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Fruit and ornamental breeders were surveyed about their use of molecular markers in either their breeding programs or in their related research programs. Responses were obtained from over 100 fruit and ornamental breeding programs from throughout the world. Of these, less than 50% used molecular markers in their programs. The two most common uses of these markers were for studies in plant identification and diversity. These were followed by the use of markers in developing molecular maps, in discovering molecular tags and/or trying to identify the genes for specific plant traits, for marker assisted selection, and finally, for the elucidation of plant taxonomy. In conclusion, although there is much research in this area, few programs are actually using markers in the context of an applied breeding program. The major reason for this situation is the lack of available markers and the cost of using these markers to screen large numbers of progeny. Those that use markers in their breeding tend to use them to verify the genotype of the parents or confirm the genotype of selected seedlings rather than screen unselected seedlings.
Elemental deficiencies of N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn, and B were induced in `Osaka White' ornamental cabbage (Brassica oleracea var. acephala L.) plants. Seedlings were planted in 4.7-L plastic containers and fertilized with a complete modified Hoagland's solution or this solution minus the element that was to be investigated. Plants were harvested for tissue analysis as well as dry weight when initial foliar symptoms were expressed and later under advanced deficiency symptoms. Root architecture was also recorded for the plants treated with the solutions. The containers were replicated three times for each of the two harvests and were randomized in a complete-block design. Deficiency symptoms for all treatments were observed within five weeks. The most dramatic expression of foliar symptoms occurred with N (a purplish tinge on underside of lower foliage leading to necrotic margins on the mature leaves), P (elongated internodes and a purplish tinge on underside of mature leaves), K (compact internodes with chlorotic lower foliage leading to necrotic patches on the leaf margins and blade), Fe (bright yellow upper foliage leading to a bleach white appearance), Ca (complete meristem necrosis with lower foliage becoming chlorotic then necrotic), and B (deformed young leaves and fully expanded leaves becoming thick, leathery, and brittle). The dry weight of plants treated with solutions not containing N, P, Ca, Fe, or B was significantly lower when compared to the control. Foliar tissue concentration data will assist plant tissue analysis laboratories in establishing foliar symptom standards for grower samples.
Taking Beihua shan and Wuling shan mountain as examples, the author investigated the Wild Ornamental Plants (WOP) resources in mountain area of northern China in detail with ecological systematic sampling method. The meteorological data of no meteorological observed plots was reckoned theoretically using statistics. And then the main factors that influence the WOP distribution were sifted out by the progressive regression analysis. At last the optimized chains of adaptability with which the WOP will be introduced from mountain to urban area and of most suitable place on which certain plants will be introduced were defined. In order to enrich the capital Beijing's afforestation materiels, this paper offers a reliable basis in terms of theory.
Although genetically modified (GM) ornamental cut flowers are now available commercially, we have no knowledge of consumer perception about GM ornamental plants for landscape use and must make inferences from models drawn for GM foods. If we misjudge the customer, and consumers object to GM ornamental plant products for moral reasons, governmental or scientific mistrust, or limited understanding about GM technology, the market for GM ornamental plant commodities will fail. A survey of Master Gardener volunteers was conducted in 2004 to address this gap. Although Master Gardener perceptions likely differ from those of general U.S. consumers, responses are expected provide insight about beliefs applicable to the gardening public. Results from 607 Tennessee respondents revealed that concerns about GM ornamental plants parallel those expressed in the United States about GM foods. On average, Master Gardeners anticipate slight benefits to both the environment and human health should GM ornamental plants be introduced into the landscape. Male respondents chose perennials to provide the most environmental benefits, whereas females indicated grasses and turf. Genetically modified ornamental plants are also expected to be about the same or less invasive in the landscape than non-GM plants. Of respondents who anticipated more potential for GM ornamental plant invasiveness, women were more likely than men to predict plant escape. Men and women differed in relative acceptance of genes added from different organisms as a method of achieving genetic transformations in plants. This result suggests that outreach and marketing to promote new GM plant products should emphasize attributes of benefit rather than processes used to accomplish the goal. Regardless, although ≈73% of TN Master Gardener respondents reported interest in buying GM ornamental plants if sold commercially, participants advocated a requirement that GM plant products be clearly labeled at point-of-sale.
