bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of DNA Markers to the Identification of Horticultural Plants
Authors: Zhang Donglin , Dirr Michael A. , Price Robert A.
Published: February 2019

The correct identification of horticultural taxa becomes more and more important for intellectual property protection and economic reasons. Traditionally, morphological characteristics have been used to differentiate among the horticultural taxa. However, the morphological characteristics may vary with plant age, cultural conditions, and climate. Modern technologies, such as DNA markers, are now employed in the identification of horticultural taxa. Currently, technologies of DNA sequencing (gene sequences) and DNA fingerprinting (RAPD, RFLP, SSR, and AFLP) are available for distinguishing among horticultural taxa. The literature and our personal experience indicate that the application of each technique depends on the taxon and ultimate goal for the research. DNA sequencing of a variety of nuclear or chloroplast encoded genes or intergenic spacers (rbcL, ndhF, matK, ITS) can be applied to distinguish different species. All DNA fingerprinting technologies can be used to classify infraspecies taxa. AFLP (the most modern technique) is the better and more-reliable to identify taxa subordinate to the species, while RAPDs can be employed in clonal or individual identification. Techniques of RFLP and SSR lie between AFLP and RAPD in their effectiveness to delineate taxa. Mechanics, laboratory procedures, and inherent difficulties of each technique will be briefly discussed. Application of the above technologies to the classification of Cephalo taxus will be discussed in concert with the morphological and horticultural characteristics. Future classification and identification of horticultural taxa should combine DNA technology and standard morphological markers.
Alterations in Gene Expression during Exposure of Bermudagrass to Low, Non-lethal Temperatures
Authors: Wells John , Baird Wm. V.
Published: February 2019

Temperature is a limiting factor for plant growth. Warm-season turfgrasses can experience winter-kill when grown in the “transition zone.” On the other hand, when properly cold-acclimated, these same plants can withstand otherwise lethal temperatures. As part of our investigations into the biochemistry and molecular biology of cold acclimation in bermudagrass, total RNA from crowns (rhizome buds) isolated at different timepoints before and after chilling temperature exposure, was isolated by salt-buffer/phenol extraction, followed by LiCl precipitation and DNAse treatment. Differential display reverse transcriptase polymerase chain reaction (DD-RT-PCR) was performed using specific-(dT11NN) or variable-(dT12VN) anchor primers (where V = dA, dG and dC and N = dA, dG, dC or dT) for first strand cDNA synthesis by RT. The ss-cDNAs were converted to double stranded molecules and PCR amplified using a randomly chosen 10-mer primer paired with the same anchor primer used for cDNA synthesis. The dCTP32 labeled cDNAs were fractionated on non-denaturing polyacrylamide gels. Individual bands exhibiting differential expression between treated and nontreated samples were identified for reamplification, cloning, sequencing and further characterization of the differential nature of their expression by reverse northern hybridization and RT-PCR. Only those excised bands able to be reamplified using the anchor:10-mer pair were selected for cloning. To date, 90 variable-anchor:10-mer or specific-anchor:10-mer pairs have been screened. Of these, ≈27 have exhibited possible differential expression with one or more bands. Nucleotide (and deduced amino acid) sequence information was used to search on-line databases for similarity/homology with previously reported gene or protein sequences.
Agrobacterium-mediated Transformation of Three Elite Hybrid Aspens
Authors: Bosela M.J. , Schnurr J.P. , Cheng Z.-M. , Sargent W.A.
Published: February 2019

Three elite hybrid aspen, Populus grandidentata × P. canescens, P. tremuloides × P. tremula, and P. tremuloides × P. davidiana, have been transformed with Agrobacterium tumefaciens strains LBA4404 and EHA105 carrying kanamycin resistance and GUS genes. The leaves of micropropagated shoots were co-cultivated with Agrobacterium for 65 to 72 hr and then transferred to callus-induction medium with 80–120 mg/L kanamycin in the dark. After 2 weeks, the leaves were transferred to shoot-induction medium under 18-hr photoperiod. Regenerated shoots were verified for transformation by histochemical staining and PCR. Transformed shoots rooted and were transplanted to soil. The three hybrid clones differed widely in their medium requirements for regeneration and in their competence for transformation. The leaves of P. grandidentata × P. canescens callused vigorously on a wide variety of media. In a typical transformation experiment, 30% to 60% of infected leaves produced putatively transformed calli (up to 10 calli per leaf). The origin of these calli and the frequency of shoot formation depended on the Agrobacterium strains. The calli from EHA105-infected leaves produced shoots within six weeks of co-cultivation and at high frequencies (70% to 90%). However, the calli from LBA4404-infected leaves produced shoots more slowly and at much lower frequencies (5% to 10%). Delaying selection for 2 weeks was found to lower the transformation frequency. Putatively transformed calli were obtained from P. tremuloides × P. tremula, and P. tremuloides × P. davidiana hybrids at frequencies of only 2% to 3%. The calli regenerated from P. tremuloides × P. davidiana leaves were very small, but they continued to grow upon being transferred to shoot-induction media and have started to produce shoots. The calli from leaves of P. tremuloides × P. tremula were much larger and they produced shoots more quickly. This transformation protocol is currently being used to introduce rooting genes into these hybrids to improve their rooting from hardwood cuttings.
Scald-related Volatiles in the Epicuticular Wax of Apple Fruit
Authors: Wee S. , Beaudry R.M.
Published: February 2019

