bluuebunny/crossref_metadata_2025 huggingface dataset:
Suppression of Liverwort Growth in Containers by Cinnamic Aldehyde
Authors: Svenson Sven E.
Published: February 2019

Extensive growth of liverwort (typically Marchantia sp.) on the surface of the growing medium in plant containers is a serious problem in many nursery and greenhouse operations. A spray application of cinnamic aldehyde at 0%, 0.25%, 0.5%, or 1% a.i. was applied to uninfested 4-inch-diameter containers, and to containers infested with Marchantia polymorpha. Application to uninfested containers delayed liverwort establishment for an additional 1, 2, and 4 weeks at the 0.25%, 0.5%, and 1% applications rates, respectively, compared to the 0% control. Ten days after application, 0%, 70%, 95%, and 100% of liverwort thalli covering the growing medium surface of infested containers were killed by the 0%, 0.25%, 0.5%, or 1% application, respectively. However, only the 1% rate also killed the gemmae cups growing on the thalli surface. Regrowth of liverwort began 2, 3, and 5 weeks following application, respectively. Prevention of infestations is desirable, as dead liverworts are less attractive than live growth. No phytotoxicity symptoms were observed on Rhododendron growing in the treated containers.
Effects of Phosphorus Fertility Regimes and Smooth Pigweed (Amaranthus hybridus) and Common Purslane (Portulaca oleracea) Removal Times on Lettuce Yields
Authors: Santos Bielinski M. , Dusky Joan A. , Stall William M. , Shilling Donn G. , Bewick Thomas A.
Published: February 2019

The effects of different smooth pigweed and common purslane removal times and two phosphorus (P) fertility regimes were studied under field conditions. Head lettuce (cv. South Bay) in organic soils low in P fertility. Smooth pigweed and common purslane were grown at a density of 16 plants per 6 m of row (5.4 m2) and five removal times (0, 2, 4, 6, and 8 weeks) after lettuce emergence. Phosphorus (P) was applied broadcast (1200 kg P/ha) and banded 2 inches below each lettuce row (600 kg P/ha). Lettuce fresh weights were collected 8 weeks after emergence. When smooth pigweed was removed after 4 weeks, significant reductions (–17%) were observed for P banding. However, these reductions occurred after 2 weeks if P was broadcast. No significant differences were observed if removal was imposed later for P broadcast, whereas lettuce yields gradually decreased as removal time was delayed. These findings indicate that P banding can counteract the negative impact of smooth pigweed on lettuce and may allow farmers to delay weed control (if necessary) for another 2 weeks without significant yield reductions. Common purslane interference did not cause significant lettuce yield reductions as compared to the weed-free control for 6 weeks when P was banded, whereas this was true for P broadcast up to 4 weeks. Phosphorus fertility regime significantly influenced the period of weed interference of common purslane with lettuce, reducing its impact when P was banded.
Developing a Cyberserve Course
Authors: Relf Diane , Dorn Sheri , DeMarco Laurie , Dobbs Kate , Schnitzer Marcy
Published: February 2019

Through a CyberServe Grant, a WWW Home Page and student/community listserve were established as core communication tools for a special study taught Spring 1997, Hort 4984, Horticulture and the Community: Professional Growth through Volunteering. It incorporated the Blacksburg Electronic Village to easily put student volunteers and the community programs they worked with in direct contact with each other, allowing an exchange of ideas that made them equal partners in their endeavors. It provided direct access to valuable information to understand the principles and philosophy behind programming efforts for both students and community sites where they volunteered. It also was a recruiting tool to involve other students and the Horticulture Club in service-learning projects because students in the class could post “help” notices to entice classmates to participate in defined projects. It provided students with knowledge and experience in the role of the Internet in enhancing the quality of life in their communities. Information installed on the site included reading materials on Horticultural Therapy, children's gardening, community gardening, science education through gardening, and volunteering in these areas; community site descriptions and slides, program activities, goals of program participants, and materials from the program (i.e., selected first-grade drawings of their garden); students participating in the class and information about them; goals, objectives, and management information on the course; and links to relevant information from around the world to put the activities of the students in an international framework.
Using Interactive Multimedia to Enhance Student Access to Information on Plant Anatomy and Cell Biology
Authors: Geneve Robert L.
Published: February 2019

An interactive multimedia presentation was developed using authoring software (Authorware from Macromedia) to provide information on plant anatomy and cell biology. Our current course in growth and development of horticultural crops has limited time and lab facilities available for these subjects, yet a good foundation in this area is important to understanding growth and development. This software uses a variety of techniques, including color digital images, illustrations, cartoon animation, and video, to teach aspects of cell biology and different plant cell types. In addition, a review session allows students to interactively test their knowledge of the subject. The software was placed on a Dept. of Horticulture server that provided student access to a folder for course work. Students were able to access the software from anywhere on campus via the University network. Multiple students can use the software simultaneously. The approach of using a local server provided easy access and avoided some of the delays involved with viewing large (1 mb) images found when using the World Wide Web. It took students several weeks to complete the software's modules. Then, students completed an independent plant anatomy lab using the software for reference. Students were required to create a virtual notebook of labeled digital images captured from prepared microscope slides using a microscope attached with a digital camera and linked to a computer. Students found this approach to learning to be challenging, and initial feedback has been very positive.
New Horticulture Curriculum on Growing Media and Soil Amendment Available
Authors: Hood G.O.
Published: February 2019

