bluuebunny/crossref_metadata_2025 huggingface dataset:
Elevated Carbon Dioxide Storage of `Anjou' Pears Using Purge-controlled Atmosphere
Authors: Drake Stephen R.
Published: February 2019

`Anjou' pears (Pyrus communis L.) were placed in controlled-atmosphere (CA) storage immediately after harvest (<24 hours) or after a 10-day delay in refrigerated storage, and held there for 9 months at 1C. Oxygen in all atmospheres was 1.5% and CO2 was at either 1% or 3%. Atmospheres in the flow-through system were computer-controlled at ±0.1%. After removal from CA storage, pears were evaluated immediately and after ripening at 21C for 8 days. Pears stored in 3% CO2 were firmer, greener, and displayed less scald, internal breakdown, and stem-end decay than pears stored in 1% CO2. In addition, no internal discoloration of `Anjou' pears was evident when held with 3% CO2. `Anjou' pears held in 3%. CO2 retained the ability to ripen after long-term storage. A 10-day delay in atmosphere establishment had little or no influence on the long-term keeping quality or ripening ability of `Anjou' pears.
001 COLLABORATIVE LEARNING AND PARTICIPATORY ON-FARM RESEARCH: COVER CROPS AND VEGETABLE PRODUCTION SYSTEMS
Authors: Luna John M. , Green-McGrath Daniel , William Ray , Seiter Stefan , Tenas Tom
Published: February 2019

A participatory, on-farm research project was initiated in 1992 in an effort to enhance mutual learning, knowledge, and experience of integrating cover crops into western Oregon vegetable production systems. A major goal of the project was to include growers, agribusiness representatives, governmental agency, Extension and university researchers in a collaborative learning process, emphasizing grower participation in the design and implementation of on-farm research and demonstration projects. To facilitate this participation from the planning stage forward, four “focus sessions” were hosted by lead farmers in different areas of the Willamette Valley to define growers' needs and interests relating to on-farm research and demonstration trials.

Based on individual growers' specific experimental objectives, cover crop evaluation trials were established on ten farms. Typically on each farm, 5 to 10 cover crop species or mixtures (grain and legume) were planted in large plot strips. Twenty five different cover crop species, varieties, and mixtures were planted. Seasonal cover crop biomass and nitrogen accumulation rates were determined, with cover crop impacts on crop yields and economic returns evaluated at selected sites.
009 GENETIC VARIABILITY IN HIGHBUSH BLUEBERRY, VACCINIUM CORYMBOSUM L., FOR RESISTANCE TO THE BLIGHTING PHASE OF MUMMYBERRY, MONILINIA VACCINI-CORYMBOSII
Authors: Ehlenfeldt Mark K. , Brewster Vickie , Stretch Allan W.
Published: February 2019

Potted plants of 53 highbush and half-high blueberry cultivars were screened for resistance to the blighting phase of mummyberry, Monilinia vaccini-corymbosii under controlled nursery conditions over an 18 day infection period. Significant differences were observed in the susceptibility of different cultivars, with `Bluehaven', `Bluegold', and `Blueray' being among the most susceptible, and `Bluejay', `Jersey', and `Duke' being among the most resistant. Differences were also observed in the latent periods and rate of disease progress which may have a bearing on the severity of the secondary fruit infection phase. Preliminary observations suggest that shoot blighting and fruit infection frequencies are not strongly correlated under high inoculum conditions.
012 EXPLOITATION OF RUBUS STRIGOSUS IN RASPBERRY BREEDING
Authors: Daubeny Hugh A.
Published: February 2019

The indigenous North American red raspberry, Rubis strigosus has been neglected in breeding programs. Only four cultivars, `Cuthbert', `Latham', `Herbert' and `Ranere' provide most of the germplasm contained in present-day cultivars; no more than six individual wild genotypes of the species are represented by the four cultivars. In recent years, the B.C. breeding program has screened seedling populations of hitherto unexploited genotypes of the species from various locations in North America. Useful traits identified in selections from the populations include levels of resistance to 1) the North American aphid vector, Amphorophora agathonica, of the raspberry mosaic virus complex, 2) to several cane diseases and 3) to root rot caused by Phytophthora fragariae var rubi, as well as desirable fruit traits, such as bright, non-darkening red color and easy release. Selections with cultivar potential have now been identified in the second and third backcross generations from the species.
017 GROWTH REGULATOR EFFECTS ON HEIGHT CONTROL OF POTTED MUSSAENDA QUEEN SIRIKIT
Authors: Cramer Christopher S. , Bridgen Mark P.
Published: February 2019

Mussaenda, a tropical ornamental shrub developed in the Philippines is being examined as a potential greenhouse potted crop in the United States. Showy sepals of white, picotee, pink or red and fragrant, yellow flowers make Mussaenda an attractive patted plans however, the profuse upright growth habit of some Mussaenda cultivars is undesirable for pot plant culture. With this in mind experiments were conducted to determine the effects of three growth regulators at two concentrations each, as well as the application method and the number of applications on Mussaenda plant height.

Three growth regulators, daminozide (B-Nine), ancymidol (A-Rest), and paclobutrazol (Bonzi) were applied at two commercially recommended rates and two application methods (spray or drench). The treatment were daminozide at 2500 ppm and 5000 ppm (spray), ancymidol at 33 and 66 ppm (spray) and at 0.25 and 0.50 mg/pot (drench), and paclobutrazol at 25 and 50 ppm (spray) and at 0.125 and 0.25 mg/pot (drench). In subsequent experiments, the same growth regulators were applied with an increase in concentration and either two or three applications. The treatments were daminozide at 5000 ppm (spray), ancymidol at 66 and 132 ppm (spray) and at 0.50 and 1.0 mg/pot (drench), and paclobutrazol at 50 and 100 ppm (spray) and at 0.25 and 0.50 mg/pot (drench).

