bluuebunny/crossref_metadata_2025 huggingface dataset:
Sources of Resistance to Diaprepes Weevil in Subfamily Aurantiodeae, Rutaceae
Authors: Bowman Kim D. , Shapiro Jeffrey P. , Lapointe Stephen L.
Published: February 2019

Commercially used citrus rootstocks can all be seriously damaged by larvae of the sugar cane root weevil, Diaprepes abbreviatus (L.). Six greenhouse challenge experiments were used to compare the resistance of 24 selections of citrus rootstocks and related species to this weevil by measuring root damage, and larval growth and survival. The commercial rootstocks tested were found to be susceptible, while at least seven other species within the subfamily Aurantiodeae were observed to be significantly more resistant. The species Balsamocitrus dawei Stapf. was most resistant to weevil larvae, exhibited less root damage than commonly used rootstock cultivars, and significantly depressed larval growth and survival. The species Glycosmis pentaphylla (Retz.) Correa, Microcitrus australis (Planch.) Swing., Eremocitrus glauca (Lindl.) Swing., Severinia buxifolia (Poir.) Tenore, Triphasia trifolia (Burm. f.) P. Wils., and Citrus hystrix DC. suffered as much damage from the weevil as common rootstock cultivars but significantly depressed growth of larvae feeding on them. One new hybrid rootstock, HRS-801, also significantly depressed D. abbreviatus larval growth, but this effect has not yet been verified as having significance in a long-term or field situation. Several strategies are discussed for developing citrus rootstocks resistant to D. abbreviatus.
Annual Bluegrass and Creeping Bentgrass Response to Varying Levels of Iron
Authors: Xu Xia , Mancino Charles F.
Published: February 2019

Many biotypes of annual bluegrass (Poa annua L.) are found on golf course putting greens. Although normally considered an invasive weed, annual bluegrass can provide as good a putting surface as creeping bentgrass (Agrostis palustris Huds.). The most desirable biotypes of annual bluegrass are primarily vegetative and have a low flowering frequency. Whether the nutritional requirements of annual bluegrass biotypes differ from one another or from creeping bentgrass is unknown. The response of three flowering (FAB, high seedhead production) and three vegetative (VAB, low seedhead production) biotypes of annual bluegrass (AB), and the three parents of `Penncross' creeping bentgrass (CB) to varying levels of iron (Fe) in greenhouse sand culture was investigated. After establishment, clones were grown for 3 weeks and irrigated with a half-strength Hoagland's solution containing 0, 2, 4, 6, and 8 mg·L-1 Fe in citrate-Fe. Shoot and root responses to Fe were similar for the VAB and FAB biotypes. However, VAB had higher color ratings (darker green leaf color) with Fe treatment level at 4 mg·L-1 than did FAB or CB, which required 6 mg·L-1 Fe for acceptable color. Growth of creeping bentgrass was greater than that of annual bluegrass at every Fe level tested. Shoot dry weights of CB increased significantly with Fe treatment level up to 6 mg·L-1. Shoot dry weight of AB increased up to 4 mg·L-1 Fe and then declined at ≥6 mg·L-1. Root growth of CB increased up to 6 mg·L-1 Fe, but then decreased significantly at 8 mg·L-1 Fe. Root growth of AB increased slightly up to 4 mg·L-1 Fe and then declined at 6 and 8 mg·L-1. Shoot tissue concentrations of Fe were similar for AB and CB at each Fe rate tested except at 8 mg·L-1 Fe, where Fe levels in CB were significantly lower. Based on this work, creeping bentgrass and annual bluegrass respond differently to Fe nutrition, but different biotypes of annual bluegrass appear to respond similarly.
Gibberellic Acid Applied at Bloom Reduces Fruit Set and Improves Size of 'Crimson Seedless' Table Grapes
Authors: Dokoozlian N.K. , Peacock W.L.
Published: February 2019

Excessive fruit set can reduce the quality of 'Crimson Seedless' table grapes (Vitis vinifera L.), resulting in compact, tightly filled clusters with small berries that are prone to bunch rot at harvest. Two separate studies were conducted to examine the effects of application timing and rate on the efficacy of GA3 for berry thinning. In the first experiment, vines were treated with 2 g·ha-1 GA3 at one of the following stages of bloom: 1% to 5%; 20% to 30%; 50% to 60%; 80% to 90%; or 100% capfall (falling of the calyptra). The second experiment compared treatments of 0, 2.5, 6.25, 12.5, 18.75, or 25 g·ha-1 GA3 applied at ≈80% bloom. Fruit set (number of berries/cm shoulder length) was similar among vines treated between 1% to 5% and 100% bloom with 2 g·ha-1 GA3, although berry set was reduced relative to the control. However, applications made during the later stages of bloom significantly increased berry length and weight. Fruit set generally declined, and the number of shot berries per cluster increased, as the amount of GA3 applied at bloom increased. Applications ≥6.25 g·ha-1 GA3 resulted in commercially unacceptable levels of shot berries, as well as significant reductions in cluster weight and packable yield per vine. The results indicate that a single application of 2.5 g·ha-1 GA3 near full bloom may be used to reduce fruit set and increase berry size of this cultivar without detrimental effects on packable yield or cluster number per vine the subsequent year. Chemical name used: gibberellic acid (GA3).
A Ratoon Cropping System for Fall Bell Pepper Production
Authors: Kahn Brian A. , Leskovar Daniel I.
Published: February 2019

