bluuebunny/crossref_metadata_2025 huggingface dataset:
Price Elasticities of Demand for Mums and Pansies Sold in Independent Garden Centers
Authors: Wohlgenant Michael K. , Safley Charles D. , Rezitis Anthony N.
Published: February 2019

Data from a survey of North Carolina independent garden center customers in Fall 1996 were used to determine the price responsiveness of mums and pansies. A survey was conducted of four garden centers in the Raleigh, N.C., area and four garden centers operating in the Triad marketing area (Greensboro, Winston-Salem, and High Point, N.C.). Information collected on 1608 consumers included various socioeconomic and demographic variables (age, value of residence, type of residence, number of years in the residence, housing tenure, and employment status) as well as plant purchase information (plant price, plant types, and plant sizes). Price responsiveness of consumers was estimated by analyzing how customers' responses change as prices varied from one store to another and from one location to another. Measures of price responsiveness indicated statistically significant price elasticities of demand of -0.76 for mums and -0.80 for pansies. These elasticities can be used to indicate how industry sales would respond to a change to the industry that affects all firms in the same way—such as the response to an increase in energy costs. The paper shows how to use the elasticities to develop particular pricing strategies under different circumstances facing firms in the industry.
Regeneration In Vitro From the Hypocotyl of Cucumis Species Produces Almost Exclusively Diploid Shoots, and Does Not Require Light
Authors: Curuk Sebahattin , Ananthakrishnan G. , Singer Sima , Xia Xiaodi , Elman Chassia , Nestel David , Cetiner Selim , Gaba Victor
Published: February 2019

Hypocotyl explants of three cultivars of melon (Cucumis melo L.) (cvs. Revigal, Topmark and Kirkagac), and a cucumber (C. sativus L. cv. Taoz) rapidly directly regenerated multiple shoots on Murashige and Skoog medium augmented with 4.4 μm benzyladenine. Regeneration from the hypocotyl resulted in nearly 100% diploid shoots, whereas regeneration from the cotyledons resulted in 40% to 70% polyploid regenerants. Regeneration from cotyledon explants of melon cv. Revigal required light, whereas regeneration from hypocotyl explants of melon cv. Revigal occurred in both light and darkness. Direct regeneration also occurred from the hypocotyl of cucumber cv. Taoz in both light and darkness, even though cotyledonary explants did not regenerate buds or shoots under the same conditions. This is the first report of regeneration from the Cucumis genus producing a fully diploid plant population.
Light Intensity Affects Gibberellic Acid Content in Kentucky Bluegrass
Authors: Tan Z.G. , Qian Y.L.
Published: February 2019

Turfgrasses grown under low light conditions generally exhibit increased shoot elongation. Gibberellic acids (GAs), GA1 in particular, promote stem elongation in grass species. GA20 is the immediate precursor of GA1. However, a direct quantitative measurement of GA1 and GA20 has not been reported for turfgrass under different light intensities. This study was conducted in a greenhouse to quantify the endogenous levels of GA1 and GA20 of `KenblueTimes', `Livingston', and `NuGlade' Kentucky bluegrass (Poa pratensis L.) under two light intensities with and without trinexapacethyl (TE) application. GA1 and GA20 content in leaf tissue were analyzed using gas chromatography-mass spectrometry with deuterium-labeled GA1 and GA20 as internal standards. Light reduction of 73% under greenhouse conditions increased GA1 by 44% to 47% and GA20 by 16% to 50%. `NuGlade' had a GA1 content 20% lower than that of `Kenblue', suggesting that the dwarf characteristics of `NuGlade' may be related to its low GA1 content. The application of TE (0.1 kg·ha-1) reduced GA1 concentration by 47%, but increased GA20 concentration by 146%, supporting the contention that TE inhibited GA1 biosynthesis by blocking the conversion of GA20 to GA1. Chemical names used: 4-(cyclopropyl- -hydroxy-methylene)-3,5-dioxo-cyclohexanecarboxylic acid ethyl ester (trinexapac-ethyl); gibberellic acid (GA).
Consumer Purchases of Campanula carpatica Jacq. 'Blue Clips' in Selected Supermarket Floral Departments as an Indoor Flowering Potted Plant
Authors: Kelley Kathleen M. , Behe Bridget K. , Moore Elizabeth H.
Published: February 2019

Four-inch (10.2-cm) potted floweringCampanula carpatica Jacq. 'Blue Clips' (campanula) traditional herbaceous perennials, were sold in floral departments of three retail supermarket chain stores from 5 May through 20 May and 16 June through 1 July 2000. The intent was to determine whether repositioning campanula as a “new” indoor flowering potted plant would add to total floral department sales or detract from sales of more traditional flowering potted plants. Unit sales for all 4- and 4.5-inch (10.2- and 11.3-cm) flowering potted plants stocked in three supermarket floral departments were recorded weekly and compared with unit sales from three stores where campanula were not sold (control). Unit sales for campanula were similar to those of traditional indoor flowering potted plants frequently stocked in floral departments. Statistical analysis showed that mean unit sales of traditional potted flowering plants for stores that did and did not stock campanula were similar. Therefore, adding campanula to the flowering potted plant mix did not detract from or jeopardize sales of similar indoor flowering potted plants.
Majin: A Miniature DNA Element Associated with the Genomes of Pome Fruit Trees
Authors: Wakasa Y. , Ishikawa R. , Niizeki M. , Harada T. , Jin S. , Senda M. , Akada S.
Published: February 2019

