bluuebunny/crossref_metadata_2025 huggingface dataset:
Candelilla-shellac: An Alternative Formulation for Coating Apples
Authors: Alleyne Victorine , Hagenmaier Robert D.
Published: February 2019

An experimental candelilla-shellac formulation for coating apples (Malus ×domestica Borkh.) was developed and compared with commercial shellac-based and carnauba-shellac-based coatings on `Gala' and `Delicious' apples by determining effects on quality attributes, respiration, and internal atmospheres. Fruit were stored at 5 °C for 7 days followed by storage at 21 °C for 14 days. Gloss of `Delicious' apples coated with candelilla-shellac formulations containing 7% to 34% shellac increased with increasing shellac concentrations. `Gala' and `Delicious' apples coated with a candelilla formulation containing 34% shellac maintained quality similar to those coated with commercial carnauba-shellac-based coatings, as indicated by gloss, firmness, internal CO2, O2 and ethanol levels, steady-state respiration rate, weight loss, and flavor. By comparison, shellac-coated fruit maintained the highest gloss throughout the experimental period. Shellac-coated apples were also firmer, contained more ethanol, and received higher flavor scores than did apples receiving other coating treatments. Gloss of all coated fruit decreased with time, although shellac-coated fruit lost less gloss over the 21-day storage period. Analysis of gloss, firmness, fruit respiration, ethanol, weight loss, and flavor demonstrate that the candelilla formulation containing 34% shellac is competitive with current commercial carnauba-based apple-coating products.
Transgenic Resistance to the Colorado Potato Beetle in Bt-expressing Eggplant Fields
Authors: Acciarri Nazareno , Vitelli Gabriele , Arpaia Salvatore , Mennella Giuseppe , Sunseri Francesco , Rotino Giuseppe L.
Published: February 2019

Colorado potato beetle (CPB; Leptinotarsa decemlineata-Say) is a serious pest because it has developed resistance against insecticides. Three transgenic eggplant (Solanum melongena L.) lines bearing a mutagenized Bacillus thuringiensis Berl. gene coding for the Cry3B toxin, and the nontransformed control DR2-line were tested in field trials to assess their insect resistance. The transgenic lines 3-2, 6-1, and 9-8 were tested at two different locations in a randomized complete-block design. Samples were taken biweekly to assess the level of CPB and the presence of other insects. At harvest, total yield and fruit number per plot were recorded. Two transgenic lines showed high levels of resistance at both locations, as measured by CPB abundance and yield. Fruit production was almost twice as great in the highly resistant lines (3-2 and 9-8) as in the nontransformed control. The 6-1 transgenic line showed an intermediate level of resistance; it was similar to the control under heavy CPB pressure and was comparable to the other transgenic lines under milder infestations. Analysis by double antibody sandwich–enzyme linked immunosorbent assay (DAS–ELISA), performed on different tissues, revealed a lower amount of Cry3B protein in the 6-1 transgenic line than in lines 3-2 and 9-8. No detrimental effects on nontarget arthropods (including the chrysomelid Altica) were evident. Field observations confirmed that Bt may be able to control CPB infestation in eggplant, representing a potential effective and environmentally safe means of pest control.
Field Performance of `Sanna' Lingonberry Derived by Micropropagation vs. Stem Cuttings
Authors: Gustavsson Björn A. , Stanys Vidmantas
Published: February 2019

Field performance in lingonberry (Vaccinium vitis-idaea L. cv. Sanna) was compared in 1995–97 for plants produced by tissue culture (TC) vs. stem cuttings (SC). Pot plants of about the same size were transplanted from the nursery to an infertile, sandy moraine soil. Survival was 97% for the TC plants but only 83% for the SC plants. Fruit yield was significantly greater for TC plants than for SC plants in both the second (+79%) and third (+190%) years, but mean fruit weight was not influenced by propagation method. Rhizome production and total plant weight were also greater for the TC plants. Although micropropagation may give rise to somaclonal variation, no obviously variant plants were apparent in the field.
Interaction between Explant Size and Cultivar Affects Shoot Organogenic Competence of Watermelon Cotyledons
Authors: Compton Michael E.
Published: February 2019

Organic competence of different explant sizes and locations on watermelon seedlings was determined by calculating the percentage of cotyledon explants that produced adventitious shoots. About 52% (214/412) of explants prepared from the proximal region of cotyledons formed shoots, whereas only ≈6% (24/411) of distal explants did so. Shoot formation was limited to the proximal end of basal explants but was not restricted to any specific region on distal ones. The percentage of explants that produced harvestable shoots was greater from basal halves than basal quarters in `Sweet Gem', `Crimson Sweet', and `Minilee', but explant size did not affect adventitious shoot regeneration of `Yellow Doll', resulting in significant interaction between cultivar and explant size. This study indicates that cultivars that respond poorly to in vitro procedures may have fewer cells competent for shoot regeneration, requiring special care during explant preparation.
Using a Chlorophyll Meter to Determine the Chlorophyll Concentration, Nitrogen Concentration, and Visual Quality of St. Augustinegrass
Authors: Rodriguez Ian R. , Miller Grady L.
Published: February 2019

