bluuebunny/crossref_metadata_2025 huggingface dataset:
070 Non-autonomous Maize Transposable Element, Dissociation (Ds) Transposed in Carrot (Daucus carota L.)
Authors: Ipek Ahmet , Simon Philipp W.
Published: February 2019

Maize transposable elements, Activator (Ac) and Ds transformed into several heterologous plant species for transposon tagging of genes. Several genes in Arabidopsis, flax, petunia, tobacco, and tomato have been tagged and cloned by using Ac and Ds. We have double transformed carrot lines, B493 and B7262 with stabilized autonomous Ac and non-autonomous Ds element to develop a two-element based transposon tagging system. PCR and Southern hybridization indicated that Ds element transposed from T-DNA in calli, somatic embryos and transgenic plants. The insertion of Ds element into new sites in carrot genome after excision verified by GUS assay, Southern hybridization and inverse-PCR. Currently, the behavior of non-autonomous Ds element is being studied. Ds induced mutation will be screened in transgenic plants. These initial results demonstrate that the Ac/Ds-based transposon tagging system may work in carrot.
080 Postharvest Longevity Analysis of Advance Generations in Antirrhinum majus L.
Authors: Martin William J. , Stimart Dennis P.
Published: February 2019

Cut flowers of Antirrhinum majus L. (snapdragon) P1, P2, F1, F3, and F2 × F2 plants were harvested after the first five flowers were open and were evaluated for postharvest longevity to further evaluate genes conditioning postharvest longevity. F3 progeny evaluated were derived by selfing F2 selections of long keeping, mid-range, and short keeping types. F2 × F2 progeny evaluated were derived from crosses within and between postharvest longevity categories. Populations for evaluation were grown in the greenhouse in winter 1998-1999 in a randomized complete-block design according to standard forcing procedures. Thirty plants of each genotype were held in the laboratory in deionized water under continuous fluorescent lighting at 22 °C for postharvest assessment. The end of postharvest life was defined as 50% of the flowers drying, browning, or wilting. Data will be presented on postharvest longevity and allelic relationships within populations.
083 Modification of Plant Architecture in Chrysanthemum: Reduction of Height and Increase of Branch Angle through Ectopic Expression of a Phytochrome B1 Gene
Authors: Zheng Zhi-Liang , Jang Jyan-Chyun , Metzger James D. , Yang Zhenbiao
Published: February 2019

Plant architecture is a major consideration during the commercial production of chrysanthemum (Dendranthema grandiflora Tzvelev). We have addressed this problem through a biotechnological approach: genetic engineering of chrysanthemum cv. Iridon plants that ectopically expressed a tobacco phytochrome B1 gene under the control of the CaMV 35S promoter. The transgenic plants were shorter, greener in leaves, and had larger branch angles than wild-type (WT) plants. Transgenic plants also phenocopied WT plants grown under light condition depleted of far-red wavelengths. Furthermore, the reduction of growth by the expressed PHY-B1 transgene did not directly involve gibberellins. The commercial application of this biotechnology could provide an economic alternative to the use of chemical growth regulators, and thus reduce the production cost.
086 Preservation and DNA Fingerprinting Historic Prunus × yedoensis Germplasm from the Tidal Basin in Washington, D.C.
Authors: Pooler Margaret R. , Dix Ruth L.
Published: February 2019

The historic Japanese flowering cherry trees planted around the Tidal Basin in Washington, D.C., were given to the United States in 1912 as a gift from Japan, and have become a popular tourist attraction. Unfortunately, only a small portion of the original trees remain, and these trees are in various states of decline due to old age and stress. In cooperation with the National Park Service, we have propagated from cuttings nine trees that are known to be original and 10 trees that are thought to be original. DNA from these and other P. × yedoensis were compared using RAPD markers. Twenty-one 10-nucleotide primers yielded 80 repeatable bands that were used to assess genetic distance among the accessions. Twenty of these bands were monomorphic across all 28 accessions tested, so were not informative. The frequency of the remaining 60 bands varied from 0.04 to 0.96, with an average frequency of 0.58. Thirteen of the accessions, including six of the nine that are known to be original germplasm, were identical at all loci tested. Other accessions that are thought to be original trees were similar, with similarity values of 0.93 to 0.99. The most genetically dissimilar trees were P. × yedoensis accessions from our collection that were collected as seed in Japan. Accessions obtained from commercial nurseries including `Afterglow', `Akebono” and Yoshino were also dissimilar to the Tidal Basin trees. This study indicates that most of the older trees planted around the Tidal Basin are genetically very similar, but that variability in P. × yedoensis exists, especially in accessions collected as seed from Japan.
088 Microprojectile Bombardment-mediated Transformation of Rhododendron `Catawbiense Album' L.
Authors: Knapp Jane E. , Brand Mark H.
Published: February 2019

