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An instructional system involving tropical hibiscus (Hibiscus rosa-sinensis) was developed for teaching hands-on grafting skills as part of a traditional comprehensive course in plant propagation and also as part of an online grafting course. The advantages of using tropical hibiscus include the following: the absence of phenological constraints associated with seasonal changes in temperate woody species; the comparative ease of grafting hibiscus, assuring positive reinforcement of the student's learning experience; and the ease of propagating and growing hibiscus in the greenhouse for use at any time of year. The three methods included in these laboratory exercises are top wedge grafting—selected for its ease and high rate of success—T-budding, and chip budding. In addition to development of hands-on skills, the exercises are designed to teach students three of the most important requirements for successful grafting of any species, regardless of method. These requirements include cambial alignment, application of pressure between stock and scion, and avoidance of desiccation. An online rating tutorial and lab report form was developed for students to self-evaluate their grafted plants.

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Tropical hibiscus ( Hibiscus rosa-sinensis L.), also commonly known as the shoe flower or chinese hibiscus, is a widely planted tropical flowering shrub throughout the world. This cultivated species is generally a highly heterozygous polyploid of

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The objective of this study was to investigate the effects of multiple nutrient salt formulations and different plant growth regulator concentrations on initiation and proliferation of axillary shoot culture of tropical hibiscus (Hibiscus rosa-sinensis L.). Combinations of five thidiazuron (TDZ) concentrations (0, 10-6, 10-7, 10-8, or 10-9 M) in conjunction with two 6-benzylaminopurine (BA) concentrations (0, 10-5 M) and two indole-3-butryic acid (IBA) concentrations (0, 10-5 M) were compared to determine which plant growth regulator combination(s) would stimulate the proliferation of the most viable axillary shoots. Also, five nutrient salt formulations (MS, 1/2 MS; Macro MS, WPM, LP, or DKW) ranging from high to low salt formulations were studied to determine a suitable nutrient medium formulation for axillary shoot proliferation. Nodal explants that were 2 cm in length were used to initiate cultures and were maintained on the various medium treatments plus 30 g·L-1 sucrose and 7 g·L-1 agar at a pH of 5.8. Explants were incubated about 30 cm beneath cool-white fluorescent lamps that provide a photon flux of about 40 μM·m-2·s-1 for a 16-hour photoperiod at 25 ± 3 °C. Nodal explants were transferred every 3 weeks for a total culture period of 12 weeks. At each transfer date data were collected on node number, axillary shoot number and length. Initial results indicate that high nutrient salt formulations coupled with low TDZ concentrations performed better at axillary shoot initiation. Poor shoot elongation was observed and further research needs to be performed to address this issue.

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A commercially available microbial inoculant (Plant Growth Activator Plus) that contains 50 microorganisms, primarily bacteria, was evaluated in a soilless container substrate to determine its effects on root bacterial populations and growth response of container-grown plants at three fertilizer rates. The tropical ornamental plants included hibiscus (Hibiscus rosa-sinensis `Double Red'), spathiphyllum (Spathiphyllum `Green Velvet') and areca palm (Dypsis lutescens). The bacterial groups enumerated were fluorescent pseudomonads, actinomycetes, heat-tolerant bacteria, and total aerobic bacteria. Analysis of the inoculant before its use determined that fluorescent pseudomonads claimed to be in the inoculant were not viable. The plant variables measured were plant color rating, shoot dry weight and root dry weight. Only hibiscus shoot dry weight and color rating increased in response to the addition of the inoculant to the substrate. Hibiscus roots also had a significant increase in the populations of fluores-cent pseudomonads and heat-tolerant bacteria. From a commercial production point of view, increasing fertilizer rates in the substrate provided a stronger response in hibiscus than did addition of the microbial inoculant. Furthermore, use of the inoculant in this substrate did not compensate for reduced fertilizer inputs.

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It is generally accepted that modern agriculture in tropical areas was first practised in the early days of colonialism when the main aim was production of items required in large quantities by the metropolitan nations. For this reason there developed plantations where crops like coffee, cotton, sugarcane and tobacco were grown on an extensive scale for export after simple preparation of the produce to enable it to withstand slow travel by sea; interest in horticultural crops which require intensive methods of production and rapid travel was to come much later. However, the existence of tropical fruits, vegetables and ornamental plants in abundance and great variety could not be ignored for long and, in time, the traditional approach to horticulture in temperate regions was adopted in the tropics also: plants were grown to produce crops for immediate use and the local market. It is remarkable that sometimes the names of horticultural crops of more temperate areas were attached quite inappropriately to a number of them, like avocado pear (Persea americana) and rose-of-sharon (Hibiscus mutabilis). Increasing familiarity bred appreciation of tropical horticultural produce and led to a growing demand most notably, for fruits but also for vegetables, flowers and ornamental foliage. The inevitable outcome has been the movement of larger quantities from the areas of production to the expanding areas of consumption – a prerequisite of a satisfactory export trade.

