bluuebunny/crossref_metadata_2025 huggingface dataset:
658 Engineering Ethylene Synthesis and Perception for Fun and Profit
Authors: Klee Harry
Published: February 2019

Ethylene-based technologies for controlling ripening in climacteric fruit have been in widespread use for a number of years. Likewise, using chemicals that block ethylene synthesis or perception have been widely used to extend shelf life of a variety of horticultural commodities. In the last few years, our understanding of the molecular mechanisms for ethylene synthesis and perception has greatly expanded. Genes encoding the ethylene biosynthetic enzymes and the ethylene receptor have been cloned from many plant species, which has meant that molecular approaches to engineering reduced ethylene synthesis or perception are now reality. Scientists have been examining the feasibility of using molecular approaches to control ethylene in a variety of horticultural and ornamental species. They have shown that it is relatively easy to produce plants that are reduced in either synthesis or response to ethylene. However, scientists have uncovered some issues associated with commercial-level use of these transgenic plants. Overall, my results illustrate the great potential of the technology to control the rate of climacteric fruit ripening, abscission, and ethylene-induced senescence in multiple species, but using transgenes in many cases needs to be directed to target tissues through the use of tissue-specific transcriptional promoters. With that caveat in mind, there should be a strong future for improving the quality of a range of agronomic and horticultural species.
662 Molecular Mechanisms and Potential Control of Abscission in Horticultural Crops
Authors: Burns J.K. , Arias C. , Kostenyuk I. , Obraztnova M.
Published: February 2019

The process of abscission results in shedding of plant parts such as leaves, fruit, flowers, and in citrus, shoot tips and entire shoots. Growers must successfully manage abscission in their operations to avoid unnecessary defoliation or loss of yield due to floral abscission or preharvest fruit drop. Conversely, abscission enhancement may be desired during harvest. Yet despite its importance to horticulture, little is known about mechanisms that control abscission. We know that abscission can be induced by ethylene and altered to some extent by auxin. Over the years, many physiological and anatomical events of abscission have been described. For example, cellulase, polygalacturonase and pectin methylesterase genes are induced during abscission, and they are thought to have a role in alteration and depolymerization of middle lamella polysaccharides located in the abscission zone area. Other genes, such as those associated with the process of pathogen resistance, are also induced during abscission. We are interested in using tools of molecular biology to examine abscission-related gene expression prior to organ separation in Florida field-grown Valencia orange (Citrus sinensis L. Osbeck) and greenhouse-grown calamondin (Citrus madurensis Loureiro) citrus trees. Subtractive cDNA library screening and differential display were used to examine gene expression in fruit, leaf and floral abscission zones 6, 24 and 48 h after induction of abscission with 5-chloro-3-methyl-4-nitro-1H-pyrazole or Ethrel® (Rhone-Poulenc, [2-chloroethyl] phosphoric acid). Some isolated cDNAs encoded polypeptides with no significant matches in the database or share significant similarities with unknown proteins isolated from Arabidopsis. Other cDNAs encoded polypeptides with similarity to cell wall modifying proteins such as polygalacturonases and expansin, PR proteins such as chitinase, proteins associated with secondary and xenobiotic metabolism such as amine oxidase, benzoquinone reductase, caffeic acid methyltransferase, phenylalanine ammonia lyase and squalene synthase, and proteins associated with signal transduction such as several serine/threonine kinases. Temporal and spatial expression of these genes and others will be presented. Use of this information to target potential points of abscission control will be discussed.
665 Opportunities in Using Biotechnology to Maintain Postharvest Quality and Safety of Fresh Produce
Authors: Kader Adel A.
Published: February 2019

Biological factors involved in deterioration of fresh horticultural perishables include respiration rate; ethylene production and action; compositional changes associated with color, texture, flavor (taste and aroma), and nutritional quality; growth and development; transpiration; physiological breakdown; physical damage; and pathological breakdown. There are many opportunities to modify these inherent factors and to develop genotypes that have lower respiration and ethylene production rates, less sensitivity to ethylene, slower softening rate, improved flavor quality, enhanced nutritional quality (vitamins, minerals, dietary fiber, and phytonutrients including carotenoids and polyphenols), reduced browning potential, decreased susceptibility to chilling injury, and increased resistance to postharvest decay-causing pathogens. In some cases the goals may be contradictory, such as lowering phenolic content and activities of phenylalanine ammonialyase and/or polyphenoloxidase to reduce browning potential vs. increasing polyphenols as antioxidants with positive effects on human health. Another example is reducing ethylene production vs. increasing flavor volatiles production in fruits. Overall, priority should be given to attaining and maintaining good flavor and nutritional quality to meet consumer demands. Extension of postharvest life should be based on flavor and texture rather than appearance only. Introducing resistance to physiological disorders and/or decay-causing pathogens will reduce the use of postharvest fungicides and other chemicals by the produce industry. Changes in surface structure of some commodities can help in reducing microbial contamination, which is a very important safety factor. It is not likely that biotechnology-based changes in fresh flowers, fruits, and vegetables will lessen the importance of careful and expedited handling, proper temperature and relative humidity maintenance, and effective sanitation procedures throughout the postharvest handling system.
675 Horticultural Factors Affecting Anthocyanin and Phenolic Content and Antioxidant Capacity of Small Fruit
Authors: Kalt W. , McDonald J.E. , MacKinnon S.
Published: February 2019

