bluuebunny/crossref_metadata_2025 huggingface dataset:
Natural Landscapes in Urban Settings: A Regulatory Jungle
Authors: Balbach Harold E. , Balbach Margaret K.
Published: February 2019

Thousands of property owners annually attempt to develop a natural landscape on their property. Annually, thousands of people are cited for violation of “weed laws,” nuisance laws, subdivision covenants, and other local ordinances. Often, these regulations allow the city to mow the “weeds” first and follow up with fines, bills, and other legal actions. How reasonable are these requirements? What is the basis of the regulations? How do they vary by state and locality? Is every property required to have a smooth, unbroken bluegrass lawn? A variety of case studies across the midwest shows much local variation in both the wording of the ordinances and local tolerance for diversity of landscaping goals. The most successful responses require considerable planning and effort, and the least successful attempts are simplistic “no more mowing” declarations.
Development of a Simulation Model to Predict Growth and Yield of Pickling Cucumber
Authors: Shuman Joel L. , Wehner Todd C.
Published: February 2019

Production of pickling cucumber (Cucumis sativus L.) requires a significant expenditure of labor and money. Those resources could be better managed if both yield and harvest date could be predicted for a given planting date and production area. The objective of this experiment was to develop a model to simulate growth and yield of pickling cucumbers under field conditions in North Carolina. Detailed measurements of leaf area, branching habit, flowering, fruiting, and dry weight distribution were obtained for the cultigens `Calypso', M 21, `Wis. SMR 18', and WI 2757 for 10 planting dates. Light interception, air temperature, and rainfall were also recorded. There were differences among cultigens and planting dates for time needed to reach certain growth stages. Number of days to reach a given stage generally decreased with later planting dates. Addition of nodes over time to the main stem was linear and the interaction of planting date by cultigen was significant. Number of staminate and pistillate flowers was affected by both cultigen and planting date.
Wax Effects on Postharvest Storage of `Fallglo' Tangerines
Authors: Dou Huating , Petracek Peter D.
Published: February 2019

`Fallglo' is an early season variety of tangerine that has become known among citrus packers for its susceptibility to postharvest peel disorders. Among these disorders is postharvest pitting, a disorder characterized by the collapse of the peel during the storage of waxed fruit at room temperature. In this study, the effects of wax application on selected postharvest storage characteristics were evaluated.

Fruit were either not waxed or waxed with carnauba-, polyethylene-, or shellac-based waxes obtained from four suppliers of commercial citrus coatings and were stored at 21°C. In general, waxing reduced weight loss and improved shine. Waxing with shellac-based waxes significantly decreased internal O2 levels (5% vs. 19% for non-waxed fruit) and increased internal CO2 (6% vs. 2% for non-waxed fruit) and ethanol levels. Waxing with shellac-based waxes also significantly reduced post-packing degreening and stimulated pitting. Waxing with more gas-permeable coatings (carnaubaand polyethylene-based waxes) resulted in less internal gas modification than that of the shellac-based treatments, and low incidences of pitting. Controlled atmosphere studies showed that low (4%) O2, rather than high (8%) CO2, inhibited post-packing degreening and stimulated pitting.
Minimal Pruning during Orchard Development Improves Yield of Late-season `Fairtime' Peaches
Authors: Day Kevin R. , Johnson R. Scott
Published: February 2019

Minimal dormant pruning after the first and second growing seasons, followed by standard pruning thereafter, improved total tree yield in the 3rd, 4th, and 5th years after planting. Trees that were pruned in accordance with standard local practice had ≈50% yield compared to minimally pruned trees in years 3 through 5. Fruit from minimally pruned trees was sgnificantly smaller, but mathematical adjustment of crop load indicated that overall yield efficiency was improved in the 3rd and 4th years for trees receiving minimal pruning.
Advancing Fruit Ripening in Stone Fruit Species
Authors: Erez A. , Yablowitz Z. , Korcinski R.
Published: February 2019

Fresh fruits of stone fruit species are either lacking or in short supply in the months of March and April on the world market. This results from the absence of late-maturing cultivars in most of these species and from their poor storage capabilities. In March–April, supply from the Southern Hemisphere is dwindling or finished, while supply from the Northern Hemisphere has not started yet. A horticultural system was developed in Israel to get early fruit ripening of stonefruit species. The system developed is based on early completion of dormancy requirements followed by greenhouse tree growing. The system uses the following elements: 1) Improve chilling accumulation in winter by using evaporative cooling, to prevent chilling negation by high day temperatures. 2) Monitor salt accumulation level to prevent damage to branches and buds. 3) Monitor bud temperature and evaluate dormancy development according to the dynamic model. 4) Use dormancy breaking chemicals to compensate for part of the chilling not applied. 5) Cover of the trees with polyethylene having the appropriate characteristics of light filtering. 6) Keep the temperature in the greenhouse lower than the maximal temperature allowed, at every specific stage of development by ventilation. By using this system, fruit ripening was advanced by 4 to 6 weeks in peaches and nectarines (harvested from late March) and by 4 weeks in sweet cherries (harvested from April 11). Yields of 20 to 30 tons/ha were obtained in both species with high fruit quality.
Avoiding Internal Breakdown of Stone Fruit by an “Off” the Tree Pre-ripening Treatment
Authors: Crisosto Carlos H. , Johnson R. Scott , Crisosto Gayle M. , Labavich John , Garner David
Published: February 2019