Because high rates of nitrogen fertility are necessary for producing high-quality turfgrasses, quick, reliable methods of determining the N status of turfgrasses would be valuable management tools. The objective of this study was to evaluate the capacity of a hand-held chlorophyll meter (SPAD-502) to provide a relative index of chlorophyll concentrations, N concentrations, and visual quality in St. Augustinegrass [Stenotaphrum secondatum (Walt.) Kuntze]. Two experiments were conducted in a greenhouse in 1998 to evaluate the utility of SPAD readings. Established pots of `Floratam' were subjected to weekly foliar Fe treatments at Fe rates of 0 and 0.17 kg·ha–1 for 4 weeks. Six weekly nitrogen fertilizer treatments were applied in the form of ammonium sulfate at N rates of 0, 5.75, 11.5, 17.25, and 23 kg·ha–1 for 4 weeks. Greenhouse SPAD readings were not affected by Fe treatment, but N treatments resulted in differences in SPAD readings, visual quality, and chlorophyll concentrations. The readings were positively correlated with chlorophyll concentrations (r2 = 0.79), visual ratings (r2 = 0.74), and total Kjeldahl nitrogen (TKN) (r2 = 0.71). Readings taken from field-grown `Floratam', `Floratine', and `Floralawn' St. Augustinegrass were poorly correlated (r2 < 0.63) with chlorophyll concentrations and TKN. Unless future techniques improve dependability of the SPAD meter under field conditions for measuring chlorophyll and N concentration of a stand of turfgrass, the usefulness of such readings for the management of St. Augustinegrass seems limited.
Mowing Height and Nitrogen Rate Affect Turf Quality and Vegetative Growth of Common Carpetgrass
Authors: Bush Edward W. , Owings Allen D. , Shepard Dennis P. , McCrimmon James N.
Published: February 2019

Common carpetgrass (Axonopus affinis Chase), mowed at 3.8 or 7.6 cm and fertilized with at least 98 kg·ha–1 N, maintained acceptable lawngrass quality during the 1993 and 1994 growing seasons. Cumulative vegetative growth (CVG) quality and coverage were increased in mowed plots fertilized with 98, 147, or 196 kg·ha–1 N. Unsightly seedheads were a problem in nonmowed plots 3 weeks after the start of the experiment, but did not appear in the mowed plots. Our results indicate that mowing common carpetgrass at 3.8 or 7.6 cm and fertilizing with 98, 147, or 196 kg·ha–1 N will provide acceptable turfgrass quality.
Gas Exchange and Growth of Two Transplanted, Field-grown Tree Species in an Arid Climate
Authors: Montague Thayne , Kjelgren Roger , Rupp Larry
Published: February 2019

Gas exchange and growth of transplanted and nontransplanted, field-grown Norway maple (Acer platanoides L. `Schwedleri') and littleleaf linden (Tilia cordata Mill. `Greenspire') trees were investigated in an arid climate. In the spring of 1995, three trees of each species were moved with a tree spade to a new location within a field nursery and three nontransplanted trees were selected as controls. Predawn leaf water potential, morning-to-evening stomatal conductance and leaf temperature, leaf-to-air vapor pressure difference, midday stomatal conductance and photosynthetic rate, and growth data were collected over a 2-year period. After transplanting, weekly predawn leaf water potential indicated that transplanted trees were under greater water stress than were nontransplanted (control) trees. However, predawn leaf water potential of maple trees recovered to control levels 18 weeks after transplanting, while that of transplanted linden trees remained more negative than that of controls. In 1995, stomatal conductance and photosynthetic rates were lower throughout the day for transplanted trees. In 1996, gas exchange rates of transplanted maple trees recovered to near control levels while rates for transplanted linden trees did not. Sensitivity of stomata to leaf-to-air vapor pressure difference varied with species and with transplant treatment. Each year transplanted trees of both species had less apical growth than did control trees. Although gas exchange and apical growth of transplanted trees was reduced following transplanting, recovery of gas exchange to control rates differed with species.
Performance Evaluation of Fine Fescue Turfgrass Cultivars in Maine
Authors: Pennucci Annamarie , Langille Alan R.
Published: February 2019

The N.T.E.P. fine fescue test was established in Sept. 1994 in the Turfgrass Experimental Plot Area of the Littlefield Ornamental Trial Garden on the Univ. of Maine campus. The test consisted of 59 cultivars seeded in a randomized complete-block design with three replications. Following soil preparation, the Marlowe fine sandy soil was amended with lime and starter fertilizer according to soil test recommendations. Seeding was facilitated using a 5 × 3-ft plywood box to eliminate wind drift, and seed was raked in by hand. The study was conducted in a shade-free location with a maintenance fertility program of N at 0.6 lb/1000 ft2 per month of growing season using a slow-release commercial 20-5-15 fertilizer. Supplemental moisture was supplied as needed using an in-ground irrigation system. Mowing was initiated in May 1995 at a height of 2.5 inches and reduced to maintenance height of 2 inches for the duration of the 3-year test. Visual turf quality, turf density, color, weediness, and disease ratings were made monthly during each growing season and were statistically analyzed. Cultivars Darwin, NJ F-93, Columbra, Florentine, and the Banner II and III series were ranked as the best performers in the early- and late-season evaluations. BARFRR4ZBD, Jasper, Defiant, Silverlawn, Treazure, SR 5100, and Spartan were cultivars that performed well in early summer; however, during August, all cultivars showed depressed quality scores and no differences were observed. With the onset of true autumn conditions in October, the number of excellent performing cultivars approximated the same number observed in the spring. These results confirm that a number of fineleaf fescue cultivars are now available whose performance begins to rival Kentucky bluegrass under Maine conditions and will certainly provide better long-term turf than will perennial ryegrass.
Host Range of a Select Isolate of the Beneficial Ericoid Mycorrhizal Fungus Hymenoscyphus ericae
Authors: Gorman Nicole R. , Starrett Mark C.
Published: February 2019

