bluuebunny/crossref_metadata_2025 huggingface dataset:
Responsiveness of Three Tayota (Sechium edule) Types to Gibberellic Acid Treatment
Authors: Morales-Payan J. P.
Published: January 2019

Container experiments were conducted in the Dominican Republic to determine the effects of gibberellic acid applications on the `White', `Green', and `Spiny Green' tayota (Sechium edule) Dominican types. Young plants (25 cm in length) of the three types were sprayed with aqueous solutions of gibberellic acid at rates 0, 50, 100, 150, and 200 parts per million. A completely randomized design with seven replications was utilized. Plant height and shoot dry weight were determined 30 days after treatment and resulting data was subjected to analysis of variance and regression analysis. Gibberellic acid treatment significantly increased tayota shoot dry weight and stem elongation. Both variables responded with similar patterns to gibberellic acid application. A linear regression (Y = 39.82 + 0.214 X, r2 0.95) described stem elongation as a function of gibberellic acid rates. Results show that gibberellic acid can be effectively used in either tayota type to promote early stem elongation. From a practical standpoint, due to the climbing nature of Sechium edulis, rapid stem elongation could be instrumental in a more rapid establishment of the crop vines in the trellis system, as well as to provide the crop with an advantage on weeds competing for light during the usually critical early growth stages.
Nitrogen Assimilation and Biomass Yield of Winter Cover Crops Used in Sustainable Horticultural Crop Production
Authors: Singh Bharat P. , Sainju Upendra M. , Whitehead Wayne F.
Published: January 2019

Cover crops are planted during winter to prevent soil erosion, improve soil quality, and supply nutrients to the subsequent spring crops. In a 2-year study, three winter cover crops were compared for their nitrogen assimilation and biomass yielding ability. The experimental design was randomized complete block replicated four times with cereal rye, hairy vetch, crimson clover, and a fallow control comprising the treatments. Cover crop roots were well distributed from 1 to 50 cm of soil depth and increased from fall to spring as temperature increased. There was greater reduction in soil inorganic N during fall and winter in cover crop plots compared to control. Early season soil NO–3 concentration was lower in rye than crimson clover or hairy vetch. The amount of N assimilated by hairy vetch and crimson clover was significantly greater than cereal rye or control. There was no difference in the biomass yield of the three cover crops during the first year, but cereal rye and crimson clover produced significantly greater biomass than hairy vetch during the second year. The results suggest that cereal rye is more suited for preventing leaching of residual N from the preceding summer crop, while the two legumes can supply more N to the following crop.
Sustainable Production of Honeydew and Muskmelon in Western Mexico
Authors: Farias-Larios J. , Michel-Rosales A.
Published: January 2019

In Western Mexico, melon production depends on high-input systems to maximize yield and product quality. Tillage, plasticulture, fumigation with methyl bromide, and fertigation, are the principal management practices in these systems. However, at present several problems has been found: pests as sweetpotato whitefly (Bemisia tabaci Gennadius), aphids (Myzus and Aphis), leafminer (Liryomiza sativae); diseases as Fusarium, Verticilium, and Pseudoperenospora, and weeds demand high pesticide utilization and labor. There is a growing demand for alternative cultural practices, with an emphasis on reducing off-farm input labor and chemicals. Our research is based on use of organic mulches, such as: rice straw, mature maize leaves, banana leaves, sugarcane bagasse, coconut leaves, and living mulches with annual legume cover crop in melons with crop rotation, such as: Canavalia, Stilozobium, Crotalaria, and Clitoria species. Also, inoculations with mycorrhizal arbuscular fungi for honeydew and cantaloupe melon seedlings production are been assayed in greenhouse conditions for a transplant system. The use of life barriers with sorghum, marigold, and other aromatic native plants in conjunction with a colored yellow systems traps for monitoring pests is being studied as well. While that the pest control is based in commercial formulations of Beauveria bassiana for biological control. The first results of this research show that the Glomus intraradices, G. fasciculatum, G. etunicatum, and G. mosseae reached 38.5%, 33.5%, 27.0%, and 31.0% of root infection levels, respectively. Honeydew melons production with rice and corn straw mulches shows an beneficial effect with 113.30 and 111.20 kg/plot of 10 m2 compared with bare soil with 100.20 kg. The proposed system likely also lowers production cost and is applicable to small- and large-scale melon production.
Molecular Markers Linked to Phytophthora fragariae Resistance Genes in Strawberry
Authors: Haymes K.M. , Hokanson S.C. , Salazar K. , Maas J.
Published: January 2019

The commercial strawberry (Fragaria × ananassa Duch.) is susceptible to red stele root rot caused by the fungus Phytophthora fragariae Hickman var. fragariae. Characteristics of the disease are the reddened steles and “rat tail” appearance of the roots. Infected plants are dwarfed, exhibit wilting, and eventually die. Red stele resistance in strawberries and virulence of P. fragariae behave according to the gene-for-gene system. Resistance genes and their corresponding avirulence genes have been identified by screening plant roots for infection. The goal of this international research project with CPRO-DLO, The Netherlands, is to develop highly specific molecular markers for various Rpf resistance genes (Rpf1, Rpf2, Rpf3, and Rpf6) that confer resistance against P. fragariae. Bulked Segregant Analysis was used to identify RAPD and AFLP markers putatively linked to P. fragariae resistance genes. The bulked DNAs representing subsets of three F1 populations that segregated monogenically for either resistance or susceptibility to P. fragariae. The map of these Rpf loci was generated using JoinMap®. The RAPD markers linked to the resistance genes are being converted into SCAR markers, while the AFLP markers will be used as probes for the detection of P. fragariae. The application of the molecular markers linked to resistance genes will have direct applicability to strawberry breeding programs. Marker-facilitated selection of these resistance genes would allow an efficient means in the screening and selection of plant material containing these genes and help in the pyramiding for resistance to P. fragariae. Genetic improvement of the strawberry by the ability to pyramid resistance genes will contribute to the productivity of the strawberry industry worldwide.
Identification of a Source of Resistance to Cherry Leaf Spot
Authors: Downey S.L. , Karle R. , Iezzoni A.F. , Jones A.L.
Published: January 2019