Volatile compounds produced by apple (Malus domestica Borkh) fruit partition into the cuticle and epicuticular waxes and may play an important role in superficial apple scald. Of these volatiles, α-farnesene, conjugated trienes, hydroperoxides, and 6-methyl-5-hepten-2-one have been identified as playing a crucial role in scald production. Volatiles from the epicuticular wax of four different apple cultivars have been analyzed by gas chromatography/mass spectroscopy. A correlation was found between scald incidence and 6-methyl-5-hepten-2-one content and the 6-methyl-5-hepten-2-one:α-farnesene ratio. α-Farnesene is the most-abundant volatile at the beginning of storage, whereas 6-methyl-5-hepten-2-one is present in minute quantities. These two volatile compounds appear to have an inverse relationship with respect to one another since the levels of 6-methyl-5-hepten-2-one increased and α-farnesene decreased prior to the onset of apple scald. This changing ratio may have been due to an autoxidative process resulting in the breakdown of α-farnesene to 6-methyl-5-hepten-2-one. Analysis of the volatiles emanating from the apple wax revealed a number of compounds associated with aroma that also partition readily into the fruit surface.
Duration and Persistence of Heat Shock Induction of Chilling Tolerance in Cucumber Seedling Roots
Authors: Zhang Hua , Jennings Paul H.
Published: February 2019

The effects of heat shock duration and persistence on the induction of chilling tolerance in cucumber roots were studied using total root growth, electrolyte leakage, and membrane peroxidation as injury indices after chilling. Heat shock reduced the chilling induced electrolyte leakage, decreased membrane peroxidation as measured by MDA content, and resulted in a greater total root growth after chilling compared to the control. Heat shocks at 40°C, applied to 36 hr germinated seedlings for time periods from 1 to 15 hr, all resulted in an increase in chilling tolerance in a time-dependent manner. The heat shock induction of chilling tolerance is most effective when heat shock was imposed immediately before chilling, but the effect is persistent even 32 hr after heat shock when seedlings are held at 25°C before chilling. The possible mechanism of heat shock effect and its persistence will be discussed in relation to heat shock proteins and antioxidant enzyme systems.
The Influence of Organic Fertilization and Different Plant Densities on Physiological Traits and Production of Nopal (Opuntia spp.) under Plastic Tunnels
Authors: Murillo-Amador B. , Troyo-Dieguez E. , orrego-Escalante F.
Published: February 2019

The response of physiological traits of four genotypes of Opuntia spp (AN-V1, AN-V3, AN-V5, and AN-TV6) to organic fertilization with two levels of thickness and different plant densities (10, 20, 30, 40, and 50 plants/m2) under plastic tunnels were studied in the Universidad Autnoma Agraria “Antonio Narro” in 1995 and analyzed at CIBNOR, La Paz, Mexico. The main goal of this work was to screen Opuntia genotypes for yield and photosynthetical efficiency. The experiment was established as a randomized blocks design with three replicates. Response variables were dry weight (DW), crop growth ratio (CGR), rate of crop growth (RCG), relative growth rate (RGR), leaf area index (LAI), and net assimilation rate. The annual average temperature in the study site was 19.8°C. Hottest months were July and August, with temperature values as high as 39°C. The lowest temperatures were recorded in December and January, with temperatures as low as –13°C. Annual rainfall was 365 mm. Soils in the study region show a generalized low fertility. According to our results, genotype AN-V1 showed the best photosynthetical features with 30 plants/m2; genotype AN-TV6 showed no differences for 40 and 50 plants/m2. The highest values for CGR and RCG were observed under the highest level of organic fertilization (16-cm thickness). Genotypes AN-V3 and AN-V5 evidenced the highest RCG. Other results suggest that AN-V3 and AN-V5 showed the highest value for LAI, for a density 50 plants/m2, and genotypes AN-V1 and AN-V3, with a density 40 plants/m2, had the highest RGR. The studied Opuntia genotypes appeared to be promising crops for marginal semiarid regions.
Integration of Cover Crops and Strip-tillage Systems for Vegetable Production
Authors: Luna John , Staben Mary , O'Brien Tim
Published: February 2019

