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- Author or Editor: Jianjun Chen x
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Hops (Humulus lupulus) is a perennial, herbaceous crop cultivated for its strobiles, or cones, which contain a resinous compound used for flavoring and aroma in food, tea, and beer. The United States is the second largest global producer of hops with greater than 15,000 ha in production. Increased demand for hop products has recently resulted in production of hops in nontraditional production areas (non-Pacific northwest U.S. region). To examine cultivation potential of hops within the southeastern United States, 60 hop rhizomes consisting of four varieties were transplanted into native, deep sand soil (Candler and Tavares-Millhopper soil series) within a protected, open-sided greenhouse and evaluated for growth, strobile yield, and brewing values for a period of 2 years. Plant bine length was recorded weekly for 20 weeks throughout year 1 with mean bine lengths of 609, 498, 229, and 221 cm at harvest for ‘Chinook’, ‘Columbus’, ‘Amalia’ and ‘Neo1’, respectively. Mean harvested strobile dry weight recorded for year 1 was 21.2, 17.9, 9.0, and 8.2 g/plant for ‘Columbus’, ‘Chinook’, ‘Neo1’ and ‘Amalia’, respectively. With the exception of ‘Neo1’, mean strobile mass was lower for all cultivars during year 2 with 16.6, 10.3, 25.8, and 2.6 g/plant for ‘Columbus’, ‘Chinook’, ‘Neo1’ and ‘Amalia’, respectively. Alpha acid concentrations by percentage strobile mass for year 1 were 6.8%, 9.7%, 3.8%, and 4.3% for ‘Columbus’, ‘Chinook’, ‘Amalia’, and ‘Neo1’, respectively. Alpha acids varied year 2 with concentrations of 4.8%, 10.4%, and 5.6% for ‘Columbus’, ‘Chinook’, and ‘Neo1’, respectively. Findings support viability of hop production in the southeastern United States and establish the benchmark for future varietal trialing investigations.
Ploidy levels and genome sizes have significant implications in plant evolution and crop improvement. Species of Lonicera L. have long been cultivated as medicinal, ornamental crops, or both. However, chromosome numbers, karyotypes, and DNA contents have only been documented in a few species, of which some controversies regarding basic chromosome numbers and karyotypes remain. This study analyzed the chromosome numbers and karyomorphology of 11 cultivars across four species and also the DNA content of 10 cultivars representing six species of Lonicera. Among them, the chromosome numbers of nine cultivars are reported for the first time. Results showed that the basic chromosome number of x = 9 was constant, and chromosome numbers of 2n = 18, 27, 36, or 54 were observed, suggesting that polyploidy exists in the genus. Five cultivars are diploid with 2n = 18; one cultivar is triploid, four are tetraploid, and one is hexaploid. The karyotypes of all studied cultivars are 3B or 3A, except Lonicera sempervirens ‘Crimson Cascade’ that is 2B based on the Stebbins’ asymmetry classification of karyotypes. The asymmetry index (A1) values vary from 0.47 to 0.60. The chromosome lengths range from 0.77 to 4.09 μm. Total karyotype lengths differ from 33.55 to 78.71 μm. The 1C-value of 10 cultivars varies 3-fold, ranging from 1.158 to 3.664 pg. Information gathered from this study could be valuable for improving breeding efficiency in the development of new cultivars of Lonicera with enhanced medicinal, ornamental value, or both.
Irrigation runoff water from a containerized landscape plant production bed was blended with rainwater from green house roofs in a constructed collection basin. Water from both the collection basin and an on-site potable well were characterized and used to grow foliage and bedding plants with overhead and ebb-and-flow irrigation systems. Over a 2-year period, a total of 18 foliage and 8 bedding plant cultivars were produced with plant growth and quality quantified. Alkalinity, electrical conductivity, hardness, and concentrations of nutrients of water from both sources were well within desired levels for greenhouse crop production. Turbidity and pH were relatively high from algal growth in the collection basin. However, substrate pH, irrigated by either water source, remained between 6 and 7 throughout the production periods. All plants at the time of finishing were of marketable sizes and salable quality independent of water source. No disease incidences or growth disorders related to water sources were observed. Results suggest that captured irrigation runoff blended with rainwater can be an alternative water source for green house crop production.
