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Seed-propagated lilies have the potential to revolutionize Easter lily production, eliminating clonal disease transmission, costly production and shipping. Five F₁ interspecific hybrids, Lilium × formolongo (L. longiflorum × L. formosanum), were evaluated to establish an initial forcing schedule. The hybrids included `Raizan Herald', `Augusta F1', `Raizan No. 1', `Raizan No. 2', and `Raizan No. 3'. Two hundred seeds/hybrid were sown in early July in plug trays. Ten weeks after sowing, seedlings were transplanted into 3-inch pots. At the 20-week stage, the seedlings were repotted into 6-inch standard pots for the final production phase. All hybrids had low germination rates (<20%). Hybrids were grown under two photoperiod treatments (short, long days) at 21 °C with n = 10 reps/hybrid/treatment. Plants were evaluated for no. days to visible bud, leaf unfolding rate, final plant height, leaf number, bud count, flowering dates, and the no. of shoots/bulb. Ten weeks after sowing, hybrids had one to four leaves/plant. At 20 weeks, the leaf number had increased to as many as 40. Despite the lack of a cold treatment, most hybrids initiated flower buds. Visible bud date occurred as early as 20 weeks after sowing. Photoperiod had no effect on leaf number, stem height, and flower bud initiation. Plant height exceeded 15 inches by week 16 in most hybrids, indicating the need for plant growth regulator applications. The next steps in product development for seed-propagated Easter lilies will be outlined.

In production classes, students often commence the class by learning complicated crop-specific production cycles. Rarely are they afforded the opportunity of spending several class periods to first understand the major differences between commercial crops for production time, labor input, and market share. A cooperative learning exercise was created for the first week of lectures in potted plant production class (Hort 4051) at the Univ. of Minnesota (n = 18 students). Students were assigned to working groups for discussion and synthesis of the assignment. One week later, each group turned in their recommendations and one lecture session was devoted to in-class discussion of their answers. The exercise was in the form of a memo from a commercial company, Floratech, addressed to the students as the newly hired potted plant production specialists. In the memo, a graphical summary was presented of 13 major and minor potted crops, contrasting total production time, labor input, and market share for each crop. As production specialists, the student's primary task was to interact with all staff (other students role-playing various positions within the company) to answer the following question: “What is the most realistic, cost-effective location on the graph that Floratech should aim to move all crops?” Group discussions, both within and outside of class, focused on the noticeable trends depicted by the graph and the limiting factors that prevented crops from moving to the ideal location. Growers and breeders were quizzed on what factors kept each crop in the specific locations on the graph. The majority of student chose the midpoint of the graph as the best location. The exercise successfully peaked student's awareness of crop differences and the limiting production factors. Throughout the semester, students referred back to this graph to pinpoint the location for each crop covered.

Abstract

Reclassifications of the genus Chrysanthemum (10, 11, 13-15, 18, 22), accepted by most botanists and taxonomists for almost a decade, have not been brought to the attention of horticulturists. Of special concern is the correct scientific name of the garden and greenhouse chrysanthemums, currently integral components of national and international floricultural trade.

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.

Cleome hassleriana is an ornamental garden plant introduced from South America and naturalized in eastern United States with tendencies to reseed primarily in gardens. The objectives of this research were to determine (1) if C. hassleriana cultivars can germinate in Minnesota prairies and roadsides, (2) if germination in cultivated environments reflect germination in non-cultivated environments, and (3) if there are differences among cultivars across environments, with some cultivars germinating well in cultivated habitats and poorly in non-cultivated habitats. In June 2003, 135 seeds from each of four cultivars (Queen Rose, Queen White, Sparkler Rose and Sparkler White) were planted in each of 4 gardens and 8 non-cultivated habitats (4 prairies and 4 roadsides). Germination and survival was recorded once weekly for four weeks. Cleome seeds germinated in Minnesota gardens, prairies and roadsides. By day 14, the proportion of germinated seedlings was significantly greater in gardens (30.5%) than in prairies (1.4%) and roadsides (0.9%). Sparklers had significantly greater germination than Queens in the prairies. The best performing cultivar in the garden (Queen White, 29%) was different than the best performing cultivar in the prairies and roadsides (Sparkler Rose, 1.4% and 1.2% respectively), suggesting that germination in non-cultivated habitats may not reflect germination in the field. Cultivars varied in their ability to germinate in cultivated and non-cultivated environments.

Since 1924, the Univ. of Minnesota herbaceous perennial breeding program has released n = 84 garden chrysanthemums (Dendranthema grandiflora). Recent breeding objectives have focused on development of non-destructive phenotypic markers and laboratory freezing tests for continued selection of cold-tolerant Dendranthema, Gaura, and other herbaceous perennial flowers. Such methods have become critical to flower breeding programs during periods of above-average winter temperatures and minimal snow cover. Two different laboratory freezing tests were evaluated for their effectiveness in determining cold tolerance. Acclimated crowns of n=6 hardy and non-hardy garden chrysanthemum genotypes were used in Omega Block (detached, emergent rhizomes) and chamber (intact crowns with emergent/non-emergent rhizomes) freezing test methods. Comparative winter survival in the field was monitored over locations and years. Cold tolerance was assessed at 0 °C to -12 °C with varying ramp and soak time periods. LT₅₀ temperatures and number of living emergent rhizomes were determined. Rhizome quality at 1 cm, 3 cm, and 5 cm depths was rated on a 0 (dead) to 5 (undamaged) scale. The chamber freezing method was the most powerful to discern LT₅₀ values. Cold tolerant genotypes included `Duluth' and 98-89-7 (LT₅₀ = -12 °C). Three genotypes had intermediate cold tolerance (LT₅₀ = -10 °C) and one genotype was not cold tolerant (LT₅₀ = -6 °C). Cold-tolerant genotypes also had significantly higher regrowth ratings for rhizomes at 1cm and 3cm depths. Future research will use the chamber freezing method to assay the inheritance of winter hardiness in intact crowns of segregating populations.

