypic basis, similar to winterhardiness. This is a breeding objective in the joint garden chrysanthemum breeding project between the Chungnam Provincial Agricultural Research and Extension Services and the University of Minnesota. The objectives of this research were to test 10 genotypes (cultivars, seedlings) from both breeding programs when grown in low-temperature (LT) and high-temperature (HT) short-day (SD) and long-day (LD) conditions (four environments: LTSD, LTLD, HTSD, and HTLD); determine the extent of heat delay and HDI for visible bud date (VBD), flowering, and other phenotypic traits; evaluate relative injury (RI) and cell membrane thermostability (CMT), and to select future parents with lowered RI values, higher CMT, shorter heat-induced flowering delay, and/or HDI. ‘Magic Ball’ and ‘Minnwhite’ had the shortest plant height in HTLD and HTSD, whereas ‘Geumbangul’ had stability for height in all treatments. Lowest long day leaf numbers (LDLN) occurred under LTSD in seven genotypes. However, both ‘Geumbangul’ and ‘Magic Ball’ had complete stability for LDLN across all environments. Sigmoid curves for RI% and temperature were found for all genotypes and environments with R2 = 0.79–0.89. Only ‘Mellow Moon’ had stability or equal VBDs in HTSD, LTSD, and LTLD conditions. This is the first-ever report of stability for VBD across inductive and noninductive HT/LT treatments. Only ‘Centerpiece’ flowered in all environments and also had 0 day of heat for VBD in LT and 1 day of heat delay in HT, as well as three others (Mn. Sel’n. 01-210-43, ‘Autumn Fire’, and ‘Geumbangul’). Few had linear regressions with positive slopes for heat-induced VBD or flowering delay regressed with RI%; most had no slope (R2 ≈ 0.0) for all treatments (‘Centerpiece’, Mn. Sel’n. 01-210-43), whereas others were negative (‘Mammoth™ Dark Bronze Daisy’, Flw LTLD–LTSD). Surprisingly, one linear regression had a slope of R2 = 1.0 (‘Geumbangul’, Flw LTLD–LTSD). These responses are all novel in chrysanthemums. Selecting the best parents in both breeding programs to maximize stability of all traits across these four environments with minimal crossing and selection across generations could be accomplished by stacking parental traits. A crossing scheme involving just three parents is proposed to incorporate stability for all traits in just a few generations.

Flaxseed (Linum usitatissimum) has recently grown in popularity as a health food due to its high levels of omega-3 fatty acids. Many undomesticated Linum species possess a similar oil profile, in addition to perenniality, and could, therefore, provide similar products in addition to ecosystem services such as soil retention, improvements in water quality, and pollinator services. Many Linum species also possess ornamental qualities, e.g., blue flowers, which could provide added value as a new cut flower crop or garden herbaceous perennial. A perennial flax breeding program will be initiated by screening of Linum accessions for key agronomic and horticultural traits. Herein, we outline an ideotype approach which will enable identification of top herbaceous perennial candidates for domestication based on qualities relevant to oilseed, cut flower, and garden herbaceous perennial crop uses. In this review, we summarize the concept of ideotype breeding as it relates to perennial crop domestication and outline considerations for ideotype design. The tools outlined herein should prove useful to other breeders and especially for undomesticated crops. Whether the ideotype concept is applied as a framework for selection or simply as a means of generating hypotheses, applying this approach can provide structure to breeding programs with complex objectives.

The spread of invasive wetland plants has resulted in a number of negative impacts to wetland habitats including reductions in biodiversity, displacement of native plants, and altered water flow. Phalaris arundinacea L. (Reed canarygrass) is a highly competitive invasive plant in North American wetlands. While research has focused on growth characteristics and competitive ability of P. arundinacea in wetland habitats, little is known about how its growth in upland conditions differs from that in wetlands. To characterize differences in growth between upland and wetland habitats, we conducted a 13-month field experiment of unconstrained growth of P. arundinacea in upland and wetland conditions. A suite of traits was measured in genotypes collected from upland and wetland habitats. Although P. arundinacea most often occurs in wetlands, there was significantly higher growth and fecundity in the dry soil treatment. All of the growth traits measured varied among genotypes, a few varied between the habitats of origin, and significant interactions were found between habitat of origin and soil moisture treatment for several traits. The significant genetic variation observed suggests that there is potential for local adaptation to upland habitats. The higher growth and fecundity in upland conditions highlights the need for additional research to investigate P. arundinacea establishment capacity and competitiveness in upland habitats.

