bluuebunny/crossref_metadata_2025 huggingface dataset:
Mowing Height, Nitrogen Rate, and Biostimulant Influence Root Development of Field-grown `TifEagle' Bermudagrass
Authors: Tucker Brian J. , McCarty Lambert B. , Liu Haibo , Wells Christina E. , Rieck James R.
Published: February 2019

As golfers demand higher quality golf green putting surfaces, researchers continue to seek improved turfgrass cultivars. One such improved cultivar is `TifEagle' bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy], which is an improvement over traditional bermudagrass cultivars such as `Tifgreen' and `Tifdwarf' due to its ability to tolerate mowing heights of ≤3.2 mm for extended periods. One observed disadvantage of `TifEagle' is its lack of a deep, dense root system compared to previous bermudagrass cultivars. This field study measured mowing height, N rate, and biostimulant product effects on `TifEagle' rooting. Three mowing heights (3.2, 4.0, and 4.8 mm), three N rates (12, 24, and 48 kg N/ha/week), and two cytokinin-containing commercial biostimulant products (BIO1 and BIO2) were examined. Plant responses measured were root length density (RLD), root surface area (RSA), thatch layer depth (TLD), and turf quality (TQ). Increasing mowing height from 3.2 to 4.0 mm increased RLD by >11%, RSA by >11%, and TQ by >17%. Increasing N rates from 12 to 24 kg N ha-1 week-1 increased RLD by >17%, RSA by >26% and TQ by >16%. No effect on RLD was observed after the first year of biostimulant use, however, after the second year, BIO1 increased RLD by >11% when applied with the lowest rate of N (12 kg N/ha/week). Higher mowing heights (4.8 and 4.0 mm) increased TLD >6% compared to the lowest mowing height (3.2 mm), and higher N rates (48 and 24 kg N/ha/week) increased TLD >3% compared to the lowest N rate (12 kg N/ha/week). Overall, a mowing heights ≥4.0 mm, N rates ≥24 kg N/ha/week, and long-term use of a cytokinins-containing biostimulant had a positive effect on `TifEagle' rooting.
A Nuclear Magnetic Resonance Spectroscopy-based Approach to Profile Biologically Active Plant Metabolites Using Black Raspberry Inhibition of Colon Cancer Cell Proliferation as a Model System
Authors: Wyzgoski Faith J. , Miller A. Raymond , Scheerens Joseph C. , Rinaldi Peter L. , Bishop Bert L. , Reese R. Neil , Ozgen Mustafa , Tulio Artemio Z. , Giusti M. Monica , Bomser Joshua A.
Published: February 2019

We have developed a Nuclear Magnetic Resonance (NMR)-based approach to metabolomics research that enables the identification of bioactive compounds in crude plant extracts. For this work, we used black raspberries, which are known to contain compounds that exhibit chemopreventive activity toward oral, esophageal, and colon cancers. To ascertain bioactive components and their interrelationships, NMR results for black raspberry samples from four cultivars grown on commercial farms in Ohio were examined using principal component analysis. Multivariate analysis that included anthocyanin content (HPLC), antioxidant activity (DPPH, ABTS, FRAP), total phenolics (Folin-Ciocalteau assay), and bioactivity as measured by inhibition of colon cancer HT-29 cell line proliferation showed correlations with specific regions of NMR spectra at 400 MHz. Correlations were also observed for major and minor groupings of the black raspberry samples. Replicate black raspberry samples were examined with a 750 MHz NMR spectrometer equipped with a cryoprobe that provided a 4- to 5-fold improvement in sensitivity. In this manner, even minor bioactive components in black raspberries could be examined to determine additive and synergistic effects.
Fertilizer Source and High Tunnel Production Environment Affect Antioxidant Levels of Pac Choi
Authors: Zhao Xin , Carey Edward E. , Iwamoto Takeo
Published: February 2019

An experiment was conducted at Olathe, Kan., in Spring 2004 to investigate the influence of organic and conventional fertilizer sources and application rates on antioxidant levels of pac choi (Brassica rapa L. cv. Mei Qing) in open fields and poly-covered high-tunnel plots. Organic plots received pre-plant application of composted cattle manure and alfalfa (Hu-More 1–1–1) at 0 kg/ha N, 156 kg/ha N, or 314 kg/ha N, and conventional plots received preplant application of 13N–13P–13K at 0 kg/ha N, 78 kg/ha N, or 156 kg/ha N. Antioxidant levels were measured using the oxygen radical absorbance capacity (ORAC) assay. There were significant effects of fertilizer source and high-tunnel environment on the antioxidant capacity of pac choi. Organic fertilization significantly increased hydrophilic ORAC of pac choi in open field plots, but not in high tunnels. Regardless of the fertilizer source, pac choi grown in the open field had significantly higher hydrophilic ORAC than that grown in tunnels. Lipophilic ORAC was significantly increased by organic fertilization but was not affected by high-tunnel production. Total ORAC (hydrophilic + lipophilic) was significantly higher in pac choi from organic or open-field plots, compared to conventional and high-tunnel plots, respectively. Although fertilizer rate did not show significant impact on antioxidant level of pac choi, hydrophilic and total ORAC seemed to decrease as the fertilizer rate increased, especially under conventional fertilization, while lipophilic ORAC reached the highest level at the medium fertilizer rate. Differences in antioxidant levels were likely associated with the enhanced phytochemical content of pac choi from organically fertilized and open-field plots.
The Response of Basil Accessions to Date of Planting in North Alabama
Authors: Sims Cedric A. , Mentreddy Srinivasa R.
Published: February 2019

