bluuebunny/crossref_metadata_2025 huggingface dataset:
New Gene Candidates for the Regulation of Winter Dormancy in Perennial Plants
Authors: Bielenberg Douglas G. , Wang Ying , Reighard Gregory L. , Abbott Albert G.
Published: February 2019

`Evergrowing' (evg) peach is a naturally occurring mutant unable to enter winter dormancy in response to dormancy inducing conditions. The evg mutant is one of only two described mutants affecting winter dormancy in woody perennial trees. The evg mutation segregates as a single recessive gene and previous work by our group has fine mapped the trait between flanking markers separated by 3.3 centiMorgans. This region was physically mapped using a bacterial artificial chromosome (BAC) library from and a contig of overlapping genomic fragments identified. We have utilized several approaches to complete the sequencing of a 132 kilobase region of the peach genome derived from three overlapping BACs that encompass the complete EVG gene containing region. We present here our analysis and annotation of the genomic region, including putative and experimentally verified gene coding sequences. A primary feature of the region is a large tandem duplication of a region containing a MADS-box type DNA binding transcription factor resulting in six similar copies of the gene, all of which appear to be expressed at the mRNA level in wild-type germplasm. Hybridization analysis revealed the presence of a large deletion in the mutant genome. Five of the identified genes fall within the evg mutation and represent new candidates for the control of entrance into winter dormancy.
Border Patrol: Epicuticular Leaf Wax Mediates Resistance of Azalea Genotypes (Rhododendron spp.) to Azalea Lace Bug [Stephanitis pyrioides (Scott)]
Authors: Chappell Matthew , Robacker Carol , Baden Sherrod , Byous Allen
Published: February 2019

Azalea lace bug (ALB) is a significant pest on azalea, with feeding injury causing speckling and discoloration on affected leaves. Feeding damage also results in a reduction of stomatal gas exchange and leaf chlorophyll content, postulated to diminish growth and flowering rates.

In azalea, specific lipid components of the plant cuticle have been implicated in ALB resistance of R. canescens. In this study, epicuticular leaf wax was extracted from the leaves of four azalea genotypes, divided into two groups: a resistant group including R. periclymenoides and `Fourth of July' and a susceptible group including R. austrinum and `My Mary'. Leaf wax was extracted and resuspended in solution for application to all entries in a full diallel manner, including controls of solution only and no treatment. Each genotype–solution treatment included 10 replications. The leaf wax solution was applied to each replication (leaf) by painting the solution on one side of the midrib, yet on both abaxial and adaxial surfaces. Two leaves attached to a stem and four female adult ALB were placed in separate 32-mL sealed cups. Experimental conditions were 24 °C and 12-hour daylength for 96 h, at which time the number of live adults, frass spots, and eggs were counted. Data revealed that application of leaf wax solution had an impact on the level of frass and egg deposition by ALB in both resistant and susceptible genotypes. The effect was most pronounced when a solution of resistant genotypes was placed on susceptible genotypes, as the application resulted in lower numbers of frass spots and eggs compared to the nil control. However, an increase in frass and eggs was observed when extract of susceptible genotypes was applied to resistant genotypes.
High and Dry Research in the Front Range, Colorado
Authors: Badertscher Kerrie B. , Shonle Irene , Vickerman Larry , Hall Gary
Published: February 2019

The purpose of this study was to gain knowledge about the establishment of drought-tolerant species at high elevations and with no irrigation. Colorado State University Cooperative Extension (CE) had no research-based information about the establishment of no-water gardens, a topic of much relevance in times of drought and for mountain communities with watering restrictions. Research-based information about plant establishment at 7500 feet elevation and above is extremely limited. Test gardens were planted with a standardized planting pallet and in such a way as to be aesthetically pleasing. Each plot was approximately 400 square feet and contained shrubs, perennials, grasses, seeds, and bulbs. A review of the first full year and second growing season will be given along with outreach strategies.
The Effect of Short Days on Cold Acclimation in Gaura
Authors: Pietsch Grace M. , Li Paul H. , Anderson Neil O.
Published: February 2019

Cold acclimation has been extensively studied in woody species such as Cornus sericea and Malu × domestica. These studies have shown that cold acclimation is initiated by short days and completed with the addition of a cold treatment. It is unknown whether herbaceous perennials respond in a similar manner to these environmental cues. Our research objective was to examine short day photoperiod effects on cold acclimation in herbaceous gaura populations collected at different latitudes. Gaura drummondii collected in Texas, and Gaura coccinea collected in Minnesota and Texas were clonally propagated, grown under a 16-hour long day photoperiod and 25/20 °C [day/night (D/N)] temperature for 8 weeks. Plants were then subjected to 0, 1, 2, 3, 4, or 5 weeks of 8-hour short days at 20/15 °C (D/N) temperatures. Cold acclimation was determined using electrolyte leakage (freezing stem pieces from –1 to –9 °C) and measuring electrical conductivity after treatment and tissue death. Mean separations showed two distinct statistical groupings of 0-2 weeks and 3–5 weeks of short days for Minnesota gaura, whereas Texas gaura overlapped for 0–5 weeks of short day treatments. It is unknown what environmental cue(s) initiate cold acclimation in Gaura native to southern latitudes such as Texas.
Effects of S-ABA on Water Loss and Desiccation of Containerized Hibiscus rosa-sinensis
Authors: Stamps Robert H. , Chandler Annette L.
Published: February 2019

