bluuebunny/crossref_metadata_2025 huggingface dataset:
The Photoperiod-regulated Bud Formation of Red Pitaya (Hylocereus sp.)
Authors: Jiang Yi-Lu , Liao Yuan-Yin , Lin Tzong-Shyan , Lee Ching-Lung , Yen Chung-Ruey , Yang Wen-Ju
Published: February 2019

Red pitaya (Hylocereus sp.), which flowers between May and October and sprouts between November and May in Taiwan, has been confirmed to be a long-day plant. The areoles on the old shoots may be induced to flower after the March equinox naturally, and the floral bud formation occurs in two to three waves from May to October. We conducted experiments on photoperiodic regulation of floral bud formation from June to Dec. 2009 and tested the feasibility of off-season production in 2011. Shortening summer daylength to 8 h inhibited the areoles at the distal end of the shoots to develop into floral buds and promoted sprouting at the proximal ends of the shoots. Night-breaking treatment between the September equinox and the winter solstice led to floral bud formation. The critical daylength seemed to be ≈12 h, and night-breaking treatment would be applicable between the September and the next March equinoxes to produce off-season crops. The duration of night-breaking required for flower differentiation was longer in the cooler than in the warmer season. Four weeks of night-breaking treatment was sufficient to promote flowering in late fall (mid-October to mid-November), but 3 months were required to generate similar result in the winter and early spring (January to March) in southern Taiwan.
Strip Tillage and Compost Influence Carrot Quality, Yield, and Net Returns
Authors: Brainard Daniel C. , Noyes D. Corey
Published: February 2019

Management practices that build soil organic matter—including reduced tillage, cover cropping, and compost applications—may be useful for protecting vulnerable crops from extreme weather events, reducing energy costs, and suppressing pests in carrot (Daucus carota subsp. sativa) production systems. The primary objective of this research was to assess the effects of strip tillage, compost, and carrot cultivar on carrot quality, yield, and profitability. An important secondary objective was to evaluate the impact of tillage and compost on establishment of important weeds in carrot systems—including two species that have developed resistance to linuron: Powell amaranth (Amaranthus powellii) and common purslane (Portulaca oleracea). Field experiments were conducted in 2009 and 2010 comparing conventional tillage (CT) to strip tillage (ST) under two rates of mature compost addition (0 or 3 dry t·ha−1) for three processing carrot varieties (‘Canada’, ‘Finley’, and ‘Recoleta’). In the ST system, a pre-established barley cover crop was left to grow as a windbreak between crop rows until carrots were established. Partial budget analysis was used to estimate net returns associated with all treatments. Compared with CT, the ST system resulted in 1) either equivalent or greater (2010, Finley cultivar) total carrot yields and net returns; and 2) either equivalent or lower summer annual weed densities. Addition of compost resulted in equivalent (2010) or higher (2009) carrot yields and gross returns but did not affect net returns as a result of the increased costs associated with compost application. Compost reduced the density of common purslane in 2009 but resulted in a threefold increase in the density of Powell amaranth in 2010. Our results demonstrate that both ST and compost applications are potentially valuable tools for improving the profitability of carrot production systems. Future research examining the mechanistic basis for compost and tillage effects on carrots and weeds as well as the long-term effects of these practices on profitability of rotational crops would be helpful for optimizing their use in vegetable production systems.
Using Cultural Practices and Cultivar Resistance to Manage Phytophthora Crown Rot on Summer Squash
Authors: Meyer Michael D. , Hausbeck Mary K.
Published: February 2019

The effects of bed height, mulches, composted poultry litter, and cultivars on Phytophthora crown rot, caused by Phytophthora capsici Leonian, of summer squash (Cucurbita pepo L.) were evaluated in the absence of fungicide applications. The experimental design was a split-split-split plot arrangement of a randomized complete block. Bed height (flat or raised) was the main plot treatment. Mulches (bare soil, wheat straw, or plastic) were subplot treatments. Composted poultry litter applications (0 or 4.5 t·ha−1) were sub-subplot treatments. Squash cultivars (Cougar or Payroll) were sub-sub-subplot treatments. Incidence of plant death (%) was assessed from 0 to 35 days post-inoculation (dpi) with P. capsici. Plant death 35 dpi and area under the disease progress curve (AUDPC)differed significantly (P < 0.0001) between the cultivars Cougar and Payroll. Mean plant death 35 dpi was 87% for ‘Payroll’ and 99% for ‘Cougar’. The bed height × cultivar interaction was also significant (P = 0.0018) in the analyses of variance for plant death and AUDPC. Plant death at 35 dpi and AUDPC for ‘Payroll’ were greater in flat beds than raised beds. Disease was unaffected by the main effects of bed height, mulch type, or application of poultry litter. Thirty-two summer squash cultivars and 10 germplasm accessions were also evaluated for resistance to Phytophthora crown rot in a separate greenhouse trial. Crown rot severity was rated on a 1 (no symptoms) to 5 (plant death) scale at 18 dpi. Crown rot severity differed significantly (P < 0.0001) among cultivars and germplasm accessions. Crown rot severity averaged 4.3 on commercial cultivars and 2.2 on germplasm accessions. Crown rot was least severe on the commercial cultivar Spineless Beauty (mean rating = 2.9). No disease developed on four accessions of Cucurbita moschata previously reported to be crown rot-resistant.
Benzyladenine Increases Branching but Reduces Root Growth of Herbaceous Perennial Liners
Authors: Grossman Mara , Freeborn John , Scoggins Holly , Latimer Joyce
Published: February 2019