Five on-farm trials were conducted in the Willamette Valley of western Oregon in 1996 to evaluate the potential for integrating winter-annual cover crops and rotary strip-tillage in vegetable productions systems. Two kinds of rotary strip tillers were used to till strips into killed winter cover crops or wheat stubble. Strip-tillage systems were compared to the “standard tillage” practices of the participating growers. In two sweet corn trials, yield of sweet corn was reduced ≈1 MT/ha in the strip-tillage treatments, compared to the standard tillage practices used by the growers. In these trials, the number of tillage operations was reduced by four to five passes with the strip-tillage system. In two other sweet corn trials, corn yield was reduced by ≈4.5 to 5.6 MT/ha in the strip-till treatments compared to the standard tillage treatments. In a transplanted broccoli trial, the strip-tillage and standard tillage treatments produced comparable yields. Possible factors reducing crop yield in the strip till systems include reduced soil temperature at planting and during early growth, soil moisture depletion in the undisturbed cover crop areas, soil compaction, nitrogen immobilization by the cover crop, weed competition, and possible glyphosate/microbiological interactions. Although an economic analysis of this project has not yet been completed, a rough estimate of tillage costs at $25/40 per pass per ha suggests that, in the field with only a 1 MT/ha yield reduction, the reduction in tillage costs would offset the yield reduction in corn (valued at about $88/MT). If yield reducing factors can be understood and a predictable, manageable system of strip-till vegetable production developed, there is a potential to dramatically reduce tillage costs and enhance soil quality through conservation of soil organic matter and biological diversity.
Finite Dose Diffusion of Urea through Isolated Citrus Leaf Cuticles
Authors: Bondada Bhaskar , Petracek Peter D. , Syvertsen Jim
Published: February 2019

Recent interest in reducing nitrate levels in ground water has stimulated the re-examination of foliar application of urea on citrus trees. Because the cuticle is the primary barrier to foliar uptake, we examined the diffusion of 14C-urea through isolated citrus leaf cuticles. Cuticles were enzymatically isolated from leaves of the four youngest nodes (1 month to 1 year old) of pesticide-free grapefruit trees. The diffusion system consisted of a cuticle mounted on a receiver cell containing stirred buffer solution. Urea (1 μL) was pipetted onto the cuticular surface, and buffer solution was sampled periodically through the side portal of the receiver cell. The time course of urea diffusion was characterized by lag (time to initial penetration), quasi-linear (maximum penetration rate), and plateau (total penetration) phases. Apparent drying time was less than 30 min. Average lag time was about 10 min. The maximum penetration rate occurred about 40 min after droplet application and was about 2% of the amount applied per hour. Rewetting stimulated further penetration. The total penetration averaged about 35% and tended to decrease with leaf age. Dewaxing the second node cuticles by solvent extraction significantly increased maximum penetration rates (30% of the amount applied per hour) and total penetration (64%).
Seasonal Fluctuation of Promoters and Inhibitors of Adventitious Root Formation in `Nabali' Olive Shoots
Authors: Qrunfleh Mostafa M. , Amr Khalid A.
Published: February 2019

Four fractions from known dry weights from buds or leaves of `Nabali' olive shoots—nonacidic ethylacetate (F 1), acidic ether (F 2) and acidic-n-butanol (F 3) were obtained for several sampling dates. A fourth fraction (F 4) from F 1, F 2, and F 3 was established. The four crude fractions were bioassayed for adventitious root formation using mung bean cuttings. In another extraction, fractionation by paper chromatography was performed to identify promoters and inhibitors using the Rf values and mung bean bioassay. The results indicated absence of rooting inhibitors in buds and leaves of `Nabali' olive in mung bean bioassay in all four crude extracts and their fractions located at the various Rf values. However, rooting promoters from buds and leaves were detected by mung bean bioassay in all crude extracts. F 1 contained rooting promoters located at Rf 0.5 and 0.6 throughout the period from 20 Nov. to 2 Apr.; these promoters were found to be highest in buds sampled 23 Feb. and in leaves sampled 4 Dec. and 4 Feb. F 2 from buds and leaves showed neither promoting nor inhibitory activities. F 3 (from leaves or buds) contained promoters of rooting located at Rfs from -.4–0.7 throughout the sampling periods. However, F 3 from buds on 9 Dec., 23 Feb., and 2 Apr.; and from leaves on 4 Feb. gave significantly highest root-promoting activity. F 4 from buds and leaves showed root-promoting effects from November to April. The promoting effect of F 4 was greatest in buds and leaves sampled 9 Dec. and 4 Feb., respectively.
Pot-in-pot Production and Cyclic Irrigation Influences Growth and Evapotranspiration of `Okame' Cherry
Authors: Ruter John M.
Published: February 2019

A study was conducted with Prunus × incamp `Okame' to evaluate the effects of a pot-in-pot production system compared to a conventional above-ground system and cyclic irrigation on plant growth and water loss. Plants were grown in #7 (26-L) containers with a 8:1 pinebark:sand (v/v) substrate. Cyclic irrigation provided the same total volume of water, but was applied one, three, or four times per day. Final plant height and stem diameter, shoot and root dry weight, total biomass, and root:shoot ratio were all increased for plants grown pot-in-pot compared to above-ground. Multiple irrigation cycles increased stem diameter, shoot dry weight, and total biomass, compared to a single irrigation application. Multiple irrigation cycles decreased the root:shoot ratio. Evapotranspiration was influenced by production system, irrigation, and date. Amount of water lost as leachate was influenced by irrigation and date. Cyclic irrigation resulted in a two-fold decrease in leachate volume. Soluble salts and nitrate-nitrogen in the leachate were influenced by an interaction between production system, irrigation, and date.
Growth After Mechanical Root Pruning of Herbaceous Perennials under Increasing Levels of Water Stress
Authors: Dunn Scott W. , Klett James E.
Published: February 2019

