bluuebunny/crossref_metadata_2025 huggingface dataset:
Vegetative Propagation of Woody Ornamentals Through Forcing of Epicormic Shoots
Authors: Henry Paul H. , Preece John E.
Published: February 2019

A propagation method is being developed that allows softwood shoots to be generated from stem sections of dormant woody plant species. These shoots, forced in the greenhouse during the winter, are subsequently collected and processed as softwood stem cuttings to produce clonal plant material. Many species in the nursery industry can only be propagated using softwood cuttings, and this technique allows propagation of these species to be initiated several months earlier than what is typically possible. Current studies involve expanded screening of ornamental tree and shrub species to determine if commercial production using this technique is feasible. Results demonstrate that many species may be propagated using this method, but that some species are more prolific than others with respect to number of softwood shoots produced. Additional studies are currently in progress to determine the environmental (light regime, moisture regime) and cultural (type of media) conditions that are optimal when producing clonal plant material via this technique.
Redesigning the Master Plan for the South Carolina Botanical Garden
Authors: Muzii Karl J. , Haque Mary
Published: February 2019

In 1997 the South Carolina Botanical Garden determined the need to reevaluate and update the 1989 Botanical Garden Master Plan. The original comprehensive plan presented recommendations for the long-term development of the site and the facilities of the garden. Significant changes and new programs have arisen since the 1989 Master Plan was completed. Because of the new direction of programs such as the South Carolina Heritage Corridor, Southern Living Home, Conservatory and Outdoor Sculpture Program, it was necessary to develop an updated design strategy to incorporate these future plans into the South Carolina Botanical Garden. Programmatically, the idea of the South Carolina Botanical Garden is to find solace in the garden, to find a retreat from the pressures of everyday life and create a somewhat idyllic world while setting an environment for cultural and botanical conservation. The goal was allowing visitors to move throughout the garden without endangering the existing and established ornamental and native flora as well as educating its visitors. It is on this framework that the Botanical Garden Master Plan is based. The design methodology used in the development of the master plan began with staff meetings, research and site analysis. Design concepts, circulation alternatives and final design choices evolved out of subsequent staff meetings and design reviews. A booklet was also published for future development and fund raising. My presentation will outline the goals, methodology, design decisions and concepts that shaped the final master plan for the South Carolina Botanical Garden.
Ancymidol Increases In Vitro Multiplication Rate of Hosta in Liquid Media
Authors: Adelberg J. , Kroggel M.
Published: February 2019

The main and interactive effects of plant growth regulators were assayed to optimize multiplication rate for Hosta in liquid media. Two varieties of Hosta were run through three 4-week subculture cycles in shake flasks. When Hosta `Blue Cadet' was grown on three concentrations of cytokinin (1, 2.25, and 5 μM BA), three concentrations of auxin (0.1, 1.0, and 10 μM IAA), and four concentrations of an anti-gibberellin growth regulator (0.0, 0.1, 0.32, and 1.0 μM ancymidol), multiplication rates improved markedly during the first two subculture cycles in liquid, (1.7 and 3.6x, respectively) before stabilizing at third subculture. BA and ancymidol both increased multiplication rate. IAA interacted antagonistically with BA. An optimal multiplication medium with 2.25 μM BA, 1.0 μM IAA, and 1.0 μM ancymidol, provided a high rate of multiplication with well-defined shoot morphology and minimal root growth. Media consisting of 1.0 μM BA, 10.0 μM IAA, and 0.32 μM ancymidol was effective in producing leafy plantlets, with root initials, ready for transfer to mist bed acclimatization. When Hosta `Stilletto' was grown on concentrations of cytokinin (1, 2.25, and 5 μM BA), auxin (0.1, 1.0, and 10 μM IAA) and ancymidol (0.0, 1.0, and 3.2 μM), multiplication rates improved markedly during the first two subculture cycles in liquid (1.9 and 2.4x, respectively) before stabilizing at third subculture. Ancymidol increased multiplication rate at either level; the interactive effect with BA showed highest multiplication rates at lowest BA levels in the presence of ancymidol. Lower BA concentrations promoted better culture morphology and lesser BA induced root inhibition.
Creation and Maintenance of a Horticultural Education Web Site by an Extension Specialist Without HTML Programming Skills
Authors: Brandenberger L. , Lineberger D.
Published: February 2019

Informational web sites on the World Wide Web (WWW) are another means for extension educators to transfer information to a clientele and provide access to new audiences. One of the problems inherent in the utilization of this new technology is the amount of effort required by those involved in order to become proficient enough to accomplish their goal of sharing information through a web site. Through the use of a HTML editor and the assistance from staff knowledgeable about the WWW, a web site on a main campus server was created by untrained off-campus personnel at a remote site to provide information on commercial vegetable production. Planning of the web site included targeting potential audiences, determining what information would be shared from the site, and building a team of extension and research personnel that would provide information and act as reviewers for web publications. Assistance in the form of graphics and general know how were supplied by departmental specialists. After development, the web site was maintained and refined on a regular basis through the utilization of the HTML editor and a web file transfer program.
The Influence of Light and Temperature on Flowering and Growth of Angelonia angustifolia Benth.
Authors: Armitage Allan M.
Published: February 2019