Sequencing of the sequence tagged site-DNA marker fragments linked to the fruit skin-color gene in apple revealed two fragments containing insertions that are associated with yellow skin color, and are alleles of the red skin gene (Rf). One fragment resulted from the insertion of a 76-bp inverted repeat, whereas the 163 bp in the other fragment was characterized as a mobile element because of the presence of target site duplication. A database search found this latter element in the 5' flanking regions or intron of six apple genes. DNA blot analysis revealed that the element is highly reiterated, with a copy number of between 5000-6000 in the genome of Maloideae (pome) fruit trees. We named this element Majin. Inter-transposon amplified polymorphism using primers from this element resulted in polymorphic bands among apple cultivars.
The pH-Response of a Peat-based Medium to Application of Acid-reaction Chemicals
Authors: Bishko A. Jeremy , Fisher Paul R. , Argo William R.
Published: February 2019

Medium-pH above 6.4 is a common cause of micronutrient deficiency for container-grown plants, and technologies are required to correct an excessively high medium-pH. The objective was to quantify the dose response from application of several acidic materials that have been recommended for lowering medium-pH in soilless media. A 70% peat/30% perlite (by volume) medium was mixed with a preplant nutrient charge, a wetting agent and 1.5, 1.8, 2.1, or 2.4 kg·m-3 of a dolomitic hydrated lime resulting in four starting pH levels ranging from 6.4 to 7.6. Aluminum sulfate (17% Al) at 1.8-28.8 g·L-1, flowable elemental sulfur (52% S) at 3.55-56.8 mL·L-1, ferrous sulfate (20.8% Fe) at 1.8-28.8 g·L-1, Seplex-L organic acid at 0.32-5.12 mL·L-1, sulfuric acid (93%) at 0.08-2.56 mL·L-1, 21.1N-3.1P-5.8K water-soluble fertilizer at 50-400 mg·L-1 N (potential acidity 780 g CaCO3 equivalents/kg), and a deionized water control were applied at 60 mL per 126-cm3 container with minimal leaching as a single drench (except repeat sulfuric acid applications at 0.08 or 0.16 mL·L-1 and 21.1N-3.1P-5.8K treatments that were applied about every 3 days). Medium-pH and electrical conductivity (EC) were tested over 28 days using the saturated medium extract method using deionized water as the extractant. One day after application, aluminum sulfate, ferrous sulfate, and sulfuric acid lowered pH by up to 3 pH units at the highest concentrations and medium-pH remained fairly stable for the following 27 days. Flowable sulfur lowered pH gradually over the course of the experiment by up to 3.3 pH units, with no difference across the wide range in concentrations. Organic acid had minimal impact on medium-pH, and 21.1N-3.1P-5.8K did not lower medium-pH despite the fact that all nitrogen was supplied in the ammonium and urea form. At recommended concentrations, chemicals tested raised medium-EC, but not above acceptable levels for plant growth. The highest rates of aluminum and ferrous sulfates, and sulfuric acid, however, increased medium-EC by 2.0 dS·m-1 on day 1. Medium-pH-responses to acid-reaction chemicals would be expected to vary in commercial practices depending on additional factors such as lime type and incorporation rate, water alkalinity, media components, and plant interactions.
Nitrogen Level and Form Affect Taro Growth and Nutrition
Authors: Osorio N.W. , Shuai X. , Miyasaka S. , Wang B. , Shirey R.L. , Wigmore W.J.
Published: February 2019

Nitrogen (N) is often the most limiting mineral nutrient for taro growth. Two experiments were carried out under hydroponics conditions to determine the effects of varying solution N levels and N form on taro (Colocasia esculenta L. Schott cv. Bun Long) growth and foliar nutrient concentrations for 42 days. In the first experiment, taro plants were grown at six NH4NO3 levels (0, 0.25, 0.5, 1.0, 2.0, and 4.0 mm N). In the second experiment, taro plants were grown at a total N level of 3 mm with five nitrate (NO3-): ammonium (NH4+) percent molar ratios (100:0, 75:25, 50:50, 25:75, and 0:100). In the N level experiment, dry matter and leaf area increased up to 2 mm N and then decreased at the highest N level. The reduced growth of taro at the highest N level was attributed in part to a high NH4+ level that reduced uptake or translocation of cations, such as Ca2+, Mg2+, and Mn2+. Nitrogen concentration in leaf blades increased with increasing N levels. The critical foliar N concentration that coincided with 95% of maximum growth based on a quadratic model was 40.4 g·kg-1 (dry weight basis). In the N form experiment, NO3-: NH4+ ratios of 75:25 or 100:0 favored greater plant growth compared to other treatments. Taro plants grown in NH4+-rich solutions drastically acidified the solution pH, and had retarded growth and smaller leaf area compared to those grown in NO3--rich solutions.
Growth and Nutrient Use of Ericaceous Plants Grown in Media Amended with Sphagnum Moss Peat or Coir Dust
Authors: Scagel Carolyn F.
Published: February 2019