Studies were conducted to examine the effects of pruning treatments applied to spring-transplanted bell peppers (Capsicum annuum L.) on marketable fruit yield in late summer and fall. Control plants were set in the field in early May 1997 (Oklahoma) and Apr. 1998 (Oklahoma and Texas) and harvested weekly into October (Oklahoma) or periodically into December (Texas). In 1997, all four treatments (involving height and method of pruning) reduced total marketable fruit weight, but differences among treatments were nonsignificant. In Oklahoma in 1998, plants were mowed on 27 July at an average height of ≈24 cm. Mowed plants produced less total marketable fruit weight but more U.S. Fancy fruit than did control plants, while weight of U.S. No. 1 fruit was not affected. In Texas in 1998, plants mowed on 4 Sept. at a height of ≈20 cm produced more than twice the weight of U.S. No. 1 fruit and fewer cull fruit than did control plants. Nonpruned transplants set in the field in Summer 1998 (both Oklahoma and Texas) produced low marketable yields. Maintaining spring-transplanted bell peppers is a viable technique for fall pepper production, and the highest total marketable yields may be obtained if these plants are not mowed. However, mowing offers an opportunity for increased fall production of premium fruit, and mowed plants would be easier to manage than nonpruned plants.
Oxadiazon, Oryzalin, and Oxyfluorfen Residues in Container Plant Nurseries
Authors: Goodwin P.B. , Beach S.
Published: February 2019

Ronstar® and Rout® are two of the most common and effective preemergent herbicides used by the nursery industry. However, there is some uncertainty as to what happens to the chemicals in nurseries that are recycling their runoff water. The fate of the chemicals has been studied in two nurseries that are completely dependent on recycled water. Negligible amounts were found in the recycled irrigation water. Most of each herbicide remained where it was applied, either close to the top in the substrate, or on the surface of the growing area, for periods of ≈4 months. Five months after application, <10% of oryzalin remained vs. ≈30% of the oxyfluorfen and oxadiazon. Less residue was produced if oxadiazon was applied when the pots were packed together after potting up, compared to application to spaced pots in the standing area. These herbicides are of low mammalian toxicity, and the main hazard is from contamination on the standing area after application, and from the top layer of substrate. To minimize any risk, we recommend that the herbicides be applied before the plants are spaced out on the growing area, and that staff handling the pots take suitable precautions, and in particular avoid inserting their unprotected hands into the top of the mix. Chemical names used: 2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin-5-one (oxadiazon); 4-(dipropylamino)-3,5,-dinitrobenzenesulfonamide (oryzalin); 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trichloromethyl)benzene (oxyfluorfen); tritium-labelled [N-(4-chloro-2-fluoro-S-(propargyloxy)-phenyl]-3,4,5,6-tetrahydrophthalimide [3H]THP.
Development of the Press Extraction Method for Plug Substrate Analysis: Quantitative Relationships Between Solution Extraction Techniques
Authors: Scoggins Holly L. , Bailey Douglas A. , Nelson Paul V.
Published: February 2019

Substrate electrical conductivity (EC), pH, and nutrient content should be monitored frequently during seedling plug production. Current testing methods are either complicated, unsuited to plug production, or interpretation standards do not exist. This study compares the press extraction (PE) method developed at North Carolina State Univ. with the saturated media extract (SME) method and the 1 substrate: 2 water suspension method (1:2). These solution extraction methods were applied to plug trays containing peat-based germination mix treated with four levels of fertilizer. Two sample sizes of 20 or 60 plug cells were used to determine if the smaller, less destructive sample size would produce satisfactory results. Resulting pH values varied within 0.3 units among methods, but variability in EC and nutrient content was greater. The PE method resulted in the highest values for EC, NH4+-N, NO3--N, K, Ca, and Mg while sample size had little effect on analyses. The three extraction methods were then compared on peat- and coir-based substrates. Within substrates, pH, EC, and nutrients tested were similar for the PE and the SME. The coir extract had a higher pH and much higher levels of K and Na than did the peat extract but was lower in N, P, Ca, and Mg. Overall, fairly strong correlations among testing methods were found, especially between the SME and PE.
Sweetpotato Periderm Components Inhibit In Vitro Growth of Root Rotting Fungi
Authors: Harrison Howard F. , Peterson Joseph K. , Clark Christopher A. , Snook Maurice E.
Published: February 2019

Sweetpotato [Ipomoea batatas (L.) Lam.] periderm components were tested for their effect on four fungi that infect sweetpotato roots: Fusarium oxysporum Schlecht. f. sp. batatas (Wollenw.) Snyd. & Hans. and F. solani (Sacc.) Mart., both of which cause stem and root disease; and Lasiodiplodea theobromae (Pat.) Griffon & Maubl. and Rhizopus stolonifer (Ehr. ex Fr.) Lind., both of which cause storage root disease. Sequential extracts of `Regal' sweetpotato periderm with hexane, methanol, and 50% methanol were inhibitory to the four fungi when incorporated into potato dextrose agar medium in petri dish bioassays. The methanol and 50% methanol extracts were much more active than the hexane extract and were combined for further study. Sephadex LH-20 column chromatography of the combined extracts, followed by bioassay with F. oxysporum indicated that the most inhibitory fraction contained the least polar components of the extract. Resin glycosides isolated from `Regal' periderm inhibited F. oxysporum, but the glycosides exhibited little concentration effect and were not as active on a tissue weight basis as other components. Periderm extracts from 10 sweetpotato clones exhibited large differences in inhibitory activity in bioassays with the four fungi. The sensitivity of the fungi to inhibition by the periderm extracts suggests that periderm components may provide protection against soil pathogens, but a relationship between such components and disease resistance was not established.
Combined In Vitro and In Vivo Propagation for Rapid Multiplication of Grapevine cv. Arka Neelamani
Authors: Thomas Pious , Schiefelbein John W.
Published: February 2019