Angelonia Humb.& Bonpl. (Angelonia), Scrophulariaceae, consists of about 30 species and has potential in amenity horticulture and as a pot plant. Selections of A. angustifolia Benth. and hybrids occur in several flower colors and have been evaluated for amenity purposes. Selected taxa were grown in different photoperiods (8-h, 16-h and combinations), light intensity, and temperature regimes (10–30 °C) to determine optimum environments for flowering and growth. Preliminary studies indicate that plants are only slightly responsive to photoperiod. Plants reached visible bud stage 4 to 10 days earlier in long-day treatments, but the time from visible bud to flower was unaffected. Raceme length was longer in LD plants. Plants flowered more rapidly and produced more flowers in high light and warm temperatures. Performance of plants in a landscape situation will also be discussed.
Response of Poinsettia Growth and Development to Ratio of Radiant to Thermal Energy
Authors: Liu Bin , Heins Royal D.
Published: February 2019

A concept of ratio of radiant to thermal energy (RRT) has been developed to deal with the interactive effect of light and temperature on plant growth and development. This study further confirms that RRT is a useful parameter for plant growth, development, and quality control. Based on greenhouse experiments conducted with 27 treatment combinations of temperature, light, and plant spacing, a model for poinsettia plant growth and development was constructed using the computer program STELLA II. Results from the model simulation with different levels of daily light integral, temperature, and plant spacing showed that the RRT significantly affects leaf unfolding rate when RRT is lower than 0.025 mol/degree-day per plant. Plant dry weight is highly correlated with RRT; it increases linearly as RRT increases.
Service Learning and Environmental Education
Authors: Haque Mary Taylor , Tai Lolly , VanderMey Brenda
Published: February 2019

Service learning is a teaching method that enables college students and faculty to learn while identifying and solving community problems. A case study involving the creation of sustainable landscapes for a low-income community in Clemson, S.C., will be used to illustrate the methodology necessary to complete a successful service learning project. Clemson Univ. students from four courses worked towards advancing their knowledge and commitment to environmental stewardship. They enhanced their education in landscape design and implementation through a partnership with the City of Clemson, Habitat for Humanity, the National Wildlife Federation, and others which resulted in the creation of certified backyard habitats for low-income residents.
The Effect of Media and Lime Incorporation on Growth of Three Azaleas
Authors: Knight Patricia R. , Anderson John M. , Parks Ralph A.
Published: February 2019

The influence of media and lime incorporation was investigated for a satsuki (Rhododendron eriocarpum `Pink Gumpo'), a kurume (Rhododendron obtusum `Girard's rose), and a Southern indica azalea (Rhododendron indicum `Formosa'). Uniform liners of each cultivar were planted into 2.8-L containers on 11 Apr. 1997 and placed under shade. Media evaluated included 4 pine bark (pb):0 coconut coir pith (cc), 3 pb:1 peatmoss, 3 pb:1 cc, 2 pb:2 cc, 1 pb:3 cc, and 0 pb:4 cc. Dolomitic limestone was incorporated at 0 or 1.2 kg/m3, and Micromax was incorporated at 0.6 kg/m3. Data collected included pH and electrical conductivity and growth. Liming increased pH for 4 pb:0 cc and 4 pb:1 peatmoss treatments compared to unlimed 4 pb:0 cc and 4 pb:1 peat moss treatments 0 DAT, respectively, but electrical conductivity measurements were similar. By 240 DAT, pH measurements for all treatments were similar. Medium composed of 4 pb:0 cc and dolomitic limestone had higher conductivity compared to all other treatments. Growth of Formosa was only impacted when plants grown in 3 pb:1 peat moss or 2 pb:2 cc with no dolomitic limestone were compared to plants grown in 4 pb:0 cc and dolomitic limestone. Addition of dolomitic limestone did not influence growth within any media. Growth of Girard's rose was higher for plants grown in 1 pb:3 cc regardless of dolomitic limestone amendment, and growth was lower for plants grown in 4 pb:0 cc with no dolomitic limestone although there were similarities between other treatments. Incorporation of dolomitic limestone increased growth when plants were grown in 4 pb:0 cc. Growth of pink gumpo was not influenced by media.
Effects of an Autoregulatory Senescence-inhibitor Gene Construct on Nicotiana alata Link and Otto.
Authors: Schroeder Kenneth R. , Stimart Dennis P.
Published: February 2019

Nicotiana alata Link and Otto. was transformed via Agrobacterium tumefaciens encoding a senescence-specific promoter SAG12 cloned from Arabidopsis thaliana fused to a Agrobacterium tumefaciens gene encoding isopentenyl transferase (IPT) that catalyzes cytokinin synthesis. This was considered an autoregulatory senescence-inhibitor system. In 1996, we reported delayed senescence of intact flowers by 2 to 6 d and delayed leaf senescence of transgenic vs. wild-type N. alata. Further evaluations in 1997 revealed several other interesting effects of the SAG12-IPT gene construct. Measurement of chlorophyll content of mature leaves showed higher levels of both chlorophyll a and b in transgenic material under normal fertilization and truncated fertilization regimes. At 4 to 5 months of age transgenic plants expressed differences in plant height, branching, and dry weight. Plant height was reduced by 3 to 13 cm; branch counts increased 2 to 3 fold; and shoot dry weight increased up to 11 g over wild-type N. alata. These observations indicate the system is not tightly autoregulated and may prove useful to the floriculture industry for producing compact and more floriferous plants.
Phosphorus Fertilization in Ebb and Flow Production of Bedding Plants
Authors: James Erin , van Iersel Marc
Published: February 2019