Fruit and vegetable components that possess antioxidant capacity are being actively investigated because of the purported impact of dietary antioxidants on human health. Phenolic components, including anthocyanins, are believed to be major contributors to the antioxidant capacity of many small fruit species. Various horticultural factors have been examined with respect to anthocyanin and phenolic content, and antioxidant capacity of small fruit, especially Vaccinium species. Vaccinium species, and certain other fruits, had a high antioxidant capacity compared to strawberries and raspberries. However, genotypic variation in these characteristics was substantial among wild blueberry clones. Fruit maturity did not influence antioxidant capacity, although phenolic profiles changed dramatically during ripening. Fresh storage of certain ripe fruit at 20 °C led to increased anthocyanin content and increased antioxidant capacity. Certain food processing factors, such as heat and oxygen, decreased the antioxidant capacity of blueberry products.
679 Freelance Consulting in Tropical Agriculture
Authors: Campbell Carl W.
Published: February 2019

During a 30-year career of research, extension, and teaching in tropical fruit production, I participated frequently in international agricultural activities in countries of Central America, South America, and the Caribbean region. In 1988, I retired from the Univ. of Florida to begin a “second career” as a freelance consultant in tropical fruit production and crop diversification, working for a variety of governmental and private organizations. This presentation contains suggestions for horticultural scientists who wish to become involved in consulting in international agriculture. First, decide the kind of work you wish to do and what your area of specialization will be. Choose work for which you have enthusiasm. Get training in basic as well as applied science. It is good to have a “day job,” at least at first, as you establish a reputation in your specialty. Become proficient in the languages of the regions where you wish to work; also carefully study the cultures. When you participate in an international project, work hard and prepare good reports of your accomplishments. As your career progresses, consider carefully whether or not you will become a full-time consultant. It is a demanding way to make a living, but it can also give much satisfaction and greater independence than one finds in many other kinds of work.
680 Innovative Methods to Market Locally Grown Products
Authors: Uva Wen-fei L.
Published: February 2019

The development of industrialized production and global sourcing has changed the marketing structure of the horticulture industry dramatically. The inherent disadvantaged resource base (soils and climate) and high production costs in the northeast United States make it difficult for growers to compete in commodity markets. Exploiting niche and value-added markets are important for the survival of northeast agriculture. Moreover, an emphasis on quality of life has created a movement towards sustainable agriculture. As a result of this movement, many programs have been initiated to promote locally grown products and to support agricultural-based economic development. The common objectives of the “locally grown” programs are to promote agricultural products produced within the region, support the local economy, and develop agricultural markets. Keys to success of a “locally grown” program are a vision, seed funding, a champion, and community, political leadership and technical support. Many innovative regional food and agriculture development programs have been initiated in New York State to support local farmers, revitalize the rural economy, promote local identity and pride, develop agri-tourism, and capture the urban markets. Some examples include the “Finger Lakes Culinary Bounty” initiated by local chefs, “Uncork New York” sponsored by the wine industry, and “Hudson Valley Harvest” and a pilot ethnic market project targeting New York City markets.
681 Controlling Stress in Container-grown Plants
Authors: Buxton Jack W.
Published: February 2019

The controlled water table irrigation system (CWT) consists of a capillary mat placed on a level bench so one side extends over the edge of the bench into a trough containing a nutrient solution maintained at a controlled distance below the bench. The nutrient solution is drawn by capillarity up to and over the bench surface. As plants use the nutrient solution or as water evaporates from the media, it is replaced from the trough. The automatic system maintains a constant air/water ratio in the growing media. Study 1: Geraniums were grown in 15-cm pots at 0, 2, and 4 cm CWT. Geraniums at 0 and 2 cm CWT had the greatest leaf area and dry weight. Plants at 0 and 2 cm CWT were more than 25% greater at 4 cm CWT. The roots of plants at 0 cm CWT were concentrated at 2 to 4 cm above the bottom of the container; whereas roots at 2 cm CWT uniformly extended from the center to the bottom. Study 2: Water potential in a coarse and fine textured media was determined at the bottom, middle and top of the container at 0, 2, and 4 cm CWT every 2.5 h during the light period. Water potential was about the same in each media within each CWT treatment. At the container bottom at 0 CWT water potential was 0; whereas the water potential at 2 and 4 CWT was lower. The water potential from top to bottom decreased slightly about mid afternoon on a sunny day when water demand was the greatest. The CWT system is potentially a commercially adaptable irrigation system for container crops. It also is a cheap, reliable tool for studying water stress on the crop growth and quality.
686 Using an Agroecosystem Approach in Systems Research
Authors: Delate Kathleen
Published: February 2019

Because cropping systems must fit into the environmental, social, cultural and economic reality of the farming community, it is essential that practitioners are included in designing experimental techniques and evaluating application for their farms. Iowa State Univ. conducted a series of Focus Groups with growers and agribusiness professionals to assist in the design of vegetable cropping systems research trials. Trials were established to investigate vegetable agroecosystem status and needs. An agroecosystem analysis seeks to identify indicators of sustainability in a system, including plant health, biological diversity, soil/water quality, and level of biological control of insects and diseases. From this work, a checklist of ecological parameters has been developed for use in cropping systems research. Examples from Iowa, California, and North Carolina will be presented as case studies, exploring multi-disciplinary approaches to cropping systems research.
687 Implementation of Long-term Farming Systems Studies: Challenges and Opportunities
Authors: Creamer N.G. , Mueller J.P.
Published: February 2019