Cherry leaf spot caused by Blumeriella jaapii (Rhem) Arx. is a major fungal disease of sour cherry in most of the world's sour cherry production areas. This fungus causes premature defoliation, which, in conjunction with low temperature winter injury, can result in death of limbs and entire trees. `Montmorency', the only major sour cherry cultivar grown in the United States, is highly susceptible to this fungus and numerous fungicides are required to prevent this disease. In 1996, sour cherry seedlings and GI 148-1, a triploid hybrid developed in Germany from the cross sour cherry (Prunus cerasus Schattenmorelle) × P. canescens (Schmidt and Gruppe 1988 HortScience 23: 112), were inoculated with spores of B. jaapii obtained from infected sour cherry leaves in the orchard. Lesion counts were taken on days 7 and 14 and the number of lesions per cm2 was calculated. This experiment was repeated in 1997, including a full sibling of GI 148-1, GI 148-2. Sour cherry and GI 148-2 were highly susceptible to cherry leaf spot. Within 14 days, these selections exhibited an average of 19.4 and 5.4 necrotic lesions per cm2 respectively, sporulation, chlorosis, and eventually leaf drop. In contrast, GI 148-1 had significantly fewer lesions on average (1.4 lesions per cm2), no apparent sporulation, chlorosis or leaf drop. Different reactions exhibited by siblings GI 148-1 and GI 148-2 suggest that the resistance gene(s) in 148-1 are on the P. canescens chromosome(s), not from the sour cherry parent, and that the P. canescens parent was not homozygous. GI 148-1 is currently being used in a backcross breeding program to develop resistant varieties.
Inheritance of Resistance to the Southern Root-knot Nematode in Capsicum chinense Jacq.
Authors: Fery R.L. , Thies J.A.
Published: January 2019

A series of greenhouse tests were conducted to compare the level of resistance to the southern root-knot nematode (Meloidogyne incognita) exhibited by recently released Capsicum chinense germplasm lines to the level of resistance exhibited by C. annuum cultivars, to determine the inheritance of the resistance in C. chinense, and to determine genetic relationship between the resistances exhibited by C. chinense and C. annuum. The results of a replicated test indicated that the level of resistances exhibited by the recently released C. chinense germplasm lines PA-353, PA-398, and PA-426 is equal to the level of resistances exhibited by the resistant C. annuum cultivars Mississippi Nemaheart and Carolina Cayenne. Evaluation of parental, F1, F2, and backcross populations of the cross PA-426 × PA-350 indicated that the resistance in C. chinense is conditioned by a single dominant gene. The results of an allelism test indicated that this dominant gene is allelic to the N gene that conditions southern root-knot nematode resistance in the C. annuum cultivar Carolina Cayenne. The availability of a simply inherited source of outstanding resistance makes breeding for southern root-knot nematode resistance a viable objective in C. chinense breeding programs. This objective should be readily obtained by the application of conventional plant breeding methodologies.
Influence of Mycorrhizal Fungi on Growth and Nutrient Uptake of Micropropagated Guava Plantlets (Psidium guajava L.) during Acclimatization and Plant Establishment
Authors: Estrada-Luna Andrés A. , Davies Fred T. , Egilla Jonathan N.
Published: January 2019

The effect of mycorrhizal fungi on growth and nutrient uptake during acclimatization and plant establishment of micropropagated guava plantlets (Psidium guajava L. cv. Media China) was determined. Half of the plantlets were inoculated with the endomycorrhizae isolate ZAC-19 and grown in a glasshouse for 18 weeks. The isolate ZAC-19 was collected from the Chihuahuan Desert in Zacatecas State, Mexico, and is a mixed isolate containing Glomus etunicatum and unknown Glomus spp. Plantlets were fertilized with modified Long Ashton nutrient solution containing 11 μg P/ml. Shoot length, leaf area, leaf number, and dry mass partitioning were positively affected by mycorrhizae compared to noninoculated plantlets; however, noninoculated plantlets had greater leaf area ratios and specific leaf area. Mycorrhizal plantlets generally had increased leaf tissue mineral levels, particularly P, Mg, Cu, and Mo. However, noncolonized plantlets had higher N, K, and Mn. At the end of the experiment, roots of inoculated guava plantlets had colonization levels of 94.3%.
Maryland's Home and Garden Information Center: Helping Residents Solve Pest, Plant, and Landscape Problems
Authors: Traunfeld J.H. , Clement D.L. , Malinoski M.K. , Bosmans R.V.
Published: January 2019