The objective of this study is to evaluate the branching effect of benzyladenine (BA) on herbaceous perennial plants during the production of rooted cuttings (liners) and to examine and quantify the root growth of these liners using multiple methods of root evaluation. Five crops were studied: Agastache Clayt. Ex Gronov. ‘Purple Haze’, Gaura lindheimeri Engelm. & A. Gray ‘Siskiyou Pink’, Lavandula ×intermedia Emeric ex Loisel. ‘Provence’, Leucanthemum ×superbum (Bergmans ex J.W. Ingram) Bergmans ex Kent. ‘Snowcap’, and Salvia ×sylvestris L. (pro sp.) ‘May Night’. After rooting but before transplant, BA was applied to rooted cuttings as four treatments: controls (0 mg·L−1), one application of 300 mg·L−1, two applications of 300 mg·L−1, or one application of 600 mg·L−1. Results varied by crop; all crops except Salvia had increased branching as measured as either increased lateral or basal branches and/or increased leaders at 3 to 4 weeks after initial treatment. Four crops showed reduced root growth, whereas Gaura was unaffected. Root dry weight was found to be highly correlated with root surface area and root volume. After transplant and growing out, branching of the finished plants was increased in Gaura and Lavandula, unaffected in Salvia and Leucanthemum, and decreased in Agastache. Treating rooted cuttings with BA before transplant increased branching but the effects were not long lasting, which suggests that additional applications at or after transplant may improve finished plant quality. Reductions in root growth noted in rooted cuttings did not affect the growth of finished plants. Chemical names: N-(phenylmethyl)-1H-purine-6-amine (benzyladenine, BA).
Quality of Gamma Ray-irradiated Iceberg Lettuce and Treatments to Minimize Irradiation-induced Disorders
Authors: Fan Xuetong , Sokorai Kimberly J. , Niemira Brendan A. , Mills Robert S. , Zhen Mark Yueqian
Published: February 2019

Irradiation of Iceberg lettuce was recently approved by the U.S. Food and Drug Administration (FDA) to enhance microbial safety and to extend shelf life at doses up to 4 kGy. However, the radiation tolerance of whole head lettuce is unclear. The present study was conducted to investigate the effects of gamma irradiation on the quality of Iceberg lettuce and explore means to reduce irradiation-induced disorders. Irradiation (0.5 and 1.0 kGy) induced symptoms similar to russet spotting and other discolorations (pink ribs, rusty brown, and vein browning) in both external and internal leaves during post-irradiation storage in air at 4 °C. Irradiation in the absence of oxygen or pretreatment with 1 ppm 1-methylcyclopropene had little effect on the irradiation-induced tissue discoloration. However, low oxygen atmosphere when maintained during the entire 14-day storage almost eliminated the disorders. Compared with non-treated control, irradiation created significantly lower headspace O2 and higher CO2 levels in the packages, indicating that irradiation promoted respiration. Our results suggest that modified atmosphere (MA) packaging could be used to mitigate irradiation-induced disorders in Iceberg lettuce.
Influence of Oxygen and Temperature on the Respiration Rate of Fresh-cut Cantaloupe and Implications for Modified Atmosphere Packaging
Authors: Gomes M. Helena , Beaudry Randolph M. , Almeida Domingos P.F.
Published: February 2019

The respiratory behavior of fresh-cut melon under modified atmosphere packaging at various temperatures was characterized to assess the potential for shelf life extension through low-oxygen and to generate information for the development of appropriate packaging conditions. Cantaloupe melon (Cucumis melo var. cantalupensis ‘Olympic Gold’) cubes were packaged and stored at 0, 5, 10, and 15 °C. Packages attained gas equilibrium after 5 days at 10 °C, 6 days at 5 °C, and 10 days at 0 °C. In cubes stored at 15 °C, decay started before steady-state gas levels were reached. Respiration rates were measured and respiratory quotient calculated once steady-state O2 and CO2 partial pressures were achieved inside the packages. O2 uptake increased with temperature and O2 partial pressure (pO2 pkg), according to a Michaelis-Menten kinetics described by = [( × pO2 pkg)/( + pO2 pkg)]. Respiratory parameters were modeled as an exponential function of temperature: = {[1.34 × 10−17 × e(0.131 × T) × pO2 pkg]/[1.15 × 10−24 × e(0.193 × T) + pO2 pkg]} (R2 = 0.95), Q10 = 3.7, and Ea = 84 kJ·mol−1. A good fit to the experimental data was also obtained considering as constant: RO2 = {[4.36 × 10−14 × e(0.102 × T) × pO2 pkg]/[0.358 + pO2 pkg]} (R2 = 0.93), Q10 = 2.8, and Ea = 66 kJ·mol−1. These results provide fundamental information to predict package permeability and steady-state pO2 pkg required to prevent anaerobic conditions and maximize shelf life of fresh-cut cantaloupe. The kinetics of respiration as a function of pO2 suggests that no significant reductions in respiration rate of fresh-cut cantaloupe can be achieved by lowering O2 levels.
Defining Irrigation Set Points Based on Substrate Properties for Variable Irrigation and Constant Matric Potential Devices in Greenhouse Tomato
Authors: Lemay Isabelle , Caron Jean , Dorais Martine , Pepin Steeve
Published: February 2019