Perennials grown in 5.7-cm containers received two root treatments (mechanical root-pruned and non-pruned) prior to field planting. During the 1996 season, the two root treatments and five irrigation treatments, (0%, 25%, 50%, 75%, 100%) ET0 (reference crop evapotranspiration), were tested on Delosperma cooperii, Delosperma nubigenum, Polygonum affine, and Veronica liwanensis and evaluated on the basis of plant growth and visual ratings. No significant change in height occurred in any species for both root or irrigation treatments. No significant change in width or density occurred in D. cooperii, from root treatment; however irrigation treatments below 50% resulted in a significant decrease in width. Significant deceases in width also occurred in all species from irrigation treatments. Mechanically root-pruned plants resulted in a significant decrease in density of D. nubigenum, P. affine, and V. liwanensis and a decrease in width in P. affine.
Influence of Stratification, Temperature, and Light on Seed Germination of Selected Provenances of Atlantic White Cedar
Authors: Jull Laura G. , Blazich Frank A.
Published: February 2019

Cones of six provenances (Escambia Co., Ala., Santa Rosa Co., Fla., Wayne Co., N.C., Burlington Co., N.J., New London Co., Conn., and Barnstable Co., Mass.) of Atlantic white cedar [Chamaecyparis thyoides (L.) B. S. P.], were collected Fall 1994 (Alabama, North Carolina, New Jersey, and Connecticut), Winter 1995 (Massachusetts), or Fall 1995 (Florida). Cones were dried for 2 months, followed by seed extraction and storage at 4°C. Seeds were then graded and stratified (moist-prechilled) for 0, 30, 60, or 90 days. Following stratification, seeds were placed at 25°C or an 8/16-hr thermoperiod of 30°/20°C with daily photoperiods of 0, 1, or 24 hr. Germination was recorded every 3 days for 30 days. Temperature, stratification, and light had significant effects on germination. However, responses to these factors varied according to provenance. Averaged over all treatments, the Alabama provenance exhibited the greatest germination (61%), followed by the Florida provenance (45%), with the remaining provenances ranging from 20% to 38%. However, there were specific treatments for each provenance that resulted in germination > 50%. The three southern provenances (Alabama, Florida, and North Carolina) required 30 days of stratification for maximum germination. They did not exhibit an obligate light requirement, but photoperiods ≥ 1 hr increased germination greatly over seeds in darkness. In contrast, the northern provenances (New Jersey, Connecticut, and Massachusetts) had an obligate light requirement. These provenances only required 30 days stratification with continuous light for maximum germination. When subjected to a 1-hr photoperiod, seeds from the northern provenances required longer durations of stratification for maximum germination. Regardless of the length of stratification, the New Jersey provenance required a 24-hr photoperiod to maximize germination. When averaged over all treatments, total germination for each provenance was greater at 30°/20°C than 25°C (43% vs. 31%).
Developmental and Environmental Control of Dry Matter Partitioning in Peach
Authors: DeJong T.M.
Published: February 2019

For the last several years, research in my laboratory has been focused on studying the developmental and environmental control of dry matter partitioning in peach trees based on the concept that plants grow as collections of semi-autonomous, but interacting, organs. This concept assumes that plant genotype, triggered by developmental and environmental signals, determines current organ specific growth potentials and that environmental conditions dictate conditional growth capacity and respiration (both growth and maintenance) requirements of each organ at any specific time. Dry matter partitioning at any given time is then determined by the availability of resources to be partitioned, the conditional growth capacity and maintenance requirements of each organ, and the relative ability of each organ to compete for the resources. In this presentation, I will demonstrate how developmental patterns of various organs influence dry-matter partitioning within the tree over time, how organ number can influence the amount of dry-matter partitioned collectively to an organ type, and propose an hypothesis for how environmental conditions may influence partitioning on a diurnal basis.
Photoassimilate Production and Distribution in Stone Fruit
Authors: Flore J.A. , Layne Desmond
Published: February 2019

Resource partitioning between individual sink organs is dependent upon the supply of carbon from current photosynthesis and reserves, the relative ability of the translocation system to deliver resources to the sinks, and the strength or competitive ability of the sinks. To comprehend photoassimilate distribution in Prunus, one must have a general understanding of habitat, growth patterns, and changes in sink demand over the life cycle and seasonal development of the plant. In this review, we describe assimilation rates for the major Prunus species and general dry matter allocation patterns, with emphasis on environmental and biological factors that effect photosynthesis, partitioning, and control. The following factors will be covered: annual growth, changes with tree age, environmental and biological factors that effect photosynthesis, genetic factors, water, light, fruiting, and pruning.
Regulation of Mannitol Dehydrogenase: Relationship to Plant Growth and Stress Tolerance
Authors: Pharr D.M. , Prata R.T.N. , Jennings J.B. , Williamson J.D. , Zamski E. , Tamamoto Y. , Conkling M.A.
Published: February 2019

