Melatonin plays an important role in plant resistance to stress. The role of melatonin in the propagation of plant tissue, such as rhizome proliferation, differentiation, and seedling rooting in Cymbidium species, remains unknown. In this study, we selected C. goeringii and C. faberi as experimental materials and attempted to understand the effect of melatonin on this process. We found that 1.0 μM melatonin was beneficial for rhizome proliferation of C. goeringii, with a proliferation rate of 5.52. In terms of C. faberi, the highest proliferation rate of 8.29 was observed in the medium with 0.5 μM melatonin. In proliferation, the cut rhizome of C. goeringii is more likely to cause browning phenomenon than that of C. faberi. The addition of melatonin can significantly inhibit the browning phenomenon and improve the survival rate of C. goeringii rhizome. The highest number of shoot buds per explant (3.11 after 60 days) was observed in the medium with 1.0 μM melatonin. The number of shoot buds per explant (3.28 after 60 days) was significantly higher for C. faberi in the medium with 5.0 μM melatonin than that for the control. Furthermore, culture medium incorporated with 1.0 μM of melatonin had the best comprehensive effect of seedling height and root number and length of C. goeringii. By contrast, 0.5 μM melatonin significantly promoted root elongation of C. faberi, reaching 1.77 cm, whereas it was 0.28 cm in the control. We demonstrated that melatonin in specific concentrations effectively promote rhizome proliferation, differentiation, and seedlings rooting in the rapid propagation of C. goeringii and C. faberi.
Weiting Huang, Xiaoyan Huang, and Zhongming Fang
Michael J. Havey
The amounts and types of epicuticular waxes on onion (Allium cepa) leaves affect feeding damage by onion thrips (Thrips tabaci), a serious insect pest of onion. This study used gas chromatography mass spectrometry (GCMS) to measure amounts of epicuticular waxes on foliage of two plants from each of 50 plant introductions (PI) and inbred lines with high (waxy) and low (glossy) amounts of wax. Wax amounts on leaves of the same plants were measured twice (once in the greenhouse and once after moving plants outside) and were significantly (P < 0.01) correlated; however, wax amounts on leaves of plants grown in the greenhouse were approximately twice that of the same plants grown outside. Hentriacontanone-16 (H16) was the predominant wax on leaves of all PIs except PI 289689, and amounts of H16 were significantly correlated with amounts of fatty alcohols and total wax. Five plants from 17 of the PIs were grown in the greenhouse, wax amounts measured using GCMS, and results were significantly correlated with earlier evaluations. Results indicate that measurements of waxes on onion foliage should occur under protected conditions to better characterize phenotypic variation, and selection of higher amounts of waxes other than H16 may be effective toward the development onions suffering less thrips damage.
Andre Luiz Biscaia Ribeiro da Silva, Marcos Fabricio Landim de Barros, Wheeler Foshee, Joara Secchi Candian, and Juan Carlos Diaz-Perez
Parsley seeds are known for nonuniform and long germination; consequently, vegetable nurseries commonly use priming techniques to improve the production of parsley seedlings. The objectives of this study were 1) to characterize the imbibition curve of parsley seeds, 2) to evaluate the effect of different priming agents on parsley seedling production, and ultimately 3) to compare priming techniques for emergence and vigor of parsley’s seedlings, thus providing an optimal priming strategy for parsley seedling production. Using three priming agents—water (seeds imbibed for 24, 48, 72, and 96 hours), polyethylene glycol 6000 (PEG6000) (seeds imbibed at –0.5, –1.0, –1.5, and –2.0 MPa for 29, 58, 87, and 116 hours), and gibberellic acid (GA) (seeds imbibed at 0.5, 1.0, 1.5, and 2.0 g·L−1 a.i. of solution for 15, 30, 45, and 60 minutes), and two parsley cultivars (Krausa and Titan), three experiments evaluated parsley seedling parameters, including emergence speed index (ESI) and total emergence (TE) in a complete randomized block design (n = 4) each. In Expt. 1 (hydropriming), increasing water imbibition time (IT) reduced ESI on both parsley cultivars. In addition, the TE quadratically reduced with the increase of water IT. In Expt. 2 (osmopriming), there was no significant main effect or interaction of treatments on ESI. Regardless of PEG6000 concentration, the TE had a linear increase with the increase of IT for cultivar Krausa but not for cultivar Titan. In Expt. 3 (hormonal priming), there was a significant increase in ESI and TE with the increase in GA rate. Ultimately, strategies for analysis of best priming were water at 24 hours of IT, PEG6000 at –2.0 MPa for 116 hours of IT, and GA at 2.0 g·L−1 a.i. of solution for 15 minutes of IT. Once compared with an untreated seeds treatment, priming strategies of water imbibition for 24 hours and PEG6000 at –2.0 MPa for 116 hours had the highest ESI and TE.