The Center for Environmental Farming Systems (CEFS) is dedicated to developing farming systems that are environmentally, economically, and socially sustainable. Established in 1994 at the North Carolina Dept. of Agriculture Cherry Farm near Goldsboro, CEFS has >2000 acres (1000 cleared). This unique center is a partnership among North Carolina State Univ., North Carolina Agriculture and Technical State Univ., North Carolina Dep. of Agriculture and Consumer Services, nongovernmental organizations, and other state and federal agencies, farmers, and citizens. Long-term cropping systems that integrate the broad range of factors involved in agricultural systems is the focus of the Cropping Systems Unit at CEFS. The USDA SARE program has provided funding to help establish a comprehensive long-term, large-scale experiment. Data collection and analyses include comprehensive soil and water quality, pests and predators (weeds, insects, and disease), crop factors (growth, yield, and quality), economic factors (viability, on/off farm impact, and community), and energy issues. Systems being compared are a successional ecosystem, plantation forestry/wood lot, integrated crop/animal production system, organic production system, and a cash-grain cropping system (BMP). An interdisciplinary team of scientists from almost every department from the College of Agriculture and Life Sciences, along with faculty from North Carolina Agriculture and Technical State Univ., NGO representatives, and farmers are collaborating in this endeavor. Challenges and opportunities in building collaborative teams and setting up such long-term trials will be discussed.
688 New PGRs: High Risk Investment?
Authors: Rademacher Wilhelm , Bucci Toni
Published: February 2019

Plant growth regulators (PGRs) account for only a few percent of the worldwide sales of crop protectants. In recent years, most companies have drastically reduced their activities in the PGR area. The factors that have been of major relevance in this development are: a) Finding, developing and marketing a new PGR is more difficult and requires a considerably higher input as compared to other types of crop protectants, b) many segments of the market are fairly saturated with competitively priced products, and c) intensified legislation for the registration of new, and the re-registration of established products, has become a severe constraint, due to its absorbing large working and financial capacities. For these and other reasons, new types of PGRs will be economically viable only under certain circumstances, such as: a) A sufficiently large and profitable market guarantees a reasonable return on investment, b) costs for registration can be reduced by developing naturally occurring compounds, which may require considerably less toxicological and eco-toxicological studies, and c) PGR-like side activities of an existing herbicide, fungicide or insecticide can be exploited, which would, again, significantly reduce the costs for registration.
691 Obtaining Shoot Explants From Softwood Shoots Forced From Large Stem Segments of Woody Plants
Authors: Preece John E.
Published: February 2019

Softwood shoots can be forced from sections of branches of trees or from basal stems of shrubs by cutting into ≈40-cm lengths and placing these segments horizontally in flats filled with perlite. We have had our best success using stems that are >1.5 cm in diameter. Although the best environment that we have found for producing the most and longest softwood shoots is under intermittent mist, this is unacceptable for producing explants because of microbial contamination. Rather, for micropropagation, watering must be done two to three times a day and care must be taken to avoid water spray onto the stem segments or the subsequent softwood growth. Irrigation can be by hand or by using drip irrigation. For trees, using the basal portions of large branches allows for selection of shoots from within the “cone of juvenility.” Theoretically, these should propagate better than shoots taken from the outer, more adult portions. Although late winter through spring are the best times for forcing, some shoots will grow if the stem sections are harvested nearly any time of the year, except for October through December in southern Illinois.
694 Evaluation of Low-rate Herbicides for Minor Crops
Authors: McGiffen Milton E. , Fennimore Steven A. , Lanini W. Thomas , Bell Carl E.
Published: February 2019

The Food Quality Protection Act may result in the withdrawal from use of many herbicides in the “minor” crops: fruits, vegetables, herbs, flowers, and ornamentals. An obvious mitigation strategy is to test and register newer, low-rate herbicides that are currently used only in large-acreage field crops. The newer herbicides have low mammalian toxicity, few off-target effects, and are often used at rates of less than 0.1 kg/ha. Many of the older herbicides are applied at rates of several kg/ha and have off-target effects that can make their use problematic. Low-rate herbicides could replace the older chemicals commonly used in horticultural crops. We have tested several promising low-rate herbicides: carfentrazone, cloransulam, dimethenamid, halosulfuron, rimsulfuron, and sulfentrazone. Broccoli, cantaloupe, carrot, lettuce, onion, spinach, and processing tomato varieties were screened for tolerance to low-rate herbicides at four locations in California that included desert, inland, and coastal environments. All of the crops tested had tolerance for one or more of the low-rate herbicides. Data on similar tests for other horticultural crops will also be presented. The potential for registering these herbicides in vegetables and other horticultural crops varies with the crop and the pesticide's manufacturer. Pesticides that may soon face removal from widespread use will be reviewed. Herbicides and other potential alternatives to currently registered herbicides will be examined to determine possible practical alternatives for specific crops and weeds.
Evaluation of Chilling Requirement of Southern Blackberry Cultivars
Authors: Drake Chrislyn A. , Clark John R.
Published: February 2019