Desiccation of containerized plants at retail outlets due to inadequate watering is a recurring problem. Water stress can decrease plant quality and survivability. Treatments that could reduce plant transpiration without lowering plant quality could be beneficial in maximizing the likelihood that plants would not become water stressed between waterings at retail outlets. Abscisic acid (ABA) is known to be involved in the regulation of stomatal aperatures, the major control mechanism for transpirational water loss. Containerized plants of four cultivars of hibiscus were thoroughly sprayed with S-ABA at concentrations of 0, 125, 250 or 500 mg·L–1. Plants were held under simulated retail conditions and were not watered until visible wilting occurred. Transpiration and pot weights were monitored over time. Transpiration rates and weight loss percentages were negatively correlated with S-ABA concentrations. Effects on transpiration rates lasted for at least 30 hours after treatment. For mean hours to wilt, there was interaction between S-ABA treatments and cultivars. For the most sensitive cultivar (`Double Apricot'), treatment with S-ABA at 500 mg·L–1 almost doubled the time to plant wilt (130 h) compared to the control treatment (72 hours). Hours to wilt was increased 24% for `Double Pink' treated at the highest rate. For `Double Red' and `Single Pink', hours to wilt was not affected by treatments. For some hibiscus, S-ABA treatments prior to placement of plants at retail outlets might decrease the chances that the plants would become severely water stressed.
Mechanism and Underlying Physiology Perpetuating Alternate Bearing in Citrus
Authors: Verreynne Johannes S. , Lovatt Carol J.
Published: February 2019

Alternate-bearing trees produce a heavy on-crop followed by a light off-crop. Whereas climatic events initiate alternate bearing, it is perpetuated by endogenous tree factors. For citrus, the mechanism and underlying physiology by which fruit influence floral intensity the next spring was unresolved. To determine whether reduced return bloom of on-crop trees was due to inhibition of vegetative shoot production and, thus, a lack of “wood” on which to bear next spring's inflorescences or, alternatively, to inhibition of phase transition and inflorescence development on an adequate number of vegetative shoots, fruit were removed from individual shoots monthly or from entire on-crop `Pixie' mandarin trees during periods critical to shoot initiation (summer) and phase transition (winter). Fruit removal provided clear evidence that the on-crop exerted a significant effect on return bloom during the summer by reducing summer–fall shoot growth and, hence, the number of flowers borne on these shoots as well as on old wood of fruit-bearing shoots. The on-crop had less effect in winter on phase transition and return bloom. Buds collected during the summer from on-crop `Pixie' mandarin trees were characterized by high indoleacetic acid and low isopentenyladenosine concentrations compared to buds from off-crop trees. The starch level of the buds was not affected. No differences in hormone concentrations were detected for buds collected during winter from on- and off-crop trees, but buds of on-crop trees had less starch. The results demonstrate that the on-crop reduces return bloom predominantly by inhibiting summer-fall vegetative shoot growth by a mechanism similar to apical dominance, not a lack of available carbohydrate.
Developmental Changes in Cucumber Fruit Susceptibility to Infection by Phytophthoracapsici
Authors: Ando Kaori , Grumet Rebecca
Published: February 2019

Phytophthoracapsici, a soil-borne oomycete pathogen causing fruit rot in cucumber, has become a limiting factor for cucumber production in the Midwest. In the process of screening plant introductions (PIs) for resistance to P. capsici, it appeared that degree of susceptibility might decrease as fruits develop. To examine this more carefully, detached, greenhouse-grown, hand-pollinated `Vlaspik' fruits aged 2–18 days post-pollination (dpp) were inoculated with P. capsici mycelium and evaluated for symptoms. There was a reproducible decrease in susceptibility with increasing fruit age. The fruits that sporulated were usually younger and smaller (2–9 dpp), 10-3 dpp fruit tended to develop water-soaked symptoms, while the fruits that remained symptom-free were usually older (>14 dpp) and oversized for pickling cucumber. The transition from susceptible to more resistant appeared to occur at the end of the period of rapid fruit elongation. Detached field-grown `Straight Eight' fruits showed similar size-related trends. Candidate resistant genotypes identified from the PI screening were re-screened using 7 and 14 dpp fruits. Again an age-dependent difference in response was observed, indicating that the increase in resistance is not genotype-specific. Furthermore, field observations suggest a gradation of susceptibility within the fruits as the blossom end was most frequently infected. Preliminary tests of detached greenhouse-grown, hand-pollinated fruits suggested that as the fruits grew older, the blossom end remained susceptible longer than the stem end. These findings could have implications for appropriate screening methods, the stage of fruit likely to become infected in the field, and appropriate spray practices.
Inter- and Intra-specific Variation in Growth Parameters of Ocimum Species
Authors: Mentreddy Rao , Sims Cedric , Devagiri Usha , Cebert Ernst
Published: February 2019