The Home and Garden Information Center was created by the Univ. of Maryland Cooperative Extension Service in 1989 to relieve county-based faculty of the growing burden of client requests for help in the home horticulture area. The Center inter-disciplinary staff includes four regional specialists, phone consultants and office support personnel. The Center's twin goals are to educate residents to make wise decisions regarding horticultural practices and pesticide and fertilizer use and to help clients self-diagnose their pest and plant problems. These goals are achieved through a variety of outreach methods and advanced technologies. A conversant phone system allows residents toll-free access (24 hours a day) to pre-recorded, self-help, problem diagnostic tapes. Horticulture consultants are available Monday through Friday, 8 a.m.–1 p.m., to provide personalized phone service to individual clients. The phone system has handled over 320,000 calls in 8 years. A 1997 phone survey showed a client satisfaction rating of over 90%. Center faculty produces a well-received Master Gardener Handbook with extensive diagnostic keys and writes phone tapes and newspaper articles. The “IPM Series” of peer-reviewed fact sheets, enables clients to use diagnostic keys to identify and solve plant problems. Residents can also access information through the Center's web site which includes updated subject matter tips, and “pages” for the Master Gardener program, Bay Issues and plant diagnostic keys. Center faculty also helps to train phone consultants, county horticulture consultants, and Master Gardeners.
Below-ground Pot-in-Pot (PIP) System and Substrate Moisture Regimen Affect Growth of Two Desert Trees
Authors: Martin Chris A. , Bhattacharya S.
Published: January 2019

Acacia smalli (sweet acacia) and Cercidium praecox (palo brea) trees were grown during June–Oct. 1997 outdoors in full sun in 19-L containers positioned either PIP or above ground on the soil surface. The 38-L PIP holder containers were placed in the ground. Cyclic pulses of water were controlled by soil moisture sensors interfaced with electronic solenoid irrigation valves. Rooting substrate water potentials at 20 cm below the substrate surface and 10 cm inside the container wall were consistently maintained at either >–0.01 MPa (wet) or between –0.02 and –0.03 MPa (dry) for both above ground and PIP container substrates. Less than 1.25 cm of rainfall occurred during the study period. No incidences of rooting-out were observed with PIP trees. Maximum root-zone temperatures of PIP containers were 19 °C lower than temperatures measures in substrate of aboveground containers. Growth of both species was stimulated by the wet substrate regimen compared with the dry regimen. Positioning trees in a below-ground PIP configuration under the wet substrate regimen stimulated growth of sweet acacia compared with the PIP dry regimen. The PIP configuration did not affect growth of palo brea trees.
Factsheet Database: A Comprehensive Collection of Publications for the United States and Canada
Authors: Rhodus Tim
Published: January 2019

A full-text searchable database is available through the Internet that captures factsheets, bulletins, and other Extension publications related to horticultural and agronomic crop production and culture. Electronically accessable information from Extension in 50 different colleges and universities across the United States and Canada was indexed by a robot software program and provides clients with access to over 14,000 publications. This database represent the most concentrated source of plant-related information available for answering questions, developing outreach programs, or assisting individuals to learn about plants. Information can be search gloabally or limited to regional searches, e.g., Midwest, Northeast, Southeast, Southwest, West (including Hawaii), North Central, and Alaska, plus Canada. The address for the web site is: www.hcs.ohio-state.edu/factsheet.html.
Creation and Use of a Video as an Educational Tool
Authors: Olson William H. , Pickel Carolyn
Published: January 2019

Two Smith–Lever IPM Grants provided the funds to develop and disseminate information in an educational video about Walnut Husk Fly (WHF). The video was produced as a new way of conveying information about the techniques available to control WHF. Helping clientele implement new information on treatment timing was also a goal. The video was shown to 1154 clientele at 16 educational meetings. Fifteen regional trials were conducted across California to demonstrate the techniques illustrated in the video. Three-hundred-and-twenty-four clientele took a WHF quiz before and after viewing the video. Test results improved by 83%. A questionnaire indicated the video was a better format than a slide presentation for learning new information. Clientele particularly liked the review section at the end of the video. Seventy-five clientele participating in a postharvest telephone interview indicated that the information in the video helped them control WHF. Sixty-two percent used the new techniques described and 65% felt that the information presented improved their treatment timing. As a result of using information presented in the video, both the average number of treatments and insect damage was reduced. This 2-year project trained clientele representing over 40,000 acres of walnuts. Each Cooperative Extension office and IPM Advisor was given a copy of the video. In addition, over 70 copies of the video have been sold, several to pesticide companies for training of their pest control advisors.
Development of an Undergraduate Curriculum in Landscape Contracting
Authors: McDuffie Robert F. , Lyons Robert E.
Published: January 2019

Introducing a new curriculum option has led to greater student enrollment, more highly qualified students entering the curriculum, and better relations with and support from an expanding landscape industry. Student skills development, and enthusiasm has been enhanced by contemporary computer facilities, retooled instructional practices, new courses, strong ties to the industry, required internship, and an active post-graduation placement program. Justification for this option as well as specific details will be discussed.
Influence of Mechanical Shoot Positioning on Fruit Exposure, Yield, and Fruit Quality of `Concord' Grapevines
Authors: Zabadal Thomas J. , VanEe Gary R. , Dittmer Thomas W. , Ledebuhr Richard L.
Published: January 2019