During the past two seasons, the relationship between fruit ripening “ON” or “OFF” the tree and internal breakdown incidence was studied with `Elegant Lady' and `O'Henry' peach cultivars. Internal breakdown (IB) visual symptom development was delayed in fruit harvested at different physiological maturities and exposed to different “OFF” the tree pre-ripening treatments. As a follow up, different pre-ripening treatments (controlled delayed cooling) were tested for several peach, nectarine, and plum cultivars susceptible to IB. This pre-ripening treatment delayed flesh browning, mealiness, and off-fl avor development after a simulated shipment and retailer handling period for `Flavorcrest', `Elegant Lady', `O'Henry', `Parade', `Fairtime', `Carnival', `Prima Gattie', `Last Chance', `Autumn Gem', `Autumn Lady', and `Autumn Rose' peaches; `Summer Grand' and `September Red' nectarines; and `Fortune' plum. However, decay development may be a problem. Delayed cooling at 20°C must be carried out with fruit protected with fungicide and wax for the shortest possible, but still effective, length of time to limit IB. The temperature and the length of this pre-ripening treatment, and the presence or absence of ethylene during the delayed cooling is cultivar dependent. Thus, specific pre-ripening conditions must be developed for each cultivar.
Sweetpotato Weevil Resistance to Stem and Root Injury Sweetpotato Plant Introductions
Authors: Thompson Paul G. , Graves Boyett , Schneider John C.
Published: February 2019

The sweetpotato weevil is the most-destructive worldwide pest of sweetpotato and only low to moderate levels of resistance to the insect are available in acceptable cultivars. No sources of high resistance levels have been identified; consequently, there is a need to identify additional sources of resistance genes to develop high resistance levels. To begin a search for sources of resistance, plant introductions were evaluated for injury levels. In 1993, 100 plant introductions were evaluated for sweetpotato weevil injury and 62 of the least injured were tested again in 1994. In 1995, 36 of the least injured in 1993 and 1994, plus 24 additional PIs were evaluated. Control cultivars included `Regal', moderately resistant; `Jewel', intermediate; and `Beauregard' and `Centennial', susceptible. Measurements of injury were percentage of roots injured, and, stem and root injury scores based on a 0–5 scale, with 0 being no injury. First year results indicated that a low level of resistance to stem injury is available in the PIs tested. Stem injury was more severe in the following year and no differences were found. Lower weevil populations will be required to screen for low levels of stem injury resistance. Percentage injured roots and root injury scores were lower over the 3 years for five PIs than for `Regal'.
Effect of Stock Plant Photoperiod and Temperature on Cutting Production and Rooting of Herbaceous Perennials
Authors: Koreman Paul , Cameron Art , Heins Royal , Carlson William
Published: February 2019

Previous research has shown that the photoperiod under which stock plants are grown has a significant effect on cutting production and rooting of several species of herbaceous perennials. Long-day (LD) treatment of stock plants promoted cutting production of certain LD perennials but reduced rooting. Cuttings from plants grown under short days rooted readily but few were produced. Stock plants were exposed to alternating photoperiods to determine if this treatment would yield many cuttings with high rooting potential. Coreopsis verticillata `Moonbeam' and Phlox paniculata `Eva Cullum' stock plants were given 4 weeks of 4-h night interruption (NI), while Sedum `Autumn Joy' stock plants were grown under 14-h days. After 4 weeks plants were given 0, 2, or 4 weeks of 10-h days. Cuttings were harvested and propagated under mist and three different photoperiods (10-h, 14-h, NI) for 4 weeks, after which rooting percentage and the number and length of roots produced by each cutting were measured. The results will be presented.
Photoperiodic Responses of Garden Chrysanthemum
Authors: Will Elizabeth , Starman Terri W. , Faust James E. , Abbitt Shane
Published: February 2019

The objective was to study the flowering response of garden cultivars of Dendranthemum × grandiflorum (Ramat.) Kitamura to temperature and photoperiod. Fifteen garden mum cultivars were grown in ten temperature (18 and 24°C constant day and night greenhouse temperatures) and photoperiod (8, 10, 12, 14, and 16 h) combinations. Rooted cuttings were pinched above the fifth node and placed in the temperature/photoperiod treatments. When axillary shoots developed, all but one shoot was removed to produce a single stemmed plant. Photoperiods were provided by delivering 8 h sunlight, then pulling black cloth and providing daylength extension with incandescent bulbs. Days to visible bud, days to first bud color, days to flower, node number, and stem length were measured. By 11 weeks after the start of photoperiod treatments, no difference was measured in days to flower in the 8-, 10-, and 12-h photoperiods at 18°C. Days to flower increased as photoperiod increased from 12 to 14 h. At 18°C, five cultivars flowered in the 16-h photoperiod, while 10 cultivars developed crown buds, i.e., flower buds that initiated but had not developed. At 24°C, there was no difference in days to flower in the 8and 10-h photoperiod, while days to flower increased as photoperiod increased from 10to 12-h treatment. Cultivars formed crown buds but had not reached flowering in the 14and 16-h photoperiods at 24°C. Regardless of temperature, stem length increased as photoperiod increased above 10 h.
Red/Far Red Light and PAR Leaf Absorption Varies among Hanging Basket Crop Species
Authors: Cutlan A. , Nordwig G. , Warner R. , Erwin J.E.
Published: February 2019

