bluuebunny/crossref_metadata_2025 huggingface dataset:
182 Growth of First-year Grapevines in Desiccated Rye Residues With and Without Follow-up Weed Control
Authors: Bordelon Bruce P. , Hubertz Jill
Published: February 2019

In a previous study to determine the feasibility of using herbicide desiccated cover crops for weed suppression during vineyard establishment, we found that weed suppression is excellent for about 6 to 8 weeks after desiccation in fall-planted rye. By the end of the season, however, weed growth in rye plots was similar to weedy control plots. Vine growth was reduced in rye plots compared to weed-free bare ground plots. Because of the experimental design, no follow-up weed control was performed in the rye plots and weeds eventually became well-established. So, it was impossible to determine if reduced vine growth was due to weed competition or allelopathy from the rye residues. A second study was conducted to determine the effects of follow-up weed control (with glyphosate) in fall-planted rye plots and weedfree bare ground plots. Results indicate that vine shoot number, shoot length, leaf area, and top growth dry weight was greatest in weedfree bare ground, less, but not significantly so in rye with follow-up weed control, and significantly less in rye without follow-up weed control. Root dry weight was reduced in rye with and without follow-up weed control compared to weedfree bare ground. Root dry weight was reduced 37% in rye with follow-up weed control and 63% in rye without follow-up weed control compared to weedfree bare ground. These results suggest that weed competition is not the primary cause of vine growth reduction in herbicide desiccated rye cover crops, so there is likely allelopathic effects of the rye residues on grapevines, which would limit using rye as a desiccated cover crop during vineyard establishment. However, there may be some value in using rye in established vineyards to reduce vigor.
187 Effect of Nutrient Source on Quality and Yield of Strawberry Grown in Verticillium-infested Soil
Authors: Mitchell V. , Brooks C. , Morant M.
Published: February 2019

Verticillium albo-atrum, a cosmopolitan pathogen that causes wilt of strawberry, can cause economic losses for growers and increased prices for consumers. This study was conducted in 1998 to assess the impact of organically and inorganically supplied N on fruit yield and quality. `Allstar' (resistant) and `Raritan' (susceptible) varieties of strawberry were planted in V. albo-atrum-infested soil that was amended with poultry compost (organic N) or ammonium nitrate (inorganic N). Fruit quality was assessed as titratable acidity (TA), soluble solids content (SSC) using a refractometer, and reducing sugars concentration using a gas chromatography. Disease incidence was below threshold level and did not affect the results of this study. Plants grown in compost amended plots produced an average of 41 fruit, weighing 354 g, compared to the 34.5 fruit weighing 487 g that were harvested from the inorganically amended plots. TA was not affected by the treatments. Overall, yield of `Raritan' was 40% greater than that of `Allstar'. The SSC of `Allstar' was highest in fruit that were produced in compost-amended soil in contrast to that of `Raritan', which was greatest for plants that were grown in the inorganically amended plots. Fruit grown in the inorganically amended plots generally had a higher concentration of glucose and fructose, but sucrose was found only in fruit from the control plots. Poultry compost may be an alternative source of N for producing strawberries but this needs to be further evaluated because of the slower release of nutrients over time.
211 Growth, Photosynthesis, Biomass Partitioning, Yield, and Their Relationships in Processing Snap Beans
Authors: Hao Xiuming
Published: February 2019

In Summer 1998, 17 standard cutting and 14 small-sieve wholepack varieties and advanced lines of processing snap beans were evaluated at the Greenhouse and Processing Crops Research Centre in Harrow, Ont. The varieties and advanced lines were arranged in randomized complete blocks with four replications. Of the standard cutting varieties and advanced lines, `Saratoga' was the earliest variety, which was harvested 5 to 10 days earlier than rest of the cultivars. `EX 371' had the highest yield, pod dry matter, and biomass and the second highest pod dry matter content, leaf area, and harvest index (total pod dry matter/biomass). `Saratoga' had similar yield as `EX 371', but its total pod dry matter production was much lower than `EX 371' due to its lowest pod dry matter content. Of the small-sieve wholepack varieties and advanced lines, `Marseilles' had the highest yield, pod dry matter, pod dry matter content, biomass, and harvest index and second largest leaf area. Leaf photosynthesis (measured at 1500 μmol•m-2•s-1 photosynthetic photon flux density, 65% relative humidity, 28 °C, and ambient CO2 with LI-6400 portable photosynthesis system in full bloom stage) ranged from 21.3 (EX 351) to 28.3 (Carlo) μmol•m-2•s-1. In both standard cutting and small sieve wholepack varieties and advanced lines, yield was significantly and positively related to total biomass, biomass allocation to pods and leaf area, and so was the total pod dry matter. Bean pod yield was significantly and negatively correlated with pod dry matter content in standard cutting varieties and advanced lines. Bean pod yield did not have significant relationships with leaf photosynthesis and chlorophyll. Therefore, the yield of processing snap beans might be mainly determined by total leaf area and biomass allocation to pods.
215 Effect of Overhead Misting on Leaf Surface Microclimate of Greenhouse Cucumber
Authors: Zhang Y. , Shipp J.L. , Jewett T.J.
Published: February 2019

