bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Cyclic Cold Temperature Stress on Watermelon Seedling Growth, Earliness, Yield, and Quality
Authors: Korkmaz Ahmet , Dufault Robert J.
Published: February 2019

Watermelon seedlings may be repeatedly exposed to temperatures alternating between almost freezing and optimal temperatures for growth during stand establishment in coastal South Carolina. `Carnival' watermelon transplants were exposed to 2 °C for 3, 6, and 9 h, for 1, 3, 6, and 9 days in a walk-in cooler and then to warm temperatures (24 °C) immediately prior to field planting. Our objective was to determine the long term effect of early season cold temperature exposure on seedling growth, earliness, yield and quality by simulating the cold/warm alternations possible in the field. Cold-stressed transplants were field planted after the risk of ambient cold stress was negligible. Exposure to cycling cold temperatures generally did not affect earliness, total productivity and quality, although seedling growth characteristics were reduced in response to the longer cold-stress treatment. Therefore, cold temperature stresses occurring in the field at transplanting have negligible beneficial or detrimental effects on yield potential of `Carnival' watermelon.
Effect of Hedging Interval on Yield of `Chandler' Walnuts
Authors: Kelley Kathy , Micke Warren , Ramos David E. , Yeager Jim
Published: February 2019

In many California orchards, expected yields of hedgerow plantings of `Chandler' (Juglans regia) walnuts have fallen below grower expectations. This study compared crop yields following 2-, 3-, and 4-year hedging intervals. Results indicate an incremental yield increase when `Chandler' trees are hedged on a 3-year rather than the standard alternate-year hedging rotation. Extending the hedging interval beyond 3 years shows little advantage and possible long-term negative consequences as a result of prolonged shading and loss of spurs in the interior canopy.
Effects of Nitrogen Cut-off Date in Combination with Urea or Abscisic Acid (ABA) on Terminal Bud Set, Defoliation, Cold Acclimation, and Reserve Nitrogen in `Gala' Apple Nursery Stock
Authors: Guak Sunghee , Cheng Lailiang , Fuchigami Leslie H.
Published: February 2019

Bench-grafted `Gala'/M26 apple trees were grown in pots and fertigated weekly with 150 ppm N starting from 10 May. N supply was terminated on 21 Aug., 18 Sept., and 9 Oct. for the early, mid, and late N cut-off treatment, respectively. Half of the trees in the early N cut-off treatment were sprayed twice with 3% urea at 6-day intervals in early October. Half of the trees in the mid and late N cut-off treatment were sprayed twice with 1000 ppm ABA at 5-day intervals in early and mid-October, respectively. Early N cut-off significantly enhanced terminal bud set, defoliation, and induction of cold acclimation compared to the late N cut-off. Foliar urea increased the reserve N level in all tissues of the early N cut-off trees, almost to the level of late N cut-off trees. Soluble protein concentrations were increased by foliar urea, which accounted for about 23%, 10%, and 17% of the increase in the total N concentration in bark, wood, and roots, respectively. ABA treatment enhanced leaf senescence and N mobilization in the mid and late N cut-off trees, but did not affect terminal bud set and cold hardiness.
Effect of Photoselective Plastic Films on the Growth of Bell Pepper Transplants
Authors: Li Shumin , Rajapakse Nihal C. , Young Roy E. , Oi Ryu
Published: February 2019

Removing far-red (FR) light from the greenhouse environment with liquid copper sulfate filters is an effective alternative to application of chemical growth regulators for height control of greenhouse crops. However, liquid filters have limited value in commercial operations because of handling difficulties. In this study, we report the effectiveness of photoselective plastic films that contain a FR intercepting dyestuff in controlling height of `Capistrano' bell pepper seedlings. Four types of treatment films, BCE-L (control), YCE-1 #80L, YCE-1 #75L and YCE-1 #65L, with R:FR ratios of 1.2, 1.7, 2.3 and 3.7, respectively, and one 4% liquid copper sulfate (CuSO4·5H2O) filter with R:FR of 3.5 were used as the covering materials of experimental chambers. Heights of plants grown under YCE-1 #75 or #65 films were ≈30% lower than the control plants. YCE-1 #80 film reduced plant height by ≈15%. Plant height reductions were apparent within 1 to 2 weeks after initiation of the treatments. Plants grown in YCE-1 #75, YCE-1 #65 and CuSO4 chambers had significantly lower total leaf area, leaf size, and leaf and stem dry weights than those grown in the control chamber. No differences were observed between YCE-1 #80 and control plants. No difference was found in the total chlorophyll concentration and the ratio of chlorophyll a to b between the treatment and control plants. Results imply that in peppers, a dyestuff concentration that yields a R:FR over 2 was effective in achieving over 30% height control. Although the filters with R:FR ratios higher than 2 were more effective in controlling height and producing compact pepper plants, the reduction in light intensity, or photosynthetic photon flux (PPF) by increasing dyestuff can reduce dry matter accumulation.
Case Studies in Food-borne Illnesses from Fresh Produce
Authors: Hammond Roberta
Published: February 2019