Increasing salinity of agricultural soils may ultimately limit the sustainability of food production in some areas of the world. Work from our laboratory and the labs of others demonstrates that mannitol, a six-carbon sugar alcohol, is important as a stress-related metabolite in some plants. Mannitol helps plants resist the damaging effects of stressful growth environments, such as drought, high soil salinity, and perhaps attack by microorganisms that cause plant diseases. In the long run, we hope to genetically engineer plants to produce and use mannitol for increased productivity and tolerance to environmental stresses. Basic information about how plants regulate those genes important to mannitol metabolism is of critical importance to this long-term goal. Our laboratory discovered an enzyme, mannitol dehydrogenase, that is the first critical biochemical step in mannitol use in vascular plants. Later, we cloned the gene for this enzyme. We discovered that hexose sugars “turn off” the expression of this gene. So, as long as adequate sugars are available for energy, maintenance, and growth, the production of the mannitolusing enzyme is repressed. After the sugars are gone, mannitol dehydrogenase is produced very rapidly, and this allows mannitol to be used metabolically. This type of gene regulation is ideally designed to help plants cells conserve mannitol as long as possible, which in turn allows the cells to retain stress tolerance as long as possible.
Controlling Floral Initiation and Vegetative Growth of Apple with Prohexadione Calcium (BAS-125W), an Experimental GA-biosynthesis Inhibitor
Authors: Owens Christopher L. , Stover Eddie W.
Published: February 2019

Early fruit production and control of tree size are important factors in the economic viability of high-density apple orchards. A horticultural tool permitting growers to induce terminal budset should provide greater control over the balance between vegetative growth and reproduction, increasing orchard production and profitability. With this goal, the experimental GA-biosynthesis inhibitor, BAS-125W, is being evaluated for effects on enhancing floral initiation and controlling tree size in young orchards. In nursery stock, the effect of inducing earlier terminal budset is also being studied for influence on storage carbohydrates and performance after planting. Studies in 1996 showed that 250 ppm BAS-125W induced terminal bud set on actively growing second-leaf `Macoun', `Delicious', and `Fuji' trees. Seven application dates from 17 June to 9 Sept. were compared to determine how time of treatment would effect degree and distribution of flowering the following year. Terminal budset typically occurred 2 weeks after application, with shoot growth resuming in 4 to 5 weeks. At two dates, treatment of growing tips only was compared with entire tree application to distinguish the direct effect of GA-inhibition on floral initiation from the effect of redistributing photosynthate. Treatment from 17 June to 29 July significantly reduced total annual shoot growth compared to the untreated controls, while later treatments had no significant effect on shoot length. Treatments of nursery stock with BAS-125W on 1 Sept. accelerated terminal bud set by at least 7 days compared to untreated controls of both `Fuji' and `Golden Delicious'. Effects of treatments on flowering and tree growth in 1997 will be discussed.
Mode of Action, Metabolism, and Uptake of BAS-125W, Prohexadione Calcium
Authors: Evans J.R. , Ishida C.A. , Regusci C.L. , Evans R.R. , Rademacher W.
Published: February 2019

Prohexadione calcium, or BAS-125W, is a plant growth regulator being developed for registration in the United States by the BASF Corporation and Kumiai Chemical Industry Co. Ltd. Prohexadione calcium inhibits the biosynthesis of gibberellin by blocking dioxygenases, which require 2-oxogluterate as a co-substrate. The result is a decrease in cell elongation and reduced vegetative growth. Gibberellin levels are reduced in the plant for 3 to 4 weeks following application of this growth regulator. Prohexadione calcium does not persist in the plant or directly effect vegetative growth the following season. Prohexadione calcium is absorbed by the plant foliage and uptake is generally complete within 8 hr following application. Results indicate that translocation within the plant is predominantly by acropetal movement, while basipetal movement is limited. Preliminary research has shown prohexadione calcium to have a short half-life in the environment; to have no negative effects on non-target organisms; and to offer little risk to users or consumers. Rates of 125 ppm a.i. to 250 ppm a.i. have typically provided effective vegetative control of vigorous apple trees. Generally, as the vegetative vigor of a tree increases; the rate of prohexadione calcium needed for effective vegetative control has to be raised. Vegetative vigor is influence by numerous factors including: fruit load, location, variety, rootstock, age, pruning, and training system. Earlier applications at 2 to 5 inches of new shoot growth have provided more-effective control of vegetative growth than later applications. Due to its short-term effect and lack of persistence, prohexadione calcium can be a flexible tool in developing user specific growth management strategies.
Performance of Cornus florida L. Selections in the Southeast
Authors: Hardin R.B. , Eakes D J. , Gilliam C.H. , Keever G.J.
Published: February 2019

In a full-sun Auburn, Ala., field study, 23 cultivars and 1 forma of Cornus florida L. were evaluated for growth from 1994 to 1996 and bract characteristics in Spring 1996. The selections were divided into three groups for analyses: 1) white bracted with green foliage, 2) red or pink bracted with green foliage, and 3) variegated foliage. Among the white bracted cultivars with green foliage, `Weaver' and `Welch Bay Beauty' had the greatest height and stem diameter increases, `Autumn Gold' the least. `Cloud 9' had the largest bract size. `Welch's Junior Miss' had the greatest height increase, while `Stokes' Pink' had the greatest stem diameter increase for the red or pink bracted cultivars with green foliage, and f. rubra the least. `Red Beauty' had the largest bract size. There were no differences among the variegated cultivars in height increase or bract size; however, `First Lady' had the greatest stem diameter increase.
Pizza Farm Presents Agriculture to Youth
Authors: Cushman Kent , Sloan Crofton
Published: February 2019