Studies were conducted to examine the host range of a select isolate of the ericoid mycorrhizal fungus, Hymenoscyphus ericae (Read) Korf and Kernan [American Type Culture Collection (ATCC) #32985]. Host status was tested for 15 ericaceous species, including Calluna vulgaris, Enkianthus campanulatus, Gaultheria procumbens, Kalmia latifolia, Leucothoe fontanesiana, Oxydendrum arboreum, Pieris floribunda, Rhododendron calendulaceum, Rhododendron carolinianum, Rhododendron catawbiense, Rhododendron maximum, Rhododendron mucronulatum, Vaccinium corymbosum, and Vaccinium macrocarpon. Arbutus unedo, an ericaceous species that forms arbutoid, not ericoid, mycorrhizae was used as a negative control. All of the species were colonized by the ericoid isolate with the exception of Enkianthus campanulatus and the negative control. The benefits of the association and possible commercial applications are discussed.
Correcting Lowbush Blueberry Boron Deficiency with Soil or Foliar Application
Authors: Smagula J.M. , Litten W. , Dunham S.
Published: February 2019

In the acid podzol soils of Maine where most lowbush blueberries are grown, low availability of boron tends to keep foliar B concentration below the 24 ppm standard. To compare efficacy of soil and foliar boron application methods, 1.5 × 7.6-m treatment plots in a commer-cial lowbush blueberry field received soil-applied borate at 0, 1.1, 2.2, or 3.3 kg·ha-1 B with or without additional DAP (89 kg·ha-1 P) and ZnSO4 (3.3 kg·ha-1 Zn) or foliar-applied Solubor at 0, 0.24, 0.49, or 0.74 kg·ha-1 B with or without the additional DAP and Zn. These 16 treatments were replicated eight times in a randomized complete-block design. Leaf B concentrations were raised by all soil-applied borate treatments and by the 0.49 and 0.74 kg·ha-1 B foliar Solubor treatments, compared to the controls. When borate at 2.2 or 3.3 kg·ha-1 B was combined with DAP plus Zn a lower leaf B concentration was observed compared to B alone, possibly due to a dilution effect caused by an increase in DAP-induced growth. Leaf P deficiency (<0.125% P) was corrected when DAP and Zn were included in the fertilizer treatment. The greatest potential yield (flower buds/stem and flower bud density) was measured in treatment plots receiving a combination of DAP plus Zn and either borate at 2.2 kg·ha-1 B or Solubor at 0.74 kg·ha-1 B. With no additional treatments applied in 1999, leaf B concentrations were slightly higher in soil-treated and foliar-treated plots than in controls suggesting a small carryover from 1997-applied boron. Carryover may vary with rainfall.
Carbon Dioxide Effects on Metabolism of Two Apple Fruit Cultivars
Authors: Watkins Chris B. , Fernández-Trujillo Juan-Pablo , Nock Jacqueline F.
Published: February 2019

Susceptibility of apple fruit to CO2 can be affected by cultivar and postharvest treatment with diphenylamine (DPA). To study possible metabolic reasons for CO2 injury development, `Cortland' and `Law Rome' apple fruit were either untreated or treated with DPA at harvest, and then exposed to air or 45 kPa CO2 for up to 12 days. Fruit were sampled at 3-day intervals during treatment, and peel and flesh samples were taken for organic acid and fermentation product analysis. Additional fruit were removed to air and stored for 25 weeks for evaluation of injury. `Cortland' apple fruit had more external CO2 injury, but less internal CO2 injury than `Law Rome'. DPA treatment markedly reduced incidence of both external and internal injury. Fermentation products increased in peel and flesh of both cultivars with increasing exposure to CO2. However, acetaldehyde concentrations were ≈10 times higher in peel and flesh of `Law Rome' than `Cortland' apples. Ethanol concentrations in the flesh were similar in both cultivars, but were about twice as high in `Cortland' than `Law Rome' peel. Neither acetaldehyde nor ethanol concentrations were affected consistently by DPA treatment. Cultivar or DPA treatment did not affect accumulation of succinate, often regarded as the compound responsible for CO2 injury. These results do not indicate that acetaldehyde, ethanol, or succinate accumulation is responsible for CO2 injury in apple fruit.
Determination of the Optimal Fertilizer Concentration Range for Plant Growth in a Peat-based Medium
Authors: Mills Gretchen E. , Barker Allen V.
Published: February 2019

For optimum plant growth in containers, adequate plant nutrition is essential. Objectives of this research were to determine the optimum fertilization of tomatoes (Lycopersicon esculentum Mill.) in a peatbased medium and to assess plant nutrition by plant and media analysis. Tomato seedlings ('Heinz 1437') were transplanted (one plant per pot) into 2-L pots filled with a peat-based medium. The medium was fertilized with a progressive array of soluble fertilizers to supply N at 0, 50, 100, 150, or 200 mg·L-1 of solution with concomitant proportional increases of other macronutrients with each increase in N (P at 0, 10, 20, 30, or 40; K at 0, 40, 80, 120, or 160; Ca at 0, 50, 100, 150, or 200; and Mg at 0, 12, 24, 36, or 48 mg·L-1). The plants were irrigated starting with 100 mL fertilizer solution per day and increasing to 200 mL per day as plant growth progressed. The tomatoes were harvested at three stages of growth (five-leaf stage, flower initiation, and fruit initiation) for analysis of growth and composition. Samples of media for nutrient analysis were taken at each growth stage. Plant biomass increased linearly as fertilizer level increased or as time progressed. Generally, concentrations of nutrients in the medium increased linearly with increases in nutrients in the solutions. With time, N concentrations in media rose, but P, K, Ca, and Mg in the media fell. Concentrations of N, P, or K in leaves increased as nutrition increased, but Mg or Ca in leaves had no significant changes with increased nutrient supply. The N, P, Ca, and Mg in tissues fell, but K rose with time. Assessment of plant nutrition was best at flower initiation, with assessments at the other stages of development being judged as untimely or excessively variable. For optimum growth, critical concentrations of nutrients in the media (mg·kg-1) at flower initiation were judged to be 30 NO3-N, 30 P, 300 K, 2600 Ca, and 800 Mg and in leaves (g·kg-1) to be 35 N, 10 P, 70 K, 35 Ca, and 20 Mg. Optimum fertilization to reach these critical concentrations was reached with the third level (the regime with 100 mg N/L) or higher levels of nutrition.
Plant Density and Inter-row Polyethylene Mulch Treatment Affect Growth and Yield of Tomato
Authors: Ouellette Amy , Loy J. Brent
Published: February 2019