`Concord' grapes grown in cool climates often encounter fruit maturity problems relative to desired processor standards. Exposure of grape clusters to sunlight may promote fruit maturity. A mechanical device for reorienting shoots on grapevines to increase fruit exposure was evaluated on `Concord' grapevines, which had been managed with Hudson River Umbrella training and balance-pruned to retain 44 nodes per kilogram of cane prunings. Three times of positioning and combinations of these times were evaluated for a 3-year period. Positioning consistently increased fruit exposure. Increases in fruit soluble solids were dependent upon the year and the time of positioning. Excessive reduction of leaf area resulting from some treatments is suggested as a factor depressing fruit soluble solids. The value of this approach to mechanical shoot positioning for enhancing fruit maturity depends upon the seasonal influence on grapevine canopy development. When excessive canopy develops, mechanical shoot positioning is likely to enhance fruit maturity.
Quantifying the Chilling Status of Grapevines and the Response to Dormancy-breaking Chemicals in the Coachella Valley of California
Authors: Dokoozlian N.K.
Published: January 2019

A method to quantify the chilling status of grapevines grown in a desert region, in order to better predict vine response to dormancy-breaking chemicals, was examined. Chilling status was determined by calculating the ratio between exposure to chilling temperatures (hours ≤7C) and chill-negating temperatures (hours ≥20C) from the beginning of the dormant period (1 Nov.) to the date of pruning (mid-December). A 6-year field study (1991 to 1996) compared the budbreak of untreated vines, and vines treated with H2CN2 (2% v/v) immediately after pruning, exposed to a range of chill:chill negation ratios resulting from yearly variations in environmental conditions. Budbreak was delayed, and total budbreak reduced, when the chill:chill negation ratio was <0.5. In contrast, rapid and complete budbreak was observed when the chill:chill negation ratio was >2. The standard dormancy-breaking treatment in this region, 2% (v/v) H2CN2, provided acceptable budbreak when the chill:chill negation ratio was near 1. Higher concentrations of H2CN2 were needed when the chill:chill negation ratio fell below 1, while H2CN2 could be reduced when the chill:chill negation ratio was 2 or more.
Temperature Response of Whole-plant CO2 Exchange Rates of Magnolia (Magnolia grandiflora L.)
Authors: van Iersel Marc W. , Lindstrom Orville M.
Published: January 2019

Photosynthesis and respiration temperature-response curves are useful in predicting the ability of plants to perform under different environmental conditions. Whole crop CO2 exchange of two groups of magnolia `Greenback' plants was measured over a 26 °C temperature range. Net photosynthesis (Pnet) increased from 2 to 17% C and decreased again at higher temperatures. The Q10 for Pnet decreased from ≈4 at 6 °C to 0.5 at 24 °C. The decrease in Pnet at temperatures over 17 °C was caused by a rapid increase in dark respiration (Rdark) with increasing temperature. The Q10 for Rdark was estimated by fitting an exponential curve to data, resulting in a temperature-independent Q10 of 2.8. Gross photosynthesis (Pgross), estimated as the sum of Rdark and Pnet, increased over the entire temperature range (up to 25 °C). The Q10 for Pgross decreased with increasing temperature, but remained higher than 1. The data suggest that high respiration rates may be the limiting factor for growth of magnolia exposed to high temperatures, since it may result in a net carbon loss from the plants. At temperatures below 5 °C, both Pnet and Rdark become low and the net CO2 exchange of the plants would be expected to be minimal.
Effect of Split Applications of GA3 on Flowerbud Density of Mature Peach Trees
Authors: Howard S. , Taylor B.H.
Published: January 2019

The effect of divided GA3 applications on flowerbud density was investigated using mature `Redhaven' and `Sweet Sue' peach trees treated at 6, 12, and 24 g/acre in 1994 and `Redhaven' and `Loring', treated at 12, 24, and 48 g/acre in 1995. Flowerbud densities were found to be reduced, except in the cultivar Sweet Sue, which had poor vegetative vigor. The reduction averaged 10% for the 48 g/acre, single, and 32% for the split application of the same rate. For both `Loring' and `Redhaven', it was the basal most 10 cm that showed the largest effect of the split applications, flowerbud density was 86% (single) vs. 28% of control (split) for `Loring' and 94% vs. 42% for `Redhaven'. For the rest of the shoot the differences were not as marked, but were larger for the younger, more vigorous `Loring'. Vegetative bud densities were found to be increased in all cultivars, with the split applications showing a larger effect. The increases were most marked in the distal most 10 cm of the shoots, at the 48 g/acre rate densities were 127% vs. 195% of control for `Loring' and 159% vs. 233% for `Redhaven'. Other growth characteristics (node and blind node density, shoot length) were also evaluated, but significant changes were rarely found. Comparing the number of flower- and vegetative buds per node revealed that the GA3 applications were effective on nodes that had formed 10 to 15 nodes prior to the number of nodes present at spray application. The effect of split GA3 applications was visible on a larger number of nodes, showing that split applications were able to affect a larger portion of the continuously elongating shoot.
Herbicide Tolerance Of Transgenic `Stevens' Cranberry Plants Depends on the Test Environment
Authors: Zeldin Eric L. , Serres Rodney A. , McCown Brent H.
Published: January 2019