The quantity and quality of available water in the Southeastern United States continues to decline as demands on limited resources increase. Growers will soon be forced to comply with legal limitations on water consumption and limits on nutrient runoff from their operations. A lack of information on standard growing practices using alternative irrigation systems such as ebb and flow is hindering their acceptance and implementation. We are currently conducting a series of experiments to establish basic growing guidelines for the use of ebb and flow in the greenhouse in bedding plant production. In the third of these experiments, Petunia × hybrida Hort. Vilm.-Andr. `Blue Frost' and Begonia × hiemalis Fotsch. `Ambassador Scarlet' were grown for 5 weeks on ebb and flow tables with fertigation solutions (225 ppm N) containing three different levels of phosphorus (0, 50, and 100 ppm). Three soilless media were also used, which varied in their percentage content of vermiculite, perlite, pine bark and coconut coir. For both the begonias and petunias dry mass of the shoot was greatest in plants grown with higher levels of phosphorus. In comparison to plants grown with 0 ppm phosphorous, petunias and begonias grown with 50 or 100 ppm P were 44% and 25% greater in mass, respectively. However, begonias had 38% more flowers when fertigated with the higher levels of phosphorous while petunias flowered earlier with 0 ppm P fertigation solution. The electrical conductivity of the media did not change significantly over the course of the growing period, but the pH dropped by an average of 1 over the same time interval.
Budbreak of Rabbiteye Blueberry Enhanced by Hydrogen Cyanamide
Authors: Hall Melvin R. , Austin Max E.
Published: February 2019

Few flower buds on pot grown `T-227' rabbiteye blueberry (Vaccinium ashei Reade) advanced past stage 1 (tight bud) when exposed to 0 or 200 h of chilling temperatures (4 °C), regardless of treatment with hydrogen cyanamide. However, 0.25%, 0.5%, 1%, and 2% sprays on plants chilled 400 h advanced flower bud development through stage 6 (open). Sprays were less effective on plants chilled for 600 h or longer, and 1% and 2% sprays caused some phytotoxicity regardless of chilling.
Development of REDCAHOR—a Vegetable Research and Development Network in Central America
Authors: Nienhuis J.
Published: February 2019

REDCAHOR is the Spanish acronym for “Central American Vegetable Network.” Vegetables have traditionally been an important source of nutrients and vitamins in the diet in Central America. Vegetable production in this region is now changing as local consumers are demanding increased diversity and quality and international markets are expanding with “non-traditional” vegetable exports. The present restraints to expanded research and production of vegetables in the region include i) need for cultivars with increased insect and disease resistance, ii) poor and excessive use of pesticides, and iii) inadequate postharvest technology. In addition, there are few vegetable researchers in the region and response to their activities have not been coordinated. The goal of REDCAHOR is to develop a regional network of national institutions that can prioritize agendas and cooperate to maximize the impact of available resources. Establishment of a system of regional trials and cooperative regional programs in integrated pest management and plant breeding are currently under development. A series of regional workshops are planned, including integrated pest management, maintenance and use of genetic resources, organic production, and greenhouse production. In addition, REDCAHOR, in collaboration with the Escuela Agricola Panamerica in Honduras, will offer regional short-course training in vegetable breeding and genetics as well as vegetable production and management, including integrated pest management.
Advanced Selections of Summer Apples from the Arkansas Apple Breeding Program
Authors: Rom Curt R. , Rom R.C. , Moore J.N. , Clark J.R.
Published: February 2019

An apple breeding program was begun in Arkansas in 1966 with objectives including the development of early maturing cultivars adaptable to warm environments. Several advanced selections have achieved this objective and are briefly described here prior to possible introduction as new cultivars. AA-50 (PCR3-120 × PCR4-56) mature 65–75 days after bloom, are moderate size (120–160 g), round, tart, juicy; red over green/white ground color. Fruit are similar to `Jonathan'. AA-63 (Jersey Mac × AA-11) mature 70–85 days after bloom, are moderate size (130–180 g), round, somewhat tart but with good sugars for maturation season, are dark red/purple striped with pronounced lenticels on a green/white ground color. AA-18, aka `Arkcharm' (NJ123249 × NJ136055) ripen 85–100 days after bloom, are medium to large size (165–195 g), slightly conic, bright red on green ground/yellow color, are very crisp and firm, tart with good flavor, good shelf-life for season (7–21 days) and extended harvest period (two to three harvests). AA-44 (NJ674016 × NJ40), mature 90–105 days after bloom, are large (180–210 g), round, red with some dark red striping with green ground color; fruit have moderate acid content and are relatively sweet, require two to three harvests and have a storage life of 2–4 weeks. AA-64 (SpurGold × AA-26) mature 110–120 days after bloom, are yellow, conic, russet free, often have a pink blush, are moderate to large size (160–200 g), firm, subacid, and sweet.
Environmental and Genetic Factors Affects Frequency of Tetraploid Regenerants from Immature Cotyledons of Melon
Authors: Adelberg J. , Chen J.
Published: February 2019