A field study was conducted to compare the effect of different planting densities and polyethylene mulch treatments on growth and yield of `Mountain Fresh' trellised tomato grown on raised beds on 1.8-m centers. The experiment design was a split plot with four replications and four mulch treatments as main effects: 1) standard black mulch (B), 2) Sonoco red mulch (R), 3) black mulch with interrow (between beds) reflective white on black mulch (B/W), and 4) red mulch with inter-row R/W. Subtreatments were three within-row spacings: 1) 0.60 m (8966 plants/ha); 2) 0.45 m (11955 plants/ha; standard spacing), and 3) 0.30 m (17932 plants/ha). Yield was determined from eight-plant plots and adjacent plants were harvested at regular intervals to determine plant biomass accumulation and partitioning of biomass among roots, stems, leaves, and reproductive organs. There was a linear increase in yield among mulch treatments with increasing plant density. The B/W mulch treatment increased midseason and total yields ≈20% over that of the other mulch treatments. Fruit yield of plants with the B/W mulch treatment at the 0.3-m spacing was 54% higher (151 MT/ha) than that of plants grown on black mulch with the standard plant spacing of 0.45 m (97.9 MT/ha). There was a linear decrease in fruit size with increasing plant density; however, plants grown at the 0.30-m spacing on the B/W mulched plots exhibited only a 2.7% decrease in fruit size as compared to plants grown at the standard 0.45-m spacing on black mulch.
Chilling Injury of Chile Peppers (Capsicum annuum L.)
Authors: Sullivan Kathleen M. , Bramlage William J.
Published: February 2019

Seven types of chile peppers were tested for differences in susceptibility to postharvest chilling injury (CI). Cherry, cubanelle, Hungarian wax (HW), poblano, serrano, and both mature-green and full-color (red) jalapeño fruit were stored at 2.5, 7, and 15 °C for 0 to 30 days. External C2H4 production at 12 and 24 hours after removal from storage and internal C2H4 concentration at 24 hours were measured. There was no significant difference in C2H4 production after the first 12 hours, but serrano produced significantly less C2H4 than the other types during the second 12 hours. Among the cultivars there were differences in the amounts of internal C2H4 measured: HW had the highest levels measured, and serrano had undetectable levels. CI has been observed on bell and some chile pepper cultivars as small black pits, and the recommended nonchilling storage temperature is 7 °C for all peppers. In this study, scald (a surface browning) was observed on HW and cubanelle fruit in addition to pitting, which occurred on all the cultivars. Susceptibility to chilling varied among pepper types in this study. HW peppers were the most susceptible, manifesting scald after 4 days at 2.5 °C and scald and pits after 16 days at 7 °C. Serrano fruit were the most resistant to CI, only pitting after 23 days at 2.5 °C, and having no symptoms after storage at 7 °C for 30 days. Cherry and poblano peppers developed pits after 8 days at 2.5 °C. Both green and red jalapeños pitted after 12 days at 2.5 °C, and cubanelles had scald after 16 days at 2.5 °C. Poblano fruit had large, deep pits after 8 days at 7 °C, cherry peppers pitted after 12 days, and both green and red jalapeño fruit pitted after 16 days at 7 °C. Both pits and scald were observed on cubanelle fruit after 23 days at 7 °C. Recommendations for storage of peppers should be expanded to accommodate differences among cultivars.
Biomass Partitioning and Seed Yield in Hybrid Snackseed Pumpkins
Authors: Chretien Robert L. , Loy J. Brent
Published: February 2019

A field study was conducted to compare seed yield and fruit biomass partitioning among 11 F1 hybrid snackseed (hull-less seeded) pumpkins. Experimental plots were seeded on 3 June 1999, using a randomized complete-block design with four replications and 20 plants per plot. Rows were spaced 1.8 m apart; within-row spacing was 0.3 m. The plots were divided in half with 10 plants for fruit and seed yield determinations and 10 plants for fruit biomass partitioning studies. Seed yields among hybrids ranged from 818 kg·ha-1 for NH1003 to 1575 kg·ha-1 for NH1041. The three highest-yielding hybrids (NH1030, NH1040, and NH1041) were derived from sister lines crossed to a common parent and were characterized by small fruit size (0.8 to 1.4 kg) and high seed biomass per kilogram of fruit fresh weight. The next highest-yielding group of hybrids (NH1024, NH1043, NH1044, and NH1045) also had small fruit, and two pairs of hybrids, NH1024/NH1043 and NH1044/NH1045, each shared a common parent. The four lowest-yielding hybrids (NH1003, NH1025, NH1027, and NH1029) were characterized by larger fruit (2 to 3 kg) and low seed yield per kilogram fruit fresh weight, but had larger seeds (average between 175 to 183 mg) than the other hybrids (130 to 165 mg). Peak percent dry matter of mesocarp tissue at 35 days postanthesis (PA) was lowest in large-fruited hybrids and highest in the highest-yielding hybrids. In most hybrids, percent dry matter decreased between 35 days PA and fruit maturity (65 days PA), indicating a shortage of photosythates needed for maintaining mesocarp biomass and maximizing seed fill. The highest-yielding varieties partitioned a greater portion of fruit biomass into seeds rather than flesh. Seed yield per plot was highly correlated with seed yield per kilogram of fruit fresh weight.
Characterization of Nitrate Uptake by Kentucky Bluegrass at the Whole-plant and Organ Levels
Authors: Wang Yuexia , Basu Chhandak , Jiang Zhongchun , Sullivan W. Michael
Published: February 2019

