bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comparison of Alternative Weed Management Strategies for Field-grown Specialty Cut Flowers in Maine
Authors: Chapin Diana George , Stack Lois Berg
Published: February 2019

A 2-year field study was initiated in May 1994 to show the effects of alternative weed control methods on weed suppression and cut flower yield. Cultural and economic analyses evaluate the feasibility of various management decisions. Gomphrena globosa cv. Woodcreek Pink seedlings were transplanted at 12-inch spacings with the following treatments: 10 mm chopped straw mulch, 10 mm shredded paper mulch, 1.25 mm black plastic mulch, bare soil with postemergent herbicide (Glyphosate) and bare soil with hand weed control. First-year results of the study show weed control was statistically equal between plastic, herbicide, and hand control. These methods provided significantly better barriers to weed growth than shredded paper and oat straw. Economic analyses show variation in the cost efficiency of these methods, however. It is expected that the results of the first year will be corroborated in 1995 for the herbicide, hand control, and plastic treatments, but will reflect change in the chopped straw and shredded paper treatments due to improved focus on experimental design and material selection.
Comparison of Paclobutrazol Drench, Spray, and Spike Applications for Height Control of Foliage and Flowering Baskets
Authors: Lang Harvey J. , Wilkerson Don C.
Published: February 2019

Experiments were conducted to determine the effectiveness of paclobutrazol in solid spike form as compared to foliar spray or medium drench applications for height control of several foliage and flowering plants grown in 8-inch or 10-inch hanging baskets. Paclobutrazol was applied as either a 20 or 40 mg·liter–1 foliar spray, 1 or 2 mg·liter–1 medium drench, or 200 or 400 mg·liter–1 spike insertion per basket. Begonia × tuberhybrida `Nonstop Apricot' and Begonia × hiemalis `Barbara' treated with paclobutrazol were significantly shorter than nontreated controls. Drench applications were more effective than either spray or spike treatments for both species, with Hiemalis begonia showing severe dwarfing at both the 1 and 2 mg·liter–1 drench. Paclobutrazol treatments did not significantly affect flower number for either species. Syngonium podophyllum `White Butterfly' and Epipremnum aureum showed similar trends as the begonias; however, relative reductions in height were not as great. Plants appeared to be slightly less stretched than nontreated plants.
High-resolution Analysis of the Effect of DIF and Growth Regulators on Stem Elongation in Zinnia
Authors: Neily Will G. , Hicklenton Peter R. , Kristie David N.
Published: February 2019

Instantaneous stem elongation rates (SER) in zinnia (Zinnia elegans cv. Pompon) treated with daminozide (B-Nine) or gibberellic acid (GA3) were recorded in 3 DIF regimes (+5, –5, 0; daily average 18.7C). Two developmental stages were chosen for study: Stage 1 was vegetative growth before flower bud formation Stage 2 was the period before anthesis. At both stages, patterns of SER and total diurnal growth were influenced by DIF regime. The application of GA3 increased SER in a more or less additive manner over all phases of the diurnal growth cycle and daminozide similarly reduced SER. Neither GA3 or daminozide application transformed growth patterns to match those of positive or negative DIF plants, respectively. Instead. the growth regulators only enhanced or reduced total diurnal growth without modifying the effects of DIF. This suggests that DIF can influence stem elongation growth in a manner which is independent of the effects of gibberellin.
Evaluating Paper Sludge in Container Media Used for Mum Production
Authors: Tripepi Robert R.
Published: February 2019

Paper sludge is a fibrous material that may be suitable as a replacement for peat moss in potting media. The goal of this study was to compare the growth of potted `Iridon' mums (Dendranthema × grandiflora Tzvelev.) grown in sludge-amended media against that of plants in two peat-based commercial mixes. Paper sludge from a newsprint mill was composted 6 weeks. Plants were grown in a European pot mum regime with three rooted cuttings planted in square 10-cm pots containing either a commercial mix or a sludge-amended medium [75% sludge: 15% perlite: 10% vermiculite; or 50% sludge: 33% peatmoss: 17% perlite (by volume)]. Plants were grown for 12 weeks and not disbudded before plant growth indices were determined. Mums grown in sludge-amended media appeared similar to those grown in the commercial mixes. Plants grown in either sludge-amended medium were slightly shorter (1.5 cm) and narrower (2.5 cm) than those grown in the commercial mixes. In addition, mums grown in sludge-amended media produced eight fewer flowers and 4 g less shoot dry weight (per pot) compared to plants in commercial mixes. Composted paper sludge appears to be suitable for production of `Iridon' pot mums, even though plants grown in this material grew slightly less than those in commercial media.
Characterization of Substrate Hydraulic and Physical Properties as Related to Irrigation, Plant Growth, and Water Transport
Authors: Fonteno William C. , Drzal Matthew S. , Cassel D. Keith
Published: February 2019

The influence of substrate physical properties on water transport and plant growth must be known if irrigation water use efficiency is to be improved. Three fundamentally different substrates were examined: 1 peat moss: 1 vermiculite (v/v), 3 pine bark: 1 peat: 1 sand, and 1 mineral soil: 1 peat: 1 sand. Capacity analyses included total porosity, container capacity, air space, available water and unavailable water. Water transport was characterized by saturated and unsaturated flow analyses. A new method, Pore Fraction Analysis, was developed to characterize substrate pore structure into fractions based on function with the substrate. This method is based on soil moisture retention curves, pore size distributions, and average effective suction at container capacity (AEScc) This method is offered to expand the traditional terms of macropore and micropore into new definitions: macropores, mesopores, micropore, and ultramicropore; each based on a range of pore sizes and functions. Computer simulation models of air and water profiles were run on several container sizes with the three test substrates. Pore fraction analysis indicated that under traditional production practices macropores indicate the volume of a substrate that be filled with air at container capacity, the mesopore fraction effectively fills and drains with daily irrigation, the micropore fraction functions as a measure of water reserve, while the ultramicropores contain water unavailable to the plant.
Transplant Cell Size Affects Early and Total Yield of Muskmelon
Authors: Maynard E.T. , Vavrina C.S. , Scott W.D.
Published: February 2019