Immature cotyledons of three inbred melon genotypes, Cucumis melo L., and all hybrid cross-combinations were placed for a 1-week treatment on liquid/membrane system prior to 5-week regeneration culture on a MS medium containing 10 μM benzyladenine. Moving plants from agar to liquid/membrane culture system altered the frequency of tetraploid regenerants. The frequency of tetraploidy was also effected by sucrose level during the 1-week liquid treatment. The most stressful conditions, those where the least regenerants were found, had the highest number frequency of tetraploidy. Genotypic variation in the modes of genetic control was observed in the different environments. Tetraploid variation can be manipulated by one week treatment of immature cotyledons prior to regeneration.
Precision Planting for sh2 Sweet Corn Stand Establishment
Authors: Barr Amy , Bennett Mark
Published: February 2019

The impact of soil type and planting depths on the emergence of three hybrids of shrunken 2 sweet corn with varying seed vigor was investigated. Two field trials were completed (planted on 18 Sept. 1996 and 6 May 1997) in a field containing Crosby and Kokomo soil types in Columbus, Ohio. Three sh2 hybrids (`Starship', `Skyline', and `Confection') were planted at 1.3-, 2.5-, and 5.1-cm depths with six replications on each of the two soils in the fall study. The same hybrids were planted the following spring with an adjustment to 2-, 4-, and 6-cm planting depths over the same soil types, and the addition of a transition soil. The use of data loggers in 1997 allowed for continual monitoring of soil temperatures at each of the planting depths throughout the field, and calculation of soil heat units throughout the emergence period. There were no significant differences between depths for average temperatures or soil heat units. Minimum temperatures were significantly colder on the lighter color soil and had a linear relationship with emergence counts. Soil tests were carried out at all sites for P, K, Mg, and Ca. Although significant differences were found with the Kokomo soil having higher nutrient levels than the transition or Crosby soil, levels throughout the field were more than adequate for emergence. Compaction and soil moisture measurements were taken with a neutron probe. Dry density was significantly higher on the lighter color soils, while soil moisture percentage climbed from 18% on Crosby to 25% on the Kokomo. In both years, there were significant differences in emergence indices based not only on hybrid and planting depth but also on location. Emergence ranged from below 50% to nearly 100% depending on the treatment and field location. Each of the 108 sampling points was located with a GPS receiver and the use of ArcView software allowed for data layers to be stored and mapped so that prescriptions could be made for best stand establishment.
Occurrence and Development of a Dorsal Gland in the Leaves of Twelve Cultivars of Ficus benjamina L. (Weeping Fig)
Authors: Pennisi Svoboda V. , McConnell Dennis B. , Henley Richard W.
Published: February 2019

Ficus benjamina plants are an integral part of most modern interior landscapes. Reports from growers and interiorscape managers have drawn attention to a specific problem related to large F. benjamina plants, namely the occurrence of a dark oval spot on the abaxial surface of the leaf base. Twelve cultivars of F. benjamina were examined: Christine, Citation, Florida Spire, Kelly, Kiki, Midnight, Monique, Stacey, Wintergreen, Dwarf Nikita, Spearmint, and Starlight. Anatomically, the dorsal gland consisted of one to several layers of densely stained, columnar cells. Positive colorimetric reaction for phenolics was obtained in the glandular cells. Developmentally, the gland cells could not be distinguished from the regular epidermal cells until ≈30% of final leaf size was reached. The cells of the outermost glandular layer changed shape from rectangular with long axis parallel to the leaf surface to elongate with long axis perpendicular to the surface. In a mature leaf, the thickness of the glandular layer was between 20 and 30 μm. Externally, at this stage, no dark spot, indicative of the gland's location, could be observed. In older leaves, however, an accumulation of phenolic substances led to appearance of dorsal dark spot. All cultivars possessed glandular layer. However, this area did not darken in all cultivars; Christine, Citation, Florida Spire, Kelly, Kiki, and Stacey developed small dark spots, while Dwarf Nikita and Starlight had numerous, well-pronounced glandular regions. This study showed that the dark spots in F. benjamina cultivars were a normal morphological feature. Although the gland was present in every cultivar, only a few cultivars developed a dark color.
Urban Influences on Local Plant Hardiness Zones
Authors: Harp Derald A. , McWilliams Edward L.
Published: February 2019

The combination of concrete, asphalt, large buildings, lack of surface water, and heat inputs from industry, automobiles, and poorly insulated buildings result in warmer temperatures in urban environments. This effect is most pronounced in winter minimum temperatures and may cause changes in local plant hardiness zone designations. We obtained minimum temperatures for the years 1974–96 from NOAA and the Office of the State Climatologist of Texas for all recording stations in the counties in and immediately adjacent to the Dallas/Fort Worth, Texas (D/FW), metroplex to compare to the 1990 USDA plant hardiness zone map. These data were averaged and analyzed in two groups, 1974–86, which correspond to the 1990 USDA map, and the subsequent years, 1987–96. Stations that did not include a minimum of 15 years of data or anomalies that could be attributed to microclimatic phenomena were discarded. Minimum temperatures were averaged and a contour map was created using TNT Lite software. This map was overlaid on a TIGER map that included county lines and major roadways. The 1974–86 map illustrated only one discrepancy with the 1990 USDA map, the inclusion of 8a temperatures for most of the Tarrant county. Changes in the 1987–96 map included the further expansion of 8a westward into Parker county and an 8b zone in the downtown/Love Field area of Dallas. These changes corresponded well with increased construction and human activity in these areas over the past decade. These changes also help explain variations in low-temperature damage of several ornamental plant species reported in previous studies.
Carbohydrate Metabolism of Vegetative and Reproductive Sinks in the Late-maturing Cultivar Encore
Authors: Bianco Riccardo Lo , Rieger Mark , Sung Shi-Jean S.
Published: February 2019