Since 1984, the State of Florida has placed additional emphasis on surveillance and investigation of food-borne illnesses. With the enhanced emphasis, several outbreaks associated with emerging pathogens and unusual vehicles have occurred. Among them are three outbreaks involving fresh produce: fresh-squeezed orange juice, fresh raspberries, and mesclun lettuce (also known as baby greens, spring greens). Florida continues to be alert to the ever-increasing possibility of outbreaks from these and other fresh produce sources. There are specific steps that occur when an outbreak of food-borne illness is identified. These involve trace-back methods, statistical comparisons, team efforts by county, state, and federal agencies, and even international agencies. This talk will cover the investigations of Salmonella in orange juice and cyclosporiasis in raspberries.
A Case Study of Salmonellosis Linked to the Consumption of Fresh-market Tomatoes and the Development of a HACCP Program
Authors: Rushing James W.
Published: February 2019

Outbreaks of salmonellosis in the United States in 1991 and 1993 were epidemiologically linked to the consumption of raw tomatoes that originated from the same fresh-market tomato packinghouse in both years. This is a case study of the response of public agencies and an industry association to a food safety crisis and the ensuring development, implementation, monitoring, and verification of a HACCP program that was proposed to serve as a model for the fresh-market tomato industry. Challenges faced by regulatory agencies in monitoring the operations of fresh-market fruit and vegetable handling facilities are discussed. Activities of an interagency food safety committee that was formed to deal with crisis management are described. The status of current research by private industry on safety related issues is briefly reviewed.
The Internet—Changing the Way Horticulturists Communicate
Authors: Rhodus Tim
Published: February 2019

Four key elements in the discipline of horticulture provide a strong incentive to use the Internet for communicating programatic information. First, a strong visual component characterizes horticultural knowledge and study. Second, the technical and practical element contained in the undergraduate curriculum, which, similar to plant identification, requires that students are presented highly visual information. Third, use of the Internet increases the efficiency and effectiveness of communicating program information and research results. Finally, the issue of content format for some applications precludes the use of any other media. Taken together, the Internet is significantly changing the environment in which horticulturists communicate.
Chemicals, Timing, and Environmental Factors Involved in Thinner Efficacy
Authors: Greene Duane W.
Published: February 2019

Chemical thinning of apples may be done over a 3- to 4-week period, starting at bloom and extending through the time fruit are 20 mm or larger in diameter. Potentially useful thinners at bloom include ammonium thiosulfate, Wilthin, endothall, and pelargonic acid. These thinners reduce set by preventing pollination, inhibiting pollen germination, or slowing pollen tube growth. Ethephon can be an effective thinner at bloom, but it is erratic. Petal fall application of thinners has become widely adopted by the industry, primarily because it reduces risks associated with one time thinner application, routinely done in the past. Carbaryl is often the thinner of choice at this time, but where more aggressive thinning is desired, NAA is used either alone or in combinations with carbaryl. Naphthale-neacetamide is effective when used at bloom but it less frequently used. Apple fruitlets are very vulnerable to the stress imposed by chemical thinners at the 8- to 12-mm stage of fruit development. NAA and Accel are particularly effective at this time, but carbaryl is frequently used because of its mild thinning action and its ability to reduce clustered spurs to one fruit. Unless weather conditions after bloom have been cool, effective thinning after the 18-mm stage of fruit development is less effective. Although erratic, ethephon is the most effective thinner on large fruit. Warm temperature during and following thinner application favor thinner uptake and response. Longer spray drying times favor thinner uptake into the plant. Environmental influences and interactions influencing thinning will be discussed.
Conducting Quality Survey Research in Horticulture
Authors: Flowers Jim
Published: February 2019

Survey research is an important methodology for many horticultural science professionals. The need to describe, validate, or determine perceptions of various aspects of the field is necessary in order to look at the “big picture” associated with the horticultural profession. When survey research is conducted, several potential errors may occur that become threats to the external validity of the research. This presentation will address the common sources of error in survey research that should be addressed by the researcher and methods used to control each source of error. While quantitative survey methodology will be emphasized in the presentation, qualitative research methodology will also be addressed.
Idiosyncrasies of Pecan Pollination
Authors: Wood Bruce W.
Published: February 2019

Pecan orchard productivity and yields often suffer due to pollination problems despite copious pollen produced within or near orchards. The problem is most acute in large block-type orchards of one or two varieties and can be due to pollen not being present at time of stigma receptivity or due to selfing. Fruit-set problems do not appear to be due to excessive pollen on stigmatic surfaces, as is the case in walnut. Pistillate flowers set best when pollen is received within about 1 day after becoming receptive. While stigma receptivity appears to lasts several days, pistillate flowers usually fail to complete development if pollinated after ≈2 days. Flowering dichogamy of given varieties varies with tree age and spring temperatures, thus often leading to poor pollination and low fruit-set. Orchards are therefore likely to benefit from the presence of two complementary pollinizers for the main crop variety. Trees in block-type orchards and are beyond about three rows or 50 m from pollinizers are likely to exhibit pollination related yield losses. Many orchards exhibit pollination problems because adherence to the standard two-class Type I/II flowering system often caused planting of noncompatible varieties. A recently developed 30-class Type I/II system allows for greater probability of avoiding pollination problems. Removal of “off-genotype” trees from orchards may reduce yields in block-type orchards.
Nutrient-Use Patterns in Nursery Crops
Authors: Rose Mary Ann , Biernacka Barbara
Published: February 2019