A novel combination of in vitro and in vivo approaches was employed to generate sufficient stock of an introduced grape (Vitis vinifera L.) cv. Arka Neelamani which significantly accelerated the multiplication rate. The in vitro part included induction of root and shoot growth in shoot tip and nodal microcuttings in MS medium containing 1 μm IAA, sequential pruning of shoots at 1, 1.5, and 2 months, leaving the basal one to two nodes, resulting in fresh sprouts on the stump, and use of remaining stumps for in vivo establishment. The in vivo part included acclimatization of in vitro rooted plantlets and stumps, use of single node cuttings from 1.5- to 2-month-old in vivo shoots for the subsequent propagation, and utilizing the fresh sprout growth from these cuttings and in vivo stumps for further propagation. Employing both in vitro and in vivo approaches, we achieved a multiplication rate unparalleled to the general micropropagation or conventional propagation and significant stock was obtained within 6 months of introducing the material. The in vivo plants exhibited adult characters like distichous phyllotaxy, three lobed leaves and normal pattern of tendril development within 2 months from planting.
Consumer Product and Service Preferences Related to Landscape Retailing
Authors: Brand Mark H. , Leonard Robert L.
Published: February 2019

Survey data from 788 single-family residences from New England were analyzed to evaluate purchasing preferences and gardening habits. Particular attention was focused on plant attributes and choices of independent garden centers vs. mass merchandisers. Independent garden centers, magazines, and friends were the most important sources of gardening information, while mass merchandisers were relatively unimportant information sources. While consumers trusted information received at independent garden centers, they did not trust mass merchandiser information as much. The most important product and service attributes of retail establishments were well-maintained plants, informative signage, knowledgeable staff, and a wide selection of plant material. Gardening chemicals and fertilizers were purchased at mass merchandisers due to price. Consumers preferred to purchase high-value, long-lived plants (trees and shrubs) at independent garden centers due to higher plant quality and access to knowledgeable staff. When making plant purchases, plant appearance was the most important consideration regardless of whether the plant was an annual, perennial, or woody plant. The presence of flowers on plants was not ranked as influential in making purchase selections, but evidence of new growth, the presence of dark green foliage, and knowledge of a northern-grown source were important. For trees and shrubs, the significance of a plant guarantee and knowledge of a northern-grown source increased in importance in comparison to annuals and perennials.
Nitrous Oxide Inhibits In Vitro Growth of Multiple Postharvest Fungi
Authors: Qadir Altaf , Hashinaga Fumio
Published: February 2019

Nitrous oxide (N2O) was tested as a potential fungicidal or fungistatic compound. Twelve postharvest fungi were exposed to 10 to 80 kPa with 20 kPa O2 in a static system at 20 °C. These fungi were divided into N2O high-, medium- and low-sensitive groups. Based on growth sensitivity, growth of high-sensitive fungi was completely inhibited, and that of medium-sensitive fungi up to 85%. With low-sensitive fungi, significant inhibition was achieved only when the fungi were exposed to N2O continuously for 6 days. Botrytis cinerea Pers.: Fr., Colletotrichum acutatum Simmonds, Monilinia fructicola (Winter) Honey, Penicillium expansum Link, Penicillium italicum Wehmer, Phytophthora citrophthora (R.E. Smith and E.H. Smith) Leonian and Rhizopus stolonifer (Ehrens.: Fr.) Vuillemin, were high-sensitive; Glomerella cingulata (Stoneman) Spaulding was medium-sensitive, and Alternaria alternata (Fr.) Keissler, Fusarium oxysporum Schlechtend1: Fr. f. sp. fragariae Winks and Williams, Fusarium oxysporum Schlechtend1: Fr. f. sp. lycopersici (Saccardo) Snyder and Hansen., and Geotrichum candidum Link., were low-sensitive fungi. Addition of up to 100 μL·L-l C2H4 did not reduce inhibition caused by N2O. The inhibitory effect of N2O was considered to be due to biophysical properties similar to CO2, the competitive inhibition on C2H4 action, or the biosynthesis of methionine. These results indicate the potential of N2O to control some postharvest decay fungi.
Crop Load Reduction and Fruit Size Following Multi-step Thinning of 'Empire' Apple
Authors: Stover Ed , Fargione Mike , Risio Richard , Yang Xiaoe
Published: February 2019

Two years of field experiments were conducted in eastern New York to evaluate the efficacy of a multi-step thinning approach on reducing crop load (no. fruit per cm2 trunk cross-sectional area) and increasing fruit size of 'Empire' apple (Malus ×domestica Borkh.). Applications of Endothall (ET) at 80% bloom, NAA + carbaryl (CB) at petal fall (PF), and Accel™ + CB at 10 mm king fruitlet diameter (KFD), alone and in all combinations, were compared to a nonthinned control and to the application of NAA + CB at 10 mm KFD (commercial standard). In both 1996 and 1997, orthogonal contrasts indicated the multi-step treatment significantly increased fruit size, reduced cropload, and reduced yield compared to single applications. Effects on cropload of consecutive treatments were largely predicted by multiplying effects of individual treatments. Although all thinning treatments except for NAA + CB at PF in 1997 significantly reduced cropload, no single treatment thinned sufficiently to ensure good return bloom. Compared to NAA + CB at 10 mm KFD, multi-step thinning with NAA + CB at PF followed by Accel™ + CB at 10 mm KFD produced bigger fruits in both years, and resulted in a higher percentage of spurs carrying a single fruit in 1996. When fruit size was evaluated after removing the effect of cropload (cropload adjusted fruit weight), NAA + CB at PF, Accel™ + CB at 10 mm, and the two applied sequentially, resulted in greater cropload adjusted fruit weight than the nonthinned control in both years, whereas NAA + CB at 10 mm did not. Contrast analysis of treatments with and without ET showed no significant effect of including ET on fruit size, though total cropload was reduced at P = 0.10 and total yield was reduced (P = 0.03 in 1996 and P = 0.12 in 1997). No deleterious effects from multi-step treatments have been observed. All thinning treatments significantly increased return bloom in 1996 and 1997 compared to the control with little difference observed between treatments. Chemical names used: naphthalene acetic acid (NAA); 1-naphthyl-N-methylcarbamate [carbaryl (CB)]; 6-benzyladenine [BA (Accel™)]; 7-oxabicyclo (2,2,1) heptane-2,3 dicarboxylic acid [ET (Endothall™)]
Thymol and Acetic Acid Vapors Reduce Postharvest Brown Rot of Apricots and Plums
Authors: Liu W.T. , Chu C.L. , Zhou T.
Published: February 2019

