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Open access

Maegen Lewis, Melanie Stock, Brent Black, Dan Drost, and Xin Dai

The demand for locally grown, specialty cut flowers is increasing and now includes nontraditional regions for production, such as the U.S. Intermountain West. The objective of this study was to evaluate snapdragon (Antirrhinum majus L.) as a cool season, cut flower crop in northern Utah, where the high elevation and semiarid climate result in a short growing season with strong daily temperature fluctuations. High tunnel and field production methods were trialed in North Logan, UT (41.77°N, 111.81°W, 1382 m elevation) with cultivars ‘Chantilly’, ‘Potomac’, and ‘Rocket’ in 2018 and 2019. Each year, five to six transplant timings at 3-week intervals were tested, beginning in early February in high tunnels and ending in late May in an unprotected field. Stems were harvested and graded according to quality and stem length. High tunnels advanced production by 5 to 8 weeks, whereas field harvests continued beyond the high tunnel harvests by 2 to 8 weeks. High tunnels yielded 103 to 110 total stems per m2 (65% to 89% marketability), whereas field yields were 111 to 162 total stems per m2 (34% to 58% marketability). Overall, production was the greatest with March transplant timings in the high tunnels and mid-April transplant timings in the field. ‘Chantilly’ consistently bloomed the earliest on 4 and 6 May each year, ‘Potomac’ had the highest percentage of long stem lengths, and ‘Rocket’ extended marketable stem production through July in high tunnels. Selecting optimal transplant dates in the high tunnel and field based on cultivar bloom timing maximizes marketable yields and results in a harvest window lasting 4.5 months.

Open access

Chengyan Yue, Manlin Cui, Eric Watkins, and Aaron Patton

Important financial savings, along with reductions in environmental impact, can be achieved by planting lawns with low-input turfgrass species. Drawing on data from an online survey, this article provides empirical evidence on the factors that influence consumers’ willingness to adopt low-input turfgrasses. We group consumers into two segments: Willing Adopters and Reluctant Homeowners. Regardless of segment, consumers who regard maintenance requirements as more important were more willing to adopt low-input turfgrasses, whereas those who placed a higher value on appearance, were more unlikely to change to a low-input turfgrass, especially for Reluctant Homeowners. We categorized the barriers to adoption as follows: 1) Promotion, 2) Benefits and Accessibility, 3) Peer Effect, 4) Sample, and 5) Information. Our models predict that consumers’ willingness to adopt low-input turfgrass can be significantly increased if the identified barriers are removed. Based on our study, suppliers/retailers should adopt heterogeneous and multiple marketing strategies, such as promoting through multiple channels, informing and advising the public on proper information, providing photos or exhibiting in-store samples, triggering communication between different types of consumers, and providing incentives and improving accessibility, to target different consumer groups.

Open access

Jonathan H. Crane, Pollyana Cardoso Chagas, and Edvan Alves Chagas

Open access

Reagan W. Hejl, Benjamin G. Wherley, and Charles H. Fontanier

Landscape irrigation frequency restrictions are commonly imposed by water purveyors and municipalities to curtail domestic water use and to ensure adequate water supplies for growing populations during times of drought. Currently, published data are lacking concerning irrigation frequency requirements necessary for sustaining acceptable levels of turfgrass quality of commonly used warm-season turfgrass species. The objective of this 3-year field study was to determine comparative turfgrass quality of drought-resistant cultivars of four warm-season lawn species in the south–central United States under irrigation frequency regimes of 0, 1, 2, 4, and 8× monthly. Turfgrasses used in the study were based on previously reported drought resistance and included ‘Riley’s Super Sport’ (Celebration®) bermudagrass [Cynodon dactylon (L.) Pers.], ‘Palisades’ zoysiagrass (Zoysia japonica Steud.), ‘Floratam’ st. augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze], and ‘SeaStar’ seashore paspalum (Paspalum vaginatum Swartz). During each growing season, slightly reduced irrigation volumes and bypassed events resulted from the 8× monthly treatment (34.95 cm, 38.13 cm, and 27.33 cm) compared with the 4× monthly treatment (35.36 cm, 40.84 cm, and 28.70 cm) in years 1, 2, and 3, respectively. For the once weekly treatment, the average fraction of reference evapotranspiration (ETo) supplied by effective rainfall and irrigation during the summer months was 1.22, 0.67, and 0.83 in years 1, 2, and 3, respectively, and was generally adequate to support acceptable turfgrass quality of all warm-season turfgrasses evaluated. Under the less than weekly irrigation frequency, st. augustinegrass and seashore paspalum generally fell to below acceptable quality levels because the average fraction of ETo supplied by effective rainfall and irrigation during the summer months of years 2 and 3 was 0.51, 0.39, and 0.26 for the 2× monthly, 1× monthly, and unirrigated treatments, respectively. Bermudagrass generally outperformed all other species under the most restrictive irrigation frequencies and also did not differ statistically from zoysiagrass. These results show that as irrigation frequency is restricted to less than once per week, species selection becomes an important consideration.