Ongoing research on organic growing media for greenhouse tomato production is driven by the constant changes in the quality, stability, and form of the organic byproducts used in the manufacturing of these media. This study was undertaken to determine appropriate irrigation set points for a sawdust–peat mix (SP) under development given that the performance of this substrate appeared to be strongly dependent on appropriate irrigation management. A greenhouse tomato experiment was conducted to compare different irrigation management approaches for a SP substrate in the spring and summer. Using preliminary measurements from an initial experiment (Expt. 1), different irrigation strategies for the SP substrate were compared in a second experiment (Expt. 2): 1) a variable irrigation regime using a timer control (with frequency adjusted as a function of irradiance); 2) tensiometer control at –1.5 kPa; and 3) two constant substrate water potential devices: –1.1 kPa and –0.9 kPa. An irrigation timer/controller using solar radiation input was used with a rockwool control (RC) substrate. Measurements of plant activity [photosynthesis rate and stomatal conductance (gS)], substrate physical and chemical properties, biomass, and yield were obtained. For all irrigation strategies, results indicated that 10% to 20% higher photosynthesis rates and gS values were obtained with the SP substrate compared with RC. Data indicated that moderate drying conditions (matric potential ranging from –2.2 kPa to –1.5 kPa in Expt. 1 and Expt. 2, respectively) relative to container capacity (–0.6 kPa) were beneficial for improving plant photosynthetic activity and allowed the highest yields for the SP substrate. Variable irrigation management showed higher levels of plant activity than constant watering and increased the oxygen concentration in the substrate by ≈2% in absolute value relative to the constant water potential device. Lower CO2 and N2O levels were also observed with the variable irrigation strategy. On the other hand, maximum nutrient solution savings were achieved with the constant matric potential devices (8% to 31% relative to the RC). This study showed high productivity potential for the SP substrate with suitable irrigation management. Replacing conventional growing media with organic waste-based products using an appropriate irrigation strategy may help to increase the sustainability of the greenhouse industry.
Decay Kinetics of Toluene Phytoremediation Stimulation
Authors: Kim Kwang Jin , Yoo Eun Ha , Kays Stanley J.
Published: February 2019

Begonia maculata, Ardisia crenata, and Ardisia japonica plants exposed to 3.5 ppm toluene in air for 12 h displayed a pronounced stimulation (358%, 318%, and 252%, respectively) in subsequent toluene removal potential. The duration of the stimulation effect, monitored over 3 weeks, was short-lived decaying to prestimulation levels within 1 to 7 days depending on species. Elevated phytoremediation rate was dependent on the continued presence of toluene. The rapid rate of increase in phytoremediation and subsequent decay points toward a response mediated by changes in gene expression by the plant, microorganisms within the media, or both rather than an alteration in microbe population. A better understanding of the stimulation response may facilitate the use of plants for indoor air remediation in homes and offices.
Diversity of Genome Size and Ty1-copia in Epimedium Species Used for Traditional Chinese Medicines
Authors: Chen Jianjun , Li Lijia , Wang Ying
Published: February 2019

Epimedium species are traditional Chinese medicinal plants as well as potential groundcover and ornamental plants. In this study, genome size and genome structures of Epimedium species were investigated using flow cytometric and fluorescence in situ hybridization (FISH). The nuclear DNA content of Epimedium species ranged from 8.42 pg/2C (8230.7 Mbp) to 9.97 pg/2C (9752.8 Mbp). The pairwise nucleotide diversity (π) of the fragments of the genes for reverse transcriptase (rt) of Ty1-copia retrotransposon within a species of rt fragments ranged from 0.251 to 0.428 in 10 Epimedium species. Phylogenetic analysis of the sequences revealed four major clades with the largest subclade containing 72 sequences of relatively low nucleotide diversity. FISH indicated that Ty1-copia retrotransposons are distributed unevenly along the pachytene chromosomes of E. wushanense and E. sagittatum, mostly associated with the pericentromeric and terminal heterochromatin. The relatively low sequence heterogeneity of Ty1-copia rt sequences implies that the Epimedium genomes have experienced a few relatively large-scale proliferation events of copia elements, which could be one of the major forces resulting in the large genome size of Epimedium species.
Breeding and Evaluating for Landscape Performance and Fruitlessness in Mexican Petunia (Ruellia, Acanthaceae)
Authors: Freyre Rosanna , Moseley Adam , Wilson Sandra B. , Knox Gary W.
Published: February 2019

Mexican petunia (Ruellia simplex Wright) is a non-native plant that was introduced to Florida sometime in the 1940s and since then has naturalized in most of the state and in other southern states. Since 2007, we have developed at the University of Florida/Institute for Food and Agricultural Science in Gainesville the first Ruellia L. breeding program aiming to develop fruitless plants with different flower colors and growth habits that will not be invasive by seed dispersal. A combination of polyploidization and hybridization methods was used. In 2011, a total of 15 plants were selected and grown in southeastern, north–central, and northwestern Florida (Fort Pierce, Citra, and Quincy) using a randomized block design with three blocks and three plants per plot at each site. Plants were evaluated monthly for landscape performance, flowering, and fruiting. Two hybrids (R10-102 and R10-108) had outstanding potential as new fruitless cultivars for the plant industry having improved landscape performance and flowering.
CO2 Balance of a Commercial Closed System with Artificial Lighting for Producing Lettuce Plants
Authors: Li Ming , Kozai Toyoki , Ohyama Katsumi , Shimamura Shigeharu , Gonda Kaori , Sekiyama Tetsuo
Published: February 2019