Basils (Ocimum species) of the mint family Lamiaceae are well known for their multiple uses as culinary, aromatic, and medicinal plants worldwide. Basils are integral components of Asian and Mediterranean cuisine and are also widely used for treating diabetes and cancers. Basil has a limited acceptance as a culinary herb in the United States. The potential exists for development of culinary, medicinal, aromatic, and ornamental basil cultivars for production in the southeastern United States. In a preliminary field trial, 84 accessions belonging to six species of the genus Ocimum were evaluated for agronomic parameters in single-row plots. Wide variations exist between and within species for all agronomic traits studied. The mean percent emergence between species ranged from 60.0% for O. americanum var. americanum to 100.0% for an unknown species from Italy and O. campechianum. The aboveground fresh biomass per plant ranged from 424.0 g for O. sellol to 1450.3 g for the unknown Italian accession. The unknown Italian accession produced more branches per plant and also had the highest root, leaf, stem, and inflorescence fresh and dry weights among species. Ocimumsellol plants emerged late, had a slower rate of emergence, and produced a lower total biomass than other species. Ocimumgratissimum partitioned a greater proportion of the total dry weight to leaves (37.9%) and roots (14.4%), whereas O. basilicum. O americanum var. americanum, and O. campechianum partitioned a greater amount of dry matter to inflorescence and the least to roots than other species. In this presentation, the agronomic traits and basil cultivars with potential for ornamental and medicinal purposes will be discussed.
Identification of Unique Reproductive Characteristics in Six Pawpaw Populations for Germplasm Enhancement
Authors: Crabtree Sheri B. , Pomper Kirk W. , Geneve Robert L.
Published: February 2019

The North American pawpaw [Asiminatriloba (L.) Dunal] is a tree fruit native to the eastern and midwestern areas of the United States. The fruit has a rich, unique flavor and pawpaw has great potential as a new fruit crop. Kentucky State University (KSU) in Frankfort is the site for the USDA National Clonal Germplasm Repository (NCGR) for Asimina species, containing over 1700 accessions from 17 different states. The objective of this study was to evaluate the diversity in reproductive characteristics for pawpaw accessions in the KSU-USDA repository orchard from six geographic regions (Ind.-site 1, Ind.-site 2, Ky., Md., N.Y., and W.Va.). Data were collected in 2002, 2003, and 2004 for trunk cross-sectional area, total number of flowers, length of flowering, flowering peak, fruit set, total number of clusters, total number of fruit, number of fruit per cluster, average fruit weight, yield, yield efficiency, length of harvest, harvest peak, and growing degree days required for ripening. Significant differences in characteristics were found within and among populations for the various regions. Accessions from Kentucky and West Virginia had the latest flowering peaks. Trees from Maryland had the highest fruit weight in 2002, whereas the West Virginia population produced the largest fruit in 2004. The New York accessions consistently had the latest harvest peak and required the fewest growing degree days for ripening. Correlations were also found between several vegetative and reproductive characteristics. This study suggests that a significant level of reproductive diversity exists within KSU's repository collection that could be used in future breeding strategies for cultivar improvement.
Ethylene Exposure and 1-MCP Protection for Tulip Bulbs during Storage
Authors: Liou Susan S.C. , Miller William B.
Published: February 2019

During transportation and storage of Dutch tulip bulbs, potential ethylene exposure could lead to flowering abnormalities, including accelerated flowering, shortened plant heights, and in the most extreme case, flower abortion. Sources of ethylene include Fusarium-infected bulbs, deteriorating tissues, and combustion engines. Treatment with 1-MCP (1-methylcyclopropene) may prevent ethylene action as 1-MCP occupies ethylene specific receptors on target tissue. Two aspects of this problem were quantified using four tulip cultivars: duration of ethylene exposure necessary to induce damage as well as the effective period of protection by 1-MCP against ethylene. Flower abortion appeared in susceptible cultivars after ≥9 days of ethylene exposure (10 ppm) and was only found in mature bulbs (late November). The effective protection period of 1-MCP against ethylene (2-week exposure of 10 ppm) was determined, using flowering percentages, to be as long as 4–7 days in young bulbs and 28 days for older bulbs. Effects of ethylene on other flower attributes and implications of these findings in industry practices will be discussed.
Flood Water Temperature and Duration Affect Nonstructural Carbohydrate Concentration of Cranberry Uprights and Roots
Authors: Vanden Heuvel Justine E.
Published: February 2019

Flooding is often used as a pest management tool in cranberry production. The “Late Water” flood is a 1-month flood held on some Massachusetts bogs from mid-April to mid-May, and has anecdotally been related to poor vine performance. The flood was simulated at 11 °C and 21 °C on potted cranberry uprights (cv. Stevens). Over the course of the 1-month flood, total nonstructural carbohydrate concentration (TNSC) of the upright tissue decreased by 23% and 50% in the 11 °C and 21 °C treatments, respectively. Decreases in upright TNSC in the 11 °C treatment were mostly due to a substantial decrease in sucrose, while in the 21 °C treatment, sucrose, glucose, fructose, and starch all decreased significantly over the course of the flood. The greatest decrease in upright TNSC in the 11 °C treatment occurred during the first week of the flood, while in the 21 °C treatment, the greatest decrease occurred during the fourth week. Root TNSC was not affected by flooding in the 11 °C treatment, but was reduced by 39% in the 21° C treatment. Two weeks following removal from the 1-month flood, uprights in the 11° C treatment contained 9% more TNSC than uprights in the 21 °C treatment, while root TNSC from the two treatments was similar. No temperature treatment differences were evident in the uprights or roots by harvest.
Correlation between Glassy-winged Sharp Shooter Feeding Preference and Pierce's Disease Development on Grapevines
Authors: Lu Jiang , Clarke Elvis , Ren Zhong-bo
Published: February 2019