Open access

Binjie Xu, Yongxia Chen, Wangxiang Zhang, and Donglin Zhang

Open access

Killian Melsen, Mark van de Wouw, and Ryan Contreras

The promising possibilities of mutation breeding in ornamental plants have led to a great interest in effective mutagenic treatment protocols for various species. This review discusses mutagenic treatments of a large number of ornamental genera, the advantages and disadvantages of various techniques, and the possibilities of improving the associated protocols. A number of nontargeted mutagenesis methods are available, ranging from chemical treatment with alkylating agents to irradiation with X-rays, gamma rays, and neutron or heavy ion beams at various doses. These are all relatively inexpensive and have been proven to be effective mutagens in a large number of diverse species. Genetic engineering, however, remains mostly impractical for many ornamental breeding operations because of the high cost and lack of knowledge necessary to successfully transform and regenerate ornamental crops. Of the available nontargeted mutagens, irradiation with gamma rays is still the most popular. It provides high consistency compared with chemical mutagens, albeit at a seemingly lower mutagenic efficiency. Changes in the radiation dose rate may increase the efficiency, although chronic irradiation over a longer period causes fewer deleterious mutations than the commonly used acute irradiation protocols. Heavy ion beam irradiation may also provide highly consistent mutation induction at higher efficiencies because of the high particle energy associated with these treatments. There are also opportunities to improve chemical mutagenesis. Although the required knowledge of specific gene functions in many ornamentals is still lacking, combination mutagenesis with ethyl methanesulfontate with genetic screening in a process known as TILLING (Targeting Induced Local Lesions IN Genomes) may lead to a powerful mutation breeding tool in the future. Mutation breeding is still very useful, and many opportunities are available to improve the existing methods.

Open access

Eduardo Esteves, Gabriel Maltais-Landry, Flavia Zambon, Rhuanito Soranz Ferrarezi, and Davie M. Kadyampakeni

The bacterial disease Huanglongbing (HLB) has drastically reduced citrus production in Florida. Nutrients play an important role in plant defense mechanisms and new approaches to manage the disease with balanced nutrition are emerging. Nutrients like nitrogen (N), calcium (Ca), and magnesium (Mg) could extend the productive life of affected trees, although interactions among these nutrients in HLB-affected citrus trees are still unclear. A 2-year study was established in Florida to determine the response of HLB-affected trees to applications of N, Ca, and Mg. The study was conducted with ‘Valencia’ trees (Citrus sinensis L. Osbeck) on Swingle citrumelo (Citrus paradisi Macf. × Poncirus trifoliata L. Raf.) rootstock on a Candler sand. Applications of N at 168, 224 (recommended rate), and 280 kg⋅ha−1 N were used as the main plots. Split-plots consisted of a grower standard treatment receiving only basal Ca (51 kg⋅ha−1) and Mg (56 kg⋅ha−1); supplemental Ca (total Ca inputs: 96 kg⋅ha−1) only; supplemental Mg (total Mg inputs: 101 kg⋅ha−1) only; and supplemental Ca (total Ca inputs: 73.5 kg⋅ha−1) and Mg (total Mg inputs: 78.5 kg⋅ha−1). The following variables were measured: tree size, fruit yield, and juice quality. Although some differences in tree growth among treatments were statistically significant (e.g., greater canopy volume with Mg fertilization at 168 kg⋅ha−1 N), there was no clear and consistent effect of plant nutrition on these variables. Fruit yield was higher with Ca and Mg relative to the grower standard at the lowest N rate in 2020, and there were no other statistically significant differences among treatments. Juice acidity was significantly higher with Mg fertilization relative to other treatments in 2019. As N rates had no significant effect in this study, unlike secondary macronutrients, N rates could potentially be reduced to 168 kg N⋅ha−1 in HLB-affected citrus without affecting vegetative growth, fruit yield, and juice quality. However, this will require optimizing the supply of secondary macronutrients and all other nutrients to develop a balanced nutritional program. Ultimately, the effects of N, Ca, and Mg obtained in this 2-year study should be confirmed with longer-term studies conducted at multiple sites.

Open access

Claire Adkison, Kelly Richmond, Nico Lingga, Veronique Bikoba, and Elizabeth Mitcham

With increasing walnut production in California, walnuts are stored for longer times. It is increasingly important to optimize storage conditions, wherever possible, to reduce quality degradation. We examined the effects of temperature (5, 15, and 25 °C) and relative humidity (20%, 40%, and 60% in year 1 and 40%, 60%, and 80% in year 2) on the rate of quality degradation of four walnut varieties. The relationship between water activity and moisture content was investigated for each variety. In addition, the effects of harvest timing (early vs. late) and storage as shelled or in-shell product were investigated. Later harvested walnuts had darker kernel color (P < 0.001), and walnuts stored as kernels (shelled) had higher rates of peroxide formation and free fatty acid development than walnuts stored in-shell. Temperature had a significant effect on quality with faster degradation at higher temperatures. There was a significant interaction between temperature and relative humidity effects on quality. The effects of relative humidity were often not significant at storage temperatures of 5 °C but were apparent at 15 °C and at 25 °C. Managing relative humidity during walnut storage is difficult under typical commercial storage conditions; however, when low temperature storage is used, quality is preserved even when relative humidity is not controlled, although storage at 80% relative humidity should be avoided. To reduce the rate of color darkening and rancidity development during commercial storage, operators should emphasize storage at lower temperatures, at least below 15 °C.