`Stevens' cranberry was genetically engineered to confer tolerance to the broad spectrum herbicide glufosinate. Initially, herbicide tolerance was verified by spraying greenhouse plants with the commercial formulation Liberty. Although one transformant showed significant tolerance, the tolerance level was below that required to kill goldenrod, a common weed of cranberry beds. This transformant was propagated and the plants established outdoors in a coldframe, yielding a growth form more typical of field-grown plants than that of greenhouse-grown plants. These plants, as well as untransformed cranberry and goldenrod plants, were sprayed with various levels of the herbicide. The transformed plants were not killed at glufosinate concentrations up to 1000 ppm, although delayed growth did occur. Some runner tip injury was observed at 500 ppm as well as widespread shoot tip death at higher levels. The above-ground parts of goldenrod plants were killed at 400 ppm with significant injury at 200 ppm. Untransformed cranberry plants were killed at 300 ppm and had extensive tip death even at 100 ppm. Transformed cranberry plants with confirmed “field” tolerance were re-established in the greenhouse and new vegetative growth was forced. When these plants were sprayed with glufosinate, significant shoot tip injury was observed at levels as low as 100 ppm. The degree of herbicide tolerance of transformed cranberry appears to be modulated by the growth environment, which may affect the expression of the inserted genes or the physiological sensitivity of the impacted tissues.
The Influence of Gibberellic Acid (GA) on Postharvest Pitting of Citrus
Authors: Petracek Peter D. , Dou Huating , Stover Ed
Published: January 2019

Postharvest pitting is a citrus peel disorder that is characterized by the physiological breakdown of oil glands and is caused by high temperature storage waxed fruit. Pitting can be controlled by low temperature storage (>10 °C) or application of waxes with high gas permeability. However, refrigeration is costly and often difficult to implement while waxes with higher gas permeabilities have gloss values that are considered to be insufficient for consumer acceptance. Consequently, packers would like to control or predict pitting incidence prior to postharvest stress. Pitting incidence within a grove can vary dramatically within a season despite comparable postharvest handling. Thus, peel susceptibility may be not only variable, but alterable. Peel physiology is readily altered by early-season application of GA, a method currently used to retard peel maturation. Since the influence of GA on postharvest pitting is not known, we examined the effect of early-season foliar-applications of GA on peel quality of `Fallglo' tangerines and white grapefruit. Fruit were harvested throughout the season, washed, coated with shellac-based wax, and stored at 21 °C and 93% RH. GA applied with a silicone surfactant retarded peel maturation as indicated by greener, firmer peels. Pitting incidence was typically less for GA-treated fruit during the initial days of storage. However, GA suppression of pitting did not always persist throughout storage. GA did not affect internal levels of O2, CO2, ethanol, or acetaldehyde or weight loss. While the effectiveness of GA was not consistent, the results suggest that GA application strategies could be developed to suppress pitting. Also, GA treatments may help define factors that determine fruit susceptibility to postharvest pitting.
Pre-plant Solarization Affects Bedding Plant Quality and Fresh Weight
Authors: Bell Michelle L. , McGovern Robert J. , McSorley Robert
Published: January 2019

A solarization study was initiated in Central West Florida whereby field plots, comprised of EauGallie fine sand known to be infested with Rhizoctonia solani and phytoparasitic nematodes, were covered with a double layer of 1.0-mil clear, low-density polyethylene mulch. The split-plot design consisted of 10 plots, five which were solarized for 6 weeks and five left untreated. Each plot was further subdivided into four 1.5 × 1.5-m subplots. On 14 Oct. 1997, 16 Impatiens wallerana `Accent Burgundy' were planted to each subplot. Pre- and post-plant drench treatments included the fungicide, fludioxonil; two biological control agents; and an untreated control. Individual plants and whole subplots were rated for stunting, chlorosis, and incidence of disease from R. solani (stem lesions, crown and shoot blight) twice weekly. Two months after planting, plant fresh weight by subplot was measured, plant quality was determined, roots and crowns were plated on selective media and visually evaluated for disease and root-knot nematode symptoms. Soil cores were taken prior to solarization, at planting, and at termination of the study for nematode identification and enumeration. Data presented will be limited to the combined plant fresh weights of subplots and to plant quality; disease symptoms were incorporated in quality ratings. Solarized plots had a 250% greater combined fresh weight than non-solarized plots. The lowest mean quality ratings for any subplot treatment within the solarized plots was significantly greater than the highest ratings of plants from any subplot treatment within the non-solarized treatment.
Low-maintenance AlternativeTurfgrass
Authors: Meyer Mary H.
Published: January 2019

Thirteen materials and two controls were evaluated for 3 years at two locations for color, cover, and overall rating as acceptable turf or lawn. 10' × 16' plots were maintained at 2”, 4”, and no mowings; two, one or no fall fertilizations; with no pesticide or irrigation. Best color ratings were the fine fescues; best cover a traditional mix of Kentucky bluegrass, fine fescues and perennial ryegrass (Sunnylawn mix); dryland ecology mix and fleur de lawn;best overall rating was Sunnylawn mix, fine fescue blend, and Ram I. Materials evaluated included: 378 and 45-3 buffalograss; `Alma' bluegrama;”No Mow”; 'Azay' sheep fescue; 'Discovery' hard fescue;dwarf sheep fescue; fine fescue blend; fleur de lawn; Dryland Ecology Mix; native grass and forb mix; Flowers and Flowers Elite;Super Short Mix; creeping alfalfa; Sunnylawn mix and `Ram I' KBG were used as controls.
Growth of Dracaena marginata and Spathiphyllum `Petite' in Spaghnum Peat and Coconut Coir Dust-based Growing Media
Authors: Stamps Robert H. , Evans Michael R.
Published: January 2019