Although some of the American native Vitis species and their hybrids, particularly those originated from the southeastern United States, have been known for resistance to Pierce's disease (PD), their resistant status against the glassy-winged sharp shooter [GWSS, Homalodisca coagulata (Say)], the vector transmitting PD pathogen (Xylellafastidiosa Well), has not been reported. To determine GWSS feeding preferences on different grape species/cultivars and correlations of feeding to Pierce's disease development, a survey was conducted at Florida A&M University, Tallahassee. The feeding preference of GWSS on different species/cultivars was evaluated in two different ways: 1) count the number of GWSS on different grapevines in the field; and 2) determine the feeding preference by measuring the excretion of the GWSS feeding on difference grape species/cultivars, including highly susceptible V. vinifera cultivars, native American grape species and hybrids, and muscadine grapes. Results from this study indicated that the frequency of GWSS visits on different grapevines varied among the species/cultivars investigated. For example, PD-resistant grape V. rotundifolia (muscadine grape) had significantly fewer GWSS visits than did the PD-susceptible V. vinifera grape. The frequency of GWSS visits to V. labrusca, the native American grape susceptible to PD, was intermediate between those found on V. rotundifolia and V. vinifera. Similarly, the GWSS sucked more xylem sap when they fed on PD-susceptible grapevines than on PD-resistant ones. Overall, there is a positive correlation between the GWSS visits/feeding and the status of grapevine resistance/susceptibility to Pierce's disease.
The Effect of Surround WP on Apple Productivity and Fruit Quality in a Vermont Apple Orchard
Authors: Garcia M. Elena , Berkett Lorraine P. , Bradshaw Terry
Published: February 2019

Surround WP, a kaolin clay-based biopesticide product, is a potential alternative to some organophosphates used in apple orchards for the management of pests, such as codling moth. In addition, Surround has been reported to have important nontarget horticultural impacts because of its effect on canopy temperature reduction. The label for use of Surround states: “When applied at recommended rates and frequencies, benefits such as increased plant vigor and improved yields may occur in certain apple cultivars.” However, most of the research on nontarget effects has been conducted in warmer, semiarid environments. The objectives of this 3-year (2002–04) interdisciplinary research project were to determine potential nontarget effects of Surround WP application on apple tree vigor, productivity, and fruit quality in the relatively cool and moist climate of the Northeast. The research was conducted at the UVM Horticultural Research Center in South Burlington, Vt., on `McIntosh'/M26 trees. The experiment used a completely randomized design with five treatments replicated six times. Each replicate consisted of single tree plots. Treatments included: 1) Surround beginning at green tip plus fungicides; 2) Surround beginning at green tip without fungicides; 3) Surround beginning at petal fall plus fungicides; 4) standard IPM; and 5) nontreated control. Results indicate no significant differences among treatments 1, 3, and 4 (treatments that included fungicide applications) in vegetative shoot length, spur characteristics, blossom number, fruit weight, firmness, soluble solids, and fruit calcium levels. Trees treated with Surround had significantly lower yield efficiencies in 2003 and 2004 than trees under IPM treatment.
TREESTRESS: A Within Canopy Spatial Distribution Model for Simulating the Carbon and Water Exchange Response to Atmospheric Thermal and Rhizospheric Water Stress
Authors: Bauerle William L. , Rajaraman Nilakantan S. , Anantharamu Shruthi , Bowden Joseph D.
Published: February 2019

A model (TREESTRESS, a spatially explicit 3-D process-based model) for simulating the spatial distribution of intracanopy photosynthetic and transpirational responses to multiple stress factors is presented. The model includes intracrown validation on both deciduous and coniferous radiation transfer, incorporation of temperature response functions of Rubisco-, mesophyll-, and RuBP-limited photosynthesis to the widely used Farquhar et al. (1980) photosynthesis model, and a rhizospheric water stress submodel to constrain the Ball-Berry stomatal conductance submodel. The model also includes functions that account for acclimation and/or no acclimation to growth temperature. Taken together, the model aims at predicting spatially explicit intracrown response to multiple stresses (primarily temperature, water, and radiation stress). The model was parameterized for red maple trees under nursery conditions and validated by sap flow, photosynthesis, and radiation measurements. The integration of multiple stress response functions in a spatially explicit process-based model could provide a proficient method to simulate stress interactions and predict carbon uptake and water use in crowns, canopies, ecosystems, and landscapes.
Absorption of 1-MCP by Nontarget Materials during Storage
Authors: Vallejo Fernando , Beaudry Randolph
Published: February 2019

