bluuebunny/crossref_metadata_2025 huggingface dataset:
MODIFICATION OF A MODEL PREDICTING ROSE FLOWER GROWTH UNDER DIFFERENT IRRADIANCE REGIMES
Authors: Hopper Douglas A. , Woerner Steven E.
Published: February 2019

Three-year-old Rosa hybrida L. `Royalty' and `Red Success' plants were pinched 20 Oct. and 22 Dec. 1990 to time production for Christmas and Valentine's Day, respectively. Two greenhouses received ambient solar radiation while two additional houses had 50% reduction in irradiance using a shading thermal blanket. All temperature set points were 23C/17C day/night. Every 10 days and at flowering shoots were measured for leaf (node) number, stem diameter, stem length, and fresh weights of stem, leaves, and flower bud. Time to visible bud and to flowering from pinch were recorded.

A computer model, ROSESIM, had been formulated in SLAM II and converted to both FORTRAN and BASIC code to make the program more portable. Although ROSESIM closely predicted `Royalty' fresh weights when irradiance was high before Christmas, underprediction occurred in the lower irradiance before Valentine's Day, and time to flowering was predicted earlier than was observed under all conditions. Corrective coefficients were added to ROSESIM to improve accuracy of prediction under actual greenhouse conditions.
THIDIAZURON: A POTENT GROWTH REGULATOR FOR INDUCING HIGH-FREQUENCY ORGANOGENESIS AND SOMATIC EMBRYOGENESIS IN VITRO
Authors: Malik K.A. , Visser Christena , saxena praveen K.
Published: February 2019

In vitro regeneration by shoot organogenesis and-or somatic embryogenesis is accomplished by culturing the explants on a nutrient medium supplemented with phytohormones. Auxins in general, and 2,4-D in particular, have been shown to induce somatic embryogenesis whereas shoot regeneration is stimulated by cytokinins. In studying the morphoregulatory role of thidiazuron (TDZ) - a substituted urea with cytokinin-like activity - we found that it induces a high frequency of both organogenesis and somatic embryogenesis depending upon the plant species. For instance, whole seedlings of peanut developed somatic embryos and those of bean and pea produced shoots in response to culture on TDZ (1-40 μM)-supplemented media. In cultured explants of geranium, the use of TDZ (0.2-1 μM) effectively replaced the requirement of 2,4-D or BAP and IAA for obtaining somatic embryos. The frequency of regeneration was two to ten times higher than that achieved with auxin-cytokinin combinations. While no direct evidence is currently available to establish a relationship between TDZ and endogenous phytohormones, our results suggest that it may act by establishing endogenously the auxin:cytokinin ratio permissive of induction and expression of morphogenically competent cells.
CRYOGENICS AND TISSUE CULTURE FOR PRESERVING PECAN GERMPLASM
Authors: Abou Taleb S. , Yates I. , Wood B.W. , Fouad M.M.
Published: February 2019

A study was conducted to develop protocol for the preservation of pecan genetic variability by cryogenic storage of zygotic embryos and subsequent in vitro plant regeneration. Parameters evaluated for their influence on embryo survival included the amount of intact kernel, liquid nitrogen (LN) treatment, desiccation, and genotype specificity. Optimum germination with minimum contamination occurred with 12% of the kernel intact. Treatment of explants with LN reduced the percentage of embryos developing into intact plants. `Curtis' and `Shoshoni' had a significantly higher morphogenic response in shoots only than all other cultivars. In summary, cryogenic storage of pecan zygotic embryos was determined to be a feasible means for preservation of pecan germplasm. However, the procedures used in the current study should be altered to increase the probability of embryo survival.
INDUCTION AND MORPHOLOGICAL CHARACTERISTICS ASSOCIATED WITH EMBRYOGENESIS OF OENANTHE STOLONIFERA DC.
Authors: Lee Ji-Weon , Lee Byoung-Yil
Published: February 2019

The study was carried out to examine the appropriate media, explant sources, and suitable growth regulators for somatic embryogenesis to establish a rapid mass production system via somatic embryogenesis in Oenanthe stolonifera DC. Modified MS media containing higher concentrations of NO3-N were more effective for the formation and development of the somatic embryos from embryogenic callus. Liquid media were more effective for the production of somatic embryos than solidified media. Immature florets were found to be the most competent explant sources for embryogenic callus formation. 2,4-D at 1mg/l was highly effective for the formation of embryogenic callus but inhibitory for the development and differentiation of somatic embryo. Somatic embryos were developed from the translucent and friable embryogenic callus. Addition of BA promoted the callus growth synefgistically with NAA and 2,4-D, but the production of embryogenic callus was inhibited by BA.
THE EFFECT OF CECROPIN B ON CELLS AND PROTOPLASTS OF PEACH
Authors: Mills David , Hammerschlag Freddi A.
Published: February 2019

Pathogenic bacteria, such as Xanthomonas campestris pv. pruni, cause diseases of significant economical implications in the Prunus genus. Cecropins are naturally occurring bactericidal peptides found in the hemolymph of insects. Cecropins cause channel formation in membranes and lysis of bacterial cells. We are interested in engineering the gene for cecropin into peach (Prunus persica) and other fruit tree species. The objective of this study was to determine the effect of cecropin B on viability, using fluorescein diacetate staining, and on changes in transmembrane electrical potential (PD) using the fluorescing probe merocyanine-540. Protoplasts were isolated from shoot-tip cultures in a CPW13M (salts + 0.71M mannitol) solution containing 2% cellulase and 0.5% macerase, while cells were isolated in CPW15.4S (salts + 0.45M sucrose) containing 0.5% cellulase and 0.5% macerase. Cecropin B (1μM) had no effect on viability and changes in PD, while 10μM had a slight effect, and 100μM cecropin B caused significant depolarization and lysis of peach protoplasts. No effect on viability and change in PD were observed in cells when treated with 1-100μM cecropin B. These results suggest that cells and protoplasts of peach can resist cecropin B in the concentration range that causes lysis of plant pathogenic bacteria. The implication of using cecropin to increase microbial disease resistance will be discussed.
IN VITRO FLOWERING OF MINIATURE ROSE CULTIVARS
Authors: Kane Michael , Philman Nancy L. , Marousky Francis J.
Published: February 2019