Long-standing fertilizer recommendations for field-grown nursery and landscape ornamentals are based on maximizing growth, not nutrient efficiency. Further, these recommendations fall short because of failure to consider 1) the extent of crop nutrient removal, 2) varying nutrient retention characteristics of soils across the United States, and 3) a body of research that suggests that woody ornamentals have a limited response to fertilization under most soil conditions. Concern for the environmental impact of fertilization justifies a reevaluation of current nursery fertilization practices, as well a discussion of the practical constraints on the adoption of new approaches, e.g., nutrient demand-driven fertilization. Research on the nutrient use patterns of woody plants will be reviewed with emphasis on implications for increasing fertilization efficiency. OSU research on water availability and nutrient-use interactions also will be presented.
The Growth of New Guinea Impatiens with Controlled-release Fertilizer in a Recirculating Subirrigation System
Authors: Richards Daphne , Reed David Wm.
Published: February 2019

New Guinea impatiens `Illusion' were grown in a recirculating subirrigation system using a controlled-release complete fertilizer (Osmocote 14–14–14). In a preliminary experiment, plants were grown under varying label rates (0, 0.5x, 1x, 2x, 4x) incorporated throughout the growing medium. Excellent growth and high-quality plants were produced at the 0.5x and 1x rates. Higher rates caused reduced growth and quality. The next study was a factorial experiment of rate (0.25x, 0.5x, 0.75x, and 1x) times placement (incorporated, top dress, bottom placement, and dibble). Slight growth increases and dramatic leaf area increases were observed with increasing fertilizer rate, regardless of placement. Slightly higher fresh and dry weights were observed in the incorporated treatment compared to the top dress treatment. Both the incorporated and top dress treatments yielded better growth than bottom placement or dibble treatments. Other parameters measured (height, chlorophyll content) did not appear to be affected by placement. EC (dS/m) of the growing medium was highest in the top 1/3 of the container in all placement treatments. EC increased with increasing rate. EC was higher in the incorporated than in the top-dress treatment, which may be due to different release rates or may be an artifact of extraction (prill removal). No rates or placements showed damaging EC levels.
Effect of C6-Volatiles on Bioluminescent Plant Pathogens
Authors: Warr Jennifer , Dane Fenny , Ebel Bob
Published: February 2019

C6 volatile compounds are known to be produced by the plant upon pathogen attack or other stress-related events. The biological activity of many of these substances is poorly understood, but some might produce signal molecules important in host–pathogen interactions. In this research we explored the possibility that lipid-derived C6 volatiles have a direct effect on bacterial plant pathogens. To this purpose we used a unique tool, a bacterium genetically engineered to bioluminesce. Light-producing genes from a fish-associated bacterium were introduced into Xanthomonas campestris pv. campestris, enabling nondestructive detection of bacteria in vitro and in the plant with special computer-assisted camera equipment. The effects of different C6 volatiles (trans-2 hexanal, trans-2 hexen-1-ol and cis-3 hexenol) on growth of bioluminescent Xanthomonas campestris were investigated. Different volatile concentrations were used. Treatment with trans-2 hexanal appeared bactericidal at low concentrations (1% and 10%), while treatments with the other volatiles were not inhibitive to bacterial growth. The implications of these results with respect to practical use of trans-2 hexanal in pathogen susceptible and resistant plants will be discussed.
Cut Flowers Being Sold as Impulse Items: A Look at Factors Affecting Impulse Product Merchandising
Authors: Neujahr Jennifer B. , Gast Karen L.B.
Published: February 2019

Consumer behavior research seems to play an big role in determining the wants and needs of an industry. This research helps to shape the way we market to the consumers and helps make marketing strategies more effective. In the 1950s grocery stores began to sell horticulture products in order to alleviate the growers' surplus. Supermarkets now have seem to found their niche in this market due to the fact that they can influence their consumers to buy their flowers right along with their bread, and get all of their shopping done at once. This new type of sale, commonly referred to as the impulse sale, can relate directly to how well the store is merchandised and maintained. A study was conducted at a local supermarket, to determine the following: good locations for impulse sales items, special conditions affecting impulse sales items, and what types of things could affect demand for impulse items. It was discovered that certain locations make better sales than other locations. Locations that were front and center and allowed easy access to seeing the mixed flower bouquet without having to touch it yielded the best results. The variables used to show a change in demand showed little to some variability and has raised some questions which may be used to conduct future research.
Freezing Tolerance and Nonstructural Carbohydrate Composition of Carpetgrass (Axonopus affinis Chase)
Authors: Bush Edward , Wilson Paul , Shepard Dennis , McCrimmon James
Published: February 2019

An experiment to determine the nonstructural carbohydrate composition and nodal survival (LT50) of common carpetgrass was conducted between 1993 and 1994 at Baton Rouge, La. Nonstructural carbohydrates in stolons were primarily sucrose [70-130 mg·g-1 dry weight (DW)] and starch (8-33 mg·g-1 DW). Total nonstructural carbohydrate (TNC) composition of stolons ranged between 30 to 165 mg·g-1 DW. Node survival following exposure to 2 °C ranged from 0% in August-sampled grass to 48% in December. The LT50 following acclimation under field conditions was -2 to -4 °C. Environmental factors influenced nonstructural carbohydrate composition, partitioning, and node survival. No relationship between TNC concentration and low-temperature tolerance was found. This research confirms previous reports that low-temperature tolerance of carpetgrass is very poor, and its culture may be limited to geographical areas having moderate winter temperatures.
002 Epidemiology of Postbloom Fuit Drop in Sweet Orange cv. Valencia in Mexico
Authors: Reyes-Gonzalez B. , Mora-Aguilera G. , Osada S. , Tèliz D. , Diaz U.
Published: February 2019