It has been suggested that shoot demand for nitrogen controls nitrate uptake in plant roots. In turfgrasses, shoots are partly removed by regular mowing, which may severely alter nitrate uptake ability. However, reported groundwater nitrate concentrations under intensively managed turf are well below the USEPA maximum contaminant limit of 10 mg·L-1 nitrate-N in potable water. We hypothesize that the turfgrass root can also exert significant control over its nitrate uptake ability. The present study was to test this hypothesis by comparing nitrate uptake rates of excised roots and intact, whole plants of six Kentucky bluegrass (Poa pratensis L.) cultivars. Three replications or cultures of each cultivar were grown in sand for 15 months. For whole-plant nitrate uptake, the roots were placed in a flask filled with 200 mL of a nutrient solution containing 0.125 mm nitrate. Nitrate depletion was monitored at 20-minute intervals over an 8-hour period under ≈600 μmol·m-2·s-1 photosynthetic photon flux density. After the whole-plant experiment, the plants were placed in an N-free nutrient solution for 15 hours, and the roots were then excised. The excised roots were placed in a beaker containing 60 mL of the 0.125-mm nitrate nutrient solution and nitrate depletion was monitored at 20-minute intervals over a 6-hour period. Whole-plant nitrate uptake rate differed significantly (P ≤ 0.05) among cultivars and was twice that of excised roots. Excised root nitrate uptake rate exhibited no cultivar difference but was positively and significantly (P ≤ 0.05) correlated with whole-plant nitrate uptake rate. Our results indicate that turfgrass roots exert substantial control over nitrate uptake.
Changes in Essential Elements Levels during Flower Development
Authors: Verlinden Sven
Published: February 2019

Flower senescence in many plants is associated with a significant increase in ethylene production. This ethylene has been shown to play a regulatory role in the demise of the petals. The regulation of petal senescence by ethylene is thought to facilitate the ordered breakdown and remobilization of cellular constituents to other plant and flower organs. In order to gain insight in the remobilization of cellular constituents, we investigated changes in P, Ca, Mg, Mn, Cu, Fe, and Co concentrations in petunia corollas from flowers at anthesis through senescence. Our results showed that all elements in our study were present in lower concentrations in corollas than mature leaves. Phosphorus concentration decreased from ≈2000 mg·kg-1 in presenescent corollas to 1500 mg·kg-1 in senescing tissue, a change correlated to increases in ethylene production by the corollas. Increases in Ca, Mg, and Mn concentrations were noted during development of corollas from anthesis to senescence. However, no clear correlation exists between these changes and the ethylene climacteric since increases were gradual and continuous from anthesis to senescence. Calcium concentrations increased 3- to 4-fold from anthesis to senescence. Changes in Mg and Mn concentrations were less pronounced and were limited to 2- to 3-fold increases for Mn and a 2-fold increase for Mg. Concentrations of Cu, Fe, and Co fluctuated throughout development and ranged from 2 to 14, 88 to 544, and 0 to 4 mg·kg-1, respectively.
Postharvest Development of Leaf Yellowing in Cut Asiatic and Oriental Lilies
Authors: Han Susan S.
Published: February 2019

The development of postharvest leaf yellowing affects the quality of cut Oriental and Asiatic lilies. Without cold storage, lower leaves began to turn yellow ≈1 week after placing them in an interior environment. The development of leaf yellowing continued to progress upward until the vase life was over with >25% of the leaves chlorotic. Cold storage of cut lilies worsened this leaf disorder. The longer the duration of cold storage, the sooner the development of leaf yellowing and the higher the percentage of leaves that were chlorotic. Spraying leaves with a solution containing 25 mg·L-1 each of BA and GA4+7 significantly reduced cold-stored induced leaf yellowing in both Oriental and Asiatic lily. While the growth regulator treatment completely prevented leaf yellowing of cold-stored Asiatic lilies, its effectiveness in Oriental lilies diminished with the duration of cold storage. Timing of the growth regulator application was not critical, as there were no differences in leaf yellowing when the growth regulator solution was sprayed before or after the cold storage. The concentration of the growth regulators was inversely related to the development of leaf yellowing and concentrations <5 mg·L-1 each of BA and GA4+7 were not effective. Alternative means of applying the growth regulators were evaluated, including the addition of the growth regulators to the preservative solution or as a pulsed treatment. Both methods completely prevented leaf yellowing but also induced bud abortion. For practical application, spraying the growth regulator solution on the leaves prior to or after cold storage would significantly improve postharvest quality of the cut lilies.
Optimum Height at Which to Kill Barley Used as a Living Mulch in Onions
Authors: Greenland Richard G
Published: February 2019

Planting barley (Hordeum vulgare L.) as a living mulch with onions (Allium cepa L.) reduces soil erosion and protects the onions from wind damage. It can also reduce yield and size of onion bulbs if not managed correctly. In a 4-year study at the Oakes Irrigation Research Site in North Dakota, barley was planted in the spring at the same time that onions were direct-seeded. Barley rows were planted either parallel with or perpendicular to the onion rows. Barley was killed with fluazifop-P herbicide when ≈13, 18, 23, or 30 cm tall. Onion size and yields were reduced when barley was allowed to grow taller than 18 cm before killing it. Total onion yield was usually greater when barley was planted parallel with, rather than perpendicular to, onion rows. Chemical name used: (R)-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy]phenoxy]propanoic acid (fluazifop-P).
Performance of Satsuma Mandarin Protected from Freezing Temperatures by Microsprinkler Irrigation
Authors: Nesbitt Monte L. , McDaniel N.R. , Ebel Robert C. , Dozier W.A. , Himelrick David G.
Published: February 2019