We tested the sorptive capacity of a number of nontarget materials found in apple storage rooms on their capacity to remove 1-MCP from the storage atmosphere and thereby compete with the fruit for the active compound. Furthermore, we evaluated the impact of temperature and moisture. Nontarget materials included bin construction materials [high density polyethylene (HDPE), polypropylene (PP), weathered oak, nonweathered oak, plywood, and cardboard] and wall construction materials (polyurethane foam and cellulose-based fire retardant). Each piece had an external surface area of 76.9 cm2. We placed our “nontarget” materials in 1-L mason jars and added 1-MCP gas to the headspace at an initial concentration of ≈30 μL·L-1. Gas concentrations were measured after 2, 4, 6, 8, 10, and 24 hours. The concentration of 1-MCP in empty jars was stable for the 24-hour holding period. Little to no sorption was detected in jars containing dry samples of HDPE, PP, cardboard, polyurethane foam, or fire retardant. Inclusion of plywood, nonweathered oak, and weathered oak lead to a loss of 10%, 55%, and 75% of the 1-MCP after 24 hours, respectively. Using dampened materials, no sorption resulted from the inclusion of HDPE, PP, polyurethane foam, or the fire retardant. However, the rate of sorption of 1-MCP by dampened cardboard, plywood, weathered oak, and nonweathered oak increased markedly, resulting in a depletion of ≈98%, 70%, 98%, and 98%, respectively. The data suggest that there are situations where 1-MCP levels can be compromised by wooden and cardboard bin and bin liner materials, but not by plastic bin materials or typical wall construction materials.
Effect of Storage Conditions and Genotype on Shelf-life of Fresh Southernpea
Authors: Butcher Justin , Morelock T.E. , Williams D.R.
Published: February 2019

Fresh-shelled southernpeas [Vignaunguiculata(L.) Walp.] is a popular vegetable. Postharvest storage of fresh-shelled peas is a crucial step in the production process. Farmers strive to produce a product that is high in quality and freshness with appropriate texture and appealing color. Improper storage and handling of southernpeas will result in deterioration. In an effort to prevent potential losses of southernpeas, this study was conducted to determine the best method to ship and store shelled peas. Five southernpea varieties: `Early Acre', `Early Scarlet', `Excel Select', `Coronet', and `Arkansas Blackeye #1' were planted in a randomized block design at the University of Arkansas. Twelve mature green pods of each variety were subjected to a sweated and unsweated treatment and then shelled. After shelling, seed were subjected to four different environmental conditions, and each treatment was evaluated for changes in physical appearance. Objectives of the study were to determine the best variety and environmental condition to maintain a quality marketable product. The study showed that a refrigerated environment at or near 3 to 5 °C allowed the crop to be stored for up to 2 weeks. It also appeared that sweating assisted with the shelling process and maintained appearance of each variety longer.
Liquid Effluent from Thermophilic Anaerobic Digestion of Poultry Litter as a Potential Fertilizer
Authors: Liedl Barbara E. , Bombardiere John , Stowers Amanda , Mazzaferro Kari , Chatfield J. Mark
Published: February 2019

Increasing production of agricultural waste impacts health, economic, and environmental welfare. Thermophilic anaerobic digestion is a technology developed to treat these waste streams whereby the organic material is converted to biogas and effluent. The effluent, available in solid and liquid form, holds promise as a fertilizer. Digested (broiler litter) liquid effluent was compared to chemical and certified organic fertilizers with application rates based on soil analyses and crop recommendations. An unfertilized control and an effluent treatment at twice the recommended amount were also included. Beds treated with liquid effluent maintained higher levels of available phosphorus established from treatment in prior years with solid effluent. Beds treated with liquid effluent showed a significant increase in K, Mg, Cu, and Mn. Potato fresh weight and tuber number for 2× effluent beds were significantly better than the other treatments. Average tuber weight was also statistically significant, but organic, 2×, and 1× effluent were best. For tomato, the 2× effluent treatment was statistically better for fruit number, average weight, and total weight. In fact, the total weight per plant for the 2× effluent treatment was more than three times higher than the other fertilizer treatments. The chemical and effluent treatments were statistically better for broccoli than the organic or unfertilized control. Blueberry yields were not significantly different between treatments. As this is a perennial crop, it may be several years before a significant difference is observed. While not a total solution, our research shows the effectiveness of digested poultry litter as part of a nutrient management program, thereby making a safer, less-polluting alternative to raw livestock residuals.
Experiential Education Employed to Demystify Food Irradiation as a Viable Technology for Food Industry Professionals
Authors: Vestal Tom A. , Dainello Frank , Wingenbach Gary J. , Laminack Janet
Published: February 2019

Research shows that food irradiation is a safe food technology effective in reducing pathogenic microorganisms, prolonging shelf-life, and controlling pests, such as fruit flies, to avoid quarantine. However, this technology may not be understood widely by food industry professionals. The purpose of this research was to study the effectiveness of professional development designed with a variety of experiential education strategies targeting food industry regulators, Extension agents, and others in the food industry. The workshop, Improving Safety of Complex Food Items Using Electron Beam Technology, included presentations by experts in food irradiation technology, tours of food irradiation facilities, group activities, and a taste-test of irradiated meats and produce. Data were collected from 19 males and 3 females in the paired workshop pre- and post-tests which assessed participants' knowledge, perceptions, and concerns about food safety and food irradiation, using Likert-type scales. The workshop produced significant knowledge gains. Respondents' perceptions of food safety and food irradiation issues were improved significantly as a result of participation in the workshop. Also, respondents' perceived knowledge and understanding of food safety, food irradiation, and the technology behind food irradiation improved significantly upon completion of the workshop and post-test.
Yield and Microbial Quality of Iceberg Lettuce as Affected by Moisture at Harvest
Authors: Fonseca Jorge M.
Published: February 2019