Variation in red/far red leaf and photosynthetically active radiation (PAR) absorption by an individual leaf of various ornamental hanging basket species was measured. Red/far red ratios varied from 0.30 to 0.83 for Syngonium podophyllum Schott. and Chlorophytum comosum Thunb. `vittatum', respectively. Reduction in PAR varied from 86% to 61% for those same species, respectively. Estimated state of phytochrome photoequilibria for understory crops when grown under each species was calculated. Cucumis sativus L. seedling hypocotyl elongation was measured under different species to validate hypothesized differences in stem elongation associated with differences in red/far red filtering through individual leaves. Implications with respect to light quality effects on stem elongation and dry weight accumulation of plants grown under different species are discussed.
Effect of School Gardens on Environmental Attitudes of Children
Authors: Waliczek Tina M. , Zajicek J.M.
Published: February 2019

Children develop their personalities and attitudes at an early age. With children spending a large portion of their waking hours in the classroom, schools are a major influence on many factors including environmental attitudes. Studies in human issues in horticulture have focused on how gardens and nature affect other variables in children, but few have focused on environmental attitudes of children in mainstream school districts. The main goal of this study was to initiate and integrate an environmental education garden program into the curriculum of several schools in the midwest and Texas. One objective of the research project included evaluating whether the students participating in the garden program developed positive environmental attitudes as a result of participation in the garden program. The garden program, Project Green, was designed to provide thirdthrough eighth-grade teachers some basic garden activities that could be infused into their classroom lessons and would serve to reinforce curriculum in various disciplines with hands-on activities. Eight schools, ≈1000 students, took part in the study. Students participating in the study were administered a pre-test prior to participation in the garden program and an identical post-test after its completion. Comparisons were made between children based on age, ethnic background, gender, and length of garden season. Results examine the relationship between the garden program, environmental attitudes of children and demographic variables.
Project GREEN: The Effect of Gardening on Environmental Attitudes of Elementary School Students
Authors: Skelly Sonja M. , Zajicek J.M.
Published: February 2019

Project GREEN (Garden Resources for Environmental Education Now!) is an educational tool to assist in the teaching of environmental education at the elementary school level. Project GREEN is different from many current educational practices because its major goal is to provide an interdisciplinary approach to environmental education by infusing activities centered around a hands-on tool, “the garden.” The main goal of this project included evaluating whether students participating in Project GREEN were developing positive environmental attitudes. Three schools throughout Texas participated in the study. Approximately 200 students were evaluated; 100 participants served as the experimental group and 100 non-participants served as the control group. Students were evaluated using the Children's Environmental Response Inventory (CERI), which measures students' attitudes about nature and human dominance over nature. This questionnaire also contained a section for biographical information. Comparisons were made between the experimental and control groups, as well as between gender, age, ethnicity, and time in the garden. Results examine the relationship between the garden program and environmental attitudes for both control and experimental groups.
Plant Growth Regulators (GA3 and CCC) and Silverleaf Whitefly Effects on the Induction of Tomato Irregular Ripening in Dwarf Cherry Tomato
Authors: Hanif-Khan S. , Stoffella P.J. , Brecht J.K. , McAuslane H.J. , Bullock R.C. , Powell C.A. , Yokomi R.
Published: February 2019

External and internal tomato irregular ripening (TIR) symptoms have been associated with the feeding of silverleaf whitefly (SLW), Bemisia argentifolii Bellows and Perring. Soil drench application of gibberellic acid (GA3) (100 ppm, Trial 1 and 2) and cycocel (CCC) (2000 ppm, Trial 1; 1000 ppm, Trial 2) were applied to dwarf cherry tomato (Lycopersicon esculentum) in the presence and absence of SLW to mimic the TIR disorder induced by the SLW. Application of GA3 induced external and internal TIR symptoms similar to the SLW-induced disorder in `Florida Petite'. There were essentially no TIR symptoms in fruit treated with CCC, an inhibitor of GA biosynthesis. In Trial 1, internal white tissue in GA3, SLW, and CCC treatments was expressed in 97%, 95%, and 4% of the total fruit, respectively. Incidence of external TIR symptom was highest (56%) in the GA3 plus SLW treatment. In Trial 2, GA3 application in the presence (83%) or absence (85%) of SLW resulted in the highest incidence of fruit with internal white tissue. External TIR symptoms induced by GA3 in the presence and absence of SLW were reduced with CCC application. These results suggest that the TIR disorder in tomato is induced by the SLW may be a GA3-regulated disorder.
Effect of Chitosan on Tissue Maceration and Enzyme Production by Erwinia carotovora in Potato
Authors: Reddy M.V. Bhaskara , Asselin Alain , Arul Joseph
Published: February 2019