Muskmelon (Cucumis melo L. cvs. Superstar and Mission) transplants were grown in seedling flats with individual cells ranging in volume from 7 to 100 cm3. The smallest cells were in a 338-cell polystyrene flat 33 cm wide × 66 cm long × 4.75 cm deep; the largest cells were in a 32-cell plastic flat 30.5 × 50.8 × 6.5 cm. The study was conducted in Florida and Indiana during the 1993 and 1994 growing seasons. Seedlings of uniform age were transplanted to the field and grown to maturity using standard cultural practices. Early yield of `Superstar' muskmelon, measured as number of fruit per plot or percentage of total yield, increased as transplant cell volume increased. In one trial, plants from 7-cm3 cells produced no early yield, while plants from 100-cm3 cells produced 40% of the total yield in the first three harvests. In three of the four trials, total yield of `Superstar' increased as cell volume increased. Marketable early yield of `Mission' muskmelon, measured as number or weight per plot, increased as cell volume increased in three of four trials. In Florida, total yield of `Mission' also increased as cell volume increased. Size of `Superstar' fruit was not influenced by cell volume. In Florida, size of early `Mission' fruit increased as cell volume increased.
Quality Variability of Prairie and “Garden” Wildflower Seed Obtained from Commercial Sources
Authors: Dana Michael N. , Kemery Ricky D.
Published: February 2019

Interest in direct-seeding establishment of wildflowers as a component of landscape planting has continued to increase. Seed may be very expensive. Information is needed on the quality of seed available to consumers and the landscape industry. The goal of this work was to assess the level and consistency of seed quality available from the wildflower seed production/marketing industry. Eleven species of native prairie forb wildflowers and eight species of “garden” wildflowers from seven companies were purchased in 1992 and 1993 and subjected to germination testing. Germination procedures were those of AOSA where available, or generalized from the literature when no guidelines existed. Results showed significant variation among wildflower species, among companies supplying the same species, and over the two seed years tested in the study. These data reinforce the need for seed quality testing and reporting as a part of the sales of wildflower seed.
Respiratory Byproduct—Ethanol: An Indicator of Lettuce and Sweet Corn Seed Quality
Authors: Kataki P. , Taylor A.G.
Published: February 2019

The production of ethanol under anaerobic and aerobic conditions is suggested as a sensitive indicator of seed aging. Seeds of sweet corn (Zea mays L. `Jubilee') and lettuce (Lactuca sativa L. `Salinas') were aged at 75% relative humidity and 45C to obtain five aged seed lots and compared to a nonaged control sample. The percent germination decreased while percent abnormal seedlings initially increased with seed aging. Anaerobic treatments were induced either by immersing seeds in distilled water for sweet corn or in a solution of 50 mM glucose and 5 mM KPO4 buffer adjusted to pH 5.6 for lettuce. Aerobic treatments were performed by placing seeds in a plastic chamber filled with a known amount of glass beads sufficiently moistened to allow imbibition. Ethanol was measured after 12 and 24 hours from lettuce and sweet corn, respectively. Aqueous extracts were analyzed by immobilized enzyme technology and verified by gas chromatography. Anaerobiosis induced large amounts of ethanol production compared to aerobic treatments. The amount of ethanol decreased with seed aging duration under anaerobic conditions while these trends were generally reversed under aerobic conditions. The ratio of ethanol produced under anaerobic compared to aerobic conditions was best able to separate differences in seed quality due to aging.
Nitrogen Assimilation of Micropropagated Strawberry Plantlets during the Transition from Heterotrophy to Photoautotrophy
Authors: Aquin S. , Desjardins Y. , Vézina L.-P.
Published: February 2019

A study was conducted to determine the implication of nitrate reductase (NR) and glutamine synthetase (GS) during the transition of micropropagated plantlets from heterotrophy to photoautotrophy to document how nitrogen metabolism interfaces with photosynthetic and anaplerotic CO2 fixation. The activity of the two enzymes was determined in different tissues at different organogenic stages during the development of plantlets transferred onto rooting media containing varying quantities of sucrose. Under 3% sucrose, NR activity was much higher in leaves than in crown tissues. When roots are initiating, there is a shift in the proportion of nitrate reduction from leaves to crown. As roots mature, the proportion of nitrate reduction increases in roots. Similar trends were observed under 5% sucrose. In contrast, under 1% sucrose, a higher proportion of the nitrate is reduced in the leaf tissues throughout the culture period. This suggests that nitrate is reduced mainly in leaves in photoautotrophic plantlets, while it is reduced in crowns and root tissues for mixotrophic plantlets. In general, the GS activity follows the pattern of NR, but is always in excess, to enable rapid assimilation of ammonium derived from metabolism and medium absorption.
High Efficient Procedure of Agrobacterium-mediated Transformation of Cultivated Tomato (Lycopersicon esculentum)
Authors: Le Van Quy , Overney Serge , Quoc Binh Nguyen , Yelle Serge
Published: February 2019