Basil (Ocimum sp.), belonging to the mint family, Lamiaceae (Labiatae), is a popular herb grown for the fresh market or for its dried aromatic leaves, which are used as a spice or in potpourris. In Asian countries, basil, particularly O. tenuiflorum, is better known as a medicinal plant species used for treating ailments ranging from colds to complex diseases such as cancers and diabetes. In the United States, however, it has a limited acceptance as a fresh-market herb. There is much potential for developing basil as a medicinal plant to cater to the growing herbal medicinal products industry. A field trial was therefore conducted to determine optimum date of planting basil in Alabama. Six-week-old seedlings were transplanted from the greenhouse into field plots arranged in a split-plot design with four replications. Planting dates at monthly intervals beginning in April were the main plots and three Ocimum accessions, Ames 23154, Ames 23155, and PI 288779 were sub-plot treatments. The accessions were compared for growth, leaf area development, light interception, canopy cover, and dry matter accumulation and partitioning pattern over planting dates. Ames 23154, with greater canopy cover (98.5%) and photosynthetically active radiation interception (96.1%), also produced higher total plant biomass than other accessions. Accession PI 288779 appeared to partition greater dry matter to leaves, which are the primary source of bioactive compounds in basil. Among planting dates, second (May) date of planting appeared to be optimum for both total biomass and leaf dry matter production. Genotypic variation f or dry-matter partitioning and relationships among agronomic parameters as influenced by planting date will be discussed in this presentation.
Using Active Learning to Teach Irrigation Concepts in Greenhouse Management
Authors: Burnett Stephanie , Zhang Donglin
Published: February 2019

In the past, horticulture students at the University of Maine have been taught to irrigate plants using only hand irrigation. It is becoming increasingly important to irrigate and fertilize efficiently in commercial greenhouses in order to reduce water waste and nutrient leaching. In 2004 and 2006, greenhouse management or plant production students were exposed to alternate methods of irrigating Dendranthema ×morifolium (chrysanthemum) in greenhouses to train students more effectively in irrigation techniques. In 2004, students measured the quantity of water applied to chrysanthemums once they reached the permanent wilting point from 26 Sept. until 30 Oct. The irrigation frequency generally increased as crops grew, but, the quantity of water applied upon irrigation was not significantly different. This experience provided students with a tangible idea of how irrigation frequency and timing change as crops grow, which could be applied to irrigation timing decisions in the future. In 2006, students grew a crop of chrysanthemums using alternate methods of irrigation (hand watering vs. drip irrigation) and fertilization. Student surveys in 2006 indicated that only 25% of students with previous experience working in a greenhouse or nursery had grown crops using drip irrigation, but all students with prior experience had irrigated by hand. Expanding student experiences with irrigation in the greenhouse uses active learning to instill students with more knowledge of irrigation and provide them with practical skills for irrigating efficiently and conservatively in the future.
Planting Technique Matters in Reducing Vinca Disease in Landscapes
Authors: Chen Yan , Bracy Regina , Owings Allen
Published: February 2019

Annual vinca, Catharanthus roseus, is exceptionally adaptive to the summer heat and the sandy loam or clay soil in the southeastern region and provides season-long blooms once established in landscape plantings. A wide variety of colors, sizes, and applications are available for landscape use. However, diseases such as alternaria leaf spot and phytophthora leaf blight are prevalent in this region in vinca plantings. Effective disease control requires frequent fungicide application that is expensive and may pose negative effects on the environment. Proper planting techniques including date of planting, fertilization rate at planting, and variety selection may improve plant growth, reduce disease severity, and save landscape service business labor in disease management. Plants of three varieties: open-pollinated `Cooler Hot Rose', F1 hybrid `Titan Rose', and trailing variety `Mediterranean Lilac' were planted on 1 Apr. or 1 May in landscape plots. Plants were at the same growth stage at the time of planting and were fertilized with Osmocote 14–14–14 (3 months) at 0, 35, 70, or 140 g·m2. Plant growth index indicates that plant growth increased significantly at increasing fertilization rates; however, plant overall quality ratings were not significantly different among fertilized plants. Disease incidence in July suggests that late planting may reduce alternaria leaf spot in open-pollinated and hybrid upright type vinca. Disease severity in August was more pronounced on trailing vinca and more severe when plants were not fertilized or fertilized with the highest fertilization rate. Tissue analysis indicates that trailing vinca `Mediterranean Lilac' may require less fertilization than upright type.
Are Optical Tools Suitable to Manage Phosphate and Potassium Fertigation in Tomato Crops?
Authors: Sambo Paolo , Gianquinto Giorgio , Forte Valente
Published: February 2019