Horticultural schools are always looking for fresh material for their classes. The Canadian Sphagnum Peat Moss Association (CSPMA) has developed a lesson plan entitled Growing Media and Soil Amendment that is ideal for horticultural or greenhouse management courses. The teaching plan includes terms and definitions on all types of peatmoss and commonly used terms related to the resource. It discusses characteristics and qualities of world peat resources as well as comparisons of physical, chemical, and biological properties of organic materials used in growth media and as soil amendments. In addition to the research information on peat and other soil amendments, the teaching plan addresses the environmental issues surrounding the use of wetlands, including peatlands and the effects of peat harvesting on the environment. The plan introduces students and instructors to the reclamation and restoration efforts that have been developed and used to preserve the harvested bogs in Canada. The curriculum is divided into two sections: one for the students, which includes handouts and one for the instructor, with more in-depth background information.
Reducing Irradiation Damage to `Arkin' Carambola
Authors: Miller W.R. , McDonald R.E.
Published: February 2019

Carambolas require quarantine treatment for security against the Caribbean fruit fly (Anastrepha suspensa Loew) (CFF) prior to shipment to certain domestic and export markets. Low-dose irradiation is effective for the control of CFF, but carambolas are susceptible to peel injury and quality deterioration at relatively low doses. Peel discoloration, stem-end breakdown, and fruit shriveling were reduced when carambolas were irradiated in polystyrene clam shell packs at 0.15 or 0.5 kGy compared with irradiation in conventional fiberboard packaging. Some pitting was observed at 5°C, but not at higher storage temperatures. Irradiation of carambolas in clam shell packaging increases the tolerance of fruit to peel and quality disorders, and improves the potential of irradiation as a quarantine treatment.
Effectiveness of High-temperature Forced Air on Reducing Growth of Green Mold (Penicillium digitatum Sacc.) in Grapefruit
Authors: Shellie Krista C.
Published: February 2019

Export and domestic marketing of grapefruit (Citrus paradisi Macf.) can be limited by phytosanitary barriers against fruit fly species and growth of decay organisms, especially green mold (Penicillium digitatum Sacc.), during the marketing process. The objective of this research was to identify whether the dose of high-temperature forced air that providing quarantine security against Mexican fruit fly could also beneficially control the growth of green mold during subsequent storage. `Rio Red' grapefruit were harvested four times in 1995 and nine times in 1996 and challenge-inoculated with 10 L of a 1 × 106 spores/ml spore solution (10,000 spores) of green mold before or after exposure to 46°C forced air for 300 min. Control fruit were challenge-inoculated but not exposed to the heat treatment. The growth of green mold was quantified by measuring lesion diameter after 3 days of storage at 23°C, 80% RH. Grapefruit inoculated prior to the heat treatment developed significantly smaller lesions than fruit inoculated after the heat treatment or fruit not exposed to a heat treatment. The average lesion diameter of fruit inoculated prior to the heat treatment was 2.5 and 0.9 cm, respectively, in 1995 and 1996. The average lesion diameter of fruit inoculated after the heat treatment was similar to non heat-treated, control fruit. Lesion diameter of control and post heat-challenged fruit were 6.4 and 6.1 cm in 1995 and 5.7 and 5.3 cm in 1996. Results suggest reduction in decay be attributed to alteration in the pathogenicity of green mold after exposure to the heat treatment rather than an altered resistance of the fruit to the pathogen.
Use of Growth Regulators Improves Germination of `Jalapeno M' Chile at Supraoptimal Temperatures
Authors: Carter Anne K. , Stevens Roseann A.
Published: February 2019

Thermoinhibition has been observed in chile (Capsicum annuum L.) transplants grown in greenhouses in southern climates. Hormones have been used successfully as a treatment for thermoinhibition in other vegetable crops. This experiment examined the effects of Ethrel and Release as treatments to improve germination in chile seeds germinated at a supraoptimal temperature. Seeds of `Jalapeno M' were soaked in solutions of Ethrel at 1.75, 3.0, 7.0, or 10.5 mM concentration or Release at 0.50, 1.0, 2.0, or 3.0 mM concentration, or 16 different combinations of the two growth regulators. The seeds were soaked in the treatment solutions for 40 hours at 25°C. A H2O-soaked and a non-soaked control were also included. Afterwards, the seeds were rinsed, dried, then germinated in 25°C or 40°C incubators. At 25°C, all treatments reached 98% germination or better after 10 days, indicating that none of the treatments were detrimental to germination. At 40C, germination percentages amongtreatments ranged from 0% for the nonsoaked control to 90% for a Release–Ethrel combination. Generally, the combination treatments resulted in germination percentages higher than either Ethrel or Release used alone. Results of these tests in petri dishes indicate the possibility of growth regulators being used to overcome thermoinhibition in chile. A greenhouse study is underway.
Evaluation of Apple Scab Resistance of Malus sieversii Populations from Central Asia
Authors: Aldwinckle H.S. , Forsline P.L. , Gustafson H.L. , Hokanson S.C.
Published: February 2019