Premature deterioration and/or wilting of cut flowers such as roses (“bent neck”) has been attributed to vascular blockage within the cut stem. Vascular blockage has been attributed to both the proliferation of bacteria in the cut flower water and/or to products exuded by the stem. Separation of these causative agents is prevented by the inability to obtain intact microbe-free flowers. With the objective to produce microbe-free flowers, 36 miniature rose cultivars were screened for their capacity to flower in vitro. Stem segments containing single lateral buds were surface sterilized in 1.05% (v/v) sodium hypochlorite and rinsed three times in sterile distilled deionized water. Buds were established on medium consisting of Murashige and Skoog mineral salts, Woody Plant Medium organics, 3.0% (w/v) sucrose, 0.5 mg/liter benzyladenine, 0.1 mg/liter indole-3-acetic acid, and 50 mg/liter each citric and ascorbic acids. Medium was solidified with 1.5 g/liter gelrite and 4 g/liter TC® agar. Of the 36 cultivars screened, eight (22%) grew poorly in vitro. Of the 28 responsive cultivars, 14 (50%) produced flower buds in vitro However, only six cultivars produced open flowers in vitro.
CRYOPRESERVATION OF ALGINATE-COATED IN-VITRO-GROWN SHOOT TIPS OF APPLE
Authors: Niino T. , Sakai A.
Published: February 2019

In-vitro-grown shoot tips of apple (Malus domestia Borkh cv. Fuji) were successfully cryopreserved by dehydration of alginate-coated shoot tip. Cold-hardened shoot tips (at 5°C for 3 weeks) were precultured on a medium containing increasing concentrations of sucrose. The shoot tips were trapped into alginate coated beads containing 0.5M sucrose followed by preculture in a medium supplemented with 1.0M sucrose. Beads containing 1 shoot tip were dehydrated up to about 32% on sterile dry silica gel at 25°C followed by a plunge in LN. After rapid warming, approximately 80% shoot formation was achieved. This encapsulation-dehydration technique may permit strage of shoot tips at higher temperatures than that of LN.
SHOOT GROWTH AND PROLIFERATION OF PEACH UNDER VARYING ENVIRONMENTAL REGIMES.
Authors: Zimmerman Thomas W. , Scorza Ralph
Published: February 2019

This study examined stage I peach shoot growth under various photoperiods in combination with different vessel closures and compared the influence of BA and Thidiazuron (TDZ) on peach shoot growth during stage II. The basal salts were as described by Almehdi and Parfitt (1986) with 1.0 μM BA, 0.02 μM IBA, 2% sucrose, 0.1% gelrite and 0.4% agar. Shoot growth of peach clone B612615, as determined by leaf number after one month, was similar in vessels capped with Kim-Kaps, Kaputs or PM caps. Plastic foam Identi-Plugs resulted in desiccation of the medium and stressed shoots with reduced growth. A 4 h light/2 h dark photoperiod four times a day provided better growth during stage I than a 16 h light/ 8 h dark photoperiod. For stage II, established shoots of Suncrest, Georgia Bell and Evergreen were grown on MS medium supplemented with 0.02 μM IBA in combination with 1.0 or 10 μM BA or 0.1, 1.0 or 10 μM TDZ. TDZ produced excessive callus resulting in minimal shoot proliferation. Shoot proliferation from axillary buds was greatest with 10 μM BA.
EFFECT OF LIGHT, CO2, AND SUCROSE CONCENTRATIONS ON THE IN VITRO GROWTH OF WHITE POTATO (SOLANUM TUBEROSUM L.)
Authors: Yorio N.C. , Wheeler R.M. , Weigel R.C.
Published: February 2019

Growth measurements of potato (Solanum tuberosum L.) cvs. Norland (NL), Denali (DN), and Kennebec (KN) were taken from 21-day-old plantlets grown in vitro. Studies were conducted in a growth chamber, with nodal explants grown in culture tubes with loose-fitted Magenta 2-way caps containing Murashige and Skoog salts with either 0, 1, 2 or 3% sucrose. The cultures received either 100 or 300 μmol m-2 s-1 photosynthetic photon flux (PPF), and the growth chamber was maintained at either 400 or 4000 μmol mol-1 CO2. All cvs. showed significant increases in growth on 0% sucrose media at 4000 μmol mol-1 CO2, indicating an autotrophic response. At 400 μmol mol-1 CO2, all cvs. showed an increase in total plantlet dry weight (DW) with increasing sucrose under both PPF levels. Within any sucrose treatment, the highest total DW for all cvs. resulted from 300 μmol m-2 s-1 PPF and 4000 μmol mol-1 CO2. At 4000 μmol mol-1 CO2, shoot DW declined with sucrose above 2% for DN and sucrose above 1% for NL at both PPF levels, suggesting that high sucrose levels may hinder growth when CO2 enrichment is used.
THE USE OF IN VITRO MIST CULTIVATION FOR THE PROPAGATION AND HARDENING-OFF OF VIRUS-FREE POTATO PLANTLETS.
Authors: Giles Kenneth L. , Friesen Kenneth , Novakovski Debra
Published: February 2019

The use of an in vitro mist culture systems for the growth of virus free shoots of several potato cultivars has been demonstrated using the “Mystifier®”, several different media and growth regulator concentrations have been used to monitor the efficiency of shoot multiplication and growth. Nodal cuttings of sterile in vitro virus free cultures were used as inocula and the mist was applied at various rates in order to assess optimum sucrose concentrations and mineral concentrations. Murashige and Skoog medium was used and diluted to half and quarter strength.