The most attractive potted plants were produced with two applications of daminozide at 5000 ppm or two applications of ancymidol at 0.5 mg/pot (drench). Higher concentrations or additional applications excessively reduced plant height. Three spray applications of 132 ppm ancymidol also produced an attractive potted plant. Paclobutrazol sprays or drenches at any concentration or application number were ineffective for reducing Mussaenda `Queen Sirikit' plant height.
041 OPTIMIZATION OF ULMUS SUSPENSION CULTURES FOR ELICITOR/PHYTOALEXIN EXPERIMENTS
Authors: Gingas V. M. , Kamalay J. C. , Domir S. C.
Published: February 2019

Suspension cultures of five elm selections (U. americana A, 680, 8630 and Del 2 and U. pumila S) exhibiting a range of susceptibility responses to the Dutch Elm Disease fungus (Ophiostoma ulmi) have been successfully established for future elicitor/phytoalexin studies. Calli initiated from foliar tissues of mature, greenhouse-grown trees cultured on a solid modified MS medium containing 2,4-D and BA were adapted to a liquid modified MS medium containing BA and either IAA or NAA. Cells were grown in either the presence or absence of light with continuous agitation. Uniform, rapidly dividing cell cultures were achieved when friable white or tan calli were grown in the medium containing 1 mg/l each NAA and BA in darkness. Cultures yielding an abundance of phenolic compounds exhibited decreased cell uniformity and proliferation. Increased phenolic production was associated with the presence of phenolics in the initial callus tissue, exposure to light and the use of IAA as the auxin source.
044 VARIETAL DIFFERENCES IN EARLY EX VITRO GROWTH AND DEVELOPMENT OF MICROPROPAGATED PONTEDERIA CORDATA L.
Authors: Stenberg Myrna , Kane Michael E. , Philman Nancy
Published: February 2019

Micropropagation is a commercially viable and ecologically sound method for producing native herbaceous wetland plants used for wetland revegetation projects. The ability to rapidly screen, select and store germplasm of wetland species genotypes with desirable characteristics of growth rate and habit, nutrient uptake capacity, and/or substrate preference would significantly impact how micropropagated wetland plants are marketed. Early screening of plantlet growth ex vitro may provide an efficient method to select for specific characteristics of growth rate and habit. Five micropropagated lines of Pontederia cordata of differing phenotype were established in vitro from Florida populations. Rooted microcuttings were established ex vitro in a shallow outdoor tank. Growth and development were monitored over a 9 week period. Significant differences in shoot growth and number, leaf area and number, flowering and dry weights were observed between the different Pontederia cordata varieties.
049 LONG-TERM GENETIC IMPROVEMENT OF CUT-FLOWER YIELD IN GERBERA
Authors: Huang Hongzhan , Harding James , Bvrne Thomas
Published: February 2019

The effects of long-term genetic improvement are measured by selection response predicted from estimates of narrow-sense heritability. However, changes of population mean must be partitioned into genetic and environmental components-in order to accurately estimate selection response.

A long-term selection experiment for cut-flower yield in the Davis population of gerbera (Gerbera hybrida, Compositae) was conducted for sixteen generations. Breeding value was estimated for individual plants in the population using Best Linear Unbiased Prediction (BLUP). Genetic change was calculated from breeding values of individual plants in each generation. The results of this study indicate: the long-term selection experiment was successful and necessary for genetic improvement. Genetic change over sixteen generations was 33 flowers. Mean breeding values increased monotonously with an “S” shape pattern. Environmental effects fluctuated from generation to generation. Cut-flower yield in the Davis population of gerbera will continuously respond to selection.
058 DATE OF NITROGEN APPLICATION AFFECTS UPTAKE BY FIELD-GROWN BLUEBERRIES
Authors: Throop Philip A. , Hanson Eric J.
Published: February 2019

Absorption of “N-enriched fertilizer by young `Bluecrop' bushes was compared following applications on six dates between April and Sept. Ammonium sulfate solutions containing 2.1 g N (10.2 atom % 15N) were dripped directly into the root zone of single bushes. Soil covers and irrigation were used to maintain similar soil moisture conditions during treatment periods. Bushes were excavated after two weeks of exposure, and separated into roots, stems, and current-season growth (shoots, leaves, fruit). Tissues were dried, weighed, and analyzed for 15N and 14N by mass spectrometry. Bushes treated in May, June and July absorbed a greater percentage of applied N (6-8%) than bushes treated in Apr, Aug or Sept (1-3%). Results indicate that fertilization between late May and late July may result in the greatest efficiency of fertilizer use.
069 EFFECTS OF APPLE BRANCH GIRDLING ON RETENTION AND QUALITY OF FRUIT AND VEGETATIVE GROWTH
Authors: Mitchell Carl E. , Barden John A.
Published: February 2019

In 1992, branches on `Triple Red Delicious'/M.7 were girdled. A factorial of treatments (control, 9mm girdle-uncovered, 9mm girdle-covered) and timings: 0, 15, 30, 60, & 90 days after full bloom(DAFB) was used. With `Golden Delicious'1M.7, branch treatments were: control, score, and 6mm, 9mm, & 12 mm covered girdles, each applied at 0, 15, 30, & 60 DAFB. In 1993, treatments were: control, 9mm uncovered girdle, & pruning saw cut; each was applied 0, 7, 14, and 21 DAFB. Each girdle was a complete ring of bark; scoring was a knife cut through the bark.