Chen Lian, Yuyan Li, Haiying Li, Yaxin Zhao, Juan Zhou, Sijie Wang, Jingran Lian, and Yan Ao
Hao Wang, Yuan-hao Su, and Jian-ping Bao
Korla fragrant pear is the main pear variety and one of the most famous fruits in Southern Xinjiang. The use of protective nets in fruit tree production is increasing; however, the cultivation of Korla fragrant pear in Xinjiang has yet to be developed. Therefore, we used the ground and underground microclimate anti-hail network and open-air conditions to determine the fruit quality and measure tree growth-related indicators. Additionally, we subsequently recorded the average yield of fragrant pear fruits to evaluate their economic value under the anti-hail net and open-air environments. Furthermore, we performed a correlation analysis to explore the correlation between environmental factors and fruit quality and growth under the two conditions. We found that the anti-hail net cover provided a conducive environment for the vegetative and reproductive growth of trees. Under similar fruit quality conditions, the average yield was markedly higher under the anti-hail net environment than under the open-air environment. Furthermore, the economic benefit under the anti-hail net was higher for all factors, except for the average facility cost during the previous year, than that under the open-air condition.
Neil O. Anderson
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.
Sarah Cato, Amanda McWhirt, and Lizzy Herrera
Misinformation relating to horticulture can spread quickly among laypersons. Although some misinformation may be harmless, such as the myth that bell pepper (Capsicum annuum) fruit can be either male or female, other misinformation is generated to sway consumer decisions. The demand from Cooperative Extension Service (CES) agents for support to combat the spread of horticultural misinformation, horticulture specialists at the University of Arkansas System Division of Agriculture Cooperative Extension Service (UACES) created a “Horticulture Fact or Fiction” series of blog posts that targeted common horticulture myths with science-based explanations and used graphics interchange format (GIFs) to promote the blog posts on social media. The integrated social media campaign was shared on the authors’ UACES Horticulture social media accounts and by eight UACES agents during 2021. The effort reached 13,397 social media users, and the blog posts had a total of 45,544 pageviews. Although social media was not the major driver of traffic to the blog post series, GIF-based outreach on social media did direct more than 1000 additional users to the blog posts. Through this integrated approach of using social media and GIFs shared by both specialists and CES agents, we were able to connect a large number of stakeholders to research-based content, resulting in higher average traffic to our webpage-based blogs than the average UACES webpage. This type of integrated approach using multiple online means of communication including GIFs, blogs, and social media to create a toolkit of resources for CES agents may be useful for extension professionals targeting stakeholders online.
Catherine G. Campbell, Jorge Ruiz-Menjivar, and Alia DeLong
Florida, like much of the southeastern United States, is rapidly urbanizing. With this urbanization, there is an increasing interest in commercial urban agriculture (CUA) as an important sector for agriculture in the state. The U.S. Department of Agriculture Census of Agriculture does not report data about CUA operations, thus limiting the knowledge about the status of CUA operations regarding basic features such as farm size, operator demographics, production systems, sources of revenue, barriers to business operations and profitability, and future opportunities for development. Because previous research has found differences in urban farmers’ demographics and their perceptions of barriers and opportunities, the purpose of this research was to characterize CUA operations in Florida and to understand the urban farmers’ perceptions of the primary needs, barriers, and opportunities for developing CUA, as well as CUA operators’ informational needs and preferred informational formats. We performed a cluster analysis to identify salient groups of urban growers in Florida to identify subgroups based on shared characteristics that revealed three distinct groups of urban farmers with differing perceptions of barriers, opportunities, informational needs, and preferred informational formats.