A new name for an old plant is not necessarily welcome in the horticultural trades or in plant identification classes, but some name changes have been in existence long enough that textbooks and trade publications should have caught up with them. The objective of this poster is to call attention to some of these changes for horticultural plant identification courses. Traditional references such as Hortus Third (1976) and Exotica 8 (Graf, 1976) have been superseded by the second edition of The Plant Book (Mabberly, 1997) and The Index of Garden Plants (Griffiths, 1994), while some recent works (The Tropical Look, Riffle, 1998) have chosen to retain old names. The taxonomic research underlying a new book, Tropical Garden Flora (Staples and Herbst, in press), based on the second edition of In Gardens of Hawaii (Neal, 1965), has produced an abundance of name changes. This poster will illustrate and report genera and species name changes that have occurred for selected ornamentals in the Acanthaceae, Agavaceae, Araceae, Araliaceae, Arecaceae, Commelinaceae, and Moraceae families plus a few others.
One of the greatest impediments to production of marketable ornamental herbaceous plants in southern U.S. is high temperature stress. Exposure of plants to sub-lethal temperature (heat preconditioning) before sustained heat stress helps some plants to tolerate subsequent heat stress a phenomenon often referred as acquired thermotolerance. The objective of this research was to examine various morphological, physiological and anatomical responses of `Vista red' (heat tolerant) and `Sizzler red'(heat sensitive) cultivars of Salvia splendens to heat preconditioning (HC) and subsequent heat stress treatments (challenging temperatures, CT). Cultivars of Salvia were subjected to short duration HC of 35 °C for 3 hours every third day until 5 weeks after germination and subsequent exposure to two CT treatments 30/23 °C and 35/28 °C (D/N) cycles in growth chambers for the next five weeks. Plant growth, marketable quality, stomatal conductance and net photosynthesis declined for Sizzler Red without HC treatment. Compared with nonpreconditioned plants, heat preconditioned Sizzler Red had 38.28% higher root dry weight, 95% greater leaf thickness, 50% higher marketable quality at 35/28 °C heat stress condition. Heat preconditioning helped both Vista Red and Sizzler to survive in both the heat stress treatments. Vista Red had greater heat tolerant traits than Sizzler Red, these traits exacerbated with heat preconditioning treatment. The results demonstrated that heat preconditioning enhanced heat tolerance in cultivars of Salvia, which could be related to maintenance of dense plant growth with shorter internodes, thicker stems, greater stomatal conductance, extensive root growth that compensated the transpirational water loss and overall cooling of plants.
While the majority of terrestial plants are colonized in soils by vesicular-arbuscular fungi (AM), that does not mean that these species can form a symbiosis with AM fungi in an artificial substrate under commercial production conditions. The purpose of this study was to identify those plants having a colonization potential. In Mar. 1998, 51 species and cultivars of ornamental plants were inoculated with two vesicular-arbuscular fungi (Glomus intraradices Schenk & Smith, and Glomus etunicatum Becker & Gerdemann; Premier Tech, Rivière-du-Loup, Quèbec). Periodic evaluations of colonization were done 5, 7, 9, 12, and 16 weeks after seeding. More than 59% of these plants tested were shown to have a good colonization potential with G. intraradices. Species belonging to the Compositae and Labiatae families all colonized. Species in the Solanaceae family showed slight to excellent colonization. Several species studied belonging to the Amaranthaceae, Capparidaceae, Caryophyllaceae, Chenopodiaceae, Cruciferae, Gentianaceae, Myrtaceae et Portulaceae families were not colonized. Root colonization with G. etunicatum was not detected on these species and cultivars during this short experimental period.
