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We compared the performance of Brussels sprout (Brassica oleracea var. gemmifera) cultivars in New Hampshire and evaluated the effects of topping (apical meristem removal) on marketable yields. A total of 23 cultivars were evaluated in the study, with 8 to 16 cultivars evaluated in any given year. We identified several cultivars that produced moderate to high yields of well-spaced, uniform sprouts that had few Alternaria blight (Alternaria sp.) symptoms, and identified many others, including all red cultivars evaluated, that produced very low yields consistently. In 2013, 2014, and 2015, we used a replicated split-plot experimental design with cultivar as the main plot and topping treatment as the subplot, to evaluate the effects of topping plants. Early and midseason cultivars showed increased yields in response to topping, unless topping was performed too early. Cultivars with sprouts that did not reach marketable size within our growing season generally produced low yields, and topping had no effect on yields. To explore the effects of topping at different dates, we evaluated three cultivars on seven different topping dates plus an untopped control in 2015 and 2017. In addition to reducing stalk height by limiting late-season growth, topping affected marketable yields by affecting the number of sprouts that were either undersized or oversized. The ideal topping date window for minimizing defects and maximizing yields varied slightly for each cultivar, ranging from early to late September.
‘Crimson Cabernet’ grape (Vitis vinifera) seeds showed physiological dormancy and germinated at ∼60% after 60 days of chilling stratification. Fresh seeds harvested after physiological maturity and sown without drying failed to germinate after 30 days when sown on agar. In agar-sown fresh seeds cut at the distal seed end or intact seeds treated with gibberellic acid (GA), the seeds germinated at ∼20% after 30 days. The highest germination percentages after 30 days were 63% to 83% in fresh, agar-sown seeds that were cut and treated with GA at 5000 mg⋅L–1 regardless of stratification time. Similar results were seen in seeds allowed to dry before sowing. Seeds cut and treated with GA at 5000 mg⋅L–1 germinated at 79% after 30 days. However, dry seeds sown on germination paper showed lower germination after cutting and GA treatment compared with agar-sown seeds. The highest germination percentages after 30 days in dry, cut seeds on germination paper treated with GA at 2000 and 5000 mg⋅L–1 were 33% and 55%, respectively, compared with agar-sown seeds, which germinated at 76% and 79%, with the same treatments. Results from this study provide a system that reduces the need for chilling stratification for grape seed germination by using partial seedcoat removal and GA treatment.
Increasing labor and input costs have driven wine grape (Vitis vinifera) growers’ attention to mechanized equipment to assist in vineyard operations. This study evaluates the financial feasibility of investing in vineyard mechanization, in addition to the released intelligent sprayer in hypothetical wine grape vineyards of varying sizes. Our comparative analysis illustrates how mechanization of vineyard practices affects costs and financial metrics. We conducted a cost–benefit analysis for seven investment scenarios and examined the economic performance of four metrics. Our findings suggest that investing in a mechanized trimmer is most effective for growers exposed to labor shortages and high wages. A retrofitted intelligent sprayer is superior for reducing input use and associated costs.
Micropropagation of hemp (Cannabis sativa) is constrained by problems with hyperhydricity and culture decline of microshoots. These problems can be reduced by increasing agar and nutrients in the media during micropropagation stages 1 and 2, respectfully. Performance of microshoots of ‘Abacus’ and ‘Wife’ hemp cultured in Driver and Kuniyuki Walnut medium (DKW) for 15 weeks (6 weeks of stage 1 + 9 weeks of stage 2), with subculturing every 3 weeks during both stages 1 and 2, or in Murashige and Skoog with vitamins medium (MS) for 6 weeks (stage 1) followed by Lubell-Brand Cannabis medium (LBC) for 9 weeks (stage 2), with subculturing every 3 weeks during both stages 1 and 2, was evaluated. In a separate study, microshoot performance of ‘Abacus’ and ‘Wife’ in MS for 3 weeks (stage 1) followed by LBC for 6 weeks (stage 2), with subculturing every 3 weeks, using boxes (Magenta GA-7) with lids featuring a vent with a diameter of 10 mm and a pore size of 0.2 µM or using microboxes (Sac O2 O95/114 + OD95) with lids featuring a filter (Sac O2 #10) were evaluated. Shoot multiplication rate (SMR) and explant height were greater for ‘Abacus’ in LBC than DKW. For ‘Wife’, SMR at 9 weeks was greater in LBC, as LBC provided more nutrients and water than cultures had received in MS initially during stage 1. Culture medium did not influence ex vitro rooting success, which was 75% for ‘Abacus’ and ≥ 90% for ‘Wife’. Microboxes resulted in greater hyperhydricity of shoots and a lower ex vitro rooting percentage than boxes. For cultivars that are highly prone to developing hyperhydricity, like ‘Abacus’, the microboxes were not adequate to control this condition.