Hardening off the resulting shoots was achieved by passing HEPA filtered air at various rates over the plantlets still in the culture vessel. Conditions for high efficiency hardening off of cultured material has been defined such that plantlets can be transferred directly to greenhouse conditions.

The implications and opportunities that are indicated by this work are discussed.
AN IN VITRO TISSUE CULTURE TECHNIQUE FOR EVALUATING SUSCEPTIBILITY TO NEMATODE AND TOLERANCE TO HEAT STRESS IN TOMATOES
Authors: Abdul-Baki Aref A. , Haroon S. A. , Huettel R. N.
Published: February 2019

Susceptibility of tomato (Lycopersicon esculentum Mill) genotpyes to the root-knot nematode Meloydogyne incognita and to heat stress can be evaluated in a single labor- and time-saving operation using a nondestructive in vitro excised root technique. Seeds are sterilized and germinated for 2 days on 1% water agar. Five-mm root sections are grown at 28 and 35 C for 30 days on Gamborg-B medium with and without nematode inoculum. Evaluation criteria include fresh and dry weight and the appearance of juveniles, adults, gulls, and egg masses. Evidence will be presented on the breakdown of resistance to M. incognita under high temperature stress.
Growth Response of One-year-old `Granny Smith' Apple Branches in Relation to Time of Heading
Authors: Oosthuyse S.A. , Jacobs G. , Strydom D.K.
Published: February 2019

Upright l-year-old apple (Malus domestica Borkh. `Granny Smith') branches were headed at 14-day intervals (branches headed once each) during late winter and in spring [70 days before full-bloom (DBFB) until 28 days after full-bloom (DAFB)] and budbreak and new shoot growth quantified on the remaining branch section after cessation of these events. When heading was performed 70, 56, or 42 DBFB, four to five buds broke on average. When branches were headed subsequently, the average number of buds breaking increased progressively, then decreased with heading date, the maximum number breaking (13) on branches headed 14 DAFB. An average of 10 or 11 buds broke per branch section when heading was performed 28 DAFB. In late summer, the total length of new shoots per branch section for the branches headed before full bloom averaged 113 cm, whereas that on the branches headed at or after full-bloom averaged 76 cm.
Sodium Hypochlorite Concentration, Temperature, and Seed Age Influence Germination of Sweet Pepper
Authors: Khah E.M. , Passam H.C.
Published: February 2019

The effects of NaOCl on the germination behavior of seeds of sweet pepper (Capsicum annuum L. cv. E-84066) were related to the concentration of NaOCl, treatment duration, solution temperature during treatment, incubation temperature during germination, and the age of the seed. Rate and percentage of germination were slower and lower, respectively, when seeds were exposed to 3% NaOCl solution at 35C for 20 or 40 min. When treatment time and temperature were reduced, or the NaOCl concentration lowered, the adverse effects were less. Fresh seeds were more sensitive than seeds that had been stored for 10 months at ambient temperature, and inhibition of germination was greater when the incubation temperature during germination was lower or higher (15 or 35C) than the optimum (25C).
Distinguishing Apple Rootstocks by Isozyme Banding Patterns
Authors: Samimy Cyrus , Cummins James N.
Published: February 2019

Isozymes of six enzyme systems extracted from 13 apple (Malus domestica Borkh.) rootstocks were separated electrophoretically on a horizontal starch gel. Each rootstock was clearly distinguished by its unique isozyme banding patterns. All the rootstocks were distinguishable using only two of the enzyme systems, phosphoglucomutase and 6-phosphogluconate dehydrogenase, both of which exhibited considerable isozyme polymorphism.
Hydrogen Cyanamide-induced Budbreak and Phytotoxicity in `Redhaven' Peach Buds
Authors: Siller-Cepeda Jorge H. , Fuchigami Leslie H. , Chen Tony H.H.
Published: February 2019

The effects of hydrogen cyanamide (H2CN2) on budbreak and phytotoxicity of l-year-old potted peach trees [Prunus persica (L.) Batsch. cv. Redhaven] over a wide range of concentrations at several stages of dormancy were studied. Endodormancy (180° GS; degree growth stage) began on 1 Oct. Maximum intensity of endodormancy (270° GS) was reached after the plants were exposed to 320 chill units on 1 Nov., and 50% of the buds were broken at 860 chill units on 1 Dec. Five concentrations of H2C N2 (0, 0.125, 0.25, 0.5, and 1.0 m) were applied on 1 and 15 Oct., 1 and 15 Nov., and 1 and 15 Dec. 1990. All concentrations promoted budbreak; however, percent budbreak and phytotoxicity depended on concentration and timing of application. The most effective concentration (greatest budbreak and lowest phytotoxicity) was 0.125 m H2CN2 on all treatment dates. Phytotoxicity was evident at all application dates but was greatest at the highest concentrations. Plants were most resistant to H2CN2 at maximum intensity of endodormancy. Hydrogen cyanamide-induced budbreak was highest during the later stages of endodormancy (295 to 315° GS). Treatments applied during the ecodormancy stage (340° GS) inhibited and delayed budbreak and damaged buds and stems. Chemical name used: hydrogen cyanamide (H2CN2, Dormex).
Rosetting of Lisianthus Cultivars Exposed to High Temperature
Authors: Harbaugh Brent K. , Roh Mark S. , Lawson Roger H. , Pemberton Brent
Published: February 2019

