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Jianjun Chen, Dennis B. McConnell, Richard J. Henny, Kelly Everitt and Russell D. Caldwell

Fire flash (Chlorophytum amaniense), a member of Liliaceae, is attracting considerable attention in the foliage plant industry as a new addition for interior plantscaping. Coral-colored petioles and midribs contrasting with dark green leaves make it a sought after specimen. Originally collected from rainforests of eastern Africa in 1902, it has remained largely obscure for a century. Recently, studies on fire flash's propagation, production, and interiorscape performance have been completed. This report presents relevant botanical information and the results of our 4-year evaluation of this plant. Fire flash can be propagated through seed, division, or tissue culture and produced as a potted foliage plant under light levels from 114 to 228 μmol·m–2·s–1 and temperatures from 18 to 32 °C. Finished plants after being placed in building interiors are able to maintain their aesthetic appearances under a light level as low as 8 μmol·m–2·s–1 for 8 months or longer.

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Jianjun Chen, Dennis B. McConnell, Svoboda V. Pennisi, Cynthia A. Robinson and Russell D. Caldwell

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.

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Jianjun Chen, Yingfeng Huang, Zhen Yang, Russell D. Caldwell and Cynthia A. Robinson

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.

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Jianjun Chen, R.J. Henny, T. Mellich, R.D. Caldwell and C.A. Robinson

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.

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Jianjun Chen, R.W. Henley, R.J. Henny, C.A. Robinson and R.D. Caldwell

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.

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Jianjun Chen, Richard J. Henny, Pachanoor S. Devanand and Chih-Cheng T. Chao

Peace lily (Spathiphyllum Schott) is one of the most popular tropical ornamental foliage plants and is used worldwide for interiorscaping. However, little information is available on the genetic relationships of cultivars. Using amplified fragment length polymorphism (AFLP) markers with near-infrared fluorescence-labeled primers, this study analyzed genetic relatedness of 63 commercial cultivars and breeding lines. Forty-eight EcoRI + 2/MseI + 3 primer set combinations were initially screened, from which six primer sets were selected and used in this investigation. All cultivars were clearly differentiated by their AFLP fingerprints, and the relationships were analyzed using the unweighted pair-group method of arithmetic average cluster analysis (UPGMA). The 63 cultivars were divided into four clusters. All commercial cultivars or breeding lines resulted from crosses of some of the cultivars, a total of 45, were positioned in cluster I with Jaccard's similarity coefficients between 0.61 and 0.88. There was only one cultivar in cluster II. Cluster III contained 16 cultivars; they are either species or breeding lines generated from interspecific hybridization. Cluster IV had one unknown species. This study provides genetic evidence as to why cultivars from cluster I and III are not readily crossable because the Jaccard's similarity coefficient between the two clusters was only 0.35. Results also indicate that commercial cultivars are genetically close. Strategies for increasing genetic diversity of cultivated peace lily should be sought for future breeding efforts.

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Jinggui Fang, Jianjun Chen, Richard J. Henny and Chih-Cheng T. Chao

Ornamental Ficus L. is a group of lactiferous trees, shrubs, and woody root-climbing vines that are cultivated either as landscape plants in the tropics and subtropics or as foliage plants used worldwide for interiorscaping. With the recent rapid expansion of the ornamental plant industry, more new Ficus species and cultivars have been introduced. However, no study has thus far addressed the genetic relationships of cultivated ornamental Ficus. Using amplified fragment length polymorphism (AFLP) markers with near-infrared fluorescence-labeled primers, this study analyzed the genetic relatedness of 56 commercial cultivars across 12 species. Forty-eight EcoRI + 2/MseI + 3 primer set combinations were initially screened, from which six primer sets were selected and used in this investigation. Most cultivars were differentiated by their AFLP fingerprints, and their relationships were determined using the unweighted pair-group method of arithmetic average cluster analysis. The 56 cultivars were divided into 12 clusters that correspond to 12 species, indicating that no interspecific hybrids of ornamental Ficus are in commercial production. The 12 species are genetically diverse, with Jaccard's similarity coefficients ranging from 0.21 to 0.43. However, cultivars within three species—Ficus benjamina L., Ficus elastica Roxb. Ex Hornem., and Ficus pumila L.—are genetically close. Twenty-seven of the 29 cultivars of F. benjamina and five cultivars of F. pumila had Jaccard's similarity coefficients of 0.98 or higher respectively. Nine cultivars of F. elastica shared Jaccard's coefficients higher than 0.96. These results indicate potential genetic vulnerability of these cultivars within the three species. Because there are increasing reports of invasive pests in the ornamental plant industry, strategies for conserving genetic resources and broadening genetic diversity of cultivated Ficus are discussed.