Fumigation with 1 mg·L-1 of thymol vapor retarded mycelial growth of Monilinia fructicola (G. Wint.) Honey. Mean colony diameter was reduced from 49 mm in the control to 13 mm when the conidia were cultured on potato dextrose agar. Fumigation of apricots (Prunus armeniaca L.) with 2 mg·L-1 of thymol vapor reduced the germination of M. fructicola conidia to 2% compared with 98% on untreated fruit. Microscopic observations showed that the spores fumigated with thymol were shrunken and had collapsed protoplasts. In in vivo experiments, surface-sterilized apricots and plums (Prunus salicina L.) were inoculated with conidia of M. fructicola by applying 20 μL of a spore suspension to wounds on the fruit, and then were fumigated with thymol or acetic acid. The incidence of brown rot was reduced to 3% and 32% when `Manch' apricots were fumigated with thymol or acetic acid at 5 mg·L-1, respectively, compared with 64% incidence in untreated fruit. Fumigation of `Violette' plums with thymol or acetic acid at 8 mg·L-1 reduced brown rot from 88% in the control to 24% and 25%, respectively. Fumigation of `Veeblue' plums with thymol at 4 mg·L-1 reduced brown rot from 56% in the control to 14%. Fumigation of apricots with thymol resulted in firmer fruit and higher surface browning, but total soluble solids and titratable acidity were not affected. Fumigation of plum with thymol resulted in higher total soluble solids, but firmness and titratable acidity were not affected. Thymol fumigation caused phytotoxicity on apricots but not on plums.
Multi-color Genomic In Situ Hybridization Identifies Parental Chromosomes in Somatic Hybrids of Diospyros kaki and D. glandulosa
Authors: Choi Young-A , Tao R. , Yonemori K. , Sugiura A.
Published: February 2019

Multi-color genomic in situ hybridization (MCGISH) was performed for mitotic cells of the somatic hybrids of Diospyros kaki (2n = 6x = 90) and D. glandulosa (2n = 2x = 30). Total DNA of D. kaki and D. glandulosa were isolated and labeled with biotin-16-UTP and digoxigenin (DIG)-11-UTP, respectively. The labeled DNAs were used as probes to differentiate parental chromosomes. The biotin-labeled probe was detected with avidin-rhodamine, and the DIG-labeled probe was detected with anti-DIG-FITC (fluorescein isothiocyanate). Ninety chromosomes from D. kaki that showed reddish-orange and 30 chromosomes from D. glandulosa that showed greenish-yellow were observed under a fluorescence microscope. Some chromosomes showed cross-hybridization with both probes at their terminal or other chromosome regions. These results indicated that MCGISH could be used to analyze genomes of Diospyros species whose chromosomes are small and numerous.
Microsatellite Markers Differentiate Eight Giessen Cherry Rootstocks
Authors: Struss D. , Boritzki M. , Karle R. , Iezzoni A.F.
Published: February 2019

Two rootstocks from the Giessen (GiSelA) series of dwarfing cherry (Prunus sp.) rootstocks, GiSelA (GI) 5 (syn. 148/2) and GI 6 (syn. 148/1), are becoming commercially important and five other Giessen cherry rootstocks are being evaluated for horticultural traits. Since GI 5 and GI 6 are morphologically similar, a DNA fingerprinting project was undertaken to identify molecular markers that could be used by the nursery industry to differentiate these two rootstocks. The project was extended to include six additional Giessen rootstocks of varying pedigrees. Fourteen DNA primer pairs were tested for their ability to differentiate among the eight rootstocks. None of the primer pairs could differentiate all eight rootstock selections; however, three primer pairs could differentiate all but two selections. Two primer pairs, PMS 15 and PceGA59, were identified as the most suitable for high throughput screening of GI 5 and GI 6 due to the simplicity and the size of the base pair differences among the polymorphic fragments. These results demonstrate the utility of molecular markers to differentiate the Giessen cherry rootstocks.
Effect of Soil Temperature on K and Ca Concentrations and on ATPase and Pyruvate Kinase Activity in Potato Roots
Authors: Ruiz Juan M. , Hernández Joaquín , Castilla Nicolas , Romero Luis
Published: February 2019

Potato (Solanum tuberosum L.) `Spunta' plants were grown with the root zone covered by different types of polyethylene plastic mulches. The plastic mulches used were transparent, white, co-extruded black and white, and black. As a control, plants were grown without plastic mulch. The parameters analyzed were soil temperature, root concentration of K and Ca, and enzymatic activities of ATPase and pyruvate kinase (PK), measured as basal and in the presence of K+ and Ca2+. The physical characteristics of the plastic mulches directly influenced soil and root temperatures in potato plants. In addition, the concentration of cations in the roots (particularly Ca2+) and basal ATPase activity were affected by soil temperature, whereas basal PK was not affected by soil temperature. The use of co-extruded black and white plastic mulch improved the nutritional status of Ca in the roots of potato plants. Finally, the basal ATPase and PK activities in the presence of K+ and Ca2+ were related with the root levels of these cations.
Nitrogen Use Efficiency and Onion Yield Increased with a Polymer-coated Nitrogen Source
Authors: Drost Dan , Koenig Rich , Tindall Terry
Published: February 2019