Tomato is one of the most important crop species where the introduction of foreign genes is expected to have a major impact on agriculture. Several transformation methods exist that rely on the cocultivation of various tissue or organ explants. However, tomato is still considered more difficult to transform than species such as Petunia hybrida and Nicotiana tabacum and can show widely varying success rates. Using cotyledonous explants, we propose a highly efficient procedure of Agrobacterium-mediated transformation and regeneration of an agricultural cultivated tomato (L. esculentum cv. Summerset). Results showed that up to 90% of the cotyledons generated callus within 3 weeks (1 to 5 calli/cotyledon) and 50% of them regenerated shoots in another 3 weeks. Finally, it resulted in 50 to 100 independent transgenic plants per 100 inoculated explants within 10 weeks. These results are at least 40% more efficient than those of already published protocols. Moreover, up to 95% of the regenerated plants that form vigorous de novo roots under the antibiotic selection tested positive for the GUS assay. Screening by PCR for the presence of the T-DNA genes gave the predicted DNA fragment bands. This high efficiency procedure was mainly achieved by 1) an adequate optimization of the hormone composition and concentration of the successive culture media; 2) the fresh explant wounding before the Agrobacterium infection (important for optimal cell transformations); 3) the explant position, inside down for callus induction and coculture period, and upside down for the selection and organogenesis period (important for antibiotic selection).
Response of Adult Black Walnut (Juglans nigra L.) Nodal Explants on DKW and LP Media
Authors: Khan Sagib B. , Preece John E. , Taylor Bradley H. , Van Sambeek J.W.
Published: February 2019

Branch tips (30 to 40 cm long) of adult black walnut were forced in a half-strength solution of Long and Preece medium (LP) salts (minus iron) plus 1 mM 8-hydroxyquinoline citrate (8-HQC). The resulting softwood shoots were surface-disinfested and cut into 1.5-cm-long nodal segments. Explants were placed on two media: Driver and Kuniyuki Walnut medium (DKW) or LP with four plant growth regulator combinations: 5 μM BA with 0.05 μM IBA, 10 μM BA, 1 nM TDZ, or 10 nM TDZ in a factorial arrangement. Gelrite was used as the gelling agent. Explants were transferred to fresh medium on days 1, 3, 5, and 7 after initiation, then weekly. Data recorded 60 days after culture initiation showed more and longer shoots and leaves, greater explant diameter, more green (living) tissue, and less exudation per explant on LP than on DKW. Greatest explant and shoot length were observed when the medium contained 10 nM TDZ. BA (10 μM) and LP were best for long-term maintenance of cultures
Visualization and Analysis of Air Currents in the Plant Tissue Culture Vessel
Authors: Omura Y. , Kitaya Y. , Kozai T.
Published: February 2019

Air currents, and consequent diffusion processes, in the plant tissue culture vessel are slow and limit photosynthesis, transpiration, and uptake of water and nutrients by in vitro plantlets. Air currents in Magenta-type and Mayonnaise bottle-type culture vessels were visualized using fine particles of feathery crystal of metaldehyde [(CH3CHO)4] as tracers. Pictures of visualized air currents were recorded by the video camera. Air current speeds in the culture vessel were determined by analyzing the changes in video pictures with time. Air current speed around the culture vessel was set at 0.1 and 1.0 m–s–1. Shortwave radiation flux density on the shelf was varied between 0 and 34 W–m–2. Shortwave absorptivity of the medium was 44% for agar medium and 97% for agar medium containing activated charcoal. Under a shortwave radiation flux density of 10–34 W–m–2, the upward air currents were observed at the central part of the culture vessel and downward air currents were observed near the inside walls of the culture vessel. The upward air current speed was affected by air current speed around the culture vessel, shortwave radiation flux density, and shortwave absorptivity of the medium. Under shortwave radiation flux density of 34 W–m–2, the upward air current speed in the culture vessel was ≈4 times greater with 1.0 m–s–1 air current speed around the culture vessel than with 0.1 m–s–1.
Growth and Nutrient Uptake of Cell Suspensions of Thlaspi caerulescens and Brassica napus Treated with the Heavy Metal Zinc
Authors: Bundithya Weenun , Kitto Sherry L.
Published: February 2019

Thlaspi caerulescens (Brassicaceae), known as a Zn hyperaccumulator, is able to accumulate and tolerate Zn at high concentrations in its biomass. Cell suspension cultures of Thlaspi caerulescens J et C Presl and B. napus `Westar' have been initiated to study the effect of high Zn concentrations on growth and nutrient uptake. Preliminary studies determined the optimal conditions for subculturing and maintaining cultures. Cell suspensions grew best on Murashige and Skoog medium supplemented with B5 vitamins and 1 mg 2,4-D/liter at 0.4 g/25 ml inoculation density, and with a 2-week subculture period. In an initial experiment, cell suspensions were cultured in media containing 1.96 ppm Zn (basal) or 49 ppm Zn (25x). Media and tissue samples were collected at days 0, 4, 7, 10, and 13, and their nutrient content was analyzed by ICP-AES. Thlaspi and Brassica cell suspensions grew equally well on both media. For both species, uptake patterns of Ca, K, Mg, Mn, and P were not significantly different between the two media; however, >97% of the P was taken up within 2 weeks. Zinc concentration was reduced during the first 4 days (lag phase) in the high-Zn medium, with 27% and 41% taken up by the Thlaspi and Brassica cultures, respectively. Thlaspi took up significantly less Zn than did Brassica. By day 13, Thlaspi and Brassica tissue collected from the high-Zn medium contained 10x and 32x, respectively, more Zn when compared to tissue grown on basal medium.
Spontaneous and Induced Changeableness and Accumulation of Phenol Compounds in Cell Culture of Alhagi kirghisorum
Authors: Sapko O.A. , Shamina Z.B.
Published: February 2019