The 2 cultivars responded similarly to girdling. Effects were greatest to treatments at 0-30 DAFB, and included increased fruit set or retention, temporary suppression of vegetative growth, and increased levels of soluble solids in the fruit. Treatments affected starch levels in the fruit and flesh firmness, but these effects were inconsistent.
070 EVALUATION OF APPLE TREE TRAINING TECHNIQUES FOR HIGHER-DENSITY ORCHARD SYSTEMS IN NORTH CAROLINA
Authors: Parker Michael , Young Eric
Published: February 2019

Controlling vegetative growth resulting from a long growing season in the southeast is difficult while trying to promote early fruiting. This study was initiated in 1990 to evaluate higher density leader training techniques, cultivar interactions, and the benefits of pre-plant fumigation on apple replant sites. Another objective was to evaluate these management parameters in four regions with very different climates and elevations. The training techniques evaluated were, weak leader renewal, bending of the leader during the growing season, and partial terminal leaf removal every 10 inches of leader growth (without injuring the apical meristem). The cultivars used were Jonagored, Spur Gala, and Red Fuji, all on Mark rootstock. First and second year branching was not significantly different between the various training techniques. Yields during the third year did not appear to differ between the leader training techniques. Pre-plant fumigation appeared to be beneficial in increasing tree growth in only two of the four sites.
078 REDUCING AGRICULTURAL POLLUTION WITH RIPARIAN BUFFER SYSTEMS
Authors: Altier Lee S. , Lowrance R. Richard , Williams R.G.
Published: February 2019

Even with careful management, within-field practices are often insufficient to prevent considerable nonpoint source pollution to adjacent streams. Water resources suffer from sediment, N, and P transported in surface runoff and N in subsurface movement when fields are cultivated up to stream banks. The maintainance of forested buffer systems between farmland and streams has been proposed as a remedy for mitigating pollution. Chemical movement through such a buffer system has been monitored for several years at the University of Georgia Coastal Plain Experiment Station. With the aid of that data, the Riparian Ecosystem Management Model is being developed to simulate biological, chemical, and hydrologic processes in order to evaluate the effectiveness of buffer system management for reducing the influx of pollutants to streams. The model allows an examination of the long-term potential of a buffer system under changing environmental conditions.
086 SEVERITY OF LEAF SCORCH AND BLACK APHID DAMAGE TO PECAN AS RELATED TO WATER AVAILABILITY
Authors: Wood Bruce W. , Reilly Charles C. , Tedders W. Louis
Published: February 2019

Two years of observations on water availability, black aphids and leaf scorch provides evidence of substantial interaction among these factors. Foliage of irrigated trees of `Desirable', `Cheyenne', and `Wichita' cvs. exhibited much less leaf scorch, black aphid damage, free nitrogenous substances, and sugars than did nonirrigated trees.

Water stress appears to predispose foliage in such a way so as to greatly increase the ability of black aphids, and certain fungal pathogens to grow and/or reproduce on/in the affected foliage.

This appears to be associated with the organisms ability to induce biochemical changes that increase levels of free nitrogenous substances and sugars. The level and degree of chlorosis and area of foliar damage by black pecan aphids was much greater on nonirrigated trees.

Two years of observations on the relative resistance of about 50 cultivars resulted in genotype related differences in susceptibility to leaf scorch.
087 RELATIONSHIP BETWEEN SUMMER TEMPERATURE AND DEEP SUTURE FORMATION IN `BING' SWEET CHERRY
Authors: Southwick S. M. , Shackel K. , Yeager J. T.
Published: February 2019

`Bing' sweet cherry is the most widely planted cultivar grown in the Western US because of widespread market acceptance. High prices are associated with early maturing `Bings' so growers are inclined to plant in early maturing growing regions. High numbers of less marketable, abnormally shaped (deep sutures, spurs, doubles) fruit tend to be produced in these regions. It is thought that abnormal fruit development is associated with high summer temperatures. Dataloggers equipped with thermocouples were located in 7 California cherry growing regions. Thermocouples were positioned throughout tree canopies, monitoring flower bud temperatures for 2 seasons from May to October. A Richard's function was used to describe the relation of average daily temperature (July, August, September to the percentage of fruit with deep suture. Correlation coefficients (R2) of 0.85 and higher were found, with increases in average daily temperatures above 22C associated with the formation of abnormal fruit shapes. Heat lamps were used to increase spur temperatures 5-7C above ambient during the July through September period, High percentages of abnormal flowers were produced in the season after 2 July, but not after 21 August heating, Strategies to lower high summer canopy temperatures helped to reduce abnormal fruit shapes.
089 EFFECT OF ROOTSTOCK ON GROWTH, PRODUCTIVITY, AND FRUIT COMPOSITION OF ZINFANDEL GRAPEVINES
Authors: Striegler R.K. , Wineman D.R.
Published: February 2019

Selected rootstocks were evaluated for four seasons in a Zinfandel vineyard located in the northern San Joaquin Valley of California. The vineyard was drip-irrigated and vineyard spacing was 2.1m × 3.3m (vine × row). A two-wire vertical trellis system was used and row orientation was east to west. Vines were trained to a bilateral cordon and spur-pruned. Rootstocks included in the study were: AxR #1, Freedom, Harmony, Kober 5BB, and Teleki 5C. Vines grafted on AxR #1 rootstock were considered to be the control treatment.

A randomized complete block experimental design was used. There were six blocks and plots consisted of five vines. Data collected included yield, components of yield, fruit composition, bloom petiole nutrient content, shoot number, and pruning weight.

After the initial season, yields were consistently highest for vines grafted on Freedom rootstock, with yields only slightly lower on AxR #1 rootstock. Significantly lower yields were recorded for vines grafted on Kober 5BB and Teleki 5C. Rootstock did not have a consistent effect on fruit composition. Shoots/vine and shoots/meter of canopy were not significantly effected by rootstock. Dormant pruning weight was highest for Freedom and lowest for Kober 5BB.