Horticultural improvements in Rhododendron require long periods of time to produce flowering plants by traditional breeding methods. In addition, new trait development by conventional genetics is limited to existing germplasm. Genetic engineering approaches to horticultural improvement offer the possibility for introduction of new traits using foreign DNA from any source. To this end, we have developed a system for the genetic transformation of Rhododendron based on microprojectile bombardment. Leaves from in vitro-grown plantlets of R. `Catawbiense Album' L. were bombarded with the marker genes uidA (GUS) in combination with nptII or hph. Two days post-bombardment, explants were transferred to shoot iniation medium containing either 50 mg/L kanamycin or 2.5 mg/L hygromycin. After 4 weeks, proliferating tissues were transferred to media containing increased levels of selective agent (100 mg/L kanamycin or 5 mg/L hygromycin, respectively). Shoots that regenerated were then excised from necrotic tissues and transferred to shoot proliferation medium containing the high level of selective agent. PCR analysis of putative transformants revealed the presence of the transgenes. Southern blot hybridization confirmed stable transgene integration. Histochemical GUS assays of transformed tissues indicated uniform expression throughout the transgenic plant. With the development of an efficient transformation system, the introduction of genes to confer useful horticultural traits becomes feasible.
090 Pollen Viability in Inland Saltgrass
Authors: Reid Scott , Harrington Judy , Hughes Harrison
Published: February 2019

Distichlis spicata var. stricta (Torrey) Beetle is a native grass that tolerates salt, high pH, and some heavy metals. It has been proposed for use in several challenging environments, including mine spoils and salt-impacted areas of golf courses. But, its widespread use has been hindered by several factors, one of which is poor seed set. Because chromosome numbers are variable and some genotypes are aneuploids, there was concern that pollen viability in some genotypes was low. Pollen from several genotypes failed to germinate in vitro on four artificial media prepared with various levels of osmoticum. However, hand pollination in vivo resulted in profuse pollen germination for all genotypes tested. Germination on pollinated stigmas was observed at intervals beginning 2 h after pollination with a fluorescence microscope using aniline blue and acridine orange stains and in bright field using toluidine-O stain. Very young stigmas seemed unreceptive and, while pollen would germinate, the pollen tubes would not grow down through the style. On receptive stigmas, many pollen tubes grew down toward the egg and some reached it within 24 h. There was no evidence of impaired fertility. Aniline blue was the best method for observing pollen tube growth through the style, although toluidine-O was adequate for observing germination on the stigmatic surface.
093 Putative Sources in Strawberry for Resistance to Bacterial Angular Leafspot
Authors: Maas J.L. , Gouin-Behe C. , Hartung J.S , Hokanson S.C.
Published: February 2019

Bacterial angular leafspot disease (BALD) of strawberry, caused by Xanthomonas fragariae Kennedy & King, has dramatically affected commercial fruit and plant production throughout the world. Leaf lesions may kill leaves, while lesions on sepals make fruit unmarketable. The bacterium can kill stolon-tip plantlets that are being rooted for transplanting. Since plants become systemically infected, there is no adequate chemical control for BALD under conditions that favor development and spread of the disease. Strawberry is the only host and no cultivars or advanced selections have proven resistant to this disease. We screened 23 Fragaria ×ananassa, 13 F. chiloensis, 56 F. virginiana, and 2 F. vesca genotypes for resistance to two pathogenic isolates of X. fragariae (ATCC-33239, the original strain from Minnesota and Xf-3 from North Carolina). Leaves were inoculated by forcing bacterial suspensions into leaves under pressure with a syringe barrel and plunger. Plants were incubated in a moisture chamber for 3 days, followed by 1 week under mist and then placed on a greenhouse bench. Experiments were done twice for obviously susceptible reactions and three and four times for questionable and resistant reactions, respectively. Only two genotypes were found to show a resistant reaction: 80-4-38 (`Earliglow' (F. virginiana clone SG-26 from Georgia) and F. virginiana clone SG-89 (=Luby MS 7-7 from Minnesota). Each of these genotypes exhibited typical hypersensitive responses by walling-off inoculation areas. All other genotypes exhibited typical BALD symptoms 5 weeks after inoculation with both isolates.
107 Silver Thiosulfate (STS) Alone and in Combination with Gibberellic Acid (GA3) in the Forcing Solution Influences Budbreak and Shoot Elongation of Dormant Woody Plant Species
Authors: Hamooh Bahget T. , Read Paul E.
Published: February 2019

Research was conducted to further modify the forcing solution system in order to expedite the propagation of woody plants, such as Spiraea canescens, Lonicera maakii, and Cornus alba. Time of immersion in solutions containing 5 mM silver thiosulfate (STS) was compared with the basic forcing solution reported by Yang and Read (1989), a solution containing 200 mg 8-hydroxyquinoline citrate per liter and 2% sucrose. Other treatments employed were gibberellic acid (GA3) 50 mg per liter for 24 h and a combination of STS and GA3 for the same amount of time. Increasing the time in STS solution up to 24 h led to higher percent budbreak and shorter time to budbreak for all the three species examined. The combination of STS and GA3 was the most effective treatment overall in reducing time of budbreak and increasing percent of budbreak. All STS treatments studied showed similar responses in shoot elongation. However, treatments with GA3 alone, and in combination with STS showed more than a doubling in shoot length compared to all STS treatments studied and the control. Implications based on SEM observations will be presented.
110 Callogenesis and Organogenesis of the Apple Rootstock (Malus prunifolia) cv. Marubakaido under Different Aluminum Concentrations and Different Locations of Explants in the Leaf
Authors: de M. Dantas Adriana C. , Nezi Adriano N. , de L. Fortes Gerson R.
Published: February 2019