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Jianjun Chen, Richard J. Henny, David J. Norman, Pachanoor S. Devanand and Chih-Cheng T. Chao

Dieffenbachia Schott is an important ornamental foliage plant genus. A total of 30 species has been recognized, but most cultivars come from or are related to a single species, D. maculata (Lodd.) G. Don. At least 11 of the cultivars are sports or somaclonal variants. As a result, the potential lack of genetic diversity in cultivated Dieffenbachia has become a concern. However, no research has been conducted to determine the genetic relatedness of the cultivars. This study analyzed the genetic similarity of 42 Dieffenbachia cultivars using amplified fragment length polymorphism (AFLP) markers. Six primer sets, selected from an initial screening of 48, generated a total of 453 scorable AFLP fragments of which 323 (71%) are polymorphic. All cultivars were clearly differentiated by their AFLP fingerprints. A dendrogram was constructed using the unweighted pair-group method of arithmetic averages, and principal coordinated analysis was carried out to show multiple dimensions of the distribution of the cultivars. The 42 cultivars were divided into three clusters; clusters I and II comprise 18 and 23 cultivars, respectively. Jaccard's similarity coefficients for cultivars in the clusters I and II varied from 0.44 to 0.95 and 0.41 to 0.87, respectively. These results indicate that broadening the genetic variability in the Dieffenbachia gene pool is needed, but the genetic similarity of many cultivars is not as close as previously thought. Additionally, Jaccard's similarity coefficients between most sports or somaclonal variants and their parents were 0.73 or lower, suggesting that accumulation of somatic mutations through tissue culture may play a role in the increased variation between some sports or variants and their parents.

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Jin Cui, Juanxu Liu, Min Deng, Jianjun Chen and Richard J. Henny

Syngonium podophyllum ‘White Butterfly’, one of the most popular ornamental foliage plants, is propagated almost exclusively through in vitro shoot culture. Ex vitro rooting, however, has been associated with severe Myrothecium leaf spot (Myrothecium roridum Tode ex Fr.). The objective of this study was to establish a method for regenerating well-rooted plantlets before ex vitro transplanting. Leaf and petiole explants were cultured on a Murashige and Skoog (MS) basal medium supplemented with N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU), N-phenyl-N′-1,2,3-thiadiazol-5-ylurea (TDZ), 6-benzyladenine (BA), or N-isopentenylaminopurine (2iP) with α-naphthalene acetic acid (NAA) and 2,4-dichlorophenoxyacetic acid (2,4-D), respectively. Calli formed from leaf explants cultured on the basal medium supplemented with CPPU or TDZ with 2,4-D or with NAA as well as from petiole explants cultured on the medium supplemented with BA, CPPU, or TDZ with 2,4-D or NAA. The calli, however, failed to differentiate, and shoot organogenesis did not occur. Culture of nodal explants on the MS basal medium supplemented with 9.84 μm 2iP, 8.88 μm BA, 8.07 μm CPPU, or 9.08 μm TDZ with 2.26 μm 2,4-D resulted in the formation of protocorm-like bodies, adventitious shoots, and subsequently well-rooted plantlets. MS basal medium supplemented with 19.68 μm 2iP and 1.07 μm NAA resulted in the highest percentage (92.9%) of nodal explants producing protocorm-like bodies and an average of 16.9 well-rooted plantlets per nodal explant. Adventitious shoots were able to root in the initial induction medium, but better root development occurred after shoots with protocorm-like bodies were transferred onto MS basal medium supplemented with 9.84 μm 2iP and 2.69 μm NAA. Regenerated plantlets were stable and grew vigorously with 100% survival rates after ex vitro transplanting to a container substrate in a shaded greenhouse.

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Yuncong Li, Edward Hanlon, George O'Connor, Jianjun Chen and Maria Silveira

Compost is the product resulting from the controlled biological decomposition of organic material that has been sanitized through the generation of heat and processed to further reduce pathogens as defined by the U.S. Environmental Protection Agency and stabilized to the point that the compost is beneficial to plant growth. Organic materials used for composting in Florida are mainly yard wastes (trash) and food wastes. More than 5.7 million tons of composts could be produced from yard trash and food waste in the state. Animal manure and biosolids (treated sludge) can also be composted, but are not discussed in this article. “Other wastes” as discussed herein [food processing wastes, coal ash, wood ash, drinking water treatment residuals (WTRs), and phosphogypsum] are by-products of leading Florida industries and are available in large quantities for reuse. About 5 million tons of food processing waste [citrus (Citrus spp.) and vegetables alone], 1.85 million tons of coal ash (from 28 coal-burning power plants), 0.05 million tons of wood ash, 1000 million tons of phosphogypsum (from the state's phosphate fertilizer industry), and significant, but unknown, amounts of WTRs are available. Due to the growing interest in sustainable agriculture practices, this article is intended to discuss the current regulations and guidelines for composting and the use of composts and other wastes in Florida, the characteristics, benefits, and concerns of Florida compost and other wastes, and current research and needs of research and extension for incorporating compost and other waste materials in Florida's sustainable agriculture. Our literature search was largely limited to studies conducted in Florida.