Several experiments on multispectral radiometer showed its suitability in driving nitrogen fertigation in tomato crop. Nir-Green light ratio describes crop nitrogen status well, highlighting element deficiency or excess, which is a great help to farmers in choosing timing and intensity of fertilizer application. The scientific literature reports several studies about nitrogen management only, but not phosphorus and potassium. Because of the advantage obtained with N, it would be desirable to also adapt it to phosphorus and potassium management. For this purpose, a preliminary trial was carried out on the omato cultivar Brigade grown in pots in a greenhouse. Four nutrient solution were supplied. Three were lacking in N, P, or K—the last had all elements needed for a balanced growth. Radiometer readings were taken once a week during the crop cycle, around noon. First results were encouraging. After some data elaboration, it appeared evident that, in some cases, it was possible to set the fertigation treatments apart by only having a look at the single wavelengths measured by the instrument. Through the Nir/green index, used in N management, phosphorus deficiency was identified as well. Potassium trend line was completely different from those of nitrogen and phosphorus, and very similar to that of the control. The utilization of the radiometer in handling potassium fertigation in tomato appeared somewhat difficult. Its application might be desirable, instead, for phosphorus fertigation in addition to nitrogen. The 560 and 710 nm wavelengths might be the especially more useful for this purpose, although a simple index or a combination of some simple indices able to identify phosphorous deficiency/excess and to screen them from those induced by nitrogen are needed.
Recent Developments in Primer Design for DNA Markers in Higher Plants
Authors: Yang Xiaohan , Scheffler Brian E. , Weston Leslie A.
Published: February 2019

Primer design is a critical step in the application of PCR-based technologies in genetic diversity analysis of horticultural plants. As more plant genomes have been sequenced in recent years, the emphasis of primer design strategy has shifted to genome-wide and high-throughput direction. This poster summarizes recent advances in primer design for profiling of DNA polymorphism in higher plants, including new primers for the classical plant DNA marker system such as simple sequence repeat (SSR) and single-nucleotide polymorphism (SNPs), as well as newly developed DNA marker systems such as sequence-related amplified polymorphism (SRAP), sequence-specific amplification polymorphism (SSAP), target region amplification polymorphism (TRAP), and universal rice primer (URP). Although most of these primers were designed for agronomical crops, they could be applied to horticultural plants because plant genomes are evolutionarily related. Also, these new primer design strategies could help horticultural researchers develop better primers specifically for profiling of polymorphism in a variety of horticultural crops, invasive weeds, or medicinal plants. We will present examples of their utilization in these diverse systems.
Intergeneric Hybrids between Weigela and Diervilla (Caprifoliaceae)
Authors: Touchell Darren , Viloria Zenaida , Ranney Thomas
Published: February 2019

Weigela Thunb. consists of 12 species distributed throughout Northeast Asia. Diervilla Mill. is a closely related genus containing three species endemic to North America. Taxa from both of these genera are important nursery crops. Hybrids between these genera could potentially combine the excellent cold hardiness and adaptability of Diervilla with diverse forms, foliage colors, and flower colors found in Weigela. Prior attempts to create intergeneric hybrids between these genera were unsuccessful and resulted in embryo abortion before seeds matured. To overcome this barrier, ovule culture and micropropagation procedures were used to develop intergeneric hybrids. Cleaved amplified polymorphic sequences (CAPS) analysis was used to verify hybrids. Intergeneric crosses, D. lonicera × W. middendorfiana, D. sessilifolia × W. florida (two clones), and D. lonicera × W. florida were attempted. Crosses of D. lonicera × W. middendorfiana did not produce viable hybrids. From the remaining three crosses, a total of 544 plants were obtained from 1278 ovules. About 85% of the 544 plants appeared very chlorotic or had low vigor, and senesced when transferred to multiplication medium. Only 80 of the 544 plants were successfully maintained in tissue culture, of which 10 have been successfully transferred ex vitro. CAPS analysis indicated that a majority of these plants were hybrids. Further studies are focused on improving tissue culture procedures and other methods to develop tetraploids to increase plantlet vigor and fertility.
Spatial Variability of Grape Yield and Quality: Using GIS as a Precision Viticulture Tool to Optimize Vine Yield and Quality
Authors: Ennahli Said , Kadir Sorkel
Published: February 2019

Variability due to soil types, topography, and climate within a vineyard influences grapevine physiological parameters and fruit quality. Technical feasibility of using precision Geographic Information System (GIS) as a viticulture tool to improve vineyard management and increase wine quality will be investigated. The study was conducted in an experimental vineyard where rows consist of plots with 24 cultivars and selections randomly planted and managed similarly. Monitored vineyard parameters collected by Global Positioning System (GPS) location include soil characteristics, soil moisture, vine growth, crop load, and fruit characteristics. Geospatial maps are used to differentiate yield between the cultivars and selections as high, medium, or low. Production was determined from each variety/selection within the vineyard. Yield parameters were number of clusters, cluster weight, and weight of 50 berries; fruit composition (such as pH), titratable acidity, soluble solids concentration, and anthocyanins were measured. Maps for each factor will be derived via GIS tools and spatial analysis will be conducted to assess which spatial variability factor has more effect on grapevine physiology, yield, and fruit quality. This type of analysis can be used by grape growers to achieve specific wine characteristics in a large or small vineyard by controlling all sources of variability, leading to the ability to perform precision viticulture in the future, with low cost.
Physiological Responses of Three Grapevine Cultivars to Partial Root Drying
Authors: Ennahli Said , Kadir Sorkel
Published: February 2019