Little research has been done to determine the chilling requirement for southern blackberry cultivars. However, field observations from areas where low amounts of chilling occur indicate that `Navaho' requires more hours of chilling than does `Arapaho'. The objective of the study was to determine a method for measuring chilling requirement using whole plants of two blackberry cultivars, Arapaho and Navaho. One-year-old bare-root plants of `Arapaho' and `Navaho' were field-dug and placed in a cold chamber at 3 °C. Ten single-plant replications of each cultivar were removed at 100-hour intervals up to 1000 hours. The plants were then potted and placed in a greenhouse (daily minimum temperature 15 °C) in a completely randomized design. Budbreak was recorded on a weekly basis. Data for budbreak was analyzed as a two-factor factorial (two cultivars and 10 chilling treatments) by SAS and means separated by lsd (P = 0.05). Data indicated that the chilling requirement for `Arapaho' is between 400 and 500 hours. This is evident as a 6-fold increase, which was the largest increase between two chilling treatments, occurred between 400 and 500 hours. For `Navaho', the largest increase (also 6-fold) occurred between 800 and 900 hours, which indicated a chilling requirement for `Navaho' of 800 to 900 hours. These data support previous observations and indicate the method used was successful in determining chilling requirement for blackberries.
Members of the Family Leporidae Can Select for Onions with High Soluble Sugars and Low Pyruvates
Authors: Neal Melissa , Peffley Ellen B.
Published: February 2019

Over the past several growing seasons researchers at Texas Tech University have observed that certain onions appeal to rabbits more than other onions, meaning that rabbits tend to nibble on certain lines or varieties and leave other lines undisturbed. We were interested in determining the cahracteristics of the onions that rabbits seemed to like. Onions were planted at random in the TTU breeding nursery. During the growing season all onions were rated for rabbit appeal - those with chewed leaves and or bulbs were recorded as liked by the rabbits. All onions in each plot, whether disturbed or undisturbed by the rabbits, were tested for pyruvate concentration and soluble solids content after harvest. Pyruvates were measured by mmol/gram pyruvic acid and soluble solids content by °Brix refractometer reading. The most damage occurred in onion lines that had the lowest pyruvate levels. Soluble solids did not appear to affect the rabbits' nibbling.
The Effects of Heat Stress on Photosynthesis of Coreopsis grandiflora `Sunray' and Gaillardia ×grandiflora `Goblin'
Authors: Davis Melyssa K. , Kuehny Jeff S.
Published: February 2019

Herbaceous perennials are one of the fastest growing ornamental sectors in the United States. Current production recommendations do not address the effect of environmental factors, such as high temperature, on growth of herbaceous perennials. The focus of this research was to determine how supra-optimal temperatures effect growth and photosynthesis. Plants were exposed to a high temperature of 35 °C and photosynthesis measurements were recorded over a 6-week period at 1100, 1300, and 1500 hr. Results indicate that the time of day the measurements were taken made little difference on rate of photosynthesis and that there was a similar trend in photosynthetic rate over the 6-week period. Photosynthesis decreased as the plants began to flower and then increased until the onset of flower senescence. Plants grown at supraoptimal and optimal conditions had a similar trend and rate of photosynthesis throughout the 6-week period. Plant growth significantly decreased as the duration of high temperature increased for both species; however, Gaillardia was more heat tolerant then Coreopsis.
Genetic Diversity in Papua New Guinea Sweetpotato Germplasm
Authors: Fajardo Diego , La Bonte Don R. , Jarret Robert L.
Published: February 2019

The USDA gene bank currently maintains 668 accessions of cultivated sweetpotato and 219 accessions of related Ipomoea species. Information on the genetic diversity of the collection does not exist due to funding constraints. The development of a core collection would provide a subset of accessions that represent the genetic diversity of the main collection with a minimum of repetitiveness. The small size of the core collection would facilitate the evaluation of the accessions for economically important traits. The objective of this research is to develop a core collection of Papua New Guinea sweetpotato germplasm using the Amplified Fragment Length Polymorphisms (AFLPs) marker system. This approach to quantifying genetic diversity would later serve as a model for the development of a USDA sweetpotato germplasm core collection. The germplasm choosen for this study was collected from this crop's secondary center of genetic diversity based on its potential as a source of new traits. All genotypes were fingerprinted using four primer combinations that generated 224 markers. The molecular data was then analyzed using NTSYSpc 2.0 program to determine the relatedness of the genotypes. The molecular analysis showed a homogeneous genetic constitution. The extent of diversity among accessions was correlated with the geographic origin of the plant material.
Identification of Molecular Markers that Segregate in a Simple Mendelian Fashion in a Controlled Cross of Asimina triloba
Authors: Bonney Tera M. , Brown Shawn P. , Jones Snake C. , Pomper Kirk W. , Geneve Robert L.
Published: February 2019