Activities of major sorbitol and sucrose metabolizing enzymes and carbohydrate contents were followed during the growth season of `Encore' peach fruits and developing shoot tips. In fruit flesh, sucrose synthase (SS) was present during stage I of growth, when cells are actively dividing, and NAD+-dependent sorbitol dehydrogenase (SDH) during stage III, when cells enlarge actively. Acid invertase (AI) revealed the best correlation with relative growth rate (RGR) of fruits during the entire season. Activities of all carbohydrate metabolizing enzymes were not detectable in fruit flesh during seed filling and pit hardening, when RGR of fruits was the slowest. The highest content of sucrose was in concert with low levels of sucrose metabolizing enzyme activities toward the end of fruit development. In shoot tips, SDH had low activity at the beginning and end of the season when vegetative growth was slowest and a 2:1 sorbitol: sucrose ratio was present. Mid-growing season was, on the other hand, characterized by an increase in SDH activity and a 1:1 sorbitol: sucrose ratio. In `Nemaguard' seedlings, only SDH activity showed a positive correlation with shoot growth. Also, in root tips of `Nemaguard' seedlings SDH exhibited its highest activity, even higher than AI activity in the same roots. We concluded that in peach sucrose may represent the major carbon form used for fruit growth, while sorbitol seems to play a predominant role in vegetative growth.
Winter Bud Cold-hardiness of Interstem Peach Trees
Authors: Reighard Gregory L. , Ouellette David R.
Published: February 2019

Large fluctuations in annual peach production is a chronic problem in the southeastern United States. Winter and spring cold injury to flowers reduces the potential peach crop almost every year in the Southeast. A bloom delaying peach interstem has consistently delayed phenology in the Southeast, but its effect on bud hardiness is unknown. Nine varieties (650–1050 chill hours) budded to `Ta Tao 5' (P.I. 101667) interstems on Lovell rootstock or budded to only Lovell rootstock (i.e., controls) were sampled monthly from November or December to late February in 1996–97 and 1997–98 from an interstem test established in 1993 near Clemson, S.C. High-chill varieties such as `Contender', `Encore', and `Redhaven' were 1 to 2 °C more cold-hardy on interstem trees in late winter. General trends showed that varieties were slightly more cold-hardy on interstems in 1996–97, but no differences were observed from Nov.1997 through early Jan. 1998. Significant varietal differences in cold-hardiness were found on each sampling date, but no trends were observed.
Postharvest Application of Calcium to Whole Muskmelon Fruits
Authors: Lester Gene , Grusak Michale
Published: February 2019

Fully mature, abscised, hybrid netted- and honey dew-muskmelon fruits submerged in amino acid-calcium (AA-Ca) chelate solutions, vs. non-calcium treated fruits, were less senescent and had little or no surface decay following 21 days at 10 °C (honey dew) or 4C (netted) plus 3 days at 21 °C. Honey dew fruits submerged in either AA-Ca or AA-Ca plus AA-Mg, and netted fruits in AA-Ca plus AA-Mg, had hypodermal-mesocarp tissue [Ca2+] of 6.0 mg per g dry mass or higher 10 days postharvest, which is statistically similar to [Ca2+] in freshly harvested fruits. Non-calcium treated vs. calcium treated fruits, 10 days postharvest, had significantly less 6.0 mg per g dry mass [Ca2+]. Maintaining muskmelon hypodermal-mesocarp tissue [Ca2+] at 6.0 mg per g dry mass or higher maintained membrane integrity as evidenced by low free sterol: total phospholipid ratio (mol:mol), low electrolyte leakage, high total and specific H+- ATPase activities, and low lipoxygenase activity; maintained fruit firmness; and extended fruit storage life 2.4-fold (i.e., to 24 days) vs. non-calcium treated fruits. Application of calcium to abscised, fully ripe honey dew and netted muskmelon fruits should reduce fruit senescence rate in storage and should promote extended market-life and a higher quality product.
Winter Production of `Galia' Muskmelons in Northern Florida Using Protective Structures and Soilless Culture
Authors: Waldo Eric A. , Hochmuth George J. , Cantliffe Daniel J. , Sargent Steven A.
Published: February 2019