Partial root-zone drying (PRD) irrigation management has been developed for grapevines as an efficient method to control excessive growth, improve fruit quality, and save water without compromising yield. PRD is based on knowledge of the mechanisms that control transpiration and requires slow dehydration of half of the plant root system, whereas the other half is irrigated. A study was conducted in the field to evaluate the effect of PRD on physiological characteristics, growth, yield, and fruit quality of three grape cultivars. The wetting and drying cycle of the PRD-vine root system is alternated on a 10–14 day schedule. Significant reduction in vigor was observed in treated plants compared with control plants. Root biomass was not affected, but fine roots significantly increased in PRD-treated plants, compared with that of the control. This contributed to the ability of PRD-treated plants to maintain leaf water potential similar to that of the control. Stomatal conductance of PRD plants was significantly reduced when compared with that of the control plants. Abscisic acid (ABA) concentration in leaves of PRD vines increased significantly when compared to the control vines. PRD treatment significantly increased yield and fruit quality when compared with the control treatment. PRD significantly increased water use efficiency (pruning weight per unit of water applied). This study shows that PRD stimulated ABA production in the drying roots, which caused reduction in stomatal conductance and transpiration rate, leading to a substantial reduction in vegetative growth without compromising yield and fruit quality.
A Winter Protection Method for Blackberries
Authors: Takeda Fumiomi , Handley David
Published: February 2019

A combination of simple cultural practices, a modified rotatable crossarm (RCA) trellis system, and covering plants with insulation material in winter overcame the lack of cold hardiness in trailing blackberries that have been established at Kearneysville, W.Va. After tying canes to trellis wires and rotating the cross-arms to below horizontal, tied canes were close to the ground, allowing them to be covered with protective materials, such as floating rowcover and polyethylene plastic during winter. Covers were removed in early spring and the canes remained in the horizontal orientation until bloom, which promoted flowering laterals to grow upright. After bloom, the cross-arm was rotated beyond vertical to position the fruit on one side of the row and improve harvest efficiency. In Jan. and Feb. 2005, the daily minimum temperatures under the FRC+PE covers were about 3 °C higher than in the open. The covers also provided protection against the wind. Tissue damage in protected trailing blackberries was significantly less than for unprotected plants. `Siskiyou' plants in covered plots produced 3 to 5 times more fruit than plants in the open. Harvesting of `Siskiyou' fruit occurred during the red raspberry harvest season or 2 to 3 weeks earlier than for eastern blackberries. Our findings suggest that trailing blackberries can grow satisfactorily and produce fruit if the adverse effect of low temperatures and winds is mitigated with our trellis system and winter protection method. If practical cultural techniques for improving their winter survival become available, there is a potential for early-season high-quality blackberry production in the mid-Atlantic coast region.
Suppression of Flowering in `Bluecrop' Highbush Blueberry
Authors: Black Brent , Ehlenfeldt Mark , Martin Robert
Published: February 2019

Precocious varieties of highbush blueberry may over-crop during the first few seasons in the fruiting field, adversely affecting plant establishment. Reducing or preventing bloom in the nursery and during establishment would be beneficial in preventing early cropping and reducing the risk of infection by pollen-borne viruses. We investigated the efficacy of foliar applications of ProVide® (Valent BioSciences), a commercial GA4+7 formulation, for suppressing flower bud initiation in blueberry. One-year-old rooted cuttings of `Bluecrop' were obtained from a commercial nursery and established in 11-L pots at the Blueberry and Cranberry Research Center, Chatsworth, N.J. Dilute foliar applications of ProVide® were made at concentrations ranging from 50 to 400 mg·L-1 a.i., ranging from 7 July to 1 Sept. 2004, with 10 replicate plants per treatment. Floral and vegetative buds were counted the following spring. A separate experiment was initiated in 2005, with concentrations of 200 and 400 mg·L-1 a.i. applied in August and September. For the 2004 study, the greatest flower bud suppression resulted from repeat applications at 400 mg·L-1 a.i. Weekly applications from 7 July to 1 Sept. resulted in a 70% reduction in flower bud number, whereas three weekly applications from 18 Aug. to 1 Sept. reduced flower bud number by >88%. Neither treatment significantly reduced total bud numbers (vegetative + floral) compared to untreated and water-sprayed controls, indicating that the treatments did not reduce plant growth. Results for the 2005 treatments will also be presented.
(135) Study on the Seed Progeny of Echinacea purpurea Mench.
Authors: Dzhurmanski Anatoli , Varbanova Kana , Zheljazkov Valtcho
Published: February 2019

Common coneflower (Echinacea purpurea) is used as medicinal, cutflower, or ornamental plant. There is significant diversity and chemotypes within the species. Flower morphology and shape has been shown to affect fertilization and, subsequently, seed formation and yields, and seed germination. The aim of this study was to describe morphological and biological characteristics of locally available Echninacea seed progeny and evaluate segregating populations in F1. Overall, the F1 seed progeny of Echinacea purpurea was clustered into three different groups with distinct morphological characteristics and ornamental qualities: 1) plants having tubular type of flowers, 38.9% of all plants; 2) plants with flat flowers; and 3) plants with cone-shaped flowers. The latter is the most commonly found type. We found that 11% of all Echninacea plants would fail to have seed set. However, 55% of Echninacea plants with tubular (spherical) flowers would be without seeds. Of the plants with tubular flowers, 40% were with tubules longer than 10 mm. The plants from the F2 and F3 progenies were with very low seed productivity, with greater variation of morphological characteristics, and some of them with characteristics not found in F1. Several promising forms with potentially high ornamental value were identified.
(5) Cucumber Cultivars and Cultural Practices for Patio Gardening
Authors: Crane Melisa , Wehner Todd
Published: February 2019