Three lisianthus [Eustoma grandiflorum (Raf.) Shinn.] cultivars 0, 10, 17, 24, or 31 days from sowing were grown in 28C soil for 0, 7, 14, 21, or 28 days to determine the effects of high temperature during seedling growth on the development of rosetted plants. Increasing the duration of high-temperature exposure increased the percentage of rosetted plants for all cultivars. Such exposure for 28 days resulted in 96%, 93%, and 18% rosetted plants for cultivars Yodel White, Yodel Pink, and GCREC-Blue, respectively. Seedling age did not affect percentage of flowering `Yodel Pink' plants, but as seedling age increased to 31 days, the percentage of flowering plants increased with `GCREC-Blue' and decreased for `Yodel White'. In a second experiment, four lisianthus cultivars were grown at 22C for 3 weeks and then exposed for 28 days to soil at 22, 25, 28, or 31C. Increasing soil temperature resulted in more rosetted plants for all cultivars. With soil at 31C, 83%, 58%, 19%, and 2% of the seedlings rosetted for the cultivars USDA-Pink, Yodel White, Little Belle Blue, and GCREC-Blue, respectively.
Buffalograss Tolerance to Postemergence Herbicides
Authors: McCarty Lambert B. , Colvin Daniel L.
Published: February 2019

Buffalograss [Buchloe dactyloides (Nutt.) Engelm.] is a turfgrass species traditionally adapted to low-rainfall areas that may incur unacceptable weed encroachment when grown in higher rainfall areas such as Florida. An experiment was performed to evaluate the tolerance of two new buffalograss cultivars, `Oasis' and `Prairie', to postemergence herbicides commonly used for grass, broadleaf, and sedge weed control. Twenty to 40 days were required for each cultivar to recover from treatment with asulam, MSMA, and sethoxydim (2.24, 2.24, and 0.56 kg-ha-l, respectively). Other herbicides used for postemergence grass weed control (metsulfuron, quinclorac, and diclofop at 0.017, 0.56, and 1.12 kg·ha-1, respectively) did not cause unacceptable buffalograss injury. Herbicides used for postemergence broadleaf weed control, triclopyr, 2,4-D, sulfometuron, dicamba (0.56, 1.12, 0.017, and 0.56 kg·ha-1, respectively), and a three-way combination of 2,4-D + dicamba + mecoprop (1.2 + 0.54 + 0.13 kg·ha-1), caused 20 to 30 days of unacceptable or marginally acceptable turfgrass quality, while 20 days were required for `Prairie' buffalograss to recover from atrazine treatments. `Oasis' buffalograss did not fully recover from 2,4-D or 2,4-D + dicamba + mecoprop through 40 days after treatment. Herbicides used for postemergence sedge control, bentazon and imazaquin, caused slightly reduced, but acceptable, levels of turf quality in both cultivars throughout the experiment. Chemical names used: 6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine (atrazine); methyl[(4-aminophenyl)sulfonyl]carhamate (asulam); 3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide (bentazon); 3,6-dichloro-2-methoxybenzoic acid (dicamba); (±)-2-[4-(2,4-dichlorophenoxy)phenoxy]propanoic acid (diclofop); 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid (imazaquin); (±)-2-(4-chloro-2-methylphenoxy)propanoic acid (mecoprop); 2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]benzoic acid (metsulfuron); monosodium salt of methylarsonic acid (MSMA); 2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one(sethoxydim); 2-[[[[(4,6-dimethylethyl-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]benzoic acid (sulfometuron); [(3,5,6-trichloro-2-pyridinyl)oxy]acetic acid (triclopyr); (2,4-dichlorophenoxyl)acetic acid (2,4-D); 3,7-dichloro-8-quinolinecarboxylic acid (quinclorac).
Internal Variation in Peach Fruit Firmness
Authors: Maness Niels O. , Brusewitz Gerald H. , McCollum T. Gregory
Published: February 2019

Variability in mesocarp firmness for peach (Prunus persica L. Batsch) fruit halves cut either parallel or perpendicular to the suture was determined for three cultivars (Halehaven, Ranger, and Topaz). Firmness evaluations were conducted using an Instron Universal testing instrument with a 3.2-mm rounded tip probe. Firmness of the inner, middle, and outer regions of the mesocarp at four angular positions around each peach half was determined at four maturity stages. Average mesocarp firmness declined with advanced stages of fruit maturity. Inner mesocarp was firmest for fruit from all three cultivars. Internal variation in firmness for the middle and outer regions of the mesocarp was highly cultivar dependent. Firmness decreased longitudinally from the stem end to the blossom end and latitudinally from the suture to the cheeks.
Screening for Salt Tolerance in Melons
Authors: Mendlinger Samuel , Pasternak Dov
Published: February 2019

Twenty melon (Cucumis melo L.) cultigens (cultivars and breeding lines) were tested for salt tolerance. All cultigens were grown in the field using drip irrigation at three salt salinity levels: electrical conductivity (ECw = 1.2, 7.5, or 14.0 dS·m-1. Nineteen of the 20 cultigens proved to be salt-sensitive, as measured by reduction in fruit weight, but not necessarily to the same degree (i.e., some cultigens were tolerant at ECw = 7.5, whereas others were not). One line, `Evan Key', was salt-tolerant at ECw= 14.0. Increasing salinity levels did not affect the number of fruits produced in most cultigens. Overall, increasing salinity reduced netting quality but increased the total soluble solids content and shortened mean time to harvest in seven cultigens.
Clip-and-wash Method of Emasculation for Lettuce
Authors: Nagata R.T.
Published: February 2019

Complete (100%) hybridization in lettuce (Lactuca sativa L.) was accomplished consistently using the clip-and-wash method of emasculation. The clip-and-wash method is a combination of washing and clipping, two previously described procedures for pollen removal. The wash and the clip methods produced 98% and 95% hybridization, respectively. The method is quick and easy and eliminates inadvertent self pollination; with it one can produce the many hybrid seeds necessary for backcross and F1 genetic analysis in lettuce.
A Decision Support System for Apple Thinning in Colorado
Authors: Rogoyski Matthew K. , Renquist A. Richard
Published: February 2019