These results suggest that rootstock selection can influence vineyard productivity in the northern San Joaquin Valley. Continued research is needed to determine long term effects of the rootstocks used in this study.
092 MEASUREMENT OF GRAPEVINE WATER USE WITH A WEIGHING LYSIMETER
Authors: Williams Larry E.
Published: February 2019

A weighing lysimeter (with a soil container 2 m wide, 4 m long and 2 m deep) was installed at the University of California's Kearney Ag Center in 1987. Diurnal, daily and seasonal vine water use has been measured yearly since then. Vine water use was 350, 400 and 580 mm the first, second and third years after planting. respectively. Vine water use (from budbreak to October 31) the subsequent four years averaged 815 mm per year. Reference crop ET (ETo) averaged 1172 mm (from budbreak to October 31) over the course of the study. Diurnal vine water use was highly correlated with the diurnal course of solar radiation. Maximum ET averaged 50 L vine-1 day-1 during the middle part of the growing season. Experimental vines surrounding the lysimeter were irrigated at various fractions (from 0 to 140% in increments of 20%) of vine water was measured with the weighing lysimeter. Maximum yields were obtained with the 80% irrigation treatment This study demonstrated the deleterious effects of both over and under irrigation on yield of grapevines.
096 QUANTIFYING THE EFFECT OF SUPPLEMENTAL LIGHTING ON PLANT TEMPERATURES IN GREENHOUSES
Authors: Faust James E. , Heins Royal D.
Published: February 2019

The effects of supplemental lighting on vinca (Catharanthus roseus L.) plant temperature were quantified in greenhouses maintained at air temperatures of 15. 25, and 35C. High-pressure sodium (HPS) lamps delivering 100 μmol·m-2·s-1 PPF provided 73 W · m-2 of total radiation (400 to 50,000 nm) to lighted plants. Plant shoot-tip temperature was measured by using 40-gauge thermocouples. Relative to air temperature, plant shoot-tip temperature depended on the irradiance and vapor-pressure deficit (VPD). Irrespective of VPD, the additional irradiance absorbed by plants under the HPS lamps increased plant temperature 1 to 2°C. Under relatively low VPD conditions (1 kPa), plant temperature was greater than air temperature, while under high VPD conditions (4 to 5 kPa), temperature of both lighted and unlighted plants remained below air temperature throughout the day. Temperature of lighted plants however, remained 1 to 2°C above that of unlighted plants. Analysis of a degree-day model of vinca development showed hastened development associated with supplemental lighting could be explained by increased plant temperature rather than any specific photosynthetic effect.
100 ROLE OF LIGHT INTENSITY IN THE DEVELOPMENT OF OSTRICH FERN
Authors: Donelan Matthew , Corey Kenneth
Published: February 2019

Crowns of ostrich fern (Matteuccia struthiopteris L. Todaro) were field-planted in June 1993 on a Hadley silt loam in South Deerfield, Mass. Shade cloth was used to alter light intensity to determine if light intensity effects growth and development of fronds and crowns. Light levels were 22% (low), 45% (intermediate), 72% (high), and 100% (full) of ambient conditions. Survival of crowns decreased with increasing light intensity with only 22% survival under full light. Low, intermediate, and high light levels resulted in 89%, 75%, and 56%, respectively, of crowns producing shoots. Light intensity did not effect the number or length of fronds produced. Frond length reached a maximum after 2 months growth. Development of secondary crowns was enhanced at intermediate and high light intensities. Final crown weight was significantly correlated with initial crown weight regardless of light intensity. Crowns will be vernalized and forced hydroponically to determine effects of light intensity and crown size on growth of croziers.
102 EFFECT OF BACKFILL AND PLANTING BED AMENDMENTS ON GROWTH AND DROUGHT TOLERANCE OF ACER RUBRUM
Authors: Smalley Timothy J. , Wood Carleton B.
Published: February 2019

Commonly used planting techniques and soil amendments were compared to determine their effect on root growth, shoot growth, and drought tolerance of 2.5 cm caliper Acer rubrum. Study I: Trees were planted on 6 April 1992 into holes backfilled with 1) native soil, 2) 50% aged pine bark: 50% native soil, 3) 50% Mr. Natural™:50% native soil, or 4) 100% Mr. Natural™. Mr. Natural™ consists of granite sand, expanded shale, and composted poultry litter. After two years, no differences in growth or survival existed. Study II: On 8 April 1992, trees were planted in 1) unamended planting holes, 2) tilled planting beds, or 3) tilled and pine bark-amended planting beds. Five months after planting, the root growth in the tilled and tilled-amended beds did not differ, but both had more root growth than planting holes. Amendment-induced nitrogen deficiency reduced shoot growth of the tilled-amended treatment during the first year. After two years, the planting hole treatment exhibited the least shoot growth, while shoot growth of tilled and tilled-amended treatments did not differ. StudyIII: Selected trees in study II were drought stressed for 8 weeks beginning 4 August 1993. No differences in relative leaf water content among treatments were observed Results suggest that native soil should be used as backfill in planting holes; however, tilling a planting bed increases root and shoot growth compared to planting in a hole. Amending beds with pine bark did not increase growth or drought tolerance.
104 HORTICULTURAL USES FOR SEWAGE SLUDGE COMPOST
Authors: Bevacqua Robert F. , Mellano Valerie J.
Published: February 2019