We have investigated the relationship between chitosan treatments and maceration of potato tissue by macerating enzymes secreted by Erwinia carotovora causal agent of soft rot of potato. Erwinia isolated from potato showing soft rot symptoms was used for inoculation. The bacteria secreted a wide spectrum of enzymes that degraded potato cell walls. Polygalacturonase (PG), pectate lyase (PL), pectinmethylesterase (PME), cellulase, xylanase, and protease showed the highest activity in potato tissue inoculated with the pathogen. Accordingly increased maceration and cell death were observed. On the other hand, in chitosan-treated tissue and challenged with the pathogen, significant decrease in enzymatic activity and tissue maceration were observed, more so with increasing chitosan concentration. This observation confirmed that chitosan interfered with multiplication and pathogenic powers of the bacteria, thereby improving cell texture and viability. Crude extracts obtained from treatments were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to assess pectinase activity. The electophoretic profiles showed significant lytic zone of pectin degradation in the control, which decreased with increase in chitosan concentrations. No lytic zone was observed at 8 mg·ml–1 chitosan concentration and was comparable to intact activity in untreated potato tissue. Pectic enzyme reaction products were analyzed to see the action pattern of pectinases in the crude extracts. Cellulose choromatographic profiles revealed monomers and dimers of polygalacturonic acid up to 6 mg·ml–1 chitosan concentrations. The results suggest that chitosan significantly inhibits bacterial growth and the production of macerating enzymes by the pathogen and thus chitosan can be a potential anti-bacterial agent.
Simulation of the Time Courses of CO2 Concentration in the Culture Vessel and Net Photosynthetic Rates of Potato Plantlets Cultured Photoautotrophically and Photomixotrophically in Vitro under Different Lighting Cycles
Authors: Niu Genhua , Hayashi Makio , Kozai Toyoki
Published: February 2019

Potato (Solanum tuberosum L. cv. Benimaru) plantlets were cultured under four lighting cycles (photoperiod/dark period: 16 h/8 h, 4 h/2 h, 1 h/0.5 h, and 0.25 h/0.125 h) photoautotrophically (without sugar in the medium), and photomixotrophically (with sugar in the medium) in vitro for 28 days. Simulations of time courses of CO2 concentration in the vessel (Ci) and dry weight accumulation of the plantlets cultured photoautotrophically were conducted using a previously developed model (Niu and Kozai, 1997). While underestimation and overestimation of time courses of Ci in some treatments were observed, the simulated results of Ci and dry weight accumulation of the plantlets generally agreed with the measured ones. The difference of net photosynthetic rate response to Ci throughout the culture period was examined between the plantlets cultured photoautotrophically and photomixotrophically. Quantitative relationship between daily net photosynthetic rate (daily net production) and vessel ventilation rate per plantlet was simulated under various CO2 levels outside the vessel for given sizes of potato plantlets cultured photoautotrophically in vitro to aid appropriate CO2 enrichment and vessel design in commercial micropropagation.
Effects of Nitrogen and Sucrose Level on the Regeneration of Cichorium intybus L. var. sativus
Authors: Lim Hak Tae , Park E.J.
Published: February 2019

The regeneration medium supplemented with 2.0 mg/L BAP and 0.1 mg/L IAA allowed high efficient shoot regeneration from leaf discs and petioles of Cichorium intybus L. var. sativus. Multiple shoots ranged from 10 to 14 per explant were observed only 10 to 15 days after the initial culture. Reduced nitrogen and sucrose levels influenced on shoot regeneration frequency and growth rates. Especially, in C. Intybus L. var. sativus cv. Cesare explants cultured in the medium containing 50 mg/L MS macroelement and 1.5% sucrose displayed high regeneration frequency of 100%.
Yield and Quality of `Banaty' Grapes in Response to Spraying Iron and Zinc
Authors: Ahmed Faissal F. , Akl Ahmed M. , El-Morsy Farag M.
Published: February 2019

During 1995 and 1996, yield and quality of `Banaty' grapes in response to spraying chelated iron and zinc singly or in combination each at 0.025%, 0.05%, 0.1%, 0.2%, or 0.3% was investigated. Each concentration was applied once, twice, three, four, or five times. Results showed that there was a gradual increase in berry set, cluster number, yield, cluster weight, berry weight, total soluble solid sugars, and total anthocyanins with rising concentrations and number of sprays of each fertilizer. Total acidity tended to reduce with such treatment. Combined spray of both fertilizers, particularly at 0.1% four times, gave satisfactory improvement in both quantity and quality of grapes. Spraying at concentrations higher than 0.1% or spraying more than four times failed to show any measurable effect on all of the studied traits. The best results with regard to yield and quality of `Banaty' grapes were obtained on vines that received four sprays of iron and zinc each at 0.1% in chelated form.
Behavior of `Red Roomy' Grapevines to Application of Urea, Urea-formaldehyde, Sulfur, and Some Iron Compounds
Authors: Akl A.M. , Ahmed Faissal F. , El-Morsy Farag M. , Ragab Mohamed A.
Published: February 2019

The effect of single or combined application of urea-formaldehyde at 80 g N/vine, sulfur at 0.4%, and three compounds of iron (chelated, sequestered, and sulfate forms as 0.1%) on productivity of `Red Roomy' grapevines was studied during 1995 and 1996. A substantial increase in berry set, number of clusters, yield weight of clusters and berries, total soluble solid sugars, and anthocyanins was observed because of the application of these fertilizers singly or in combination. Total acidity in the juice was reduced because of application of these fertilizers. Combined application of urea-formaldehyde, sulfur, and chelated iron gave the best results with regard to yield and quality of berries. An economical yield was obtained on `Red Roomy' vines supplied with urea-formaldehyde at 80 g/vine, sulfur at 0.4%, and chelated iron at 0.1%.
The Phloem Mobility of Boron Alters Symptom Expression and Management of Boron in Plants
Authors: Brown P.H. , Hu H.
Published: February 2019