Geophytic floricultural crops, i.e., those with underground storage organs, are primarily vegetatively (asexually) propagated. During breeding, domestication, and continued crop improvement, sexual cycles are necessary to study trait inheritance and select new genetic variation. The University of Minnesota Flower Breeding and Genetic program is breeding new phenotypes of Gladiolus, a cut flower and garden crop with corms. Typical generation cycles from seed to flower take 3-5 years. Our objectives were to create a rapid generation cycling process to select early flowering seedlings and enhance the rate of genetic improvement. Techniques under evaluation include germination (week) in the plug phase and correlation with flowering date, fast cycling of generations (2-3/year), along with selection of high leaf number and early stem stalk emergence in cycles 1-3. A total of 71 crosses and N=1,026 seedlings were evaluated in this study. Seedlings germinated primarily in weeks 2-4 after sowing although some crosses took until week 7. All seedlings had one leaf/plant in cycle 1; whereas in cycle 2, leaf counts ranged from one to seven. By cycle 2, 6% of the seedlings (primarily from six crosses) also had elongated stems with 1-4 leaves/stem. Stem elongation in cycle 2 is a highly heritable trait. Cycle 3 plants with elongated stems flowered, reducing generation time as much as 1-2 cycles. As many as three cycles (generations)/year could be accomplished consisting of reduced greenhouse growth, dry down and cold storage treatments.

The value and role of intellectual property (IP) rights pertaining to plant innovations and their economic consequences on plant values is largely unknown. A hedonic pricing model was adapted to the characteristics of the U.S. wholesale ornamental plant market, specifically the bedding, garden plant and nursery plant markets, to analyze two forms of IP rights used on plants (i.e., plant patents and trademarks). By controlling plant-specific attributes and a variety of market variables that might affect plant values, our empirical analysis reveals sizable price premiums for plant patents that may have been masked in other studies. As expected, plant patent premiums vary considerably between species where the costs of producing and marketing new cultivars differ greatly. Surprisingly, we find that the use of trademarks have a negative effect on plant prices.

Luther Burbank (1849–1926) was a prolific ornamental plant breeder, who worked with 91 genera of ornamentals, from Abutilon to Zinnia, and released nearly 1000 cultivars to the industry. His innovative work included both herbaceous and woody plant materials as well as ornamental vegetables such as corn, tomatoes, and spineless cacti. His most popular ornamental release, the shasta daisy hybrids—first released in 1901, is still on the global market. This article focuses on Luther Burbank’s breeding techniques with ornamental plants and how both the germplasms that he developed and his methodologies used permeate modern flower breeding. Genera with the highest number of cultivars bred and released by Burbank include Amaryllis, Hippeastrum, and Crinum followed by Lilium, Hemerocallis, Watsonia, Papaver, Gladiolus, Dahlia, and Rosa. With Lilium, he pioneered breeding the North American native lily species, particularly those from the Pacific coastal region, producing the eponymous Lilium ×burbankii. Burbank’s breeding enterprise was designed to be self-sustaining based on profits from selling the entire product line of a new cultivar or crop only to wholesale firms, who then held exclusives for propagation and selling, although financial hardships necessitated selling retail occasionally. Entire lots of selected seedlings were sold to the highest bidder with Burbank setting the price in his annual catalogs such as the Burbank Hybrid Lilies lot for U.S. $250,000 or some of the “very handsome, hardy ones” for U.S. $250 to U.S. $10,000 each. Other flower cultivars also commanded high prices such as seedling Giant Amaryllis that sold for U.S. $1.55/bulb in 1909. Cacti were another area of emphasis (he released more than 63 cultivars) from the spineless fruiting and forage types (Opuntia ficus-indica, O. tuna, O. vulgaris) to flowering ornamentals such as O. basilaris, Cereus chilensis, and Echinopsis mulleri. Interest in cacti during 1909–15 rivaled the Dutch Tulip mania with exorbitant fees for a single “slab” of a cultivar, speculative investments, controversy with noted cacti specialists (particularly David Griffiths), and lawsuits by The Burbank Company. Although most cultivars have been lost, Burbank’s reputation as the Father of American Ornamental Breeding remains admirable from critics and devotees alike.