The temporal progress of postbloom fruit drop was characterized in North Veracruz, Mexico, in two commercial orchards with low and high management technology. A total of 200 flowers per orchard were assessed for disease incidence every 2 days during the flowering season. Colletotrichum isolates, putatively similar to C. acutatum, were obtained from diseased flowers and inoculated to Citrus sinensis and Citrus latifolia completing the Koch's postulates. The average Area Under Disease Progress Curve (AUDPC) (625 vs. 688 days, %) and final disease incidence (Yf) (68% vs. 67%) were statistically similar (P = 0.05) to both orchards. Epidemic rates were in the range of 0.05 to 0.16 units, with the highest variability in the high technology orchard. The total epidemic duration was 15 and 18 days for the high and low technology orchards, respectively. The highest absolute increase of disease occurred at 13 days after the beginning of flowering during the full bloom stage. The absolute increase of disease was not correlated (P = 0.05) with nonlagged values of relative humidity (%), maximum temperature (°C) and the number of Colletotrichum spores captured on a Burkard like trap. However, 5-day lagged values of spore numbers were apparently correlated with the highest absolute increase of disease. Similarly, 3- to 5-day lagged values of number of days with at least 85% relative humidity was needed to explain the main spore peaks.
005 Coir Inhibition of Soil-borne Fungal Pathogens was Not Due to Physical Properties or Biological Agents
Authors: Gaul Stephen B. , Evans Michael R.
Published: February 2019

Seedlings of Catharanthus roseus (L.) G. Don `Pacifica Red' were transplanted into substrates composed of either 80% sphagnum peat or coir with the remaining volume being perlite, sand, or vermiculite. The six substrates were inoculated with Pythium irregulare Buisman at 0 or 50,000 oospores per 10-cm container. The containers were irrigated daily to maintain moisture levels near container capacity. No visually apparent symptoms of infection or significant differences in shoot and root fresh and dry weights were observed among the uninoculated substrates and the inoculated coir substrates. Inoculated peat substrates had an 80% infection rate and significantly reduced shoot and root fresh and dry weights as compared to uninoculated substrates. Seedlings of C. roseus were transplanted into pasteurized and unpasteurized substrates composed of 80% (v/v) coir or sphagnum peat with the remaining 20% being perlite. Substrates were inoculated with 0, 5000, or 20,000 oospores of P. irregulare per 10-cm container. No visually apparent symptoms of infection or significant differences in shoot and root fresh and dry weights were observed among the uninoculated substrates and the inoculated pasteurized coir. The inoculated pasteurized peat substrate, inoculated unpasteurized peat substrate, and the inoculated unpasteurized coir substrate grown plants had an 88% infection and a significant reduction in the shoot and root fresh and dry weights.
015 Susceptibility of Atlantic White Cedar, Chamaecyparis thyoides (L.) B.S.P., to Botryosphaeria and Seiridium Cankers
Authors: Sandrock David R. , Williams-Woodward Jean , Dirr Michael A.
Published: February 2019

Five taxa of Atlantic white cedar [Chamaecyparis thyoides (L.) B.S.P.], `Blue Sport', `Okefenokee', Raulston Form, `Emily', and `Rachel', and one cultivar of Leyland cypress [×Cupressocyparis leylandii (Jacks. and Dallim.) Dallim.], `Haggerston Grey', were screened for resistance to Botryosphaeria and Seiridium cankers. Treatments consisted of Seiridium unicorne (Cke. And Ell.) Sutton, Botryodiplodia Sacc. sp., Fusicoccum Corda. sp. and the non-inoculated control. After 8 weeks, plants were measured for change in caliper at the wound site, change in plant height, and length and width of surface and interior cankers. Seiridium and Botryosphaeria canker development on Atlantic white cedar taxa was not significantly different than that on Leyland cypress. Seiridium unicorne was more pathogenic than Botryodiplodia sp. and Fusicoccum sp. on Atlantic white cedar and Leyland cypress with infection percentages of 100%, 84%, and 80%, respectively. Well-defined, sunken, resinous cankers developed on Leyland cypress plants infected with Seiridium unicorne, whereas Atlantic white cedar showed no visible surface canker.
017 Evaluating Best Management Practices for Spring Dead Spot Suppression in Bermudagrass
Authors: Iriarte F. , Fry J. , Tisserat N.
Published: February 2019

Bermudagrass turf quality is commonly reduced in the transition zone by Ophiosphaerella herpotricha, a root-infecting fungus that causes spring dead spot (SDS). Fungicides applied in autumn typically result in poor to moderate disease suppression. Earlier research has indicated that some cultural practices, including core aerification or fertilization with soil acidifying nitrogen fertilizers, may suppress SDS. Our objective was to evaluate several treatment combinations for reducing disease severity. Treatments were arranged in a split-plot design, with whole plots being aerification + verticutting, or no cultivation. Subplots within whole plots consisted of a factorial arrangement of azoxystrobin (one September application of at 0.6 kg·ha-1), trinexapac-ethyl (three summer applications at 6.1 kg·ha-1), and ammonium sulfate (three summer applications with N at 49 kg·ha-1). After 1 year of treatment, spring turf quality was improved in all treatments that included trinexapac-ethyl. Diseased area was reduced from 34% to 21% in plots receiving azoxystrobin + trinexapac-ethyl.
018 Use of Commercial Rhizobacteria for Root-knot Nematodes (Meloydogyne arenaria and M. incognita) Management in Acerola Plants
Authors: Farías-Larios J. , López-Aguirre J.G. , Miranda J.L. , Bayardo-Vizcaino L.A.
Published: February 2019