We have demonstrated that boron (B) is freely phloem mobile in a number of crop species and we predict that B will be mobile in all species that transport polyols (mannitol, sorbitol, dulcitol). This finding directly contradicts accepted dogma and profoundly influences the diagnosis and management of B in almond, apple, apricot, cherry, pear, peach, plum, prune, celery, and other species. In the majority plants, B moves in the xylem with the transpiration stream. Once B enters the leaf, it remains there with little or no redistribution. As a result, there is always a decreasing concentration gradient of B from old to young leaves and B toxicity symptoms always occurs in the old leaves first, typically exhibiting tip and margin burn. In species in which B is mobile, these symptoms do not occur. When almond, peach, and plum were exposed to high B in the growth medium, the predominant site of B accumulation was fruit, young stems and apical meristems. As a consequence, the earliest symptoms of B toxicity in species in which B is phloem mobile are observed in the young shoot meristems and fruits. Foliar application of 10B isotope demonstrates that B is readily transported to neighboring fruits and buds of almond, apple, and nectarine. In apple seedlings, plant B requirements can be fully satisfied solely by foliar application to a few mature leaves. This strongly suggest that foliar B applications can be used as an efficient means for B fertilization in Malus, Prunus, and Pyrus species. Details of the studies and their implications for B management will be discussed.
Effects of Root Zone Temperature on the Kinetics of Nitrogen Uptake of Non-bearing Apple Trees
Authors: Toselli Moreno , Flore James A. , Marangoni Bruno
Published: February 2019

Low root-zone temperature is one of the potential causes of low rate of plant nutrient uptake in spring. In this period, fruit trees are frequently supplied with nitrogen and a delay in root absorption could lead to an increase of nitrate leaching. In this study we assessed the effect of low root temperature on kinetic of nitrogen absorption of apple trees. One-year-old rooted cuttings of `Mark' apple rootstocks were subjected to two root temperature: 8 ± 1°C (LT) and 23 ± 1°C (HT). Four days after treatment imposition, the potted plants were supplied with 20 mg of N as NH4N03, enriched with 10 atom% of 15N. One, 2, 4, and 8 days after fertilization, tree root system was inserted into a Sholander bomb where a 0.325-Mpa pressure was applied to collect the xylem sap from the stem cross section. The sap exudation rate was always depressed by low root temperature. Nitrogen flow through the xylem vessel was highest in HT plants the day after fertilization (10-fold higher than LT), then decreased constantly. In LT plants, N flow was low the first and the second day after fertilization then reached the maximum 4 days after fertilization, when it was significantly higher than in HT plants. The amount of fertilizer-N found in leaves reflected the different movement rate of N observed in the two treatments. In HT trees fertilizer-N reached a plateau 2 days after fertilization, while in LT it linearly increased over time. This results suggest that root zone temperature of 8°C, although causes a delay (2–4 days) in nitrogen uptake, does not represent a serious limiting factor for N nutrition of tested apple trees.
Relationship Between Antiplatelet Activity and Sulfur Fertility in Hydroponic and Field-grown Onions (Allium cepa)
Authors: Orvis Kathryn S. , Goldman Irwin L.
Published: February 2019

Organosulfur compounds in onion extracts inhibit the aggregation of human blood platelets. Antiplatelet activity is important to human cardiovascular health. We hypothesized that modification of sulfur fertility may increase organosulfur compound concentration and thereby affect platelet inhibitory activity in onion. Four contrasting onion genotypes were grown at four sulfur levels in a hydroponic system in the greenhouse and in contrasting sulfur environments in seven field locations in Wisconsin, Oregon, and New York. The contrasting field sites were comprised of sandy soils with a mean sulfate level of 5.4 ppm and muck soils with a mean sulfate level of 20.3 ppm. Onions grown in field environments with increased soil sulfur concentrations had significantly higher antiplatelet activity (33% higher than sand-grown onions; P < 0.001). The greenhouse experiment was conducted in hydroponics with nutrient solutions containing four sulfur levels ranging from 0.8 mM to 15 mM sulfate. The 10-mM sulfur treatment resulted in onion bulbs with 10% higher antiplatelet activity over those grown in the 0.8-mM sulfur treatment (P < 0.06). These data suggest that sulfur concentration in nutrient solution and in soil may be directly responsible for the increased antiplatelet activity in onion extracts observed in this study.
Multi-site Thinning Comparisons with `Empire' and `McIntosh' Apples
Authors: Lakso Alan N. , Robinson Terence L. , Stover Eddie W. , Stiles Warren C. , Hoying Stephen , Iungerman Kevin , Telgheder Craig , Watkins Chris , Silsby Kenneth
Published: February 2019

Many chemical, environmental, and physiological factors have been reported to be important to apple chemical thinning, so we have been developing a multi-site and multi-year database of chemical thinning results and potentially important factors. For 3 years, we have conducted replicated thinning trials in `Empire' and `McIntosh' apple orchards at six or seven sites around New York state in different climatic regions. Different concentrations of NAA and Accel (primarily benzyladenine), NAA/carbaryl and Accel/carbaryl combinations and unthinned controls were tested with treatments applied at the 10-mm king fruit stage by airblast sprayers. Flower cluster counts, set counts, yields, fruit sizes, and other factors thought important to thinning response (orchard condition/history, weather, application conditions, etc.) were measured or estimated in each trial. Analysis of factor importance is continuing, but some general results have come from the thinning trials so far. Thinning effectiveness varied among years from poor to adequate. There have not been consistent thinner concentration responses. Commercial NAA and Accel concentrations have not thinned adequately. NAA/carbaryl and Accel/carbaryl have thinned the most. For the same crop load, trees thinned with Accel or the carbaryl combination have had better fruit size than when thinned with NAA.
Blossom Thinning Effects of Pelargonic Acid, Endothalic Acid, and Hydrogen Cyanamide in Apple and Peach
Authors: Fallahi Esmaeil
Published: February 2019