Resistance to apple scab (Venturia inaequalis) in apple cultivar breeding has been derived mainly from the Vf gene from Malus floribunda 821, which introgresses horticulturally unfavorable characters. M. sieversii, now thought to be the primary progenitor of M. × domestica, grows wild in many diverse habitats in Central Asia and can have fruit quality comparable to commercial cultivars. Since 1989, four major collections of M. sieversii have been made in Central Asia, where scab is endemic. Some seed collections have been made from trees with superior fruit, that were not infected with scab. Over a 6-year period, 3000 seedlings from 220 wild M. sieversii trees representing 10 diverse ecosystems in Kazakstan, Uzbekistan, Kyrgyzstan, and Tajikistan have been inoculated with conidia of five races and two wild types of V. inaequalis. Suspensions (270,000 conidia/ml) were applied to 4- to 8-leaved seedlings, which were incubated for 48 h at 19°C with constant leaf wetness. Symptoms for three resistant reactions were assessed 2 to 4 weeks after inoculation: A = chlorosis with crinkling (Vf type reaction); B = stellate necrotic lesions (Vr type reaction), and N = large necrotic areas (uncharacterized resistant reaction). Results indicated that nearly 20% of the seedlings showed one or more of the resistant reactions. The range of resistance within seedling populations from each of the 220 single-tree sources ranged from 0% to 75%. Significant differences existed among seedlings from each of the ecosystems. Most resistance reactions appeared to be similar to those observed for Vr from “Russian seedling.” Resistant selections with superior horticultural traits may constitute a genepool for increased efficiency of breeding scab-resistant cvs. This genepool may also be useful to address the breakdown of resistance to V. inaequalis race 6.
Simple Sequence Repeat (SSR) Variation in a Collection of Malus Species and Hybrids
Authors: Hokanson Stan C. , Szewc-McFadden Amy K. , Lamboy Warren F. , McFerson James R.
Published: February 2019

A diverse collection of 133 Malus species and hybrids from the USDA Plant Genetic Resources Unit's core subset collection was screened with five simple sequence repeat (SSR) primer pairs in order to determine genetic identities and overall levels of genetic variation. The number of amplification products (alleles) per locus (primer pair) in this collection ranged from 6 to 39, with some genotypes showing complex banding patterns of up to four products per locus, suggesting that duplication events may have occurred within the genome. Five primer sets unequivocally differentiated all but 10 pairs of genotypes in the collection, with seven of these 10 being pairs of the same species. Within three of the species holdings surveyed, M. honanensis, M. sargentii, and M. sikkimensis, no genetic variation was revealed with the SSR markers. The discrimination power for the combined loci in this collection was nearly one, which indicates that the likelihood of two genetically different accessions sharing the same alleles at all the loci included in this study would be nearly impossible. Coupled with results from a previous survey of M. × domestica accessions, this finding suggests that with five SSR primer pairs, the majority of the Malus holdings could be assigned a unique fingerprint identity. The average direct count heterozygosity over all loci was 0.620, ranging in value from 0.293 to 0.871 over individual loci. These heterozygosity counts will be compared with a survey of naturally occurring M. sieversii to determine whether current repository holdings are representative of the overall levels of diversity occurring in Malus. Information generated with this study, coupled with passport and horticultural data will inform curatorial decisions regarding deaccessioning of duplicate holdings and plans for future germplasm collections.
Cryopreservation of Embryonic Axes and Axillary Buds of `Pineapple' Sweet Orange [Citrus sinensis (L.) Osb.] Encapsulated in Alginate Gel
Authors: Santos Izulme R. , Stushnoff Cecil
Published: February 2019

Economically, citrus is the second most-important fruit crop grown worldwide; thus germplasm conservation of commercial cultivars, as well as of wild relatives, is essential. Presently, citrus germplasm has been conserved mainly in field genebanks. This approach is helpful; however, it is costly, exposes germplasm to climatic and biological hazards, and is not a long-term conservation system. Cryopreservation (conservation in liquid nitrogen, at –150°C to –196°C) is a technique that can ensure long-term storage of plant material. Attempts to cryopreserve citrus are restricted to a few reports, but the results obtained are encouraging. The basic purpose of this study is to define cryopreservation protocols for embryo axes and axillary buds of `Pineapple' sweet orange using the encapsulation-dehydration method. Embryo axes encapsualted in Na-alginate beads, precultured with high levels of sucrose and dehydrated over silica gel before freezing in liquid nitrogen had 60% survival. No survival was obtained for buds treated the same way, however buds isolated from plants acclimated at 0°C over a 30-day period survived exposure to –20°C when slow cooled at 2°C/hour. Additional experiments will combine cold acclimation, slow cooling and pre-treatment with sugars and other chemical compounds as an attempt to enhance cold hardiness of axillary buds and obtain survival after freezing in liquid nitrogen. Different approaches will be used to increase embryo axes survival rates.
Purification and Characterization of a Polygalacturonase-inhibiting Protein from Grapefruit Flavedo
Authors: McCollum T. Gregory , Doostdar Hamed , Bausher M. , Mayer Richard T. , McDonald Roy E.
Published: February 2019

Polygalacturonase-inhibiting proteins (PGIPs) are believed to be one component of plants inherent defense mechanisms against fungal pathogens. We have purified a PGIP from mature grapefruit (Citrus paradisi cv. Marsh) flavedo using ammonium sulfate precipitation, preparative isoelectric focusing and ion exchange chromatography. Two peaks of PGIP activity were separated by isoelectric focusing, one at pH 6–7 and one at pH 9–10. The basic protein was more abundant than the neutral protein and was selected for further purification. The basic protein binds to S Sepharose at pH 6.1 and has an apparent Mr of ≈43,000 based on SDS-PAGE analysis. The protein is glycosylated as revealed by binding to ConA sepharose and is serologically similar to PGIPs from bean hypocotyl and pear fruit. Two dimensional PAGE analysis revealed the presence of two bands of similar Mr but with slightly different pIs (≈9.0–9.5). The N-terminal amino acid sequence of grapefruit PGIP shows high homology with PGIPs from fruit of other species and with a cDNA clone of PGIP that was isolated from a Citrus sinensis cv. Hamlin expression library. Grapefruit PGIP inhibits polygalacturonases from Aspergillus niger, and the citrus pathogen Penicillium italicum. We are interested in the role of PGIP in resistance of citrus fruit to postharvest decay fungi.
Growth of Turfgrasses under Different Levels of Shading
Authors: Liu Guofan , Kobayashi Kent D.
Published: February 2019