The effect of moisture conditions on yield and microbial quality of iceberg lettuce was investigated. Iceberg lettuce cvs. Honcho II and Sahara grown at the Yuma Agricultural Center were evaluated for weight, diameter, microbial population, and postharvest quality, either following different irrigation termination schedules or before/after a rainfall event. Two trials were conducted with early (24 or 18 days before harvest), middle (16 or 8 days before harvest) and late (6 or 4 days before harvest) irrigation termination. Lettuce receiving the last irrigation 6–4 days before harvest showed increased weight and diameter, higher total aerobic bacteria and shorter shelf life than plants having the early irrigation termination. The plants receiving middle termination irrigation showed similar weight at harvest, lower total aerobic count and longer shelf life than plants receiving late irrigation termination. The effect of the field's moisture prior to harvest on quality was further evaluated with lettuce harvested before and 1, 2 and 7 days after a rainfall event. After rain, mesophilic bacteria population increased 1 log10 CFU/g in outer leaves and more than 2 log10 CFU/g in head leaves. The microbial population in outer leaves declined more rapidly, possibly due to more rapid drying and higher impact of sun UV light. The results from this study suggest that managing moisture conditions at harvest is important to enhance quality of lettuce. Although the potential decrease in weight produced with an early irrigation termination is a great concern of growers, it was shown in this study that excessively late preharvest irrigation of lettuce is not necessary to obtain maximum weight at harvest.
Antagonistic Effect of Lactic Acid Bacteria on Microflora of Shredded Cabbage in High CO2 Modified Atmosphere Packaging
Authors: Izumi Hidemi , Tachibana Moritoshi , Ohnishi Keiko , Kobata Takashi , Hamanaka Daisuke
Published: February 2019

Shredded cabbage was packaged in four types of non-perforated and perforated OPP films with initial 10% CO2. In the perforated OPP film with a O2 permeability of 25,000 mL/m2 per day/atm, CO2 remained at about 10%, O2 decreased to 13%, and the shreds showed the best organoleptic quality after 4 days of storage at 10 °C. The bacteria isolated from the shredded cabbage in the perforated MA package were predominantly Gram-negative rod-forms including Enterobacteriaceae and phytopathogenic bacteria, while only lactic acid bacteria (Leuconostoc citreum) was isolated as Gram-positive bacteria. For biological control of the pathogens, two lactic acid bacteria strains (Leuconostoc mesenteroides subsp. mesenteroides and Pediococcus acidilactici) were selected from bacteriocinogenic 6 strains, based on the growth in culture broth under 5% to 20% CO2 atmospheres. Shredded cabbage was inoculated with these two bacteriocin-producing strains, packaged in 10% CO2 perforated MA packaging, and stored at 10 °C. The growth of coliforms and psychotrophic aerobic bacteria was reduced due to antagonistic effect of lactic acid bacteria and the quality of shreds was not affected detrimentally by the strains. These results indicate that the combination of added bacteriocin-producing lactic acid bacteria and 10% CO2 perforated MAP was useful in biopreservation of shredded cabbage.
Pecan Cultivation in China
Authors: Zhang Riqing , Lv Fangde , He Fang , Xie Bixia , Wang Lingdan
Published: February 2019

Pecan [Carya illinoinensis (Wangenh.) C. Koch], a world-famous nut tree native to North America, was introduced to China in the early 1900s. However, little success had been recorded in terms of its nut production. Based on comparative studies of the geoclimate, soil conditions, and growth and performance of the pecan crop between southeastern U.S. and China, as well as in 12 other countries with successful pecan cultivation, it is feasible to grow pecan in China within the latitudes 25–35°N. In these areas, the summer temperatures range from 25–35°C with lower DIF. The annual precipitation is 500–1500 mm. Further studies using the Dendroclimate Predicative Analysis of water and heat conditions in the U.S. Pecan Belt, which is composed of seven factors, including the annual mean and extreme low temperatures, annual frost-free days, and annual precipitation, concluded that four pecan cultivation regions should be designated in China. These regions were the Favorable Region (I), the Northern and Southern Suitable Regions (IIa, IIb), the Northern and Southern Marginal Regions (IIIa, IIIb), and the Northern and Southern Undesirable Regions (IVa, IVb). The Favorable Region is along both sides of the Yangtze River in-between latitudes 25–35 °N and longitudes 100–122 °E. Some areas with microclimates, such as western Yunnan, nourish several pecan cultivars and have demonstrated a promise of pecan production. The demand for pecan is high in China, and this regionalization of pecan cultivation will ultimately enhance further collaboration on pecan production between horticulturists in China, United States, and other countries. Future research will result in the introduction of much better pecan cultivars to the different cultivated regions in China.
(24) Varietal Apple Wines from Great Plains-grown Cultivars
Authors: Lattrell Patricia , Smith Durward A. , Read Paul , Cuppett Susan S.
Published: February 2019

There is little information regarding processing methods that result in quality and uniformity in varietal apple wines. The object of this research was to determine if apple cultivars grown in the Great Plains region could be used to produce premium quality single cultivar wines, and to establish efficient processing methods that optimize quality. The qualities of single cultivar apple (Malus ×domestica) wines were investigated, including chemical characteristics of the apple juices, e.g. total soluble solids, acidities, and tannin contents. Analyses were performed on the fresh juices, fermenting juices, wines held for 6 months, and the aged wines. Fermentable sugar content was increased either by the addition of sucrose or by the addition of concentrated juice of the same apple cultivar. An optimized method of purge and cold trapping injection capillary gas chromatography was applied to the analysis of some volatile constituents. Profiles of the wine volatiles were analyzed to determine differences among cultivars. The harsh flavors and yeasty odors of the wines diminished after 6 months of storage. Acidity and volatile acidity increased slightly during storage. Tannin contents, fermentation efficiencies and volatile profiles differed among varieties. This research indicated that some apple cultivars grown in the Great Plains produce acceptable single cultivar wines.
(57) Bioassays and Small-scale Greenhouse Experiments Conducted to Evaluate the Suppression of Phytophthora cinnamomi Activity on Rhododendron × PJM `Elite' by Different Composts Incorporated into Growing Media
Authors: Han Jae H. , Good George L. , Nelson Eric B. , Van Es Harold M.
Published: February 2019