Several microsprinkler treatments were tested on 5-year-old satsuma mandarin orange (Citrus unshiu Marc.) trees to compare survivability of trunks and scaffold limbs in severe freezes. Three damaging freeze events occurred during winter, with two in 1995–96 and one in 1996–97. Air temperature dropped to –9.4, –5.6, and –6.7 °C, respectively. Almost 90% of the foliage was dead on the control plants after the first freezing event and 98% after the second. A single microsprinkler 1.6 m high in the canopy delivering 90.8 L·h–1 reduced injury; only 54% of the canopy was dead after the first freeze and 71% after the second. There was slightly more shoot-tip dieback on the plants in the microsprinkler treatments than on the control plants after the first two freezes. The amount of limb breakage by ice was minor. The third freeze killed 34% of the canopy in the control plants, but only 26% in the plants in the microsprinkler treatments. Use of microsprinklers increased yield in 1996, but yield for all treatments was very low. Yield for all treatments fully recovered in 1997, averaging 153 kg/tree. Although no death of scaffold limbs or trunks occurred, these results demonstrate that microsprinkler irrigation reduces damage to foliage and increases yield somewhat in severe freezes.
CPPU and BA, with and without Pollination, Affect Set, Growth, and Quality of Muskmelon Fruit
Authors: Hayata Y. , Niimi Y. , Inoue K. , Kondo S.
Published: February 2019

Solutions of CPPU and BA were applied to ovaries of melon (Cucumis melo) flowers with or without pollination, and the effects on fruit set, growth, and sugar content were investigated. Treatment with CPPU increased fruit set in both seeded and seedless melons. Even at low concentrations, CPPU had a strong effect on fruit set in the seeded melons. In seedless melons, CPPU induced 100% parthenocarpic fruit set when applied with 10 mg·L–1; lower concentrations were much less effective. Treatment with BA increased fruit set in seeded melons, but was not particularly effective in the absence of pollination. During the first 10 days after anthesis, CPPU promoted fruit growth, but between 8 and 13 days after anthesis, the growth rate was lower than in the controls. Treatment with CPPU had little effect upon soluble solids (SS) levels in seeded fruit. SS content was significantly lower in seedless than in seeded fruit; this difference was larger in the placenta than in the mesocarp. Sucrose levels of both seeded and seedless fruits were consistently higher than glucose and fructose levels. High concentrations of CPPU reduced sucrose levels in the placenta of seedless fruit. These results indicate that seeds play an important role in sugar accumulation and melon fruit growth during later stages of development. Chemical names used: [1-(2-chloro-4-pyridyl)-3-phenylurea] (CPPU); 6-benzylaminopurine (BA).
Management of Diamondback Moth (Lepidoptera: Plutellidae) in Cabbage Using Collard as a Trap Crop
Authors: Mitchell E.R. , Hu Guangye , Johanowicz Denise
Published: February 2019

Collard greens (Brassica oleracea var. acephala L.) were planted in the peripheries of cabbage (Brassica oleracea var. capitata L.) fields in the spring growing seasons of 1997 and 1998 to evaluate their effectiveness as a trap crop to manage the diamondback moth (DBM) [Plutella xylostella (L.)]. The numbers of DBM never exceeded the action threshold for application of insecticides in any of the fields that were completely surrounded by collards, but did exceed the action threshold in three of the fields without collards on four sampling dates in 1998. In both years, the numbers of DBM larvae in the collards exceeded the action threshold of 0.3 total larvae/plant in eight of nine fields. Larval counts in cabbage surrounded with collards were not significantly higher than in the conventionally planted cabbage, even though the number of pesticide applications was reduced in the former. The few pesticide applications in fields surrounded by collards probably targeted the cabbage looper [Trichoplusia ni (Hübner)], which was not impeded by the collards from infesting the interior cabbage. There was no significant reduction in marketability, and damage to cabbage was similar to that in fields where collards were planted and in fields where only conventional pesticides were used. The reduced number of pesticide sprays, as well as the high concentration of host larvae in the collards, may help maintain populations of natural enemies of DBM in the agroecosystem. Planting collards in field peripheries is a potentially effective tactic to manage DBM in cabbage.
Inheritance of Resistance to Passionfruit Woodiness Virus in Common Bean (Phaseolus vulgaris L.)
Authors: Provvidenti R.
Published: February 2019

Passionfruit woodiness virus (PWV) can infect bean (Phaseolus vulgaris L.), causing a light and dark green foliar mosaic, veinbanding, downward curling, and plant stunting. The intensity of these symptoms can vary with the strain of the virus and cultivar, but they resemble those caused by bean common mosaic virus. In genetic populations derived from crosses and backcrosses involving cultivars that are resistant (`Black Turtle 1', `Clipper', and `RedKote') or susceptible (`Black Turtle 2', `California Light Red Kidney', and `Pioneer'), a single dominant gene conferred resistance to an Australian strain PWV-K. To this gene, the symbol Pwv (Passionfruit woodiness virus) is tentatively assigned. In plants derived from rooted cuttings of backcross populations, the same factor also conditioned resistance to three other Australian strains, PWV-Mild, PWV-51, and PWV-Tip Blight.
Vacuum Cooling and Storage Temperature Influence the Quality of Stored Mung Bean Sprouts
Authors: DeEll Jennifer R. , Vigneault Clément , Favre Frédérique , Rennie Timothy J. , Khanizadeh Shahrokh
Published: February 2019