Overhead fogging or misting is an essential technique applied in modern greenhouses for cooling and humidifying. This technique can be used to promote yield and quality of greenhouse crops either by providing favorable environment for the plant growth or by increasing the efficiency of greenhouse pest and disease control. In this study, the effect of high-pressure overhead misting on greenhouse climate and leaf surface microclimate conditions for cucumber crops in a glass greenhouse was investigated. It was found that the temperature of the greenhouse air was lowered by 5-6 °C and relative humidity was increased by 20% to 30% during misting. The temperature of sunlit leaves was slightly reduced in the morning (2-3 °C), and leaf wetness duration was significantly extended by misting. Leaf wetness duration under misting was predominately influenced by light intensity at the leaf level and was modelled as a function of misting period and average radiation intensity. Results of this study can be used to improve the predictions of pest and disease breakout and the efficiency of their control measures. The empirical model developed in this study can be integrated with leaf surface microclimate models to correctly predict surface moisture conditions and evaporative cooling from water films at the leaf surface.
221 Gibberellic Acid Application Timing Effects on Juice Yield and Peel Quality of `Hamlin' Oranges
Authors: Davies F.S. , Fidelibusa M.W. , Campbell C.A.
Published: February 2019

Gibberellic acid (GA) applied in late summer or fall delays subsequent loss of peel puncture resistance (PPR) and development of yellow peel color in many citrus cultivars. Our objective was to determine the optimal time to apply GA for increasing juice yield of `Hamlin' sweet orange [Citrus sinensis (L.) Osb.]. Mature trees on sour orange (Citrus aurantium L.) rootstock were sprayed with ≈24 L of a solution of GA (45 g a.i./ha) and organo-silicone surfactant (Silwet, 0.05%). Trees were sprayed on 26 Aug., 9 Sept., 2 Oct. (colorbreak), or 13 Oct. 1997, or nonsprayed (control). Peel puncture resistance, peel color, and juice yield were evaluated monthly between Dec. 1997 and Mar. 1998. Fruit from trees sprayed with GA had peels with higher PPR and less yellow color than fruit of control trees for most of the harvest season. The effect of GA on PPR and peel color lasted about 5 months. Juice yield was usually numerically greater for GA-treated fruit than for nontreated fruit. Fruit treated with GA at color break had significantly greater juice yield when harvested in late February than fruit from control trees. Thus, GA applied at color break appears to be the most effective time for enhancing peel quality and juice yield of `Hamlin' oranges.
238 Isoperoxidase and Protein Patterns in Compatible and Incompatible Pear/Quince Graft Combinations
Authors: Gulen Hatice , Lim Chon C. , Arora Rajeev , Gulen Hatice , Kuden Ali , Krebs Stephen L. , Postman Joseph
Published: February 2019

The similarity or differences of peroxidase isozymes in rootstocks and scions may influence their graft compatibility. This study was conducted to identify peroxidase isozymes and/or other proteins that may be used as markers to predict compatibility between pear and various quince clones. `Bartlett' (BT) and `Beurre Hardy' (BH) pear cultivars were budded on 13 selected quince clones and quince A (QA) rootstocks; BT and BH cultivars are known to be incompatible and compatible, respectively, with quince root stocks. Bark and cambial tissues were taken from unbudded rootstocks, scions, and 4 cm above and below the graft union for isozyme analysis. Samples were collected 1, 2, 3, and 12 months after grafting. In addition, samples from the graft unions were also analyzed 12 months after grafting. Isozyme separation was performed by starch gel electrophoresis. Many isozyme bands were commonly observed in the two scions; however, one anodal peroxidase was detected in BH but not in BT samples. This isozyme was also detected in QA and in all but four quince clones. Protein profiles of bark tissues from QA and three pear scions (BT, `Bosc', and P. crassane) were determined using SDS-PAGE. In general, protein profiles of the three pear cultivars appeared remarkably similar; however, P. crassane (a compatible pear cultivar on QA) had a 63 kDa protein, which was absent in BT and faintly observed in `Bosc' (intermediate compatibility). Our results suggest that these isoperoxidase and polypeptide could be associated with pear/quince graft compatibility.
242 Developing a Chemical Delivery System in Tree Fruit Production
Authors: Ju Zhiguo , Duan Yousheng , Ju Zhiqiang
Published: February 2019

In China, one of the most serious problems to fruit growers is too much vegetative growth and too many pests and diseases during the growing season. Therefore, a large number of growth regulators, pesticides, and fungicides are used each year, which increases production costs and causes environmental pollution. To reduce the usage of agrochemicals, a device was invented to confine the treated area. Instead of applying chemicals directly to leaves, which may have reduced the efficiency by washing or UV degradation, the chemicals were injected directly to the truck of trees and transported through the xylem to the target organ, the leaf. Results showed that, to reach the same level of control, using plant regulators such as paclobutrazol, gibberellins, and ascorbic acid, the amount used could be reduced by 50% to 80%. The use of fungicides such as captan and diazinon could be reduced by 35% to 60%, and the use of pesticides such as vendex could be reduced by as much as 50%. Compared with the conventional method, the injection method showed three advantages: 1) It is economical in that production costs were reduced by about 40%, 2) It is efficient in that the same level of control was achieved using less chemicals (Due to the small acreage cultivated by family growers in China, the device could be installed within days and chemicals could be applied within hours.), 3) It is environmentally friendly because chemicals were not released throughout the orchard.
256 Evaluation of Phosphate Desorption Characteristics of Clay Minerals for Soilless Root Media
Authors: Oh Young-Mi , Nelson Paul V. , Hesterberg Dean L.
Published: February 2019