Acerola (Malpighia glabra L.) is a small, red fruit that is native to the West Indies, but is also grown in South and Central America. In western Mexico, this crop is very important because acerola is the richest known natural source of vitamin C, with a content of 1000 to 4500 mg/100 g of fruit. In nursery and field conditions, acerola growth is severely affected by root-knot nematode. The objective of this study was to evaluate the use of commercial formulations of Bacillus spp. on root-knot nematode management. This study was carried out in the Farm Santa Clara Maria in Colima State. Acerola plants, 60 days old were used. They were grown in 3-L pots with soil, compost, and pumice stone mixture as substrate. Treatments evaluated were: 5, 10, 15 and 30 mL/pot of Activate 2001, Tri-Mat (5 mL/pot) and control, without application. Activate 2001® is a concentrated liquid in water suspension of Bacillus chitinosporus, B. laterosporus, and B. licheniformis. Initial nematode population was of 3,305 in 50 g of roots. Acerola plants were harvested at 30, 60, and 90 days after application. Results show that Activate 2001 at 10 and 30 mL rates reduce significantly root-knot populations in acerola plants 60 days after application with 135 and 178 nematodes/50 g of roots, respectively. Diameter stem, shoot fresh and dry weight and root production were also increased by rhizobacteria application. These results are promising and confirmed the potential of Bacillus as a biological agent for nematode management.
032 Co-transformation with Two Vectors and Regeneration of Transgenic Plants on the Base of High-efficient Agrobacterium-mediated Gene Transfer in Grape Embryogenic Cell Suspension
Authors: Colova-Tsolova Violeta , Gollop Rachel , Farchie Sharon , Even Sylvie , Shahar Nahman , Perl Avi
Published: February 2019

Embryogenic cell suspension was developed from in vivo anthers of seedless grape cv. Sugarone. Agrobacterium genetic co-transformation was realized with two vectors carried respectively two different reporter genes: hpt and nptII, and three (1+2) agronomicaly beneficial genes encoding for proteins that are involved in fungus disease resistance. The effciency of transformation procedure and integraton of foreign genes was verified by hystochemical assay as a first step after insertion in embryogenic suspension two different constructs with Gus-reporter gene under control of different promotors. PCR assay and Southern blot analysis were used to confirm the co-transformation in regenerated grape plants.
035 Effectiveness of RAPD Markers at Distinguishing Somaclonal Variants of Strawberry Derived from Meristem Tip Culture
Authors: Hokanson Stan C. , Grant Kelvin G. , Ogden Elizabeth L. , Rowland Lisa J.
Published: February 2019

Commercial strawberry plantings in the mid-Atlantic region are often quickly infected with one or more aphid-transmitted viruses, resulting in the loss of plant vigor, stunting, lowered yields, etc. To produce virus-free plant material for the strawberry industry and for cultivar development programs, heat therapy and/or meristem tip culture protocols are generally employed. One of the problems associated with meristem culturing is the potential for somaclonal mutations to occur in the meristem or surrounding proliferating tissue. As a result, distinct “bud lines” displaying functionally insignificant to distressingly high levels of phenotypic variation can arise from individual meristems. It would be desirable to differentiate these off-types by genetic fingerprinting to maintain trueness-to-type. Randomly amplified polymorphic DNA (RAPD) markers were evaluated for the potential to differentiate six pairs of strawberry bud lines that exhibit slight to fairly extreme levels of phenotypic variation. Reproducible RAPD marker profiles were generated using 10 primers in amplification reactions with genomic DNA obtained from multiple extractions. While five of the bud line pairs remained indistinguishable, three primers distinguished two variants of the Mohawk cultivar that are now in existence in the strawberry industry. Results suggest that typical somaclonal variation produced in the meristem culture process is of a magnitude that is not readily detectable with the RAPD protocol. The two Mohawk lines were probably produced by a higher magnitude mutation event than generally occurs or a cultivar mix-up.
038 Development of SCARs for DNA Fingerprinting of Cranberry
Authors: Polashock James , Vorsa Nicholi
Published: February 2019