Turfgrass is grown under a wide range of environmental conditions, especially light conditions. In residential and commercial applications, selecting the appropriate turfgrass depends, in part, upon its performance under differing light conditions. This study was conducted to determine the growth habits of four turfgrasses under different shade treatments. `Common Bermuda', `Tif dwarf Bermuda', `Seashore Paspalum', and `Z-3' were grown outdoors in pots. `Z-3' is an attractive new variety of turfgrass for residential lawns. Benches were covered with shade cloth to provide different shade conditions (0%, 30%, and 50% shading). Clippings were taken every 2 weeks and dried to determine growth. Turfgrass growth under the three shade treatments were significantly different. In the 0% and 30% shade treatments, `Common Bermuda' and `Seashore Paspalum' had similar growth with their dry weights being greater than that of `Tif dwarf Bermuda' and `Z-3'. Under 50% shade, `Seashore Paspalum' grew significantly greater than the other turfgrasses. `Common Bermuda' grew significantly less under 50% shade than under 0% and 30% shade. `Common Bermuda' does well on golf courses because of its fast growth and attractiveness. With its vigorous growth and shade tolerance, `Seashore Paspalum' can be used for residential lawns. `Z-3' turfgrass, a relatively new variety for residential lawns, shows slow growth but is desirable because of its tolerance to different shade conditions.
Macroand Micronutrient Levels Associated with Nitrogen and Sulfur Applications to `Freedom Red' Poinsettia
Authors: Conley M. Elizabeth , Paparozzi Ellen T.
Published: February 2019

In order to understand the effects of reduced nitrogen and sulfur on overall poinsettia plant growth and development, experiments were run to determine the relationship, if any, between nitrogen and sulfur applied and other macroand micronutrients. Cuttings of `Freedom Red' (Euphorbia pulcherrima Willd. ex Klotzsch) were grown vegetatively in a peat:perlite:vermiculite mix during the fall and spring. Three levels of sulfur (0, 12.5, 25 ppm) were applied in combination with four levels of nitrogen (50, 100, 200, 275 ppm). The experimental design was a randomized complete block. Leaf samples were analyzed using LECO for nitrogen and ICP-ES for sulfur. X-ray fluorescence was used to determine trends in the nutrient concentration of other macronutrients and micronutrients. Nutrient analyses indicated that all nutrients were present in sufficient quantities. Leaf concentrations of nitrogen, sulfur, potassium, and copper were distinctly higher in spring and fall, while phosphorus, calcium, magnesium, and iron concentrations were higher in fall. The typically subtle effects of sulfur were most obvious in magnesium and calcium leaf concentrations. Phosphorus and calcium concentrations increased at lower levels of applied nitrogen. Concentrations of boron, copper, and manganese also increased strikingly at lower levels of applied nitrogen. Apparently when levels of nitrogen less than 200 ppm are applied, micronutrient uptake increases, suggesting the potential of either luxury consumption or possible toxic effects if too little nitrogen is supplied.
Effects of Irrigation Nonuniformity on Nitrogen and Water Use Efficiencies in Shallow-rooted Vegetable Cropping Systems
Authors: Sanden B. , Wu L. , Mitchell J.P. , Pan L. , Strohman R.
Published: February 2019

This research tests the hypothesis that decreasing lateral spacing from 45 to 35 feet in solid-set sprinkler systems increases the uniformity of irrigation water distribution and improves water and N fertilizer use efficiencies. Three different spacings between sprinkler laterals (35', 40', and 45') were set up in three blocks in a 60-acre commercial carrot field in Western Kern County in California's San Joaquin Valley. Determinations of irrigation water distribution uniformity, yields, crop water use, plant growth, and nitrate leaching were made. Mean sprinkler distribution uniformities (DU) were found to be 80.6%, 78.1%, and 86% for the 35-, 40-, and 45-ft spacings, respectively. Total carrot yield and quality did not differ significantly among the three spacings, corroborating the finding that irrigation uniformities were similar among the treatments. Although the three lateral spacings evaluated in this initial experiment did not result in major differences in irrigation uniformity, total yields, or quality, the findings of this initial stage of our research are significant. They point to the need for new assessments of currently used protocols for evaluating sprinkler irrigation management of water and nitrogen fertilizer if they can be confirmed by repeated trials in coming years.
Understanding the Role of Cytokinins in Tissue Proliferation of Rhododendron `Montego'
Authors: Mercure Eric W. , Auer Carol A. , Brand Mark H.
Published: February 2019