Greenhouse and garden chrysanthemums are quantitative short-day (SD) plants for flower bud initiation (FBI) and qualitative (obligate) SD plants for flower bud development (FBD). Continuous or intermittent application of red light in the middle of the dark period (night), inhibits FBI. The chrysanthemum breeding program has been selecting for day-neutral (DN) types, i.e. that will undergo FBI and FBD under any photoperiod. The inheritance of DN was studied using six cultivars (n = 2 SD types, n = 4 DN types) that were crossed in a complete diallel over two crossing periods. Pollinations were replicated and ovules were counted. Histograms of self and cross seed set showed a distribution from 0% to 100%, with the majority of pollinations below 30%. Mean self seed set (2.6%) was less than the mean cross seed set (32.8%), indicating the presence of a self incompatibility system. Parents and F₁ progeny were grown under LD conditions (red light, night interruption, 2200-0200 HR) and high temperatures (30 °C day/25 °C night, to screen for heat delay insensitivity). F₂ progeny could not be generated due to self incompatibility. The fraction of flowering: non-flowering progeny and the number of days to first flower was recorded on the flowering individuals for comparison with the parents. Due to small progeny numbers, reciprocal crosses were bulked prior to Chi-square tests (1:1, 3:1, 1:3). The number of days to first flower ranged from 27 to 93+ in all progeny with significantly earlier and later outliers present. Most Chi-square tests were not significant, indicating that the inheritance of DN and heat delay insensitivity are not controlled by a single gene. Additive and epistatic effects may also be present.

A majority of commercial Lilium hybrids and species do not flower the first year from seed or scales due to an obligate vernalization requirement. The Formosa lily (L. formosanum) is a unique species within the genus Lilium because some genotypes flower from seed the first year without vernalization. The objective of this study is to determine the inheritance of stem emergence, which culminates in flowering, in seed-propagated families without vernalization. Nine L. formosanum genotypes, selected from six populations for obligate or non-obligate vernalization for flowering, were intermated to generate 23 families with 104 seedlings per family. Families were grown in a randomized complete-block design at 21 °C (day/night) and data collected were seedling mortality, stem emergence or rosetting without vernalization, and weeks to emergence. At the end of 44 weeks, rosetted genotypes were vernalized for 8 weeks (4 °C); 100% emerged. We propose this trait is controlled by two genes. For flowering without vernalization to occur, there needs to be at least one dominant allele at one of the loci. Locus Ver ² has less penetrance than Ver ¹. Families segregating for dominant alleles at both Ver ¹ and Ver ² emerged sooner (34.2 weeks) than those segregating for a dominant allele at only Ver ¹ (36.1 weeks) or Ver ² (37.6 weeks). Identification of these genes can aid in the development of uniform, fast-flowering L. formosanum hybrids as well as aid in the introgression of this trait into standard commercial lily classes.

It should be possible to maintain horticultural clones unchanged forever through asexual generations, as commercial propagators and clonal repositories maintain clonal integrity, disease-free stock plants, or remove mutations. However, unintentional selection for nonhorticultural traits could still be occurring. Accumulations of such traits would be due to the operation of Muller's ratchet and include fertility losses, increases in virus titer, and stunted growth habit. In chrysanthemums, Dendranthema grandiflora. clones separated from sexual cycles for generations become increasingly sterile. Seed set across years, using coefficients of crossability (FCC/MCC), was examined for garden clones (forced through sexual cycles annually) and greenhouse clones (asexual cycles only). Garden clones 40 years old (54-101-11) had only depressed levels of fertility. In other cases (77-AM 3-17), the ratchet was reversed >1 sexual cycle. Greenhouse clones were often completely sterile since their propagation is primarily asexual.

The prostrate plant habit may be an important new trait for the garden chrysanthemum [Dendranthema ×grandiflora Tzvelv. (=Chrysanthemum ×morifolium Ramatuelle)] market. Fifteen prostrate and non-prostrate genotypes were evaluated in production trials, using Regular and Fast Cropping systems. At flowering, the following traits were evaluated: days to flowering (first, 50%, 100%), flowering duration, pot coverage, plant uniformity, and salability. Salability was measured with consumer evaluations. Genotypes differed significantly for days to first and 100% flowering, flowering duration, plant height, plant width, and plant uniformity. Cropping systems were significantly different for days to first and 100% flowering. `Snowscape', a semi-prostrate day-neutral cultivar, was earlier than all other genotypes for days to first flower. It also had the longest flowering duration. `Snowscape' would be the best genetic source for creating early, continual flowering cultivars. Most prostrate genotypes were as early as commercial cultivars. Genotype 90-275-27 was significantly shorter (prostrate) than all other genotypes and would be the best genetic source for prostrate plants. Genotypes 95-169-8, 92-237-9, 95-157-6, 95-169-10, 90-275-27, and `Snowscape' had the most acceptable plant width for shipping. Plant uniformity of 95-169-10 and 95-169-8 matched that of `Debonair' and `Spotlight', all of which were significantly more uniform than the other genotypes. The least uniform prostrate was 95-331-10. `Snowscape' had the highest (best) index of traits ranking and was significantly better than all other genotypes. Consumer evaluations were highest for non-prostrate cultivars.