bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement of High-throughput Genotype Analysis After Implementation of a Dual-curve Sybr Green I-based Quantification and Normalization Procedure
Authors: Livingstone Donald , Freeman Barbie , Tondo Cecile L. , Cariaga Kathleen A. , Oleas Nora H. , Meerow Alan W. , Schnell Raymond J. , Kuhn David N.
Published: February 2019

The ability to rapidly genotype a large number of individuals is the key to any successful marker-assisted plant breeding program. One of the primary bottlenecks in high-throughput screening is the preparation of DNA samples, particularly the quantification and normalization of samples for downstream processing. A rapid and simple Sybr Green I-based quantification procedure that can be performed in a 96-well format is outlined. In this procedure, a dual standard curve method is used to allow better resolution of dilute samples and to reduce fluorescence value variation between samplings. A method to quickly normalize samples, and the importance of normalization, is also explored. We demonstrate that successful fragment amplification of a Theobroma grandiflorum (Willd ex Spreng) Schum. population is increased from 70% to 98% when each DNA extract is quantified and normalized as opposed to quantifying only a subset and normalizing all the samples based on the average of that subset. Improved microsatellite amplification was also observed among individuals in the monocot genus Phaedranassa Herb. ssp. Additionally, when our normalization method is applied to a Persea americana Mill. population, 97% of the samples normalized to 4 ng·μL−1 amplify at least three of six microsatellite regions, whereas only 30% of the samples below 4 ng·μL−1 (i.e., samples that could not be normalized) amplify at least three regions. We describe an undemanding method to quantify and normalize a large number of samples, which can be done manually or can be automated.
Biomass Distribution in Kalanchoe blossfeldiana Transformed with rol-genes of Agrobacterium rhizogenes
Authors: Christensen Brian , Sriskandarajah Sridevy , Müller Renate
Published: February 2019

Kalanchoe blossfeldiana transformed with Agrobacterium rhizogenes exhibited marked alterations in morphology and biomass distribution. Plants termed root-inducing (Ri) lines were regenerated from hairy roots produced by inoculating leaf explants with Agrobacterium rhizogenes wild-type strain ATCC15834. Six Ri lines were characterized in a greenhouse trial and all Ri lines had reduced dry weights of main shoot, lateral shoots, leaves, and flowers compared with control plants. The reduction in dry weights of these organs correlated with reduced plant height, shoot length, leaf area, and number of flowers per plant. Furthermore, an altered distribution of dry matter was evident in the Ri plants, where the greater part of dry matter was allocated into leaves and secondly into flowers, whereas the majority of dry matter in control plants was allocated into flowers and secondly into leaves. Furthermore, a higher percentage of dry matter was allocated into the main shoot of the Ri lines in comparison with that of control plants. Increased dry matter in leaves and in the main shoot in the Ri lines appeared to be at the expense of dry matter allocated into flowers. Moreover, an increased number of vegetative lateral shoots was recorded in the Ri lines, whereas the number of reproductive lateral shoots was decreased. Possible mechanisms behind the altered resource distribution are discussed.
Phenotypic Characteristics of Ten Garlic Cultivars Grown at Different North American Locations
Authors: Volk Gayle M. , Stern David
Published: February 2019

Garlic (Allium sativum L.) cultivars grown under diverse conditions have highly elastic environmental responses, particularly relating to skin color and yield. Ten diverse garlic cultivars were grown at 12 locations in the United States and Canada for 2 consecutive years to identify the environmentally responsive phenotypic traits of garlic. Clove arrangement, number of topsets, topset size, topset color, number of cloves, clove weight, clove skin color, and clove skin tightness were generally stable for each cultivar regardless of production location and conditions. Scape presence varied with cultivar and location, but for the most part, cultivars classified as hardneck types produced scapes and those classified as softnecks did not produce scapes. Bulbs grown at the northern Colorado, Minnesota, Pennsylvania, Vermont, and Washington locations were generally larger than the other locations. Soil potassium levels were positively correlated with bulb circumference and fresh weight. Soil sulfur and manganese levels were correlated with bulb sulfur and manganese content. Bulb wrapper color and intensity were highly dependent on location and cultivar. The Silverwhite cultivar was consistently white and ‘Ajo Rojo’, ‘German White’, ‘Inchelium’, ‘Sakura’, and ‘Spanish Roja’ were generally white with some faint violet or brown stripes or splotches across the locations. In contrast, cultivars Chesnok Red, Purple Glazer, Red Janice, and Siberian were more likely to have moderate or dark violet stripes, streaks, or splotches, particularly when grown at the northern Colorado, Minnesota, Nevada, New York, Ontario, Pennsylvania, or Washington locations. These results can help farmers identify niche regional markets that provide novel products to consumers. From these results, it was shown that garlic cultivars or classes grown under diverse conditions have highly elastic soil nutrient responses, particularly relating to skin color and yield.
Importance of Genotype on Carotenoid and Chlorophyll Levels in Broccoli Heads
Authors: Farnham Mark W. , Kopsell Dean A.
Published: February 2019