Cucumber (Cucumis sativus L.) is one of the most popular vegetables grown in U.S. home gardens. The objectives of this study were to identify suitable cultivars and proper plant density for use with container-grown cucumber. Additional objectives were to determine the value of field trials for predicting cucumber performance in containers, and to evaluate different plant types (dwarf vs. tall, gynoecious vs. monoecious, pickling vs. slicing) for container use. Fourteen cultivars and breeding lines were tested at three densities in two seasons using a randomized complete-block design with six replications. Pickling cucumbers were M 21, M 27, NC-74, `NC-Danbury', `NC-Dixon', `Sumter', `Vlaspik', and `Picklebush'. Slicing cucumbers were `Bush Whopper II', `Spacemaster 80', `Bush Champion', `Marketmore 76', `Dasher II', and `Cherokee 7'. Plant densities were one, two, or three plants per container. For both the spring and summer container trials, there were corresponding field trials run at the same time for comparison. Best performance was obtained using three plants per container, or 4 L of soil volume per plant. There was a strong, significant correlation between patio and field trials, permitting gardeners to choose cucumber cultivars with high yield, high quality, and disease resistance using data from field trials. Pickling-type cucumbers have thinner skin than slicing-type cucumbers that were bred for shipping. Gynoecious types must be planted with monoecious cultivars to assure fruit set. Monoecious types can self-pollinate, and have the additional advantage of longer harvest period. Thus, home gardeners may want dwarf, monoecious, pickling types for best performance in containers. The best cultivar of that type was `NC-Danbury'.
(7) Effect of Leaf Removal on Beef Tomato Cultivated under Greenhouse Conditions
Authors: Macias-Duarte Rubén , Grijalva-Contreras Raul Leonel , Robles-Contreras Fabián , de Jesus Valenzuela-Ruiz Manuel
Published: February 2019

The tomato (Lycopersicon esculentum Mill.) is the most important crop under greenhouse conditions and covers 73% of the area under that system in Mexico. To increase fruit quality and yield, leaf removal is necessary to produce a balance between the vegetative and generative growth of tomato production. The objective of this experiment was to determine the effect of leaf removal on the tomato quality and production under greenhouse conditions. The evaluation was carried out in the Experimental Station INIFAP-CIRNO inside a polyethylene greenhouse. The date of seedling establishment was 28 Sept. 2003. In this trial, we used the Beatrice variety and a plant density of 3.78 plants/m2. We compared four treatments of leaf removal: 1) two leaves below the cluster; 2) two leaves below the cluster and later to remove those leaves when fruit reaches commercial size; 3) severe leaf removal; and 4) the control with no leaf removal. The results show significant differences between the intensively of leaf removal. The highest yield values corresponded to the treatment 2) with a yield of 281 t·ha-1 and fruit weight of 153 g vs. 202 t·ha-1 and 137.7 g of fruit weight for the control treatment.
(184) Phenolic Composition and Antioxidant Activity of Sweetpotato Cultivars Marketed in the European Union
Authors: Padda Malkeet S. , Picha David H.
Published: February 2019

Phenolic compounds and antioxidant activity were quantified in the principal sweetpotato cultivars marketed in the European Union. Total phenolic content, individual phenolic acids, and antioxidant activity in each cultivar were determined using Folin-Denis reagent, reversed-phase HPLC, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods, respectively. Significant differences in phenolic composition and antioxidant activity were found between cultivars. A Jamaican-grown, white-fleshed cultivar had the highest total phenolic content [4.11 mg·g-1 chlorogenic acid (dry tissue weight)], while the highest antioxidant activity [3.60 mg·g-1 Trolox (dry tissue weight)] was observed in the orange-fleshed California-grown cultivar Diane. Chlorogenic acid and 3,5-dicaffeoylquinic acid were the predominant phenolic acids, while caffeic acid was the least abundant in most cultivars. The highest content of chlorogenic acid (0.42 mg·g-1 dry tissue weight); 3,5-dicaffeoylquinic acid (0.43 mg·g-1 dry tissue weight); and 3,4-dicaffeoylquinic acid (0.25 mg·g-1 dry tissue weight) was present in the white-fleshed Jamaican cultivar. The orange-fleshed cultivars Diane and Beauregard had the highest content of caffeic acid (0.13 mg·g-1 dry tissue weight) and 4,5-dicaffeoylquinic acid (0.32 mg·g-1 dry tissue weight), respectively.
(69) Use of Hypochlorous Acid for Treatment of Greenhouse Irrigation Water
Authors: Newman Steven E.
Published: February 2019