Three different leaf segments (apical, basal, and middle) were treated in combination with aluminum at 0, 5, 10, 15 and 20 mg·L-1. Three kinds of leaf segments were inoculated in flasks in 12 replicates, with the adaxial surface touching the medium composed by basic macro- and micronutrient and MS vitamins added to 2,4-D (1.0 mg·L-1); BAP (5.0 mg·L-1); sucrose (30.0 g·L-1); myo-inositol (100.0 mg·L-1) and agar (6.0 g·L-1). The pH was adjusted to 4.0 before autoclaving. After inoculation, the explants were incubated in a dark growth room for 21 days and then, placed during 80 days, at 25 ± 2 °C, 16-h photoperiod provided by white fluorescent lamps under 19 μE·m-2·s-1 radiation. At the end of this period, the explants were evaluated. It was observed that basal leaf explants provided greener callus and that the heavier ones came from the middle leaf explants. Absence of Al or high Al concentrations favored the number of adventitious buds, whereas intermediate concentrations inhibited them. The absence of Al favored basal explants to form adventitious shoots, while lower concentrations favored apical and basal segments. High Al concentration appear to stimulate adventitious shoots in the basal and middle explants. Although it was evident that callus intensities were lower in higher Al concentration, Al is not so harmful to callogenesis and organogenesis.
117 An In Vitro Regeneration System for Basil (Ocimum basilicum L.)
Authors: Phippen Winthrop B. , Simon James E.
Published: February 2019

A plant regeneration protocol was successfully developed for basil (O. basilicum L.). Explants from 1-month-old seedlings yielded the highest frequency of regeneration of shoots (37%) with an average number of 3.6 shoots per explant. Calli and shoot induction were initiated on Murashige and Skoog (MS) basal medium supplemented with thidiazuron (TDZ) (4 mg/L) for ≈30 days. Shoot induction and development was achieved by refreshing the induction medium once after 14 days. The most morphogenetically responsive explants were basal leaf explants from the first fully expanded true leafs of greenhouse-grown basil seedlings. Developing shoots were then rooted on MS media in the dark without TDZ. Within 20 days, rooted plantlets were transferred and acclimatized under greenhouse conditions where they developed normal morphological characteristics. This is the first report of a successful in vitro regeneration system for basil through primary callus. The establishment of a reliable regeneration procedure is critical when developing a transformation protocol for enhancing the production of basil for insect and disease resistance and improved essential oil constituents.
119 Rapid Somatic Embryogenesis and Plant Regeneration in American Ginseng (Panax quiquefolium L.)
Authors: Wang X. , Proctor J.T.A. , Raj S. Krishna , Saxena P.K.
Published: February 2019

Ginseng is a very valuable agricultural species grown for its root, which contains pharmacologically active constituents. One limiting factor for expansion of ginseng production is an efficient method for mass propagation. Currently, seeding is the principal method of propagating ginseng, but the embryo of ginseng seeds at harvest is immature. A stratification schedule consisting of a cool-warm-cool temperature treatment over 18-22 months is required for embryo development and seed germination. An alternative for the efficient production of ginseng is mass propagation through the use of in vitro culture techniques. The objective of this work was to develop a highly efficient system for regeneration of ginseng. The efficacy of three auxins, viz. 2,4-D, NAA and dicamba, were compared for the induction of somatic embryogenesis in American ginseng. Somatic embryos formed on ginseng cotyledonary, zygotic embryo, and shoot explants after 8 weeks of induction by the auxins. Significantly more somatic embryos were induced by culture of any of the ginseng explants on media supplemented with 5 μmol·L-1 2,4-D than any other auxin treatment. Histological and SEM studies confirmed that the regenerants were somatic embryos. Somatic embryos germinated and developed into normal plants in 3-6 months. The development of a regeneration system for ginseng using somatic embryogenesis is a necessary first step for mass propagation and the improvement of American ginseng.
123 The Potential Use of Spent Mushroom Compost as a Soil Amendment for Nursery Crop Production
Authors: Young Jay , Heuser Charles , Holcomb E.J.
Published: February 2019

The use of spent mushroom compost (SMC) as a media amendment for containerized greenhouse and nursery crop production is a promising alternative to disposal of this by-product of mushroom production. Fresh SMC is the compost that is removed from the mushroom house and used without further weathering. The objectives of this study include first, identification of key factors involved its successful use and second demonstration of the effective use of SMC by nurserymen. The plant material used includes both bedding plants and woody perennial species. Results demonstrate that the key factor in the use of SMC for plant production is high soluble salts. Leaching can reduce the high soluble salts. In addition, special consideration should be given to the reduction in potted media volume over time due to composting that continues after the material is removed from mushroom production. SMC as the sole growing media was not as effective as when SMC was amended with a commercial nursery growing mix. Several species were grown in 0%, 25%, 50%, 75%, and 100% mixtures of SMC and a commercial nursery mix. All species grew well in 50% SMC/50% nursery mix.
126 Nutrient Analysis of Organic Fertilizers for Greenhouse Vegetable Production
Authors: Anderson Robert G. , Hadad Robert
Published: February 2019