Soilless root media retain very little phosphate. This characteristic necessitates continual application of phosphate, which leads to excessive application and leaching. The phosphate desorption characteristics of synthetic hematite (a-Fe2O3), goethite (a-FeOOH), allophane (Si3Al4O12*nH2O), and a commercial alumina (Al2O3), previously determined for their maximum adsorption capacities, were evaluated to determine their potential for providing a low, constant soil solution phosphate supply with low phosphate leaching from soilless root media. The desorption isotherms of the clay minerals were obtained by introducing 10 mM KCl solution at 0.2 ml/min flow rate into a stirred flow reaction chamber loaded with clay adsorbed with phosphate at maximum adsorption capacity. The suspension in the reaction chamber was held at pH 6.4 during desorption. Effluent solutions were collected for phosphorus analysis until the equilibrium concentration of phosphorus in solution reached 0.05 mg•L-1. Adsorbed phosphorus at 0.05 mg•L-1 equilibrium concentration in solution was in the order allophane (19 mg•g-1) > alumina™ goethite (8 mg•g-1) > hematite (1.3 mg•g-1). The equilibrium concentration of phosphorus in solution over time showed that allophane releases phosphate for a longer time than the other clay minerals at a desirable soil solution concentration for plants, less than 5 mg•L-1. Among the clay minerals tested, allophane showed the most favorable potential to supply phosphate to plants in soilless root media.
337 Determining Suitable Chilling Conditions for Deciduous Fruit Trees in Iraq
Authors: Al-Kahafaji Makki A.
Published: February 2019

This study was conducted during two season (1993-1994) to formulate a suitable mathematical model to determine optimal chilling conditions for deciduous fruit trees from different areas of Iraq (Baghdad, Diyala, Karbala, and Naynawa). A hygrothermograph was utilized to record the average chilling temperature: Baghdad (571), Diyala (874), Karbala (548), and Naynawa (1206). Temperature information gathered 1982-1994 from weather forecasting records also proved beneficial to our study. The model designed for this project was then used to measure optimal chilling conditions of deciduous fruit trees in 11 areas of Iraq: 1000-1200 h in northern areas (Douhook, Sulaymaniyah, Arbeel Naynawa); 700-800 h in the north central areas (Al-Taameen, Salah al din, Diyala), 500-600 h in the middle and south centeral areas (Baghdad, Karbala, Babil, Al-Najaf, Wasit), and 200 h in the southern areas (Al Qadissiyah, Thi-qar, Misan, Basrah). The chilling temeperature differences recorded in the central areas were due primairly to variations in water surface and plant coverage. Temperature proved to be the determining factor for chilling hours accumulations recorded during the growing seasons.
339 Postharvest Physiological and Physico-chemical Responses of Jute (Chorchorus olitorius Linn.) to Various Temperature Conditions
Authors: Tulio Artemio Z. , Chachin Kazuo , Ueda Yoshinori , Ose Kimiko , Yamanaka Hiroyuki
Published: February 2019

The physiological and physico-chemical responses of jute, a tropical green leafy vegetable, to several temperature conditions were determined during postharvest storage. Jute were sourced from wholesale market and harvested from the university farm, packed in low-density polyethylene bags and stored at 1 to 30 °C and 1 to 20 °C, respectively, before it was analyzed for postharvest quality changes. There was no significant difference in the time-temperature tolerance of both leaves in all treatments. At 1 °C and 8 °C, both jute showed high sensitivity to chilling injury, which manifested by browning of the stems, darkening of young and mature leaves, wilting, and excretion of slimy substances. These symptoms developed within 3 to 9 days at 1 °C and 5 to 13 days at 8 °C, and it seems related with the decrease of ortho-diphenol content. The chlorophyll fluorescence of jute measured in terms of Fv: Fmax ratio decreased before the onset of browning and remained at lower levels during development of chilling injury at 1 and 8 °C. The ethylene concentration decreased after increasing for 1 day at 8 °C and before chilling injury occurred at 1 °C. However, at 15, 20, and 30 °C, both jute were more susceptible to yellowing with chlorophyll degradation and abscission of leaves due to senescing effect of high-temperature storage. Senescent symptoms were evident within 1 to 5 days at 30 °C and 3 to 7 days at 15 and 20 °C. Jute with stems partly immersed in water during storage had lower respiration rates at 1 and 8 °C due to its sensitivity to chilling injury manifested by wilting of leaves within 1 to 4 days of storage.
361 Quality Changes During Storage of Intact and Fresh-cut Cantaloupe Melon
Authors: Portela Silvina I. , Cantwell Marita I.
Published: February 2019

Although minimal processing increases the perishability of products, largely due to microbial decay, quality changes may be similar between tissues from intact produce and fresh-cut pieces. This study compared pulp quality changes of intact cantaloupe melons and of sanitized fresh-cut pieces (1.8 x 3-cm cylinders) during storage in air at 2.5 (cv. Corona) and 5 °C (cv. Corona and Durango) for 15 days. Quality evaluations included subjective (visual quality, decay, translucency, aroma, off-odor) and objective (color, firmness, SSC) measurements. At 5 °C, visual quality of the pieces was below the limit of salability by day 15 due to decay, whereas pulp from stored melons was excellent. Pulp from intact melons did not suffer from development of translucency as did the fresh-cut pieces. At 5 °C, pulp from intact fruit had higher aroma scores than pieces, but there were no differences in off-odor scores. At 2.5 °C there were no differences in the subjective quality measurements of pulp from intact or fresh-cut pieces. Pulp from intact fruit had higher chroma (at 2.5 and 5 °C) and L* (only at 5 °C) than the pieces after 6 or 15 days, depending on the variety. There were no differences in hue between intact and fresh-cut pulp. Pulp from intact and fresh-cut pieces had similar firmness changes and SSC during storage at 2.5 and 5 °C. We conclude that pulp of intact fruit and fresh-cut pieces had similar quality up to 15 days at 2.5°C; but at 5 °C, the fresh-cut pieces lost intrinsic quality (visual quality, aroma, and color) before the pulp of intact fruit did.
364 Controlled-Atmosphere Storage of Fresh-cut Spinach at Various Temperatures
Authors: Izumi Hidemi , Nakatani Tetsuya , Ogikubo Hiroki
Published: February 2019