Our studies concerned the peculiarities of phenol compound (PhC) formation in cultivated in vitro cells of Alhagi kirghisorum. To isolate cell strains with a high level of PhC biosynthesis, cells were sown on a medium containing parafluorophenylalanine (PFPA). To increase the number of resistant cell lines, the cells were treated with N-nitrose-N-methylurea (NMU). Four groups of individual clones were obtained: spontaneous, induced NMU, and resistant to PFPA. These clones differed in their intensity of growth, color, consistence, quantity, and PhC composition, as well as in their biological activity. Maximum differences were found in the clones with induced resistivity. In this group, clones with PhC content were at the level of control cells (40%), with high (33%) and low level of biosynthesis (27%). The PhC content in two more productive lines was 3.3 and 4.2 times higher than in controls. The induced NMU clones and clones with spontaneous resistivity to PFPA had biosynthesis levels similar to the control or 3 to 4 times lower than the latter. The biological PhC activity of a clone was tested by its effect on the processes of protein biosynthesis in a system without cells from rabbit reticulocytes. Eleven clones were found, the total PhC fractions of which in 40% to 99% inhibited protein biosynthesis.
Mutagenesis and Tissue Culture for Selecting Phytopthora cactorum-resistant Strawberry (Fragaria xananassa) Plants
Authors: Jain S. Mohan , Lasus Carola , Alen Karita
Published: February 2019

The aim of this study was to isolate Phytopthora cactorum-resistant strawberry plants, regenerated from gamma-irradiated explants on a shoot regeneration medium. Three gamma doses (0, 5, 10, 15 krad) were used to irradiate strawberry axillary buds taken from in vitro-grown plants. After irradiation, axillary buds were cultured on a shoot regeneration medium containing 0.75 mg BA/liter and 0.4 mg IBA/liter. Shoot regeneration occurred mainly from axillary buds irradiated with 5 and 10 krad. The highest dose (15 krad) produced few shoots. The shoot regeneration rate was highest at the 50-krad dose. All the regenerated plants were transferred in the greenhouse. The crude extract of P. cactorum, isolated from the strawberry field, was prepared in sterile water; 1 ml of it was put directly in the center of the crown of each of 400 regenerated plants. After 2 weeks, leaves of most of the plants wilted. Only 20 plants survived the first round of selection; they grew slowly when compared with the control and also showed some tolerance to drought. Further investigations are in progress to reconfirm the resistance of selected putative disease-resistant strawberry plants.
Post-translational Regulation Using Anti-peptide Antibody of 22-Kilodalton Potato Proteinase Inhibitors
Authors: Suh Sang-Gon , Moon Yong-Sun , Hannapel David J.
Published: February 2019

The 22-kDa potato proteinase inhibitors (22-kDa PPI) are synthesized as a preprotein with a hydrophobic signal sequence of 40-residue amino acids. The amino-terminal amino acid sequence (10-mer amino acids: 18-Ala-Phe-Ala-Arg-Ser-Phe-Thr-Ser-Glu-Asn-27) of signal peptide of 22-kDa PPI was synthesized. The 22-kDa PPI signal peptide specific anti-peptide antibodies were raised in New Zealand white rabbits against the 22-kDa PPI synthetic signal peptide. Immunoblot and Northern blot analysis were performed by using 22-kDa PPI anti-peptide antibody and cDNA probe, p34021, which codes for the 22-kDa PPI, respectively. In this paper, we determined the process of the 22-kDa potato proteinase inhibitor in tuber and wounded leaves.
PCR Amplification of the Mitochondrial DNA Sequence Specific to the Male-sterile and Normal Cytoplasm in Onion
Authors: Satoh Yutaka , Ito Kimio , Mikami Tetsuo
Published: February 2019

We compared the transcriptional properties of mitochondrial DNA (mtDNA) from a pair of male-sterile (S cytoplasm)/maintainer (N cytoplasm) lines together with the nuclear-restored plants. The transcriptional patterns of the mitochondrial genes, cob and cox1, were different between N and S cytoplasm. We cloned and sequenced the cob gene from both N and S onion. The Scob gene diverged from the Ncob gene 56 bp 5' to the initiation codon. This upstream region of the Scob gene was homologous to a part of ORF1708 of the tobacco chloroplast DNA. We designed primers to amplify the upstream regions of the cob by PCR. A 414-bp DNA fragment was amplified from the total DNA of `2935A' (S cytoplasm) and a 130-bp DNA fragment was amplified from that of `2935B' (N cytoplasm) using a pair of primers specific to S cytoplasm and nor cytoplasm, respectively.
Effects of the Time of B Application on Almond Tissue B Concentration and Fruit Set
Authors: Nyomora Agnes M.S. , Brown P.H.
Published: February 2019

Previous work in our laboratory demonstrated that B promotes flowering, fruit set, and yield in almond. A positive response of almond tissue B concentration, fruit set, and yield to B application was observed. Positive correlations between tissue B concentration with fruit set or yield were found when B was applied at 0–1.67 kg B/ha. An investigation was undertaken to test whether the time of B application had a significant effect on B concentration and yield in almond. Solubor (20.5% B) was applied at 0.8 and 1.67 kg B/ha during fall (September), winter (December), and spring (February) to `Butte' (pollinizer) and `Mono' (pistil donor). Results show that for most attributes, September application was more effective than spring and winter. `Butte' was more responsive to B application than `Mono'.
Effect of Urea, Some Micronutrients, and Growth Regulator Foliar Sprays on the Yield, Fruit Quality, and Some Vegetative Characters of Washington Navel Orange Trees: Fruit Physical and Chemical Properties
Authors: Akl Ahmed M. , Eid Abdel-Fattah M. , Hegab Mohamed Y.
Published: February 2019