A segment of the greenhouse crop market would like to obtain vegetables and herbs that are certified organic. The technology for the use of biological controls for insects and diseases is well-developed and a significant part of greenhouse vegetable production. Organic fertilizers, however, have not been well-utilized in organic greenhouse vegetable production. Common organic fertilizers were analyzed for the levels of nutrients when mixed with water for use in greenhouse fertigation. Products derived from algae-Algamin (liquid) and Ohrstrom's Garden Maxicrop (powder), Bat Guano, and products derived from fish waste-GreenAll Fish Emulsion (liquid) and Mermaid's Fish Powder, demonstrated nutrient levels comparable to typical water-soluble fertilizers used for greenhouse plant production. Although the organic fertilizers could not be used as a concentrate for injector systems, readings from a conductivity meter were directly related to nitrate nitrogen levels and could be used for fertilizer management in the capillary mat subirrigation system used for plant production.
127 Growth of Impatiens `Accent Orange' in Substrates Containing Compost with Four Slow-release Fertilizer Concentrations
Authors: Klock-Moore Kimberly
Published: February 2019

The objective of this experiment was to compare the growth of impatiens `Accent Orange' in substrates containing compost made from biosolids and yard trimmings with four slow-release fertilizer application rates. Plugs of impatiens were transplanted into 400-ml pots filled with 100% compost as a stand-alone substrate or with 60%, 30%, or 0% compost combined with control substrate components. Six days after transplanting, all plants were top-dressed with 0.5, 1, 2, or 4 g of Nutricote 13N-5.7P-10.8K (type 180) per pot. Shoot dry mass increased as the percentage of compost in the substrate increased from 0% to 100%. Shoot dry mass also increased as the fertilizer application rate increased from 0.5 to 4 g per pot. Plants grown in 30% and 60% compost with 0.5 g of fertilizer were similar in size to plants grown in 0% compost with 4 g of fertilizer per pot. Plants grown in 100% compost at all of the fertilizer rates were larger than all other plants in this study.
128 Release of Zinc from Shredded Waste Tires Designed for Use as a Substrate Amendment
Authors: Dallman Amy , Taber H. , Evans M. , Shogren D.
Published: February 2019

Shredded rubber from automotive waste tires has been proposed as a potential component for use as a potting root substrate. One of the problems with using shredded rubber as a root substrate is that it releases potentially phytotoxic levels of Zn. Therefore, we were interested in washing the rubber particles with either distilled water, 0.1N HCl, or 0.05N DTPA before inclusion of the rubber in the potting mix. A coarse and a fine grade were used. Seventy-two percent (% w/w) of the particles in the coarse grade were within a particle size range of 2.8-6.3 mm, while only 52% of the particles in the fine grade were within this range. The ratio of extractant to shredded rubber was 2:1 (v/v). The soaking time varied from 1 to 96 hours with the extractant changed every 1, 2, 12, or 24 hours. For either particle size, the 0.1N HCl extractant removed 25 times more Zn than the water and 1.5 times more than the DTPA. With the 0.1N HCl extractant, three times more Zn was removed from the fine rubber as compared with the coarse material. Seventy-five percent of the Zn extracted was removed in the first hour of soaking and 92% removed within 72 hours.
137 Evaluating PARJIB, a Model of Vegetable Crop Performance in Response to Nutrient Supply
Authors: Reid J.B. , Renquist A.R. , Pearson A.J. , Stone P.J.
Published: February 2019

Economic and environmental concerns have increased the need for quantitative advice on fertilizer rates. In addition, it would aid researchers to be able to estimate the degree to which nutrient availability is affecting yield in a wide variety of field experiments. All of these needs can, in principle, be addressed using the new PARJIB model. PARJIB retains the functional simplicity of much earlier analytical models of crop responses to soil test values and fertiliser application rates. However, in a key departure from previous approaches, response to scaled nutrient supply indices is dictated by the potential yield adjusted for plant population and water stress. The version currently being evaluated simulates responses to supply of N, P, K and Mg, varying either singly or in combination. We have calibrated the model for sweet corn, carrots, and snap bean crops grown under temperate conditions in a wide range of soils. Simulated yields agreed well with observed values; the root mean square error was 8% to 13%, and regressions of observed against simulated yields passed through the origin with slopes that were not significantly different from 1. After calibration, the model predicted strong interactions between nutrient supply, plant population and water stress. PARJIB appears to have substantial potential to improve nutrient management for horticultural crops.
144 The Ripple Effect: Training Veteran Master Gardeners to Train Incoming Volunteers
Authors: VanDerZanden Ann Marie , Gredler Gail
Published: February 2019