Effects of various concentrations of Dormex (hydrogen cyanamide, a.i. = 49%), pelargonic acid and endothalic acid, applied at 60% and full-bloom, on fruit set and yield of `Early Spur Rome' apple and `Redhaven' peach were studied over 2 years. A full-bloom application of Dormex at 0.25% and 0.31% (% formulation) alone or 0.125% endothal followed by a post-bloom thinner reduced fruit set and increased fruit size in apple. A double application of endothal at a rate of 0.125%, once at 70% bloom and again at full-bloom, also was effective in thinning and increased fruit size in apple. Pelargonic acid was effective in thinning in apple when applied at a rate of 0.187% at 60% bloom and again at full-bloom. Return bloom in apple was better when blossom thinners effectively thinned blossoms. Dormex application at a rate of 0.31% at full-bloom showed the highest return bloom in apple. All three chemicals were effective in thinning in peach when they were applied before complete fertilization. However, only 0.31% Dormex application at full-bloom was effective in thinning peach when a high rate of fertilization had taken place.
Effects of Application Conditions and Adjuvants on Chemical Fruit Thinning of Apple
Authors: Stover E.W. , Fargione M.J. , Risio R.A. , Mulvihill C.I.
Published: February 2019

In 1995, effects of adjuvants on fruit thinning with Accel [10:1 ratio of 6-benzyladenenine (BA):GA4&7] at 75 ppm BA were studied. Silwet L-77 was used at 0.027% (v/v). Regulaid and ultrafine spray oil were used at 0.125% (v/v). Treatments also included unthinned controls, NAA (naphthalene acetic acid) at 7.5 ppm plus 600 ppm carbaryl, and Accel plus 600 ppm carbaryl. `Empire' apple trees on M.9/MM.111 rootstock in Milton, N.Y., were used in the 6th leaf. Trees were blocked by number of blossom clusters/cm2 trunk cross sectional area. Applications were made at 1.5x concentration, using tree-row volume to calculate appropriate dilute volume. Each spray treatment was applied near the high temperature on each of three consecutive days around 10-mm king fruitlet diameter. Conditions were as follows: day 1–high temperature of 19°C with moderate drying time, and rain several hours after application; day 2–high temperature of 15.5°C and prolonged drying; and day-3–high temperature of 21.1°C and moderate drying. All treatments significantly thinned and enhanced fruit size compared to unthinned controls. Application conditions (treatment day) did not significantly affect response when compared within any spray treatment. However, in combined analyses, treatment with Accel or Accel with Regulaid resulted in significantly smaller fruit on day 1, when rain followed application, compared to these treatments on other days, or compared to Accel with other adjuvants on day 1. Accel with carbaryl resulted in largest fruit size and cropload reduction, but significantly reduced seed number/fruit. It is postulated that prolonged drying times occurring in cool conditions can compensate for reduced uptake rate at lower temperatures.
Enhancement of Transcuticular Penetration of NAA with Ammonium Nitrate and Triton × Surfactants as Spray Additives
Authors: Fader Royal G. , Bukovac Martin J.
Published: February 2019

The plant cuticle is the prime barrier to penetration of foliar-applied plant growth regulators (PGR). Spray additives of various chemistries are frequently included in a tank mix to increase performance of PGRs. We have reported that urea and ammonium nitrate (AN) enhance transcuticular penetration of 14C-labeled NAA (pKa 4.2) from aqueous droplets (pH 5.2) and their subsequent deposits through enzymatically isolated tomato fruit cuticular membranes (CM). Studies on effects of Triton × surfactants on AN-enhanced NAA penetration showed an additional 25% increase in NAA penetration and the AN:surfactant interaction was significant. Also, some alkylamine hydrochlorides increased NAA penetration. Studies comparing NAA penetration through tomato and pepper fruit and Citrus leaf CM in the presence of 8 mM AN or 8 mM ethylamine HCl showed that all three species exhibited the same trend for penetration at 120 h: ethylamine HCl > AN > NAA only. Comparative NAA penetration for CM of the three species was pepper > Citrus > tomato, with significant differences (P > 0.006) in NAA penetration, as indexed by initial slope and penetration after 120 h. On addition of AN, NAA penetration was greater (range 3% to 40%) for Citrus and pepper CM than tomato CM. When ethylamine HCl was added, NAA penetration through Citrus and pepper CM was less (–37 and –27%, respectively) than tomato CM as measured by the initial slope, but 6% and 11%, respectively, more than tomato CM for penetration after 120 h. The differences in NAA penetration among the three species cannot be explained by cuticle thickness, since pepper and tomato CM are 2.5- to 3.5-fold thicker than Citrus CM. We have suggested that the enhanced NAA penetration mediated by AN and ethylamine HCl (and other alkylamine HCl examined) may be related to their hygroscopic properties leading to greater deposit hydration. The significance of the differences among the species CM and surfactant-enhanced NAA penetration will be discussed, in relation to diffusion in the non-living, non-metabolic plant cuticle.
Increased Plant Density and Shade Affects Flowering and Fruiting of Pumpkin (C. pepo)
Authors: Nyankanga R.O. , Wien H.C.
Published: February 2019