This part of the investigation studied the effect of foliar spraying with urea (0.5%); a mixture of Zn (0.4%), Mn (0.3%), Fe (0.5%), and Cu (0.3%) in sulphates (from 23% Zn, 28% Mn, 19% Fe, and 30% Cu, respectively); and two growth regulators (GA3 at 25 ppm and α-NAA at 10 ppm); as well as number and date of sprays on fruit volume, percentage of pulp, juice acidity, TSS, reducing and total sugars, TSS: acid ratio, and vitamin C content. The results showed that Washington Navel orange trees receiving urea, micronutrients, or both gave fruit with significantly larger volume compared with the control, but the treatment including both resulted in the highest values for fruit volume in 1991–92 and 1992–93 seasons. GA3 sprays gave the highest fruit volume, followed by NAA, while the water spray (control) gave the lowest values for this trait. Two sprays of urea, micronutrients, and GA3 resulted in the highest fruit volume in 1991–92 and 1992–93 seasons. The effect of different treatments on pulp percentage were slight and mostly insignificant in the two experimental seasons. Spraying urea, micronutrients, or both slightly reduced juice acidity and increased TSS, sugars, and vitamin C contents, as well as TSS: acid ratio; however, both of them together was more effective in this respect. Conversely, either GA3 or NAA caused an appreciable increase in acid content in the juice, but decreased the other determined constituents, except vitamin C, which increased.
Comparison of Disease Forecasting for Early Blight Control on Stake Culture Versus Ground Culture Fresh-market Tomatoes in New Jersey
Authors: Maletta M.H. , Cowgill W.P. , Tietjen W. , Nitzsche P. , Johnston S.A.
Published: February 2019

The number of fungicide applications for tomato early blight control required by three disease forecasting systems—FAST, Pennsylvania State Univ., CUFAST, Cornell Univ., and TOMCAST, Ridgetown College, Ont.—was less than the number required following a weekly schedule. Foliar disease was significantly lower for all schedules compared to the untreated control. Cultural treatment had no significant effect on disease control, but disease incidence was significantly lower for stake culture than ground culture treatments. Total yield was not affected by cultural treatment, was significantly increased by a weekly fungicide application schedule, and was not appreciably different among the forecast fungicide application schedules. Marketable yield was significantly higher for stake culture than ground culture treatments and was significantly increased by all fungicide application schedules compared to the untreated control. Marketable yield was significantly lower for certain forecast schedules compared to the weekly schedule. Potential cost savings of $379 per acre and pesticide reductions of 33 lbs a.i. per acre for the season were calculated. Chemical name used: tetrachloroisophtalonitrile (chlorothalonil).
Tillage and Cover-cropping Affect Weed Populations and Yield of Broccoli and Cauliflower
Authors: Bowen Pat
Published: February 2019

Research was conducted to determine whether tillage in the fall rather than spring could be used to prepare fields for transplanting broccoli and cauliflower crops. Because fall-tilled soils are prone to erosion by winter rains, the effects of a fall-planted barley cover crop were also determined. Trifluralin was applied to the spring-tilled plots, according to grower practice. Herbicide treatments applied to fall-tilled plots were early and/or late applications of glyphosate and napropamide following early and late glyphosate applications. Weed emergence was generally increased by the barley cover crop, but the species depended on which herbicides were applied. Napropamide reduced the emergence of some weed species, whether or not a cover crop was grown. Yield of broccoli was reduced by the cover crop, and was highest in fall-tilled plots that received two glyphosate treatments. Yield of cauliflower was highest in spring-tilled plots that were cover-cropped. In fall-tilled plots, cauliflower response to the cover crop and herbicide treatments was inconsistent.
Grower Contributions to the Early Stages of Crop Nutrient Trials with Vegetables
Authors: Lamberts Mary , O'Hair Stephen K. , Carranza Juan , Hochmuth George , Hanlon Edward
Published: February 2019

Trials to determine crop nutrients for four vegetable crops grown on the limestone soils of Dade County, Fla., have been conducted in growers' fields to duplicate commercial growing conditions. This has increased grower participation in the experimental process. The four vegetable crops are snap beans, Irish potatoes, sweet corn, and malanga (a.k.a. yautia or tannia, Xanthosoma sagittifolium Schott). The discussion will focus on grower participation in various critical decision-making activities: a) location of plots in a commercial field, b) placement of fertilizers, c) possible problems with Restricted Entry Intervals, d) harvest determinations, and e) grading criteria and quality assessment.
Cropping Efficiency of Young `Fuji' Apple Trees
Authors: Andrews Preston K. , Collier Margaret L.
Published: February 2019

Effects of crop load and time of thinning on productivity of young `Fuji'/M.9 apple trees were tested by hand blossom (B) or fruit (F) thinning to two crop densities (fruit number/trunk cross-sectional area). Heavy (H) crop densities resulted in higher yields in both 2nd and 3rd leaf than light (L) crop densities. Time of thinning had no effect on yields in either year. In the 2nd leaf, fruit size was largest from trees B thinned to L crop densities, and smallest from trees F thinned to either crop density from mid-June through harvest. Both 1° and 2° vegetative growth were greatest in noncropped trees, intermediate in trees with L crops, and least in trees with H crops. Noncropped 2nd-1eaf trees had the highest flowering indices (flower clusters/100 total buds) the following spring and H cropped trees had the lowest. The flowering index was higher when trees were B thinned in the 2nd leaf than when F thinned. In the 3rd leaf, fruit size was largest when borne on weak upright shoots, intermediate on spurs, and smallest on 1-year-old terminal wood. Fruit on spurs had the highest incidence of sunscald (17%) and fruit on weak upright shoots the lowest (8%). Previous-season crop densities affected current-season's vegetative and fruit growth.
Nondestructive Estimation of Pear Fruit Weight Using a Regression Model
Authors: Garriz Patricia I. , Alvarez Hugo L. , Colavita Graciela M.
Published: February 2019