Using several different ericaceous ornamental species, we compared the growth, mineral nutrition, and composition of plants in response to growing media amended with varying proportions of sphagnum moss peat (peat) or coir dust (coir). Plants were grown for 16 weeks in media consisting of 80% composted Douglas fir bark with 20% peat, 20% coir, or 10% peat and 10% coir. Sixteen weeks after planting, decreases in extractable P were larger in peat-amended medium than the coir-amended medium, while decreases in extractable NH4-N and NO3-N were larger in the coir-amended medium. In general, leaf and stem dry weight, the number of leaves and stems, and total stem length increased with increasing proportion of coir in the medium while root dry weight either increased (Kalmia latifolia), decreased (Rhododendron, Gaultheria), or was not influenced by increasing the proportion of coir in the medium. The composition of the growing medium also influenced aspects of plant marketability and quality including: leaf greenness (SPAD), plant form (e.g., number of leaves per length of stem), and partitioning of biomass (e.g., root to shoot ratio). Nutrient uptake and fertilizer use was significantly different between the media types. Depending on the cultivar, we found that the coir-amended medium resulted in higher uptake or availability of several nutrients than peat-amended medium. Up take or availability of N, P, K, Ca, and S was enhanced for several cultivars, while uptake or availability of Mg, Fe, and B was similar between media types. Most cultivars/species growing in the coir-amended medium had higher production or accumulation of proteins and amino acids in stems than plants growing in peat-amended medium, while the production of proteins and amino acids in roots was lower in plants growing in coir-amended than in peat-amended medium. For the cultivars/species we tested, coir is a suitable media amendment for growing ericaceous plants and may have beneficial effects on plant quality.
Weed Control in Strawberry Provided by Shank- and Drip-applied Methyl Bromide Alternative Fumigants
Authors: Fennimore S.A. , Haar M.J. , Ajwa H.A.
Published: February 2019

The loss of methyl bromide (MB) as a soil fumigant has created the need for new weed management systems for crops such as strawberry (Fragaria ×ananassa Duchesne). Potential alternative chemicals to replace methyl bromide fumigation include 1,3-D, chloropicrin (CP), and metam sodium. Application of emulsified formulations of these fumigants through the drip irrigation system is being tested as an alternative to the standard shank injection method of fumigant application in strawberry production. The goal of this research was to evaluate the weed control efficacy of alternative fumigants applied through the drip irrigation system and by shank injection. The fumigant 1,3-D in a mixture with CP was drip-applied as InLine (60% 1,3-D plus 32% CP) at 236 and 393 L·ha-1 or shank injected as Telone C35 (62% 1,3-D plus 35% CP) at 374 L·ha-1. Chloropicrin (CP EC, 95%) was drip-applied singly at 130 and 200 L·ha-1 or shank injected (CP, 99%) at 317 kg·ha-1. Vapam HL (metam sodium 42%) was drip-applied singly at 420 and 700 L·ha-1. InLine was drip-applied at 236 and 393 L·ha-1, and then 6 d later followed by (fb) drip-applied Vapam HL at 420 and 700 L·ha-1, respectively. CP EC was drip-applied simultaneously with Vapam HL at 130 plus 420 L·ha-1 and as a sequential application at 200 fb 420 L·ha-1, respectively. Results were compared to the commercial standard, MB : CP mixture (67:33) shank-applied at 425 kg·ha-1 and the untreated control. Chloropicrin EC at 200 L·ha-1 and InLine at 236 to 393 L·ha-1 each applied singly controlled weeds as well as MB : CP at 425 kg·ha-1. Application of these fumigants through the drip irrigation systems provided equal or better weed control than equivalent rates applied by shank injection. InLine and CP EC efficacy on little mallow (Malva parviflora L.) or prostrate knotweed (Polygonum aviculare L.) seed buried at the center of the bed did not differ from MB : CP. However, the percentage of weed seed survival at the edge of the bed was often higher in the drip-applied treatments than in the shank-applied treatments, possibly due to the close proximity of the shank-injected fumigant to the edge of the bed. Vapam HL was generally less effective than MB : CP on the native weed population or on weed seed. The use of Vapam HL in combination with InLine or CP EC did not provide additional weed control benefit. Chemical names used: 1,3-dichloropropene (1,3-D); sodium N-methyldithiocarbamate (metam sodium); methyl bromide; trichloro-nitromethane (chloropicrin).
Suppression of Decline-inducing Isolates of Citrus Tristeza Virus by Nondecline-inducing Isolates
Authors: Powell Charles A. , Rundell Phyllis A. , Pelosi Robert R.
Published: February 2019

Bark chips from six container-grown citrus trees, infected with nondecline-inducing citrus tristeza virus (CTV) isolates and maintained in a vector-free greenhouse for 10 years, 15 commercial grapefruit (Citrus paradisi Macf.) trees, and 16 commercial sweet orange [C. sinensis (L.) Osbeck] trees were used to inoculate three indicator plants each of `Madam Vinous' sweet orange [C. sinensis (L.) Osbeck], sour orange (C. aurantium L.), `Duncan' grapefruit (C. paradisi Macf.), `Mexican' lime [C. aurantifolia (Christm.)], Swingle citrumelo [C. paradisi Macf. × Poncirus trifoliota (L.) Raf.], and sour orange grafted with `Hamlin' sweet orange [C. sinensis (L.) Osbeck]. All plants providing bark chips had repeatedly tested positive by enzyme-linked immunosorbent assay (ELISA) for CTV [reacted with monoclonal antibody (MAb) 17G11], but tested negative for Florida decline-inducing isolates of CTV (did not react with MAb MCA13). After 6 months in vector-free greenhouses, all in oculated trees (except Swingle citrumelo, which is considered CTV resistant) were positive for CTV by 17G11 ELISA. In addition, some indicator plants inoculated from nine (two container, two commercial grapefruit, and five commercial orange trees) of the 37 bark chip source trees also were positive for decline-inducing CTV by MCA13 ELISA. Some of these positive indicators also showed vein-clearing symptoms characteristic of infection with a severe isolate of CTV. No control, noninoculated indicators in the same greenhouse, became infected with either decline-inducing or nondecline-inducing CTV. These results indicate that decline-inducing isolates of CTV can be present as a minor component of a mixture at levels undetectable by ELISA, and that these decline-inducing isolates can become detectable by ELISA and sometimes by symptoms when inoculated into indicator plants.
Viruses Associated with Cucurbit Production in Southern Illinois
Authors: Walters S. Alan , Kindhart Jeffrey D. , Hobbs Houston A. , Eastburn Darin M.
Published: February 2019