Tissue proliferation (TP) is characterized primarily by the formation of galls or tumors at the crown of container-grown rhododendrons propagated in vitro. However, TP of Rhododendron `Montego' is observed initially in in vitro shoot cultures and it is characterized by the formation of multiple shoots with small leaves and nodal tumors. The formation of shoots in `Montego' TP (TP+) shoot cultures occurs without the presence of exogenous cytokinin in the medium, unlike normal `Montego' (TP–) shoot cultures, which require cytokinin for shoot growth. Structural studies have shown that tumors are composed of many adventitious buds and parenchyma cells, suggesting that TP is a result of abnormal cytokinin regulation that is controlling tumor and shoot formation. Two approaches are being used to determine if differences in cytokinin concentration and/or metabolism exist between TP+ and TP– shoot cultures. In the first approach, shoot cultures are grown in vitro for 1 week in the presence of tritiated isopentenyladenine (iP). Cytokinin uptake and metabolism are analyzed using HPLC and other analytical methods. Experiments suggest that extensive degradation and N-glucoside conjugation occur in TP+ and TP– shoots, resulting in the removal of most of the exogenous iP. In the second approach, the levels of endogenous cytokinins such as iP, isopentenyladenosine, zeatin, and zeatin riboside, are being measured in TP+ tumors and shoots and in TP– shoots by an ELISA method.
Effects of Vesicular–Arbuscular Mycorrhizal Fungi on Rooting and Growth of Two Woody Ornamentals
Authors: Trépanier Martin , Rioux Jacques-André
Published: February 2019

A commercial inoculum of Glomus intraradices Schenk and Smith, a vesicular–arbuscular mycorrhizal fungus, has been used with the objective of studying its effects on rooting and on subsequent growth of two woody ornamental plants (Juniperus Sabina `Blue Danube' and Cornus sericea `Coloradensis'). This inoculum, called Mycorise™, is produced by Premier Peat Co. (Rivière-du-Loup, Québec, Canada) and it contains one propagule/g of Glomus intraradices. The cuttings's rooting media was mixed in order to contain 0%, 10%, 20%, 40%, or 80% of inoculum. Hardwood cuttings have been inserted in 65-ml cells and put under a mist until good rooting. For both species used, presence of inoculum in rooting media has not given significant effects during the rooting stage of cuttings, but has given some during the following stage of growth in 6-L containers. The growth of young mycorrhized plants of Juniperus was up to 50% greater than the control after the first season of growth. The young plants of Cornus have only showed a tendency to have a higher growth. Moreover, several mineral elements (N, P, Ca, Mn, Zn) were present at higher concentrations on mycorrhized plants. For roots colonization by the fungus and growth results, the inoculum proportion of the rooting media the most appropriate for Juniperus Sabina `Blue Danube', a slow-rooting species, was 40%, and the most appropriate for Cornus sericea `Coloradensis', a quick-rooting species, was 20%.
Rooting of Maple Cuttings as Influenced by IBA Treatment
Authors: Khatamian Houchang , Pair John C.
Published: February 2019

Softwood cuttings of Acer saccharum `Commemoration', a Caddo maple selection (90-7185), and Acer truncatum were collected on 12 July 1996 from specimen trees at the Wichita Hort. Res. Center. Ten uniform cuttings of 14to 19cm-long containing four to five leaves were dipped for 10 sec in 0, 5000, 10,000, 15,000, or 20,000 ppm IBA solution and Hormodin™ #2. Cuttings were rooted in a mix of 30% Canadian sphagnum peat and 70% perlite (v/v) and placed in a greenhouse located at Kansas State Univ. The greenhouse was equipped with a fog generator (Humidifan, turbo XE 1000) that was operated for 12 hr/day from 12 July to 5 Oct. 1996. After 12 weeks, cuttings were evaluated for rooting quality and percent using a visual rating scale of 1–5. `Commemoration' rooted with all IBA treatments. The control treatment resulted in a 100% rooting, whereas the rooting with 5000 or 10,000 ppm IBA and or Hormodin™ #2 was 90%. Caddo maple (90-7185) rooted at 89% with control treatment, followed by 78% and 67% with 10,000 ppm IBA and Hormodin™ #2, respectively. As reported previously, none of the cuttings of this maple, collected on 24 May 1995, had rooted, regardless of hormone treatment. The best rooting for Acer xtruncatum was 90% with 5000 ppm IBA and 80% with control and Hormodin™ #2, respectively.
Inheritance of Low-temperature-induced Cold Acclimation Response in Blueberry
Authors: Arora Rajeev , Rowland Lisa J. , Panta Ganesh R. , Lim Chon-Chong , Lehman Jeffrey S. , Vorsa Nicholi
Published: February 2019

Mode of inheritance of cold hardiness (CH) in woody perennials is not wellunderstood. This study was undertaken to determine the mode of inheritance and gene action of CH in blueberry (Vaccinium section Cyanococcus). Two testcross populations (segregating for CH) derived from interspecific hybrids of V. darrowi (drw) × V. caesariense (csr) were used. Plants were cold-acclimated by a 4-week exposure to 4°C. Bud CH (LT50) was defined as the temperature causing 50% injury (visual) when subjected to controlled freeze–thaw. Results show that the drw and csr parents had an LT50 of –13° and –20°C, respectively. The F1 population exhibited mean LT50 of –14.7°C. The csr and drw testcross populations had a mean LT50 of –18° (39 individuals) and –14°C (33 individuals), respectively. Individuals of each population were distributed between parental values with center of distribution skewed toward the testcross parent. Since individuals having LT50s as same as the recurrent parents were present in each population of only 33–39 plants, data suggest that CH is determined by relatively few genes. To determine gene action, the estimates for various genetic parameters (calculated from joint scaling test) were used in generation means analysis to test various models. Results indicate that CH in blueberry can be best explained by simple-additive dominance model, whereas models including epistatic components did not satisfactorily explain the data.
Inheritance of Resistance to Anthracnose Caused by Colletotrichum coccodes in Tomato (Lycopersicon esculentum)
Authors: Stommel John R. , Haynes Kathleen G.
Published: February 2019