Carotenoids are secondary plant metabolites in vegetables known to be essential in the human diet and reported to confer various positive health-promoting effects when consumed. Brassica oleracea L. vegetables like kale, cabbage, and broccoli are recognized as excellent sources of dietary carotenoids. Broccoli has emerged as the most important B. oleracea crop in the United States and it likely supplies more carotenoids to the U.S. diet than the other crops of this species. However, very little is known about the general carotenoid profile of this important vegetable or the levels of specific carotenoids and how they might vary among genotypes. Thus, the objectives of this study were to assess carotenoid profiles of different inbred broccoli heads; to assess chlorophyll concentrations measured simultaneously during carotenoid assays; to determine the relative effects of genotype versus environment in influencing head carotenoid levels; and to examine phenotypic correlations between carotenoid levels and other traits. Results show lutein to be the most abundant carotenoid in broccoli heads ranging from 65.3 to 139.6 μg·g−1 dry mass (DM) among nine inbreds tested in three environments. Genotype had a highly significant effect on lutein levels in broccoli heads and the ratio of σ2
g/σ2
p for this carotenoid was 0.84. Violaxanthin also exhibited a significant genotype effect, but it was found at lower levels (17.9 to 35.4 μg·g−1 DM) than lutein. β-carotene and neoxanthin were detected at levels similar to violaxanthin, but genotypic differences were not detected when all environments were compared. This was also true for antheraxanthin, which was detectable in all genotypes at lower levels (mean of 13.3 μg·g−1 DM) than the other carotenoids. Significant genotypic differences were observed for both chlorophyll a and b among the studied inbreds; however, no environment or genotype-by-environment effects were observed with these compounds. Results indicated that most carotenoids measured were positively and significantly correlated with one another, indicating that higher levels of one carotenoid were typically associated with higher levels of others. This study emphasizes the relative importance of lutein in broccoli heads and the key role that genotype plays with this compound, ultimately indicating that breeding cultivars with increased levels of this particular carotenoid may be feasible.
Effect of Nitrogen, Location, and Harvesting Stage on Peppermint Productivity, Oil Content, and Oil Composition
Authors: Zheljazkov Valtcho D. , Cerven Vasile , Cantrell Charles L. , Ebelhar Wayne M. , Horgan Thomas
Published: February 2019

Peppermint (Mentha ×piperita) is currently not a common crop in the southeastern United States. Recently, there has been an interest in peppermint as an essential oil crop for this region. In 2007, a field experiment was conducted in Mississippi to determine the effect of nitrogen (N) (0 and 80 kg·ha−1), location (Verona and Stoneville), and harvesting stage (bud formation and flowering) on peppermint productivity, oil content, and composition. Peppermint biomass yields were higher at Verona (8.12 t·ha−1) than at Stoneville (6.12 t·ha−1). However, the essential oil content was higher at Stoneville (1.1%) than at Verona (0.6%). Generally, N rate at 80 kg·ha−1 did not affect oil yield and composition compared with 0 kg·ha−1. The concentrations of the major essential oil constituents were: (-)-menthol at 26% to 30%, (-)-menthone at 14% to 21%, (+)-menthofuran at 5% to 11%, and eucalyptol at 3% to 4% of total essential oil (wt/wt) and were generally within the values previously reported. The concentrations of (-)-menthone and (+)-menthofuran were significantly higher at Stoneville, 21% and 11%, respectively, than at Verona (14% and 6%). The (-)-menthol, (-)-menthone, and (+)-menthofuran yields/ha were higher at Stoneville than at Verona. Overall oil content and yields were higher at bud formation than at flowering, 1.3 and 1.8 times, respectively. In addition, the concentration of (-)-menthone and eucalyptol and the yields of (-)-menthone, (+)-menthofuran, and eucalyptol were higher at bud formation than at flowering. The results from this study demonstrated peppermint can be successfully grown in Mississippi and provide essential oil yields and composition comparable to those in the northwestern United States, the traditional peppermint-growing region.
Effects of Temperature and the Combination of Liquid Lime Sulfur and Fish Oil on Pollen Germination, Pollen Tube Growth, and Fruit Set in Apples
Authors: Yoder Keith , Yuan Rongcai , Combs Leon , Byers Ross , McFerson Jim , Schmidt Tory
Published: February 2019

Effects of temperature and the combination of liquid lime sulfur (LLS) and fish oil (FO) applied during bloom on pollen germination and pollen tube growth in flowers and fruit set were examined in apples (Malus ×domestica Borkh.). Percent germination of pollen of ‘Manchurian’ crabapples and ‘Golden Delicious’ apple flowers on the stigmatic surface of ‘Golden Delicious’ pistils increased with increasing temperature from 13 to 29 °C in the first 24 and 48 h after pollination, respectively, but not thereafter. Pollen tube growth rate in the style increased quadratically with increasing temperature from 13 to 29 °C. ‘Manchurian’ was a more effective pollenizer of ‘Golden Delicious’ than was ‘Golden Delicious’ pollen. For example, at 24 or 29 °C, some ‘Manchurian’ pollen tubes grew to the base of ‘Golden Delicious’ styles by 24 h after pollination. On the other hand, no ‘Golden Delicious’ pollen tube grew to the base of a ‘Golden Delicious’ style regardless of temperature and time. Pollen tube growth rate in the style increased with increasing day/night temperature from 7/0 to 24/7 °C. The time required for pollen tubes to grow to the base of styles decreased with increasing day/night temperature from 13/2 to 24/7 °C. Only ≈36 h was required for pollen tubes to grow to the base of style at 24/7 °C, whereas pollen tubes grew very slowly and no pollen tubes grew to the base of style at 7/0 °C regardless of pollen source. LLS + FO, applied 4 or 24 h after pollination, inhibited pollen germination, pollen tube growth in the style, fertilization, and fruit set, but it had no effect when applied 48 h after pollination. These results suggest that LLS + FO applied at this bloom stage causes flower or fruit abscission most likely by inhibiting pollen germination, pollen tube growth in the style, and fertilization.
Canopy Photosynthesis and Time-of-day Application of Supplemental Light
Authors: Markvart Jakob , Rosenqvist Eva , Sørensen Helle , Ottosen Carl-Otto , Aaslyng Jesper M.
Published: February 2019