Viruses are a serious threat to cucurbit production in southern Illinois. The most prevalent viruses infecting cucurbit crops in the region were determined during the 1998, 1999, and 2000 growing seasons to enable growers to make better decisions on viral disease management. Watermelon mosaic virus (WMV) was the most prevalent virus as it was found in ≈84% of samples over the three years. Cucumber mosaic virus (CMV), papaya ringspot virus (PRSV), squash mosaic virus (SqMV), and zucchini yellow mosaic virus (ZYMV) were detected in ≈8%, 6%, 9%, and 1% of samples, respectively, over the 3-year period. WMV was generally the only virus isolated from samples collected before mid-September. Other viruses, including CMV, PRSV, SqMV, and ZYMV, were generally first detected after mid-September and were usually found as mixed infections with WMV.
Changes in Mineral Nutrient Concentrations in Petunia Corollas during Development and Senescence
Authors: Verlinden Sven
Published: February 2019

To observe changes in the nutritional status of corollas during development and senescence, Petunia ×hybrida cv. Mitchell corollas were analyzed for macronutrient and micronutrient content, dry weight, fresh weight, and ethylene production. Carbon content decreased at slightly lower rates than dry weight during corolla development between anthesis and senescence, while fresh weight and ethylene production followed patterns expected of climacteric flowers. Nitrogen, phosphorus, and potassium content declined during development. Both phosphorus and potassium content gradually declined throughout development with overall losses of about 75% and 40%, respectively. Nitrogen content declined 50% during development but losses occurred only during the final stages of senescence. No significant changes were observed in sulfur, calcium, magnesium, and micronutrient content of the corollas during development. Most elements were present in much lower concentrations in corollas than in leaves. The concentrations of calcium, magnesium, and manganese were about 1-, 5-, and 15-fold lower in corollas than in leaves, respectively. Results indicate that remobilization of selected macronutrients from corollas occurred before and during senescence. Taken together with the presence of low concentrations of macronutrients, my data support the contention that petunia corollas are nutritionally in expensive and therefore easily disposable organs.
Screening for Resistance to Myrothecium Leaf Spot Among Syngonium Species and Cultivars
Authors: Norman D.J. , Henny R.J. , Yuen J.M.F. , Mellich T.A.
Published: February 2019

Commercially grown cultivars of Syngonium (Araceae) are very susceptible to Myrothecium leaf spot (incited by Myrothecium roridum Tode ex Fr.). Therefore, cultivation of Syngonium requires rigorous sanitation and frequent applications of fungicides for disease control. The goal of this research was to identify species and noncultivated accessions of Syngonium resistant to Myrothecium leaf spot. Five commercial cultivars and 30 accessions, comprising 16 different Syngonium species, were screened for resistance to M. roridum. All five commercial cultivars were susceptible to M. roridum. However, seven species (S. neglectum, S. wendlandii, S. dodsonianum, S. erythrophyllum, S. chiapense, S. dodsonianum, and S. angustatum) showed the highest resistance, as did two noncultivated accessions of S. podophyllum. The information on disease resistance for these species and accessions will be useful in future breeding work.
Growth and Flowering of Lantana camara L. subsp. camara as Affected by Triapenthenol and Environmental Factors
Authors: Matsoukis Aristidis S. , Chronopoulou-Sereli Aikaterini G. , Chronopoulos John K.
Published: February 2019

The various concentration effects of the growth regulator triapenthenol (0, 43.75, 87.5, 175, and 350 mg/pot) on the growth and flowering of Lantana camara L. subsp. camara under different shading levels (0%, 28%, and 66%) were studied in 1997 and 1998 in a glasshouse in Attica, Greece. It was found that minimum temperature and photosynthetic photon flux density were the most important factors to plant growth. The growth index (GI) decreased as the regulator concentration increased while the number of flower heads per plant increased up to a maximum at the concentration of 87.5 mg triapenthenol per pot with a decrease afterwards, at all shading levels. The interaction between shading level and triapenthenol concentration significantly affected GI and flowering of lantana plants. The growth index of the control plants increased and the number of flower heads per plant decreased significantly at all concentration levels examined, as shading increased from 0% to 66%. Triapenthenol resulted in darker green foliage and at higher concentrations in some leaf distortion. The most attractive plants were produced with triapenthenol concentration of 87.5 mg/pot at the nonshaded plot; they were small with the greatest number of flowers. Chemical name used: (E)-(RS)-1-cyclohexyl-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)-pent-1-en-3-ol (triapenthenol).
Effect of Grafting on Growth, Yield, and Verticillium Wilt of Eggplant
Authors: Bletsos Fotios , Thanassoulopoulos Costas , Roupakias Demetrios
Published: February 2019