Anthracnose, caused by Colletotrichum coccodes, is a serious ripe tomato fruit rot disease. Genetic resistance to anthracnose is not available in commercial tomato cultivars, but has been reported in small-fruited Plant Introductions (P.I.), and with lesser intensity in a number of breeding lines. Transfer of high levels of resistance from these breeding lines or P.I.s to elite materials has proven difficult. Inheritance of resistance has been described as complex with at least six loci influencing resistance reactions. Segregating populations originating from a cross between a susceptible tomato breeding line and a large-fruited breeding line (88B147) with resistance derived from Lycopersicon esculentum var. cerasiforme P.I. 272636, were evaluated for anthracnose resistance. Analysis of anthracnose resistance in puncture-inoculated fruit indicated small, but significant, additive genetic effects for resistance. Additional populations were developed from crosses of a susceptible inbred processing tomato cultivar with: 1) the resistant P.I. 272636, 2) an unadapted small-fruited resistant line developed from P.I. 272636, and 3) the large-fruited breeding line 88B147, also with resistance derived from P.I. 272636. Small additive effects identified in large-fruited material, in comparison to the resistant P.I., suggests that resistance loci have been lost during germplasm development. This is consistent with the relatively larger lesions observed in large-fruited lines derived from P.I. 272636. Positive correlations were noted between small fruit size and high levels of anthracnose resistance. Identification of molecular markers linked to resistance genes in the respective populations will be discussed.
Evaluation of Resistance to Bacterial Wilt and Phytophthora Blight in Peppers (Capsicum spp.) Collected in Ghana and Sri Lanka
Authors: Matsunaga H. , Sato T. , Monma S.
Published: February 2019

Thirty-one Capsicum accessions collected in Ghana and 20 Capsicum accessions introduced from Sri Lanka were evaluated for resistance to bacterial wilt and to Phytophthora blight. In the evaluation of resistance to bacterial wilt, 12 seedlings per accessions were transplanted to the infected field with Pseudomonas solanacearum. Subsequently, an inoculum suspension was poured into the soil at the base of each plant with root wounding. Disease severity of each plant was evaluated using a symptom index of 0 (no symptoms) to 4 (death) scale at 10 weeks after inoculation. In the evaluation of resistance to Phytophthora blight, 20 seedlings per accession were transplanted into a bed, the soil temperature of which was maintained at 28°C after root-dipping inoculation. Disease severity of each plant was evaluated using a symptom index of 0 (no symptoms) to 2 (death) scale at 2 weeks after inoculation. To bacterial wilt, two Ghanaian accessions and 10 Sri Lankan accessions had no symptoms and nine Ghanaian accessions and six Sri Lankan accessions showed some wilted plants, but their disease indices were less than 1. The accessions were regarded as resistant. To Phytophthora blight, two Ghanaian accessions and four Sri Lankan accessions were regarded as weakly resistant. Remaining accessions were regarded as susceptible. `GJ93/287' collected in Ghana and `Nil miris', `MI 1', `KA 11', introduced from Sri Lanka, were resistant to bacterial wilt and weakly resistant to Phytophthora blight.
An Ethylene-inducible Lipoxygenase Gene from Potato Leaves
Authors: Kolomiets Mikhailo V. , Gladon Richard J. , Hannapel David J.
Published: February 2019

Due to apparent participation of plant lipoxygenases (LOXs) in the biosynthetic pathways for jasmonic acid, methyl jasmonate, traumatin, and several C-6 volatile compounds, LOXs are believed to have a role in senescence, plant growth and development, and wound- and pathogen-induced defense responses. Multiple functions that are ascribed to this enzyme family are in accordance with the heterogeneity of LOX isozyme forms. It is possible that different LOX isoforms may be involved in different physiological processes. In our search for a gene that encodes a LOX isozyme form specifically involved in potato defense responses against pests and pathogens, we have screened an abscisic acid-induced potato leaf cDNA library, and we have isolated, sequenced, and characterized a cDNA clone that we have designated POTLX-3. The high sequence homology of our cDNA clone to other reported plant LOX genes provided evidence that POTLX-3 is a lipoxygenase. This cDNA clone represents a novel potato LOX gene in that it shares the least nucleotide and amino acid sequence homology to other isolated potato LOX genes. Northern analysis indicated that POTLX-3 transcripts did not accumulate in untreated potato leaves, but it was highly induced by treatment with physiological levels of ethylene. Northern analysis also was performed to study whether the POTLX-3 mRNA accumulation could be induced by other plant hormones that affect expression of the other plant LOX and defense-related genes. Treatment of potato leaves with methyl jasmonate, abscisic acid, gibberellic acid, auxin (NAA), and cytokinin (BA) did not induce POTLX-3 gene expression. Because the pattern of POTLX-3 gene expression is similar to that of pathogenesis-related (PR) proteins, especially the PR-1 and PR-5 groups, we suspect that POTLX-3 may be involved specifically in ethylene-induced defense responses against pathogens.
Sensitivity and Efficiency of Randomly Amplified Polymorphic DNA for Cultivar Identification in Sweetpotato
Authors: Zhang D.P. , Ghislain M. , Golmirzaie A. , Cervantes J.C.
Published: February 2019