Compost made from sewage sludge (40% by volume) and chipped trimmings of Eucalyptus trees (60%) was evaluated as a soil amendment for the field. production of onion (Allium cepa cv. Spanish Sweet Utah), lettuce (Lactuca sativa cv. Black Seeded Simpson), snapdragon (Antirrhinum majus cv. Sonnet Yellow), and turfgrass (Festuca arundinacea cv. Marathon). Turf shows a strong reponse to preplant compost applications and is relatively tolerant of the buildup of soluble salts that can occur with compost applications. Also since it is not a food crop the possible uptake of heavy metals is not a major concern. These results indicate the amending of soil for the planting of turf is a likely commercial use of the compost. The authors are presently evaluating the use of the compost as a top dressing on turf plantings.
111 EFFECTS OF N SOURCE, APPLICATION FREQUENCY, AND SOIL NITRATE CONCENTRATION ON PEPPER YIELD AND QUALITY
Authors: Batal K.M.
Published: February 2019

Various applications of N fertilizer formulations to bell pepper plots were made to affect soil nitrate-N concentrations from 5 to 30 ppm throughout the growing season. Number and weight of marketable grades for the 1st and 3rd harvests were improved by increasing soil N from 5 to 30 ppm. In the final (4th) harvest, marketable yield was highest for applications maintaining soil N of 25 ppm. Earliness was enhanced by N sources with Ca(NO3)2 producing the earliest yield followed by NaNO3 and NH4NO3. Total marketable yield produced by Ca(NO3)2 or NaKNO3 was 3 t/ha higher than by NH4NO3 applications. High marketable quality was maintained with Ca(NO3)2 and NaNO3 treatments. The highest blossom-end rot (BER) incidence was associated with NH4NO3 applications. But the N source effect on BER was strongly influenced by soil nitrate levels. At 10-20 ppm soil N, leaf Ca decreased during the 8 to 12 week period, but at higher soil N, leaf Ca remained unchanged, indicating a constant Ca uptake during the critical growth period.
112 PRESIDEDRESS SOIL NITRATE TEST FOR SWEET CORN
Authors: Heckman J. R. , Prostak D. J. , Hlubik W. T.
Published: February 2019

The presidedress soil nitrate test (PSNT) is an in-season soil test that evaluates the N supplying capacity of soil before side dressing to adjust N application rates. Increasing acceptance of this soil test among field corn growers in New Jersey has shown it to be an effective practice. Nitrogen application rates were reduced by an average of 45 kg-1 ha without loss of crop yield. Field calibration research to extend use of the PSNT to sweet corn has the potential to improve N fertilizer recommendations for this crop. A critical concentration of 25 mg kg-1 NO3-N in the surface 30 cm of soil is generally considered adequate for field corn. Certain crop features of sweet corn (earlier harvest, smaller plant size and population) suggested that the critical NO2-N level might be lower than for field corn while market quality suggested that it might be a higher value. Results from 40 sweet corn field calibration sites in New Jersey indicate that the PSNT critical soil NO3-N concentration may be greater for sweet corn than field corn. A preliminary critical level of 30 mg kg-1 NO3-N in the surface 30 cm of soil is suggested for use of the PSNT on sweet corn. Further research is being conducted to improve sidedress N recommendations based on the PSNT.
116 ANATOMICAL CHARACTERIZATION OF PHOTOSYNTHETIC CAPACITY OF EIGHT Fragaria chiloensis GENOTYPES
Authors: Foote Paul W. , Cameron J. Scott , Klauer Stephen F.
Published: February 2019

Leaf-area based CO2 assimilation rate (ALA as an Indicator of genotypic differences in photosynthetic capacity is questioned on the basis of correlations found between ALA and specific leaf weight and small leaf size. To address this question of photosynthetic apparatus concentration In F. chiloensis genotypes differing significantly in ALA, visual image analysis software was used to quantify a number of leaf anatomy parameters. In 1991 and 1992, after gas exchange measurements in the field, leaf tissue was prepared In cross-sections and leaf clearings for light microscopy. Cross-sections were used to measure internal anatomical parameters and clearings for vein and stomatal densities.

Analysis of variance of 1991\92 measurements showed significant genotypic variation for leaf veination, leaf thickness, palisade cell length, cross-sectional area In mesophyll tissue and internal air space. Differences in stomatal density were observed in 1991. None of the anatomical parameters measured were correlated with ALA. This suggests that the concentration of physical apparatus Is not the major source of variation In ALA among these eight genotypes.
117 AN ANALYSIS OF STOMATAL v. NON-STOMATAL LIMITATIONS TO PHOTOSYNTHESIS IN RED RASPBERRY
Authors: Fernandez Gina E. , Pritts Marvin P.
Published: February 2019

Stomatal and non-stomatal limitations to photosynthesis were determined for both primocanes and floricanes of “Titan” red raspberry. Limitations to photosynthesis were determined from the relationships between rates of photosynthesis (A), stomatal conductance (g), and the internal CO, concentration (Ci) of the leaf. We generated this data (A, g and Ci) using steady state gas exchange. Calculation of limitations were determined from A/Ci and A/g curves, second order polynomial regression and computer simulation. Using methods developed by Farquhar & Sharkey (1982), stomatal limitation during and after fruiting in both primocane and floricane leaves was approximately 28%. Non-stomatal limitations were determined through computer modeling and expressed as the maximum rates of carboxylation, Vcmax, and of electron transpont, Jmax.
120 RESPIRATORY CHANGES IN APPLE VEGETATIVE BUDS AND INTERNODES DURING BUDBREAK
Authors: Dautlick Tania K. , Young Eric
Published: February 2019