Vegetable production in southern Florida is being displaced northward due to escalating land prices. In order to produce vegetable crops in northern Florida during the cooler months when southern Florida has traditionally captured the winter market, methods of protecting crops from the cold must be investigated. In addition, the impending ban of methyl bromide in 2001 under the Clean Air Act mandates research on alternative crop production methods not requiring this soil fumigant. We grew `Galia' muskmelons [Cucumis melo var. reticulatus (L.)] under walk-in tunnels and low-tunnels (rowcovers) during the Winter/Spring of 1997 and the Fall/Winter/Spring of 1997–1998. The walk-in tunnels were quonset style structures, 10 by 20 m, covered with a single layer of polyethylene film. Three of the six walk-in tunnels had a passive heating system consisting of four water tubes each 30.5 cm in diameter and 15.25 m long, which absorbed solar energy and released it as thermal energy during cool nights. Half of all melons in each tunnel treatment were grown hydroponically in bags of perlite; the other half were grown in mulched, raised soil beds. In Spring 1997 experiment, early yield, total marketable yield, soluble solids concentration, and average fruit weight were greater with passively heated and unheated walk-in tunnels than with low-tunnels. Total marketable yield and average fruit mass were greater for melons grown in soil than for melons grown in perlite. Soluble solids concentrations were similar for melons grown in soil and perlite.
Foliar Urea Can Supplement Soil-applied Fertilizer in an Early Maturing Peach
Authors: Johnson R.S. , Rosecrance R.C. , Andris H.L.
Published: February 2019

Despite early studies that suggested foliar urea was ineffective in supplying nitrogen to peach trees, recent studies have shown rapid uptake of low biuret urea by peach leaves and subsequent mobilization to perennial tree parts. Labeled nitrogen experiments have demonstrated the distribution of N among organs to be very similar whether the N is supplied from foliar urea or from soil-applied fertilizer. However, questions still remain concerning the long-term productivity of trees treated repeatedly with foliar urea. Our first experiment was conducted on an early ripening peach, which generally requires about 100 kg N/ha applied to the soil. The treatment to replace all soil applied N with two or three foliar applications of urea in the fall resulted in similar N distribution throughout the tree and equal vegetative growth. However, fruit size was consistently smaller than the soil-fertilized control over a 3-year period. Our second experiment, conducted on the same variety, imposed a treatment to supplement about half the soil applied fertilizer with fall foliar urea applications. This treatment was able to maintain fruit size and yield over a 2-year period. Furthermore, vegetative growth was reduced compared to the soil-fertilized control, suggesting foliar urea may be a useful tool to help manipulate the distribution of growth between reproductive and vegetative processes.
Effects of Drought and Elevated Soil Temperature on Apple Root Lifespan
Authors: Eissenstat D.M. , Wang Liqin , Flores-Alva D.E.
Published: February 2019

Root lifespan has important consequences for plant growth and productivity, plant competition, and nutrient cycling. However, compared to aboveground parts, much less is know about root systems. Root dynamics of `Red Chief' Delicious on M26 rootstock trained on a trellis were examined near State College, Pa., using minirhizotrons. Soil was heated 5 °C above ambient at a depth of 5 cm by circulating hot water over a stainless steel grid on the soil surface. Soil temperature (by thermocouples) and soil moisture (by TDR) were monitored to a depth of 1 m. Root birth rate peaked between late May and mid-June, during a period of rapid shoot elongation and fruit expansion. Death rate was highest in July. There was no evidence of alternate growth between roots and shoots. Drought and elevated soil temperature increased root mortality. Median lifespan of fine roots near the soil surface (<20 cm) was least in the heated-drought treatment (30 d) and longest in the unheated-irrigated treatment (56 d). Heating caused substantial increases in root birth rate, thus, causing higher populations in the heated than unheated treatments despite the increased root death rate in the heated soil.
Evapotranspiration Measurement and Irrigation Scheduling for Several Tropical Fruit Crops Using the EnviroScan System
Authors: Zekri Mongi , Schaffer Bruce , O'Hair Stephen K. , Nunez-Elisea Roberto , Crane Jonathan H.
Published: February 2019

In southern Florida, most tropical fruit crops between Biscayne and Everglades National Parks are irrigated at rates and frequencies based on experience and observations of tree growth and fruit yield rather than on reliable quantitative information of actual water use. This approach suggests that irrigation rates may be excessive and could lead to leaching of agricultural chemicals into the groundwater in this environmentally sensitive area. Therefore, a study is being conducted to increase water use efficiency and optimize irrigation by accurately scheduling irrigation using a very effective management tool (EnviroScan, Sentek Environmental Innovations, Pty., Kent, Australia) that continuously monitors soil water content with highly accurate capacitance multi-sensor probes installed at several depths within the soil profile. The system measures crop water use by monitoring soil water depletion rates and allows the maintenance of soil water content within the optimum range (below field capacity and well above the onset of plant water stress). The study is being conducted in growers' orchards with three tropical fruit crops (avocado, carambola, and `Tahiti' lime) to facilitate rapid adoption and utilization of research results.
The Development of Horticulture Software on Landscape Plants
Authors: Kling Gary J.
Published: February 2019

This presentation will cover some of the major decisions that were made in the development and modification of software to provide horticultural resources for college students and members of the industry. Technological changes have moved the production from video-disc technology to server-based digital formats, CD-ROM, and the World Wide Web. Each of these changes results in a different product suited to different audiences. The current stage of product development will be presented.
Designing and Evaluating Survey Instruments for Research in Human Issues in Horticulture
Authors: Skelly Sonja M. , Bradley Jennifer Campbell
Published: February 2019