Tissue culture plugs of Aglaonema `Cory', `Maria', and `Silver Queen' and Dieffenbachia `Panther', `Snowflake', and `Sport Lynn' were potted singly in 15-cm pots and grown in a shaded greenhouse under a photosynthetic irradiance (PI) of 100 mmol·m–2·s–1. Eight months after potting, 27 plants of each cultivar were placed in nine interior evaluation rooms under three different PI levels (three rooms per level): 4, 8, and 16 mmol·m–2·s–1. In addition, three plants of each cultivar were maintained in the original greenhouse for the duration of the experiment. Number of leaves, plant height and width were monitored monthly. Recently matured leaves were removed at 3-month intervals for 9 months for determination of fresh and dry weight, leaf area, and percentage leaf variegation. Variegated leaf area was assessed using digitized leaf images. Interior PI levels affected growth parameters, but the degree of response was cultivar-dependent. Smallest leaves developed on plants grown under 4 mmol·m–2·s–1 and largest leaves developed under 16 mmol·m–2·s–1. Leaf area of Dieffenbachia `Sport Lynn' showed the greatest response and Aglaonema `Maria' the least response to PI levels. Percentage leaf variegation of Dieffenbachia `Snowflake' was least affected and Dieffenbachia `Sport Lynn' was most affected by PI levels. Fresh leaf weight of unit area decreased as PI levels decreased from 16 to 4 mmol·m–2·s–1, however, the decrease in unit area was most pronounced in cultivars that maintained the highest quality ratings. Based on the results of this study, Aglaonema `Maria' and Dieffenbachia `Snowflake' had the most satisfactory interior performance within their respective genera.
Containerized ornamental plant production represents extremely intensive agricultural production. An average of 200,000 containers may occupy 1 acre of surface area, to which a large amount of chemical fertilizers will be applied. Because of the use of high-drainage soilless potting mixes coupled with excessive fertigation, a great amount of nutrients, particularly nitrogen and phosphorus, are leached, which increases the potential for ground and surface water contamination. Over the past 2 decades, research has been centered on developing fertigation delivery systems such as nutrient film techniques, ebb-and-flow and capillary mat systems, for reducing leaching. Relatively limited research has been conducted on improving potting medium substrates to minimize nutrient leaching. The objectives of this study were to determine the adsorption isotherm of six different zeolites to ammonium, nitrate and phosphorus, identify and incorporate desired zeolites in a peat/bark-based medium for reducing nutrient leaching in ornamental plant production. Results indicated that the zeolites possess great holding capacities for ammonium, nitrate, and phosphorus. Compared to control, ammonium leaching was reduced 70% to 90%, phosphorus 30% to 80% and nitrate 0% to 60% depending on zeolite species and quantity used per pot. Zeolite amended media caused no adverse effects on plant growth. Conversely, biomass increased significantly when compared to that of the control.
Anthurium cultivars are being produced primarily as cut-flower plants. Whether Anthurium can be used as a flowering interiorscape plant is not well documented. Therefore, five finished Anthurium cultivars were evaluated in interior acclimatization rooms under two light intensities provided by cool-white fluorescent lamps for 12 hours daily: 16 mmol·m–2·s–1 (low light) and 48 16 mmol·m–2·s–1 (high light). Temperature of the rooms was maintained at 24 °C with a relative humidity of 60%. Total number of open flowers and number of senesced flowers were recorded weekly over 5 months. In addition, plant canopy height and width and total number of leaves were measured monthly. Number of open flowers per week ranged from 1.4 to 4.7 under low light and 2.4 to 6.3 under high light. The cultivar Red Hot showed the best performance with a weekly average flower count of 4.7 under low light and 6.3 under high light. All cultivars continued to produce new leaves, ranging from one to five per month under low light and two to five leaves under high light. Leaves were dark green and shiny under the interior conditions. Growth index of `Red Hot' increased 31% under low light and 20% under high light. Results from this study demonstrate that Anthurium can continue to grow and produce flowers under interior environmental conditions. Variation among cultivars indicates that genetic potential exists for selecting improved cultivars based on interior performance.