The pawpaw [Asimina triloba (L.) Dunal] is a native plant found mainly in the southeastern and eastern United States, and its fruit has great potential as a new high-value crop in these regions. Although there are ≈45 named pawpaw cultivars, breeding for improvement of specific traits, such as fruit size and quality, is desirable. Our long-term goal is to utilize molecular marker systems to identify markers that can be used for germplasm diversity analyses and for the construction of a molecular genetic map, where markers are correlated with desirable pawpaw traits. The objective of this study was to identify random amplified polymorphic DNA (RAPD) markers that segregate in a simple Mendelian fashion in a controlled A. triloba cross. DNA was extracted from young leaves collected from field-planted parents and 20 progeny of the cross 1-7 × 2-54. The DNA extraction method used gave acceptable yields of ≈7 μg·g-1 of leaf tissue. Additionally, sample 260/280 ratios were ≈1.4, which indicated that the DNA was of high enough purity to be subjected to the RAPD methodology. Screening of 10-base oligonucleotide RAPD primers with template DNA from the parents and progeny of the cross has begun. We have identified two markers using Operon primer B-07 at 1.1 and 0.9 kb that segregate in a simple Mendelian fashion in progeny of the 1-7 × 2-54 cross. Other primers and controlled crosses will also be screened.
Imbibition Rates in Film-coated Shrunken-2 Sweet Corn (Zea mays) Seeds
Authors: Wilson Tina , Geneve Robert , Rowell Brent
Published: February 2019

Mutant endosperm associated with shrunken-2 sweet corn possesses a high osmotic potential that increases the rate of imbibition. Membrane damage associated with the rapid influx of water during imbibition can play a role in the poor emergence and seedling vigor associated with sweet corn germination. Film-coating as a seed treatment has been used to improve germination and vigor in sweet corn. This improvement may be associated with alterations in the kinetics of imbibition. Two seed lots of shrunken-2 sweet corn, low-vigor `Even Sweeter' and high vigor `Sugar Bowl', were treated with a polymer film-coating and evaluated for differences in water uptake. Imbibition curves were established for nontreated and film-coated seeds. Seeds were weighed every hour for 6 hours and showed a significant difference between the two treatments in fresh weight for both cultivars. This pattern continues throughout the imbibition phase of germination and continues into the lag period. Bulk conductivity tests resulted in no significant mean difference between untreated and film treated seeds after 24 hours. Film treatment assumes characteristics of a hydrophilic polymer. Electrolyte leakage is not reduced and imbibition rate increases by 18% for both varieties of film-coated seeds.
Evolution of the Southeast Greenhouse Conference and Trade Show
Authors: Bailey Douglas A.
Published: February 2019

The 8th annual Southeast Greenhouse Conference and Trade Show (SGCTS) will be held in June 2000. This meeting is the result of cooperative efforts among the Alabama Nurserymen's Association, Florida Nurserymen and Growers Association, Georgia Commercial Flower Growers Association, North Carolina Commercial Flower Growers' Association, South Carolina Greenhouse Growers Association, Tennessee Flower Growers Association, Virginia Greenhouse Growers Association; and the Cooperative Extension Services and Land Grant Universities of all seven participating states, including Auburn Univ., Clemson Univ., the Univ. of Florida, the Univ. of Georgia, North Carolina State Univ., Univ. of Tennessee, Virginia Polytechnic Institute and State Univ., and Virginia State Univ. Through pooling of efforts and resources, the SGCTS has become one of the major floriculture educational and trade show events in North America, and it has grown from an initial participation of 347 and a trade show of 89 booths in 1993 to 2407 participants and 398 booths in 1999. The SGCTS serves as an excellent example of cooperative partnering among grower organizations, Cooperative Extension, and faculty at Land Grant Institutions. It eliminates duplication of efforts among individual states, each historically holding their own state meeting. Proceeds from the conference support grower organizations, which in turn support research and educational programs at the cooperating universities. Over $55,000 were disbursed back to the state associations in 1999.
Scarification and Moisture Effects on Triploid Watermelon Seed Germination
Authors: Grange S. , Leskovar D.I. , Pike L. , Cobb G.
Published: February 2019

Triploid watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] consumption is increasing in the United States However, some of the original problems, poor and inconsistent germination, still exist. Seeds of several triploid and diploid watermelon cultivars were subjected to a variety of treatments to improve germination. Control and scarified seeds, by nicking, were incubated at 25 or 30 °C in either 5 or 10 mL H2O or hydrogen peroxide (H2O2). Triploid seed germination was strongly inhibited in all cultivars when seeds were at 10 mL of H2O or H2O2; both nicking and H2O2 increased germination but not equal to rate of the control in 5 mL H2O or H2O2. Germination of diploid cultivars was unaffected by any treatment. Seed morphological measurments indicated that triploid seed has a smaller embryo with a large and highly variable (cv = 105%) air space surrounding the embryonic axis as compared with the diploid seed. These data suggests that triploid watermelon seed germination is not inhibited by the seed coat thickness alone. Seed moisture plays a significant role in germination, emergence, and stand uniformity.
Effects of Nitrogen Application Rate and Supplemental Potassium on Fall Production of Nursery Crops
Authors: Crnko G. Stephen , Bush Edward W. , Owings Allen D.
Published: February 2019