`Sunbest' spinach leaves were stored in air or controlled atmosphere (CA) containing 3%, 6%, and 10% CO2 combined with 0.5% O2 at 0, 10 and 20 °C. Carbon dioxide production and O2 consumption of spinach leaves decreased in CA by about 50%, 40%, and 65% relative to those in air at 0, 10 and 20 °C, respectively. The rates in the different CA were similar. The respiratory quotient (RQ) of spinach leaves held in CA was slightly higher than that held in air at 0 and 20 °C. CA inhibited the growth of aerobic mesophilic bacteria and lactic acid bacteria at all temperatures, with the inhibition being greater in 6% or 10% CO2 with 0.5% O2. The ascorbic acid content at the end of storage was higher in spinach leaves held in air than in CA at all temperatures except 10% CO2 with 0.5% O2 at 20 °C. A slight or no off-odor was emitted by all spinach leaves. At 20 °C, spinach leaves held in 6% and 10% CO2 with 0.5% O2 developed more off-odor than those in air. These results indicate that the CA of 3%-10% CO2 and 0.5% O2 was beneficial in reducing respiration rate and microbial growth of spinach leaves at 0, 10, and 20 °C but accelerated ascorbic acid loss at all temperatures and induced off-odor at 20 °C.
390 Controlled-Atmosphere Tents for Storage of Fresh Blueberries in Conventional Refrigerated Rooms
Authors: Leyte Jerry C. , Forney Charles F.
Published: February 2019

A plastic tent was designed and constructed for the controlled atmosphere (CA) storage of fresh blueberries. The CA tent was suspended from pallet racking in a standard cold room and held two standard pallets stacked 6 feet high with flats of packaged blueberries. The tent was sealed with two air-tight zippers and a small water trough, resulting in an air-tight chamber that successfully maintained CA storage environments. The CA tent was easily set up and removed to allow flexibility in use of storage space. To provide efficient use of storage space, tents could be stacked two or three high on pallet racking. The tent was easily loaded and unloaded by a single person using a forklift. CA tents provide an economical alternative to traditional CA rooms for the storage of small quantities of fresh blueberries and allows greater flexibility in marketing than traditional CA storage rooms. CA tents are suitable for the storage of other fresh produce that benefits from CA environments.
396 Suppression of Green Mold on Grapefruit during Refrigerated Storage in Altered Atmospheres
Authors: Shellie Krista C.
Published: February 2019

Green mold, a predominant disease of citrus fruit, develops when spores of Penicillium digitatum infect extant wounds in fruit epidermal tissue. Development of green mold during shipping limits the distance grapefruit can be surface transported. The objective of this research was to evaluate whether altering the atmosphere during refrigerated storage could suppress development of green mold. In the first two experiments, growth of green mold was evaluated after fruit were stored in ultra-low oxygen (0.05 or 1 kPa) at 14, 16, or 18 °C for up to 21 days. In the last two experiments, grapefruit were stored for 14 or 21 d at 12, 13, or 14 °C in atmospheres containing 2, 5, or 10 kPa oxygen with or without 2, 5, 10, or 20 kPa carbon dioxide. In all experiments, grapefruit were inoculated with 10 or 20 μL of a spore suspension of P. digitatum. Decay progression after storage was monitored by measuring the diameter of the lesion in cm at the demarcated site of inoculation or by subjectively rating percent decayed fruit surface area. Grapefruit not inoculated with P. digitatum had no visible symptoms of green mold. Grapefruit stored under controlled atmosphere had less fruit surface covered with mycelium (5% to 64%) than grapefruit stored in air. Inoculated grapefruit stored in 0.05 kPa oxygen for up to 14 d at 14 or 18 °C had no visible symptoms of green mold upon removal from cold storage, but developed a characteristic green mold lesion after 5 additional days of storage in air at ambient temperature. Results suggest that refrigerated controlled-atmosphere storage combined with wax and a fungicide can enhance control of green mold during shipping.
407 Regulation of Carbon Flux as a Function of O2 and CO2 Atmospheres in Asparagus Tips
Authors: Silva S.M. , Herner R.C. , Beaudry R.M.
Published: February 2019

The purpose of this work was to investigate the influence of O2 and CO2 partial pressures on glycolytic carbon flux, phosphorylated intermediates, phosphate, pyrophosphate, and phosporylated nucleotides in asparagus spears tips stores at 1 °C. The effects of CO2 (0, 5, 10, and 20 kPa) combined with O2 pressures ranging from 0.1 to 16 kPa (1% O2 = 1.013 kPa O2 at 1 atm) were investigated. Spears were enclosed within a low-density polyethylene (LDPE) package (for the 5-, 10-, and 20-kPa CO2 treatments) having a surface area of 462 cm2 and enclosed in 1.95-L glass jars. Low O2 enhanced the interconversion of phosphoenolpyruvate (PEP) to pyruvate (PYR) and F6P to F1,6P2 relative to high O2. When spears tips at 16 kPa O2 were compared to those at harvest, little change occurred in the adenylate or phosphate pools. PPi and ATP contents decreased as the O2 partial pressure declined below 16 kPa O2. In general, as CO2 increased, PPi and ATP decreased, while Pi, ADP, and AMP increased. The adenylate energy charge (AEC) declined with a decline in the O2 partial pressure, declining most rapidly below 2 kPa O2. Low O2 reduced AEC relative to high O2. Increasing CO2 partial pressure reduced AEC, an effect not evident at lower O2. The data suggest low O2 and elevated CO2 impair oxidative phosphorylation and induce nonsustaining carbon metabolism, which may limit asparagus spear survival under O2-deficient conditions.
408 Atmospheric Oxygen Level Affects `Beauregard' Sweetpotato Respiration Rate, Fermentation Products, and Sugar Composition
Authors: Kilili Anthony , Picha David H. , Huang Yuehe
Published: February 2019