Survey research has a long precedence of use in the social sciences. With a growing interest in the area of social science research in horticulture, survey methodology needs to be explored. In order to conduct proper and accurate survey research, a valid and reliable instrument must be used. In many cases, however, an existing measurement tool that is designed for specific research variables is unavailable thus, an understanding of how to design and evaluate a survey instrument is necessary. Currently, there are no guidelines in horticulture research for developing survey instruments for use with human subjects. This presents a problem when attempting to compare and reference similar research. This workshop will explore the methodology involved in preparing a survey instrument; topics covered will include defining objectives for the survey, constructing questions, pilot testing the survey, and obtaining reliability and validity information. In addition to these topics some examples will be provided which will illustrate how to complete these steps. At the conclusion of this session a discussion will be initiated for others to share information and experiences dealing with creating survey instruments.
Current Practices in the Evaluation of Teaching in Horticulture
Authors: Hughes Harrison
Published: February 2019

Universities offering horticulture curriculum were surveyed for procedures for evaluation of teaching. They were asked to indicate which of the following were used to evaluate instructors: student surverys, peer reviews, administrator reviews, alumni surveys, and others. They were also asked the criteria which were used in these evaluations; i.e., instructor was well-prepared, class presentations were clear and well-organized etc. Many programs used student surveys as the prime means of evaluations of instructors. Some used peer evaluation as well and a few used alumni surveys. Several indicated that they were currently reviewing their process of instructor evaluation.
Optimizing Graft Union Formation between Sweetpotato (Ipomoea batatas) and Bush Morning Glory (Ipomoea carnea ssp. fistulosa) as a Prelude to Chimera Development
Authors: Maxwell Douglas W.
Published: February 2019

Bush morning glory (Ipomoea carnea ssp. fistulosa) and ornamental sweetpotato (Ipomoea batatas `Blackie') were grafted using various procedures. Lanolin pastes containing 3% BA, 3% NAA, and a mixture of 3% BA/3% NAA were tested as a means of promoting adventitious shoot development at the graft union. Excellent “take” was obtained with all graft types tested. The growth regulator treatments resulted in marked differences in callus formation at the wounded graft union. Lateral shoot development below the graft union also was affected by the growth regulator treatments. The highest quantity of callus was formed using the mixed paste, while BA enhanced lateral shoot formation below the union. Results indicate that in-vivo grafting of these two species may not be the best procedure for obtaining interspecific chimeras.
Differential Interaction of Apple Cultivars and Spider Mites (Acari: Tetranychidae)
Authors: Ravi Jayasree , Johnson Donn T. , Lewis Barbara A. , Rom Curt R.
Published: February 2019

In 1995, greenhouse and orchard experiments of 11 apple cultivars were conducted in Fayetteville and Clarksville, Ark. Weekly cumulative mite days (CMD) were regressed against leaf bronzing (colorimeter value L) and compared among cultivars. European red mites, Panonychus ulmi and two-spotted spider mites, Tetranychus urticae, were found on leaves. `Liberty', `Royal Gala', and `Stark Spur Red Rome Beauty' had significantly more mites (>1940 CMD) than did `Arkansas Black' (1303), `Jonafree' (1150), and `Northern Spy' (973). A low CMD on `Northern Spy' caused leaves to bronze faster [y = 29.04 + 0.006(x); R2 = 52, P = 0.0002] than did a high CMD on `Liberty' [y = 30.41 + 0.0027(x); R2= 70, P = 0.0001]. Field estimates were made of spider mites/leaf and bronzing from 20 June to 7 Aug. `Stark Spur Red Rome Beauty' and `Stark Spur Law Rome' had significantly more CMD than did `Northern Spy' and `Arkansas Black'. Apple cultivars differed in carrying capacity to mites (susceptibility) and how fast leaves bronze in response to mite feeding. Cultivar differences in hairiness of the lower leaf surface were not correlated to CMD.
Louisiana Select: Taking the Plants to the People
Authors: Owings Allen D.
Published: February 2019

The LSU Agricultural Center and Louisiana Association of Nurserymen initiated an ornamental plant promotion and recommendation program in 1996. Called `Louisiana Select', this program is intended to actively promote outstanding ornamental plants to Louisiana's gardening consumers. Plants are promoted in the spring and fall of each year and have included `New Orleans Red' coleus, mayhaw, `Henry's Garnet' Virginia willow, `Homestead Purple' verbena, `Watchet' azalea, `Telstar' dianthus, bald cypress, `New Wonder' scaevola, “Fall is for Planting Native Trees”, and lantana (`New Gold', `Dallas Red', `Confetti', `Trailing Purple', and `Silver Mound'). Point of purchase signs and banners promoting the `Louisiana Select' program and individual plants are provided to retail garden centers. Significant sales increases ranging from 300% to 2500% have been reported for the selected plants, with annual bedding plants and perennial flowers enjoying the greater sales increases. Plants for promotion are selected by a committee of wholesale greenhouse producers, retailers, landscape contractors, and cooperative extension service personnel.
Postharvest Waste is a Serious Problem in Developing Countries
Authors: Basiouny Fouad M
Published: February 2019

Postharvest waste constitutes major problems in developing countries and usually results in significant waste of produce valued in the millions of dollars. Lack of disease control, proper fertilization, irrigation and improper cultural practices during the growing season followed by faulty handling methods during and after harvest are different factors contributing to poor quality, short shelf-life, and fast deterioration of the produce. In spite of the utilization of advanced technologies, postharvest loss in developing nations may range from 20% to 80%, depending on the commodity and the producing country. Due to the magnitude of the problem, serious efforts must be directed to improve production and reduce postharvest waste in nonindustrialized nations.
Susceptibility of Pecan to Black Pecan Aphids
Authors: Wood Bruce W. , Reilly Charles C.
Published: February 2019