Detecting inter- and intra-varietal variation is essential for the management of a plant germplasm bank. The sensitivity and efficiency of randomly amplified polymorphic DNA (RAPD) for cultivar identification and somaclonal mutation in sweetpotato were evaluated. RAPD demonstrated a highly significant inter-varietal variation. Every one of the 23 tested cultivars can be identified with a RAPD profile generated by a single primer. Suspected duplicates that are morphologically indistinguishable can be unambiguously verified with a combination of three decamers. No intra-varietal variation was found using RAPD. Clones of `Jewel' and `Beauregard' collected from different sources all have the same RAPD profiles. Moreover, with 150 markers, the transgenic `Chogoku' sweetpotato cannot be differentiated from its untransformed counterparts, even though the transgenic plant shows significant morphological changes. These results demonstrate that RAPD is a sensitive and efficient tool for identifying cultivar duplicates, but it is not efficient for detecting intra-clonal variation or somaclonal mutation in sweetpotato.
Evaluation of Popular Mountain Vegetables in Korea using Molecular Markers
Authors: Lim Hak-Tae
Published: February 2019

Five edible mountain vegetables (Saussurea sp., Aster tataricus, A. scaber, Synurus deltoides, Ligularia fischeri) were investigated on the basis of amplified DNA polymorphisms resulted from PCR–polymerase chain reaction analysis. The sampled plants consisted of 38 individuals in five taxa. Only 10 primers out of 62 [60 random (10-mer) primers, one 15-mer-M13 core sequence, and (GGAT)4 sequence] tested gave rise to polymorphisms in all of the tested plants, producing 176 DNA fragments amplified randomly and specifically. Intraspecific polymorphisms found in each taxa showed intra-variety constancy (31.1% to 40.9%) in the banding patterns of individual plants—Saussurea sp., 31.1%, 15 bands; Aster tataricus, 40.9%, 18 bands; A. scaber, 38.5%, 15 bands; Synurus deltoides, 34.7%, 17 bands; Ligularia fischeri, 38.9%; 22 bands, respectively. All five species were well-differentiated from each other at the 0.93 level of similarity index value. Genetic relationships among intraspecific and interspecific variations were closely related at the levels ranging from 0.62 to 0.99. Based on these results, our PCR analyses support the previous data derived from external morphology of the five edible mountain vegetables, but very low levels of intraspecific variations were detected in all of these taxa.
Sweet Pepper (Capsicum annuum) Transformation using Agrobacterium rhizogenes
Authors: Jayashankar S. , Bagga Suman , Phillips Gregory C.
Published: February 2019

In vitro genetic transformation of chile pepper, Capsicum annuum var. New Mexico 6-4, was achieved. Seeds of `New Mexico 6-4' were grown aseptically on Murashige and Skoog medium. Seedlings 22 days old were wounded on the hypocotyl region using a sterile hypodermic needle. A. rhizogenes strain K 599 harboring the plasmid p35S GUS Intron was inoculated on the wound site. Three days later the seedlings were transferred onto MS media with antibiotics (Cefotaxime, Carbenicillin, Amoxicillin, Clavulanic acid, and Kanamycin). New roots were seen to initiate from the wound site 15 to 20 days after inoculation. The roots were morphologically identified as “hairy roots.” Glucuronidase (Gus) assay performed 40 days after inoculation on randomly chosen roots that had grown into the selection medium, showed that 6/25 (24%) of the inoculated seedlings had roots that showed intense blue coloration. Presence of an intron makes it impossible for the bacteria to express the reporter gene. The seedlings that had transformed roots had a different morphology with wrinkled leaves and short internodes. The pattern of expression of the introduced gene varied greatly. Some positive tissues had the root tips alone being blue; a few had the vascular tissues and the root tips blue; and others had the vascular tissues, the surrounding parenchyma cells, root tips, and the root hairs turn very dark blue. The transformed roots did not need to grow into the selection media to be Gus positive. Isolated roots cultured on MS media supplemented with 0.2 mg/L IAA were maintained for 120 days and continued to express the reporter gene. Currently, methods to regenerate transformed shoots from roots are being tested. The “hairy root” transformation system in pepper could have application in the testing of root-expressible constructs for transgene expression assays.
Tree Growth in Potting Media Made with De-inked Paper Sludge
Authors: Tripepi Robert R. , George Mary W.
Published: February 2019

De-inked paper sludge from a newsprint mill was evaluated as a substitute for softwood bark in container media. Whips, 1.2 m tall, of `October Glory' red maple (Acer rubrum L.), European birch (Betula pendula Roth), and `Royalty' crabapple (Malus L.) were planted in 15-L plastic pots that contained potting media amended with 0%, 20%, 40%, 60%, 80%, or 90% paper sludge and 80%, 60%, 40%, 20%, 0%, or 0%, respectively, bark (by volume). All media contained 10% sand. After 22 weeks, plant heights, trunk diameters, and shoot dry weights were determined. Initial pH of media increased as the amount of paper sludge in the media increased, with the 90% sludge mix having pH 7.2. Paper sludge had a low initial CEC. Physical properties of all sludge-amended media were suitable for tree growth, but media containing 80% or more paper sludge shrank in volume by 10% to 12% by the end of the study. All maple and crabapple trees grown in all sludge-amended media grew as well as those in 80% bark (control mix). In fact, maple and crabapples trees in 40% sludge produced at least 10% and 36% more total shoot biomass, respectively, than trees in 80% bark. Although birch trees grown in 40% or 60% paper sludge grew as well as control plants, those grown in 80% or more sludge were at least 11% shorter and produced 24% less total shoot biomass (leaves, stems, and trunk dry weight) than control trees. These results demonstrated that de-inked paper sludge was a worthy substitute for up to 40% of the bark in a container medium for the three species tested.
Technology Transfer through the Use of Growers Clubs in Northwest Mexico
Authors: Grijalva-Contreras Raul Leonel , Lopez-Vilches Francisco , Salvador-Rivas Victor
Published: February 2019