There is increasing use of electricity for supplemental lighting in the northern European greenhouse industry. One reason for this may be to secure a high growth rate during low-light periods by an attempt to increase net photosynthesis. We wanted to clarify which period of the day resulted in the best use of a 5-h supplemental light period for photosynthesis and growth. The periods tested were supplemental light during the night, day, morning, and evening. The experiments were carried out in daylight climate chambers measuring canopy gas exchange. The air temperature was 25 °C and the CO2 level ≈900 ppm. Vegetative chrysanthemum was used, because this species responds quickly to change in light level. The leaf areas of the plant canopies were nondestructively measured each week during the 4-week experimental period. The fact that the quantum yield of photosynthesis is greater at low than at high light intensities favors the use of supplemental light during the dark period, but growth measured as dry weight of the treated plants at the end of the experiments was not significantly different given identical light integrals of the treatments. However, one experiment indicated that increased time with dark hours during day and night (24 h) might decrease net photosynthesis. The assimilation per unit leaf area was approximately the same during times of sunlight through a diffusing screen at 100 μmol·m−2·s−1 of photosynthetic photon flux (PPF) as during times of supplemental (direct) light application at PPF of 200 μmol·m−2·s−1 by high-pressure sodium lamps. We conclude that during the winter and periods of low light intensities, the daily carbon gain does not depend on the time of supplemental light application, but is linked to the total light integral. However, extended time with dark hours during day and night (24 h) might be a disadvantage because of longer periods with dark respiration and subsequent loss of carbon. Our results indicate that during times of low light conditions, it is not necessary to include factors such as the timing of supplemental lighting application to achieve higher net photosynthesis in climate control strategies.
Effects of Light Intensity and Paclobutrazol on Growth and Interior Performance of Pachira aquatica Aubl.
Authors: Li Qiansheng , Deng Min , Chen Jianjun , Henny Richard J.
Published: February 2019

Pachira aquatica Aubl. has recently been introduced as an ornamental foliage plant and is widely used for interiorscaping. Its growth and use under low light conditions, however, have two problems: leaf abscission and accelerated internode elongation. This study was undertaken to determine if production light intensity and foliar application of paclobutrazol [β-(4-chlorophenyl)methyl-α-(1,1-dimethylethyl)-1H- 1,2,4- triazole-1-ethanol] improved plant growth and subsequent interior performance. Two-year-old P. aquatica trunks were planted in 15-cm diameter plastic pots using a peat-based medium and were grown in a shaded greenhouse under three daily maximum photosynthetic photon flux densities (PPFD) of 285, 350, and 550 μmol·m−2·s−1. Plant canopy heights, average widths, and internode lengths were recorded monthly over a 1-year production period. Two months after planting, the plant canopy was sprayed once with paclobutrazol solutions at concentrations of 0, 50, and 150 mg·L−1, ≈15 mL per plant. Before the plants were placed indoors under a PPFD of 18 μmol·m−2·s−1 for 6 months, net photosynthetic rates, quantum yield, and light saturation and compensation points were determined. Results showed that lowering production light levels did not significantly affect canopy height, width, or internode length but affected the photosynthetic light response curve and reduced the light compensation point. Foliar application of paclobutrazol reduced internode length, thereby resulting in plants with reduced canopy height and width and more compact growth form. Paclobutrazol application also reduced the light compensation point of plants grown under 550 μmol·m−2·s−1. Plants with the compact growth form did not grow substantially, dropped fewer leaflets, and thus maintained their aesthetic appearance after placement indoors for 6 months. These results indicated that the ornamental value and interior performance of P. aquatica plants can be significantly improved by producing them under a PPFD range between 285 and 350 μmol·m−2·s−1 and foliar spraying of paclobutrazol once at a concentration between 50 and 150 mg·L−1.
Variation in Development and Response to Root-zone pH Among Seedlings of Dirca palustris (Thymelaeaceae) from Three Provenances
Authors: Peterson Bryan J. , Graves William R.
Published: February 2019

Horticulturists have not promoted use of Dirca palustris L. (eastern leatherwood) despite its suite of traits valued by gardeners and landscapers. Horticultural production of D. palustris may be hindered by slow shoot growth and sensitivity of plants to edaphic conditions. Because of discrepancies in reported tolerances of D. palustris to root-zone pH, we assessed whether pH of soils supporting indigenous populations in Florida, Maine, and North Dakota corresponded to responses of seedlings from the three provenances to root-zone pH of 4.5 to 7.3 in soilless media. Regression showed that root zones at pH 5.8 promoted maximum stem length of seedlings from Florida and North Dakota, whereas root zones at pH 4.5 led to maximum stem length of seedlings from Maine. Root-zone pH 5.6 and 5.5 fostered maximum root and shoot dry weight, respectively, for seedlings from Florida, whereas root zones at pH 4.5 promoted maximum root and shoot dry weights of seedlings from Maine and North Dakota. Averaged over provenance, relative leaf greenness decreased by 62%, and foliar nitrogen, iron, manganese, and zinc decreased by 49%, 70%, 95%, and 48%, respectively, as root-zone pH increased from 4.5 to 7.3. Foliar phosphorus decreased at both low and high pH. The pH of soils where seeds were collected did not predict optimal root-zone pH for stem length or biomass accrual in soilless media; genotypes from soils with a pH of 7.4 in North Dakota did not exhibit greater tolerance to high pH than genotypes from Maine or Florida, where pH of indigenous soil was 6.1 and 5.2, respectively. Averaged over pH treatments, seedlings from Florida showed the greatest stem length and formed the most shoot biomass, whereas seedlings from North Dakota had stouter stems, greater root biomass, and greater root-to-shoot ratios than did seedlings from Florida and Maine. Our results illustrate that acidic media facilitate horticultural production of D. palustris, that further evaluation of provenance differences could facilitate selection of genotypes for horticulture, and that tolerances of genotypes to root-zone pH do not strictly correspond to the pH of soils on which they were indigenous.
Seed Preconditioning with Natural and Synthetic Antioxidants Induces Drought Tolerance in Tomato Seedlings
Authors: MacDonald Mason T. , Lada Rajasekaran R. , Robinson A. Robin , Hoyle Jeff
Published: February 2019

