bluuebunny/crossref_metadata_2025 huggingface dataset:
578 The Influence of Reflective Film on Red Skin Color and Maturity of Peaches in South Carolina
Authors: Layne Desmond R. , Jiang Zhengwang , Rushing James W.
Published: February 2019

Replicated trials were conducted in summers of 1998 and 1999 at several commercial orchards to determine the influence of a metalized, high-density polyethylene reflective film (SonocoRF, Sonoco Products Co., Hartsville, S.C.) on fruit red skin color and maturity of peach cultivars that historically have poor red coloration in South Carolina. At each site there were two experimental treatments: i) Control; and ii) Reflective Film (RF). RF was laid 2 to 4 weeks before anticipated first pick date by laying a 5-ft-wide strip of plastic on either side of the tree row in the middles. Treatment blocks at a given farm ranged from 0.5 to 1 acre in size and each treatment was replicated four times at each site. At harvest, two 50-fruit samples were picked from each block per treatment. All fruit were sized and visually sorted for color (1 = 0% to 25%, 2 = 26% to 50%, 3 = 51% to 75%, and 4 = 76% to 100% red surface, respectively). A 10-fruit subsample was selected following color sorting and evaluated for puncture pressure and soluble solids concentration (SSC). All cultivars tested (CVN1, Loring, Bounty, Summer Gold, Sun Prince, Cresthaven, and Encore) experienced significant increases in percent red surface when RF was used in 1998 and 1999. This color improvement ranged from 16 to 44% (mean = 28%). On average, fruits from RF were 0.8 lb softer and had 0.3% higher SSC than control fruits. Growers harvested more fruit earlier and in fewer picks for RF. Fruit size was not affected by RF. The influence of RF on orchard microclimate and quality and quantity of reflected light will be discussed.
580 GA Application Timing in Fall and Winter Influences Bloom Period, Fowering Intensity, and Final Crop in Florida `Navel' Orange
Authors: Stover E.W. , Ciliento S.M. , Yang X.
Published: February 2019

In Florida's subtropical climate, citrus floral induction is primarily stimulated by cool weather in the fall and winter. Frequently, inductive periods are separated by warm conditions conducive to bud development, resulting in prolonged and multiple bloom. Large variability in date of fruit-set creates an array of problems, and prolonged bloom contributes to severity of postbloom fruit drop. GA applied during the inductive period inhibits bloom in citrus. This study was conducted to determine whether different GA application timings could shift bloom intensity and duration to reduce problems associated with prolonged bloom. GA was applied via airblast sprayer to mature `Navel' on sour orange rootstock near Ft. Pierce, Fla., at 49.4 g GA/ha, 0.05% Silwet L-77, and 2340 L/HA spray volume. Six single-tree experimental units per treatment were blocked by size and vigor in a randomized complete block design. Treatments were time of GA application: 23 Nov. 1998; 17 Dec. 1998; 6 Jan. 1999; 25 Jan. 1999; 23 Nov. and 17 Dec.; 23 Nov. and 25 Jan.; 6 Jan. and 25 Jan.; and a control. Bloom began one month earlier on trees that received the two January applications compared to trees that received GA on 23 Nov. and 17 Dec.. Trees sprayed 25 Jan. (or 6 Jan. and 25 Jan.) had 2 weeks shorter bloom duration compared to controls. Total flowering on GA-treated trees ranged from 13% to 55% of the controls. Single GA applications on 17 Dec. and 6 Jan. increased fruit yield at harvest by 42% and 25%, respectively, while GA on 6 and 25 Jan. yielded 27% less than controls. All other timings had no effect on yield.
583 Scaling-up Heat-balance Sap Flow Sensors for the High Flow Rates of Mature Grape Vines
Authors: Tarara J.M. , Ferguson J.C.
Published: February 2019

Management strategies like “deficit irrigation” in wine grapes require accurate, reliable information on vine water use, making direct measurements of vine transpiration highly desirable. The heat-balance sap flow method has the advantages of being non-invasive and requiring no other calibration beyond a zero-flow set. Potential violations of the method's assumptions were dealt with and the heat balance method successfully applied to mature grape vines under conditions of extremely high sap flow. Greenhouse studies suggested that vines transpire at night, up to 9.5% of the total 24-h water loss, thus violating the zero-flow assumption for setting the gauge constant. Using a predetermined gauge constant caused smaller errors than using daily, pre-dawn constants set in situ. The steady-state assumption was violated only in early and late hours of the day, and the inclusion of a term to account for the change in heat stored by the stem only marginally improved daily estimates of water use. The assumption of radially uniform temperature across the heated stem segment is violated at very high flows (e.g., >700 g·h–1), but can be corrected for by using wider heaters and adjusting the placement of thermocouples. For a mature, potted vine in the greenhouse, the maximum absolute error in cumulative daytime water use between a sap gauge and a precision load cell was about –10%, with the gauge almost exclusively underestimating water loss. A custom-built, 20-gauge system was run continuously in the field for 90 days. Vine-to-vine variability in water use was not accounted for by normalizing sap flow by leaf area, suggesting that it is critical to include in any field study the largest number of gauges that are technically feasible.
585 Rooting Hardwood Cuttings of Vitis aestivalis `Norton'
Authors: Keeley Kathryn , Preece John E.
Published: February 2019