Scaling from dissolved and suspended solids in irrigation water reduces the efficiency of greenhouse irrigation systems. Water deposits inside pipes reduce water flow and deposits may reduce the flow through irrigation emitters, often clogging them. If not properly maintained, the clogging of emitters requires constant maintenance. This results in considerable labor expense and/or emitter replacement. Scaling inside irrigation system pipes also has the potential to harbor plant pathogens from the resulting biofilms. Oxcide, a novel hypochlorous acid (HOCl) compound, is produced electrochemically by removing sodium and hydroxide from sodium hypochlorite. The elimination of sodium hydroxide from the product creates a nontoxic oxidizer. A system to inject Oxcide into irrigation water at a commercial Colorado greenhouse was installed to maintain irrigation efficiency of emitters and irrigation lines during Winter 2003. The oxidation reduction potential (ORP) was monitored and visual evaluations of irrigation equipment in the Oxcide treated zones compared to those zones not treated with Oxcide was conducted. During January through March, geranium stock plants were irrigated with water that maintained ORP levels at around 600 mV. Visual ratings of the irrigation emitters revealed that the injection of Oxcide in the irrigation water did reduce the level of deposition. Deposition on the main feed lines was so thick that they hindered the complete closure of existing valves. Treatment of the irrigation water Oxcide injection for six months successfully removed of the scale and deposits from the water line.
(72) Effects of Clay-amended Substrates on Production of Nursery and Greenhouse Crops
Authors: Catanzaro C. , Bhatti S. , Jordan B.T.
Published: February 2019

The U.S. Environmental Protection Agency limits the amount of nitrate and phosphate, yet these nutrients are applied in relatively large amounts during crop production. The objective of greenhouse studies conducted in 2002–05 was to determine the effects of calcined, attapulgite-type clays used as substrate amendments during production of containerized poinsettias, chrysanthemums, and ornamental grasses. Crops were grown with recommended rates of controlled-release fertilizers and irrigation volumes set to achieve a leaching fraction around 0.2. Results with poinsettias grown in substrates amended with clays were as follows: EC of leachate from poinsettia was reduced by up to 39% in the first few weeks after potting; orthophosphate concentration in leachate was reduced by up to 74% in peat-based substrate; cumulative irrigation volume required to produce plants in 16.5-cm containers was reduced by 11%. With two chrysanthemum cultivars, clays reduced EC of leachate and increased plant growth. A non-calcined clay reduced growth of poinsettia and `Oborozuki' Japanese sweetflag grass, but not `Karl Foerster' feather reed grass. Results from these studies suggest that, with controlled irrigation volumes, calcined clays added to a peat-based substrate can reduce leachate nutrient concentrations and reduce crop water requirements without negatively affecting crop growth or quality.
(73) Effect of Media on Growth of Euphorbia pulcherima `White Star'
Authors: Nair Ajay , Zhang Donglin , Burnett Stephanie
Published: February 2019

Euphorbia pulcherima Willd. ex Klotzsch (poinsettia) are grown commercially in all 50 states. This experiment was conducted to find a suitable media for cultivating `White Star' poinsettia under natural day-length conditions in Orono, Maine. The growth, morphology, and foliar and substrate nutrient concentration of `White Star' poinsettia was evaluated in three different media formulations (Promix®, Metromix-560®, and a 1:1 v/v mixture of Promix® and Metromix-560®). Results indicated minimal variability in overall plant height, but there were significant differences in the canopy area. Canopy area was greatest for plants grown in Promix® followed by a combination of Promix® and Metromix-560®. Plants grown in Promix® recorded the highest fresh weight (170.6 g). Bract area was statistically insignificant among the three treatments. Nutrient status of the media varied widely and was significant for nitrate–nitrogen, phosphorus, soluble salts, iron, calcium, magnesium, manganese, sodium, sulfur, and zinc. Foliar analysis revealed that nutrient concentrations also significantly differed across treatment media. Optimum media pH for growing poinsettia ranges from 6.0 to 7.5. Media pH for Promix® was 5.9, which was significantly higher than Metromix-560® (4.65) and Promix® + Metromix-560® (1:1 v/v; 5.3). In spite of significant differences in foliar and substrate nutrient concentrations, overall plant growth remained the same.
(90) Young Tree Growth and Leaf Function of Citrus Seedlings under Colored Shade Netting
Authors: Li Kuo-Tan , Syvertsen Jim
Published: February 2019

Young citrus trees and seedlings in Florida's commercial nurseries are often grown under shade cloth netting to avoid high light and temperature. To investigate the potential benefit of altering radiation by colored shade nets, `Cleopatra' mandarin (Cleo, C. reticulata Blanco) seedlings and potted `Valencia' trees [Citrus sinensis (L.) Osbeck] on Cleo or Carrizo [Carr, C. sinensis × Poncirus trifoliate (L.) Raf.] rootstocks were grown in full sun or under 50% shade from blue, black, silver, grey, and red colored shade nets. Changes in photosynthetically active radiation (PAR) and temperatures under the shade were monitored. Leaf function and leaf chlorophyll contents were measured, and plants were harvested by the end of the experiment for shoot and root growth measurements. Plants under the shade received an average of 45% PAR and had lower mid-day leaf temperature than plants in full sun. Plants under blue nets had greatest leaf chlorophyll a, b, and total chlorophyll content, whereas those under red nets had the lowest. However, shading improved photosystem II efficiency from measurements of leaf chlorophyll fluorescence (Fv/Fm) regardless of the color of shade nets. Shading increased shoot growth, shoot to root ratio, and total plant dry weight of Cleo seedlings, especially those under silver nets.
(301) Bioavailability of Dairy Manure Compost Nutrients to Urban Landscape Plants
Authors: Sloan John , McKenney Cynthia , McAfee James , Mackay Wayne
Published: February 2019