The objective of this research was to evaluate the effects of vacuum cooling and temperature on the quality and storage life of mung bean sprouts (Vigna radiata L. Wilczek). Sprouts in micro-perforated bags were either not precooled or vacuum cooled to 9, 6, or 3 °C, and stored for 7 days at 1, 3, or 6 °C. Vacuum-cooled bean sprouts lost more weight than sprouts not precooled, and the weight loss was greater when the sprouts were cooled to lower temperatures. However, the total loss never exceeded 5% and no apparent signs of shrivel were observed. Vacuum cooling resulted in greater product freshness after 4 days of storage, but the effect was nonsignificant after 7 days. Storage temperature had greater influence on bean sprout quality than did cooling temperature, with greater freshness and whiter hypocotyls at the lower temperatures. However, blackening of cotyledons increased as the storage temperature decreased.
The Use of Vinegar Vapor to Reduce Postharvest Decay of Harvested Fruit
Authors: Sholberg Peter , Haag Paula , Hocking Rod , Bedford Karen
Published: February 2019

Vapors of several common vinegars containing 4.2% to 6.0% (= 2.5 to 3.6 mol·L-1) acetic acid effectively prevented conidia of brown rot [Monilinia fructicola (G. Wint.) Honey], gray mold (Botrytis cinerea Pers.:Fr.), and blue mold (Penicillium expansum Link) from germinating and causing decay of stone fruit (Prunus sp.), strawberries (Fragaria ×ananassa Duchesne), and apples (Malus ×domestica Borkh.), respectively. Fruit were fumigated in 12.7-L sealed containers in which vinegar was dripped on to filter paper wicks or vaporized by heating from an aluminum receptacle. Vapor from 1.0 mL of red wine vinegar (6.0% acetic acid) reduced decay by M. fructicola on `Sundrop' apricots (Prunus armeniaca L.) from 100% to 0%. Similarly, vapor from 1.0 mL of white vinegar (5.0% acetic acid) reduced decay in strawberries by B. cinerea from 50% to 1.4%. Eight different vinegars, ranging from 4.2% to 6.0% acetic acid, of which 0.5 mL of each vinegar was heat-vaporized, reduced decay by P. expansum to 1% or less in `Jonagold' apples. The volume of heat-vaporized white vinegar (5.0% acetic acid) necessary to reduce decay by P. expansum on `Jonagold' apples to zero was 36.6 μL·L-1 of air. Increasing the number of conidia on the apple surface reduced the effectiveness of vinegar vapor. The number of lesions caused by P. expansum on `McIntosh' apple decreased exponentially with increasing time of fumigation, approaching zero after about 6 hours. These results suggest that vinegar vapor could be an effective alternative to liquid biocides such as sodium hypochlorite for sterilization of surfaces contaminated by conidia of fungal pathogens.
Cultivar and Developmental Differences in S-protein Concentration and Self-incompatibility in the Japanese Pear
Authors: Zhang Shao-Ling , Hiratsuka Shin
Published: February 2019

Cultivars of the Japanese pear [Pyrus pyrifolia (Burm.) Nakai] have variable degrees of self-incompatibility (SI) and can be classified into at least three groups: strong, intermediate, or weak SI; as shown by the extent of self-pollen tube growth in the style, and the percentage of fruit set following self-pollination. Following self-pollination, the elongation of pollen tubes in the detached styles of `Kosui' and `Kikusui' became increasingly suppressed from 4 days before anthesis (–4 DAA) to 2 days after anthesis (2 DAA). Tube growth of `Kosui' was more suppressed than that of `Kikusui' during this period. In `Osa-Nijisseiki', however, the rate of tube growth did not vary with stage of stylar development, from –8 to 2 DAA. Pollen tubes elongated much better after cross-pollination than after self-pollination at all stages tested, and the extent of the elongation increased as the styles matured. The concentration of total S-protein (sum of two S-proteins per buffer-soluble protein) increased with stylar development, but the rate of increase varied with the cultivar. The rate was significantly greater in the strongly self-incompatible `Kosui' than in the moderately self-incompatible `Kikusui', and was slowest in the weakly self-incompatible `Osa-Nijisseiki' at all developmental stages. During stylar maturation, the concentration of S4-protein, which is common in all cultivars, was highest in `Kosui', followed by `Kikusui' and `Osa-Nijisseiki'. Thus, the cultivar differences in SI expression in the Japanese pear are determined about –4 DAA and appear to be regulated, in part, by the concentration of S-proteins produced in the style.
Alternate Bearing Intensity of Pecan Cultivars
Authors: Conner Patrick J. , Worley Ray E.
Published: February 2019

The Coastal Plain Experiment Station has been evaluating pecan [Carya illinoinensis (Wangenh.) K. Koch] cultivars for over 75 years. Using annual yield data from this program, the alternate bearing intensities (I) of 66 pecan cultivars and numbered U.S. Dept. of Agriculture (USDA) selections were determined. Values ranged from 0.19 to 0.93 in young trees, and from 0.27 to 0.91 in mature trees under high-input production practices. The adoption of fungicides, insecticides, and irrigation during the last 30 years has reduced the average I value from 0.70 to 0.55. I was negatively correlated with both nut yield and nut weight. All but one cultivar recommended for commercial production in Georgia have I values lower than the average of 0.57 for all cultivars in this test. Values calculated early in a tree's productive life cycle were highly correlated with those of mature trees.
Weed Control in Carrots: The Efficacy and Economic Value of Linuron
Authors: Bell Carl E. , Boutwell Brent E. , Ogbuchiekwe Edmund J. , McGiffen Milton E.
Published: February 2019