There is strong evidence that Ambiol® (a derivative of 5-hydroxybenzimazole) promotes drought tolerance in many plants; it is often suggested that this is the result of its antioxidant properties. Recent evidence has also shown that several natural antioxidants promote carrot germination under drought stress. Thus, it was hypothesized that seed preconditioning using natural antioxidants might confer drought tolerance. Ambiol®, ascorbic acid, β-carotene, lutein, and lycopene were chosen as antioxidants at concentrations of 0.1 mg·L−1, 1.0 mg·L−1, and 10 mg·L−1. A preconditioning treatment was applied by soaking tomato (Solanum lycopersicum L.) seeds in an antioxidant solution for 24 h. Of the antioxidants tested, 10 mg·L−1 Ambiol®, 1.0 mg·L−1 β-carotene, 1.0 mg·L−1 ascorbic acid, and 0.1 mg·L−1 lycopene were shown to increase shoot dry mass by 114%, 94%, 56%, and 83%, respectively, in droughted seedlings when compared with a droughted control. Similar benefits were observed in root dry mass, leaf area, photosynthesis, and water use efficiency. Proteins were extracted from the seeds of certain treatments, before and after germination, and separated using isoelectric focusing. Specific proteins were found to be induced through all preconditioning treatments, whereas Ambiol® and β-carotene were found to induce specific proteins, independent of those induced through imbibition, both before and after germination. This result suggests that Ambiol® and β-carotene evoke specific proteins that may confer drought tolerance to the key physiological processes studied. In addition, protein profiles of ascorbic acid, β-carotene, and Ambiol® after germination had fewer visible bands than the controls, suggesting an accelerated mobilization or conversion of proteins within the seed.
Effects of Root and Foliar Applications of 24-Epibrassinolide on Fusarium Wilt and Antioxidant Metabolism in Cucumber Roots
Authors: Ding Ju , Shi Kai , Zhou Yan-Hong , Yu Jing-Quan
Published: February 2019

Root and foliar applications of 24-epibrassinolide (EBL), an immobile phytohormone with antistress activity, were evaluated for their effects on reducing fusarium wilt and their influence on antioxidant and phenolic metabolism in roots of cucumber plants (Cucumis sativus L. cv. Jinyan No. 4). EBL pretreatment significantly reduced disease severity together with improved plant growth and reduced losses in biomass regardless of application methods. EBL treatments significantly reduced pathogen-induced accumulation of reactive oxygen species (ROS), flavonoids, and phenolic compounds, activities of defense-related and ROS-scavenging enzymes. The enzymes included superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, catalase as well as phenylalanine ammonia-lyase and polyphenoloxidase. There was no apparent difference between two application methods used. EBL applications triggered a slight increase in H2O2 concentration followed by increases in the transcript levels of WRKY transcription factor and defense-related genes. This study demonstrated that EBL enhanced resistance to fusarium wilt by a novel mechanism that was not related to its active transport or increase in antioxidant system.
Water Deficit Stress Responses of Three Native Australian Ornamental Herbaceous Wildflower Species for Water-wise Landscapes
Authors: Kjelgren Roger , Wang Lixue , Joyce Daryl
Published: February 2019

Perennial wildflower species are important but not well-understood elements in water-wise landscaping that anchors urban water conservation programs in arid climates. Comparative growth and physiological responses to soil substrate drying of three herbaceous Australian ornamental species from habitats of variable moisture regimes were investigated in the context of isohydric and anisohydric behavior. Clonal Orthosiphon aristatus, Dianella revoluta ‘Breeze’, and Ptilotus nobilis plants were container-grown individually and competitively together in two separate studies. In both studies, plants were water-stressed through cyclical dry downs. We measured stomatal conductance (g
S), soil water content, and water potential during each study and osmotic adjustment estimated from pressure-volume data and plant biomass at the end of each study. O. aristatus, a rainforest species, fit a general anisohydric model of high water use and more negative water potential during soil drying until stomatal closure and leaf wilting. D. revolata and P. nobilis, indigenous to Australia's dry interior, fit a general isohydric, drought-tolerant model of stomatal closure from water deficits that moderates leaf water potential but through different mechanisms. P. nobilis and D. revolata moderate water use and maintain acceptable aesthetic performance under water stress, suitable for mixed low-water landscape plantings. O. aristatus would not be suitable for low-water urban landscapes, either isolated or in mixed plantings, because of high soil water depletion and wilting.
Attractiveness of Parboiled Rice Hulls to the Fungus Gnat, Bradysia sp. nr coprophila (Diptera: Sciaridae), Adult Relative to Standard Growing Medium Components
Authors: Cloyd Raymond A. , Marley Karen A. , Larson Richard A. , Arieli Bari
Published: February 2019