Eggplant (Solanum melongena L.) seedlings (`Tsakoniki') were grafted by hand on the Verticillium dahliae Kleb. resistant wild species Solanum torvum Sw. (GST) and Solanum sisymbriifolium Lam. (GSS). Grafted and nongrafted eggplants were transplanted to a fumigated soil with methyl bromide and to infested soil with microsclerotia of V. dahliae. Grafted plants were more vigorous, as measured by plant height, main stem diameter, and root system weight, than the nongrafted `Tsakoniki'. This resulted in an increased early production (GST, 45.5%; GSS, 18.4%) and late production (GST, 69.3%; GSS, 59.2%) as compared to the noninfected controls. The mean yield reduction (over years) in early production caused by the disease, as compared to the controls grown in fumigated soil, was 29.4%, 36.6%, and 77.9% for eggplant grafted on S. torvum, S. sisymbriifolium, and nongrafted plants, respectively. This yield reduction in total production was 6.9%, 20.5%, and 56.8%, respectively. The disease incidence in ungrafted plants was 96% and 100% during early and late harvest periods. In contrast, the disease incidence in grafted plants was significantly lower, averaging 28.1% (GST) and 52.6% (GSS) in early production, and 37.6% and 79.3%, respectively, in late production. Solanum torvum was found more resistant than S. sisymbriifolium, because grafted infected plants developed mild symptoms, as indicated by significantly lower leaf symptom index (average value 1.2 and 2.22) and disease index (average value 1.55 and 3.38), respectively. In conclusion, grafting of eggplant on either wild species had positive effects on growth, production, and verticillium wilt control.
Root Traits Play a Role in Integrated Management of Fusarium Root Rot in Snap Beans
Authors: Snapp S. , Kirk W. , Román-Avilés B. , Kelly J.
Published: February 2019

Fusarium root rot is a major limiting factor in snap bean (Phaseolus vulgaris L.) production. The level of genetic resistance in commercial bean cultivars is minimal and disease is frequently exacerbated by environmental factors. We investigated the contribution of vigorous, adventitious roots to enhancing root rot tolerance in snap bean. Seedling root system architecture was evaluated in 17 recombinant inbred lines (RILs) from a cross of a resistant snap bean line (FR266) and a susceptible dry bean cultivar (Montcalm). The RILs varied in tolerance to Fusarium root rot. Although overall length and branching density (as measured by fractal dimension and meristem numbers) of root systems were not related to root rot resistance, the lateral root number at the root: shoot interface was positively correlated with genotype tolerance (R2 = 0.6*). Root diameter was also positively correlated with tolerance; this is consistent with the hypothesis that larger adventitious and basal roots are beneficial under disease stress. A field-based study of commercial snap bean cultivars compared raised and flat-bed systems of production, in a soil inoculated with Fusarium solani f. sp. phaseoli. Substantially greater yields (40% to 90%) were observed in raised beds. Root vigor was relatively high (root length density >0.2 cm·cm−3) and root rot scores were lower with raised than with flat-beds, in 2001, but not in 2000. Overall, this is suggestive that integrated crop management practices can improve lateral root vigor and reduce root rot severity.
Pruning Severity Affects Yield, Berry Weight, and Hand Harvest Efficiency of Highbush Blueberry
Authors: Strik Bernadine , Buller Gil , Hellman Edward
Published: February 2019

The following pruning treatments were studied in mature `Bluecrop' (1996-2000) and `Berkeley' (1996-98) plants: 1) “conventional” pruning with removal of unproductive canes, thinning of 1-year-old shoots at the base of the bush, and removal of any unproductive wood or thinning of excessive fruiting wood near the top of the bush, as required; 2) “speed” pruning involving removal of one or two of the most unproductive canes at the base of the bush; and 3) “un-pruned” where no pruning was done for the length of this study. Conventional pruning took an average of 6.4 min/plot, while speed pruning saved 88.8% time. There was no pruning treatment effect on the percentage of fruit buds in `Berkeley' (42%) or `Bluecrop' (34%) or percent fruit set (70% to 90%, depending on cultivar and year) in any year. Un-pruned plants of both cultivars had significantly greater yield than conventionally pruned plants, depending on the year, while speed pruning generally resulted in intermediate yields. Un-pruned and speed-pruned plants produced berries that were 19% to 27% smaller than conventionally pruned plants, depending on year. The fruit harvest season of un-pruned plants began 3 to 5 days later and lasted a week longer than that of conventionally pruned plants. The harvest efficiency of un-pruned plants was reduced as much as 51% in the later years of this study and was most closely correlated with berry weight. Conventionally pruned plants had a significantly higher percentage of the above-ground dry weight allocated to 1-year-old wood and crown than un-pruned plants. In `Bluecrop', N concentration tended to be higher in the crown of conventionally pruned plants than in un-pruned or speed-pruned plants. Conventionally pruned `Bluecrop' plants had significantly higher concentrations of K and P and lower N than un-pruned plants and `Berkeley' had lower concentrations of N, than un-pruned plants. Results indicate that not pruning mature plants may be an option in the short-term, but may have undesirable effects for long-term sustainability.
Fruit Production of Berberis buxifolia Lam. in Tierra del Fuego
Authors: Arena M.E. , Vater G. , Peri P.
Published: February 2019

The aim of this work was to study the phenology and fruiting characteristics of B. buxifolia Lam. at Tierra del Fuego, Argentina. One-year-old shoots had significantly more and heavier fruit than older ones. The orientation, height position, and age of shoots significantly affected the shrub productivity. The highest relative number of fruiting shoots, fruit number and fruit weight were found on the northern side of shrub, followed by eastern, western and southern orientations. The relative number of fruiting shoots, fruit number and fruit weight were higher in the upper half of the plant. One-year-old fruiting shoots were significantly higher than 2- and 3-year-old shoots. Likewise, the relative fruit number and fruit weight were significantly higher on 1-year-old than older shoots.
Earliness and Yield of Tropical Winter Squash Improved by Transplants, Plastic Mulch, and Row Cover
Authors: Rulevich Matthew T. , Mangan Francis X. , Carter Anne K.
Published: February 2019