Oregon State University Master Gardener volunteers are the backbone of home horticulture program delivery in Oregon. In 1997, more than 800 new Master Gardeners received between 48 and 66 hours of initial training at 17 sites throughout Oregon. A reduction in faculty available to train Master Gardeners and reduced travel budgets for existing faculty have made it difficult to effectively deliver training on a statewide basis. One solution to this problem is to train veteran Master Gardeners to assume some of the teaching duties for the initial training in their respective counties. In Sept. 1998, 45 veteran Master Gardeners attended a 2-day training seminar to learn to deliver two 3-hour training modules to Master Gardener trainees. Participants learned to use curriculum materials developed for training sessions on vegetable gardening and herbaceous ornamentals. Curriculum materials include annotated slide sets, handouts, suggested activities, entry/exit quizzes, and teaching evaluations for each module. Participants also received training on effective teaching strategies for the adult learner. Participants delivered the training in their respective counties during winter 1999 and returned an evaluation of the training experience. Benefits of this program included reduced training expense and teaching time for Extension faculty, increased volunteer commitment and participation in Master Gardener training, an advanced training opportunity for veteran Master Gardeners, availability of curriculum materials for future training, and improved retention of veteran Master Gardeners.
148 Incorporating Technology Across the Curriculum: GPS/GIS for Agricultural Sciences Education
Authors: Bates Rick
Published: February 2019

Global positioning system (GPS) and geographic information system (GIS) technologies are at the cutting edge of an emerging agricultural revolution called site-specific management. Anticipated benefits are both economic and environmental because in this system, herbicides, fertilizers and other inputs are placed only where needed in the precise amounts required. The opportunities for site-specific management of crops, soils, and pests are innumerable. However, most students of agriculture and land resource sciences have little, if any, experience with the GPS and GIS technologies that provide these new opportunities. Beginning in 1995, efforts were undertaken to integrate GPS/GIS technology into the College of Agriculture curriculum. The process began with GPS/GIS training workshops for local and regional faculty. Key faculty modified curriculum within several departmental options and produced instructional modules for 12 different agriculture science courses. Experiential learning opportunities were developed and in some classes, farmer practitioners of site-specific management participated with students in identifying management problems and solutions. Instructional modules and active learning exercises were formally evaluated as to their effects on enhanced student decisionmaking skills and competency in GPS/GIS applications. Recently the new course LRES 357 “GPS/GIS Applications” was added to the curriculum and work is underway to place this course on-line.
152 Festival of Color: An Extension Outreach Program
Authors: Steinegger Donald H.
Published: February 2019

The Festival of Color is the annual plant and landscape open house sponsored by the Univ. of Nebraska's Horticulture Dept. The festival is the culmination of many water-centered activities that have preceded the festival throughout the year. Last year's September event drew over 10,000 people to the UNL Agricultural Research and Development Center near Mead, Neb. The festival was created to increase the urban public's awareness and motivation regarding the best landscape management practices for developing environmentally compatible landscapes and reducing urban runoff of water and pesticides. The Festival of Color is an event for all ages. By including the activities for the entire family, the festival draws a large spectrum of the urban population. The festival has grown steadily from 850 visitors in 1993 to 10,000 in 1998. The festival will continue to include demonstrations and talks on selection, installation, and management of turf; irrigation equipment and management methods; pesticide selection and pest management alternatives; fertility management alternatives; low input landscaping with native and adapted species; composting; and more. At the Sixth Annual Festival of Color: 1) 42% of new attendees learned how to implement water conserving landscape techniques (66% of the previous attendees implemented water conserving landscape practices), 2) 30% of new attendees learned how to irrigate more efficiently (63% of previous attendees used water more efficiently), and 3) 29% of new attendees learned how to fertilize more efficiently (actual positive behavior change was higher than the proposed change reported by first time attendees), 4) 98% of new attendees learned how to choose plants based on site/location “Right Plant, Right Place” (86% of previous attendees have improved their plant selection skills by putting the right plant in the right place).
160 A Closed-capture Irrigation Effluent Apparatus for Large Nursery Containers
Authors: Bush Edward W. , Gray Ann L. , Wilson Paul W. , Owings Allen D.
Published: February 2019

A closed capture irrigation apparatus was designed and constructed for the purpose of monitoring irrigation effluent volume and nutrient analysis from 121-L redwood tree boxes. Measurements were taken monthly from Apr. 1997 to Oct. 1998. Tree boxes were filled with either a 3 pine bark: 1 sand: 1 peat or 3 pine bark: 1 soil media and planted with `Little Gem' magnolia [Magnolia grandiflora (L.) `Little Gem'] or Southern live oak (Quercus virginiana var. virginiana Mill.). In-line, pressure-compensated drip emitters provided irrigation water at the rate of 2 L/h. Daily irrigation volume ranged from 8 L in the fall and spring to 16 L during the summer months. The collection apparatus was constructed from 1-cm angle iron, neoprene rubber, a small drain assembly, and a 22-L plastic container. A square metal frame (43 × 43 cm) was supported by 31-cm legs and draped by a neoprene rubber mat with a drain assembly installed in the center. The drain was positioned into the plastic container creating a closed system to reduce effluent evaporation. The container capacity was adequate to store at least 24 h of collected effluent. This apparatus proved to be an efficient method of collecting irrigation effluent from large containers.
164 Mandatory and Elective Internships: Are They Different?
Authors: McConnell Dennis B. , Bradley Jennifer C. , Pennisi Svoboda V.
Published: February 2019