This study was conducted to assess the attractiveness of growing media containing parboiled rice hulls (PBH) to fungus gnat, Bradysia sp. nr. coprophila (Diptera: Sciaridae), adults. In comparing commercially prepared PBH with peatmoss (LC1) and pine bark (SB200)-based growing media, it was established that the fungus gnat adults were not specifically attracted to any of the growing media, even those containing PBH, with the mean proportion of fungus gnat adults recovered in the sample compartments ranging from 0.16 to 0.23. Moisture content was more important in terms of fungus gnat adult attractiveness to the growing media. In addition, the volatile constituents of the various growing media were determined using a steam distillation procedure. The component that was present in the highest concentration (39.2%) in the dried PBH as determined by gas chromatography analysis was palmitic acid, a straight-chain C16 fatty acid. S8 (cyclo-octasulfur), a well-known odoriferous component of degraded waste materials, was present at a higher concentration (6.2%) in the RH1 growing medium (80% peatmoss) compared with the other growing media evaluated. The data indicate that PBH, when incorporated in certain growing media, do not attract fungus gnat adults, and as such, greenhouse producers can use PBH as an amendment to growing medium without having to be concerned with the prospect of luring fungus gnat adults and sustaining plant damage.
Germination Responses of Purpletop and Big Bluestem Caryopses Subjected to Distilled Water or Potassium Nitrate Prechilling, Sodium Hypochlorite, and Storage
Authors: Olszewski Michael W. , Folin Grant J.
Published: February 2019

Purpletop [Tridens flavus (L.) Hitchc.] and big bluestem (Andropogon gerardii Vitman) are incorporated into native grass seed mixes for use in ecological restoration. Alleviation of low seed vigor and poor stand establishment would benefit the restoration process by increasing the animal habitat in restored zones. This study determined the effectiveness of prechilling with distilled water (dH2O) versus potassium nitrate (KNO3), sodium hypochlorite (NaOCl) treatments, and short-term storage conditions on seed germination, seedling growth, and stand establishment of purpletop and big bluestem. Prechilling of ‘Niagara, NY Ecotype’ big bluestem for 7 days at 5 °C in dH2O increased final germination percentage (FGP) and germination rate provided caryopses were not dried before sowing. Optimal FGP, germination rate, and germination synchrony were obtained for ‘VA Ecotype’ purpletop after prechilling for 14 days at 5 °C in dH2O without subsequent caryopsis drying or at 0.2% KNO3 with or without subsequent caryopsis drying. Prechilling increased germination synchrony for purpletop but not for big bluestem. NaOCl treatments did not enhance germination or seedling vigor of purpletop or big bluestem. Using nonstored, prechilled caryopses resulted in greater root lengths than stored caryopses or nontreated controls, although optimal purpletop growth required that they be sowed moist, whereas optimal big bluestem growth required that they be dried-back before sowing. In greenhouse experiments, higher seeding rates were correlated with increased number of seedlings for nontreated or prechilled big bluestem and for prechilled purpletop, but not for nontreated purpletop, which had poor stand establishment at all seeding rates. The results indicate that prechilling of caryopses before incorporation into a warm-season grass seed mix increased seedling establishment of purpletop but not big bluestem.
Effects of Irrigation Frequency during Establishment on Growth of Ilex cornuta ‘Burfordii Nana’ and Pittosporum tobira ‘Variegata’
Authors: Wiese Christine L. , Shober Amy L. , Gilman Edward F. , Paz Maria , Moore Kimberly A. , Scheiber Sloane M. , Brennan Meghan M. , Vyapari Sudeep
Published: February 2019

Irrigation for establishing landscape plants is restricted to the first 60 days after planting by most water management districts in Florida, yet woody plants may require between 6 and 12 months to become established. Survival and growth of shrubs planted into landscapes depend on adequate irrigation until shrubs develop a root system capable of compensating for evapotranspiration losses. This study examined the effect of irrigation frequency on survival, quality, and growth of Ilex cornuta Lindl. & Paxt. ‘Burfordii Nana’ and Pittosporum tobira [Dryand] ‘Variegata’ planted in north (Citra, FL; USDA hardiness zone 8b) and central (Balm, FL; USDA hardiness zone 9b) Florida. Shrubs were planted into the landscape from 11.4-L (#3) containers at 3-month intervals for a total of eight planting dates over 2 years and irrigated every 2, 4, or 8 days with 3 L of water at each irrigation event. Scheduled irrigation was discontinued once roots grew to the canopy edge [12 to 22 weeks after planting (WAP)] and survival, quality, and growth were evaluated from that point through 104 WAP. Ilex cornuta ‘Burfordii Nana’ irrigated every 2 days had greater canopy growth index (52 through 88 WAP), canopy dry mass (52 and 104 WAP), and maximum root spread (20 through 64 and 88 WAP) when compared with shrubs irrigated every 8d in hardiness zone 8b. Pittosporum tobira ‘Variegata’ irrigated every 2 days had greater canopy growth index (12 through 104 WAP), maximum root spread (20 through 28 and 64 through 88 WAP), and canopy dry mass (52 and 104 WAP) when compared with shrubs irrigated every 8 days in hardiness zone 8b. However, there were no differences in shoot or root growth resulting from irrigation frequency for these shrubs planted in hardiness zone 9a. Irrigation frequency did not affect shrub survival or aesthetic quality at either location. Although more frequent irrigation (every 2 days) resulted in greater plant growth in zone 8b, the two shrub species tested survived and grew after planting in hardiness zones 8b and 9a on natural rainfall alone provided they were irrigated during establishment with 3 L every 4 to 8 days until roots reached the canopy edge. Subsequent supplemental irrigation was only needed in the following 18 months when plants showed visible signs of drought stress, which occurred when there was no measurable rainfall for 30 consecutive days.
Somatic Embryogenesis in Hedychium bousigonianum
Authors: Sakhanokho Hamidou F. , Rajasekaran Kanniah , Kelley Rowena Y.
Published: February 2019