A circular garden, divided into eight sections or “slices,” was established for the purpose of demonstrating agriculture to youth. Each section of the garden represents a form of agriculture associated with the consumption of pizza. Soybeans were planted to represent oil, wheat to represent flour, vegetables to represent tomato sauce and vegetable toppings, herbs to represent spices, and pine trees to represent paper and cardboard products. A dairy cow, beef cow, and pig were fenced within separate sections to represent cheese, beef, and pork, respectively. The idea originated in Madera, Calif., from Thank-a-farmer, Inc. and was used with permission. The garden is an ongoing cooperative effort between research and extension personnel of Mississippi State University, local county officials, and area schools. The project has garnered support from the Mississippi Cattle Industry Board (start-up and maintenance funds), Heritage Vinyl Products (fencing), D.P. Fence Co. (construction), and Dominoe's Pizza (pizza lunches for the youth). We anticipate at least 1000 school children to visit the “Pizza Farm” each year, and we expect the community to continue to support and take pride in this project.
Networking with Industry for Professional Certification
Authors: Powell MA.
Published: February 2019

The North Carolina Landscape Contractors Association and the North Carolina Association of Nurserymen have cooperated with the NCSU Horticulture Department Extension Landscape Specialist in providing study resources, a demonstration garden, training seminars, and workshops to the landscape and nursery industry. The Certified Plant Professional Program certifies nursery and garden center employees on plant identification and ornamental plant care. Over 350 woody ornamentals, herbaceous perennials, and annuals are in the study guide. A total of 893 folks have been certified since the program began in 1986. County agents teach classes on a regional level. Three tests are given annually. The Certified Landscape Technician's exam is given annually, after many workshops and training sessions are offered. The professional standards of the industry are being improved by the results of the networking with the industry associations.
Master Gardening at a Distance
Authors: Nagel David H.
Published: February 2019

Master Gardener was taught by distance learning through the Mississippi Community College Network (CCN) in 1995 and 1996. Specialists delivered information from a studio on campus while the Master Gardeners were in classrooms in Clarksdale, Fulton, and Moorhead. The interactive video format was well accepted by most of the clientele. Specialists appreciated having to present each lecture once rather than traveling to each location and deliver each topic three times. The use of interactive video is currently being reevaluated due to two major factors: the increased use of CCN by Community Colleges has made scheduling the required weekly 4-hour block very difficult; and, the cost-ineffective method for delivering the training. Current Master Gardener training programs in Mississippi are being implemented through traditional classroom and field methods.
Stabilization of Chimeral African Violet Clones by In Vitro Inflorescence Culture
Authors: Sandall Sharon K. , Lineberger R. Daniel
Published: February 2019

The pinwheel-flowering African violet `Silver Summit', apericlinal chimera, has bicolor flowers with violet-blue corolla segment margins and white central stripes. Several off types were produced during in vitro culture of `Silver Summit'—solid violet-blue flowering from leaf or petiole explants, solid white flowering from petiole core explants, and two reverse pinwheel flowering types. The reverse pinwheel types varied in color; one had deep violet-blue stripes (DR, dark reverse) and the other had lighter stripes of the same color (LR, light reverse). Plantlets derived from inflorescence culture (Murashige and Skoog medium containing 0.1 mg/1 NAA, 0.1 mg/1 BA) were grown on to flowering. Of 55 plants from LR inflorescences, 51 were true-to-type. The remainder were solid violet-blue flowering. Of 64 plants from DR inflorescences, only 8 were true-to-type, 17 were solid violet-blue flowering, one was white flowering, and 38 were mixed flowering. In vitro inflorescence culture can be used to clone pinwheel flowering African violets; however, chimeral stability of the plant produced varies between clones.
The Use of a Variegated Plant to Determine Adaptations to Altered Light Levels
Authors: Pennisi Svoboda V. , McConnell Dennis
Published: February 2019

Variegated Dracaena sanderana plants were grown under 47%, 63%, 80%, and 91% shade cloth. Prior to that, plants were grown under uniform light levels in a greenhouse. Morphological changes which manifested the adaptation to different light levels were not evident until all four leaves present in the apical whorl had expanded. Changes first appeared in a leaf which was 5-15 mm long when plants were placed under the different shade levels. The changes were recognized as alteration in the amount of leaf variegation which gradually changed as new leaves unfolded. After development of four leaves no further morphological changes were apparent. The first `transition' leaf had variegation similar to the preceding leaf and the last `transition' leaf had variegation comparable to the next successive leaf. The amount of variegation was quantified and the changes under different light levels determined. The use of a variegated plant enabled us to readily observe the morphological changes related to light adaptation and showed that a plant is an integrated system which adapts to altered environment over an extended period of time.
Factors Affecting the Resistance of Buddleia Species to the Two-Spotted Spider Mite
Authors: Gillman Jeff , Dirr Michael , Braman Kristine
Published: February 2019