Field studies were conducted in 1998 and 1999 in Massachusetts to assess the effects of transplants, black polyethylene mulch, and polyester spun-bonded row cover on early fruit set and total yield of two squash (Cucurbita moschata Duchesne) cultivars: `C42 × La Segunda' calabaza and `Waltham' butternut. Treatment comparisons included direct-seeded or transplanted squash, with or without black polyethylene mulch, and with or without the addition of a row cover in all combinations. The use of transplants was more effective at stimulating early fruit set and highest total yield than the use of mulch and row cover. The initiation of fruit set using transplants was advanced 9 days relative to direct-seeding. Mulch and row cover treatments significantly advanced early fruit set by 7 and 5 days, respectively, but only in 1998. Yields for both winter squash were 45% higher using transplants compared to direct seeding, 19% higher using mulch compared to bare soil, and 16% higher using row cover compared to no row cover. Total yields were higher for both cultivars in 1999 (warm, dry season) than in 1998 (cool, wet season). Use of transplants with plastic and row cover compared to the use of direct seed with neither plastic nor row cover increased yield of calabaza by 100% in both 1998 and 1999. Only the direct seeded plus plastic plus row cover treatment had yields that were similar to any of the transplanted treatments. Transplant treatments also increased number of fruit per plant and fruit size for both calabaza and butternut.
Improved Drought Tolerance in Marigold by Manipulation of Root Growth with Buffered-phosphorus Nutrition
Authors: Borch Kristian , Miller Carter , Brown Kathleen M. , Lynch Jonathan P.
Published: February 2019

A series of experiments was conducted to investigate the response to drought stress of marigold (Tagetes patula L. `Janie Tangerine') plants grown with reduced phosphorus. Plants were grown with convention al phosphorus fertilization (1 mm, control) or one of two levels of alumina-buffered phosphorus (Al-P), 21 or 5 μm. Plants supplied with 21 μm Al-P produced plants with equal total dry weight, more flowers and reduced leaf area compared to control plants. Whole-plant photosynthetic CO2 assimilation expressed on a leaf area basis was nearly twice as high in 21 μm Al-P plants as in controls, probably as a result of reduced intraplant shading. In plants supplied with 21 μm Al-P, smaller leaf area resulted in reduced whole-plant transpiration. Moreover, the relative water content of the growing medium was significantly lower at wilting with 21 μm Al-P than for control or 5 μm Al-P regimes. The improved water acquisition with 21 μm Al-P could be explained by increased root proliferation via longer main roots and less densely distributed lateral roots. The results indicate that optimizing phosphorus nutrition with solid-phase buffered-phosphorus fertilizer improves drought tolerance by reducing transpiration and increasing water acquisition from the medium.
Evaluation of Captured Rainwater and Irrigation Runoff for Greenhouse Foliage and Bedding Plant Production
Authors: Chen Jianjun , Beeson Richard C. , Yeager Thomas H. , Stamps Robert H. , Felter Liz A.
Published: February 2019

Irrigation runoff water from a containerized landscape plant production bed was blended with rainwater from green house roofs in a constructed collection basin. Water from both the collection basin and an on-site potable well were characterized and used to grow foliage and bedding plants with overhead and ebb-and-flow irrigation systems. Over a 2-year period, a total of 18 foliage and 8 bedding plant cultivars were produced with plant growth and quality quantified. Alkalinity, electrical conductivity, hardness, and concentrations of nutrients of water from both sources were well within desired levels for greenhouse crop production. Turbidity and pH were relatively high from algal growth in the collection basin. However, substrate pH, irrigated by either water source, remained between 6 and 7 throughout the production periods. All plants at the time of finishing were of marketable sizes and salable quality independent of water source. No disease incidences or growth disorders related to water sources were observed. Results suggest that captured irrigation runoff blended with rainwater can be an alternative water source for green house crop production.
Soybean Oil as a Summer Spray for Apple: European Red Mite Control, Net CO2 Assimilation, and Phytotoxicity
Authors: Moran Renae E. , Deyton Dennis E. , Sams Carl E. , Pless Charles D. , Cummins John C.
Published: February 2019

Soybean [Glycine max (L.) Merrill] oil was applied to apple trees [Malus sylvestris (L.) Mill var. domestica (Borkh.) Mansf.] as a summer spray in six studies to determine if it controls European red mites [Panonychus ulmi (Koch.)], how it affects net CO2 assimilation (A), and if it causes phytotoxicity. Sprays of 0.5%, 1.0%, and 1.5% soybean oil {TNsoy1 formulation [soybean oil premixed with Latron B-1956 (LAT) spreader-sticker at 10 oil: 1 LAT (v/v)]} reduced mite populations by 94%. Sprays of 1% and 2% soybean oil reduced mite populations to three and four mites per leaf, respectively, compared to 25 per leaf on water-sprayed plants. Soybean oil concentrations of 1.0% and 1.5% applied to whole trees reduced A for less than 7 days. Phytotoxicity did not occur when soybean oil was applied with an airblast sprayer at concentrations of 1.0% and 1.5% or with a mist bottle at 2%. Phytotoxicity occurred when soybean oil was applied with a mist bottle at 4% and 6%, which left soybean oil leaf residues of 0.22 to 0.50 mg·cm-2. No phytotoxicity occurred with 4% SunSpray, which resulted in a mean leaf residue of only 0.13 mg·cm-2. Spraying 1% soybean oil tended to give better mite control than 1% SunSpray Ultra-Fine oil, but caused greater oil residues and a greater reduction in A.
Fungal Ecology of Strawberry Flower Anthers and the Saprobic Role of Cladosporium cladosporioides in Relation to Fruit Deformity Problems
Authors: Koike Steven T. , Vilchez Miguel S. , Paulus Albert O.
Published: February 2019