An efficient primary somatic embryo (SE) and secondary somatic embryo (SSE) production system was developed for the ornamental ginger Hedychium bousigonianum Pierre ex Gagnepain. Addition of two ethylene inhibitors, salicylic acid (SA) and silver nitrate (AgNO3), to the culture media improved the system. Callus was initiated and proliferated on a medium containing Murashige and Skoog (MS) basal salts supplemented with 9.05 μM 2,4-dichlorophenoxyacetic acid and 4.6 μM kinetin. Friable callus was transferred to a liquid medium containing MS basal salts, B5 vitamins, 0.6 μM thidiazuron, and 8.9 μM 6-benzylaminopurine to induce somatic embryogenesis. The effects of various concentrations of SA (0, 25, 50, 75, 100, 125, 150 μM) and AgNO3 (0, 10, 20, 30, 40, 50, 60 μM) on callus growth, SE, and SSE development was further evaluated. The rate of callus growth decreased as the concentrations of SA or AgNO3 increased. AgNO3 and SA at all concentrations stimulated SE and SSE development better than the control although a decrease in embryo production was observed at higher concentrations of both SA and AgNO3. The best concentrations for SA were 75 and 100 μM, whereas for AgNO3, they were 30 to 50 μM for both SE and SSE production.
Influence of Daily Light Period and Irradiance on Yield and Leaf Elemental Concentration of Hydroponically Grown Sweetpotato
Authors: Mortley Desmond G. , Burrell Stephanie , Bonsi Conrad K. , Hill Walter A. , Morris Carlton E.
Published: February 2019

Growth chamber experiments were conducted to evaluate the effect of irradiance and daily light period on storage root yield and leaf elemental concentration of two sweetpotato cultivars grown hydroponically by use of the nutrient film technique (NFT). Stem cuttings (15 cm) of cv. Whatley/Loretan and Georgia Jet were grown in NFT channels (0.15 × 0.15 × 1.2 m) in reach-in growth chambers under light period/irradiance combinations of 18 h: 300 μmol·m−2·s−1 or 9 h: 600 μmol·m−2·s−1 photosynthetic photon flux. Temperature was 28/22 °C light/dark with a relative humidity of 70% ± 5%. Storage root and foliage yields were greater in both cultivars exposed to a longer daily light period and lower irradiance. The main effect of cultivar indicated that storage root yield was significantly greater among plants of ‘Whatley/Loretan’ compared with that of ‘Georgia Jet’, whereas foliage yield was similar between cultivars. Leaves of plants grown under longer daily light period and lower irradiance had significantly lower concentrations of all elements, nitrogen, phosphorus, potassium, calcium, magnesium, manganese, iron, calcium, boron, and zinc, except for calcium, manganese, and boron. There were no significant differences in leaf elemental concentration between cultivars. Thus, a longer daily light and lower irradiance enhanced biomass production of sweetpotato but reduced leaf elemental concentration probably because of a “dilution” effect.
Incidence of Multiple and Distinct Species of Caulimoviruses in Dahlia (Dahlia variabilis)
Authors: Eid Sahar , Druffel Keri L. , Saar Dayle E. , Pappu Hanu R.
Published: February 2019

Dahlia mosaic is a serious disease affecting dahlias. In addition to the Dahlia mosaic virus (DMV) reported previously, we characterized two putative new caulimoviruses, tentatively designated as DMV-D10 and Dahlia common mosaic virus (DCMV), from dahlia. To better understand their relative incidence in dahlia, a total of 213 samples were collected during 2007 and 2008 from several varieties of cultivated dahlia (D. variabilis) in the United States. Samples were tested for the three caulimoviruses using virus-specific primers in a polymerase chain reaction. Amplicons were cloned and sequenced to confirm the infection of dahlia with these viruses. Results showed that DMV-D10 was the most prevalent (94%) followed by DCMV (48.5%) and DMV (23%). Mixed infections were common and viruses were detected irrespective of symptom expression at the time of sampling. Two percent of the samples were not infected by any of the three tested caulimoviruses. Results suggest that caulimovirus infections are widespread in dahlia and highlight the need for testing and production of virus-free material to reduce their spread.
Maternal Lineages of the Cultivated Strawberry, Fragaria ×ananassa, Revealed by Chloroplast DNA Variation
Authors: Honjo Masanori , Kataoka Sono , Yui Susumu , Morishita Masami , Kunihisa Miyuki , Yano Takayoshi , Hamano Megumi , Yamazaki Hiromichi
Published: February 2019