A decision support system has been developed to help Colorado fruit growers with apple (Malus domestica Borkh.) thinning. This system can also be used as a teaching aid and as a tool for generating research hypotheses. The system determines if fruit thinning is needed by identifying catastrophic events that would eliminate the need for thinning. The major function of this decision support system is determination of tree responsiveness to chemical thinning agents. This is accomplished through analysis of the user's answers to questions related to the physiological status of the trees, environmental data, bearing history, and the apple variety in question. On the basis of the above analysis, two sets of recommendations are presented: general recommendations based on the variety selected, and specific ones for that variety based on growth stage and tree responsiveness to thinners. The user also is provided with the rationale for the recommendations.
Smooth Crabgrass Control in Perennial Ryegrass with Repeated Low Fenoxaprop Application Rates
Authors: Demoeden P.H. , Mahoney M.J. , Carroll M.J.
Published: February 2019

Fenoxaprop (0.027, 0.036, and 0.045 kg·ha-1) was field-applied at either of 2-, 3-, or 4-week intervals to perennial ryegrass (Lolium perenne L.) naturally infested with smooth crabgrass [Digitaria ischaemum (Schreb.) Muhl.] in Maryland (Easton and Silver Spring) during 1989 and 1990. In 1989, fenoxaprop applied at 2- or 3-week intervals at 0.027 kg·ha-1 provided fair (>74%) to good (>80%) smooth crabgrass control. Fenoxaprop applied at 0.036 or 0.045 kg·ha-1 at 2- or 3week intervals provided good to excellent (> 90%) smooth crabgrass control. Four-week intervals generally provided control that was inferior to the shorter application intervals at Silver Spring but not at Easton. In 1990, all rates provided good to excellent smooth crabgrass control when applied at 2- or 3-week intervals in Easton. At Silver Spring, where smooth crabgrass levels were very high, >88% control was provided by 0.036 kg·ha-1 applied at a 2-week interval and by 0.045 kg·ha-1 applied at either a 2- or 3-week interval. Chemical name used: [±]-2-[4-[(6 chloro-2 benzoxazolyl)oxy]phenoxy] propanoic acid (fenoxaprop).
Relationship between Pyruvate Analysis and Flavor Perception for Onion Pungency Determination
Authors: Wall Marisa M. , Corgan Joe N.
Published: February 2019

Individual onion (Allium cepa L.) bulbs were evaluated for pungency by measurement of enzymatically produced pyruvate and by flavor perception. In four separate experiments, pyruvate values were highly and significantly correlated to mean sensory ratings. Correlation coefficients (r) were 0.92, 0.84, 0.95, and 0.79, and regression coefficients (R2) were 0.84, 0.71, 0.91, and 0.62. The high correlations indicate that pyruvate analysis can be used as a reliable selection technique for pungency in onion breeding programs.
Physiological and Growth Responses of St. Augustinegrass Cultivars to Salinity
Authors: Dudeck A.E. , Peacock C.H. , Wildmon J.C.
Published: February 2019

Salt tolerance in grasses is needed due to increased restrictions on limited fresh water resources and to saltwater intrusion into groundwater. St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] is used widely as a lawngrass in states bordering the Gulf of Mexico. We describe the response of four St. Augustinegrass cultivars to solution cultures differentially salinized with synthetic seawater. A sea salt mixture was added to half-strength Hoagland's No. 2 nutrient solution to provide six salinity treatments ranging from 1.1 to 41.5 dS·m-1. Adjustments in leaf water potential, leaf osmotic potential, and leaf turgor potential were measured as salt levels were increased gradually at 2-day intervals over 10 days. Salinity effects on growth of top, crown, and root of each cultivar were measured over 3 months. Turfgrasses differed in their response, but were consistent in adjustment in leaf water potential and in leaf turgor potential as salinity increased. Leaf water potential, leaf osmotic potential, and leaf turgor potential decreased linearly with increased salinity, but a positive turgor of 0.1 MPa was maintained at a salt concentration equal to that of seawater. `Seville', the most salt-tolerant St. Augustinegrass cultivar, exhibited a 50% reduction in top growth at 28.1 dS·m-1, while `Floratam', `Floratine', and `Floralawn' St. Augustinegrasses showed the same reduction in top growth at 22.8 dS·m-1. Differences between cultivars were greatest at salinity levels <10 dS·m-1, where `Seville' was twice as salt-tolerant compared to other cultivars. The grasses did not die, although top growth of all cultivars was severely reduced at a salt level equal to seawater.
Peroxidases of Selected Fruits and Vegetables and the Possible Use of Ascorbic Acid as an Antioxidant
Authors: Préstamo G. , Manzano P.
Published: February 2019

The various isozymes of peroxidase of a range of vegetables and kiwifruit were compared using sodium dodecyl sulfate polyacrylamide gel electrophoresis followed by specific activity staining. Peroxidase isozymes were determined in potato (Solanum tuberosum L.), carrot (Daucus carota L.), tomato (Lycopersicon esculentum Mill.), kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson], cauliflower [Brassica oleracea (Botrytis group)], green beans (Phaseolus vulgaris L.), and horseradish (Armoracia rusticana Gaertn, Mey Scherb.). There was only one isozyme in cauliflower (70 kDa), two in kiwifruit (45-43 kDa), and a range of isozymes (120-36 kDa) in horseradish. Ascorbic acid inhibited peroxidase activity in the extracts.
Somatic Embryogenesis and Plant Regeneration from Muscadine Grape Leaf Explants
Authors: Robacker Carol
Published: February 2019