Genetically modified organism (GMO) crops provide new trait(s) that may benefit floral designers and consumers. A limited array of GMO cut flower cultivars exist in the floral markets worldwide: nine carnations (Dianthus caryophyllus) and one rose (Rosa ×hybrida). Labeling GMO flowers in the United States is not required. Thus, most distributors, flower auctions, brokers, wholesalers, floral designers and consumers are not aware that they exist. To test the acceptance of GMO cut flowers with potential future floral designers, n = 121 students enrolled in Floral Design (HORT 1013) at the University of Minnesota during 2005–07, 2009, and 2011, designed with standard and miniature GMO Moon™ series carnations. Each student created a Hogarth design with both types of carnations and assembled a price sheet. Students examined the differences between GMO lavender/purple carnations and those created with classic methods of spraying, dipping, or infusion. In 2009 only, students were also assigned to write a marketing paragraph about their GMO floral design. Each year, students were given an identical question on a subsequent midterm examination to determine their position on GMO cut flowers, including development of a floral shop policy to inform customers. Student examination responses ranged from not carrying GMO products [1/121 (0.8% response)], offering GMO/non-GMO carnation options to the consumer [81/121 (66.9% response)], or only selling only GMOs [33/121 (27.3% response)] that differed significantly from a 1:1:1 chi-square (χ2). A significant majority of students would inform their customers of the GMO crops [89/121 (73.6% response)]. In several instances, consumers were not to be informed of the GMO nature unless they queried about the higher price point. Similarly, marketing paragraphs did not uniformly highlight the GMO nature of the flowers. Implications for the next generation of floral designers demonstrate that, with the exception of students in 2005–06, most would sell both GMO and non-GMO flowers with a majority of shops clearly identifying GMOs.

The Nicotiana tabacum transmitting tissue is a highly specialized file of metabolically active cells that is the pathway for pollen tubes from the stigma to the ovules where fertilization occurs. It is thought to be essential to pollen tube growth because of the nutrients and guidance it provides to the pollen tubes. It also regulates gametophytic self-incompatibility in the style. To test the function of the transmitting tissue in pollen tube growth and to determine its role in regulating prezygotic interspecific incompatibility, genetic ablation was used to eliminate the mature transmitting tissue, producing a hollow style. Despite the absence of the mature transmitting tissue and greatly reduced transmitting-tissue-specific gene expression, self-pollen tubes had growth to the end of the style. Pollen tubes grew at a slower rate in the transmitting-tissue-ablated line during the first 24 h post-pollination. However, pollen tubes grew to a similar length 40 h post-pollination with and without a transmitting tissue. Ablation of the N. tabacum transmitting tissue significantly altered interspecific pollen tube growth. These results implicate the N. tabacum transmitting tissue in facilitating or inhibiting interspecific pollen tube growth in a species-dependent manner and in controlling prezygotic reproductive barriers.

Phalaris arundinacea L. (reed canarygrass) has become one of the most aggressive invaders of North American wetlands. P. arundinacea is native to temperate N. America, Europe, and Asia, but repeated introductions of European genotypes to N. America, recent range expansions, and the planting of forage and ornamental cultivars complicate the resolution of its demographic history. Molecular tools can help to unravel the demographic and invasion history of populations of invasive species. In this study, inter-simple sequence repeat markers were used to analyze the population genetic structure of European and N. American populations of reed canary grass as well as forage and ornamental cultivars. We found that P. arundinacea harbors a high amount of genetic diversity with most of the diversity located within, as opposed to among, populations. Cluster analyses suggested that current populations are admixtures of two formerly distinct genetic groups.

Mammoth™ ‘Twilight Pink Daisy’ (U.S. Plant Patent 14,455; Canadian Plant Breeders’ Rights Certificate No. 4192) is an interspecific garden chrysanthemum cultivar, Chrysanthemum ×hybridum Anderson (= Dendranthema ×hybrida Anderson) with common names of hardy mum, chrysanthemum, and garden mum. It is a new and distinct form of shrub-type garden mums in the Mammoth™ series with rosy-pink ray florets, a dark “eye” color in the center of the disc florets, frost-tolerant flower petals, and self-pinching growth. This cultivar is a butterfly attractant in the garden. Mammoth™ ‘Twilight Pink Daisy’ is a winter-hardy herbaceous perennial in USDA Z3b–Z9 (Southeast)/Zone 10 (West) with its cushion growth form displaying extreme hybrid vigor, increasing in plant height from 0.46 m in its first year to a shrub of 0.76 to 1.22 m in the second year and thereafter with greater than 3000 leaves/plant. Flowering is prolific, covering the entire plant at full flowering with as many as greater than 3500 flowers in the second year. Chemical abbreviations: ethanol (EtOH), indole-3-butyric acid (IBA).