Nitrogen (N) losses can be substantial in furrow-irrigated onions (Allium cepa L.). Polymer-coated urea (PU) may reduce N losses and result in an increase in productivity. In this study, we investigated the effects of different rates and blends of urea and PU on onion yield and N use for two cropping seasons. Nitrogen was applied at 112, 168, and 224 kg·ha-1 as PU or urea. In addition, three PU/urea blends equal to 224 kg·ha-1 of N were compared. Plant growth and N concentration, soil nitrate concentrations, and bulb yield were evaluated each year. Onion yield decreased by 95 Mg·ha-1 for each 25% increase in the proportion of urea in the fertilizer blends. Reducing the N rates from 224 to 112 kg·ha-1 had minimal effect on bulb yield when all the fertilizer was supplied by urea. A reduction of N applied from 224 to 168 kg·ha-1 had little effect on yield, although a further reduction to 112 kg·ha-1 did significantly reduce bulb yield when the entire N was supplied from PU. Nitrogen source and rate had no effect on bulb maturity and only minor effects on leaf area and storage potential. Soil sampling indicated that more N was retained in PU-treated onion beds than in urea-treated beds, which improved nitrogen use efficiency. In addition, N use efficiency improved when there was more PU in the blend and when PU was compared with urea at the same rate. We conclude that the use of PU can dramatically improve N use efficiency and productivity in direct-seeded onions.
One-time vs. Continuous Application of Paclobutrazol in Subirrigation Water for the Production of Bedding Plants
Authors: Million J.B. , Barrett J.E. , Nell T.A. , Clark D.G.
Published: February 2019

Experiments were conducted with four kinds of flowering plants to compare one-time vs. continuous application of paclobutrazol in subirrigation water. When a crop reached the stage at which it required growth regulator treatment, four concentrations of paclobutrazol were applied via subirrigation either one-time or continuously until the crop was terminated. Based upon regression equations, concentrations resulting in 30% size reduction for one-time applications of paclobutrazol were 0.01 mg·L-1 for Begonia ×semperflorens-cultorum `Cocktail Gin', 0.09 mg·L-1 for Impatiens wallerana Hook. `Super Elfin White', 0.2 mg·L-1 for Dendranthema ×grandiflorum (Ramat.) Kitamura `Tara', and 2.4 mg·L-1 for Petunia ×hybrida Vilm.-Andr. `Plum Crazy'. Respective optimal values for continuous application were 0.005, 0.02, 0.06, and 0.4 mg·L-1. Increasing the concentration for continuous application had a greater effect on paclobutrazol efficacy than did increasing the concentration for a single application. In a trial with impatiens `Super Elfin Salmon Blush', the paclobutrazol concentration was reduced 0%, 25%, 50%, 75%, or 100% (single application) for each successive subirrigation event following an initial application of 0.1 mg·L-1 of paclobutrazol. The 50%, 75%, and 100% reduction treatments provided similar levels of size control. Dilution was more important when the reduction rate was less than 50%. Chemical name used: (±)-(R*,R*)-β-[(4-chlorophenyl)methyl]-α-(1,1-dimethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).
Gibberellic Acid Application Timing Affects Fruit Quality of Processing Oranges
Authors: Fidelibus Matthew W. , Davies Frederick S. , Campbell Craig A.
Published: February 2019

Gibberellic acid (GA3) increases juice yield of processing oranges, but results are inconsistent. Preliminary research suggested that this variability might be related to application timing. Therefore, we conducted an experiment to determine the optimal time to apply GA3 for increasing juice yield of `Hamlin', `Pineapple', and `Valencia' sweet oranges [Citrus sinensis (L.) Osb.]. Mature trees of each cultivar were sprayed with ≈10 L of a solution of GA3 (45 g·ha-1 a.i.) and organo-silicone surfactant (Silwet, 0.05%) between 2 Sept. and 9 Dec. 1998, and 25 Sept. and 9 Dec. 1999, or remained non-sprayed (control). Generally, the earliest application dates were most effective at maintaining peel puncture resistance above that of control fruit, while the latest application dates resulted in the most green peel color at harvest. Juice yield of `Hamlin' and `Valencia', but not `Pineapple', was increased by GA3 at some application timings and harvest dates in both years. The increase in juice yield was related to time between application and harvest; juice yield of `Hamlin' was greatest ≈2 months, and `Valencia' ≈5 months after GA3 application. Treated fruit often had lower juice Brix than non-sprayed fruit, a phenomenon that often paralleled treatment effects on peel color. When treatments did not increase juice yield but reduced juice Brix, then yield of solids was sometimes lower than for non-treated fruit. Treatments generally delayed flowering of `Pineapple' and `Valencia' but not `Hamlin'.
Internal Bruising Alters Aroma Volatile Profiles in Tomato Fruit Tissues
Authors: Moretti Celso L. , Baldwin Elizabeth A. , Sargent Steven A. , Huber Donald J.
Published: February 2019

Tomato (Lycopersicon esculentum Mill.) fruit, cv. Solar Set, were harvested at the mature-green stage and treated with 50 μL·L-1 ethylene at 20 °C. Individual fruits at the breaker stage (<10% red color) were dropped onto a solid surface to induce internal bruising. Dropped and undropped fruit were stored at 20 °C until red-ripe, at which time pericarp, placental, and locule tissues were excised. Tissues from dropped tomatoes were examined for evidence of internal bruising and all tissues were analyzed for selected volatile profiles via headspace analysis. Individual volatile profiles of the three tissues in bruised fruit were significantly different from those of corresponding tissues in undropped, control fruit, notably: trans-2-hexenal from pericarp tissue; 1-penten-3-one, cis-3-hexenal, 6-methyl-5-hepten-2-one, cis-3-hexenol and 2-isobutylthiazole from locule tissue; and 1-penten-3-one and β-ionone from placental tissue. Alteration of volatile profiles was most pronounced in the locule tissue, which was more sensitive to internal bruising than the other tissues. Changes observed in the volatile profiles appear to be related to disruption of cellular structures.
Arthropod Resistance in a Petunia Ecotype with Glabrous Leaves
Authors: Griesbach R.J. , Neal J.W. , Bentz J.
Published: February 2019