A study was initiated to determine the effects of fall fertilization, specifically N application rate and additions of supplemental K on the production of woody ornamental shrub species. The influence of two slow-release sources of K (4- and 8-month) in the form of K2SO4, three K application rates (0, 1, 2 lb/yd3), and four incorporated application rates of N (0, 1, 2, and 3 lb/yd3) from Osmocote Plus+ 15-9-11 were evaluated on the growth of `Fisher Pink' Indian azalea, glossy abelia, and `Tuscarora' crape myrtle. Growth of `Fisher Pink' azalea, as determined by shoot height and shoot width, increased as N rate increased from 1 to 3 lb/yd3 when compared to the control. The resulting growth index improved at the 2 and 3 lb/yd3 N rate when compared to the 0 and 1 lb/yd3 N rates. Height and width of glossy abelia at the 1 lb N rate with or without supplemental K applications increased when compared to some glossy abelia at the 3 lb N rate (primarily those with supplemental K). Glossy abelia at the 2 lb/yd3 N rate with 2 lb/yd3 N from 4-month 0-0-46 had significantly greater shoot dry weight when compared to the 3 lb/yd3 N rate with 2 lb/yd3 N from 8-month 0-0-46. The 1 to 3 lb/yd3 N application rate had more of a response on growth index, visual quality, and visual color on `Tuscarora' crape myrtle as compared to the 0 lb/yd3 N rate. In this study, the potential influence of supplemental K applications on plant growth was mostly evident for glossy abelia at the 2 lb/yd3 N rate and was not evident on azalea or crape myrtle.
The Effect of Prodiamine on Growth of Containerized Woody Ornamentals
Authors: Bush Edward , Gray Ann L. , Thaxton Virginia , Owings Allen
Published: February 2019

Previous research has shown the effectiveness of prodiamine (FactorÆ)as a preemergent herbicide. The objective of this experiment was to evaluate the efficacy and phytotoxicity of prodiamine applied to several woody ornamental and weed species. Phytotoxicity effects were evaluated on eight ornamental species: azalea (Rhododendron indicum `Mrs. G.G. Gerbing'), dwarf yaupon (Ilex vomitoria `Nana'), dwarf mondograss (Ophiopogon japonicus `Nana'), ixora (Ixora coccinea), lantana (Lantana camara `New Gold'), Southern live oak (Quercus virginiana), weeping fig (Ficus benjamina), and daylily (Hemerocallis fulva). Preemergent herbicide treatments (control-nontreated, 2 lbs aia Factor®, and 4 lbs aia Factor®) were applied to ornamentals twice during the experiment at twelve week intervals. There was a reduction in top dry weight for azalea and dwarf mondograss for both 2 and 4 lbs aia treatments. No significant growth reductions were measured for daylily, dwarf yaupon, ixora, lantana, live oak, and weeping fig. The efficacy experiment consisted of four weed species: barnyardgrass (Echinochloa crusgali), crabgrass (Digitaria sanguinalis), coffeeweed (Sesbania exaltata), and pigweed (Amaranthus retroflexus) and five preemergence herbicide treatments (control-nontreated, control-Rout® at 100 lbs/A, Factor® 1 lb aia, Factor® 2 lbs aia, and a tank mixture of Factor® 1 lb aia plus Gallery® 1 lb aia) applied to bark-filled containers. Twenty-five weed seeds of each species were broadcast over each container following herbicide applications. The high rate of Factor®, Rout®, and the combination of Factor®+Gallery® significantly reduced weed dry weight compared to the control. All preemergence herbicides significantly reduced weed counts and height in a similar manner.
Growth and Performance of Some Woody Plants Grown under Salinity Stress
Authors: Al-Badawy Ahmed A. , El-Amry M. I. , Salem M. A.
Published: February 2019

Six woody plant species, (Atriplex lentiformis, Acacia ampliceps, Conocarpus erectus, Conocarpus erectus var. sericeus, Laguncularia racemosa, and Thespesia populnea) different in age, were grown in the field and irrigated with saline water (25 ppt). The physiological performance of these species was measured. Some macro- and micro-elements, carbohydrates, protein, proline, and photosynthetic pigments were estimated in the plants. The obtained results indicated in most cases, that age of plants has no effect on nutrients, protein, or carbohydrate concentrations. For each plant species, there were some differences in the chemical composition of the leaves and stems. No significant differences were detected in Mg and Mn concentrations in leaves and stems of all studied species. Photosynthetic pigments and proline concentrations were different depending on the plant species and age. The air and leaf temperature differentials, leaf conductance, and transpiration rate were also discussed. The overall growth and physiological performance of these plants was good.
`Green Pixie': A Green Cotyledon, Cream-type Southernpea
Authors: Fery R.L.
Published: February 2019

The U. S. Department of Agriculture released the small-seeded, cream-type southernpea cultivar Green Pixie on 4 Mar. 1999. The new cultivar is homozygous for the gc gene conditioning the green cotyledon trait. `Green Pixie' seeds can be harvested at the dry stage of maturity without loss of their fresh green color. `Green Pixie' originated as a bulk of an F9 (`White Acre' × `Bettergreen') population grown in 1994. `Green Pixie' has a high, bushy plant habit similar to `White Acre'. It produces dry pods at Charleston, S.C., in ≈76 days, 5 days later that `Bettergreen' and 5 days earlier than `White Acre'. The rhomboid-kidney shape of fresh `Green Pixie' seeds is quite similar to the shape of fresh `White Acre' seeds, but very different from the ovate to reniform shape of fresh `Bettergreen' seeds. `Green Pixie' seeds are quite similar in size to `White Acre' seeds, but much smaller than `Bettergreen' seeds (weight per 100 dry seeds: `Green Pixie', 8.0 g; `White Acre', 7.9 g; and `Bettergreen', 10.2 g). The results of replicated field trials indicate that the yield potential of `Green Pixie' is equal to that of `Bettergreen' and `White Acre'. `Green Pixie' is the first cream-type, green-cotyledon cultivar to be developed that yields seeds that are similar in size and shape to `White Acre' seeds. It is recommended for trial as a replacement for `White Acre' when grown to produce raw product for a frozen pack.
Nitrogen Rate Response on `Cape Fear' Southern Highbush Blueberry
Authors: Carter Manjula , Clark John R. , Phillips Mike
Published: February 2019