Dairy manure compost (DMC) may be an effective soil amendment when establishing new urban landscapes. The objective of this study was to evaluate the bioavailability of DMC nutrients to typical urban landscape plants. In March 2003, DMC rates of 0, 9, 18, and 27 kg/m2 (0, 1.25, 2.5, 5 cm) were incorporated into the top 10 to 15 cm of Austin silty clay soil. Half of each 6 x 6-m plot was established with bermudagrass sod and the other half with six types of ornamental plants consisting of annual, perennial, and woody species. During the third 2005 growing season, plant tissue was harvested from selected landscape plants to measure biomass production and nutrient uptake. Plant growth and nutrient contents were compared to plant available soil nutrients that were measured during fall 2004 and 2005. Plant available P in the upper 7.5 cm of soil ranged from 89 to 170 mg/kg in September 2004 and from 31.3 to 105.5 mg/kg in August 2004. Potassium and trace elements (Fe, Cu, and Zn) were also increased in the upper 7.5 cm by DMC applications. Increased concentrations of plant available soil nutrients in DMC-amended plots were correlated to overall increases in plant growth and nutrient uptake. Bermuda grass exhibited increased growth and increased tissue concentrations of N, P, K, and Zn. Penta biomass and nutrient uptake were also increased by DMC applications. Lantana stem weights significantly increased with DMC application rate up to 18 kg/m2, but no additional increases were obtained with the 27 kg/m2 rate. Results of this study show that, after three growing seasons with no additional fertilization, a 1- to 2-cm application of dairy manure compost is sufficient to provide continued fertility to landscape plants.
(36) Evaluating an Agroforestry Approach to Woody Cuts Production in Florida
Authors: Thetford Mack , Jose Shibu , Fletcher Edward H.
Published: February 2019

The demand for special forest products used in the floral industry has a rapidly expanding market. Woody cuts come from perennial shrubs, trees, or woody vines, and are used as floral design materials for the flowering branches, foliage, fruits, or stems. Evaluation of specialty and woody cut production is needed to determine if these plants may be adapted to sustainable agroforestry production systems. An agroforestry approach to woody cuts production for longleaf pine (Pinus palustris) producers in Florida is a natural approach given the relatively open canopy of this timber species and the occurrence of several native species with ornamental characteristics that are currently utilized on a small scale for woody cuts production. The present approach to evaluating the suitability of these systems utilizes the following objectives: 1) Evaluate the production potential of ornamental species in monoculture and agroforestry silviculture systems and determine the biophysical interactions between system components. This objective will assess system design and its role on system productivity; determine time to ornamental yield. 2) Quantify the cost of establishing ornamentals for woody cuts production in both monoculture and agroforestry systems. This objective will identify and track overhead/fixed costs and variable costs associated with the ornamental cuts and timber crops for monoculture and agroforestry production systems over a 3-year period. 3) Investigate potential markets for the distribution and sale of cut foliage, flowers or stems. This objective will lead to consultations with florists and cut foliage wholesalers about potential market volume, price, and specifications for products produced within the longleaf pine agroforestry production system.
(268) Lutein Content in Sweetpotato Leaves
Authors: Cavalier Michael , Kachatryan Armen , Menelaou Evodokia , Losso Jack , LaBonte Don
Published: February 2019

Fresh leaves of six sweetpotato [Ipomoea batatas (L.) Lam.] genotypes, `Beauregard', `Bienville', L 99-35, L 00-8, L 01-145, and L 01-29 were characterized for lutein. Lutein is a carotenoid capable of delaying blindness-related macular degeneration. The content of lutein in sweetpotato ranged from 0.38 to 0.58 mg·g-1 fresh weight. Beta-carotene separated from lutein on HPLC chromatograms, and, when spiked in pure lutein extract, did not interfere with lutein separation. Stems were also characterized and found not to contain lutein. Our results showed that sweetpotato leaves are an excellent source of dietary lutein and surpass levels found in leafy crucifers. Leaves of sweetpotato and a related species are used as human food in some countries and could be a source of extracted lutein for commercial purposes.
(269) Black Pigmentation in Capsicum—A Biochemical and Molecular Account
Authors: Lightbourn Gordon J. , Griesbach Robert J. , Stommel John R.
Published: February 2019

Color observed in plants is due to several pigments, in particular chlorophylls, carotenoids, flavonoids, and betalains. The many hues can be attributed to a number of biochemical factors, inclusive of pigment concentration, pigment combinations and their ratios, and vacuolar pH. Shades of violet to black pigmentation in pepper (Capsicum annuum L.) are attributed to anthocyanin accumulation. The color of unripe pepper fruit varies from green and yellow to ivory, through varying shades of violet and purple to nearly black. Whereas pepper fruit color is important for culinary product quality, foliar pigmentation is also an important aspect of ornamental variety appeal. Foliage and stem color may vary from green to varying shades of green/purple to nearly black. HPLC analysis of violet and black pepper fruit revealed a single anthocyanidin that was identified as delphinidin. Black fruit contained five-fold higher chlorophyll concentrations in comparison to violet fruit, which contained relatively little chlorophyll. Differences in fruit pH were not statistically significant. Similar to fruit, black pepper leaf tissue contained delphinidin as the predominant anthocyanidin, but in higher concentration relative to that found in fruit. The results demonstrate that high concentrations of delphinidin in combination with chlorophyll account for black pigmentation. Real-time PCR analysis of tissues that varied in pigmentation intensity due to varying anthocyanin concentration revealed functional, but differentially expressed, structural genes in the anthocyanin biosynthetic pathway. Analysis of regulatory gene expression identified a MYB transcription factor that was differentially expressed in response to varying anthocyanin concentration.
(270) Screeing for Melonworm Resistance in Squash and Pumpkins
Authors: Pérez-Arocho Jorge , Wessel-Beaver Linda
Published: February 2019