A novel ecotype of Petunia integrifolia subsp. integrifolia var. depauperata with glabrous leaves was found near the town of Torres, Brazil, and hybridized with P. ×hybrida. In the F1 and F2 generations, the glabrous leaf trait was quantitatively inherited with high heritability. The absence of trichomes was not associated with the decrease in the resistance of the glabrous-leaved species and hybrids to aphids, but was correlated with a lower resistance to spider mites.
Interspecific Hybridization in Clethra
Authors: Reed Sandra M. , Joung Younghee , Roh Mark
Published: February 2019

The genus Clethra contains many ornamental species, of which the most adaptable and cold hardy is C. alnifolia L. The objective of this study was to obtain hybrids between C. alnifolia and three other ornamental Clethra species, C. acuminata Michx., C. fargesii Franch., and C. pringlei S. Wats. Viable plants were obtained from reciprocal crosses between C. alnifolia and C. fargesii, and from crosses between C. alnifolia and the other two species when C. alnifolia was used as the maternal parent. Randomly amplified polymorphic DNA (RAPD) markers were used to verify hybridity and to compare hybrids to their parents. In all cases, the hybrids had more RAPD markers in common with C. alnifolia than with their other parent. Close clustering by neighbor-joining analysis of RAPD markers and the morphological resemblance of C. alnifolia × C. acuminata and C. fargesii × C. alnifolia plants to their paternal parent indicated that these plants were of hybrid origin. The C. alnifolia × C. pringlei plants resembled C. alnifolia in many respects, but they stayed green much later in the year than did C. alnifolia with leaves remaining on the plants throughout the winter. These foliage characteristics were presumed to reflect the contribution of the evergreen C. pringlei, and thus were regarded as evidence of hybridity.
Damage by Early Autumn Freeze Varies with Pecan Cultivar
Authors: Smith Michael W.
Published: February 2019

Pecan [Carya illinoinensis (Wangenh.) C. Koch.] trees were injured by freezing temperatures in Oct. 2000, occurring about 4 weeks before the average first freeze and 6 weeks before the normal killing freeze (less than or equal to -2 °C). Nonbearing and bearing cultivars were rated for injury at four sites the following May. Nonbearing cultivars with little or no damage included `Caddo', `Clark II', `Giles', `Kanza', and `Peruque'. Those that had substantial damage included `Maramec', `Pawnee', `Oconee', `Shawnee', and `OK642'. Bearing cultivars with little or no injury included `Stuart', `GraKing', `Pawnee', `Tejas', and `Wichita'. The most severely damaged bearing cultivars were `Gratex', `Shoshoni', and `Squirrel's Delight'.
Short-term Cyclic Cold Temperature Stress on Watermelon Yield
Authors: Korkmaz Ahmet , Dufault Robert J.
Published: February 2019

Watermelon [Citrullus lanatus (Thunb) Matsum. & Nakai.] seedlings may be repeatedly exposed to temperatures alternating between almost freezing and optimum soon after field transplanting. `Carnival', `Crimson Sweet', `Millionaire' and `Crimson Trio' watermelon transplants were exposed to cold temperature stress at 2 ± 1 °C in a walk-in cooler and then to 29 ± 5 °C in a greenhouse immediately before field planting to simulate temperature alternations that may occur after field transplanting. Cold-stressed transplants were field planted after all risk of ambient cold stress passed. In 1998, transplants were exposed to 2 °C from 9 hours to 54 hours, and in 1999 from 9 to 81 hours. Early yields of all cultivars, except Carnival, significantly decreased with increasing hours of cold stress in both years. Total yields of `Carnival' decreased linearly in both years with a 10% yield reduction occurring from 14 to 15 hours of cold stress. `Crimson Sweet' yields were reduced in 1999 only, with 16 hours of cold stress reducing yield 10%.
Using Cowpea to Manage Soil Phosphorus Accumulation from Poultry Litter Applications in a Cool-season Vegetable Rotation
Authors: Alsup Clydette M. , Kahn Brian A. , Payton Mark E.
Published: February 2019

Cowpea [Vigna unguiculata (L.) Walp.] cover crops were grown in a rotation with broccoli (Brassica oleracea L. var. italica Plenck.), spinach (Spinacia oleracea L.), and turnip greens [Brassica rapa L. var. (DC.) Metzg. utilis] to evaluate the legume's ability to remove excess P from soils when poultry litter was used as a fertilizer. Fertilizer treatments were: 1) litter to meet each crop's recommended preplant N requirements (1×); 2) litter at twice the recommended rate (2×); and 3) urea at the 1× rate as the control. Following the vegetable crops, cowpeas were planted on half of each replication, while the other half was fallowed. The cowpeas were harvested at the green-shell seed stage and then underwent a simulated haying operation to remove remaining shoot material from the field. Soil samples were taken at 0-15 cm and 15-30 cm depths at the onset of the study and after each crop to monitor plant nutrient concentrations. The cowpeas lowered soil test N concentrations at both soil sampling depths, but had no consistent effect on soil test P concentrations. Soil test P at the 0-15 cm depth was not increased by litter at the 1× rate but was increased by litter at the 2× rate relative to the urea control, regardless of cropping system. Poultry litter was effective as a fertilizer for all three vegetable crops, but the 1× rate appeared inadequate for maximum production of broccoli and turnip greens.
Recycled Newspaper Reduces Nutrient Leaching from Container-grown Poinsettia
Authors: Glenn J.S. , Gilliam C.H. , Edwards J.H. , Keever G.J. , Knight P.R. , Olive J.W.
Published: February 2019