We analyzed sequence variation in chloroplast DNA (cpDNA) to investigate the origin of the cultivated strawberry, Fragaria ×ananassa. From analysis of two noncoding regions, trnL–trnF and trnR–rrn5, we found three haplotypes (V, C, and X) in F. ×ananassa. Haplotype V corresponded to the haplotype of F. virginiana and was possessed by cultivars bred over a wide geographic range, including North America, Europe, and Japan. Almost all the North American cultivars analyzed in this study possessed haplotype V, suggesting a founder effect. Haplotype C corresponded to the haplotype of F. chiloensis and was detected mainly in Japanese cultivars. Haplotype X was found in only two English cultivars. This haplotype was positioned as intermediate between haplotypes V and C in a median-joining network and was considered to be representative of the process of differentiation between F. virginiana and F. chiloensis. Results of controlled crosses indicate that cpDNA haplotypes of F. ×ananassa are maternally inherited. These results verify that F. ×ananassa is an interspecific hybrid between F. virginiana and F. chiloensis and indicate that traditional cultivars of F. ×ananassa have been derived from at least three maternal lineages. We demonstrate that the cpDNA variation detected in this study can be used to verify parentage and for extending hypotheses about June yellows, a leaf variegation disorder in strawberry.
Characterization of Calcium and Boron Deficiency and the Effects of Temporal Disruption of Calcium and Boron Supply on Pansy, Petunia, and Gerbera Plugs
Authors: Krug Brian A. , Whipker Brian E. , Frantz Jonathan , McCall Ingram
Published: February 2019

Pansy (Viola ×wittrockiana Gams.), petunia (Petunia ×hybrida hort. Vilm.), and gerbera daisy (Gerbera jamesonii Bol. ex Adlam.) plants were grown hydroponically to characterize the deficiency symptoms caused by the absence of calcium (Ca) or boron (B). Primary symptoms occurred on the youngest tissue for both elements, but distinct differences between Ca and B deficiencies were observed. Plants responding to Ca deficiency exhibited discoloration and upward rolling of leaves and ultimately necrosis. Plants responding to B deficiency exhibited minor chlorosis, upward curling, and thickening of leaves, distorted meristems, and strap-like leaves. A second experiment investigated how a temporary disruption of Ca or B affects the plant throughout the crop cycle. Either Ca or B was removed from the nutrient solution for a 7-day period from Day 15 to Day 21, Day 22 to Day 28, or Day 29 to Day 35 after sowing. After the 7-day disruption, the respective element was reintroduced to the plants. Regardless of when the plants were deprived of Ca or B, the symptoms of the respective deficiency were present at the end of the experiment. These studies have shown that a temporary disruption of either Ca or B can cause lasting symptoms throughout the plug production cycle. Also, the symptoms that have been observed in plug production were most similar to those symptoms caused by B deficiency, not Ca deficiency.
Genetic Diversity and Population Structure of Traditional Greek and Cypriot Melon Cultigens (Cucumis melo L.) Based on Simple Sequence Repeat Variability
Authors: Tzitzikas Emmanouil N. , Monforte Antonio J. , Fatihi Abdelhak , Kypriotakis Zacharias , Iacovides Tefkros A. , Ioannides Ioannis M. , Kalaitzis Panagiotis
Published: February 2019

Seventeen simple sequence repeat (SSR) markers were used to assess the genetic diversity and population structure among traditional Greek and Cypriot melon cultigens (Cucumis melo L.). All SSR markers were polymorphic with a total number of 81 alleles, whereas all cultigens could be distinguished with at least one SSR, except cultigens 43 and 41. Reference accessions showed larger genetic variability with an average of four alleles per locus and 0.65 gene of diversity compared with an average of 2.47 alleles per locus and 0.30 of gene diversity for the Greek/Cypriot cultigens. Observed heterozygosity was very low, indicating a lack of outcrossing, at least in recent times. Unrooted neighbor-joining tree analysis and population structure analysis clustered the cultigens and the reference genotypes into five groups. All cultigens could be distinguished; the Cypriot cultigens were more closely related to the inodorus ‘Piel de Sapo’, whereas the Greek cultigens were located in an intermediate position between the inodorus ‘Piel de Sapo’ and the cantalupensis ‘Védrantais’. The cultigen ‘Kokkini’ was the most divergent among the Greek and Cypriot cultigens. This association between geographic origin and genetic similarity among Greek and Cypriot cultigens indicates geographic isolation. Most of the cultivars from the same cultivar group (i.e., inodorus, cantalupensis) clustered together, but some exceptions were found, suggesting that former inodorus landraces would have been transformed to cantalupensis as a result of intercrossing and further selection by farmers. Results of population structure analysis support mixing between cantalupensis and inodorus. ‘Agiou Basileiou’, an inodorus cultigen, was assigned to the subpopulation IV/II of which II is a pure cantalupensis subpopulation. Greek and Cypriot melon cultigens were developed from a broader germplasm base than western Mediterranean cultivars and exhibited useful for melon breeding programs genetic variability.
Comparative Analysis of Antioxidant Properties and Fruit Quality Attributes of Organically and Conventionally Grown Melons (Cucumis melo L.)
Authors: Salandanan Karen , Bunning Marisa , Stonaker Frank , Külen Oktay , Kendall Patricia , Stushnoff Cecil
Published: February 2019

Antioxidant properties and quality attributes were evaluated for 10 melon (Cucumis melo L.) cultivars grown under conventional and certified organic conditions in a 2-year field study. Differences among cultivars, produced either by conventional or organic methods, contributed the largest sources of variation in antioxidant properties. A 2.1- to 2.2-fold difference was seen between groups of cultivars with the highest and lowest levels of ascorbic acid when produced by organic and conventional methods, respectively. Choice of cultivar using conventional and organic production, respectively, enabled a 1.7- and 1.6-fold gain in total phenolics, a 2.6- and 4.2-fold gain in radical scavenging capacity determined by 2, 2′-azinobis (3-ethylbenzthiazoline-6-sulfonic acid), and a 1.8- and 2.4-fold gain determined by the 2,2-diphenyl-1-picrylhydrazyl assay. Based on an antioxidant index, cultivars with the highest antioxidant properties were Savor, Sweetie #6, Early Queen, Edonis, and Rayan. Organic melons had significantly higher ascorbic acid over both years, whereas total phenolics content was higher only in the first year. Percent dry matter and soluble solids content also varied widely among cultivars but were unaffected by production system. Choice of cultivar provides a viable option for growers interested in producing melons with high antioxidant properties. Cultivars with high antioxidant levels may provide a competitive marketing and supply niche for producers, but the full extent of diversity for antioxidant attributes requires further evaluation of cultivars and germplasm.
Evaluating Fertilization and Water Practices to Minimize NO3-N Leachate from Container-grown Forsythia
Authors: Alam Mohammed Z. , Chong Calvin , Llewellyn Jennifer , Lumis Glen P.
Published: February 2019