One-year-old potted `Jonagold' apple trees on M. 9 EMLA rootstock were chilled in a cold room at 5C for 1320, 3288 or 4464 hours. They were then placed in a 22C greenhouse for forcing. Rate of dark respiration of buds and internodes was measured in vivo using the LICOR LI 6200 portable photosynthesis system. Measurements were taken on each tree at several distances from the shoot apex during the forcing period. The new apical growth was removed from half of the trees when apical growth was 2-4cm. Removal of apical growth did not appear to influence respiration. Respiration of both buds and internodes generally decreased with distance from apex. As budbreak occurred or when trees received excess chilling hours, the effect of distance from apex on respiration decreased. Excess chilling also resulted in greater and more rapid budbreak.
131 PEROXIDATIVE CHALLENGE OF PLASMA MEMBRANE VESICLES FROM BELL PEPPER FRUIT LEADS TO DECREASED H+ATPase ACTIVITY
Authors: Cowart Darlene M. , Shewfelt Robert L.
Published: February 2019

-Lipid peroxidation has been proposed as an important factor in chilling injury of susceptible fruits and vegetables. The effect of in vitro peroxidative challenge on H+ATPase activity in intact plasma membrane vesicles and solubilized enzyme was determined by incubation with (1) deionized water (control), (2) Fe3+-ascorbate, and (3) lipoxygenase (LOX) + phospholipase A2(PLA2) for 0, 30, and 60 min. Enzyme activity increased throughout the incubation period with no accumulation of thiobarbituric acid-reactive substances (TBA-RS) in the control, but vesicles challenged by the peroxidative systems showed significant increases in TBA-RS and decreases in membrane-bound H+ATPase activity. Greater losses in H+ATPase activity were observed in solubilized enzyme than in intact vesicles. The results indicate that loss of H+ATPase activity due to chemical modification of the protein rather than changes in membrane fluidity and suggest that modification is away from the active site.
135 LOW TEMPERATURES AND CONTROLLED ATMOSPHERES MAINTAIN QUALITY OF FRESH CUT BELL PEPPER
Authors: El-Bassuoni Rawia , Cantwell Marita
Published: February 2019

Bell pepper fruits (green and red) were stored intact or prepared in dices (1 × 1 cm), washed with chlorinated water, biot dried, and stored in air or controlled atmospheres (air or 3% O2 with 0, 5 or 10% CO2) at 0, 5 or 10C for up to 20 days. Dicing resulted in respiration rates 2-3 times higher than those of intact peppers, but did not result in measureable increases in ethylene production. Samples were periodically transferred to 15C for 12 h before evaluation for visual quality, decay, discoloration, aroma, flavor, texture, and sugar content. Quality changes were similar for green and red fruit of the same cultivar. Intact peppers are chilling sensitive, but the quality of diced peppers was maintained best at 0C. The shelf-life of diced pepper at 10 and 5C was 1/2 to 2/3 that of intact peppers. Atmospheres containing 5 or 10% CO2 reduced decay and increased the shelf-life of diced peppers, but were not as effective as storage in air at 0C. Storage at 0C also resulted in greater retention of sugars than storage under other conditions. High CO2 atmospheres resulted in softening of pepper tissue and increased electrolyte leakage. Aroma and flavor scores declined more rapidly in CA than in air storage.
136 DIFFERENTIAL SCANNING CALORIMETRY (DSC) OF AVOCADO AND MANGO FRUITS STORED IN AN INSECTICIDAL ATMOSPHERE
Authors: Yahia Elbadi M. , Dominguez Marisela Rivera
Published: February 2019

Modified and controlled atmospheres with ≤ 0.5% O2 and/or ≥ 50% CO2 are insecticidal. In previous studies we have found that avocado is very sensitive and mango is very tolerant to these atmospheres. We used DSC to study the differences in response between these two fruits, and to relate that with their sensitivity/tolerance to hypoxia. Fresh or lyophilized tissues of fruits stored in air or in an insecticidal atmosphere were scanned at a temperature range of 10 to 145°C at a rate of 10°C/min. There were qualitative and quantitative differences between thermograms. There were fewer endotherms in thermograms of fresh tissue samples than in lyophilized tissue samples. Avocado thermograms showed a major endotherm at ca 15°C and 2 minor endotherms at ca 105-110°C. In addition, mango heating thermograms showed another major endotherm at ca 80°C. This endotherm was not present in the heating thermograms of avocado. and might represent a contributing factor in the tolerance of mango to insecticidal atmospheres.
156 INFLUENCE OF MUNICIPAL SOLID WASTE (MSW) COMPOST ON GROWTH, YIELD, AND HEAVY METAL CONTENT OF TOMATO
Authors: Ozores-Hampton M. , Schaffer B. , Bryan H. H.
Published: February 2019

The effects of amending soil with municipal soil waste (MSW) on growth, yield and heavy metal content of tomato were tested with different irrigation rates. The following MSW materials were incorporated into oolitic limestone soil: 1) Agrisoil compost (composted trash), 2) Daorganite compost (sewage sludge), 3) Eweson (composted trash and sewage sludge), and 4) no MSW (control). Two rates (high and low) were applied to the soil for each compost. There were no significant effects of irrigation rate on any of the variables tested for tomato in 1991 or 1992. Therefore, the lowest irrigation rate appeared to be adequate for optimum tomato production. Plants grown in Daorganite at the lowest rate of 8 t/ha had greater growth and yield than plants grown in the other MSW materials or the control. Agrisoil and Eweson composts did not increase growth or yield, which may have been due to suboptimal application rates of these materials. There were no differences in the concentration of heavy metals in fruit or leaves among MSW materials or rates. MSW rate generally had no effect on root heavy metal concentration, except for Eweson where the high rate resulted in a higher root zinc concentration than the low rate. There were signifant differences in root concentrations of lead, zinc, and copper among MSW materials. Leaf concentrations of all heavy metals tested were within normal ranges for tomato.
161 CALCINED CLAY AND ALUMINA AMENDMENTS INCREASE PO4 AND K RETENTION OF SOILLESS CONTAINER SUBSTRATES
Authors: Williams Kimberly A. , Nelson Paul V.
Published: February 2019