The CO2 balance of a commercial closed system with artificial lighting (CSAL), in which lettuce plants (Lactuca sativa L. ‘Early Impulse’, ‘King Crown’, and ‘Cos Lettuce’) were produced every day and CO2 was added to the air by gas cylinders and workers’ respiration, was analyzed. In the experiment, 95% of the CO2 supplied from cylinders was apparently assimilated by the lettuce plants in the commercial CSAL, suggesting that the supplied CO2 was used efficiently. The amounts of CO2 assimilated by the lettuce plants and loss resulting from leakage, respectively, accounted for 78% and 22% of the total amount of CO2 supplied. The amounts of CO2 supplied by the cylinders and by the workers’ respiration, respectively, accounted for 83% and 17% of the total amount of CO2 supplied. Based on the analysis, a relatively high CO2 utilization efficiency of 78% was observed in the experiment despite the operation rate of 33%, which is defined as the percentage of the culture beds with plants. If the operation rate could be increased to 100%, the CO2 utilization efficiency would reach 92%. These results showed that CO2 supplied by the workers’ respiration helped to reduce the amount of CO2 supplied by the cylinders and hence the CO2 cost in a commercial CSAL.
Deterioration of Potentially Biodegradable Alternatives to Black Plastic Mulch in Three Tomato Production Regions
Authors: Miles Carol , Wallace Russ , Wszelaki Annette , Martin Jeffrey , Cowan Jeremy , Walters Tom , Inglis Debra
Published: February 2019

Four potentially biodegradable mulch products (BioAgri, BioTelo, WeedGuardPlus, and SB-PLA-10) were evaluated during 2010 in three contrasting regions of the United States (Knoxville, TN; Lubbock, TX; and Mount Vernon, WA) and compared with black plastic mulch and a no-mulch control for durability, weed control, and impact on tomato yield in high tunnel and open field production systems. WeedGuardPlus, BioTelo, and BioAgri had the greatest number of rips, tears, and holes (RTH) and percent visually observed deterioration (PVD) at all three sites (P ≤ 0.05), and values were greater in the open field than high tunnels, likely as a result of high winds and greater solar radiation and rainfall. SB-PLA-10 showed essentially no deterioration at all three sites and was equivalent to black plastic in both high tunnels and the open field. Weed growth at the sites did not differ in high tunnels as compared with the open field (P > 0.05). Weed growth at Knoxville and Mount Vernon was greatest under SB-PLA-10 (P ≤ 0.02), likely as a result of the white, translucent nature of this test product. Tomato yield was greater in the high tunnels than open field at all three sites (P ≤ 0.03), except for total fruit weight at Knoxville (P ≤ 0.53). Total number of tomato fruit and total fruit weight were lowest for bare ground at both Knoxville (150 × 104 fruit/ha and 29 t·ha−1; P ≤ 0.04) and Mount Vernon (44 × 104 fruit/ha and 11 t·ha−1; P ≤ 0.008). At Knoxville, the other mulch treatments were statistically equivalent, whereas at Mount Vernon, BioAgri had among the highest yields (66 × 104 fruit/ha and 16 t·ha−1). There were no differences in tomato yield resulting from mulch type at Lubbock.
Rose Phytoene Desaturase Gene Silencing by Apple Latent Spherical Virus Vectors
Authors: Ito Hiroaki , Ochiai Masaki , Kato Hiroaki , Shiratake Katsuhiro , Takemoto Daigo , Otagaki Shungo , Matsumoto Shogo
Published: February 2019

We have succeeded in establishing a virus-induced gene silencing (VIGS) of rose using Apple latent spherical virus (ALSV) vectors. An ALSV infection on rose did not cause any symptoms like those observed on other plant species and grew healthy. We have cloned and sequenced the phytoene desaturase (PDS) gene in wild rose, then used its fragment for silencing the rose internal PDS gene. The silencing phenotypes such as the highly uniform photo-bleached phenotype with PDS inhibitions were observed on the upper leaves of primary shoots and on a secondary shoot of R. rugosa for more than 5 months. ALSV vectors seemed useful for analyzing gene function and for the molecular breeding of rose.
High Tunnel and Field Production of Organic Heirloom Tomatoes: Yield, Fruit Quality, Disease, and Microclimate
Authors: O’Connell Suzanne , Rivard Cary , Peet Mary M. , Harlow Chris , Louws Frank
Published: February 2019

Organic and heirloom tomatoes are high-value products with growing demand but there are many challenges to successful cultivation. A systems comparison study was carried out to evaluate the production of the popular heirloom tomato ‘Cherokee Purple’ (Solanum lycopersicum L.) under high tunnel and open field systems in North Carolina from 2007 to 2008. Management of the high tunnel (i.e., temperature and irrigation), weather events as well as pest and disease pressure influenced crop quality and yield. The high tunnel and field systems achieved similar total yields (100 t·ha−1) the first season but yields were 33% greater in the high tunnel system than the field system in the second year (100 t·ha−1 and 67 t·ha−1, respectively). Both years, the tomatoes were planted in high tunnels 1 month earlier and harvested 3 weeks earlier than the field. The accumulation of ≈1100 growing degree-days (GDD) was required in both systems before 50% of the fruit was harvested. Fruit cracking, cat-facing, blossom-end rot, and insect damage were the major categories of defects in both systems. Incidence of both Tomato Spotted Wilt Virus (TSWV) and Gray Leaf Spot (GLS) were lower in the high tunnel compared with the field in 2007 and 2008, respectively. Results of this study suggest that with proper management techniques, high tunnels can optimize yields, increase fruit quality, and provide season extension opportunities for high-value horticultural crops.
Ethephon Substrate Drenches Inhibit Stem Extension of Floriculture Crops
Authors: Miller William B. , Mattson Neil S. , Xie Xiaorong , Xu Danghui , Currey Christopher J. , Clemens Kasey L. , Lopez Roberto G. , Olrich Michael , Runkle Erik S.
Published: February 2019