We have used RAPDs (Randomly Amplified Polymorphic DNAs) to successfully fingerprint cranberry. Although this method is simple and inexpensive, disadvantages include limited reproducibility in other labs and it is not easily computer-analyzed. RAPDs can also be labor-intensive because multiple primers are required to adequately fingerprint a single sample. As an alternative, we have utilized a method called SCARs (Sequence Characterized Amplified Regions). Clear polymorphic RAPD markers were cloned and sequenced. Primers were designed to amplify each polymorphic band and contained the original 10-mer RAPD primer sequence and 10 to 12 additional “clone-specific” bases. Primer sets were tested on eight common cranberry cultivars to determine if the desired polymorphic marker was amplified. The success rate of developing ëgoodí primer sets was ≈25%. The most common problem was loss of polymorphism, suggesting that selectivity was contained within the original 10-mer RAPD primer. The amplification of many similarly sized markers, suggesting the primer set amplified a repeat region, was another problem. Useful primer sets were multiplexed in PCR reactions to establish a “fingerprint.” The SCARs system we developed to fingerprint cranberry is powerful enough to distinguish individual clones in both crosses and selfed progeny. To further simply the system, computer automation for detection and analysis using fluorescently labeled primers is underway. One problem we are addressing is reduced product in the labeled multiplex reactions. Reduced product yield is presumably because the dye molecule (Cy5) is very large and may reduce primer binding and/or polymerization efficiency. This problem has been somewhat alleviated using a patented form of Taq DNA polymerase.
050 Comparative Analysis of Cultivated Melon Groups (Cucumis melo L.) using Random Amplified Polymorphic DNA and Simple Sequence Repeat Markers
Authors: Staub Jack E. , Fazio Gennaro , Horejsi Thomas , Danin-Poleg Yael , Reis Noa , Katzir Nurit
Published: February 2019

Random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) markers were used to characterize genetic relationships among 46 accessions in two C. melo L. subsp. melo (Cantalupensis, Inodorus) and subsp. agrestis (Conomon and Flexuosus) groups. Genetic distance (GD) estimates were made among and between accessions in four melon market classes [Galia, Ogen, Charentais, and Shipper (European and U.S. types)] of Cantalupensis, one market class of Inodorus (Cassaba and Honey Dew), one accession of Conomon, and one accession of Flexuosus by employing three GD estimators; simple matching coefficient, Jaccard's coefficient, and Nei's distance-D. Differences detected among 135 RAPD bands and 54 SSR bands (products of 17 SSR primers) were used to calculate GD. Band polymorphisms observed with 21 RAPD primers and 7 SSR primers was important in the detection of genetic differences. Estimators of GD were highly correlated (P > 0.0001; rs = 0.64 to 0.99) when comparisons were made between estimation methods within a particular marker system. Lower correlations (P > 0.001; rs = 0.17 to 0.40) were detected between marker systems using any one estimator. The GD of the Conomon and Flexuosus accessions was significantly different from the mean GD of all the market classes examined, and market classes were distinguishable from each other. Although lower coefficients of variation can be attained in the estimation of GD when using RAPDs compared to SSRs, the genetic relationships identified using these markers were generally similar. Results of RAPD marker analysis suggest that 80 marker bands were adequate for assessing the genetic variation present in the accessions examined.
055 Transformation of Chinese Cabbage Glutathione Reductase (GR) Gene into Lettuce (Lactuca sativa L.) with Microparticle Bombardment
Authors: Chung J.D. , Lee B.J. , Lee H.S. , Kim C.K.
Published: February 2019

Lettuce (Lactuca sativa L.) were transformed using microparticle bombardment with two different genes, alpha-glucuronidase (GUS) gene and Chinese cabbage Glutathione Reductase (GR) gene. The adventitious shoots of cotyledonary explant from 4-day-old seedlings were formed (46.7%) in MS basal media supplemented with 5.0 μm IAA and 1.0 μm 2ip. When 1100 psi helium pressure, 9 target distance, and coating with tungsten 10 microparticles were used and explants were treated with osmoticum-conditioning medium (0.6M sorbitol/mannitol), 4 h prior to and 16 h after bombardment, it was identified by GUS assay that these conditions were the most efficient for transformation of foreign genes into cotyledon tissue of lettuce with particle bombardment. PCR confirmed that the band observed in the transgenic plants were originated from T-DNA tranfer with strong hybridization. The genomic Southern analysis showed that the 1.5-kbp fragment was hybridized with radiolabeled 1.5-kbp GR probe. To know whether the expression of the GR gene can be stably maintained in the next generation, when T2 selfing seeds that were obtained from the transformed mother plants were sowed on MS medium supplemented with 200 μm kanamycin, 70% of seedlings were revealed resistance to kanamycin.
061 Examining the Phaseolus coccineus Collection for White Mold Resistance
Authors: Gilmore Barbara , Myers James R.
Published: February 2019

White mold, (Sclerotinia sclerotiorum), is an aggressive pathogen of beans and is capable of inflicting devastating damage on yield. Finding resistance is a major concern to bean breeders. The scarlet runner bean (Phaseolus coccineus) is generally known to have greater resistance to white mold than does the common bean, (P. vulgaris). Since it is possible to cross these two species, we have started to examine the NPGS core collection of P. coccineus for resistance to this pathogen. A straw test was used to measure physiological resistance of bean stems to white mold. A rating of one equates to a small lesion, resulting from contact with inoculum, and a rating of nine describes total plant collapse. Controls that were used were two common beans, 91G, a commercially produced, blue lake type snap bean and ExRico, a small, white dry bean. The bean 91G received a straw test rating of 8.3, which correlates to a field test rating of 8.5. ExRico rated 7.4 with the straw test and had a field test score of 6.5. Within the P. coccineus collection we found very strong resistance, with straw test values of 1 and 2 in several individual plants and in some accessions. Accessions that had individuals that displayed the strongest resistance of all the plants tested were: PI201299, PI361302, PI406938, and PI535278. These accessions appeared to be segregating for white mold resistance. Accessions showing the best average resistance were: PI313221, PI361372, PI361539, and PI583553. Because P. coccineus is outcrossed, we expected to find variation within accessions for white mold resistance. Some accessions had uniformly high levels of resistance, while other accessions showed variability.
064 Sugars in Tropical-type Sweetpotato
Authors: Hernández-Carrión Tania , Ortiz Carlos E. , Montalvo-Zapata Rafael , Mercado-Olivieri Milca I. , Rivera Luis E.
Published: February 2019