To minimize fertilizer and water use, and NO3-N runoff from container culture, growth, and nutrient status of forsythia (Forsythia ×intermedia Zab. ‘Spring Glory’) in No. 2 containers were compared in response to a controlled-release fertilizer (CRF; Nutricote 18-6-8 100-day at rates of 2, 4, and 6 kg·m−3) and placements (incorporation and topdress) under three irrigation strategies [drip-irrigated low (25% or less) leaching fraction (DrLoLF), hand-sprinkled low leaching fraction (HsLoLF), and hand-sprinkled high (50% or less) leaching fraction (HsHiLF)]. In a coexperiment under drip irrigation only, forsythia response was also examined under incorporation, topdress, and dibble fertilizer placements with the same CRF rates applied as single or split dose. Dibble fertilizer placement was superior to both incorporation and topdress in this order. Maximum growth of forsythia occurred at rates of 4.7 kg·m−3 with dibble. With incorporation and topdress, maximum growth was not achieved even at the 6 kg·m−3 maximum rate tested. Forsythia grew better with incorporated than with topdressed CRF with the DrLoLF treatment. The response was reverse with HsHiLF or showed no differences with HsLoLF. Under drip irrigation, greater concentrations of NO3-N generally leached from incorporation and dibbled containers in this order than from topdress. Less nitrate was leached from the topdressed containers because less was released from the CRF prills. At the 6 kg·m−3 CRF rate, total cumulative NO3-N leachings were 76, 85, and 22 kg·ha−1 (45 × 45-cm container spacing) for dibbling, incorporation, and topdress, respectively, under drip irrigation. Split application of CRF greatly reduced NO3-N in leachate, although plant growth also was reduced as a result of less availability of and uptake of nutrients under this strategy.
Seed Production and Viability of Eight Porterweed Selections Grown in Northern and Southern Florida
Authors: Wilson Sandra B. , Knox Gary W. , Muller Keona L. , Freyre Rosanna , Deng Zhanao
Published: February 2019

Nettleleaf porterweed (Stachytarpheta cayennensis) is a potentially invasive ornamental plant in Florida. Plant growth, visual quality, flowering, and seed viability were assessed for nettleleaf porterweed and eight closely related alternatives planted in northern and southern Florida. In northern Florida, ‘Mario Pollsa’ porterweed (Stachytarpheta spp.), ‘Violacea’ porterweed (Stachytarpheta mutabilis), ‘Naples Lilac’ porterweed (Stachytarpheta spp.), ‘Red Compact’ porterweed (Stachytarpheta speciosa), and nettleleaf porterweed (Stachytarpheta cayennensis) achieved high flower ratings between 4 (average to good flowering) and 5 (abundant flowering, peak bloom) during 4 or more months. Also, jamaican porterweed (Stachytarpheta jamaicensis), ‘Violacea’ porterweed, ‘Red Compact’ porterweed, and nettleleaf porterweed achieved visual quality ratings between 4 and 5 (good to excellent quality) throughout most of the study. In southern Florida, the same cultivars received high flower ratings but generally for shorter periods of time. Also, ‘Violacea’ porterweed and ‘Red Compact’ porterweed consistently received visual quality ratings that were above 4 (good quality, very desirable). During the course of the 28-week study, nettleleaf porterweed produced the greatest number of spiked inflorescences with 39% to 80% seed viability. At both locations, ‘Violacea’ porterweed did not produce any viable seed and seed viability was less than 10% for ‘Mario Pollsa’ porterweed, coral porterweed (Stachytarpheta mutabilis), and ‘Naples Lilac’ porterweed.
Decrease in Nitrate Concentration in Leafy Vegetables Under a Solid-state Illuminator
Authors: Samuolienė Giedrė , Urbonavičiūtė Akvilė , Duchovskis Pavelas , Bliznikas Zenonas , Vitta Pranciškus , Žukauskas Artūras
Published: February 2019

We report on a substantial reduction of nitrate concentration in leafy vegetables that were subjected to short-term preharvest treatment by narrow-bandwidth red light of high photosynthetic photon flux density generated by a solid-state illuminator. Lettuce (Lactuca sativa cv. Grand rapids), marjoram (Majorana hortensis, Moench.), and green onions (Allium cepa, L. cv. Lietuvos didieji) were grown to harvest time within a greenhouse under daylight with supplementary lighting provided by standard high-pressure sodium lamps (130 μmol·m−2·s−1). A subsequent 3-day treatment within a phytotron under 638-nm light-emitting diodes (500 μmol·m−2·s−1) resulted in the reduction of nitrate concentration by 44% to 65%. The reduction of nitrates was accompanied by an increased concentration of nutritionally valuable carbohydrates, which is also in line with stimulation of expression of nitrate reductase by photosynthetic metabolites. Another indicator of nutritional quality, the content of vitamin C, exhibited some variation that was not directly correlated with the nitrate reduction rate that may be attributed to carbohydrate content variation and leaf tissue aging.