Collection of wild species is critical to increase crop germplasm gene pools. Gaura coccinea has been identified as an important source of cold tolerance (winter hardiness) for hybridization with non-cold tolerant G. lindheimeri. Identification of species in the wild is often complicated by diagnostic, morphological characteristics that may not be present at the time of collection. G. drummondii, however, can be misidentified as G. coccinea even when using some diagnostic and quantitative traits. Therefore, additional methods of distinguishing between the species are needed. Fifteen populations of both G. coccinea and G. drummondii collected for potential breeding purposes in Texas, California, and Minnesota were used to identify species-specific molecular markers and morphological characteristics. A dendrogram based on randomly amplified polymorphic DNA (RAPD) markers separated the genotypes into two groups, G. coccinea and G. drummondii. One unique RAPD marker was identified in all G. drummondii genotypes, but absent in G. coccinea. Dendrograms based on morphological data separated genotypes into three distinct groups: G. coccinea, G. drummondii, and G. sp. (393-1). Petal/sepal lengths and leaf width were smaller in G. coccinea, while fruit/stipe lengths were smaller in both G. coccinea and genotype 393-1. Cytological analysis of G. coccinea confirmed that most populations were tetraploid (2n = 4x = 28) with one hexaploid (2n = 6x = 42) genotype from Texas (1000-1). G. drummondii were primarily tetraploid (2n = 4x = 28). Occasional triploids were found. These markers, along with screening for cold tolerance, will allow for accurate identification of G. coccinea genotypes for hybridization with G. lindheimeri.

Establishment potential is one of the primary components of invasive species risk assessment. Models that predict establishment of potentially invasive ornamental crops often ignore differences among cultivars and the variability in plant response to site-specific factors. The objective of this study was to determine the extent to which differences among cultivars and habitat characteristics affect establishment of 5 cultivars of ornamental cleome. Experiments were conducted to compare germination, survival, and growth of cultivars in cultivated (gardens) and noncultivated (roadsides and prairies) environments and, in prairies, the effects of competition (low, intermediate, and high). In the first experiment, germination, survival, and growth were recorded in gardens, prairies, and roadsides in four locations in Minnesota. In the second experiment, the effects of competition with resident species were studied in five seed lots from three cultivars in three prairie sites. Additionally, a quantitative description of germination and transplantable seedling quality, when grown under greenhouse production standards, was obtained and compared with results from the cultivated and noncultivated outdoor environments. Germination in greenhouse conditions was significantly greater (78%) than in garden, prairies, or roadsides (< 46%). Mortality was greater in noncultivated than in cultivated environments (3% wk−1 and 1.4% wk−1, respectively). Survival was affected by competition, which reduced population establishment. Cultivar differences were most pronounced at seedling emergence, whereas habitat characteristics were more influential at later stages of the life cycle. Germination and plant height were similar among noncultivated environments. Variability in seedling emergence, survival, and growth in response to cultivar, habitat, and competition are important determinants of establishment potential. Among the cultivars studied, the native cleome, roughseed clammyweed, has a greater establishment potential than the nonnative cleome, spiderflower.

The large genome size of easter lily [Lilium longiflorum (77.1 pg/2C nucleus)], coupled with repetitive DNA sequences, makes it difficult to use molecular techniques to identify or fingerprint lily (Lilium) species, hybrids, and clones. Previous research demonstrated that amplified fragment length polymorphisms could not be optimized for consistency and repeatability to obtain reliable genetic variation assessments of lily species and clones. The objective of this research was to analyze the effectiveness and stringency of intersimple sequence repeats (ISSRs) to determine genetic differences between L. longiflorum ‘Nellie White’ clonal ramet populations from bulb growers over years. DNA from closely related clones of L. longiflorum ‘Nellie White’ included 2002 (n = 11 bulb lots) and 2003 (n = 12 bulb lots). Comparison cultivars and species were also included. Five University of British Columbia (UBC) primers (P808, P810, P811, P814, and P818) that were used produced 56 polymorphic loci. ISSR banding patterns were consistent among three replications within ‘Nellie White’ clonal genotypes. ‘Nellie White’ clones differed significantly within (82%) and among (18%) growers in 2002 and 2003. ‘Nellie White’ clones are not uniform or part of a single ramet population. Principal clades within years separated at Nei's genetic distances (GDs) of GD = 0.6 (growers 2, 4, and 12) to GD = 0.82 (grower 6) in 2002 and GD = 0.51 (grower 4) to GD = 0.78 (grower 14). The most closely related ‘Nellie White’ clones within growers ranged from GD = 0.8 to 0.95 in 2002 and GD = 0.7 to 0.91 for 2003. Five top-performing growers (1, and 3–6) from previous morphological studies and, particularly growers 3 and 5, were in similar clades, cosegregating with phenotypic traits of stem emergence and flowering dates. The lack of a meiotic sieve (Muller's ratchet) may be responsible for the high level of mutational differences present in the ‘Nellie White’ clones and significantly affects the ability of commercial greenhouse growers to produce a uniform easter lily crop, particularly in years when the Easter holiday is early.