Ethephon [(2-chloroethyl) phosphonic acid] is a plant growth regulator that releases ethylene on application and can abort flowers, stimulate branching, and inhibit stem elongation. Although ethephon is used as a foliar spray during the commercial production of many ornamental crops, its effectiveness as a drench has not been widely investigated. We performed experiments to quantify the effects of an ethephon drench on growth and flowering of a range of bedding plant and Narcissus cultivars and to assess the effect of lime on ethylene release from a peat substrate. A substrate drench of 0, 100, 250, or 500 mg·L−1 ethephon was applied to 12 potted Narcissus cultivars at one location, and up to 200 mg·L−1 was applied to 24 cultivars of bedding plants at three locations. Compared with untreated controls, ethephon generally reduced plant height at flowering and the effect increased with increased concentration. For example, Narcissus treated with a 250 mg·L−1 ethephon drench had stems that were 20% to 40% shorter at the end of flowering than control plants. However, ethephon drenches generally caused a 2- to 3-day flowering delay, and two cultivars had a phytotoxic response. Among the bedding plants studied, a 100-mg·L−1 ethephon drench suppressed plant height at flowering by greater than 30% in Catharanthus, Celosia, Dianthus, and Verbena, but by only 10% to 15% in Lobelia, Lycopersicon, and Tagetes. The drenches also delayed flowering in 10 of the 16 crops measured and decreased dry mass accumulation in all of the crops measured. Ethephon release from peat substrate became maximal ≈120 h after application and was dramatically increased by incorporation of dolomitic lime up to a rate of 9.5 kg lime per m3 of peat. Collectively, these studies show that ethephon substrate drenches inhibit stem elongation in a broad range of floriculture crops, but can also delay flowering and reduce biomass accumulation.
Technical and Socioeconomic Challenges to Setting and Implementing Priorities in North American Rosaceous Fruit Breeding Programs
Authors: Yue Chengyan , Gallardo R. Karina , McCracken Vicki A. , Luby James , McFerson James R. , Liu Lan , Iezzoni Amy
Published: February 2019

Rosaceous crops (e.g., almond, apple, apricot, caneberry, cherry, pear, peach, plum, rose, and strawberry) contribute to human health and well-being and collectively constitute the economic backbone of numerous North American rural communities. We conducted a survey of U.S. and Canadian rosaceous fruit crop breeders to assess priority setting in their programs, sources of information for setting priorities, and challenges in making technical and management decisions. Input from producers and consumers was most important in establishing breeding program targets, although respondents’ direct interaction with consumers was not frequent. Breeding targets and management decisions were mostly associated with the breeder’s type of organization, scope and range of crops, and intended use of the crop (fresh, processed, or both).
Classification of Kentucky Bluegrass (Poa pratensis L.) Cultivars and Accessions Based on Microsatellite (Simple Sequence Repeat) Markers
Authors: Honig Josh A. , Averello Vincenzo , Bonos Stacy A. , Meyer William A.
Published: February 2019

Kentucky bluegrass (Poa pratensis L.) is an important facultative apomictic temperate perennial grass species used for both forage and cultivated turf. Through apomixis, this species is able to propagate diverse and odd ploidy levels, resulting in many genetically distinct phenotypes. A wide range of diverse cultivars and accessions of kentucky bluegrass have been previously characterized based on pedigree, common turf performance, and morphological characteristics to create a kentucky bluegrass cultivar classification system. The objectives of the current study were to assess the amount of genetic divergence among kentucky bluegrass cultivars, experimental selections, and plant collections and revise/update the original pedigree, turf performance, and morphological characteristics kentucky bluegrass classification system using recently described kentucky bluegrass microsatellite [simple sequence repeat (SSR)] markers. In this study, 247 kentucky bluegrass cultivars, experimental selections, and collections were genotyped using 25 SSR markers. SSR markers showed a strong correlation between genetic relatedness as assessed by molecular markers and the original kentucky bluegrass classification system and also provided justification for a revision/update of the classification system. Traditional classification types that were supported by the current SSR analysis include BVMG, Compact, Compact-America, Julia, Mid-Atlantic, Midnight, and Shamrock types. Newly proposed classification types included Cynthia, Jefferson/Washington, Limousine, P-105, Sydsport, and three Eurasian types. The majority of cultivars, experimental selections, and collections were uniquely identified with the current set of SSR markers. Genetic relationships of individuals as assessed by SSR markers closely matched known pedigrees. The current set of SSR markers can be used to rapidly genotype and assign new cultivars/accessions to kentucky bluegrass classification types and assess genetic relatedness among individuals and should be considered for use in a kentucky bluegrass plant variety protection program.
Evaluation of Substrate Hydraulic Properties Amended by Urea–formaldehyde Resin Foam
Authors: Londra Paraskevi A. , Psychoyou Maria , Valiantzas John D.
Published: February 2019