Application of linuron was compared with hand-weeding and a nontreated control (= control) for weed control in carrots. Linuron, applied pre- or postemergent, was slightly less effective than the 100% weed control obtained by hand-weeding. Carrot yields were similar for all treatments, and were at least six times as great as in the control. In 1996, linuron treatments returned net profits ranging from $980 to $1887 per ha, compared to $740 for hand-weeding and -$2975 for the control. In 1997, return on linuron treatments was greater, ranging from $5326 to $6426, compared with $2852 for hand-weeding. Marginal rates of return ranged from 21% to 86% in 1996. In 1997, rates of return for every dollar invested in linuron were over 59%. Chemical name used: N′-(3,4-dichlorophenyl)-N-methoxy-N-methylurea (linuron).
A Toothpick Inoculation Method for Evaluating Carrot Cultivars for Resistance to Alternaria radicina
Authors: Pryor B.M. , Davis R.M. , Gilbertson R.L.
Published: February 2019

The susceptibility of 46 carrot cultivars to infection by Alternaria radicina Meier, Drechsler, and Eddy, causal agent of black rot disease, was evaluated in field trials with a toothpick inoculation method. Toothpicks infested with A. radicina were inserted into the shoulders of 10- to 12-week-old carrots (Daucus carota L.) and lesion areas were measured 9 to 10 weeks later. There were significant differences in lesion size among cultivars. Relatively resistant cultivars included `Panther' and `Caro-pak', and susceptible cultivars included `Royal Chantenay' and `Nogales'. Nine of the cultivars were inoculated with A. radicina-infested toothpicks and maintained in cold-storage for 10 weeks. Lesion development was greater in cold-storage than in the field, but the relative ranking of cultivars in terms of resistance to A. radicina was similar.
Ultrastructural Characterization of Yellow Shoulder Disorder in a Uniform Ripening Tomato Genotype
Authors: Francis David M. , Barringer Sheryl A. , Whitmoyer Robert E.
Published: February 2019

Yellow shoulder disorder (YSD) is characterized by sectors of yellow or green tissue under the peel of uniform ripening tomato (Lycopersicon esculentum Mill.) fruit. Tissues excised from sectors of fruit expressing YSD, from adjacent red sectors, and from mature green fruit were used to compare the ultrastructural alterations in cells and tissue affected by YSD and to determine whether the disorder is caused by delayed fruit maturation or by aberrant development. Cells from YSD sectors were smaller than those from both adjacent red-ripe tissue and mature green fruit. The smaller cells from the YSD sectors were at a different developmental stage than cells of the adjacent red-ripe tissue. Chromoplasts in red-ripe tissue were more advanced in development than those in YSD sectors or mature green fruit. Using the transition from chloroplast to chromoplast and the degradation of the middle lamella between adjacent cells as developmental markers, the maturity of tissue from YSD sectors appeared to be equal or greater than that of tissue from mature green fruit. However, cell enlargement, which takes place early in fruit development, was retarded in YSD sectors. Therefore, the ultrastructural features of YSD are not compatible with a delayed ripening model for this blotchy ripening disorder. These observations provide a basis for comparing YSD in uniformly ripening tomatoes with other blotchy ripening disorders.
In Vitro Rooting and Subsequent Survival of Two Clones of a Cold-tolerant Eucalyptus grandis × E. nitens Hybrid
Authors: Mokotedi M.E. Oscar , Watt M. Paula , Pammenter Norman W. , Blakeway Felicity C.
Published: February 2019

Multiple shoots of two Eucalyptus grandis Hill ex Maid. × E. nitens (Deane & Maid.) Maid. clones (GN121 and GN107) generated from axillary buds were used for in vitro rooting studies. The highest rooting rates in clones GN121 (75%) and GN107 (65%) were achieved on modified 1/4-strength Murashige and Skoog (MS) (1962) medium (Ca2+ and Mg2+ levels as for 3/4-strength MS), 0.5 μm IBA, 0.4 μm biotin, 0.2 μm calcium pantothenate, 0.04 m sucrose and 0.4% (w/v) Gelrite®. The optimal culture conditions were an initial 72-h dark incubation period followed by a 16-hour photoperiod at a photosynthetic photon flux density (PPFD) of 37 μmol·m-2·s-1 and 23 °C day/21 °C night for 7 days, after which the PPFD and temperature were increased to 66 μmol·m-2·s-1 and 27 °C day/21 °C night for 18 days. Plantlets were acclimatized with survival rates of 78% for GN121 and 58% for GN107 after 28 days. Chemical name used: indole-3-butyric acid (IBA).
Double-cropping Muskmelons with Nematode-resistant Tomatoes Increases Yield, but Mulch Color Has No Effect
Authors: Hanna H.Y.
Published: February 2019

A study was conducted in Summer 1996 and 1997 to determine the residual effects of planting nematode-resistant vs. susceptible tomato (Lycopersicon esculentum Mill.) cultivars and use of white vs. black polyethylene mulch on the growth and yield of a subsequent muskmelon (Cucumis melo L.) crop. Tomato cultivars were planted in early April and harvested in June and early July. Muskmelons were planted in late July on the same beds. Muskmelons, planted after the nematode-resistant tomato cultivar Celebrity, produced significantly greater marketable yield and more fruit per hectare in both years than did muskmelons planted after the nematode-susceptible tomato cultivar Heatwave. Plant dry weight of muskmelons was greater and the percentage of their galled roots was smaller when planted after nematode-resistant tomatoes than when planted after nematode-susceptible ones. Mulching tomatoes with black or white polyethylene had no significant effect on growth, yield, and root galling of subsequent muskmelon crops.