The southern highbush blueberry is a hybrid of Vaccinium corymbosum L. and one or more southern-adapted Vaccinium species. The southern highbush is advantageous to blueberry growers in the South since its fruit ripen 1 to 4 weeks in advance of traditional rabbiteye (V. ashei Reade) cultivars. Only limited research has been done on cultural aspects of southern highbush production. The objective of this study was to determine the optimum nitrogen rate for the southern highbush blueberry. A planting of pine straw-mulched `Cape Fear' blueberry was established in 1994 at the Southwest Research and Extension Center, Hope, Ark. Nitrogen rate treatments (0, 67, 134, 202, 269 kg·ha-1 N) were applied annually over a 3-year period (1997-99) with urea as the N source. Soil samples were taken prior to N fertilization to determine if N applied the previous year influenced current soil analysis values. Foliar elemental composition, fruit yield and individual berry weight were also determined for each treatment. Soil analysis indicated that the carryover effect of N applications from previous years was minimal. However, a possible decline in soil pH, Ca, and Mg over time at the higher N rates indicated that these variables should be closely monitored. No consistent relationship was evident between N application rate and soil nitrate. Nitrogen application rate did not have any consistent impact on yield, berry weight or foliar elemental composition. However, based on foliar N, the data indicate that N rates of 67-134 kg·ha-1 N are adequate for southern highbush in mulched culture.
Water Use by Drip-irrigated Watermelons on Plastic Mulch
Authors: Bender David A. , Roberts Roland E. , Dainello Frank J.
Published: February 2019

Watermelon is grown under a range of moisture regimes from rainfed to heavily irrigated, but water requirement patterns are not well documented. Drip irrigation and plastic mulch provide the opportunity to control water applications to optimize yield and quality. Water applied through subsurface drip irrigation was measured in two watermelon trials in 1998 (25 seeded and 20 seedless cultivars) and 1999 (26 seeded and 14 seedless cultivars) at Lubbock, Texas. Melons were transplanted in plastic-covered raised beds 13.6 m long spaced 2 m apart. Irrigation was applied when morning soil moisture tension measured by tensiometers exceeded 20 kPa. Watermelon yields ranged from 50 to 100 t·ha-1 with excellent quality. Weekly water use averaged 14 mm during the first 3 weeks of establishment then increased to 28 mm during the next 3 weeks as plants were running and blooming. During the 5-week fruit-enlargement period, water uptake averaged 57 mm, then decreased as full fruit size was attained. Similar uptake patterns in both years suggest that meaningful crop coefficients for scheduling watermelon irrigation could be based on phenological growth stages.
Determination of Optimal Storage Temperature to Maintain Viable Pawpaw [Asimina triloba (L.) Dunal] Seed
Authors: Pomper Kirk W. , Jones Snake C. , Barnes LaTeasa
Published: February 2019

Pawpaw is a native American tree fruit that has great potential as a new commercial crop. The USDA National Clonal Germplasm Repository for Asimina sp. is located at Kentucky State Univ. (KSU); therefore, germplasm collection and storage are important components of the research program. Recalcitrant seeds do not tolerate desiccation, have a relatively short period of viability, and tend not to tolerate subfreezing temperatures. Since pawpaw seed shows a moderate level of recalcitrance, the objectives of this experiment were to determine which storage temperatures (20, 5, -15, and -70 °C for 8.5 weeks) would maintain viable seed, and whether prior seed stratification (5 °C for 17.5 weeks) would influence survival at the various storage temperatures. Seeds were placed in ziplock bags in moist peat moss and subjected to the range of storage temperatures either before or after stratification. After storage and stratification treatments, seed germination rate was examined for 10 weeks at 25 °C on moist filter paper in petri dishes. Both stratification and storage temperature significantly affected seed germination rate. Seeds did not germinate after storage at subfreezing temperatures, regardless of stratification treatment. The best germination rate, ≈70%, was obtained with stratification followed by storage at 20 °C. However, for long-term storage of viable nongerminating pawpaw seed, stratification followed by storage at 5 °C would be most appropriate. Subfreezing storage temperatures were found to be lethal to pawpaw seeds.
Bed and Row Configuration Studies
Authors: Parish Richard L. , Bracy Regina P.
Published: February 2019