Urea–formaldehyde resin foam has been introduced as a synthetic organic soil amendment and is used in hydroponic systems, soilless cultures, production of container-grown plants, roof gardens, and sports fields. To evaluate whether urea–formaldehyde resin foam can improve physical properties (water retention capacity and aeration) of horticultural substrates, an organic substrate (coir) and an inorganic soil (loam soil) were selected and amended with urea–formaldehyde resin foam (Fytocell). Water retention curves, θ(h), saturated hydraulic conductivity, Ks, and the relationship between unsaturated hydraulic conductivity and volumetric water content, K(θ), were determined for Fytocell, coir, loam soil, mixtures of coir/Fytocell (60/40 v/v), and loam soil/Fytocell (60/40 v/v). Water retention curves indicated that the addition of Fytocell in loam soil and coir mixtures increased and decreased, respectively, the water retention capacity. The Ks of loam soil and coir mixtures were decreased and increased, respectively, by the addition of Fytocell. In all substrates studied, K(θ) decreased sharply when θ decreased from 0.80 to 0.20 m3·m−3. However, the coir/Fytocell mix had the highest values of K(θ) when θ was below 0.40 m3·m−3. Moreover, the comparison between estimated K(θ) values obtained using the experimental outflow method of Valiantzas (1989) and predicted values using the van Genuchten–Mualem model showed a satisfactory agreement (0.937 0.996) for the substrates examined.
Evaluation of Apple (Malus ×domestica) Genetic Resources in Bosnia and Herzegovina Using Microsatellite Markers
Authors: Gasi Fuad , Simon Silvio , Pojskic Naris , Kurtovic Mirsad , Pejic Ivan , Meland Mekjell , Kaiser Clive
Published: February 2019

There is a need for classifying and conserving local apple cultivars from two main regions in Bosnia and Herzegovina (B&H). Consequently, 71 local apple accessions (31 from Sarajevo and 40 from eastern Bosnia) were evaluated with a set of 10 simple sequence repeats (SSRs). These accessions were compared with 37 reference cultivars (24 traditional B&H and 13 international cultivars maintained at the ex situ collection Srebrenik) to determine synonyms, homonyms, and possible introgression of foreign genotypes into the local apple germplasm. Using 10 primer pairs of microsatellites, we were able to amplify 135 alleles for the 71 local apple accessions. Detection of more than two different alleles per locus was observed for 34 accessions. Fourteen different homonyms and 12 synonyms were identified among all the apple cultivars analyzed. Analysis of molecular variance (AMOVA) revealed a significant genetic differentiation between most of the groups analyzed but not between accessions from Sarajevo and eastern Bosnia. Bayesian method and admixture analysis of the allele frequency allowed classification of all accessions analyzed and found that they fell into two main groups [reconstructed panmictic populations (RPPs)]. Strong genetic differentiation between these two groups was detected using AMOVA (fCT = 0.130; P < 0.001). Analysis of the genetic structure indicates that overall, approximately half of the local apple cultivars from Sarajevo and eastern Bosnia (52% and 45%, respectively) grouped in the RPP1 consisting mainly out of international reference cultivars, whereas the other half grouped in the RPP2 with traditional B&H reference cultivars. Both neighbor joining (NJ) cluster analysis based on Bruvo genetic distance and factorial correspondence analysis (FCA) confirmed the results of the genetic structure analysis. The molecular data show that both apple accessions from Sarajevo and from eastern Bosnia represent an interesting source of diversity, which needs to be conserved.
Vertical Stratification of Predation on Aulacaspis yasumatsui Infesting Cycas micronesica Seedlings
Authors: Marler Thomas E. , Miller Ross , Moore Aubrey
Published: February 2019

Container-grown Cycas micronesica seedlings were purposefully infested with Aulacaspis yasumatsui and then installed at 0, 75, or 150 cm above the ground to investigate effects of infestation height on predation by Rhyzobius lophanthae. Significantly more scales on elevated seedlings were attacked by the predator. Our results indicate that lower predation at ground level by R. lophanthae may partly explain why the predator is not effectively controlling this armored scale epidemic on Guam. Ephemeral outbreaks of A. yasumatsui documented in quarterly surveys from Sept. 2006 until Aug. 2012 confirm the inadequate biological control. Our results illuminate the importance of fully evaluating the reliance on an alien predator as a solo biological control agent for an alien pest.
Dark-stored Flurprimidol Solutions Maintain Efficacy Over Many Weeks
Authors: Miller William B.
Published: February 2019

For a number of geophytic crops, pre-plant plant growth regulator (PGR) dips or soaks are an effective method of height control. Previous research has shown that a given PGR solution may be used to dip numerous bulbs without losing efficacy. What has been unknown is whether PGR solutions maintain efficacy over multiple-week (seasonal) time scales, especially if they have previously been used to treat bulbs. To address this question, 30 mg·L−1 flurprimidol solutions were prepared 3 weeks apart and used to dip narcissus and hyacinth bulbs and then held for 4 weeks at 17 °C in darkness. These solutions (now 7 and 4 weeks old) and a freshly prepared solution were used to dip bulbs of eight hyacinth and five narcissus cultivars. After appropriate cooling, bulbs were forced in a greenhouse. Results indicate no difference in growth reduction among the 0-, 4-, or 7-week-old solutions demonstrating no loss of PGR activity over a 7-week period. In two other experiments, 2.5, 5, and 10 mg·L−1 flurprimidol solutions were exposed to 0 to 8 days of full sun (late June) and then used to dip Lilium ‘Tresor’ bulbs for 1 minute. Growth of the plants indicated loss of growth regulation activity (taller plants) as the duration of exposure to sunlight increased, suggesting substantial photolysis of the active ingredient. Together, the results suggest that flurprimidol solutions can be held in darkness at 17 °C and used for at least 7 weeks without loss of efficacy.
Physiological and Psychological Response to Floral Scent
Authors: Jo Hyunju , Rodiek Susan , Fujii Eijiro , Miyazaki Yoshifumi , Park Bum-Jin , Ann Seoung-Won
Published: February 2019