Two experiments were conducted to evaluate recycled newspaper products as nutrient filters in the bottom of containers. In Expt. 1 with poinsettia, Euphorbia pulcherrima Willd. ex Klotzsch `Glory', three paper products were evaluated: ground paper, paper crumble, and paper pellets; each placed 2 or 3 cm deep in the bottom of containers, so that drainage holes were covered. Leachate samples were collected at the first irrigation after each liquid fertilization. Nitrate (NO3--N) and ammonium (NH4+-N) leachate concentrations were reduced up to 84% with recycled paper pellets, compared to the control (no paper). Recycled paper retained up to 732 mg of nitrogen (N) per container (paper pellets 3 cm deep). Shoot dry weight was reduced with paper pellets but was not affected by ground paper or paper crumble. In Expt. 2, `Freedom Red' poinsettias were grown with either single weekly applications of 500 mg·L-1 N from Peter's 20N-4.3P-16.6K, or 200 mg·L-1 N at each irrigation (2 or 3 times a week, as needed). Recycled paper treatments included paper crumble or paper pellets placed 2.5 cm deep in the bottom of containers, and a control without paper. Leachate NO3--N and NH4+-N concentrations were reduced up to 100% and 94%, respectively, 6 days after planting (DAP), and up to 57% and 50%, respectively, 25 DAP with paper crumble compared to nonpaper control. Paper pellets in the bottom of containers retained up to 776 mg N per container. Poinsettia shoot dry weight was lowest with paper pellets in the bottom of containers and continuous fertilization.
High-pressure Sodium Lighting Affects Greenhouse Production of Vegetative Cuttings for Specialty Annuals
Authors: Donnelly Caroline S. , Fisher Paul R.
Published: February 2019

The objective was to quantify the effect of supplemental lighting on cutting production for 10 herbaceous annual cultivars. Stock plants of four cultivars (Heliotropium arborescens `Atlantis', Petunia `Supertunia Sun Snow', Scaevola aemula `New Wonder', and Verbena `Tapien Soft Pink') received ambient light [average 6.2 mol·m-2·d-1 photosynthetic photon flux (PPF) during the photoperiod], or ambient light plus either 1.6 or 2.8 mol·m-2·d-1 PPF from high-pressure sodium (HPS) lamps for 11 hours. In a second experiment, the same four species plus six other cultivars were grown under ambient light (average 7.9 mol·m-2·d-1 PPF) or ambient plus 1.9 mol·m-2·d-1 PPF from HPS. The effect of HPS on the production of cuttings varied greatly between species. Growth of Heliotropium was not significantly affected by light level in either experiment. In the first experiment, the addition of 1.6 mol·m-2·d-1 PPF from HPS increased the number of Petunia `Supertunia Sun Snow', Scaevola, and Verbena cuttings by 14%, 51%, and 12%. The addition of 2.8 mol·m-2·d-1 PPF from HPS, increased cuttings harvested from these three species by 23%, 73%, and 22% respectively. In the second experiment, Petunia `Supertunia Sun Snow', Scaevola, Aloysia triphylla (lemon verbena), and Osteospermum `Lemon Symphony' had a positive cutting production response to HPS (17% to 45% increase), whereas cutting numbers of other species (Argyranthemum `Summer Melody', Lantana `Patriot Firewagon', Impatiens New Guinea hybrid `Pedro', Petunia `Supertunia Blue Wren', and Verbena) were not significantly affected by HPS. In both experiments, cutting quality (length, stem caliper, fresh mass, and dry mass) and subsequent rooting of cuttings were not significantly affected by light level.
Development of a Superior Somaclone of Rose-scented Geranium and a Protocol for Inducing Variants
Authors: Gupta Ritika , Banerjee S. , Mallavarapu G.R. , Sharma S. , Khanuja S.P.S. , Shasany A.K. , Kumar Sushil
Published: February 2019

An efficient protocol has been established for generating somaclones in the Indian rose-scented geranium Pelargonium graveolens cv. Bipuli, which yields Reunion Island-type essential oil. Murashige and Skoog's (MS) medium supplemented with 4.5 mg·L-1 BA and 1.0 mg·L-1 NAA was found optimal for induction of callus from leaf explants. Callus regenerated shoots when transferred to MS medium with 2.5 mg·L-1 BA and 0.1 mg·L-1 NAA. The regeneration percentage as well as number of shoots per cm2 of callus was greatly improved by addition of ADS at a concentration of 3.0 mg·L-1. Regenerated shoots rooted within 20 days following transfer to half-strength MS medium with 0.1 mg·L-1 NAA. Plantlets were acclimatized under glasshouse conditions with 80% to 85% survival. Randomly selected 30 individual calliclones were subjected to field trial with wild-type parent in randomized block design, replicated three times with 90% survival for two successive years. Characterization of these calliclones for essential oil yield and quality traits demonstrated induction of variability in all the characteristics examined in negative and positive directions in comparison with the wild-type parent. This screening led to the identification of somaclone B22, which out-yielded the wild-type parent as well as the rest of the somaclones. The quality of the essential oil of B22 was similar to that of the parent. Chemical names used: N6-benzyladenine (BA); naphthalene acetic acid (NAA); adenine di-sulphate (ADS).
Manganese Toxicity in Watermelon as Affected by Lime and Compost Amended to a Hawaiian Acid Oxisol
Authors: Hue Nguyen V. , Mai Yvonne
Published: February 2019