The host-parasite interaction between the black pecan aphid (BPA) [Melanocallis caryaefoliae (Davis)] and pecan [Carya illinoensis (Wangenh.) K. Koch] was investigated. Three years of field observations of the ability of BPA populations to induce chlorotic blotches, or visual damage, on 32 pecan cultivars revealed considerable variation in cultivar susceptibility to BPA damage. Among the most commonly grown cultivars, `Sioux', `Cape Fear', `Farley', `Cowley', `Grabohls', and `Barton' exhibited the least damage, whereas `Choctaw', `Oconee', and `Sumner' exhibited the greatest, with `Sioux' and `Choctaw' exhibiting the greatest extremes in susceptibility. Subsequent evaluation indicated that the foliage of pecan genotypes can exhibit an antibiotic-like effect, resulting in the suppression of resident BPA populations. However, the relationship between the degree of this antibiotic effect and the degree of damage exhibited by trees, or field tolerance, was negligible (r = -0.10). For example, while `Choctaw' foliage greatly suppressed BPA population growth, this population was able to inflict relatively severe damage to leaves. An evaluation of feeding preference indicated that BPA alate viviparae (winged females) preferentially feed upon host cultivars on which they have been previously feeding. This feeding preference was eliminated by rinsing leaves with distilled water; hence, a water soluble factor(s) appears to be involved in host preference.
Vine Management Systems Affect Yield, Fruit Quality, Cluster Compactness, and Fruit Rot of `Chardonnay' Grape
Authors: Zabadal Thomas J. , Dittmer Thomas W.
Published: February 2019

Three vine management systems were evaluated on `Chardonnay' grapevines under Michigan growing conditions for five growing seasons to determine their influence on yield, fruit quality, cluster compactness, and the incidence and severity of fruit rot. These systems used mid-wire cordon (MWC) vine training, Umbrella Kniffin (UK) vine training, and a combination of those (UK/MWC). Over four growing seasons the UK and UK/MWC treatments had higher fruit soluble solids and higher yields than the MWC treatment. These higher yields were attributed to higher yields per node and the ability to retain more live nodes per vine than was possible with the MWC treatment. The UK and UK/MWC treatments also had less fruit rot than the MWC treatment in some years, which was related to reduced compactness of clusters. The UK and UK/MWC treatments produced greater numbers of mature canes per vine than the MWC treatment, and the locations of the canes allowed full cropping the season following an extremely cold winter.
Biostimulants and Soil Amendments Affect Two-year Posttransplant Growth of Red Maple and Washington Hawthorn
Authors: Kelting Matt , Harris J. Roger , Fanelli Jody , Appleton Bonnie
Published: February 2019

Humate-based products have been aggressively marketed as biostimulants that increase plant growth. Little data are available on their effect on tree establishment or their interaction with fertilizer and irrigation regimes. This experiment tested several types of biostimulants on posttransplant growth of Acer rubrum L. (red maple) and Crataegus phaenopyrum (Blume) Hara (Washington hawthorn) trees, both with and without irrigation and fertilization. Soil treatments were applied at planting as: 1) control (native backfill only); 2) compost (native backfill + yard-waste compost); 3) peat (native backfill + Canadian sphagnum peat); 4) granular humate, 100 g/tree; 5) granular humate, 200 g/tree; and 6) liquid humate +, a proprietary liquid mixture of humate, kelp extract, thiamine, and intermediate “metabolites.” Irrigation regime × soil treatment interaction was significant for red maple, but soil treatments did not increase height, stem diameter, top dry mass, or root length. For Washington hawthorn, soil treatments did not increase height, stem diameter, or root length, but top dry mass in all treatments as a group and in humate-treated trees in particular was greater than that of controls. Roots of peat-treated trees of both species were longer than those in other treatments. Granular humate applied at 200 g/tree increased total root length more than did 100 g/tree in Washington hawthorn but not in red maple. Fertilizing at planting with N at 14.5 g·m-2 had no effect on any parameter measured for either species.
DRIS Evaluation of the Nutritional Status of Processing Tomato
Authors: Hartz T.K. , Miyao E.M. , Valencia J.G.
Published: February 2019

Diagnosis and Recommendation Integrated System (DRIS) norms were derived for processing tomato (Lycopersicon esculentum Mill.) from a 1993-94 survey of >100 fields in the Sacramento and San Joaquin Valleys of California. Relative foliar N, P, K, Ca, Mg, and S concentrations were expressed in ratio form, with DRIS norms calculated as the means of fields with fruit yield ≥90 Mg·ha-1. Norms were developed for three growth stages: first bloom, full bloom, and 10% of fruits ripe. Optimum foliar nutrient concentration ranges were calculated by regression analysis from DRIS nutrient indices of high-yield fields. These optimum ranges were in general agreement with existing empirically derived sufficiency ranges for N and P, higher for Ca, Mg, and S, and much lower for K. The relatively low foliar K levels observed were attributed primarily to the strongly determinate growth habit of currently used cultivars. In the fields sampled, yield-limiting nutrient deficiency appeared to be rare.