Composts vary in their ability to suppress disease activity when incorporated into growing media. Bioassays that enable a reliable and quick assessment of compost's ability to suppress disease activity can save time, funds and space. A bioassay using Lupinu× `Russell Hybrid' seedlings was evaluated as a short-term test for gauging the ability of three composts to suppress activity of P. cinnamomi. Colonized millet seeds were prepared via the V-8 agar method. The colonized millet seed were incorporated into the potting media at 0, 50, 100, 200, and 400 colonized millet seed/200 cc of the media used. Three composts, including composted sewage sludge, brewer's waste and cow manure, were incorporated into the media (50% sand: 50% sphagnum peat, by volume) at rates of 0%, 10%, 25%, and 50%, by volume. The media, including the inoculated millet seed, were placed in small plastic pots (7.6-cm-diameter and 6.7 cm high), after which 10 Lupine seeds were sowed in each pot. Percentage of seedling loss was determined after 43 days of observation. The composted sewage sludge and the cow manure proved suppressive at the 50% incorporation rate and the 10% and 25% rate of the latter compost. The brewer's waste compost proved ineffective in this regard; thus, research with this product was discontinued. In a greenhouse study the same inoculation and compost incorporation rates were used, but rooted cuttings of Rhododendro × PJM `Elite' were plotted into the various treatments. Suppression of disease activity by the composts was significant 2 and 4 months after initiation of treatments. Significance in disease suppression noted between these treatments decreased significantly during the fifth month of the experiment.
(54) Response of Betulanigra `BNMTF' to Foliar and Drench Applications of Nickel
Authors: Ruter John M.
Published: February 2019

Mouse ear disorder on container-grown river birch (Betulanigra L.) is a national problem caused by a deficiency of nickel. Symptomatic plants have leaves which are small, wrinkled, darker green, cupped, and have necrotic margins. Research showed that mouse ear could be cured by applications of nickel sulfate (Ruter, 2004). Further research was needed to determine optimal rates of application for sprays and drenches and to determine if phytotoxicity occurs at high rates. A study was initiated at a nursery in South Georgia on 25 June 2003, using river birch in their second growing season in #15 containers. Plants were selected for uniformity of mouse ear disorder. Treatments included a control, urea (0.24 g·L-1) + surfactant (1.0 mL·L-1), 250, 500, 750, and 1000 mg·L-1 nickel sulfate sprays, and substrate drenches applied at 150 and 300 mg of Ni/pot. After 30 days, all plants treated with nickel sulfate had 100% normal growth, except the 150 mg of Ni/pot drench, which had 79% of the canopy showing normal growth. No phytotoxicity was noted. Plants receiving foliar sprays had a 66% to 72% increase in leaf area, a 64% to 68% increase in leaf dry mass, a 31% to 44% increase in stem length, and a 9% to 17% increase in specific leaf area compared to nontreated plants. Drench treatments increased leaf area up to 62%, leaf dry mass to 55% and stem length up to 29% over control plants. Nickel in the foliage of nontreated plants was 2.3 mg·kg-1. For the spray treatments, foliar Ni ranged from 5.5 mg·kg-1 for the 250 mg·L-1 treatment to 9.3 mg·kg-1 for the 1000 mg·L-1 treatment. Though plants at the high rate of drench treatment resumed normal growth, foliar Ni levels were not different from control plants. In general, if plants were treated with Ni, then foliar B, Fe, and Zn decreased.
(58) Suppression of Phytophthora cinnamomi Activity on Rhododendro × PJM `Elite' by Two Compost-amended Container Media under Two Irrigation Regimes and Nursery Conditions
Authors: Han Jae H. , Good George L. , Nelson Eric B. , Van Es Harold M.
Published: February 2019

Composted municipal biosolids were incorporated into a potting mix containing sphagnum peat and sand (1:1 by volume) at rates of 0%, 25%, and 50%, by volume. A second medium was prepared by mixing cow manure compost in the same basic mix at rates of 0%, 10%, and 25% by volume. Each mix was inoculated with P. cinnamomi colonized millet seed at a rate of 200/200 cc of compost-amended media. The potted plants were placed outdoors under nursery conditions 14 July 2003. One half of the plants were irrigated every day, except when natural precipitation occurred; the other half was watered once each week. Soil water potential of all treatments was measured daily with tensiometers. Plants were harvested on 18 Aug. and 21 Oct. 2003, when the experiment was terminated. Frequent rainfall during the period prior to the first harvest masked any impact that the irrigation treatments may have had on disease suppression. Even so, three compost treatments proved successful in suppressing disease activity. Between the first and second harvest dates rainfall was significantly less frequent; thus, differences in P. cinnamomi activity between the wet and dry regimes was noted at the 21 Oct. harvest. Under the dry regime, all inoculated compost treatments, except the 25% municipal biosolid compost, exhibited disease suppression based on root symptom severity and percentage of root infection. Suppression based on shoot symptoms and percentage of shoot loss was evident only in the 50% and 25% biosolid and cow manure composts, respectively. Under the wet regime, only one treatment exhibited suppression of disease activity. All compost treatments held more water particularly at lower moisture tensions. The presence of more water would tend to favor more disease activity and not suppression.
(60) Rooting Stem Cuttings in Compost Tea and Anaerobic Digestion Wastewater
Authors: Chong C. , Yang J. , Holbein B. E. , Voroney R. P. , Zhou H. , Liu H.-W.
Published: February 2019