To better understand how fragrance may enhance human health, this study examined psychophysiological responses to Japanese plum blossom fragrance. Although previous studies used essential oils or fragrance components, the present study measured the effects of floral scent naturally diffused by the plant itself to simulate the way we generally experience natural scent in everyday life. Subjects were Japanese males (n = 26), and the data collected included cerebral and autonomic nervous system activities, semantic differential (SD) scale, and profile of mood states (POMS). Exposure to the fragrance significantly activated the sympathetic nervous system and the cerebral areas related to movement, speech, and memory. SD scale and POMS results showed the fragrance evoked cheerful, exciting, and active images and changed mood states by enhancing vigor while suppressing feelings of depression. These findings indicate that contact with a floral scent such as plum blossom fragrance can improve mood states and may foster the brain functions of memory, speech, and movement, potentially leading to improvements in emotional health, depression, and memory disorders.
Inheritance of Resistance to Powdery Mildew Race 2 in Citrullus lanatus var. lanatus
Authors: Tetteh Antonia Y. , Wehner Todd C. , Davis Angela R.
Published: February 2019

Information on the mode of inheritance of powdery mildew resistance in watermelon is important for designing a breeding strategy for the development of new cultivars. Resistance in the watermelon accession PI 270545 was investigated by generation means analysis by crossing it with susceptible PI 267677. The analyses showed involvement of two genes, a recessive resistance gene, pmr-1, and a dominant gene for moderate resistance, Pmr-2. Resistance to powdery mildew in the leaf had a large dominance effect and a heritability of 71%. The additive-dominance model was inadequate in explaining variation in leaf resistance as revealed by the joint scaling test. However, nonallelic interactions could not be detected by the nonweighted six-parameter scaling test. For stem resistance, the additive-dominance model was adequate, and inheritance was controlled mainly by additive effects. A high narrow-sense heritability of 79% suggested that selection for stem resistance in early generations would be effective.
Variation for Resistance to White Rust (Puccinia horiana) among Ajania and Chrysanthemum Species
Authors: Zeng Jun , Sun Jing , Xu Yang , Chen Fadi , Jiang Jiafu , Fang Weiming , Chen Sumei
Published: February 2019

White rust (causative pathogen Puccinia horiana) is a destructive disease of commercial chrysanthemum crops. A panel of 19 accessions of commercial chrysanthemum near-relatives (four Ajania species, 11 Chrysanthemum species including five accessions of Chrysanthemum indicum) were screened for their reaction to white rust infection in separate greenhouse trials carried out at two independent sites in eastern China, one in 2010 and the other in 2012. The reaction of the accessions to artificial inoculation ranged from immune to highly susceptible. Accessions of Chrysanthemum indicum, C. yoshinaganthum, C. makinoi var. wakasaense, C. nankingense, C. vestitum, C. lavandulifolium, C. crassum, and Ajania tripinnatisecta were immune, and strong resistance was present in C. japonense, C. × shimotomaii, and A. przewalskii. Most of the accessions behaved similarly in the two trials, but two of the C. indicum accessions produced inconsistent results, each being highly resistant in one trial but susceptible in the other. Because wide crosses are relatively easy to achieve in the chrysanthemum complex, these immune and highly resistant accessions represent promising germplasm for white rust resistance breeding.
Fruit Anthocyanin Profile and Berry Color of Muscadine Grape Cultivars and Muscadinia Germplasm
Authors: Conner Patrick J. , MacLean Dan
Published: February 2019

Anthocyanin content and composition and CIE 1976 (L*, a*, b*) color space (CIELAB) color coordinates were examined for the skin of 22 muscadine grape (Vitis rotundifolia Michx.) cultivars and Muscadinia Planch germplasm. Analysis of berry skin extracts by high-performance liquid chromatography (HPLC) determined that anthocyanin content varied from less than 100 μg·g−1 in bronze and pink berries to over 5500 μg·g−1 in highly pigmented black berries. The anthocyanins delphinidin, cyanidin, petunidin, pelargonidin, peonidin, and malvidin were detected in their 3,5-diglucosidic forms. Analysis of berry color with a colorimeter revealed chroma (C*) ranged from 2.4 to 22.8 with the highest values occurring in bronze- and red-colored berries. As anthocyanin concentration increased, lightness (L*) decreased to a low of 20 to 23 in black-colored berries. Pink and red skin colors were primarily a result of lower levels of total anthocyanins, although there was also a shift away from delphinidin and petunidin production toward more cyanidin and peonidin. Malvidin, the most important anthocyanin for muscadine wine and juice color stability, was only abundant in a few clones, all of which had V. munsoniana (Simpson ex Munson) Small or V. popenoei (Fennell) Small in their pedigree. The interspecific hybrid ‘Fennell’s 3-way Hybrid’ had the largest proportion of malvidin, contributing ≈58% of the total anthocyanin content. This clone also had low levels of delphinidin and high total levels of anthocyanin, making it a promising source for the improvement of muscadine grape pigment profiles.
Kin Recognition Alters Root and Whole Plant Growth of Split-root Cycas edentata Seedlings
Authors: Marler Thomas E.
Published: February 2019

Split-root techniques were used to determine if Cycas edentata seedling roots possessed identity recognition capabilities. One compartment of the split-root containers contained a competing half-sibling seedling, and the second compartment contained one of four treatments. When the second compartment contained a half-sibling or C. edentata seedling from the same habitat, root growth did not differ between compartments. When the second compartment contained a C. edentata seedling from a habitat 130 km away or a C. nitida seedling, root dry weight and root length were increased above that of compartments with half-siblings. Whole plant growth also increased in seedlings that experienced competition with the conspecific plant from a distant habitat or from a different species. The results validated the ability of Cycas edentata roots to recognize and then use a plastic response to neighbor root identity. In horticultural settings, planting cycad plants where neighbors are close relatives may reduce plant growth, and planting to ensure neighbors are not close relatives may increase plant growth.
Ripening-dependent Changes in Phytonutrients and Antioxidant Activity of Red Pepper (Capsicum annuum L.) Fruits Cultivated under Open-field Conditions
Authors: Bhandari Shiva Ram , Jung Bo-Deul , Baek Hum-Young , Lee Young-Sang
Published: February 2019