Nondestructive estimation of pear fruit weight is an important horticultural element for size prediction, particularly when repeated measurements of the same tree must be made without affecting growth. Our objective was to develop a method for determining pear fruit weight (W) using models correlating it with fruit maximum diameter (D), an easily measured dimension. A mature crop of Pyrus communis L. cv. Williams was studied at our Experimental Farm. Five trees were selected at random and fruits were sampled at weekly intervals, starting in September, 21 days after full bloom (DFB) and ending in January, 142 DFB, during three growing seasons (1991–92, 1992–93, and 1993–94). Regression equations were developed using SYSTAT procedure. Data for three years were amalgamated because analysis showed that their curves did not differ. W vs. D was best fitted to the model W = 0,8236 D2.778 R2 = 0,98. Variability of W and D increased with fruit growth.
A Taste-test Comparison of Organic and Conventional Greenhouse Tomatoes
Authors: Wees David
Published: February 2019

`Caruso' tomatoes were grown in a glass greenhouse in Winter and early Spring 1991. All plants were grown in 16-liter nursery pots. Half the plants were grown in a conventional peat-lite medium (Profi-mix) and were fertilized with synthetic water-soluble fertilizer containing micronutrients and (in ppm) 187 N, 46 P, 278 K, 177 Ca, and 48 Mg. The other plants were grown in a potting medium composed of 1 mature compost (chicken manure and leaves): 1 loam: 2 vermiculite (by volume); this medium was amended with 1.5 kg bone meal (2N–10P–0K) and 3 kg dolomitic lime/m3. The “organic” treatment was fertilized with a fish emulsion solution containing (in ppm) 150 N, 13 P, and 25 K. The experiment was repeated in 1992 with `Capello'. In both years, fruit were harvested around the half-ripe to three-quarters ripe stage. All insect control was with insecticidal soap and bio-control agents. A blind taste test was conducted on campus in both years. In 1991, of 70 participants, 73% preferred the “conventional” tomatoes, 20% preferred the organic tomatoes, and 7% expressed no preference. In 1992, of 105 participants, 67% preferred the “conventional” tomatoes, 24% preferred the organic tomatoes, and 10% expressed no preference.
Biosolids–Yard Trimming Composts Increases Bell Pepper (Capsicum annuum L.) and Cucumber (Cucumis sativus L.) Yields
Authors: Roe Nancy E. , Stoffella Peter J.
Published: February 2019

Composts may improve crop growth in sandy soils. A biosolids-yard trimming compost (C) was incorporated into sandy soil at 134 t·ha–1 (49.7% moisture) before applying polyethylene mulch. Fertilizer (F) was applied at 0%, 50%, and 100% of the grower's rate (71N–39P–44K t·ha–1 broadcast and 283N–278K t·ha–1 banded in bed centers). `Elisa' pepper transplants were planted 20 Jan. 1994. Marketable fruit weights were 20, 31, and 32 t·ha–1 without C and 30, 35, and 32 t·ha–1 with C for 0%, 50%, and 100% F, respectively. Pepper fruit weights increased with increasing F rates and were higher in plots with C than without C. Without removing mulch, `Thunder' cucumbers were seeded on 26 Sept. 1994. Marketable fruit weights were similar at the three F levels, but were 23 and 27 t·ha–1 without and with C, respectively. One application of C significantly increased bell pepper yields and a subsequent cucumber crop.
Growth and Nutrient Status of Containerized Shrubs Grown in Composts Containing Waxed Corrugated Cardboard and Other Organic Wastes
Authors: Raymond D.A. , Chong C. , Voroney R.P.
Published: February 2019

Four containerized deciduous ornamental shrubs, [silverleaf dogwood (Cornus alba L. `Argenteo-marginata'), red-osier dogwood (Comus sericea L.), ninebark (Physocarpus opulifolius L.), and deutzia (Deutzia gracilis L.)] were grown in 12 composts containing (by volume) spent mushroom substrate (50%), waxed corrugated cardboard (WCC; 0%, 25%, or 50%), and/or pulverized wood wastes (PWW; 50%, 25%, and 0%). Supplemental N as poultry manure and/or soybean wastes was added to some composts. Growth (shoot dry weight, average of two seasons) of all species was better or similar in most composts compared with two controls (100% pine bark and 80% pine bark: 15% peat: 5% sand). Deutzia grew best in 50% WCC composts and other species in 25% WCC composts. Porosity characteristics of the composts were acceptable for container growing (50% to 60% total; 25% to 30% aeration). Total soluble salts were initially high and potentially phytotoxic, particularly in the 50% WCC composts but were quickly leached and resulted in no injury to plants. There were no symptoms of nutrient deficiencies or toxicities in any of the species tested. Foliar nutrient (N, I P, K, Ca, Mg, Mn, Zn, and Fe) concentrations in all species were within normal ranges, except for low Mn and Fe concentrations in red-osier dogwood during the second season.
Development of Field-grown Wildflower Sod
Authors: Johnson Anne Marie , Whitwell Ted
Published: February 2019