Dracaena marginata Lam. and Spathiphyllum `Petite' were grown in three greenhouse growing media made with Philippine coconut (Cocos nucifera L.) coir dust (CD) or Canadian sphagnum peat (SP). Three soilless media [Cornell, Hybrid, Univ. of Florida #2 (UF-2)] were prepared using CD or SP and pine bark (PB), vermiculite (V), and/or perlite (P) in the following ratios (percent by volume): Cornell = 50 CD or SP:25 V:25 P; Hybrid = 40 CD or SP:30 V:30 PB; UF-2 = 50 CD or SP:50 PB. When most of the plants of each genus were of marketable size, plant root and top masses and grades were determined as well as plant top growth indices. For dracaena, there were interactions between medium component (CD/SP) and medium type for everything except mass and grades of roots. For Cornell mix, plant top growth index and grades were higher for SP- (SPM) than the CD-containing medium (CDM). However, masses were not different due to component. For Hybrid mix, only top mass was affected (CDM 12%> SPM). For UF-2, top plant index and top and total plant masses were higher for CDM than SPM by 10, 19 and 15%, respectively. Overall, plant masses were the same for all three mixes containing CD; however, top plant index and grades were higher for the Hybrid and UF-2 mixes than for Cornell. Using SP, plants in Cornell and Hybrid mixes generally outperformed those in UF-2. For spathiphyllum, there were no interactions and medium component only affected root ratings (CDM > SPM). Plant top, root and total masses and root ratings were higher for Cornell and Hybrid than for UF-2.
Genetic Diversity of Castanea pulia var. ozarkensis
Authors: Dane Fenny , Harrison Shona , Huang Hongwen
Published: January 2019

The genus Castanea includes several species, some of which, like the American chestnut (C. dentata) and chinkapin (C. pumila), are susceptible to chestnut blight, caused by the Asian fungus Cryphonectria parasitica. Blight spread throughout the natural range of the American chestnut, destroying several billion trees within the past 50 years. Although the plight of the American chestnut is well-known, the chinkapin has been neglected. Taxonomic studies indicated two varieties, the Ozark chinkapin, var. ozarkensis, limited to the Ozark Highlands of Arkansas, Missouri, and Oklahoma, and the Allegheny chinkapin, var. pumila, found from New Jersey to Florida and Texas. The genetic diversity within and between 11 geographic populations of the Ozark chinkapin was evaluated to provide baseline genetic information pertinent to the conservation and restoration of this species. Nuts or dormant buds of chinkapin trees were evaluated for isozyme and RAPD polymorphism. The genetic variability of the Ozark chinkapin populations was relatively high when compared to the American chestnut, and most of the diversity resides within the populations. Conservation considerations for restoration of the Ozark chinkapin will be discussed.
An S-locus Receptor Protein Kinase from Peach is Expressed Predominantly in Fruit and Responds Differently to Various External Stresses
Authors: Bassett C.L. , Nickerson M. , Artlip T.A. , Wisniewski M. , Gaouth A. El , Wilson C.
Published: January 2019

A receptor-like protein kinase (RLK) isolated from December peach bark (Ppsrlk1) was previously shown to have considerable homology to the S-locus class of RLKs associated with reproductive self-incompatibility. Unlike those RLKs, transcripts arising from Ppsrlk1 were not detectable in standard RNA blots. To determine the pattern of expression of this gene, RNAs from various peach tissues, some of which had been subjected to different stress treatments, were surveyed using Reverse Transcript-PCR (RT-PCR). Based on these results, select RNAs were further quantitated by Competitive PCR (C-PCR). RT-PCR of RNAs from seasonal peach bark revealed little change in the relative abundance of Ppsrlk1, although a slight decrease was noted in the RNAs from October and December bark. Expression of Ppsrlk1 in developing peach fruit peaked at stage II and declined thereafter from stage III and in the later stages of ripening. Ripe peach fruit subjected to 10 min UV treatment or wounding followed by application of a yeast biocontrol agent showed a further decline in Ppsrlk1 expression; C-PCR analysis of the wounded fruit indicated a five-fold difference in expression between wounded water controls and wounded fruit treated with the biocontrol agen 48 h after treatment. In bark and xylem tissues under water deficit conditions expression of Ppsrlk1 declined. In contrast, levels of Ppsrlk1 in leaves and roots increased. C-PCR of the root samples revealed a 50-fold increase in the transcript in response to water deficit.
Thermal Blast Shelling of Nuts
Authors: Smith D.A. , Harris H. , Norton J.D.
Published: January 2019

Thermal blast shelling has proven effective in removing the shells from filberts, chestnuts, almonds, pecans, and coconuts. Shells were completely removed from nuts and the nuts were blanched in a single operation. Thermal Blast shelling was accomplished with an apparatus that confined nuts in a pressure vessel, supplied intense heat for a short duration, then instantly opened the vessel to atmospheric pressure. The result was an explosion that blew the product from the vessel and simultaneously exploded the shell from the nut. Blanching was complete with all testa removed from kernel convolutions during the shelling of filberts, chestnuts, and almonds. Pecans required conditioning to an optimum moisture level and a heating medium comprised of superheated steam and air to avoid kernel damage.
Findings from a Three-year Crop Nutrient Study with Four Vegetable Crops in Dade Country, Florida
Authors: Lamberts Mary , O'Hair Stephen K. , Hanlon Edward , Hochmuth George
Published: January 2019