Polyploidy represents a useful tool for increasing marketability of floriculture crops. The efficacy of 250 μM colchicine [0.01% (w/v)] as a means of inducing polyploidy in six South African Watsonia species (W. borbonica subsp. ardernei, W. humilis, W. laccata, W. lepida, W. pulchra, and W. vanderspuyiae), as determined through high-resolution flow cytometry, is reported. Exposure to colchicine during imbibition and as 24-, 48-, or 72-h pulse treatments for in vitro-germinated seeds resulted in seedlings with increased ploidy, reaching a maximum of 60% induction after the 72-h pulse treatment. The greatest proportions of induced individuals from both the pre- and post-germination exposure treatments were of mixed ploidy. These mixoploids were induced in five species. Non-chimeric tetra- and octaploids were produced in low frequencies only for W. vanderspuyiae during radicle-pulse exposure of 24 and 48 h. Increasing colchicine exposure at radicle emergence manifested as aberrant phenotypic expression and was typified by a reduction in leaf length and rooting capacity in vitro coupled with overall slowed growth. In vitro regeneration and multiplication is easily achievable for the genus and should allow for the capture and refinement of desirable polyploid tissues.

Miscanthus (Miscanthus sinensis Anderss. [Poaceae]) is an ornamental and invasive grass native to Asia that has naturalized in several areas of the Middle Atlantic United States. Predicting how likely miscanthus is to become invasive in other areas of the US is a concern of ecologists and horticulturists. The objective of this study was to measure the competitive ability of miscanthus with an aggressive native grass, switchgrass (Pancium virgatum L. [Poaceae]), in order to show which grass would be more likely to dominate when the two species were grown together. Although switchgrass is a smaller plant than miscanthus, in this greenhouse experiment it was significantly taller and had more vegetative and flowering culms than miscanthus. Miscanthus however, was a stable competitor and did not significantly change in shoot or root dry weight as 2 and 4 switchgrass plants replaced the respective number of miscanthus plants in each treatment. When miscanthus biotypes from four locations were compared, the Pennsylvania biotype was significantly larger and more competitive with switchgrass than was the Washington, DC biotype. As switchgrass plants were replaced with miscanthus, the shoot and root dry weights of the remaining switchgrass plants increased significantly, showing a higher competitive ability of switchgrass. Despite the fact that switchgrass was more competitive with itself than miscanthus, the highest overall dry weight per treatment contained eight switchgrass plants. Miscanthus showed stable, competitive growth when planted together with switchgrass and it is predicted to likely do the same in a field setting.

Written scientific communication, such as laboratory reports, are important components of undergraduate education within the sciences. Since most Horticultural Science majors offer lecture- and lab-based courses, students often write laboratory reports for many courses across the curriculum and these reports comprise a large percentage of the writing assignments in these classes. Instructors link learning objectives with laboratory reports to reinforce course content. Students have noted inconsistencies across horticulture courses in requirements for laboratory report writing, which often leads to confusion. Thus, development of a grading rubric would improve the continuity of expectations of laboratory report writing and grading within a Horticultural Science curriculum for instructors teaching courses requiring laboratory reports. When focusing just on laboratory writing in the curriculum, surveys and interviews indicated that a disconnect exists between what instructors expect of their students and what the stated learning outcomes were for their courses. Student’s ability to analyze results was seen as both a strength and weakness, as reported from faculty responses. In lower division courses, analyzing results from student’s experiments was a weakness while in upper division courses faculty responses were mixed as to whether students had the skills to sufficiently analyze results from their experiments. When a grading rubric was trialed, students indicated that use of the same rubric in other Horticultural Science courses would demystify the process of conducting research and communicating it effectively in laboratory reports. For this work to expand, one or more standard rubrics need to be developed for use by Horticultural Science courses within an institution to enhance our students’ abilities to become competent writers in this form of scientific communication. A baseline rubric for courses at the 3000 level was developed to serve as a template to further this process.