Increase in plant density often results in reduction in reproductive potential of individual plants in cucurbits. The reduction may be due to reduced female flower production or a reduction or a delay in fruit set or to decreased fruit size. To determine the cause of the reduction, flowering, and fruiting of two pumpkin cultivars was evaluated in four field experiments under four plant densities ranging from 4483 plants/ha to 23,910 plants/ha and in a greenhouse using three levels of shade. Weekly flower and flower bud counts were made in the field experiment starting at first anthesis. Flowers were determined to have either set or aborted or not have reached anthesis. Increasing plant population from 4483 plants/ha to 23,910 plants/ha resulted in an increase in number of flowers per unit area up to 11,955 plants/ha, beyond which there was a steep decline. Increased plant density also resulted in an increase in aborted female flower buds that did not reach anthesis. Increase in plant density only reduced fruit set at very high populations. Number of fruits per area increased linearly with plant density up to 11,955 plants/ha, but decreased at higher plant populations. Reducing incident light by 30%, 60%, and 80% in a greenhouse experiment resulted in reduction of both male and female flowers. At 80% shade, there was a complete suppression of female flowers, whereas male flowers were still being produced. The number of female flowers reaching anthesis was positively correlated with total shoot dry weight while floral buds and male flowers were not. Reduction of individual plant biomass under high-density plantings might therefore be limiting female flower production and yield.
Differential Control of Embryo Growth Potential in Lettuce and Tomato Seeds
Authors: Hacisalihoglu Gokhan , Khan Anwar A.
Published: February 2019

The effects of chemical or physical factors during pregermination imbibition phase, or on dry seeds, on embryo growth potential (EGP) was studied in lettuce (Grand Rapids and Mesa 659) and tomato (H-9889) seeds in relation to dormancy, invigoration, and vigor loss. Embryos were excised from treated seeds (washed if imbibed in chemical solutions) and their growth rate (a measure of EGP) followed at 25°C at high magnification (X55). Treated seeds were also germinated at 25°C. In lettuce seeds, dormancy inducing treatments, i.e., a 2-day dark soak at 25°C with 50–100 μM tetcyclacis (TCY) or a 2-day dark soak in water at 35°C, reduced the subsequent embryo growth and germination rate at 25°C. The reduction was prevented by 1 mM GA4+7 or irradiation applied during dormancy induction. A -d osmoconditioning (OC) at 15C with -1.2 MPa PEG-8000 solution in light or in dark with added GA4+7 enhanced the EGP; addition of TCY reduced the EGP and the TCY inhibition reversed by GA4+7. A progressive reduction in EGP occurred with increase in vigor loss. In tomato seeds, a soak with 100 μM TCY in light or dark for 2 days at 30°C induced a dormancy, but had little effect on EGP. Application of GA4+7 plus TCY prevented dormancy induction without affecting EGP. A 4-day matriconditioning (MC) at 25°C in light or dark with moist Micro-Cel E enhanced the EGP; TCY and/or GA added during MC, had little effect on EGP. EGP progressively decreased as the aging period increased. Thus, in lettuce, the EGP is coupled with the reversible –GA/+GA or phytochrome-controlled dormancy induction/release process, enabling germination, its inhibition, or its enhancement. In tomato, the EGP is not subject to light or GA control. Reduction in EGP, accompanying vigor loss in both seeds, is independent of light or GA action.
An Internship Program in a Diverse Horticulture Curriculum
Authors: Hughes Harrison
Published: February 2019

Internship credit has been offered for nearly 30 years. In more recent years, it has been formalized with specific guidelines developed in setting up an individual student program. Internship opportunities are facilitated through a career day, which has moved from fall to spring semester in which over 25 firms come on campus to present their opportunities. A detailed packet of information is distributed to the perspective intern and cooperator. A memorandum of agreement is developed with student, cooperator and internship coordinator which details credit, description of the program and hourly wage. Students are required to submit weekly reports and upon returning to campus must present an oral report to a student group and a written report to the internship coordinator. The cooperator does a summary evaluation, which is submitted to the coordinator. A final interview with each student is done with the internship coordinator and a S/F grade is assigned.
Effect of Elevated Root-zone Temperature on Tuber Initiation in Potato cv. Norland
Authors: Stutte G.W. , Yorio N.C. , Mackowiak C.L. , Wheeler R.M.
Published: February 2019