Aglaonema is among the most popular tropical ornamental foliage plants used indoors because of its bright foliar variegation, low light and humidity tolerance, and few pests. Aglaonema, however, has been labeled as one of the most chilling-sensitive foliage plants. The dark, greasy-appearing patches on leaves injured by chilling can result in completely unsalable plants. With recent breeding activity, more and more Aglaonema cultivars have been developed and released. How new cultivars respond to chilling temperatures is, however, mostly unclear. This study was undertaken to evaluate cultivar chilling responses to identify chilling-resistant cultivars. Twenty cultivars were chilled at 1.7, 4.4, 7.2, 10, and 12.7 °C for 24 h using a detached single-leaf method and also whole-plant assay. Results indicate that great genetic variation exists among the cultivars, ranging from no injury at 1.7 °C to severe injury at 12.7 °C. A popular cultivar, Silver Queen, is the most sensitive, while the cultivar Stars is the most resistant. There was also a chilling response difference based on leaf maturity. Young leaves showed less injury than did either mature or old leaves. In addition, there was a significant correlation between the single-leaf and whole-plant assay for chilling resistance in Aglaonema'; the single leaf assay could be particularly useful for a quick test.
Potted anthurium is becoming an important indoor flowering foliage plant because of its unique attractive appearance and continuous growth and flowering under interior conditions. However, an interior environment, with controlled optimal temperatures and relative humidity and living plants, is an ideal niche for pest development. Pests such as thrips and two-spotted spider mite on Anthurium have been great challenges to the interiorscape industry because many pesticides have been rigorously restricted for interior use. Thus, exploiting the genetic potential of cultivar resistance may be the best approach for the control of these pests. In this study, eight of the most popular Anthurium cultivars were evaluated for their resistance to a natural infestation of thrips (Hercinothrips femoralis) and two-spotted spider mite (Tetranychus urticae) under three light levels: 4, 8, and 16 μmol·m-2·s-1, temperatures of 23.8 to 26.7 °C and a relative humidity of 60%. Results indicated that significant resistant differences exist among cultivars. The cultivars most resistant to thrips were not the most resistant to mite and vice versa. Cultivars that exhibited moderate resistance to thrips were also moderately resistant to mite. Low light intensity appeared to be a factor influencing thrips infestation since control plants that grew under a light intensity of 200 μmol·m-2·s-1 had no observed thrips damage. On the other hand, two-spotted spider mite infestation was not influenced by light intensity.
This study established a new method for regenerating Anthurium andraeanum Lind. and evaluated effects of different wavelengths from light-emitting diodes (LEDs) on rooting and growth of adventitious shoots. Callus occurred in leaf explants of A. andraeanum ‘Alabama’ and ‘Sierra’ cultured on a modified Murashige and Skoog (MS) basal medium supplemented with four concentrations of N-phenyl-N′-1,2,3-thiadiazol-5-ylurea (TDZ). Adventitious shoots were induced from callus pieces (≈1 cm3) cultured on the modified MS medium containing 6-benzyladenine (BA) with kinetin (KN), BA, and/or KN with 3-indolebutyric acid (IBA) or α-naphthalene acetic acid (NAA). Results showed that 1.82 μM TDZ induced 83.3% and 77.8% of leaf explants of ‘Alabama’ and ‘Sierra’ to produce callus and 24.9 and 24.7 adventitious shoots were produced per callus piece of ‘Alabama’ and ‘Sierra’ cultured on the modified MS medium containing 0.89 μM BA, 2.32 μM KN, and 0.98 μM IBA, respectively. Adventitious shoots were cut and rooted in the modified MS medium containing 0.98 μM IBA and grown under the same light level but with different light qualities. All adventitious shoots rooted; root numbers, root lengths, root fresh and dry weights, and leaf area of plantlets grown under red plus blue light were comparable to those grown under conventional fluorescent white light. Shoot height was the greatest in monochromic blue light followed by red light. Shoot fresh and dry weights of plantlets grown under red plus blue light, however, were significantly greater than those grown under the other light qualities. Plantlets grown under red plus blue light had 22.7% greater total dry weight and more balanced root-to-shoot ratio than those grown under fluorescent white light. These results suggested the use of complex of red plus blue LED could be an option for improving growth of A. andraeanum plantlets in vitro.