Sandhya Neupane and Fulya Baysal-Gurel
Phytophthora root rot, caused by Phytophthora nicotianae Breda de Haan, is one of the destructive diseases of boxwood (Buxus sempervirens L.) and can affect all growth stages of field- and container-grown boxwood plants. Management is a problem and is only possible through an integrated approach. In this study, the efficacy of fungicides, biofungicides, host-plant defense inducers, and fertilizer were evaluated to manage Phytophthora root rot of boxwood. The objective of this experiment was to develop fungicide and biofungicide recommendations for Phytophthora root rot management in boxwood production. Field and greenhouse experiments were conducted in 2019 (Trial 1) and 2020 (Trial 2). The field experiment was arranged in a completely randomized design with four plots per treatment with five single ‘Green Velvet’ boxwood plants per plot. The greenhouse experiment was arranged in a completely randomized design with five single ‘Green Velvet’ container-grown boxwood plants per treatment. Plots/containers were inoculated with P. nicotianae grown on rice grains. Plant growth data such as height and average width were recorded at the beginning and end of the experiments. Total plant fresh weight and root fresh weight were recorded at the end of the experiments. Roots were assessed for root rot disease severity using a scale of 0% to 100% roots affected. Treatments used in both experiments were fungicides—ametoctradin + dimethomorph, fluzapyroxad, mefenoxam, oxathiapiprolin, pyraclostrobin, pyraclostrobin + boscalid; host-plant defense inducers—aluminum tris-drench, aluminum tris-foliar, potassium salts of phosphoric acid; biofungicides—Trichoderma harzianum Rifai strain T-22 + Trichoderma virens strain G-41, Bacillus amyloliquefaciens Priest; fertilizer—water-soluble nitrogen (nitrogen 5%) and soluble potash; and combination of water-soluble nitrogen, soluble potash, and T. harzianum Rifai strain T-22 + T. virens strain G-41. All treatments were drench applied except one of the aluminum tris, which was applied as foliar. The controls were nontreated, inoculated and nontreated, and noninoculated boxwood plants. In the greenhouse experiments, treatments that effectively reduced disease severity were pyraclostrobin, ametoctradin + dimethomorph, and oxathiapiprolin. In the field experiments, treatments such as pyraclostrobin, oxathiapiprolin, mefenoxam, fluzapyroxad, and combination of water-soluble nitrogen (nitrogen 5%), soluble potash, and T. harzianum Rifai strain T-22 + T. virens strain G-41 effectively reduced Phytophthora root rot severity. Oxathiapiprolin and pyraclostrobin are the chemical fungicides that were effective in both field and greenhouse experiments.
Eric T. Stafne
Passiflora incarnata L., commonly known as maypop, is a wild passion fruit native to many areas of the eastern and southern United States where the climate ranges from subtropical to temperate. Although P. incarnata has had little attention paid to it for breeding purposes, it could be used in breeding for fruit production and possibly contribute cold hardiness genes in combination with other Passiflora species. The study was performed in 2018, 2019, and 2021 at the Mississippi State University South Mississippi Branch Experiment Station in Poplarville, MS, United States. Passiflora propagules were collected from various locations: Florida (FL), Illinois (IL), Mississippi (MS), Missouri (MO), and Oklahoma (OK). Of the 122 flowers across the five P. incarnata genotypes from differing locations, none of them produced a fruit or had any indication of successful or partially successful fertilization when selfed, indicating strong self- incompatibility. If self-compatibility does exist in nature, it is likely to be rare. However, certain combinations of P. incarnata from different locations produced successful fruiting, including IL × MO (52% success), FL × MO (85%), FL × OK (80%), MS × OK (40%), MO × IL (50%), MO × OK (40%), and OK × MO (80%). The differences across provenances show that incompatibility exists within P. incarnata but can depend on location. Overall, fruit weight, fruit size, and soluble solids content measured in this study were similar to and, in some cases, greater than those previously reported. These differences help to illustrate the diversity within P. incarnata and the still-untapped potential for breeding improvements. The problem of self-incompatibility is complex and there is much to learn about how Passiflora species, especially P. incarnata, function. Much of the U.S. domestic market is not familiar with passion fruit, especially as a table fresh product. This could be a barrier to adoption, but it could also prove to be an opportunity to create a niche within the present market and expand it. Although maypop fruit quality is not equal to that of Passiflora edulis Sims, selecting superior wild genotypes with desirable attributes to be used in future intra- and interspecific breeding is possible based on the results of this study.