This experiment was performed to test the hypothesis that tuber formation in potato is inhibited by short-term increases in root-zone temperature. Micro-propagated potato cv. Norland plantlets were grown in recirculating nutrient film culture under daylight fluorescent lamps at 350 μmol·m–2·s–1 PPF with at 20/16°C thermocycle at 1200 μmol·mol–1 CO2 under inductive (12-hr light/12-hr dark) or non-inductive (12-hr light/12-hr dark with a 15-min light break 6 hr into the cycle) photoperiods for 42 days. Root-zone treatments consisted of continuous 18°C, continuous 24°C, 18°C with a 24°C cycle between 14 and 21 DAP (prior to tuber initiation), and 18°C with a 24°C cycle between 21 and 28 DAP (during the period of tuber initiation). The root-zone temperature was maintained with a recirculating, temperature-controlled, heat-exchange coil submerged in each nutrient solution. Warm root-zone temperatures did not inhibit tuber formation under an inductive photoperiod. The non-inductive photoperiod resulted in a 65% reduction in tuber biomass compared to the inductive photoperiod. Continuous 24°C and exposure to 24°C prior to tuber initiation reduced tuber formation an additional 40% under the non-inductive photoperiod. Both continuous and transient 24°C root-zone temperatures increased biomass partitioning to root/stolons compared to the 18°C treatment under both photoperiods. Total plant biomass was highest in plants exposed to continuous 24°C under both photoperiods. Results suggest that transient episodes of warm (24°C) root-zone temperature do not inhibit tuber formation in potato under inductive photoperiods. However, transient episodes of warm (24°C) root-zone temperatures did interact with stage of development under the non-inductive photoperiod.
Early Growth and Development of Pawpaw [Asimina triloba (L.) Dunal] Seedlings in the Greenhouse as Influenced by Shade and Root-zone Modification
Authors: Layne Desmond R. , Peters L.N.
Published: February 2019

This experiment was designed to determine the optimal light level for growing pawpaw seedlings in the greenhouse. In addition, we wanted to determine if modifying the root-zone would positively impact pawpaw seedling growth and development. Experimental treatments were imposed from seed sowing until the plants were destructively harvested. The experimental design was a split-plot, where blocking was done by position in the greenhouse. The main plot of the experiment was shade. This was accomplished by growing seedlings under a wooden frame covered with shadecloth to reduce incident light intensity received by the plant by 30%, 55%, 80%, or 95%. The control treatment was 0% shade or ambient greenhouse light level. The split-plot was root-zone modification. Half of all growing containers were untreated (control) while the other half were painted with SpinOut™, a commercially available product used to reduce root spiraling in nursery containers. There were 40 replicate seedlings per experimental treatment combination per block. Seedling shoot length and unfolded leaf number was recorded twice a week from seedling emergence until destructive harvest. Whole-plant leaf area was also determined. Leaves, stems, and tap and lateral roots were separated and dried to determine biomass partitioned to the respective organs. Up to 55% shade did not significantly reduce whole-plant biomass, while plants at 80% and 95% shade were stunted. Shade in the greenhouse is not required as was previously thought. Specific leaf mass and lateral root mass decreased as shade increased. Neither tap or lateral root dry weights were significantly affected by root-zone modification. New recommendations for container production of pawpaws in the greenhouse will be discussed.
Ebb-and-flow Irrigation in Bedding Plant Production
Authors: James Erin , van Iersel Marc
Published: February 2019

The negative effects of nutrient runoff on the environment has come more to the forefront of greenhouse issues in the past few years. Alternative irrigation systems that reduce or eliminate runoff that are widely used in Europe have not yet gained much popularity in the southeastern United States, in part due to a lack of available information on their use. One such system is ebb-and-fl ow, which is a completely closed recirculating system, having no runoff whatsoever. In order to learn more about optimum growing practices using the ebb-and-fl ow system for bedding plants, marigolds and sunflowers were grown under a variety of conditions. After a 6-week period, pH of growing media of both marigolds and sunflowers decreased by 1, while EC increased by ≈1 dS/m. There were also significant differences in EC due to the different media types. The soilless medium with the highest percentage of vermiculite and lowest percentage of pine bark had the highest EC. Different types of fertilizer and fertilizer rates will be discussed, as well as interactions between fertilizer and media.
Comparison of Three Sprinkler Designs for Cold Protection in Shadehouses
Authors: Stamps Robert H.
Published: February 2019

Water is an economical source of heat to prevent cold damage to certain crops; however, ways to reduce the quantity of this limited resource required for cold protection need to be developed. Rapidly rotating (6 rpm) wedge-drive impact sprinklers (conventional practice) were compared with a rotary action spray head and patented slow-rotating stream sprinklers for cold-protecting a subtropical crop {leatherleaf fern [Rumohra adiantiformis (Forst.) Ching]} growing in shadehouses. Treatments were applied in a 3 × 3 latin square design to nine 29 × 29-m post- and-cable shadehouses covered with woven polypropylene shade fabric designed to provide 73% shade. Temperatures in each shadehouse were monitored 45 cm above the soil surface using four constantan–copper thermocouples. Ambient temperatures and wind speeds were monitored using additional thermocouples and an anemometer at a nearby weather station. All sprinklers had 2.8-mm orifices, were operated at 0.25 Pa, and applied 0.5 (rotating stream, rotary) or 0.54 (wedge-drive) cm·hr–1 of water. During an advective freeze with windspeeds up to 19 m·s–1 and temperatures to –2°C, there were no temperature differences due to treatments. During a radiational freeze with readings below –2°C for over 12 hr and a low of –5°C, all three irrigation systems maintained thermocouples at about –1°C. No significant damage to mature fronds were detected. Percentage of immature fronds damaged was not affected by treatments and ranged from 11% for rotary to 43% for the wedge-drive sprinkler treatments. The two newer sprinkler designs (rotary action spray head and patented slow-rotating stream) provided satisfactory protection equivalent to the industry standard (wedge-drive) while using about 10% less water.