Immature leaf laminae and petioles of `Regale' and `Fry' muscadine grapes (Vitis rotundifolia Michx.) were cultured on Nitsch and Nitsch (NN) medium supplemented with 9.0 μm 2,4-D and 4.4 μm BA, and gelled with agar. Callus and original explant tissues were transferred to NN medium containing 10.7 μm NAA and 0.9 μm BA to proliferate embryogenic callus, which, when transferred to NN medium without growth regulators, yielded globular embryos. The embryos matured and germinated after being subcultured to fresh medium without growth regulators. Somatic embryogenesis incidence was greater from petioles than laminae: 90% of `Regale' and 50% of `Fry' petioles formed embryos, compared with 14% and 2% of laminae, respectively. Culturing germinated somatic embryos on NN medium with 1 μm BA enhanced shoot growth. Regenerated plants flowered and appeared morphologically normal. Chemical names used: N-(phenylmethyl)- 1H -purin-6-amine (BA); 2,4-dichlorophenoxyacetic acid (2,4-D); α- naphthaleneacetic acid (NAA).
Preculture Medium Promotes Direct Shoot Regeneration from Micropropagated Strawberry Leaf Disks
Authors: Sorvari S. , Ulvinen S. , Hietaranta T. , Hiirsalmi H.
Published: February 2019

The effect of preculturing in vitro plantlets of two strawberry (Fragaria ×ananassa Duch.) cultivars grown on micropropagation medium with and without hormones on regenerating shoots from leaf disks was examined. Preculturing stock plants on micropropagation medium with hormones (BAP at 0.5 mg·liter-1 + IBA at 0.5 mg·liter-1 GA, at 0.2 mg·liter-1) promoted shoot regeneration in the two cultivars tested. Using hormone-containing micropropagation medium for preculture, the highest mean regeneration rate of 9.9 shoots per total number of leaf disks was obtained for the Finnish cultivar Hiku on modified Murashige and Skoog (MS) regeneration medium supplemented with (in mg·liter-1) 2000 KNO3, 400 casein hydrolysate (CH), 3 BAP, and 0.1 IBA. For the Norwegian cultivar Jonsok, the highest mean regeneration rate of 12.8 shoots per total number of leaf disks was obtained on modified MS regeneration medium with (in mg·liter-1) 600 CH, 3 BAP, and 0.1 IBA. Chemical names used: 6-benzylaminopurine (BAP); 3-indolebutyric acid (IBA); gibberellic acid (GA).
Failure of Agrobacterium radiobacter Strain K-84 to Control Crown Gallon Raspberry
Authors: Burr Thomas J. , Reid Cheryl L. , Katz Barbara H. , Tagliati Maria Elisabetta , Bazzi Carlo , Breth Deborah I.
Published: February 2019

Agrobacterium radiobacter (Beijerinc and van Delden) Conn strain K-84 failed to control raspberry (Rubus idaeus L.) crown gall caused by A. tumefaciens (E.F. Smith and Townsend) Conn. Agrobacterium tumefaciens strains isolated from galls on plants that had been treated with K-84 were not sensitive to agrocin 84 in vitro. These strains were isolated from `Titan' and `Hilton' raspberry in New York state and from `Himbo Queen' and `Schönemann' raspberry in Italy. Almost all strains were identified as A. tumefaciens biovar 2. Raspberry crown gall was not controlled by K-84 in three field experiments in New York state. In two of the experiments, plants were produced by micropropagation and were known to be pathogen-free. The other plant source was shown to be contaminated with the pathogen before treatment with K-84. Crown gall was not controlled either on raspberry in a greenhouse experiment or on Kalanchoe diagremintiana (Hamet. and Perrier) plants that were coinoculated with K-84 and strains of A. tumefaciens isolated from galls on raspberry.
Semidwarf Growth Habit in Clingstone Peach with Desirable Tree and Fruit Qualities
Authors: Gradziel T.M. , Beres W.
Published: February 2019

A single seedling exhibiting a semidwarf growth habit was found in an open-pollinated clingstone peach [Prunus persica (L.) Batsch] population. The growth habit was upright and open, with short, spur-like lateral branching. Tree size was about half that of its siblings as a result of shorter internodes. The total number of nodes on first-order branches was not significantly different from that on standard-sized trees. The semidwarf growth habit remained stable after vegetative propagation. Segregation in sexual progeny showed the trait to be highly heritable.
Determining Cold Hardiness of Heuchera sanguinea Engelm. `Chatterbox' Using Dormant Crowns
Authors: Iles Jeffery K. , Agnew Nancy Howard
Published: February 2019

Dormant, intact crowns were used to determine the cold hardiness of the herbaceous perennial Heuchera sanguinea `Chatterbox'. Crowns were placed in moist cheesecloth, wrapped in aluminum foil, and subjected to -4,-6,-8,-10,-12,-14, -16, or -18C in a programmable freezer. Regrowth quality ratings and dry-mass measurement decreased linearly with temperature. No regrowth was evident from any crown exposed to -12C or lower temperatures. Freezing dormant plant crowns proved an efficient and reliable technique for estimating cold hardiness of Heuchera `Chatterbox'.
Planting Methods Affect Early Growth and Root Distribution of Muscadine Vines
Authors: Olien William C. , Hegwood C.P. , Spiers James M.
Published: February 2019

Muscadine (Vitis rotundifolia Michx.) vineyards can be difficult to establish due to poor vine growth or survival during the first year after planting. Effects of the planting hole (five types), root manipulation (three levels), and peat amendment (0% and 50%) on first-year growth were studied at two sites with different soil types: a sandy loam (well-drained) and a silty loam (moderately well-drained). The planting hole had the major effect at both sites; large holes (25 liters) shoveled with straight or angled sides resulted in more shoot and root dry weight and greater total root length than auger holes (21 liters) or small shovel holes (10 liters). Vine response to planting in a subsoil slot 0.5 m deep × 6 m long was similar to that in large holes in sandy soil and small holes in heavier soil. Root manipulation treatments had little effect on vine establishment. Root pruning at planting, with or without root separation, did not increase vine dry weight relative to an undisturbed root ball in either soil type, but total root length was increased by root pruning in the heavier silty loam soil. Peat amendment increased total root length in the sandy soil but not in the silty loam soil.
Pulsing with Triton X-100 Improves Hydration and Vase Life of Cut Sunflowers (Helianthus annuus L.)
Authors: Jones Rodney B. , Serek Margrethe , Reid Michael S.
Published: February 2019