`Beauregard' sweetpotatoes (Ipomoea batatas L. Lam) were stored under a continuous flow of 0%, 1%, 1.5%, 2%, 5%, 10%, or 21% O2 (balance N2) for 14 days. Respiration rate was significantly lower at 1.5%, 2%, 5%, and 10% O2 compared with 21% O2, while respiration at 0% and 1% O2 was higher than at 1.5%, 2%, 5%, and 10% O2. Respiration rate at 0% O2 remained high for several days after exposure to air while that at 1.5%, 2%, 5%, and 10% O2 increased rapidly to equal that of 21% O2. Ethanol and acetaldehyde accumulated rapidly at 0% and 1% O2 but were lower at the other O2 levels. Ethanol increased 16- and 4-fold after 14 days of storage at 0% and 1% O2, respectively, compared to 21% O2. In addition, acetaldehyde increased 11- and 8-fold at 0% and 1% O2 respectively, compared to 21% O2. Sucrose and total sugar concentration increased under low O2 concentration while reducing sugars (fructose and glucose) and pH decreased.
415 Fertilizer Source and Medium Composition Affect Growth of Moth Orchid
Authors: Wang Yin-Tung , Konow Elise A.
Published: February 2019

Vegetatively propagated Phalaenopsis Atien Kaala `TSC 22' plants 10 cm in leaf spread were potted in a medium that consisted of either 100% fine grade Douglas fir bark or a mixture of 70% fir bark and 30% sphagnum peat. Plants were fertigated at each irrigation with 10N-13.1P-16.6K (10-30-20), 20N-2.2P-15.8K (20-5-19), 20N-8.6P-16.6K (20-20-20), or a 2N-0.4P-1.7K (2-1-2) liquid fertilizer at a common N rate of 200 mg•L-1. After 1 year in a greenhouse, plants grown in the bark/peat medium produced more leaves and had heavier fresh weights and larger total leaf areas than those in 100% bark. In the bark medium, the 20N-2.2P-15.8K fertilizer resulted in best plants, despite its low P concentration (22 mg•L-1). When grown in bark/peat, the two fertilizers (20N-2.2P-15.8K and 20N-8.6P-16.6K) containing urea as part of their N source (10% and 52%, respectively) resulted in plants with 40% to 50% heavier shoot fresh weight and 40% larger leaf area than the other fertilizers. With any given fertilizer, plants had similar root weights in both media. Media and fertilizers had limited or no effect on the concentrations of minerals in the second mature acropital leaves except P, the concentration of which nearly doubled in leaves of plants grown in 100% bark. Water extracts from the bark/peat medium had lower pH, higher EC, and elevated levels of NH4-N, Ca, Fe, Na, Cl, B, and Al than those from 100% bark. Exacts from the bark medium did not have detectable levels of NO3-N, whereas extracts from the bark/peat medium all had similar levels of NO3-N, regardless of which fertilizer was applied.
418 Properties of Soils in which Sticherus flabellatus Naturally Occurs
Authors: Cras Melanie C. , McConchie Robyn
Published: February 2019

Sticherus flabellatus (R.Br.) St John, commonly known as Umbrella Fern, is a member of the Gleichenaceae family. Sticherus flabellatus is found on the N.S.W. coast and ranges, Qld, and eastern Victoria in Australia, as well as in New Zealand and New Caledonia. Fronds emerge from underground creeping rhizomes, forming large colonies in sheltered sites in moist gullies and creek banks in open forest. Propagation of the genus Sticherus has previously been relatively unsuccessful. The ferns are difficult to raise from spore and established specimens resent major disturbance to their roots, therefore making them hard to transplant. As a result of these difficulties the properties of the soil in which S. flabellatus grows naturally were investigated to determine the specific requirements for successful growth. Soil was collected from naturally occurring stands of S. flabellatus growing in a diverse range of sites within and on the periphery of the Sydney Basin. At each site a core of soil (12 cm diameter x 12 cm high) was taken at ≈0, 25, and 50 m along a line transect situated within a S. flabellatus stand, providing three replicates for each site. Physical and chemical properties were determined for each site. Particle size and consequently soil texture were determined using the hydrometer method. Electrical conductivity (EC) and pH readings were taken in a 1 soil: 5 water solution. pH readings were also taken in a 1 soil: 5 CaCl solution. Available P was analysed using the Bray (no. 2) method and organic carbon through colorimetric measurement after dichromate acid digestion. We found that S. flabellatus prefers growing in quite acidic soil with an average pH of 5.2 in a water solution and 4.0 in a CaCl solution. The EC readings were also significantly low with a mean reading of 37.0 μS•cm-1. Organic carbon was measured at a mean of 2.4% and available P at 4.1 mg•kg-1 of soil. Using the International Soil Texture Triangle the soil in which S. flabellatus is found growing can be classified as sandy. The average sand content was 87.6%, clay 6.8% and silt 5.5%. These results show that S. flabellatus grows naturally in highly acidic, nutrient poor sandy soils that contain only minimal amounts of organic carbon and phosphorus. Therefore this needs to be taken in consideration when trying to successfully propagate the fern.
419 Knowledge, Attitudes, and Perceptions of Journalists for Newspapers in Metropolitan Markets in the United States Regarding Food Biotechnology
Authors: Vestal Tom Andrew , Briers Gary E.
Published: February 2019