Tropical-type is a general description for sweetpotato cultivars with intermediate sweetness that have light-fleshed roots. This type is commonly grown and consumed across the Caribbean Basin. Systematic efforts for the genetic improvement of the tropical-type sweetpotato have been limited. Cultivars available for being grown in Puerto Rico lack either the sweetness or attractiveness demanded by producers and consumers. Defining optimum sweetness in this type is important because this characteristic is totally dependent on the root's sugar content and cannot be modified as in processed products. The objective was to obtain data on sugar content for the development of quantitative selection criteria for sweetness. Raw, boiled and baked roots were evaluated for glucose, sucrose, fructose, and maltose. `Mina' and `Miguela', tropical-type cultivars widely accepted for sweetness and table quality but poor yielders were used. `Viola', a substaple type, was the check. Sugars were detected by HPLC. Sugar-Pak (Waters) and LC-NH2 (Phenomenex) columns and a refractive index detector were used for the analyses. Across cultivars and type, sucrose (4.0% to 6.5%) was more concentrated than glucose (0.4% to 0.8%) and fructose (0.3% to 0.4%). Concentration of sucrose in the tropical type (7.7%) was higher than in the substaple type check (4.4%). Boiling or baking did not markedly change the concentration of the above sugars. Maltose was not detected in raw samples; however, both boiling and baking increased maltose concentration from 9.0% to 15.4%. In the development of a practical quantitative selection criteria for sweetness, both sucrose and maltose must be considered.
069 Preservation of Lettuce Seed for 30 Years: Cryopreservation Retarded Deterioration
Authors: Stanwood P.C. , Wheeler L. , Towill L.E.
Published: February 2019

Long-term preservation of seed germplasm is a high agricultural priority. It assures that genetic diversity will be available for future generations for continued plant improvement. This experiment reports on the affect that storage temperature had on the viability of 65 selections of lettuce seed stored for 30 years. The average seed moisture content was 5.5% ± 0.5% (fresh weight basis). Fresh seed samples were placed at 5 °C storage in 1969. In 1975 they were then transferred to -18 °C storage. Viability remained at 98% ± 5% for the first 14 years of 5 /-18 °C storage, then viability declined. At 17 years storage, the average viability had dropped to 75% and continued to drop at about 4%/year. At the 17-year mark, individual samples were split, one-half remained at -18 °C the other half was placed under liquid nitrogen vapor (lnv) conditions (about -150 to -190 °C). The -18 °C stored samples continued to deteriorate to 14% viability at the 30 year test period (1999). The samples placed in lnv did not decrease further in viability and remained at 75% viability at the 30-year mark. Seed vigor was reduced in the -18 °C stored seeds that were still viable. The lnv-preserved samples were significantly more vigorous. It is clear from this experiment that lnv preservation was significantly superior to -18 °C storage and, in fact, stopped or significantly reduced the rate of viability loss in samples that are rapidly deteriorating.
074 The Effects of Leaching and Stratification Media on Rosa spp.
Authors: Anderson Natalie , Byrne David H.
Published: February 2019

Poor germination in Rosa spp. has hindered breeding programs for years. Several methods exist to increase germination of rose seed. Unfortunately no consensus exists on the best method, or if any one method is best for all rose types. Rose seeds from a R. wichuraiana × Old Blush hybrid were broken into 3 replications with an average of 400 seeds per replication. Seeds were leached at room temperature with tap water for a period of 0, 3, 7, or 14 days. Constant filtration and aeration were supplied. After leaching, seeds were placed on either moist milled sphagnum moss or agar. Seeds were then placed in a cold stratification (≈2.8 °C) treatment for 8 to 12 weeks. Individual seedlings were planted when a root was visible. The combination of no leaching plus the moist milled sphagnum moss treatment significantly increased germination over leaching for 3 or more days and agar.
075 Effects of Temperature during Germination on the Germination and Survival of Embryo Cultured Peach Seed
Authors: Byrne David H. , Anderson Natalie , Sinclair Jonathan , Burrell A. Millie
Published: February 2019

Embryo culture techniques are employed in early ripening peach and nectarine cultivars. Generally, the embryos in these varieties are not mature by the time the fruit matures, thus rendering normal stratification procedures ineffective. In 1998 and 1999, immature embryos from multiple peach genotypes were cultured in an embryo rescue media (WPM, 3% Sucrose) at 5 °C for 45 days in the dark. Embryos were then placed under lights at either a cool temperature (18 °C in 1999 and 20 °C in 1998) or a warm temperature (30 °C in 1999 and 28 °C in 1998) treatment with a photoperiod of 12 h for germination and initial growth. After 2 to 4 weeks embryos were rated for germination, root number, and top growth. The embryos incubated at the cool temperature regime not only had better germination, but also had a higher rate of greenhouse survival.
081 New Hardy Apple Selections from the Québec Apple Breeding Program
Authors: Khanizadeh S. , Groleau Y. , DeEll J.R. , Cousineau J. , Granger R. , Rousselle G.
Published: February 2019