Melonworm (Diaphania hyalinata) is one of the most damaging pests of squash and pumpkin (Cucurbita sp.) in tropical/subtropical regions of the Americas. In order to identify sources of resistence to melonworm, we evaluated 345 accessions of C. moschata, including both tropical and temperate types, originating from the Americas, Europe, Asia, and Africa. C. argyrosperma (65 accessions) was also evaluated. Accessions were field tested in five single-plant complete blocks planted over a 9-month period in Isabela, P.R. Each plant was evaluated for foliar damage (0–4 scale) at 3 and 6 weeks. Larval counts were made on a five-leaf sample at 8 weeks. Accessions were classified for degree of leaf mottling and pubescence. Differences among accessions were found for foliar damage and number of larva, but ranking of accessions varied, depending on the criteria used to measure resistance. In order to establish independent culling levels, we considered the lower 30% of accessions for each trait. The upper limit was ≤0.42 for foliar damage at 3 weeks, ≤0.50 damage at 6 weeks, and ≤1.25larva/plant. This led to the selection of 34 resistant accessions. We used a similar technique to identify the most susceptible accessions. The susceptible accessions will be used as a control group when the 34 selections are further evaluated. Within C. moschata, accessions with either green leaves or less pubescence had less leaf damage and fewer larva than accessions with mottled leaves or more pubescence. As a group, C. argryosperma accessions were more susceptible, and nearly all had mottled leaves and little pubescence. Untested accessions with green leaves and/or little pubescence might yield additional sources of resistance to melonworm.
(271) Ornamental Characteristics of Lesquerella (Lesquerella sp.) Plants
Authors: Jenderek Maria M.
Published: February 2019

Lesquerella (Brassicaceae) seeds contain high concentrations of hydroxyl fatty acids with long carbon chains, similar to imported castor oil. Although species within the genus are considered as an alternative oil crop, lesquerella plants have ornamental characteristics that may present a valuable landscape alternative for dry open spaces. Seeds of certain Lesquerella species are already a component of wild flower seed mixtures sold commercially. The purpose of this study was to describe ornamental aspects of selected accessions in the USDA Lesquerella germplasm collection maintained at the National Arid Land Plant Genetic Resources Unit. From 2003 to 2005, more than 140 accessions from 30 species were characterized for selected plant characteristics. The majority of lesquerella flowers were yellow, but some species, such as L. mcvaughiana, L. mexicana, L. ovalifolia, L. pallida, L. perforata, and L. stoniensis, had white flowers. Petal length ranged from 4 to 11 mm, and the number of flowers per an unbranched stem was from two to seven. While the duration of full bloom of many lesquerella plants was between 15 to 40 days, the full bloom of plants of 10 accessions lasted from 50 (PARL 166, L. argyrea; W6 20836, L. grandiflora; W6 20841, L. lasiocarpa) to 72 days (PI 596362, L. fendleri). Those traits make the plants suitable for planting in landscape borders, low hedges, or color patches. The main use of the USDA, NPGS Lesquerella germplasm collection (201 accessions) is in cultivar development of a new oil crop. However when considering the duration of bloom and the abundance of flowers, several accessions may be used as ornamental crops, especially in semi-arid and arid landscapes where water supply is limited.
(93) Vegetative and Flower Bud Development, and Fruit Set of Low-chill Peach Cultivars in North-central, Central, and Southwest Florida
Authors: Wert Todd , Williamson Jeffrey G. , Rouse Robert E.
Published: February 2019

Four low-chill peach cultivars were evaluated at three locations in Florida for vegetative and reproductive bud development and fruit set. Twenty trees (five each of `Flordaprince', `Tropicbeauty', `UFgold', and `Flordaglo') were planted at each site in Feb. 2002. Prior to budbreak in Spring 2004 and 2005, three shoots per tree of average length and diameter were selected at a height between 1.5–2.0 m and the numbers of vegetative and flower buds per node were recorded for each shoot. No consistent pattern for the number of vegetative buds per node was observed among cultivars and locations, or across years. However, 'Tropicbeauty' tended to have fewer vegetative buds per node than `Flordaprince' during both seasons, although not at all locations. Overall, the number of flower buds per node was greater for north-central Florida than for central or southwest Florida. There were no consistent tends over years and among locations for the ranked order of flower buds per node by cultivar. The percentage of nodes without flower or vegetative buds (blind nodes) was generally greatest for `Tropicbeauty' at most locations during both years. During 2005, the percentage of blind nodes was greater in central and southwest Florida than in north-central Florida. Overall, fruit set was similar between the central and north-central Florida locations. Fruit set tended to be higher for `UFGold' and `Flordaglo' than for `Flordaprince' or `Tropicbeauty'.