Soilless substrates have little capacity to sorb PO4. One way to reduce PO4 leaching during production is to increase the substrate retention of PO4. Adsorption isotherms were created at 25 C for alumina (aluminum oxide); the 2:1 calcined clays arcillite (montmorillonite plus illite) and attapulgite.; and a medium of 70 peat: 30 perlite using solutions of KH2PO4 at rates of P ranging from 0 to 20000 μg·ml-1. Material sorbed at the rate resulting in maximum P adsorption was then desorbed 22 times. Sorbing concentrations necessary to establish an equilibrium P concentration of 10 μg·ml-1 in the substrate solution were estimated from these curves. Materials were-charged with P at these estimated rates and evaluated in a greenhouse study in which each material was tested at 10 and 30% by volume of a 70 peat: 30 perlite substrate used to produce Dendranthema × grandiflorum `Sunny Mandalay'. Phosphate, K, and pH were determined on unaltered soil solutions biweekly throughout the cropping cycle and foliar analyses were determined on tissue collected at mid- and end-crop. Isotherm and greenhouse data indicated that alumina, arcillite, and attapulgite effectively retained and slowly released K as well as PO4 over time. Alumina was most effective at retaining P, sorbing 16800 μg/cc compared to 3100 and 7800 μg P sorbed/cc for arcillite and attapulgite, respectively, when sorbed at P concentrations resulting in an equilibrium concentration of approximately 10 μg P/ml.
177 TRANSGENIC PEACH PLANTS CONTAINING A CYTOKININ BIOSYNTHESIS GENE DISPLAY ALTERED GROWTH IN VITRO AND UNDER GREENHOUSE CONDITIONS
Authors: Hammerschlag F. A. , Smigocki A. C.
Published: February 2019

Transgenic plants containing introduced phytohorm one genes have been shown to display altered growth and morphogenetic potential. Peach plants transformed with the ipt gene from Agrobacterium tumefaciens strain tms 328::T n5 and containing elevated levels of cytokinins were screened in vitro for compact growth habit on four different levels of 6-benzyladenine (BA). After nine weeks in vitro, the average number of axillary shoots per plant foe two of the transformants, 99-1 and 40-1, ranged from 1.5 to 6.6 times that for the controls on 0-30 uM of BA, whereas average fresh weight ranged from 1.1 to 3.6 times that for the controls. One of the transformants, 94-1, produced a greater number of axillary shoots only on 30 μM BA. Rooted plants derived through micropropagation from the original transformants were monitored for 30 months under greenhouse conditions. The average height of transformants 94-1 and 99-1 after six months in the greenhouee was 88 and 77% of controls, respectively and after 30 months was 90 and 75% of controls, respectively. In comparison to controls, transformants exhibited a greater number of branches per meter per plant after six weeks, but a lesser number after 30 months. These results suggest that the introduction of a cytokinin gene may be a useful approach to obtaining peach trees with a compact growth habit.
187 HYDROGEN CYANAMIDE BLOOM THINNING OF PEACHES AND APPLES
Authors: Worthington J. W. , Lyons Calvin G. , Lipe John A.
Published: February 2019

This research was set up to determine the effectiveness of hydrogen cyanamide as a bloom thinner on peaches and apples. When applied at full bloom hydrogen cyanamide at 0.5 to 1% was effective at reducing fruit set on several varieties of peaches and apples in two different years. Yields were not effected when the lower rates were used. These results indicate that hydrogen cyanamide holds potential as a bloom thinner for both stone fruit and apples when used at the proper rates and timing.
194 COLD HARDINESS AND CARBOHYDRATE CONTENT OF FOUR CULTIVARS OF FIELD-GROWN SOUTHERN MAGNOLIA
Authors: Haynes C. L. , Lindstrom O. M. , Dirr M. A. , Severson R.
Published: February 2019

Cold hardiness and carbohydrate content of 4 cultivars of field-grown southern magnolia (Magnolia grandiflora L.) were determined monthly during the 1992-1993 winter. Initially, `Claudia Wannamaker', `Little Gem', `Timeless Beauty', and `Victoria' had similar stem and leaf cold hardiness estimates of -6C in October. However, by February `Claudia Wannamaker' and `Victoria' stems were 6 and 3C more cold hardy than `Little Gem' and `Timeless Beauty' stems. `Claudia Wannamaker' leaves were also 6C more cold hardy than `Little Gem' and `Timeless Beauty' leaves in February. Carbohydrate analysis indicates increases in oligosaccharides during cold acclimation in fall.
196 EFFECTS OF DROUGHT AND ROOT-ZONE TEMPERATURE ON GROWTH AND WATER RELATIONS OF SILVER MAPLES FROM FIVE PROVENANCES
Authors: Aiello Anthony S. , Graves William R. , Preece John E.
Published: February 2019

Along with its horticultural uses, silver maple (Acer saccharinum L.) can be grown for biomass in areas that vary greatly in annual rainfall and temperature. Silver maples from five provenances ranging from 33 to 46° N latitude were subjected to drought stress and to high root-zone temperature (RZT) in separate experiments to assess their suitability as biomass sources. In the drought experiment, control plants were irrigated every 2 days, while stressed plants were irrigated every 15 days. Initial results indicated provenance differences among control plants in dry mass, leaf area, and transpiration. Drought reduced growth and mitigated differences among provenances. Osmotic potential of leaves was higher in control plants than in drought-stressed plants. Plants from two provenances (33 and 44° N) were grown with RZT of 24 and 34 C for 3 weeks. Gain in fresh mass over time was reduced at 34 C for plants of both origins, but plant dry matter and leaf surface area were similar at the two RZT. Data collected to date suggest resistance to drought and high RZT is similar in plants of different provenances.
199 A PERFORMANCE. EVALUATION ON TWELVE SPECIES OF ORNAMENTAL GRASSES UNDER WATER STRESS IN GREENHOUSE AND FIELD CONDITIONS
Authors: Wolfe June , Zajicek J.M. , Hussey M.A.
Published: February 2019