In 1975, the Environmental Horticulture Dept. initiated a work experience program. Students who work full time for an environmental firm of institution may register for ORH 4941 Practical Work Experience. Although ORH 4941 was not required, 241 students participated in the program during the 22 years when it was an elective course. In 1998, the departmental education committee changed the status of ORH 4941 from an elective to a required course. The objectives of this study were to determine if any differences have occurred since the status of the course has changed. The following were examined: 1) selected student characteristics (GPA, gender, age, etc.), 2) employing firms participating in the work experience program, and 3) required administrative procedures.
172 Changes in Quality and Maturity of Early Season Nectarines (cvs. Aurelio and Early May) during Maturation and Ripening
Authors: Luchsinger L.E. , Reginato G.H. , Miranda P.
Published: February 2019

The objectives of this study were to characterize the quality and maturity changes of nectarine (Prunus persica var. Nectarina) fruit cvs. Aurelio and Early May during maturation and ripening and to identify harvest maturity indices. After fruit set, 250 fruit of similar diameter and tree position were tagged to follow maturation and ripening on the tree. During commercial harvest, 48 fruit were ramdomly harvested every 2 to 3 days. Ethylene evolution rate (EER) at 20 °C, fresh weight, and peel ground and cover color (L*, a*, b*, C* and Hue value) were measured on all 48 fruit. Flesh color, firmness at several fruit points, soluble solids (SS), pH, titratable acidity (TA) and SS: TA ratio were measured only to 24 fruit, and the rest were held for up to 7 days at 20 °C as a ripening period to measure the same parameters mentioned above. Pearson correlation coefficients were determined between variables to explore possible harvest maturity indices. The most significant changes occurred in EER, fruit firmness, and peel ground color (a* and hue value). For `Aurelio' nectarines the highest correlations (P < 0.001) were obtained between logEER-tip firmness (r = -0.69), tip firmness-a* ground color (r = -0.66) and, tip firmness-hue ground color (r = -0.67). No important correlations (r > 0.60) were found for `Early May' nectarines. It was also found that fruit softening varies according to the point of measurement in the fruit depending on the cultivar.
184 The Influence of Trellising System and Cane Density on `Titan' Red Raspberries
Authors: Heuvel Justine Vanden , Sullivan J. Alan , Proctor John T.A.
Published: February 2019

The effect of three trellising systems (Hedgerow, V-Trellis, and Single-Sided Shift-trellis) and four cane densities were studied on Rubus ideaus L. cv. Titan red raspberries. Yield, cane growth, canopy microclimate, disease load, canopy light penetration, and fruit quality were examined. The treatments significantly affected yield and yield components. The V-trellis had a higher yield (+19%) and a larger fruiting framework than the hedgerow, while the shift-trellis had a lower yield than the hedgerow (-36%) and the V-trellis (-50%) due to a small fruiting framework. Path analysis indicated that interrelationships among yield components were significantly affected by trellising system. The shift-trellis was found to have lower quality berries than the other systems. These differences were related to light penetration into the different canopies. An optimum cane density was not found for any system. Yield potential per cane decreased as cane density increased; however yield per square meter increased as cane number increased. Berry quality decreased as cane density increased. Differing cane density did not affect canopy microclimate or disease load.
191 Structure and Development of Cultivated Grapevines in the Northeastern United States
Authors: Goffinet Martin C. , Welser Mary Jean , Lakso Alan N. , Pool Robert M.
Published: February 2019

Northeastern U.S. grape growers have become more knowledgeable about many aspects of grape production, including pruning and training, canopy management, nutritional recommendations, pest and disease management strategies, vineyard floor management, etc. Important to all these aspects is a firm understanding of vine structure and development. Yet, there is no current publication on vine growth and development that growers and researchers can consult to gain an understanding of the organs, tissues, and developmental processes that contribute to growth and production of quality vines in the northeastern U.S. climate. A concerted effort is underway to secure enough information on how vines are constructed, grow, and develop in the northeast so that a publication useful to a wide audience can be produced. Our objective is to consolidate information already on hand that can help explain the internal and external structures of grapevines that are pertinent to the needs of northeast growers, to add information that is lacking by collecting and examining vine parts, and to work toward integrating vine structure with vine physiology and viticultural practices. Over the past decade, organs of various native American, French hybrid, and vinifera varieties have been collected from vineyards at Cornell's experiment stations and from growers' vineyards in the Finger Lakes and Lake Erie regions. Much quantitative data on vine development have been collected and interpreted. Lab work has included dissections of organs, histological and microscopic examination, microphotography, and the production of interpretive diagrams and charts. A list of the subject matter and examples of visual materials will be presented.
199 Influence of Photoperiod, Temperature, and Growth Regulators on Growth and Flowering of Helichrysum and Brachycome
Authors: Phillips Jessica , Garner James M. , Armitage Allan M.
Published: February 2019