Two studies were conducted on bed and row configurations. The first compared erosion effects on stand count with single and double drill plantings; the second evaluated bed heights. Vegetables are usually planted on raised beds in the Deep South. Both single and double drills per bed are common. The double drills offer higher yields in some cases, but may be difficult to maintain because of erosion on the bed sides after heavy rainfall. A series of plantings of cabbage (Brassica oleracea L. Capitata group) and broccoli (Brassica oleracea L. Italica group) was made over a period of nearly a year to compare stands from single and double drills. Heavy rainfall did not occur after any of the 18 plantings, so bed erosion did not occur. Differences in percent stand were few, although in a few cases the double drill planting resulted in higher stands. A field study was conducted to determine the optimum bed height for leafy greens crops grown on shaped beds. Bed heights of 5, 10, 15, and 20 cm (2, 4, 6, and 8 in) were evaluated with crops of mustard [Brassica juncea (L.) Czerniak.] and turnip (Brassica rapa L. Rapifera group) during three crop seasons. Few significant differences in stand count, yield, or product quality resulted from the different bed heights. A trend toward lower yields, quality, and reduced efficacy of precision cultivation was noted with the 5-cm (2-in) bed height.
Trifluralin Rate Affects Cabbage Stands
Authors: Bracy R.P. , Parish R.L. , McCoy J.E.
Published: February 2019

Difficulty in obtaining and maintaining an adequate plant stand in directly seeded cabbage led to the investigation of possible causes of plant loss. A series of experiments was conducted evaluating the effect of six rates (0, 0.28, 0.41, 0.56, 0.84, 1.12 kg·ha–1 a.i.) of trifluralin on cabbage stand. The treated area was irrigated immediately after planting; one-half of the area received overhead irrigation and the other half received furrow irrigation. Activated charcoal as a slurry was sprayed at the rate of 336 kg·ha–1 directly into the seed furrow on half the plots receiving the higher trifluralin rates. Plots treated with trifluralin at rates of 0.56, 0.84, and 1.12 kg·ha–1 had lower plant populations if activated charcoal was not applied. Grass, broadleaf, and sedge weed control was as effective with 0.28 and 0.41 kg·ha–1 of trifluralin as it was at the higher rates of 0.56, 0.84, and 1.12 kg·ha–1. Plant population was not affected as much by trifluralin rates when furrow irrigation was used as compared with overhead irrigation. Producers should be careful not to exceed 0.41 kg·ha–1 of trifluralin on cabbage directly seeded into light-textured soils, because reduced stands can be expected.
Phytotoxicity of Potential Postemergence Herbicides for Jalapeno Peppers
Authors: Bender David A. , Keeling J. Wayne , Roberts Roland E.
Published: February 2019

Large weeds, particularly amaranths, are a serious impediment to mechanical harvesting of jalapeno peppers. Several herbicides were applied in 1998 and 1999 postemergence topical (PT) to commercial fields when peppers had four to six leaves, or postdirected (PD) with a shielded sprayer ≈1 month later, and evaluated for crop injury, weed control, and effects on yield. Treatments were applied to four-row plots 9 m long with a CO2 backpack sprayer. PT treatments included pyrithiobac sodium at 0.036, 0.053, or 0.071 kg·ha–1 a.i. with nonionic surfactant or crop oil concentrate, metolachlor at 1.68 kg·ha–1 a.i., and oxyfluorfen at 0.14 or 0.28 kg·ha–1 a.i.. PD treatments consisted of the same rates of pyrithiobac sodium with nonionic surfactant only, and the same rates of oxyfluorfen. Pyrithiobac sodium PT caused significant chlorosis (reduction in SPAD chlorophyll) in new foliage and reduction in plant height after 1 week, but plants recovered with no effect on final plant height, chlorophyll, or yield. No significant difference was observed between the two adjuvants. Metolachlor had no measurable effect on pepper growth or yield. Oxyfluorfen PT killed young apical tissue and caused chlorosis of immature leaves. Plants recovered, but plant height was reduced by 14% to 28% and yield by 11% to 43%. PD treatments had no effect on pepper growth or yield. All herbicides provided adequate weed control under light pressure. Pyrithiobac sodium appears to have potential as a postemergence herbicide for control of amaranth in jalapeno peppers.
The Kentucky Tomato, Part II
Authors: Rowell Brent , Jones Terry , Snyder J.C.
Published: February 2019

We conducted trials of vine-ripened, staked tomato cultivars in 1998 and 1999 to identify a variety suitable for marketing as a premium “Kentucky Tomato.” Essential qualities of our ideal Kentucky tomato were determined in conversations with marketing specialists at the Kentucky Dept. of Agriculture and merchandising managers from the state's largest supermarket chain. A carefully selected group of 14 varieties (including 10 from the 1998 trial) was evaluated at two locations for yields, returns per acre, appearance, and quality in 1999. New varieties were compared with commercial standards `Mountain Spring' and `Mountain Fresh'. Yields of different sizes and grades of marketable fruit were multiplied by appropriate market prices for a given harvest date and summarized in a single “income per acre” variable for each variety. Although many varieties were in the highest 1999 income group (`Fabulous', `Mountain Spring', `Emperador', `Florida 47', `Sunleaper', `Floralina', `Mountain Fresh', `SunGem', NC 98274, `Enterprise'), not all were acceptable in terms of fruit quality and firmness. `Fabulous' and `Emperador' had higher percentages of fruits with radial cracks at one location in 1999 than in 1998. Consumer taste tests were conducted in 1998 and `Mountain Fresh' and `Floralina' were considered the best tasting among the six varieties tested. `Sunleaper', `Floralina', `SunGem', NC 98274, and `Fabulous' (for local markets) together with `Mountain Fresh' were considered prime `Kentucky Tomato' candidates and were recommended for further testing in farmers' fields in 2000.