In a study examining the potential for production of a field grown wildflower sod, 29 annual and perennial wildflower species were evaluated. Species selection for the study was based on lack of a large taproot, adaptability to the southeastern climate, flowering period, and potential for surviving root undercutting. Species were individually seeded in 1-m2 plots in Fall 1993 and Spring 1994 to determine an optimum planting time. In early Spring 1994, fall seeded plots were undercut at a 5 cm depth with a hand held sod cutter. Spring planted species were undercut in early summer. After undercutting, sod pieces were placed on clear plastic under overhead irrigation for 7 weeks then transplanted to prepared field sites. Ratings for flower appearance, root mat density, top growth vigor and fresh root weights were taken at the time of undercutting and after transplanting. Fall-planted species had a higher survival rate than spring-planted species. Species with the highest ratings and greatest increase in fresh root weights from the time of undercutting to transplanting were yarrow (Achillea millefolium), oxeye daisy (Chrysanthemum leucanthemum), lance-leaf coreopsis (Coreopsis lanceolata), plains coreopsis (Coreopsis tinctoria), blanketflower (Gaillardia aristata), lemon mint (Monarda citriodora), blackeyed Susan (Rudbeckia hirta), and moss verbena (Verbena tenuisecta).
Evaluation of Fibrous-rooted Begonia Cultivars for the Landscape in West-central Florida
Authors: Howe T.K. , Waters W.E.
Published: February 2019

Fibrous-rooted begonia cultivars were evaluated for days to flower, flower size, flower color, leaf characteristics, plant dimensions and appearance during two seasons, Spring and Fall 1994. In spring, days from sowing to first flower among 62 cultivars ranged from 49 days for `Ambassador Coral', `Ambassador Soft Pink', `Prelude Coral' and `Varsity Rose' to 89 days for `Olympia Red'. Flower diameter ranged from 2.8 cm for `Gin' to 5.5 cm for `Lotto Pink'. At 126 days after sowing, plant height ranged from 16.5 cm for `Ambassador White' to 31.1 cm for `Encore Light Pink'. Subjective ratings showed cultivars were different with respect to floriferousness. In fall, days from sowing to first flower among 69 cultivars ranged from 76 days for `Atlanta White', `Atlanta Pink' and `Victory White' to 114 days for `Olympia Red'. Flower diameter ranged from 2.7 cm for `Roxy White' to 6.9 cm for `Lotto Pink'. Plant height at 118 days after sowing ranged from 5.1 cm for `Ambassador White' and `Lotto Scarlet' to 19.7 cm for `All Round Dark Rose/Dark Leaved'. Subjective ratings showed differences among the cultivars in appearance of foliage and floriferousness.
Recovery from “Near-lethal” Stress by Soaking Plant Tissue in Water
Authors: Shirazi A.M. , Fuchigami L.H.
Published: February 2019

Previously, we reported that plant recovery from “near-lethal” (NL) (sublethal) stresses depended on stage of development and poststress environment (PSE). Dormant red-osier dogwood (Cornus sericea) plants exposed to NL heat, freezing, and hydrogen cyanamide either died or were severely injured when stored at 0C or recovered at 23C and nautral condition. Exposure of dormant stem tissues of red oak (Quercus rubra), paper birch (Betula papyrifera) and European mountain ash (Sorbus aucuparia), to heat stress also resulted in higher ion leakage when they were stored at 0C PSE for 3 weeks. Soaking NL-heat-stressed (49C for 1 hour) stem tissue of red-osier dogwood in double distilled water for 48 hours before incubating at 0C PSE for 2 and 12 weeks resulted in lower ion leakage and 80% tissue survival. NL-stressed tissue had higher sodium and similar potassium leakage at 0C PSE. At 23C, PSE NL stress had no effect on leakage of these specific ion.
Cloning of Mannose 6-phosphate Reductase from Celery.
Authors: Everard John , Grumet Rebecca , Loescher Wayne
Published: February 2019

In celery, photosynthetic carbon partitioning between mannitol and sucrose is highly dependent on developmental (leaf age) and environmental (salt stress) factors. Mannose 6-phosphate reductase (M6PR) mediates a key step in mannitol biosynthesis and may regulate partitioning between sucrose and mannitol. We have constructed a cDNA library and have isolated M6PR-specific clones. Before library construction, poly(A)+ RNA, extracted from newly fully expanded leaves, was translated in vitro. A single polypeptide (35.1 kD), immunoprecipitated with M6PR-specific antisera, accounted for ≈5% of the total 35S incorporated into TCA-precipitated products. Parity between the molecular masses of the immunoprecipitated product and authentic M6PR indicated minimal posttranslational modification. The unidirectional primary library, constructed in UniZap XR vector (Stratagene), consisted of 1.53 million plaque forming-units (pfus) of which <0.4% were nonrecombinant, as estimated by “blue/white”' screening. After a single amplification, ≈0.14% of the 200,000 pfus screened with M6PR-specific antisera were identified as putative M6PR clones. Following two further rounds of screening and in vivo excision of the pBluescript phagemids their identity as full length M6PR clones was confirmed as follows: 1) IPTG-induced expression of M6PR activity in crude extracts; 2) IPTG-induced expression of a polypeptide that specifically interacted with M6PR antisera and with identical mobility (on SDS gels) to authentic M6PR; 3) 100% sequence homology to an internal peptide from a tryptic digest of purified M6PR. Based on these criteria, we conclude that we successfully cloned M6PR. The sequence is similar to several reductases from both plants and animals including an aldose 6-phosphate reductase from apple. Supported by USDA-NRI grant 940-1439.
Taxas Grapefruit Tree Size, Leaf Loss, and Yield Relationships: A Computer Training Program on Estimating Fruit Loss for Insurance Adjustors
Authors: Fucik John E.
Published: February 2019