Five taxa of Helichrysum Mill. and Brachycome Cass. were recently evaluated for greenhouse production and amenity use. Preliminary studies on the influence of photoperiod, temperature, and growth regulators were conducted for H. bracteatum Vent., (syn Bracteantha bracteata) `Sunray' and `Matilda Yellow', H. apiculatum D.C, (syn Chrysocephalum apiculatum) `Golden Buttons' and Brachycome iberidifolia Benth. `Jumbo Mauve' and `Mauve Delight'. All taxa of Helichrysum were quantitative LD plants, flowering slightly more rapidly under night-break (2200-0200 HR) and extended day incandescent lighting, compared with 9-h short-day treatment. No influence of photoperiod occurred with cultivars of Brachycome. Constant temperature of 12, 20, or 28 °C were provided and all taxa demonstrated a linear decrease in flowering time as temperatures increased. The growth index (average of height and two measurements of width) was also influenced by temperature. Paclobutrazol and daminozide were applied at different concentrations and frequencies. Paclobutrazol was more effective than daminozide in both genera, and daminozide was ineffective in Brachycome.
202 Production of Cut Flowers from Field-grown Hydrangeas
Authors: Wolfe Dwight , Dunwell Winston
Published: February 2019

Cut flowers from field-grown hydrangeas are a potential alternative source of income for Kentucky growers. Early production is important to receive immediate returns of ones investment. In Spring 1998, a hydrangea cultivar trial was established at the Univ. of Kentucky Research and Education Center, Princeton. The planting consisted of 12 plants each of nine cultivars (`Annabelle', `Boskoop', `Pink Diamond', `Unique', `Kyushu', `Tardiva', `Pee Wee', `Alice', and `White Moth') allocated to 12 rows (blocks) in a randomized block design. Date of first bloom, number of inflorescence at first bloom, number of stems and their length were recorded. The cultivars `Unique', `Pink Diamond', and `Tardiva' yielded significantly more flowers with commercially desirable stem lengths (>45 cm) than did `Annabelle' and `Boskoop'. `Alice' and `White Moth' did not bloom.
216 Squash Pollination by Honey Bees vs. Native Pollinators in Maine
Authors: Merrick Laura C. , Drummond Frank , Stubbs Constance , Weber Rhonda
Published: February 2019

Managed and feral honey bee (Apis mellifera) colonies have declined dramatically in the past decade due largely to parasitic mites, pesticide contamination, and severe weather. Squash (Cucurbita spp.) is one of many agricultural crops whose production may be negatively effected by decline of these pollinators. A study was conducted on a set of nine farms in Maine to assess the relationship between bee abundance and fruit set of summer and winter squash. The organic and conventional farms targeted in the study included farms with and without the presence of honey bees. With winter squash, fields with more bees tended to exhibit higher fruit set. The average fruit set was slightly higher for farms with honey bees (42%) vs. those without (35%), but both types of farms were similar to that found in controlled hand pollinations (31% on average). In contrast, fruit set for summer squash averaged 95% to 96% for all farms, regardless of the relative abundance of censused bees. Bumble bees (Bombus spp.) were the most abundant wild bees found pollinating squash. Farms with honey bees on average had higher numbers of bees in squash flowers than farms without honey bees, although a difference in preference for floral sex type was detected for bee taxa. Honey bees were much more likely to be found in female flowers, while bumble bees were more abundant in male flowers. Significantly more native bees were found in squash flowers on farms without honey bee hives, although native bees were still present to some extent on farms that were dominated by Apis mellifera.
236 Breeding and Selection for Low-bearing Papaya in the Virgin Islands
Authors: Zimmerman T.W. , Kowalski J.A.
Published: February 2019

Demand for locally produced papaya fruit (Carica papaya) far outweighs the supply in the U.S. Virgin Islands. Due to the high incidence of papaya ringspot virus (PRSV), papayas are grown as an annual crop. The need exists in the Virgin Islands for papayas with early production to ensure a marketable crop before being devastated by PRSV. Breeding and selection has been ongoing for 5 years to develop papayas with tolerance to PRSV and fruit production starting at or less than 60 cm from the ground. The height at first fruit set, of 15 papaya cultivars recommended for the Virgin Islands, ranges from 58 cm to 253 cm. Generally, female plants started setting fruit lower on the stem than hermaphroditic plants. Through breeding and selection, three papaya lines have been developed that set the first fruit between 40 and 60 cm from the ground and exhibit tolerance to PRSV. These low-bearing papaya lines produce fruit that are marketable 1 month earlier than other cultivars.
244 Effects of Fall Urea and Copper Chelate (CuEDTA) Application on Defoliation, Reserve Nitrogen, and Spring Regrowth of `Fuji' Apple Nursery Trees
Authors: Guak Sunghee , Cheng Lailiang , Fuchigami Leslie H. , Guak Sunghee
Published: February 2019

Bench-grafted `Fuji'/M.26 trees were sprayed with 1% CuEDTA on 31 Oct., defoliated manually on 12 Nov., or allowed to defoliate naturally. Foliar urea at 3% was applied at 14 days and 9 days before CuEDTA treatment. Plants were harvested after natural leaf fall and stored at 2 °C. One set of the plants were destructively sampled for reserve N (expressed as total Kjeldahl N or soluble protein concentration) analysis, and the remaining plants were transplanted into a N-free medium in the spring without any N supply for 40 days after budbreak. CuEDTA resulted in >80% defoliation within 5 days of application. Trees defoliated with CuEDTA had lower reserve N content than naturally defoliated controls, but had higher N than hand-defoliated controls. Foliar urea application before the CuEDTA treatment significantly increased reserve N level in all tree parts, without affecting the efficacy of CuEDTA on defoliation. The extent of spring regrowth was proportional to the reserve N level of the tree. Urea-treated plants, whether hand- or CuEDTA defoliated, had more growth in the spring than hand- or naturally defoliated controls. It is concluded that CuEDTA, as combined with foliar urea, can be used to effectively defoliate apple nursery trees, and increase reserve N level and improve regrowth performance during establishment.
247 Sunlight Penetration Before and After Pecan Orchard Thinning: Its Influence on Shoot Growth, Nut Production and Quality
Authors: Herrera Esteban A. , Arreola Jesus
Published: February 2019