Ornamental cabbage and kale (Brassica oleracea var. acephala L.) plants of cultivars `Osaka White' and `Nagoya Red' were treated with paclobutrazol and uniconazole as foliar sprays or soil drenches. These treatments were compared to the industry standard of daminozide foliar sprays. Ten plant growth regulator (PGR) drench treatments (in mg a.i./pot) were applied 22 days after potting: paclobutrazol at 1 to 16 and uniconazole at 0.125 to 2. Thirteen PGR foliar sprays (in mg/L) were also applied: paclobutrazol at 5 to 80, uniconazole at 2 to 32, daminozide at 2500, 2500 (twice, with the second application occurring 14 days later), or 5000, and an untreated control. Applying drenches of paclobutrazol at 4 mg or uniconazole at 0.5 mg controlled height by 16 to 25%, but at the cost of $0.11 per pot would not be economically feasible for growers to use. Paclobutrazol foliar sprays at concentrations of up to 80 mg/L were ineffective in controlling plant height and diameter of either `Osaka White' or `Nagoya Red'. Uniconazole foliar sprays between 2 and 8 mg/L were effective in controlling height (by 19%) and diameter (by 15%) as daminozide foliar sprays of 2500 mg/L, sprayed twice, with a cost to the grower of $0.02 per pot.
Five woody ornamentals Rosa rugosa, Cotoneaster acutifolia, Malus baccata, Picea glauca and Pinus contorta var. latifolia, were grown for 4 seasons mulched with one of five treatments: 2.5 cm or 5 cm of crushed basaltic quarry stone, 5 cm or 10 cm of quaking aspen wood chips, and an unmulched control. Maximum soil temperatures at the 10 cm depth on the wood chip plots were decreased by as much as 8°C over control plots, and soil moisture was increased. Stone mulch plots showed a slight increase in both temperature and moisture. Soil minimum temperatures were lower on the wood chip plots than the other treatments early in the season, but were slightly higher in September. Soil pH and available N, P and K did not differ among mulch treatments. Weed growth was suppressed by all mulch treatments but was best controlled on the wood chip plots followed by the 5 cm stone plots. Plant growth for all species except Rosa rugosa was greatest on the stone mulch plots. Roses growing on the stone mulch plots and the control were subject to significant dieback from winter injury and did not show any difference in total growth after 4 years when compared with the wood chip plots. Plants grown on the wood chip plots exhibited varying degrees of nitrogen deficiency which may be related to reduced nutrient uptake in cooler soils or to a significant amount of rooting in the mulch-soil interface.
Many green-decorative branches (“Greens”) and cut flowers are commercially grown under shade nets, for both the reduction of the natural intercepted sunlight as well as physical protection. The most commonly used are black nets, which do not affect the visible light spectrum. In the work presented here we have studied the effects of shade nets of varying optical properties on the vegetative and flowering responses of ornamental plants, searching for nets that will specifically induce a desired behavior, thus gaining benefits in addition to the mere shading. Nets of different transmittance spectra, light scattering, reflectance and thermal properties are being studied for their effect on the vegetative growth of several Greens: Pittosporum variegatum, Ruscus hypoglossum, and Leather-leaf fern. The knitting density of all nets has been adjusted to have the same percent shading in the PAR (photosynthetically active radiation) range of the spectrum for all nets investigated. Experiments were carried out in commercial plots. Data were collected for microclimate, physiological and horticultural parameters. The main results obtained so far: i) pronounced stimulation of the vegetative growth under the Red net; ii) dwarfing by the Blue net; iii) the Grey net markedly enhanced branching, yielding “bushy” plants with short side branches; iv) the reflective, thermal net (Aluminet®) enhanced side, long branching (in Pittosporum). Recently we have applied a similar approach to cut flowers such as Lupinus luteus, Lisianthus eustoma, and Dubium ornitugalum, and obtained dramatic effects of some of the nets on both the vegetative development and flowering behavior. The results to be presented, suggest that sophistication of the use of shade nets can lead to better agricultural performance.