This study enhances knowledge of and information for food systems educators and industry about multiplying their efforts—enlisting collaboration of journalists and the social institution of mass media—in educating consumers about food biotechnology. The focus of this study (diffusion of innovations of food biotechnology) may change behaviors of researchers, agricultural educators, and those in the food biotechnology industry. The researchers investigated journalists' knowledge about, attitudes toward, and perceptions of food biotechnology. Eighty-eight journalists practicing at the nation's largest newspapers and representing “beats” of business, environment, agribusiness, features, food, health/medical, and science/technology provided data for the study. A researcher-developed instrument measured journalists' knowledge, journalists' attitudes (acceptance of genetically modified organisms, acceptance of food biotech practices, effects of biotechnology, level of importance of research, faith in sources, level of importance placed on investigative reporting style, and fear of using food biotechnology), and journalists' perceptions regarding acceptance of food biotechnology as a farm practice. Major findings were journalists' knowledge was low (mean 30.2%), most journalists considered genetic modification of plants as “acceptable,” journalists had greatest faith in “university scientists” and “health professionals” as sources of biotechnology information, journalists do further investigation and interpretation of information given by sources based on their faith in the source, journalists believed that farmers would accept food biotechnology more rapidly than consumers, journalists with higher perceived scientific knowledge had greater acceptance of genetically modified organisms, journalists with more knowledge about biotechnology saw fewer obstacles to acceptance of food biotechnology; and “Writers” rather than “Editors/Managers” accepted more readily genetically modified organisms, had greater faith in sources, had less fear of using food biotechnology, and perceived a more rapid rate of acceptance of food biotechnology as a farm practice.
424 Use of GPS in Golf Course Planning
Authors: Harp Derald A.
Published: February 2019

A major problem in golf course construction is trying to optimize the use of existing vegetation, especially trees. In North Central Texas, this is made more difficult by the predominance of post oak (Quercus stellata), a tree that declines severely when cultural conditions are modified. The purpose of this project was to create a map using GPS technology of the existing trees, before final planning and construction of the golf course. In addition to the map, a database was created which would be used for future maintenance and management decisions. The GPS equipment consisted of a Trimble PRO-XRS GPS receiver and Trimble TDC-1 data logger and a Laser Atlanta laser rangefinder. Information collected for the database included tree number, latitude, longitude, number, identification, caliper, estimated height, and quality. Quality ratings were defined as 1) specimen, 2) good, 3) fair, 4) poor, 5) unacceptable. Tree numbers were placed on each tree rated above unacceptable, using metal tree tags. Height estimates were made using the vertical offset feature of the GPS equipment. Base maps were created using Pathfinder Office. Hard copy maps were printed, and digital copies were saved in raw and.dxf format for importation into AutoCAD. This map was combined with existing course plans and adjustments were made to save as many specimen trees as possible. Raw information was also imported into a Microsoft Access 97 database. This project created a database and maps that will provide important information in the future, and the development of the course with minimal loss of specimen trees.
437 Changing Demographics of Nontraditional Students in an Off-campus Horticulture Degree Program
Authors: Fitzpatrick George E. , Klock-Moore Kimberly A.
Published: February 2019

Over the 10-year period of 1987-1997, the demographics of the student population enrolled in the University of Florida off-campus BS degree in horticulture program at Fort Lauderdale have changed. Average student age has increased from 35.5 years to 38.1 years. Age range has increased from 22 to 54 years to 21 to 75 years. Age distribution changes have been most notable. In 1987, the age of the student population was normally distributed, whereas by 1997 the distribution had become bimodal, with one mode in the age group 26 to 30 and the other mode in the 41 to 45 age group. Estimated median one-way distance traveled to attend classes has not changed significantly, from 13.2 miles (range 3.9-89.8 miles) in 1987 to 14.2 miles (range 1.0-59.8 miles) in 1997.
440 A Comparative Study on Flavor and Nutritional Attributes of `BetaSweet' Maroon Carrot (Daucus carota L.)
Authors: Lazcano Carlos A. , Pike L.M. , Yoo K.S.
Published: February 2019

A new designer carrot, `BetaSweet', with high levels of anthocyanin, betacarotene, and crispy texture was developed by the Vegetable Improvement Center at Texas A&M Univ. The new carrot contained low levels of low-volatile terpenoids, responsible for the harsh flavor in carrots and high levels of reducing sugars. Carotenoid content increased with carrot maturity and stabilize at 120 days after sowing for orange and maroon genotypes; however, the maroon genotype was 35% higher than the orange cultivar. Anthocyanin, a cancer preventive compound and not detected in ordinary orange carrots, is present in `BetaSweet' maroon carrot with 89.8 mg·100 g-1 of fresh weight. High percentage of soluble solids and succulence in the maroon cultivar seemed to contribute to the favored sweetness perception by consumers. A consumer taste panel showed a significant difference between orange and maroon genotype for sweetness, texture, and overall carrot flavor.
447 Nutrient Removal by Five Ornamental Wetland Plant Species Grown in Treatment-production Wetland Biofilters
Authors: Holt Thomas C. , Maynard Brian K. , Johnson William A.
Published: February 2019