During the past few years, Americans have experienced a wide variety of stressors, including political tensions, racial/civil unrest, and the coronavirus disease 2019 (COVID-19) pandemic. All of these have led to uncertainty within society. Chronic feelings of helplessness can lead to depression or feelings of hopelessness in those who perceive their situation as unchanging. The purpose of this study was to evaluate the impacts of gardening and outdoor activities during the COVID-19 pandemic on perceptions of hope, hopelessness, and levels of depression, stress, and anxiety. Participants of this study were recruited through online social media platforms such as Facebook and Instagram; 458 participants completed the 21-item Depression Anxiety and Stress Scale inventory as well as the Hope Scale. Our data indicated that individuals who self-reported themselves as gardeners had significantly more positive scores related to levels of stress, anxiety, and depression and a sense of hope. Furthermore, gardeners had lower levels of self-reported depression, anxiety, and stress when compared with those who did not identify themselves as gardeners. The gardeners also had a more positive outlook regarding hope for the future. Additionally, a significant positive correlation was found between the number of hours spent participating in gardening and a sense of hope, and a negative correlation was found between the number of hours gardening and stress levels. Similarly, there was a significant negative correlation between the number of hours spent participating in any outdoor activity and self-reported levels of stress, anxiety, or depression; however, there was a positive correlation between the number of hours spent participating in any outdoor activity and a sense of hope. Our data suggested that more hours spent outside gardening or participating in recreational activities led to less perceived stress, anxiety, and depression and greater levels of hope for the future.
Copper (Cu) is typically adequate at 0.5 μM (0.03 ppm) in hydroponics and at 2 μM (0.125 ppm) in soilless media, but elevated levels can be used to inhibit pathogenic fungal growth. We studied the effect of elevated Cu on the growth of lettuce and tomato in peat-based media and deep-flow hydroponics. Lettuce growth in hydroponics was not hindered until a concentration greater than 4 μM (0.25 ppm) Cu was used, which is eight times greater than the adequate level. Tomato was more tolerant of elevated Cu, with no growth suppression up to 8 μM (0.5 ppm) in hydroponics. Organic matter tightly binds Cu, and bioavailability is thus determined by organic components in soilless media. We confirmed an adsorption capacity of 19 mg Cu per g of peat, which explains why there was no inhibition of lettuce or tomato growth up to 1000 μM (64 ppm) Cu in peat-based media. When chelated with ethylenediaminetetraacetic acid, Cu binding to organic matter was reduced and growth was decreased in lettuce but not tomato. Both species tolerated a 100-fold greater concentration of Cu in peat-based media than in deep-flow hydroponics. Elevated Cu in solution increased concentrations 20 times greater in root tissue than in leaves. These solution and tissue concentrations are greater than identified toxicity thresholds of pathogenic fungal and fungal-like organisms, and could thus be used to suppress root-borne fungal and fungal-like diseases.