The objectives of the Québec apple breeding program are to develop hardy and disease-resistant varieties for the production of juice and cider and/or varieties with an excellent fruit quality and long shelf-life. Almost 90% of the research in apple breeding is funded by a Partnership Program, in which the partners cover ≈50% of the research costs. The short-term objectives of the program are to evaluate the existing genotypes at the AAFC Frelighsburg sub-station and name worthy selections, remove unworthy material, and transfer potentially interesting genotypes to other AAFC research stations for further evaluations. Three selections—SJC7713-1, SJC686-1, and O-5410—are very hardy, scab-resistant, and have good yields of pleasantly flavored fruit, which can be stored long-term while retaining good quality. Selections SJCA14R3A108 and SJCA36R7A87 are not scab-resistant, but they are hardy, and the fruit have an excellent flavor, store very well for >5 months, and have a flesh that does not darken after cutting. The above selections are currently being evaluated for use by commercial growers. Selections SJC7172-1 and SJC7911-1, along with four crabapple genotypes, are of potential interest to home gardeners.
091 Feeding Preferences of Black-margined Pecan Aphids
Authors: Reid William
Published: February 2019

Field resistance to the black-margined pecan aphid [Monellia caryella (Fitch)] was evaluated for 12 pecan [Carya illinoinensis (Wangen.) K. Koch.] cultivars in 1995 and 19 cultivars in 1999. Each year, aphid populations were sampled from four trees of each cultivar by counting the number of aphids on 10 mid-shoot leaves per tree each week throughout the growing season. On leaves of several cultivars, populations of black-margined aphids peaked above the economic threashold level (20 aphids/leaf) during the month of August in both years. `Pawnee' and `Greenriver' demonstrated field resistance to aphids by maintaining fewer than 10 aphids/leaf throughout the season. `Hirschi' and `Posey' maintained among the highest aphid populations in both years—2 to 5 times higher than threashold levels. By avoiding cultivars susceptible to aphid feeding, growers can avoid aphid-induced yield reductions.
100 Microbial Evaluation of Electrolyzed Water Treated Fresh-cut Carrots in CA/MA Storage
Authors: Izumi Hidemi , Suzuki Akihiro
Published: February 2019

The effect of electrolyzed water on bacterial count was evaluated on CA/MA stored carrot shreds. Electrolyzed water (pH 6.8) containing 50 ppm available chlorine, was generated by electrolysis of 2.5% NaCl solution using an electrolyzed neutral water generator, Ameni Clean (Matsushita Seiko, Osaka, Japan). Electrolyzed water treatment reduced counts of total bacteria and lactic acid bacteria on surface of carrot shreds by about 1 log CFU/g as compared to water-rinsed control. Microbial population increased on treated carrot shreds stored in air or 3% O2 atmosphere at 10 or 20 °C. The increasing count of lactic acid bacteria was less on electrolyzed water treated samples than on control samples during storage at 10 °C. Electrolyzed water did not affect respiration rate of carrot shreds during storage at 10 and 20 °C. For MA study, the treated carrot shreds were packaged and stored in a polymeric film in which the O2 and CO2 concentrations equilibrated to about 10% and 3% at 10 °C and about 6% and 7% at 20 °C, respectively. The lactic acid bacterial count on shreds in MAP was lower with electrolyzed water treated samples than water treated controls during storage at 10 and 20 °C.
103 Tomato Cultivation using Black Polyethylene or Hairy Vetch Mulches and Various Foliar Disease Management Systems: Effect on Subsequent Quality of Fresh-cut Slices
Authors: Hong Ji Heun , Mills Douglas J. , Coffman C. Benjamin , Anderson James D. , Camp Mary J. , Gross Kenneth C.
Published: February 2019

Experiments were conducted to compare changes in quality of slices of red tomato (Lycopersicon esculentum Mill., cv. Sunbeam) fruit from plants grown using black polyethylene or hairy vetch mulches under various foliar disease management systems including: no fungicide applications (NF), a disease forecasting model (Tom-Cast), and weekly fungicide applications (WF), during storage at 5 °C under a modified atmosphere. In this study, we used the fourth uniform slice from the stem end and analyzed for firmness, soluble solids content (SSC), titratable acidity (TA), pH, electrolyte leakage, molds, yeasts and occurrence of water-soaked areas. With both NF and Tom-Cast fungicide treatments, slices from tomato fruit grown with hairy vetch mulch showed greater firmness than those from tomato fruit grown with black polyethylene mulch after 12 d of storage. Ethylene production of slices from tomato fruit grown using hairy vetch mulch under Tom-Cast was about 1.5- and 5-fold higher than that of slices from tomato fruit grown under the WF and NF fungicide treatments after 12 d, respectively. Within each fungicide treatment, slices from tomato fruit grown using hairy vetch mulch showed less chilling injury (water-soaked areas) than those from tomatoes grown using black polyethylene mulch. The percentage of water-soaked areas for slices from tomato fruit grown using black polyethylene mulch under NF was over 7-fold that of slices from tomato fruit grown using hairy vetch under Tom-Cast. These results suggest that, under our conditions, fruit from plants grown using hairy vetch mulch may be more suitable for fresh-cut slices than those grown using black polyethylene mulch.