The vase life of cut sunflowers given a simulated transport period (3 days dry storage at 8C) was significantly enhanced by a l-hour pulse with 0.01% Triton X-100 administered before storage. The Triton pulse increased solution uptake during the l-hour pulse, decreased fresh weight loss during dry storage, and significantly improved water uptake thereafter, resulting in greater leaf turgidity and longer vase life. Leaf stomata] conductance measurements indicated that Triton X-100 maintained stomatal opening at a higher level during the pulse and after storage, but had no effect during dry storage. Chemical name used: octylphenoxypolyethoxyethanol (Triton X-100).
Accuracy of Quantum Sensors Measuring Yield Photon Flux and Photosynthetic Photon Flux
Authors: Barnes Charles , Tibbitts Theodore , Sager John , Deitzer Gerald , Bubenheim David , Koerner Gus , Bugbee Bruce
Published: February 2019

Photosynthesis is fundamentally driven by photon flux rather than energy flux, but not all absorbed photons yield equal amounts of photosynthesis. Thus, two measures of photosynthetically active radiation have emerged: photosynthetic photon flux (PPF), which values all photons from 400 to 700 nm equally, and yield photon flux (YPF), which weights photons in the range from 360 to 760 nm according to plant photosynthetic response. We selected seven common radiation sources and measured YPF and PPF from each source with a spectroradiometer. We then compared these measurements with measurements from three quantum sensors designed to measure YPF, and from six quantum sensors designed to measure PPF. There were few differences among sensors within a group (usually <5%), but YPF values from sensors were consistently lower (3 % to 20 %) than YPF values calculated from spectroradiometric measurements. Quantum sensor measurements of PPF also were consistently lower than PPF values calculated from spectroradiometric measurements, but the differences were <7% for all sources, except red-light-emitting diodes. The sensors were most accurate for broad-band sources and least accurate for narrow-band sources. According to spectroradiometric measurement, YPF sensors were significantly less accurate (>9% difference) than PPF sensors under metal halide, high-pressure sodium, and low-pressure sodium lamps. Both sensor types were inaccurate (>18% error) under red-light-emitting diodes. Because both YPF and PPF sensors are imperfect integrators, and because spectroradiometers can measure photosynthetically active radiation much more accurately, researchers should consider developing calibration factors from spectroradiometric data for some specific radiation sources to improve the accuracy of integrating sensors.
High Carbohydrate Content in Snap Bean Leaves Stimulates Chinese Rose Beetle Feeding
Authors: Furutani Sheldon C. , Arita Lorna H. , Nagao Mike A.
Published: February 2019

Chinese rose beetle (CRB) (Adoretus sinicus Burmeister) preferential feeding based on leaf carbohydrate content was determined using `Hawaiian Wonder' snap bean (Phaseohs vulgaris L.) plants exposed to 0% ,40%, or 80% shade for 2 days. Plants exposed to 0% shade before CRBs fed had 8.5% leaf area consumed compared with 2.8% and 3.6% for 40% and 80% shade, respectively. Leaves exposed to 0% shade had a higher carbohydrate content than leaves exposed to 40% and 80% shade. Darkening the apical and subtending leaf with aluminum foil for 1 day before CRBs fed shifted CRB feeding from heavy feeding on the apical leaf and light feeding on the subtending leaves to a reversed feeding pattern-light feeding on the apical leaf and heavy feeding on the subtending leaves. Three snap bean cultivars grown under similar environmental conditions were compared to `Hawaiian Wonder' using a unifoliate split-leaf technique. Cultivars with a high endogenous carbohydrate content in their leaves had a higher percentage of leaf area consumed by CRBs than cultivars with low endogenous carbohydrates. This report suggests that high endogenous carbohydrate content in leaves stimulates CRB feeding.
Regulated Deficit Irrigation May Alter Apple Maturity, Quality, and Storage Life
Authors: Ebel Robert C. , Proebsting Edward L. , Patterson Max E
Published: February 2019

`Delicious' apple (Malus domestica Borkh.) trees received regulated deficit irrigation (RDI) early in the growing season to determine if fruit quality and storage life would he altered compared to well-watered trees. Soil moisture and leaf water potential were lower in RDI trees than in those that did not receive RDI most of the season. Internal ethylene concentration increased logarithmically earlier in RDI apples. At harvest, RDI fruit were smaller and had a higher soluble solids concentration (SSC) and lower titratable acidity. Starch degradation was delayed in RDI fruit, and their color was not affected. Firmness was not affected when the effect of size on firmness was removed. The SSC of RDI apples remained higher during storage, but starch content, titratable acidity, firmness, and color were similar.
Self- and Cross-compatibility among Apricot Cultivars
Authors: Burgos L. , Berenguer T. , Egea J.
Published: February 2019

Eight apricot (Prunus armeniaca L.) cultivars were self- and cross-pollinated to determine pollen compatibility. Pollen tube growth in the laboratory and the percentage of fruit set in the orchard were evaluated. The results confirmed that `Moniqui Fino' and `Velázquez Tardío' are self-incompatible and established that `Gitano', `Pepito del Cura', and `Velázquez Fino' are also self-incompatible. No cross-incompatibility was found in the 25 cross-combinations.
A Comparison of Staining Techniques for Somatic Chromosomes of Strawberry
Authors: Owen Henry R. , Miller A. Raymond
Published: February 2019