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). Winter-hardy hibiscuses, especially H. moscheutos and its hybrids, have attractive, tropical-looking flowers with a size of 5 to 30 cm in diameter. Winter-hardy hibiscus species are long-day plants ( Warner and Erwin, 2001 ). All species of winter

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, especially H. moscheutos and its hybrids, have attractive, tropical-looking flowers reaching up to 30 cm in diameter. Winter-hardy hibiscus species are long-day plants ( Warner and Erwin, 2001 ) that abundantly produce flowers from midsummer through late

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Viterra hydrogel at rates of 0, 1.75, or 2.50 kg·m−3 was tested for the production of three tropical ornamental plant species in two or all of the three media. These were a commercial peat-lite medium (SUN), a medium consisting of equal volumes of peatmoss, bark, and sand (PBS), and a mix containing equal volumes of peatmoss and bark (PB). Codiaeum was grown in SUN and PBS, Dieffenbachia was produced in all three media, and Hibiscus was planted in SUN and PB. Codiaeum variegatum (L.) Blume ‘Norma’ and Dieffenbachia ‘Camille’ grew more and required a longer time to reach initial wilting when grown in SUN than PBS. Hibiscus rosa-sinensis L. ‘Brilliant Red’ had similar growth in SUN and PB. In general, hydrogel had no beneficial effect on plant growth in a greenhouse. Hydrogel extended the time required to reach initial wilting of C. variegatum by 3 days (from 24 to 27 days), but had no effect on Dieffenbachia. Leachate from PBS had higher pH and lower electrical conductance (EC) than that from SUN. Hydrogel had no effect on leachate pH, but decreased EC of the leachate for C. variegatum used at the 2.5 kg·m−3 rate and for H. rosa-sinensis at both rates.

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The effects of four propagation moisture management systems on the water relations and rooting of cuttings of three tropical woody crops were investigated at a relatively cool, but high irradiance site. Leafy semihardwood or leafless hardwood cuttings of Bougainvillea × Buttiana Holtt. & Standl. (bougainvillea), and leafy semihardwood cuttings of Hibiscus rosa-sinensis L. (hibiscus), and Dovyalis caffra (Hook. f. et Harv.) Warb. (kei apple) were propagated in shade under contact tent polyethylene enclosures or in the open with or without intermittent mist. Xylem water potential and leaf and air temperatures and relative humidity were monitored during the rooting period. Hardwood cuttings rooted better than softwood cuttings of bougainvillea. The best rooting of softwood cuttings of all three species was consistently associated with contact polyethylene, whereas open-propagated, nonmisted cuttings rooted poorly or not at all. The poor rooting of open-propagated nonmisted cuttings was associated with the most negative midday ψ and the greatest water vapor density deficit of air surrounding the cuttings (VDDA), but ψ and VDDA were otherwise not consistently associated with success of rooting in other treatments. Midday ψ of cuttings under contact polyethylene was either less negative or not different from that of other treatments despite the fact they exhibited the greatest daytime leaf and leaf to air temperature differences. Because ambient night temperatures were suboptimal for rooting, the warm air trapped beneath the polyethylene enclosures at night may have contributed to improved rooting in these treatments.

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Results of a series of experiments showed that the ground, noncomposted woody stem core of kenaf (Hibiscus cannabinus L.) can be used successfully as a container medium amendment for producing potted tropical foliage and woody nursery crops. The growth of Brassaia actinophylla Endl., Hibiscus rosa-sinensis L. `Jane Cowl', and Pittosporum tobira (Thunb.) Ait. `Wheeler's Dwarf' in 70% or 80% kenaf (by volume, the balance being peatmoss or perlite or vermiculite and other nutrients) was similar to or greater than growth in two popular commercial mixes. Undesirable shrinkage of certain kenaf-amended media during plant production was reduced greatly by mixing it with at least 30% peatmoss or by using a coarser kenaf grind. As the portion of peatmoss increased from 0% to 30%, noncapillary porosity and water-holding capacity per container increased. A medium consisting of 50% kenaf, 40% peatmoss, and 10% vermiculite held as much water as a commercial medium. However, plants in most kenaf-amended media required more-frequent irrigation than those in the commercial media.

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