California has an extensive strawberry (Fragaria ×ananassa L.) industry that has built its reputation on the production of large volumes of fruit that are evenly and fully developed. While some fruit deformity occurs every year, in various counties during the 1997-2000 seasons there were higher than usual numbers of uneven or “catfaced” strawberry fruit. It was thought that the presence of the fungus Cladosporium cladosporioides (Fresen.) G.A. De Vries on flower anthers may have interfered with pollination and increased cull rates. We collected and incubated flower anthers to determine the fungal populations on such tissue and found that C. cladosporioides accounted for the majority of the culturable fungal colonies present. However, while 100% of a flower's anthers were colonized with C. cladosporioides after spray inoculations, the incidence and severity of malformed fruit were not significantly different from untreated flowers. Physically removing all anthers shortly after anthesis likewise did not result in significant differences in fruit quality when compared to untreated control flowers. We conclude that C. cladosporioides colonization of flower anthers has a minimal impact on fruit quality under most field conditions.
Molecular Genetic Diversity Among 12 Clones of Lagerstroemia fauriei Revealed by AFLP and RAPD Markers
Authors: Pooler Margaret R.
Published: February 2019

Many popular crapemyrtle (Lagerstroemia L.) cultivars grown in the United States are interspecific hybrids between L. indica L. and L. fauriei Koehne. The 22 hybrid cultivars released from the U.S. National Arboretum contain primarily genetic material from L. fauriei PI 237884. Examining the genetic diversity ofL. fauriei specimens in the U.S. is valuable because of the historical and economic significance of the species, the increasing interest it is receiving as a source of new cultivars, and its threatened status in the wild. Our objectives were to examine molecular genetic diversity among L. fauriei accessions using Randomly Amplified Polymorphic DNA (RAPD) and Amplified Fragment Length Polymorphisms (AFLP) markers. Our results indicate: 1) RAPD and AFLP markers are generally consistent in the genetic relationships that they suggest; 2) the L. fauriei germplasm we examined falls into at least three distinct clusters; and 3) the genetic base of cultivated Lagerstroemia could be broadened significantly by incorporating some of this more diverse L. fauriei germplasm into breeding programs.
Effects of Pruning and Cropping on Field-grown Primocane-fruiting Blackberries
Authors: Drake Chrislyn A. , Clark John R.
Published: February 2019

Primocane-fruiting blackberry (Rubus subgenus Rubus Watson) selections have recently been developed by the University of Arkansas, but proper cane-management practices for the new germplasm have not yet been determined. It was observed in previous trials that primocane-fruiting selections flowered and fruited in late July and early August in Arkansas, which is often the hottest part of the summer and earlier than desired. Therefore, this study was conducted to determine the effects of primocane tipping on cane and fruit characteristics and to determine the effect of floricane presence on primocane performance. In Fayetteville, one-year-old plants of selections APF-8 and APF-12 were used to apply the four primocane-tipping treatments in combination with the two cane management treatments (presence or absence of floricanes). In Clarksville, the same genotypes were used to apply the two cane management treatments (presence or absence of floricanes). The tipping treatments had a significant effect on primocane yield and peak harvest as well as other parameters. The cane management treatments had a significant effect on total yield, but no other effects.
Screening for Aspergillus flavus Resistance in Almond
Authors: Dicenta F. , Martínez-Gómez P. , Martínez-Pato E. , Gradziel T.M.
Published: February 2019

Aspergillus flavus Link. is a filamentous fungus affecting almond [Prunus dulcis (Mill.) D.A. Webb] kernels in the field and during storage. This fungus can produce afla-toxins (carcinogenic and immunosuppressive mycotoxins), which prevent the marketability of almond kernels. Aspergillus flavus resistance has not been an objective in conventional almond breeding programs. Because the importance of this disease is increasing, evaluations of cultivar susceptibility are being performed. In this study, the screening for A. flavus resistance in 40 almond genotypes has been carried out in controlled inoculation conditions at 26 °C. Eighteen days after the inoculation, kernels of all the almond cultivars assayed showed susceptibility to A. flavus. Nevertheless, differences among cultivars in the percentage of kernel surface colonized by the fungus were observed. The Spanish cultivar Ramillette was the least susceptible. Susceptibility was not related to the geographic origin of the cultivar.
Genetic Diversity in Black Raspberry Detected by RAPD Markers
Authors: Weber C.A.
Published: February 2019

Lack of variation among black raspberry cultivars is thought to be a limiting factor in fruit production and in breeding improved cultivars. An assessment of the available diversity in black raspberry is needed to effectively develop improved cultivars. Such an assessment was done to estimate the genetic similarities for RAPD markers in 16 black raspberry genotypes and to determine the genetic diversity among these genotypes based on these markers. In addition, the ability to distinguish between the black raspberry genotypes, two red raspberry cultivars (Rubus idaeus L.), and a blackberry cultivar (Rubus hybrid) was determined. A similarity matrix from 379 RAPD markers was calculated, and a phylogenetic tree was constructed using the PHYLIP suite of phylogeny software, which revealed the relationship among the genotypes. An average of 81% similarity was calculated among 16 black raspberry genotypes with a maximum similarity of 98% and a minimum of 70%. The average similarity between black raspberry and red raspberry was 41% and was 26% between black raspberry and blackberry. Combined marker profiles from six RAPD primers could be used to distinguish between the 16 black raspberry genotypes. Red raspberry and blackberry could be distinguished from black raspberry by 27 and 29 of 30 RAPD primers tested, respectively. Genetic diversity was most prominent in genotypes from the extremes of the black raspberry indigenous range. Diversifying the germplasm pool for black raspberry cultivar improvement can be achieved through utilizing genotypes from the extremes of the black raspberry range and through interspecific hybridization.
Rootstock Affects Yield, Yield Efficiency, and Harvest Rate of 'Kensington Pride' Mango
Authors: Smith Malcolm W. , Hoult Mark D. , Bright Jeremy D.
Published: February 2019