This study was performed during 1995, 1996, and 1997 seasons in a mature pecan orchard thinned 25% in 1993, 1994, or 1995. In the orchard section thinned in 1994, more trees were removed in 1995 to reach 50% thinning. Shoot length in eight sides of the canopy periphery was measured in each growing season. Shoot growth was increased in thinned orchard sections compared with the unthinned orchard areas. Shoot growth during 1995 and 1996 was higher for trees sections thinned 25% in 1993 and 1994. Regardless of thinning years, shoot length was lower in the north side than in other canopy sides. A trend for nut yield increment was observed in thinned orchard blocks, especially where 50% tree removal was performed. Nut quality expressed in kernel percent was more related with crop load than to thinning percent or thinning year.
255 Evaluation of the Available Moisture in `Mission' Olives
Authors: Fontes Adán Fimbres , Contreras Raúl Leonel Grijalva , de Jesús Valenzuela Ruíz Manuel
Published: February 2019

The area of olives in the region of Caborca has been increasing in the last years to 4500 ha. Olives in other regions do not need the application of water, but at Caborca, evaporation is greater than rainfall. Because of this, an experiment was conducted in 1998 to determine the optimum water requirements for olives (table olives) in a sandy loam soil (flooded irrigation). The results indicated that the greatest yield (16.27 kg/tree) was with 90% and 80% depletion (15.8 kg/tree) of the available moisture (AM) in the soil (1-m depth) and the lowest yield (8.46 kg/tree) was with 100% depletion and 60% depletion of the available moisture in the soil. The total water applied with the 90% depletion of the AM was of 146.77 cm (1.467 m).
260 Micropropagation of Baptisia bracteata Mnhl. via Direct Regeneration
Authors: Stamenova-Berberova Hristina H. , Read Paul E.
Published: February 2019

Native plants are often ignored in horticulture because they may lack major ornamental traits and many of them are difficult to propagate. Creamy indigo (Baptisia bracteata Mnhl.) is a North American legume with considerable potential as a container-grown or ornamental plant for managed landscapes. Nodal explants from aseptically germinated seedlings were evaluated for axilary shoot and leaf development. The explants were cultured on Murashige and Skoog medium (MS) containing adenine sulfate at 80 mg•L-1, 30% sucrose, and different levels of N-6-benzyladenine (BA) (0.5,1.0,2.0 mg•L-1) supplemented with indole-3-acetic acid (IAA) (0.05, 0.1 or 0.5 mg•L-1) or with IAA omitted. Shoot regeneration occurred within 2 to 3 weeks. The best medium for shoot regeneration was MS supplemented with BA at 1.0 mg and IAA at 0.1 mg•L-1. Shoots were transferred onto rooting medium consisting of Ω MS supplemented with 1.0 mg alpha-naphthaleneacetic acid (NAA) and 1.0 mg indole-3-butyric acid (IBA)/L and 20% sucrose. Rooting took place within 3 to 5 weeks. Plantlets were then planted in soil mix, placed under a polyethylene tent for 2 weeks, and transferred into the greenhouse for further growth.
278 Gas Exchange and Water Relations of Diverse Tall Fescue Cultivars in Response to Drought Stress
Authors: Huang Bingru , Gao Hongwen
Published: February 2019

To investigate shoot physiological responses to drought stress of six tall fescue (Festuca arundinacea) cultivars representing several generations of turfgrass improvement, forage-type `Kentucky-31', turf-type `Phoenix', `Phoenix', and `Houndog V', and dwarf-type `Rebel Jr` and `Bonsai' were grown in well-watered or drying soil for 35 days in a greenhouse. Net photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr), relative water content (RWC), and photochemical efficiency (Fv/Fm) declined during drought progression in all cultivars, but the time and the severity of reductions varied with cultivars and physiological factors. Pn, RWC, gs, and Tr decreased significantly for `Rebel Jr', `Bonsai', and `Phoenix' when soil water content declined to 20% after 9 days of treatment (DOT) and for `Falcon II', `Houndog V', and `Kentucky-31' when soil water content dropped to 10% at 15 DOT. A significant decrease in Fv/Fm was not observed in drought-stressed plants until 21 DOT for `Rebel Jr', `Bonsai', and `Phoenix' and 28 DOT for `Houndog V', `Kentucky-31', and `Falcon II'. The decline in Pn was due mostly to internal water deficit and stomatal closure under short-term or mild drought-stress conditions. After a prolonged period of drought (35 DOT), higher Pn in `Falcon II', `Houndog V', and `Kentucky-31' could be attributed to their higher Fv/Fm.