A 3-year replicated fertility trial with four vegetable crops was begun in the 1993–94 season to: a) determine crop nutrient requirements for four vegetable crops (bush bean, malanga (Xanthosoma caracu), potato, and sweet corn, and b) to develop and calibrate a soil testing procedure for the local calcareous soils. Soils were found to test medium to high for both phosphorus and potassium. Responses to nitrogen varied by crop. Specific results and follow up trials with growers will be discussed.
Presidedressing Soil Nitrate Testing (PSNT) Effective in Reducing N Fertilizer Use in Vegetable Production
Authors: Hartz T.K. , Bendixen W.E.
Published: January 2019

The utility of PSNT in determining N sidedress requirement of cool-season vegetables (broccoli, cauliflower, celery and lettuce) was evaluated in a total of 20 trials conducted in commercial fields in California in 1996–97. Fields were selected which had soil NO3-N concentration >20 mg·kg-1 at the time the cooperating grower made the first sidedress N application. The grower's fertility program was compared with two reduced N treatments, established by skipping either the first, or the first and second, sidedress N application. There were four replications of each N treatment, in a randomized block design. All fields were conventionally irrigated (sprinkler and/or furrow). Crop and soil N status was evaluated throughout the season. No yield or quality differences were observed in any field by skipping the first N sidedress; in only three fields was yield reduced by skipping two sidedress applications. Total crop N uptake varied little among N treatments in most fields, despite differences in seasonal N application of as much as 200 kg·ha–1. These results indicate that PSNT can reliably identify fields in which sidedress N application can be delayed or eliminated. A soil NO3-N “quick test” was evaluated and proved to be a practical on-farm method to determine soil NO3-N status.
Seed-piece Spacing Influences Yield, Size Distribution, Net Returns, and Stem and Tuber Density of Three Processing Potato Cultivars
Authors: Love Stephen L. , Thompson-Johns Asunta
Published: January 2019

Seed-piece spacing is an important economic consideration in the production of potatoes and optimum varies by cultivar and intended market. A study was designed to determine the influence of seed-piece spacing on yield, tuber size distribution, net returns and stem and tuber density of three processing potato cultivars. Seed tubers of cvs. Russet Burbank, Frontier Russet and Ranger Russet were planted 8, 15, 23, 31, 46, 61, 76, or 91 cm apart at two locations in 1988 and 1989. Total, marketable (U.S. No. 1), and mid-size (226–452 g tubers) yield, yield of five incremental size categories, net profits from a typical processing contract, and stem and tuber density (number per m of row) were determined. All three cultivars achieved highest total yields at the narrowest (8 cm) spacing. Marketable and mid-size yield were optimized between 15 and 31 cm depending on the cultivar. The size distribution of tubers shifted from a predominance of small tubers at the narrow spacing treatments to a predominance of large tubers at the wide spacing treatments. The rate of shift across spacing treatments was cultivar dependent. Russet Burbank showed a bimodal response to spacing for net returns with optimums at the 23- and 46-cm spacing treatments. Frontier Russet and Ranger Russet showed optimums at 23 cm. All three cultivars gave maximum mid-size yields at a stem density of 10.5–12.1 per m of row and a tuber density of 23.9–24.9 per m of row.
Low-level Irradiance during the Dark Period Prevents Photoperiodic-induced Tuberization of Potato
Authors: Yorio N.C. , Stutte G.W. , Wheeler R.M. , Ruffe L.M.
Published: January 2019

The threshold irradiance during the dark portion of a photoperiod required to inhibit tuberization of potato (Solanum tuberosum L.) was investigated. Two cultivars of potato (cv. Norland, an early maturing variety; cv. Russett Burbank, a late-maturing variety) were grown using nutrient film technique hydroponics in separate tests within a walk-in growth chamber under a normally tuber-inductive photoperiod (12-h light/12-h dark). Light period photosynthetic photon flux (PPF) was provided by either daylight fluorescent lamps (providing 150 μmol·m–2·s–1 PPF) or a combination of daylight fluorescent and metal halide lamps (providing 300 μmol·m–2·s–1 PPF). The chamber was configured with vertically hung shadecloth and a pair of 15-W cool-white fluorescent lamps mounted at one end of the chamber to provide a range of low irradiance during the dark period. The low irradiance treatments averaged 3.65, 0.43, 0.06, and <0.01 μmol·m–2·s–1 PPF for the entire 12-h “dark” period. Results showed that tuberization occurred around 23 DAP, regardless of cultivar or light period PPF for plants grown with 0.06 and <0.01 μmol·m–2·s–1 PPF during the dark period. Tuberization also occurred at around 30 DAP for cv. Norland grown with 0.43 μmol·m–2·s–1 PPF during the dark period. No tubers were formed for either cultivar grown with 3.65 μmol·m–2·s–1 PPF during the dark period. These results indicate that light levels <0.43 μmol·m–2·s–1 PPF do not influence photoperiodic induction of tuberization in potato.
Does Ethanol-induced Chilling Tolerance Affect the Antioxidant Systems of Cucumber Seedling Roots?
Authors: Boyd Windy A. , Jennings Paul H.
Published: January 2019