Cuttings of sage (Salviaofficinalis `Tricolor'), currant (Ribesaureum), euonymus (Euonymus fortunei var. vegetus), and weigela (Weigela florida `Nana Variegata') were rooted under greenhouse conditions (40% shade) and mist in aerated hydroponic solutions consisting of deionized water, or mixtures of deionized water and nutrients with various levels of electrical conductivity (EC, 0.0625, 0.125, 0.25, and 0.5 dS·m-1) from each of three sources: compost tea from municipal solid waste; wastewater from anaerobic digestion of municipal solid waste; and Hoagland's (control) nutrient solution. Despite differences in species response, rooting tended to be similar with the three nutrient sources. Euonymus rooting percentage increased linearly with increasing EC and was similar with all three nutrient sources (common regression curve, 61% rooting at 0.5 dS·m-1), as did root length (1.4 cm at 0.5 dS·m-1), but root number was unresponsive. Currant rooting percent increased curvilinearly and similarly with nutrient sources (87% calculated maximum rooting at 0.25 dS·m-1), but root number and length were unresponsive. Sage rooting percentage and root number also increased curvilinearly and similarly with nutrient sources (common regression curve, 100% rooting at 0.34 dS·m-1, and 4.1 roots at 0.38 dS·m-1, respectively), as did also root length with the compost tea and Hoagland's (common curve for these two nutrient sources, 11.0 cm at 0.30 dS·m-1), but was unresponsive to wastewater. Weigela was unresponsive to EC or nutrient sources (mean percentage of rooting, 73; root number, 6.5; and root length, 1.9 cm).
(180) Effects of Plant Density on Pickling Cucumber Fruit Quality
Authors: Ngouajio Mathieu , Hill Erin C. , Chase William
Published: February 2019

Cucumber is an important vegetable in Michigan, where it is grown for slicing (fresh) or processing. Michigan is the top producer of pickling cucumbers in the United States, with over 27% of the total national production. Studies were conducted in 2004 to test the effects of plant density on cucumber fruit quality. Cucumber var. `Vlaspik' was seeded in 30.5, 45.7, 61.0, and 76.2 cm rows with 12.7 cm spacing between plants inside the row, corresponding to final plant populations of 258, 172, 129, and 103 thousand plants/ha, respectively. The experiment used a randomized complete-block design with 4 replications and four rows per plot. At harvest, 10 fruits of grade 2 were randomly selected from each plot for measurement of specific gravity, firmness, soluble solids, color, and seed size. Cucumber fruit specific gravity, soluble solids, and seed size were not affected by plant population size. However, fruit firmness and color varied with plant density. Low plant populations, when compared to high populations, produced darker green fruits, a desired trait in pickling cucumber production. On a scale of 0 (yellowish) to 5 (dark green), plants grown under a population of 258 thousand plants/ha scored an average of 2.8. The score was 4.6 for fruits produced in plots with 103 thousand plants/ha. Low plant populations increased fruit firmness as measured by a puncture test. Fruit firmness was 89, 93, 97, and 95 g·mm-2 for 258, 172, 129, and 103 thousand plants/ha, respectively. Results suggest that cultural practices may affect pickling cucumber fruit quality.
Line 63-1: A New Virus-resistant Transgenic Papaya
Authors: Tennant Paula , Souza Manoel T. , Gonsalves Dennis , Fitch Maureen M. , Manshardt Richard M. , Slightom Jerry L.
Published: February 2019

The disease resistance of a transgenic line expressing the coat protein (CP) gene of the mild strain of the papaya ringspot virus (PRSV) from Hawaii was further analyzed against PRSV isolates from Hawaii and other geographical regions. Line 63-1 originated from the same transformation experiment that resulted in line 55-1 from which the transgenic commercial cultivars, `Rainbow' and `SunUp', were derived. Plants of line 63-1 used in this study consisted of a population from a self pollinated R0 bisexual plant. ELISA and PCR tests provided evidence that there are at least two segregating CP loci. To allow for comparison with reactions of the previously reported line 55-1, virus isolates from Hawaii, Brazil, Thailand, and Jamaica were used to challenge seedlings of 63-1. Unlike line 55-1, a significant percentage of inoculated transgenic plants were susceptible to isolates from Hawaii. However, a proportion of plants were resistant to the non-Hawaiian isolates. In contrast, previous work showed that all plants of the hemizygous line 55-1 were susceptible to PRSV isolates from Brazil, Thailand, and Jamaica. Line 63-1, therefore, presents Hawaii with PRSV-resistant transgenic germplasm that could be used as a source of transgenes for resistance to PRSV isolates within and outside of Hawaii.