Historically the horticultural industry has transformed the US landscape through intentional cultivar introductions and unintentional introductions of weeds, insects and plant diseases. While it has been demonstrated that the horticultural industry, in particular the ornamental subsector, is an important vector for the introduction and dispersal of invasive species, known invasive plants continue to be sold while new cultivars are introduced at an ever increasing rate. This study examines the horticultural trade as a vector for invasive species, its agents, and characterizes the complexity of the distribution channel. Numerous factors have contributed to the recent expansion in marketed cultivars, including technological, industry growth, and marketing developments. The result has been an increased and sophisticated consumer demand with a corresponding aggressive scouring of the planet for new crops, many of which are introduced into the market without sufficient testing for invasive tendencies. Traditional approaches to invasive horticultural crop control (regulation, self-regulation), which target players in the distribution channel before and/or after cultivar release, have had limited effectiveness and buy-in because these approaches do not address the industry’s complexities and economic incentives. Involvement and education of consumers may provide better oversight outcomes by addressing the moral hazard problem while acknowledging the key characteristics of the industry.

Commercial potted, cut flower, and garden lily production relies on forcing vegetatively-propagated, two- or three-year-old bulbs. Chilling induces stem elongation and more controlled, timely flowering in the wild and in commercial production. Select genotypes of Lilium formosanum lack dormancy and are non-obligate-vernalization-requiring (NV) for flowering. Such NV lilies flower within one year from seed. The objective of this study was to determine the inheritance of NV within select L. formosanum. Twenty-three families were generated from nine parents (6 NV, 3 obligate-vernalization-requiring [OV]). Segregation for NV:OV fit a model for NV being controlled by two genes, hereby named VER1 and VER2. A dominant allele at either locus confers the NV phenotype. For inheritance of NV, VER1 and VER2 parallels the spring/winter flowering habit and VRN1 genes of wheat. VER2 has less penetrance than VER1, and earlier stem emergence among families segregating for VER1 and VER2 suggests epistatic gene action. NV l...

‘Bailer’ (Endless Summer™) is a new, pink- or blue-flowered hydrangea that flowers on new wood continuously throughout the growing season. It is also winter-hardy in northern, temperate climates (USDA Z4). Use of Endless Summer as a florist's potted hydrangea would provide consumers with a dual-use product (flowering potted plant, landscape shrub). The objectives were to determine if Endless Summer could be forced as a florist's hydrangea using two forcing regimes (immediate, standard), two soil pH regimes, and two pinching treatments. ‘Merritt Supreme Pink’ (pink), ‘Blue Danube’ (blue), and Endless Summer (blue, pink) were forced under immediate (no cold treatment, short- and long-day photoperiods) and standard (6 weeks cold, 4 °C to overcome dormancy) conditions. Since commercial liners were not yet available, cuttings of Endless Summer were used in the immediate forcing experiment. Days to visible flower bud, first color, full flower were recorded, as well as height, no. of branches, no. of flowers, and flower size. In the immediate forcing experiment, only Endless Summer produced flowers. Cultivars differed significantly ( P

The use of related species to integrate important traits into cultivated crops is a common practice in plant breeding. Gaura coccinea and, potentially its derived species Gaura drummondii , could be donor species for introgressing cold tolerance into non-hardy G. lindheimeri . However, cold tolerance and acclimation has not been studied in these species, so protocols for determining these traits are required. The objectives of this study were to determine the relative cold tolerance of G. coccinea , G. drummondii and whether short day photoperiod is involved in cold acclimation. G. drummondii from Texas, USA and G. coccinea from Minnesota and Texas, USA were subjected to freezing tests using whole plant or electrolyte leakage after natural acclimation or non-acclimation conditions. Minnesota genotypes were able to withstand colder temperatures (−12 °C) than Texas genotypes (−9 °C). Acclimation capacity was determined for whole plant and electrolyte leakage assays using three different plant organs—stem, crown, and rhizome. Underground rhizomes were the best predictors of cold tolerance, however they were difficult to obtain. Stem sections of G. drummondii (Texas) and G. coccinea (Minnesota and Texas) were used to determine a shift in acclimation under short days. The Minnesota G. coccinea genotypes demonstrated greater cold tolerance after 3 weeks of short days while Texas G. coccinea , G. drummondii genotypes did not change even after 5 weeks.