Low yields and high harvesting costs are long-standing problems in mango (Mangifera indica L.) cultivation. In an effort to increase productivity in the scion 'Kensington Pride' we examined the impact of nine different rootstocks over a 10-year period. Rootstock effects on fruit production were significant in most seasons, and cumulative yields (nine seasons of cropping) for the best treatment ('Sg. Siput') exceeded those of the poorest treatment ('Sabre') by 141%. Yield efficiencies (expressed on both a trunk cross-sectional area and canopy silhouette area basis) were also significantly affected by rootstock. Rootstock effects on yield and yield efficiency were generally consistent across seasons, despite large seasonal variations in yield. Harvest rates were also influenced by rootstock, and were poorly correlated with tree size. These results demonstrate possibilities for manipulating mango scion productivity through rootstock genotype.
Transformation of a Strawberry Cultivar Using a Modified Regeneration Medium
Authors: Ricardo Vellicce Gabriel , Coll Yamilet , Castagnaro Atilio , Ricci Juan Carlos Diaz
Published: February 2019

A protocol for shoot regeneration of strawberry (Fragaria ×ananassa Duch. `Pajaro') leaf disks was developed. In Murashige and Skoog basal medium with 3% of sucrose (w/v), BA (1 mg·L-1), and 2,4-D (0.1 mg·L-1), 70% of the cultivated leaf explants regenerated plants. This regeneration system was used for genetic transformation of strawberry with Agrobacterium tumefaciens strain LBA 4404 carrying the binary vector plasmid pBI121 that contains the npt II (neomycin phosphotransferase) and uidA (ß-D glucuronidase) genes. A transformation rate of 6.6%, calculated as the number of leaf disks able to regenerate kanamycin-resistant plants/total leaf disks infected, was obtained. The integration of both marker genes was evaluated in each transformed line by PCR (polymerase chain reaction) amplification of the npt II and uidA genes. High expression levels of the uidA gene were found in leaves, flower, and fruits of the transgenic lines. The protocol here reported may represent a way to conduct transformation research in strawberries. Chemical names used: benzyladenine (BA); 2,4-dichlorophenoxyacetic acid (2,4-D).
Cold Tolerance in 'Kousui' Japanese Pear and Possibility for Avoiding Frost Injury by Treatment with n-Propyl Dihydrojasmonate
Authors: Sekozawa Yoshihiko , Sugaya Sumiko , Gemma Hiroshi , Iwahori Shuichi
Published: February 2019

Effects of n-propyl dihydrojasmonate (PDJ) treatment on flowers of Japanese pear 'Kousui' (Pyrus pyrifolia Nakai cv. Kousui) during spring frost were investigated to study mechanisms for avoiding spring frost injury. PDJ applied during the flowering period resulted in a lower injury index for the ovules and pistils after freezing tests. Average ion leakage in control flowers was 37.9% during the balloon stage at -5 °C, while the flowers treated with PDJ displayed a 16.6% ion leakage. Similarly, at the full bloom stage, PDJ treatment reduced ion leakage at -5 °C from 73.1% to 47.8% in the control. The organs of the flower more sensitive to low temperature stress were the ovule, pistil, and ovary; stamens were more resistant. Sugar content in the flower at the balloon stage was increased by PDJ when treated at the pink stage. Moreover, free amino acids, especially proline, increased similarly with PDJ treatment. These results show that PDJ affects supercooling capacity of a flower by changing solute content and protects organs from freezing.
Prohexadione-Ca and Ethephon Reduce Shoot Growth and Increase Flowering in Young, Vigorous Sweet Cherry Trees
Authors: Elfving Don C. , Lang Gregory A. , Visser Dwayne B.
Published: February 2019

Prohexadione-Ca (P-Ca) and ethephon (ETH) were evaluated as potential inhibitors of growth and promoters of early flowering for high density orchard management of sweet cherry (Prunus avium L.) trees on vigorous rootstocks. Single applications (P-Ca at 125 to 250 mg·L-1 active ingredient (a.i.) or ETH at 175 to 200 mg·L-1 a.i.) to young, nonfruiting sweet cherry trees produced short-term, generally transient reductions in terminal shoot elongation, and did not stimulate flower bud formation. Tank-mix applications (P-Ca + ETH) usually produced a stronger, possibly synergistic, reduction in shoot growth rate. Single tank-mix applications either increased subsequent flower bud density on previous season shoots or had no effect; when a second application was made three weeks later to the same trees, subsequent flower bud density on previous season shoots and spurs on older wood increased ≈3-fold over untreated trees. Yield efficiency (g·cm2 trunk cross-sectional area) also increased nearly 3-fold. Chemical names used: (2-chloroethyl) phosphonic acid (ethephon); calcium 3-oxido-4-propionyl-5-oxo-3-cyclohexene carboxylate (prohexadione-Ca); polyoxyethylene polypropoxypropanol, dihydroxypropane, 2-butoxyethanol (Regulaid); aliphatic polycarboxylate, calcium (Tri-Fol).