The Growers Club provides a good alternative for technology transfer generation in experiment stations, universities, and other research institutions in Mexico. At this time, there are 10 Growers Clubs in northwest Mexico, mainly in Sonora and Sinaloa states. During 1996, in the agricultural area in Caborca, Sonora, the Grower Club “REME”-SOCOADA was formed with 10 members—all of them are willing to adopt new technologies. The main goal of this club is to improve the yield using the validation of new agricultural practices and evaluation of genetic material from different crops (annual crops, vegetables, fruit trees, and forage). We have six demonstration lots in different locations and we are planning to increase these to 11 and we will publish the results that we are going to get from these lots.
A Proficiency Testing Program for the Agricultural Laboratory Analysis Industry
Authors: Miller Robert O. , Newman Steven E. , Kotuby-Amacher Janice
Published: February 2019

The accuracy of soil and plant analytical results are occasionally called into question by laboratory clientele. Although laboratories generally conduct internal quality assurance procedures, there are few external performance testing programs for the industry. In 1994, a proficiency testing program was initiated for soil and plant samples for agricultural laboratories in the western United States to provide an external quality control for the lab industry. The program involves the quarterly exchange of soil and plant samples on which soil salinity, soil fertility, and plant nutrition analyses are conducted. One hundred laboratories are annually enrolled in the program from 24 states and Canadian provinces. Results of 3 years of the program indicate soil nitrate, soil pH, extractable potassium, soil and organic matter are reproducible within 10% between laboratories. Soil-extractable phosphorus (by five methods), soil-extractable boron, and soluble chloride were only reproducible within 15% to 20% between laboratories. Plant nitrogen and phosphorus results were consistent across samples, laboratories, and methods. Variability in plant nitrate increased with decreasing tissue concentrations. Overall accuracy and precision of reported results, based on the use of NIST certified reference botanical samples, were excellent for N, P, K, Ca, and Cu. Generally, for any given analysis, the results of ≈10% of the laboratories exceed two standard deviations from the mean. Overall, significant improvement was noted in the laboratory industry proficiency through the course of the program.
Biosynthesis of α-Farnesene in Apple Fruit
Authors: Rupasinghe H.P.V. , Paliyath G. , Murr D.P.
Published: February 2019

α-Farnesene is an acyclic sesquiterpene hydrocarbon that is a constituent of the surface wax of apples (Malus domestica Borkh.). Although, oxidation products of α-farnesene have been implicated in the development of the physiological disorder superficial scald in apple, the mechanism of α-farnesene biosynthesis has not been studied in detail. We are currently investigating α-farnesene biosynthesis in relation to superficial scald development in apples. Radiolabelled feeding experiments using isolated tissue segments indicated that α-farnesene is derived from trans,trans-farnesyl pyrophosphate (FPP), mainly in the skin rather than cortex. Among the other labeled products detected, farnesol level was over a hundred-fold higher compared to α-farnesene. However, [1-3H] trans,trans-Farnesol was not incorporated into α-farnesene. Feeding radiolabelled FPP to skin tissue segments of scald-developing and normal apples showed differential incorporation of radiolabel into various products. Though the incorporation into α-farnesene was nearly the same, there was higher levels of incorporation into farnesyl esters in normal apples. As well, the levels of radiolabelled in the farnesol fraction was three times higher in scald-developing regions. These results indicate that there are potential difference in the biosynthesis and metabolism of farnesyl components between scald-developing and normal apples. In studies using cell-free extracts, farnesol formation was observed from labeled FPP and was two-fold higher in crude membrane extract compared to crude cytosol. Our results indicate that α-farnesene formation in apple fruit tissue is through FPP and is possibly catalyzed by a single sesquiterpene synthase enzyme. Purification and characterization of this enzyme are in progress.
Reducing the Risk of Superficial Injury in `Golden Delicious' Apples Caused by Postharvest Application of CaCl2 Solutions
Authors: Saftner Robert A. , Conway William S. , Sams Carl E.
Published: February 2019

`Golden Delicious' apples were pressure-infiltrated (34 kPa) at harvest with 0, 20, 35, or 50 g·L–1 solutions of CaCl2 followed without and with a water rinse, a wax or shellac emulsion treatment, or a shrink-wrap packaging, and stored at 0°C. The CaCl2 treatments delayed senescent breakdown, but also caused superficial injury to the fruit. A water rinse in combination with a wax- or shellac-based coating or shrink wrap packaging reduced the appearance of superficial injury in fruit treated with 35 or 50 g·L–1 solutions of CaCl2 and eliminated it in fruit treated with a 20 g·L–1 solution of CaCl2. While reducing the risk of calcium-related injury to the fruit, the coating and film treatments maintained the beneficial effects of calcium on apples and reduced weight loss of the fruit during cold storage.