Six native Texas and six introduced ornamental grass species were chosen for an evaluation of water use performance and aesthetic value under drought stress to identify material most appropriate for water conserving landscapes. Greenhouse and field experiments determined the overall performance of the grasses under drought conditions. A public survey evaluated the aesthetic value of investigated species. Greenhouse work determined that examination of total chlorophyll content was not a useful parameter for predicting drought stress. Water use and visual aesthetic decline rates were determined for all species in the greenhouse. On average, native and introduced species performed equally well. Imperata cylindrica exhibited the lowest rates of water use (by 92%) and visual decline (by 51%) in the greenhouse and was the most conservative water user in the field with lowest stomatal conductance (by 76%). The survey found that grasses were acceptable as ornamentals in the landscape and natives and introduced species equal in preference.
206 HORTICULTURAL SCIENCE AND FORENSIC SCIENCE: THE POTENTIAL CONTRIBUTION OF HORTICULTURAL SCIENTISTS AT CRIME SCENES
Authors: Cameron J. Scott
Published: February 2019

The criminal justice system is served by many experts who provide special assistance to law enforcement professionals during criminal investigations. One of these specialized areas. forensic botany, has traditionally been an activity of the systematic botanist who identifies plant material associated with a suspect or crime scene. From this Information, suspects can be placed at crime scenes and information such as time of death or movement of victims can be determined. Few plant scientists are involved In this emerging field which has the potential to make contributions similar to those made today by forensic anthropology.

Plant scientists with training In systematic botany, plant anatomy, plant growth and development, and statistics and probability can make significant contributions to criminal investigations. The use of plant identification and plant growth analyses In recent criminal Investigations will be described. The role of horticulture in the future of forensic science and the development of new techniques In forensic plant science will also be discussed.
211 AN EXPERT SYSTEM FOR URBAN TREE SELECTION
Authors: Gilman Edward F.
Published: February 2019

This computer program, delivered-on a CD-ROM disc, develops a list of tree species and cultivars suited for a specific planting site. It requires little previous computer experience or tree knowledge to operate. Using multiple choice questions, the program automatically brings the user through above ground and below ground site analysis. This includes all the considerations known to influence proper species section for a planting site. Using C++ programming and the NASA-developed expert system shell called CUPS, a list of facts is generated as the user answers the questions. At the press of a button, the program finds trees that match the attributes the expert system placed on the facts list. The list can be further modified by choosing among ornamental and other tree attributes that might be of interest to the user. The tree list can be printed in several seconds. A typical run through the expert system takes 2 to 4 minutes to answer about 20 to 25 questions. The program contains data on 681 trees, more than 1,800 color photographs, and a 4-page fact sheet including 3 line drawings for each tree totaling more than 2,000 pages. The program can also be used as a reference by paging through the tree records to find information about specific trees. Each tree record lists on the computer monitor a large variety of data for the tree, allows you to view text about the tree, displays a line drawing of the entire tree, and displays up to seven photographs of each tree. The program will be distributed nationwide as a tool to help landscape architects, horticulturists and others select the right tree for the right place.
217 OPTIMIZING N AND P FOR ROCKWOOL-GROWN CUCUMBERS
Authors: Schon M. K. , Compton M. P.
Published: February 2019

Experiments were conducted to determine the optimum levels of N and P for use in greenhouse cucumber (Cucumis sativus L. `Vetomil') production. Plants were grown in rockwool slabs using a double-stem pruning method. Treatment 1 plants were fed 90 ppm N until N in the growing slabs was depleted (averaged <10 ppm); N was then increased to 175 ppm. Treatment 2 and 3 plants were given a constant 175 or 225 ppm N, respectively. Plants in all treatments depleted N in the slabs by three to four weeks after transplant (WAT); N remained low in Treatment 1, but recovered to adequate levels in Treatments 2 and 3. Phosphorus was provided at a constant 50 ppm and was depleted to <10 ppm in the slabs of all three treatments by four WAT. Fruit yield increased significantly with each increase in solution N. Similar results in a second trial indicated that N and/or P may have been limiting factors even at the highest levels tested. Research will continue to determine optimum levels of N and P for maximizing yield.
218 EFFECT OF NITROGEN FERTILIZERS ON THE GROWTH AND VOLATILE OIL CONTENT OF TAGETES MINUTA L. PLANTS
Authors: Abdalla Nadia M. , Al-Badawy Ahmed A. , Ali Mohamed K. , Al-Azeem Mervat A. Abd
Published: February 2019

Mexican marigold (Tagetes minuta, L.) plants were fertilized with urea, nitrokima and ammonium nitrate at the rates of 0, 25, 50 and 100 kg N/feddan (feddan = 4200 sqm). These fertilizers were added at three batches during the growing season.

The application of nitrogen fertilizers enhanced plant growth in terms of plant height, stem diameter, branch number and the dry weights of leaves, flowers and herb. Also, these fertilizers increased the volatile oil content in the leaves and flowers. The most effective fertilizer was ammonium nitrate especially when the highest rate was applied as it gave 3.87 g/plant compared to 2.28 g/plant for the control plants.

The contents of photosynthetic pigments, reducing and total soluble sugars were increased compared to the control plants.