Previous experiments have shown that chilling-stressed cucumber seedlings treated with ethanol have greater chilling tolerance when compared to untreated seedlings. This chilling tolerance persists for a limited time (2-4 h) and, once lost, chilling tolerance can be re-induced by a second ethanol treatment. In all cases, greater chilling tolerance was measured as an increase in root growth and a decrease in lipid peroxidation and electrolyte leakage. This study was undertaken to determine whether antioxidant systems, which may help plants survive some environmental stresses, are affected by ethanol and/or chilling treatments. The relative activities of glutathione reductase (GR) and peroxidase (POX) of chilled and/or ethanol-treated seedlings were compared. GR activity was suppressed by the combination of any ethanol treatment and chilling when compared to the control. Upon re-warming, all ethanol treated groups exhibited higher GR activity than before chilling. POX activity was affected by the chill plus re-warming treatment in which a significant increase was seen in all treatment groups. Any group treated with ethanol had a lower POX activity than the control. POX activity stains, using non-denaturing PAGE, showed the appearance of three new bands in all treatment groups after the chill and rewarming. The increased intensity of the stain in the re-warmed groups supports the enzyme activity data mentioned above. Since ethanol treatment generally suppressed the enzyme activity after chilling, ethanol's possible role as a scavenger of reactive oxygen species will be discussed.
Calcium Uptake and Whole-plant Water Use Influence Pod Calcium Concentration in Green Bean Plants
Authors: Pomper Kirk W. , Grusak Michael A.
Published: January 2019

Understanding the mechanisms that regulate xylem transport of calcium (Ca) to green bean pods could allow approaches to increase pod Ca concentrations and enhance the nutritional value of edible pods. Using the green bean cultivars `Hystyle' and `Labrador', that exhibit high and low pod Ca levels respectively, we wished to determine whether observed differences in Ca concentration of stem xylem-sap were related to differences in whole-plant water uptake and Ca import. Well-watered greenhouse-grown plants, selected at flowering and at two stages of pod development, were placed in a growth chamber at a constant light intensity. Pot weight loss was measured to determine whole-plant water use and stem xylem exudate was subsequently collected from the severed base of the shoot. `Hystyle' displayed 50% higher Ca concentration in exudate than `Labrador' during pod development. Labrador showed 35% greater total water transport through the stem than `Hystyle'. Additional plants were used to determine total, long-term Ca uptake. No significant differences in total Ca were seen between cultivars at the three harvest dates. With whole-plant Ca uptake being equivalent, the results suggest that higher water uptake in `Labrador' led to a dilution of Ca in the xylem stream and thus less total Ca was transported to developing pods, relative to that in `Hystyle'. These results reveal that green bean varieties with low whole-plant water use have the potential to yield edible pods with elevated Ca content.
Reproductive Responses of Capsicum annuum to High Temperatures
Authors: Erickson Ami N. , Markhart Albert H.
Published: January 2019

Fruit yield reduction due to high temperatures has been widely observed in Solanaceous crops. Our past experiments have demonstrated that Capsicum annuum cultivars Ace and Bell Boy completely fail to produce fruit when grown at constant 33 °C. However, flowers are produced, continually. To determine which stages of flower development are sensitive to high temperatures, pepper buds, ranging in size from 1 mm to anthesis, were exposed to high temperatures for 6 hr, 48 hr, 5 days, or for the duration of the experiment. Fruit set for each bud size was determined. Exposure to high temperatures at anthesis and at the 2-mm size stage for 2 or more days significantly reduced fruit production. To determine whether inhibition of pollination, inhibition of fertilization, and/or injury to the female or male structures prevents fruit production at high temperatures, flowers from pepper cultivars Ace and Bell Boy were grown until flowers on the 8th or 9th node were 11 mm in length. Plants were divided between 25 °C and 33 °C constant growth chambers for 2 to 4 days until anthesis. At anthesis, flowers from both treatments were cross-pollinated in all combination, and crosses were equally divided between 33 or 25 °C growth chambers until fruit set or flowers abscised. All flower crosses resulted in 80% to 100% fruit set when post-pollination temperatures were 25 °C. However, post-pollination temperatures of 33 °C significantly reduced fruit production. Reduced fruit set by flowers exposed to high temperatures during anthesis and pollination is not a result of inviable pollen or ovule, but an inhibition of fertilization or initial fruit development.
Thermal Blast Peeling of Peppers
Authors: Smith D.A. , Harris H.
Published: January 2019

The skins of peppers are tightly attached to the flesh and do not readily separate by moderate scalding or steaming. In commercial canning operations, skin separation is achieved by immersion in hot caustic or by flaming. These treatments remove a substantial portion of edible pod tissue and cause tissue collapse and loss of product quality. Thermal blast peeling is a process whereby peels and blemishes are efficiently removed from produce by holding the produce for a brief period in a heated, closed vessel filled with superheated steam under elevated pressure while supplemental radiant heat is supplied by the vessel wall. This intense, dry heat superheats a film of moisture immediately underlying the peel tissue. The pressure within the vessel is then instantaneously reduced by opening the vessel. Steam within the vessel expands blowing the produce free of the vessel and simultaneously the superheated water in and immediately underlying the peel flashes to steam thus cleanly exploding the peel tissues from the produce. Pimiento peppers and jalapeno peppers were peeled by the Thermal blast process and compared to caustic peeled peppers. Product yields, Instron texture analysis, and color were compared in both the raw peeled fruit and in the canned peeled product. Volatile flavor profiles were analyzed by head space gas chromatography. Thermal blast-peeled peppers had firmer texture, thicker pod walls, and better color than caustic-peeled peppers. Thermal blast-peeled peppers had head space volatiles similar to unheated raw peppers.