Buddleia species are attractive ornamental shrubs whose major cultural problem is infestations of the two-spotted spider mite. Two factors, drought stress and leaf pubescence, were examined for their effects on spider mite infestations. Drought stress was examined by placing 20 plants into a randomized block design and stressing ten of the plants. No differences in mite life parameters were found, although there was more uninfested area in nonstressed plants. This was probably due to the nonstressed plants' ability to outgrow the spider mite infestation. Leaf texture was examined by placing four female spider mites on 5 leaf disks of 37 cultivars and species of Buddleia and counting the number of eggs laid after 96 hours. There was a strong correlation between leaf pubescence and number of eggs laid. In a second experiment, using a shell vial with a leaf placed underneath the lid and five female spider mites in the vial itself, leaf pubescence was either removed with facial peel or left. In all cases but one, the removal of pubescence increased the number of eggs laid by the spider mites.
Leaf Phenolic Variation Within Apple Tree Canopies
Authors: Garcia M. Elena , Rom C.R. , Murphy J.B. , Kugler K.
Published: February 2019

Light is important in the production of phenolic compounds because key enzymes in phenolic biosynthesis are induced by light, and because products of photosynthesis are used in the synthesis of phenolic compounds. It is known that light intensity decreases with increasing depth in apple tree canopies. The objective of this experiment was to determine how leaf position on a limb affects the total foliar phenolic content. Leaves from `Stark Spur Supreme Red Delicious' on C6 and M26 rootstocks were collected on 28 July and 2 Aug. 1996. Each tree was divided into two sides, east and west. Each side was divided into 3 areas; exterior, middle, and interior. From each area, leaves were collected and PAR, SLW, assimilation, total N, and total phenolics were measured. Leaf position on a limb was a significant parameter for all of the measured variables. PAR, SLW, assimilation, total N, and total phenolics were highest in leaves at the exterior of the canopy. The total foliar phenolic content of the exterior canopy leaves was 20% higher than that found in the interior canopy leaves. There was a significant correlation between SLW and total phenolic content/cm2(r2 = 0.77; P < 0.05). Assimilation may be a limiting factor in phenolics production in apple trees because of the correlation between assimilation and total phenolic content/cm2 (r2=0.56, P < 0.05).
Blueberry Breeding for the Southern United States
Authors: Draper Arlen D.
Published: February 2019

The USDA blueberry breeding program was initiated in 1910 by Dr. F.V. Coville and has been continuous since that time. Plant breeders Drs. G.M. Darrow, D.H. Scott, J.N. Moore, and A.D. Draper have worked with SAES and private growers to develop the majority of cultivars presently grown for commercial production. In the South, major cooperators with the USDA include SAES in Arkansas, North Carolina, Georgia, and Texas. Recently the USDA Station at Poplarville MS, has been instrumental in blueberry cultivar development for the South. Rabbiteye blueberry cultivars make up the majority of blueberry acreage grown in the region. A new type of blueberry, the southern highbush (SHB), has been developed by interspecific hybridization with various Vaccinium species. Late-blooming SHB cultivars have been developed that offer better protection from spring frosts and ripen earlier than the earliest rabbiteye blueberry. Genes required to meet future needs reside within native Vaccinium species. Progress has been made in plant adaptation, disease resistance, fruit quality, and season of ripening. There remains a need for greater plant vigor, insect resistance, and consistent production.
Analysis of Muskmelon Yields From the Tri-State Cooperative Project Involving Seven Locations, Three Years, and Four Cultivars
Authors: Mullinix Benjamin , Batal Dean , et al.,
Published: February 2019

The Tri-State Cooperative Project involved North Carolina, South Carolina, and Georgia. Muskmelons were grown following recommended cultural practices at seven locations in 1985-1987. Two plantings in the spring and again in the fall were made. Cultivars were HILINE, MAGNUM, MAINST, and SUMMET. Locations were for North Carolina: Fletcher (FLT) and Lewiston (LEW); for South Carolina: Clemson (CLM), Charleston (CHL), and Florence (PD); and for Georgia: Attapulgus (ATT) and Plains-Tifton (PLA). Not all locations planted muskmelons during the 12 planting times available except the two spring plantings in 1987. Analysis of each location revealed that years were significant except for ATT; seasons except for ATT; plantings except for FLT; and cultivars except for CHL and LEW. Season × cultivar was significant only for FLT and PLA. LEW and ATT had the highest yields, while FLT had the highest variance. Spring plantings had higher yields. MAINST had the highest yield among the cultivars. Analysis of the location by cultivar means revealed that locations were significant (P = 0.01) and cultivars were significant (P = 0.05).
Quality and Marketable Yield of Baby-style Carrots as Affected by Root Size, Population Density and Lines of Seed/Bed
Authors: Lazcano Carlos A. , Dainello Frank J. , Pike Leonard M. , Miller Marvin E. , Brandenberger Lynn , Baker Larry R.
Published: February 2019