We assessed the capacity for nutrient removal of ornamental water garden plants being grown in treatment-production wetland biofilters. Plant biomass, nutrient uptake, tissue nutrient content, and production potential were compared for five popular ornamental water garden plant species: Typha latifolia L., Iris pseudacorus L., Phalaris arundinacea L. `Picta', Canna glauca L., and Colocasia esculenta (L.) Schott. Plants were grown in triplicate 0.3 m2 × 0.3 m, deep gravelbed mesocosms fed with 20N-20P-20K Peter's fertilizer (Scotts-Sierra Horticultural Products Co., Marysville, Ohio) reconstituted to 100 ppm N. After 120 days, mean species total biomass ranged from 1.4 to 5.6 kg·m -2, while producing 105 to 206 divisions per square meter. Growth for Canna and Colocasia was greatest, while Typha produced the most divisions. Mean tissue N and P concentrations ranged from 18 to 29 and 2.1 to 3.0 mg·g -1, respectively. Maximum plant accumulation of 144 g N/m 2 and 15.6 g P/m2 accounted for 70% of the N and 15% of the P supplied by fertilizer. Mean removal of total N and P ranged from 42% to 90% and 18% to 58%, respectively, and was positively correlated with plant biomass. Nutrient removal ability was ranked as Canna = Colocasia > Typha > Iris = Phalaris.
464 Distribution of Sugars in Sweet Corn
Authors: Russo V.M. , Smith T.
Published: February 2019

Sweet corn (Zea mays L.) kernels are sinks, and sugars found in kernels must be translocated from a source. Stalk tissues can act as a source and a sink as sweet corn plants age. Quantity and types of sugars present in various sweet corn tissues during plant development are not well documented. Concentrations of fructose, glucose, sucrose, and their total were determined in the ninth stalk internodes (I9) from the 12-leaf stage (V12) to fresh-market maturity (R3) in sweet corn cultivars carrying either the su1se1, su1, or sh2 endosperm genotype. Developing ears were sampled at tassel emergence (VN) and silking (R1). Kernels and cob tissue were sampled separately at blister stage (R2) and R3. Correlation analysis was performed on concentrations of sugars at all developmental stages. In I9, from V12 to R3, levels of fructose and glucose declined and sucrose increased. In developing ears, concentrations of fructose and glucose increased from VN to R1. Concentrations of sugars in cobs in all cultivars were generally the same at R2 and R3. In kernels from R2 to R3 in the su1se1 cultivar, glucose decreased while the other sugars were unchanged; in the su1 cultivar, fructose decreased while levels of the other sugars stayed the same; and in the sh2 cultivar, fructose decreased, glucose was unchanged and sucrose increased. Correlation analysis suggested that the cultivars moved sugars to the kernels differently. The pattern of movement of sugars to kernels was most complex in the su1se1 cultivar than in the su1, which was more comlex than in the sh2 cultivar. Knowing how sugar content changes in the plant may be used to predict sugar content in kernels.
468 Effect of Hydrogen Cyanamide (Dormex) and Ethephon (Ethrel) on Fruiting of `Surecrop' Peaches
Authors: Powell Arlie A. , Pitts James , Boozer Bobby
Published: February 2019

Early flowering of peach in the southeastern United States can result in annual crop loss as a result of late winter-early spring freezes. In peach and other prunus, a fall application of ethephon delays flowering several days; however, delayed harvest and smaller fruit size of certain varieties may occur. Hydrogen cyanamide replaces the late stage of chilling in peach but can also advance bloom and harvest date while maintaing or enhancing fruit size. A randomized complete-block experimental design using 13-year old `Surecrop' trees was used to evaluate whether hydrogen cyanamide could offset the delayed harvest and smaller fruit size disadvantages of using ethephon without advancing bloom dates. Treatment combinations of ethephon (at 20%, 50%, and 90% of required chilling) and hydrogen cyanamide (at 90% to 100% of required chilling) were applied as whole-tree foliar sprays to near point of drip. Although not significant, there were trends toward hydrogen cyanamide overcoming both smaller fruit size and delayed harvest induced by ethephon. This agrees with an earlier study using `Redhaven'. Dormex negated the late flowering effects of ethephon applied at 20% chilling but did not cause flowering earlier than the control.
471 Tomato Fruit Treated with 1-methylcyclopropene Provide Adequate Non-ripening Controls in Low-temperature Storage Experiments
Authors: Almeida Domingos P. F. , Huber Donald J.
Published: February 2019

Chilling injury limits the postharvest handling of many fruit and vegetables. In low-temperature storage trials, control treatments typically consist of fruit stored above the injury threshold. Since chilling exposures for tomato fruit often exceed 2 weeks, controls stored above the threshold continue to ripen, confounding comparisons with fruit maintained at low temperatures. In this study, the ethylene action inhibitor 1-MCP was used to arrest ripening to permit more valid comparisons between fruit stored under the two temperature regimes. Mature-green tomatoes were treated with EthylBloc and then stored at 5 or 15 °C for 2 or 3 weeks after which time the fruit stored at 5 °C were transferred to 15 °C to allow the expression of injury symptoms. 1-MCP inhibited ripening of fruit stored at 15 °C for 2 to 3 weeks. Color, pericarp firmness, and pectin solubilization of MCP-treated fruit stored at 15 °C remained at the values of mature-green fruit, validating their use as controls for these physiological characteristics. After 2 to 3 weeks at 15 °C, MCP-treated fruit resumed normal ripening. Comparing the fruit removed from low-temperature storage with nonripening controls at 15 °C revealed that storage at 5 °C for 2 to 3 weeks decreased the hue (yellowing) but did not affect chroma or lightness, maintained firmness, and did not affect pectin metabolism. Electrolyte leakage increased or remained unaffected by cold storage. MCP-treated fruit had slightly higher electrolyte leakage than non-MCP-treated fruit after storage at either 5 or 15 °C. We conclude that MCP-treated fruit provide adequate controls in experiments designed to study many aspects of low-temperature storage.
474 Effect of Vigor and Duration of Chilling on Heat Shock-induced Chilling Tolerance in Cucumber Radicles
Authors: Mangrich Mary E. , Saltveit Mikal E.
Published: February 2019