Creeping bentgrass (Agrostis stolonifera L.) is a turfgrass species that is widely used on golf courses throughout the United States. In field settings, plants are often subjected to more than one stress at a time, and studying stresses independently is likely insufficient. Stresses, such as heat stress and salt stress, can affect plant hormone levels and, in turn, plant hormone levels can affect how well the plant tolerates stress. The objectives of the experiments were to determine if the levels of heat stress and salt stress used would be detrimental to creeping bentgrass health, and if applying plant growth regulators could improve plant health during stress. During the first experiment, creeping bentgrass was transplanted to hydroponics systems in two different growth chambers. One chamber was set to have day and night temperatures of 35 °C and 30 °C (heat stress), respectively, and the other had day and night temperatures of 25 °C and 20 °C, respectively. Within each chamber, one block received a 50 mM NaCl treatment (salt stress) and the other did not (control). The stress treatments were applied for 14 days. Results of the first experiment indicated that the treatments were sufficient to negatively affect creeping bentgrass growth and health as indicated by fresh shoot and root weights, tillering, electrolyte leakage, and total chlorophyll content (TCC). There were significant interactions of temperature × salt level detected for shoot and root weights and electrolyte leakage. Plants that were exposed to both heat stress and salt stress were more negatively affected than plants exposed to either heat stress or salt stress alone for all metrics except for tillering. The presence of salt reduced tillering regardless of the temperature regimen. During the second experiment, plants were treated the same, but the plant growth regulator (PGR) treatments were also applied. The PGR treatments consisted of two different gibberellic acid (GA) synthesis inhibitor products, 2,4-dichlorophenoxyacetic acid, two different rates of aminoethoxyvinylglycine (AVG), an ethylene synthesis suppressor, and plants that were not treated with the PGR. In addition to the measurements of plant health and growth, dry shoot and root weights were measured. For the TCC, there was a two-way interaction between temperature × PGR treatment. For electrolyte leakage, there was a three-way interaction between temperature × salt level × PGR treatment. Combined heat stress and salt stress negatively affected all plants regardless of PGR treatment, but there were differences between PGR treatments. Plants treated with AVG exhibited improved health and growth compared with the other PGR treatments. These plants had the highest shoot and root masses. Plants treated with GA synthesis inhibitors had the lowest shoot and root masses as well as the lowest TCC when subjected to stress.
This study examined the interaction between constant liquid fertilization (CLF) concentrations and plant growth regulator (PGR) application concentrations on petunia (Petunia ×hybrida) growth and flowering in the production and post-production environments. Paclobutrazol application is a common practice in bedding plant production to achieve a compact plant that increases greenhouse space-use efficiency, shipping density, and tolerance to physical handling stresses in the post-production environment. The objective of this research was to determine the best strategy for balancing CLF and PGR application concentration in the greenhouse environment so that growth and flowering can be maximized in the post-production environment. A two-factorial combination of four CLF concentrations [50, 100, 150, or 200 ppm nitrogen (N)] and four paclobutrazol drench concentrations (0, 5, 10, or 20 ppm) were provided to plants during the production phase, and plant growth and flowering were recorded in the production and post-production environments. From a sustainability perspective, the ideal PGR concentration was 5 ppm paclobutrazol, since this concentration resulted in the best combination of production and post-production characteristics and performance. At this PGR concentration, all plant growth and flowering measures increased as CLF increased from 50 to 200 ppm N; however, all CLF concentrations also produced commercially acceptable plants. Therefore, the ideal CLF concentration depends on the size of plant desired; that is, CLF concentrations as low as 50 to 100 ppm N can be provided depending on the market size requirements of the plants being grown. Based on our results, a combination of 50 ppm N CLF with 0 ppm paclobutrazol or 100 ppm N CLF with 5 ppm paclobutrazol both demonstrated adequate growth control during both production and post-production phases.
Paeonia lactiflora is a high-value crop with a temperature-dependent growth response that requires worldwide production to satisfy year-round demand. The objective of this study was to evaluate production and timing of ‘Coral Charm’ peony as a cool-season crop in the US Intermountain West. High-tunnel and field production were trialed in North Logan, UT, USA (lat. 41.77°N, long. 111.81°W; elevation, 1382 m) with the addition of low tunnels and soil heating methods to advance growth in 2019–21. Soil and air temperatures, as well as the date and quality of harvested stems, were measured. High tunnels yielded 15.7 ± 3.3 to 19.4 ± 2.1 stems/m2 [± standard error (SE)] and the high tunnel alone advanced initial harvest 21 to 34 days earlier than natural field conditions. The field yielded 16.1 ± 1.9 to 20.8 ± 1.6 stems/m2 and staggered production, resulting in a harvest duration up to 38 days across the high tunnel and field. The use of a low tunnel with soil heating advanced the initial harvest date compared with natural (i.e., unmanipulated) high-tunnel and field conditions by 3 and 7 days in 2019, 6 days in 2020, and 16 and 6 days in 2021 in the high tunnel and field, respectively. However, the quality decreased significantly under low tunnels with soil heating within high tunnels, compared with unheated plants, as a result of superoptimal temperatures and humidity that damaged buds and led to an increase in disease and insect pressure. Overall, increasing soil temperature advanced early stages of production when the meristem was below or near the soil surface, whereas increased air temperatures accelerated stem elongation and advanced time to flowering.