Baby-style carrot Daucus carota Mill. cv. Caropak was studied under four population densities, three different numbers of lines per bed, and harvested under three root size harvest parameters in the Rio Grande Valley of Texas. Four phases in the baby-style carrot process were evaluated. Length of the roots at harvest and projected values for total waste and marketable yield were estimated. Length was affected by root size at harvest, the most desirable root length occurred when harvested at 25%-35% roots diameter >2 cm. The longer roots (16.55 cm) were in the treatments with 6 seed lines per bed and 197 plants/m2. Population density affected the fresh and cut weight in the baby-style carrots process with the highest weight at 321 plants/m2. Percent of cut waste was the same at the three-root size at harvest with 21.65% of crowns and tips cut. The percent of graded waste was lowest when harvested at the biggest root size, 14.23% and four seed lines per bed produced the highest waste with 18.14. Seed lines per bed affected the quality of the roots in the graded step. Based on a 40% peeling waste projection the lowest total waste was estimated at 59.69% and the highest projected marketable yield of 19.4 t/ha of final product when roots were harvested using the 25%-35% root diameter parameter. Root size at harvest is the main factor affecting projected marketable yield of baby-style carrots in South Texas.
Seed Storage Media Effects on Persimmon Germination
Authors: Dunwell Winston C. , Wolfe Dwight E.
Published: February 2019

Common persimmon, Diospyros virginiana, a medium to large, attractive native tree of narrow habit, is potentially a valuable landscape tree due to its tolerance of diverse environmental conditions. Previous work by the authors demonstrated that seed stored in perlite or peat moss had a higher percent germination following cold storage than seed stored without media. Seeds were prepared for cold storage by two methods: 1) moist seed—cleaned (cap, skin, and the easily removed pulp discarded), and (2) dry seed—cleaned, dried for three days, and the remaining pulp removed. The media were either dried or moistened, but not saturated. The treatments were: 1) moist seeds; 2) dry seeds; 3) moist seeds in dry perlite; 4) moist seeds in moist perlite; 5) dry seeds in dry perlite; 6) dry seeds in moist perlite; 7) moist seeds in dry peat moss; 8) moist seeds in moist peat moss; 9) dry seeds in dry peat moss; 10) dry seeds in moist peat moss. Seed was stored at 4.4° for 142 days. Germination of seed stored in dry perlite was not significantly different from that stored in moist perlite or peat moss, but dry peat moss significantly limited germination regardless of seed preparation.
Using Phenomenological Interviewing: A Qualitative Research Method for People-Plant Studies
Authors: Hamilton Susan Wilson
Published: February 2019

Phenomenological interviewing is a research approach used extensively and successfully in the social sciences and has implications for those working with people-plant interactions. Although many research methods are available for horticulturists to use in obtaining information about a target audience, most methods used (e.g., surveys and questionnaires) are quantitative in nature in that they provide numerical data on statistical generalizable patterns. Phenomenological interviewing allows investigators, through open-ended interview questions, to obtain more in-depth data than traditional quantitative techniques. Transcribed interview tapes become the data from which analysis and interpretation follows. “Coding” the data by searching for words, phrases, patterns of behavior, subjects' ways of thinking, and events which are repeated and stand out classify and categorize the data helping with its interpretation and write up. Writing up such data must develop how you interpret what you found by carefully integrating themes that support a thesis and create or augment theoretical explanations. This research method allows investigators to understand and capture the points of view of the participants without predetermining those points of view through prior selection of questionnaire or survey categories.
Relationship between the Effects of Salinity on Seedling Leaf Area and Fruit Yield of Six Muskmelon Cultivars
Authors: Franco José A. , Fernández Juan A. , Bañón Sebastián , González Alberto
Published: February 2019

Six muskmelon (Cucumis melo L.) Galia-type cultivars (`Delada', `Gallicum', `Galor', `Melina', `Regal' and `Revigal') were tested for salt tolerance at the seedling stage and during growth in the field. Three levels of salinity (ECW 2.5 (control), 5.0 and 7.5 dS·m-1), established by adding NaCl to fresh water, were used. The effect of salinity on seedling growth was assessed by measuring the total leaf area 36 days after sowing. `Melina' was the most tolerant at this stage and during subsequent growth in field, with a relative seedling leaf area of 60 and a relative yield of 66 at 7.5 dS·m-1 salinity, both expressed as a percentage of the values obtained at the control level of salinity. `Delada' was the most sensitive to the highest level of salinity at both stages, with relative seedling leaf area and yield of 51 and 56, respectively. For all cultivars, a highly significant correlation (r = 0.99) was established between the influence of salinity on seedling leaf area reduction and on decrease in yield during field culture. The results indicate that the reduction in seedling leaf area can be a good selection criterion to facilitate rapid screening for salt tolerance in muskmelon.
A Direct Headspace Sampling Technique to Rapidly Measure Low Boiling Point Volatile Terpenoids in Carrots
Authors: Yoo Kil Sun , Pike Leonard M. , Hamilton Brian K.
Published: February 2019

A simple and fast method for measuring low boiling point (LBP) volatile terpenoids in carrots (Daucus carota L.) was developed by using a direct headspace sampling technique. Seven LBP terpenoid compounds were separated with high sensitivity and consistency via gas chromatography. High boiling point terpenoids above terpinolene were not well characterizable. Standard compounds showed highly linear responses up to 10 μg.g-1, with a detection limit of 0.01 μg.g-1. We confirmed that high α- and β-pinene and/or total terpenoids contributed to harsh or oily flavors. Up to 40 samples can be analyzed in an 8-h day using this method, compared to 10 samples using previous methods.