Chilling 10-mm cucumber (Cucumis sativus L. `Poinsett 76') radicles at 2.5 °C reduced their subsequent growth during 3 days at 25 °C. The reduction in radicle growth was linear for 1 to 3 days of chilling but then increased substantially until subsequent radicle growth was all but eliminated by 6 days of chilling. Heat shocks of 40 °C applied for 4 to 12 min increased chilling tolerance such that 4 days of chilling caused only a 36% decrease in radicle growth compared to 66% for seedlings not heat shocked, which brought the response in line with the responses of the non-heat-shocked seeds chilled for 1 to 3 days. Eight-minute heat shocks applied before 5 days of chilling resulted in a 45% inhibition of subsequent growth, compared to 82% for chilled non-heat-shocked controls. Heat shocks applied before 3 days of chilling did not result in a significant increase in subsequent growth compared to the non-heat-shocked controls chilled for 3 days. Heat shocks were only able to protect that part of radicle growth that was in excess of the linear decrease in radicle growth. There appears to be two effects of chilling on radicle growth. The first is linear and cannot be affected by heat shocks. The second is much more severe and can be prevented by heat shocks. Seeds were selected for three categories of vigor according to the rate at which their radicles grew to 10 mm. Seeds classified with different vigors neither responded significantly differently to 3 days exposure to 2.5 °C nor did they respond differently to chilling stress following application of heat shocks.
478 Preharvest Calcium Application and Its Benefit on Vase Life of Lupinus havardii Watts Cut Flowers
Authors: Valenzuela-Vazquez Mario , Picchioni Geno A.
Published: February 2019

Lupinus havardii has gained popularity as a potentially new and unique cut flower species, but its compound, ethylene-sensitive inflorescences (racemes) undergo rapid senescence and deterioration on cutting. The purpose of this study was to evaluate the influence of Ca culture solution applications on L. havardii cut-flower longevity. Four supplemental Ca treatments were incorporated into the nutrient solution (0, 2.5, 5.0, and 10.0 mM Ca using CaCl2), with four replications in a randomized complete-block design. Raceme Ca concentration increased with increasing Ca application, ranging from a low 5300 mg·kg-1 dry weight (0 mM supplemental Ca) to a high of 7500 mg·kg-1 (10.0 mM supplemental Ca). Calcium application deferred the daily loss in raceme fresh weight (FW) for up to 10 days of vase life in a concentration-dependent manner (P < 0.01), with the effect most pronounced between 5 and 9 days following cutting (average FW of 72% and 83% of day zero values for the control and 10.0 mM Ca, respectively, with 2.5 and 5.0 mM treatments intermediate). The cut racemes of L. havardii are model organs for spatially and sequentially organized postharvest development, with continued, 6-day postcutting life including 4-fold increases in cell permeability of basal, most mature flowers, marginal but significant increases in cell permeability of the most recently expanded flowers, and a 50% increase in total flowers number resulting from inflorescence expansion. Preliminary data indicate that manipulation of Ca nutrition may be a viable, inexpensive, and environmentally safe alternative to silver-based compounds currently in use for the vase life extension of L. havardii inflorescences.
484 Effect of Viral Infection and Clonal Variability on Sweetpotato Yield and Quality
Authors: Wallace Heather L. , La Bonte Don R. , Clark Christopher A.
Published: February 2019

Virus infections and genetic mutations have been implicated in the decline of sweetpotato yield and quality. Virus-tested mericlones were derived from 12 infected clones of `Beauregard' sweetpotato by meristem-tip culture. Field studies were conducted to evaluate yield differences between the virus-tested and the virus-infected plants of each respective clone. After a 90-day growing period, the storage roots were harvested, weighed, and analyzed with a colorimeter to gauge color of skin and flesh. Yield was 7% to 130% greater in virus-tested mericlones compared to their respective virus-infected clone. Data also show these 12 virus-tested mericlones vary in yield by up to 118%. This suggests genetic differences between clones greatly affect yield. The virus-tested mericlones also show a more desirable darker-red hue for skin and flesh than the virus-infected clones. The incorporation of virus-tested material into foundation seed programs could potentially increase yield and quality with little added expense to growers, thereby netting a higher return on their crop.
496 Public Perception in Determining Water Management in Urban Landscapes
Authors: Lockett L.L. , McKenney C.B. , Auld D.L.
Published: February 2019

Many segments of private industry use data gathered from public attitude and opinion research as an integral part of the planning, program development, and evaluation process. These basic techniques were used to determine public perception of five species of Texas native plants grown at three irrigation rates under xeriscape conditions. Nearly half of the average annual residential water costs go to lawns and gardens. Minimizing the amount of water used in irrigation could provide significant savings of money and a precious natural resource. The complexities of measuring social attitudes, how to develop a valid survey instrument, methods of analyzing survey data, and appropriate interpretation will be discussed. Use of public perception could be a powerful tool in developing water conserving technologies.