A factorial combination of pretreatments, fixatives, and stains was examined to identify the best available method for staining the chromosomes of strawberry (Fragaria × ananassa Duch. `Chandler') root-tip cells. Three pretreatments (a -bromonaphthalene, p -dichlorobenzene, and 8-hydroxyquinoline), three fixatives (Farmer's fluid, Carnoy's fluid, and Newcomer's fluid), and five stains (acetocarmine, alcoholic hydrochloric-acid carmine, altered carbol fuchsin, lacto-propionic orcein, and leucobasic fuchsin) were tested. Pretreatment with either a -bromonaphthalene (saturated aqueous) or 8-hydroxyquinoline (2 mm) for 5 hours at 14C, overnight fixation in Farmer's fluid, hydrolysis in 1 n HCl (15 minutes at 60C), and staining with altered carbol fuchsin produced chromosome preparations superior to other treatment combinations. Treatment with a-bromonaphthalene, Farmer's fluid, and alcoholic hydrochloric-acid carmine (2 days at 25C) also produced acceptable chromosome preparations.
Blueberry Shoestring Virus in Eastern North American Populations of Native Vaccinium
Authors: Hancock J.F. , Callow P.W. , Krebs S.L. , Ramsdell D.C. , Ballington J.R. , Lareau M.J. , Luby J.J. , Pavlis G.P. , Pritts M.P. , Smagula J.M. , Vorsa N.
Published: February 2019

Flower bud and leaf samples collected from a wide range of native North American Vaccinium populations were tested for the presence of blueberry shoestring virus (BBSSV) using the enzyme-linked immunosorbant assay. The highest disease incidence was found in Michigan (14%), although a few positive samples also were found in Virginia, New Jersey, Maine, Ontario, and Quebec. Of seven species tested, only V. corymbosum L. and V. angustifolium Ait. were infected with BBSSV.
Temperature and Seed Moisture Govern Storage Duration and Germination of Phlox drummondii
Authors: Carpenter W.J. , Ostmark E.R. , Cornell J.A.
Published: February 2019

Phlox drummondii Hook seed germinated well over a wide range of constant or alternating temperatures. Germination percentages at constant temperatures of 10 to 25C ranged from 94% to 98% for `Light Salmon' and from 83% to 88% for `Deep Salmon'. No seeds germinated at constant 30C. Total germination percentages at alternating temperatures ranged from 93% to 99% for `Light Salmon' and 67% to 82% for `Deep Salmon'. For both cultivars, the number of days to 50% of final germination (T50) and between 10% and 90% germination (T90-T10) decreased as constant temperatures or the median for alternating temperatures rose from 10 to 20C. The seeds had only limited desiccation tolerance. Reducing the moisture content of stored seed from 9 % to 5 % did not reduce total germination significantly, but 5% to 6% seed moisture levels increased the days to T50 and T90-T10 compared with higher moisture contents. The relative humidity and temperature that phlox seed received during long-term storage influenced germination. After seed was stored at 5C, germination generally was higher, earlier, and more uniform than after storage at 15 or 25C. The highest total germination percentages and shortest T50 and T90-T10 occurred following storage for 12 months at 5C and 20% to 40% relative humidity.
Heat Treatment Inhibits Mango Chilling Injury
Authors: McCollum T. Gregory , D'Aquino Salvatore , McDonald Roy E.
Published: February 2019

`Keitt' mango (Mangifera indica L.) were kept at 38C for 0, 24, or 48 hours before storage at 5C for 11 days. Nonheated fruit developed severe rind pitting and discoloration, whereas chilling injury symptoms decreased with increased duration at 38C. Respiratory rates were slightly higher in nonheated than in heated fruit. Nonheated fruit produced a transient burst of ethylene evolution following transfer to 21C; heated fruit did not produce a similar burst. Firmness was similar in nonheated and heated fruit at the time of transfer to 21C for ripening, but was slightly higher in nonheated fruit after 3 and 6 days of ripening. Soluble solids concentration was higher in heated than in nonheated fruit at the time of transfer to 21C, but was similar after 9 days at 21C. Commission Internationale de l'Eclairage a* and b* flesh values were higher in heated than in nonheated fruit. Results of this study indicate that mango tolerance to chilling temperatures may increase after prestorage heat treatment.
VARIABLE OXYGEN AND CARBON DIOXIDE CONCENTRATIONS DURING CONTROLLED ATMOSPHERE STORAGE OF `GOLDEN DELICIOUS' APPLES
Authors: Lehman-Salada Laura , Greene George M.
Published: February 2019

In both experiments. 20-apple samples from 6 commercial orchards were harvested and stored in 208 liter containers at 0C for 4, 6, and 8 months. Additional samples were removed from CA and held at 0C for 14 days before evaluation. Gas composition was measured and controlled 6 times per day using automatic control equipment.

In the first experiment, samples were stored at constant 0.0% CO2 and one of three O2 regimes (constant 2.0%. 0.5 rising to 3.5%. or 3.5% falling to 0.5% O2). Apples stored at 3.5% falling to 0.5% O2 during the storage period were softer than apples held at constant 2.0% or those held at 0.5% rising to 3.5% O2 during the storage period. Variable O2 concentrations did not influence weight loss during storage and insignificant scald, flesh browning, core browning, rot, and low 02 injury were observed.

In the second experiment, samples were stored at constant 2.0% O2 and one of three CO2 regimes (constant 0%, constant 5%. or 0% rising to 6% CO2). Constant 5% or rising CO2 conditions did not significantly influence flesh softening or weight loss during storage. Negligible CO2 injury was observed.
RELATIONSHIP BETWEEN CIELAB COORDINATES OF PEACH COLOR AND VISUAL RATINGS.
Authors: Boswell Walter , Bible Bernard , Singha Suman
Published: February 2019

Fruit of 34 peach (Prunus persica L. Batsch). cultivars were harvested at maturity and visually evaluated by panelists on a 1 to 10 scale, where 10 = excellent color. CIELAB coordinates (L* a* b*) of fruit color were measured at the midpoint between the stem and the calyx end with a Minolta CR-200b calorimeter on the blushed and ground areas of each fruit. Simple linear regressions of color coordinates with panel ratings indicated that blush chroma, blush L*, blush hue angle and E* (total color difference between ground and blush) all influence visual color evaluation. Not only does assessing fruit color with a calorimeter permit color to be reported in internationally accepted units, but the relationships indicate that instrumental values relate well to qualitative ratings.