To meet the Federal Crop Insurance's need to estimate the fruit crop on young citrus trees with no bearing history and partial fruit loss, the relationships between tree age, trunk and canopy size, and yields were studied. Pertinent data taken over many years from 1- to 7-year-old trees were analyzed using SAS regression procedures. The correlations for tree age × trunk diameter and truck diameter × canopy size were highly significant with R2 > 0.80. Although its R2 was only 0.20, the canopy size × yield correlation provided an acceptable estimate of the potential yields of grapefruit trees ≤6 years of age. The effect of 20% to 80% leaf loss on subsequent yields was determined in a field experiment, and the results included with a training guide on estimating leaf loss. The whole program was designed to provide a method by which insurance adjusters with little previous citrus experience could estimate postfreeze yield losses.
The Americans with Disabilities Act: A Case Study of a University Teaching Garden
Authors: Ploss Adrienne , Lerner B. Rosie , Dana Michael N.
Published: February 2019

The Americans with Disabilities Act (ADA) requires public entities to be readily accessible to individuals with disabilities, including public gardens. However, managers of such gardens are not likely to be familiar with the language of ADA or with what steps they must take to be in compliance. This study served to summarize the requirements of ADA as they pertain to a small public garden. In addition, the Purdue Univ. Horticulture Gardens (PUHG) were evaluated to determine the current level of compliance with ADA and to identify areas in need of attention. The result was an action plan, not only useful for PUHG, but one that can be adapted by other public gardens.
A Print-on-demand System for Producing Instructional and Extension Materials
Authors: McConnell James , Barber L. Robert
Published: February 2019

A Print-on-Demand (POD) System was developed to expand the availability of printed extension and educational materials. The layouts are developed on a computer using text files and digital images. Images can be edited with graphics programs before insertion into the layouts. The completed materials are stored, in final format, on disk and are printed on an as-needed basis or distributed over computer networks. The system greatly reduces the production time to a finished product and gives great flexibility in revising publications. The basic POD system consists of a computer, a mass storage device, and a printer. Photo CDs and video capture are the most common sources of digital images. Photo CDs produce higher-quality images but require more time to get the digitized images due to commercial processing. For Photo CDs, the images are photographed with a 35-mm camera and sent for processing and digitizing. With live video capture, a video camera is connected directly to a computer and images are digitized in real time. Tape recorded images also can be used, but the image quality is less than live video. Video images are digitized at 72 pixels per inch (ppi), and Photo CD images are available at >3000 ppi. Video images are best digitized at twice their desired size and reduced to final size when increasing the resolution.
Phenotypic Stability of Transgenic Citrus
Authors: Moore Gloria A.
Published: February 2019

We have produced a number of transgenic citrus plants via Agrobacterium-mediated transformation of seedling stem segments with a vector plasmid containing a β-glucuronidase (GUS) gene. All regenerated green shoots produced in our experiments are assayed histochemically for expression of GUS by cutting a section from the base of the shoot. Many of the shoots express GUS only in sectors, which vary in size from shoot to shoot. Analyses suggest that sectored regenerated shoots are chimeric, consisting of nontransformed cells as well as transformed cells. However, plants derived from shoots with large GUS+ sectors in the original assays do not necessarily contain the GUS gene; conversely, some plants derived from shoots with small sectors appear solidly transformed. Plants that appear solidly transformed have maintained gene expression for up to 5 years. None of the transgenic plants have obviously altered morphologies. It has not been possible to analyze progeny plants because of the long juvenile periods and polyembryony of the primary transformants. However, because citrus is clonally propagated, long-term phenotypic stability of primary transformants is the most important factor in producing useful transgenic plants.
WWWhat in the WWWorld is the WWWeb?
Authors: Ng Timothy J
Published: February 2019

The World Wide Web (WWW) provides users with a graphical computer interface to access digital information from Internet locations around the world. This information may be in the form of text, images, motion pictures, or sound. Web “pages” may also provide near-instantaneous links to other pages with related interests and information, and have the capability of allowing users to fill out forms on-line requesting additional information or services. WWW access is becoming increasingly available to individuals either through direct network links or by a modem connection through an Internet provider, the latter method generally requiring either SLIP or PPP service to establish a link. The background of WWW, its potential, and its future development will be discussed.
Plant Water Status as an Index of Irrigation Needs in Deciduous Fruit Trees
Authors: Shackel Kenneth A.
Published: February 2019

To be useful for indicating plant water needs, any measure of plant stress should be closely related to some of the known short- and medium-term plant stress responses, such as stomatal closure and reduced rates of expansive growth. Midday stem water potential (SWP) has proven to be a useful index of stress in a number of fruit trees. Day-to-day fluctuations in SWP under well-irrigated conditions is well-correlated to midday vapor pressure deficit, and hence can be used to predict a non-stressed baseline. Measurement of SWP helped to explain the results of a 3-year deficit irrigation study in mature prunes, which showed that deficit irrigation could have either positive or negative impacts on tree productivity, depending on soil conditions. Mild to moderate water stress was economically beneficial. In cherry, SWP was correlated to both leaf stomatal conductance and rates of shoot growth, with shoot growth essentially stopping once SWP dropped to between –1.5 to –1.7 MPa. In pear, increased fruit size, decreased fruit soluble solids, and increased green color were all associated with increases in SWP.