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The game-show format, used recurrently in an undergraduate-level, introductory plant propagation course, fostered a friendly, competitive incentive for students to master facts and concepts critical to understanding processes in plant physiology. Because student teams, rather than individuals, served as the contestants in each game, and because game points were never translated into grade points, participants and observers learned from and enjoyed the exercises without anxiety. Propagation-specific clues and questions were prepared for “Wheel of Fortune,” “Win, Lose, or Draw,” and other games. These were followed up at the end of each semester with several play-off rounds of a plant propagation variant of “Jeopardy!”, which served as an excellent means of course synthesis and review of key concepts. The format allowed for liberal use of humor as an effective pedagogical tool and resulted in the hands-on contributions of former students in construction of new game quizzes and puzzles for subsequent semesters.
Use of a liquid media during micropropagation has promoted improved proliferation and rooting response in several species. In this experiment, a double phase system (a combination of liquid and agar solidified medium) was applied to three cultivars of miniature roses (Rosa chinensis var. minima) to determine the effects on shoot quality and subsequent ex-vitro rooting. Applications of liquid media to the surface of agar solidified media were made at 0, 2, and 4 weeks. Evaluation via computerized image analysis after eight weeks of proliferation revealed equal or greater values for shoot length, area and weighted density (equivalent to fresh weight) for cultures receiving overlay, regardless of timing, compared to the solid media control. Additionally, application of a liquid overlay improved rooting response by up to 20% over the control and resulted in a tendency for a greater number of roots of greater length and area than the treatment without liquid media overlay.
Day-neutral strawberry (DNS) production is increasing in the Upper Midwest because of its extended harvest season and greater yield over June-bearing cultivars. However, the longer season increases fruit exposure to the invasive spotted-wing drosophila (Drosophila suzukii; SWD), which threatens the production of small fruits and berries, particularly in organic systems. Numerous pest management tactics have been developed for SWD in recent years; however, relatively few studies have investigated the impact of SWD on DNS. Organic DNS growers need information regarding which management strategy is most effective when compared directly. To address this knowledge gap, we established a 2-year controlled field experiment with organic DNS. We applied treatments that correspond with techniques that local growers reported using or that have shown promise for organic raspberries, including increased harvest frequency, botanical-based repellents, and weekly rotations of organic insecticides, which we compared with an untreated control. We hypothesized that noninsecticidal SWD management strategies would result in fewer SWD eggs per berry and a lower proportion of infested berries compared with those associated with an untreated control. We also hypothesized that noninsecticidal management strategies would be as effective and cost less than organic insecticide applications. We collected data regarding labor hours, direct costs, strawberry yield, and SWD infestation in experimental plots on certified organic land in Minnesota in 2022 and 2023. An average of 33% of strawberries contained SWD eggs. The experimental treatments showed inconsistent effectiveness for reducing infestation compared with that of the untreated control plots and had no effect on marketable plant yield over the 2-year period. Thus, the added labor expense of these pest control treatments yielded net returns that were 17% to 21% below the control. Labor-saving alternatives like exclusion netting or postharvest cold treatments, which reduce fruit pest exposure and egg viability without harming nontarget insects, may offer more cost-effective solutions for managing SWD in organic DNS.
The only method for large scale production of pure hybrid seed in Zinnia elegans involves the use of male sterile individuals. The male sterile trait, however, is a three gene recessive which at best produces only 50% male sterile progeny from seed. Since no method of clonal propagation is available, seed-produced female lines require labor intensive field roguing to insure removal of all normal flowered individuals. Clonal micropropagation was investigated as a means of mass producing male steriles for use as female lines. Sterilization procedures were developed for seed and axillary bud explants. Shoot proliferation media containing various levels of BAP, 2ip, and kinetin were screened using in vitro germinated seedling explants of the inbred line `Orange Starlight'. Microshoots demonstrated a high rooting percentage after 2 weeks on basal medium without growth regulators. Plantlets were easily acclimated in 1 to 2 weeks in a high humidity environment. In vitro derived plants of identified male sterile plants were phenotypically evaluated as to their suitability for use in field production.
The only method for large scale production of pure hybrid seed in Zinnia elegans involves the use of male sterile individuals. The male sterile trait, however, is a three gene recessive which at best produces only 50% male sterile progeny from seed. Since no method of clonal propagation is available, seed-produced female lines require labor intensive field roguing to insure removal of all normal flowered individuals. Clonal micropropagation was investigated as a means of mass producing male steriles for use as female lines. Sterilization procedures were developed for seed and axillary bud explants. Shoot proliferation media containing various levels of BAP, 2ip, and kinetin were screened using in vitro germinated seedling explants of the inbred line `Orange Starlight'. Microshoots demonstrated a high rooting percentage after 2 weeks on basal medium without growth regulators. Plantlets were easily acclimated in 1 to 2 weeks in a high humidity environment. In vitro derived plants of identified male sterile plants were phenotypically evaluated as to their suitability for use in field production.
High tunnels are an important season extension tool for horticultural production in cold climates, however maintaining soil health in these intensively managed spaces is challenging. Cover crops are an attractive management tool to address issues such as decreased organic matter, degraded soil structure, increased salinity, and high nitrogen needs. We explored the effect of winter cover crops on soil nutrients, soil health and bell pepper (Capsicum annuum) crop yield in high tunnels for 2 years in three locations across Minnesota. Cover crop treatments included red clover (Trifolium pratense) monoculture, Austrian winter pea/winter rye biculture (Pisum sativum/Secale cereale), hairy vetch/winter rye/tillage radish (Vicia villosa/S. cereale/Raphanus sativus) polyculture, and a bare-ground, weeded control. Cover crop treatments were seeded in two planting date treatments: early planted treatments were seeded into a standing bell pepper crop in late Aug/early September and late planted treatments were seeded after bell peppers were removed in mid-September At termination time in early May, all cover crops had successfully overwintered and produced biomass in three Minnesota locations except for Austrian winter pea at the coldest location, zone 3b. Data collected include cover crop and weed biomass, biomass carbon and nitrogen, extractable soil nitrogen, potentially mineralizable nitrogen, microbial biomass carbon, permanganate oxidizable carbon, soil pH, soluble salts (EC), and pepper yield. Despite poor legume performance, increases in extractable soil nitrogen and potentially mineralizable nitrogen in the weeks following cover crop residue incorporation were observed. Biomass nitrogen contributions averaged 100 kg·ha−1 N with an observed high of 365 kg·ha−1 N. Cover crops also reduced extractable soil N in a spring sampling relative to the bare ground control, suggesting provision of nitrogen retention ecosystem services.
Results suggest that sand topdressing was more consistent at reducing dollar spot (Clarireedia jacksonii) in fairway turfgrass more so than rolling. This practice could be an effective cost-saving alternative to reduce frequent fungicide applications. Research was conducted from 2011 to 2014 on a simulated golf fairway and examined dollar spot severity responses in a mixed-stand of creeping bentgrass (Agrostis stolonifera) and annual bluegrass (Poa annua ssp. reptans) to sand topdressing and rolling. Treatments consisted of biweekly sand topdressing, rolling at three frequencies (one, three, or five times weekly), a control, and three replications. Infection was visually estimated. Sand topdressing significantly (P < 0.05) reduced disease up to 50% at the peak of the dollar spot activity in 2011, 2013, and 2014. Results on the effects of rolling on dollar spot were inconsistent.