To understand ripening-dependent changes in phytonutrients, five commercial cultivars of red peppers (Capsicum annuum L.) grown in an open field in Taean, South Korea, were selected and their fruits were harvested at green mature (GM), intermediate breaker (BR), and red ripe (RR) stages and their phytonutrient contents and antioxidant activities were compared. Three major patterns in relation to ripening progress were observed. First, continuous increases were observed in vitamin C, total phenol, vitamin E (especially α-tocopherol), total free sugar, β-carotene, linolenic acid content, and antioxidant activity. Second, decreasing patterns were observed in phytosterols (campesterol, stigmasterol, and β-sitosterol) and linoleic acid. Third, total flavonoid and squalene contents were relatively higher at the BR stage compared with the GM and RR stages. These results indicate that each phytonutrient has a unique pattern of accumulation and degradation during the fruit-maturing process. Unlike the mentioned phytonutrients, which showed similar patterns in all tested cultivars, capsaicinoids exhibited quite different patterns of ripening-dependent changes among the cultivars. Throughout the ripening processes, positive correlations with antioxidant activity were observed in vitamin E (r = 0.814**), β-carotene (r = 0.772*), vitamin C (r = 0.610**), and total phenol (r = 0.595**) contents, whereas capsaicinoids, total flavonoid, and phytosterols exhibited no or slightly negative correlations. In conclusion, the ripening of red pepper fruits is accompanied by continuous increments in various phytonutrients and subsequent antioxidant activity.
Storage of ‘Oso Grande’ Strawberries in Controlled Atmosphere Containing Nitrous Oxide (N2O)
Authors: Cunha Júnior Luís Carlos , Jacomino Ângelo Pedro , Trevisan Marcos José , Henrique de Almeida Teixeira Gustavo
Published: February 2019

The objective of this study was to evaluate the quality of ‘Oso Grande’ strawberries during controlled atmosphere (CA) storage with different concentrations of nitrous oxide (N2O). The strawberries were stored at 10 °C for 10 days in hermetic mini-chambers with a continuous flow of 2.5 10−6 m3·s−1 of gaseous mixtures of N2O at 10 kPa, 30 kPa, 60 kPa, and 80 kPa combined with 21 kPa O2 balanced with nitrogen (N2) or in 21 kPa O2, 0.03 kPa CO2, and 0 kPa N2O (control). Strawberries stored in the atmospheres that contained N2O exhibited a reduced incidence of decay and presented better quality than the control group. After 10 days of storage, 37.2% decay was observed in the control group fruit, and 13.6% and 16.4% decay was observed in the fruit maintained at 60 kPa and 80 kPa N2O, respectively. There was a significant reduction (P < 0.05) of 36% in the respiratory rate of the fruit maintained in the CA containing N2O, and the levels of acetaldehyde (0.004 to 0.008 g·kg-1) and ethanol (0.006 to 0.016 g·kg-1) were unaffected by the treatments. The N2O concentrations of 60 kPa and 80 kPa proved to be more adequate for storing the ‘Oso Grande’ strawberries because they reduce the incidence of decay, lowered the respiratory rate, and maintained the quality of the fruit.
Distillation Time Effect on Essential Oil Yield, Composition, and Antioxidant Capacity of Sweet Sagewort (Artemisia annua L.) Oil
Authors: Zheljazkov Valtcho D. , Astatkie Tess , Horgan Thomas , Schlegel Vicki , Simonnet Xavier
Published: February 2019

Sweet sagewort, also known as sweet wormwood (Artemisia annua L.), contains essential oil and other natural products. The objective of this study was to evaluate the effect of eight different distillation times (DTs; 1.25 minutes, 2.5 minutes, 5 minutes, 10 minutes, 20 minutes, 40 minutes, 80 minutes, and 160 minutes) on A. annua essential oil and its antioxidant capacity. Highest essential oil yield was achieved at 160-minute DT. The concentration of camphor (8.7% to 50% in the oil) was highest at the shorter DT and reached a minimum at 160-minute DT. The concentration of borneol showed a similar trend as the concentration of camphor. The concentrations of some constituents in the oil were highest at 2.5-minute DT (alpha-pinene and camphene), at 10 minutes (paracymene), at 20 minutes (beta-chamigrene and gamma-himachalene), at 80 minutes [transmuurola-4(15),5-diene and spathulenol], at 80- to 160-minute DT (caryophylene oxide and cis-cadin-4-en-ol), or at 160-minute DT (beta-caryophyllene, transbeta-farnesene, and germacrene-D). The yield of individual constituents reached maximum at 20- to 160-minute DT (camphor) at 80- to 160-minute DT [paracymene, borneol, transmuurola-4(15),5-diene, and spathulenol], or at 160-minute DT (for the rest of the oil constituents). DT can be used to attain A. annua essential oil with differential and possibly targeted specific chemical profile. The highest antioxidant capacity of the oil was obtained at 20-minute DT and the lowest from the oil in the 5-minute DT. This study suggests that literature reports on essential oil content and composition of A. annua could be compared only if the essential oil was extracted at similar DTs. Therefore, DT must be reported when reporting data on essential oil content and composition of A. annua.