Manganese (Mn) toxicity in crops is a serious problem in Hawaii, especially Kauai and Oahu, where most soils are highly weathered. To devise a management strategy to control Mn toxicity, a greenhouse experiment was conducted on an acid (pH 4.4) Oxisol (Wahiawa series) having 15g·kg-1 total Mn. Factorial combinations of lime (0, 2.0, and 4.0 g·kg-1 CaCO3) and two composts (made from chicken manure and from sewage sludge at 0, 5, and 10 g·kg-1) were applied to the soil, which was subsequently planted to watermelon (Citrullus lanatus Thunb. `Crimson Sweet'). Our preliminary results showed that: 1) liming reduced Mn extractability and phytoavailability, but the reduction in Mn per unit increase in pH was much less than predicted by theory; 2) for good watermelon growth, soluble Mn, as extracted by the saturated paste method, should be <2.0 mg·L-1 corresponding to a soil pH >5.7; 3) unlike the saturated-paste extractable Mn, the Mehlich3-extractable Mn varied less with pH in a given soil series than between soil series; 4) effects of composts on Mn toxicity varied with compost properties, especially their Ca content and pH altering capacity; and 5) the diagnostic criteria for Mn toxicity in watermelon are tentatively proposed as: leaf Mn >1000 mg·kg-1 and leaf Ca/Mn ratio (g·g-1) <25.
Response of Rabbiteye Blueberry (Vaccinium ashei Reade) to the Growth Regulators CPPU and Gibberellic Acid
Authors: NeSmith D. Scott
Published: February 2019

Experiments were conducted during 1999 and 2000 at Griffin, Ga., with rabbiteye blueberries (Vaccinium ashei Reade) to determine how the growth regulator CPPU affected fruit set, berry size, and yield. CPPU (applied at two different timings) was used alone, and in conjunction with GA3 on mature, field-grown `Tifblue' plants. A control treatment without either growth regulator was also included. The CPPU concentration used was 10 mg·L-1 (a single application per treatment), and the GA3 concentration used was 200 mg·L-1 (two applications per treatment). Results from both years showed a positive benefit of CPPU with respect to fruit set and berry size, especially in the absence of GA3. Depending on timing, berry number per plant was increased by more than 200% in 1999 using CPPU. Berry size increases of more than 30% occurred in 2000 when CPPU alone was applied at 17 d after flowering (DAF). CPPU did not increase berry size of GA3-treated plants in either year. Total yield per plant during 2000 was 5.0, 7.1, and 8.3 kg for control, CPPU applied 7 DAF, and CPPU applied 17 DAF treatments, respectively, without GA3. While CPPU did substantially increase fruit set, berry size, and yield of `Tifblue', there was a notable delay in fruit ripening. These results suggest that CPPU may be useful for increasing yield of rabbiteye blueberries under conditions of inadequate fruit set (such as occurs in much of the Southeast), but a delay in ripening will likely result. Chemical names used: N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU); gibberellic acid (GA3).
In Vitro Propagation of Three Species of Columnar Cacti from the Sonoran Desert
Authors: Pérez-Molphe-Balch Eugenio , Pérez-Reyes Martha Evelia , Dávila-Figueroa Carlos Antonio , Villalobos-Amador Enrique
Published: February 2019

In vitro propagation systems were developed for Carnegiea gigantea (Engelm.) Britt & Rose, Pachycereus pringlei (Berger) Britt & Rose and Stenocereus thurberi (Engelm.) Buxb, three North American species of columnar cacti. In vitro germinated seedlings were used as a source of explants. Multiple shoot formation from areoles was achieved for three types of explants (apical, lateral, and transverse) cultured on Murashige and Skoog (MS) basal media supplemented with 3% sucrose, 10 g·L-1 agar and various treatments with growth regulators. The highest shoot production efficiency for C. gigantea was obtained on transverse explants cultured on a medium with 2 mg·μmL-1 (8.87 μm) BA, where 5.3 shoots per explant were obtained. In P. pringlei and S. thurberi the best response was obtained using transverse explants on medium with 1 mg·L-1 (4.44 μm) BA (3.8 and 4.3 shoots per explant, respectively). Rooting of the in vitro generated shoots was achieved most efficiently on MS basal media with 3% sucrose, 10 g·L-1 agar and 1 mg·L-1 (4.9 μm) indole-3-butyric acid. Rooting frequencies were 92%, 88%, and 96% for C. gigantea, P. pringlei and S. thurberi, respectively, and the frequency of survival of the plants once transferred to soil was 86% on average. Chemical name used: benzyladenine (BA).
Tissue Moisture Loss during Sample Preparation Lowers Exotherm Temperatures in Dormant Grape Buds
Authors: Kovács László G. , Du Guoqiang , Ding Pinghai
Published: February 2019

Grapevine cold hardiness is often assessed with differential thermal analysis (DTA) of excised dormant buds. Such small tissues are prone to rapid dehydration when exposed to air during sample preparation. We show that excised buds of grape cultivars `Vignoles' and `Norton' lose as much as 6.3% and 2.9% of their total water content, respectively, during a two-minute exposure to air at 24 °C. In order to assess the impact of moisture loss on cold hardiness measurements, we prepared dormant bud samples with reduced water content and subjected them to DTA. The results demonstrate a positive correlation between average gross bud water content and median low temperature exotherm (LTEmean). In `Vignoles' and `Norton' buds, a 6.5% and a 4.3% reduction in gross water content, respectively, were sufficient to result in lower LTE temperatures (P < 0.001). The data suggest that even moderate dehydration of excised grape buds may influence the results of cold hardiness assessment by DTA. It is important that investigators be vigilant to the potential artifacts that can arise during sample preparation in order to ensure that the LTE temperatures of samples reliably characterize the cold hardiness of field populations.