Hard-to-root hardwood cuttings of Vitis aestivalis `Norton' were collected during Feb. 1999. Cuttings had three nodes and were 10 to 15 cm long. Prior to treatments, cuttings were submersed in a solution of 9.5 g/1L of ZeroTol (a mixture of hydrogen dioxide and peroxyacetic acid). The bottom two nodes were placed into 1 vermiculite: 1 perlite (by volume) and set under mist in the greenhouse at of 20/15 °C day/night). About 5 weeks after treatment, number of roots and root length data were collected. The bottom 2 cm of cuttings in one experiment received a 30-s dip in 0, 2500, 5000, 7500, or 10,000 mg/L IBA and/or NAA to determine the effects of these treatments on rooting of hardwood cuttings. IBA and NAA are not significantly different, however there was a positive linear relationship between rooting and concentration of auxin. As concentration of auxin increased, mean number of roots increased. In additional experiments, cuttings treated with 0 or 5000 mg/L of IBA were compared based on timing after harvest of cuttings and treatment. Of the cuttings treated and placed under mist on 26 Mar. 1999, 30% of the control cuttings rooted and 50% of the cuttings treated with 5000 mg/L rooted. Two weeks later, 65% and 55% of the cuttings treated with 5000 mg/L rooted respective to the 0- and 5000-mg/L treatments. One week later (14 Apr. 1999), 77.5% and 72.5%, respectively, rooted. This suggests that timing after harvest for placing the cuttings in a propagation bed is important for increasing the rooting percentage of `Norton' hardwood cuttings.
593 A Lightweight, Hand-operated Pressure Chamber for Determining Plant Water Status
Authors: Shackel Ken , Paige David
Published: February 2019

In a number of tree crops, we have found that the water potential of lower canopy, nontranspiring leaves, measured with the pressure chamber at midday (midday stem water potential), is an excellent index of plant water stress and can be used for irrigation scheduling. Because stem water potential is typically much higher than transpiring leaf water potential, a lower pressure is required for the measurement, allowing us to design and build a lightweight device that could be easily operated by hand. The prototype was designed for pressures up to 2 MPa, which is sufficient for most irrigation conditions. A number of design features were incorporated into the sealing gland to eliminate the need for retightening during the pressurization process, reduce the amount of tissue external to the pressure chamber, and allow a greater visibility of the petiole. Identical values to those obtained with the standard, compressed nitrogen pressure chamber were obtained over the entire 2-MPa range, and the time required using either device under field conditions was the same (about 1 min per measurement). A number of alternative protocols were tested, and we found that even substantial recutting of the petiole had no influence on the measured water potential, contrary to popular belief. We also found that the same sample could be remeasured multiple times (five), with no net change in the water potential, allowing the measurement to be checked if necessary. This device should be of great utility in field irrigation management.
598 Response of Apple Rootstocks to Soil Compaction
Authors: Ferree David C.
Published: February 2019

Container-grown apple trees on a range of rootstocks were exposed to different levels of soil compaction created by changing soil bulk density. In 1998, with soil bulk densities of 1.0, 1.2, and 1.4, there was no interaction of rootstock and soil compaction for shoot growth of `Melrose' trees on 7 rootstocks. However, in 1999, with soil bulk densities of 1.0 and 1.5, a significant interaction on shoot growth did occur with six rootstocks. Shoot length of trees on M.9, M.7, and G.30 were less influenced than G.16, M.26 and MM.106. A bulk density of 1. 5 caused a decrease in dry weight of shoots, leaves, and roots of trees on all rootstocks. Compacted soil resulted in a decrease in leaf concentration of K and B and an increase in Mg and Mn.
600 Maintaining Yields In Hedgerow Almond Production
Authors: Edstrom J.P. , Connell J. , Krueger W. , Reil W. , Hasey J. , Yeager J.
Published: February 2019

Four tree training methods have been evaluated since 1979 in California for their affect on yield of “Nonpareil” ctv. almond [Prunus dulcis (Mill.) D.A.Webb] in a tightly spaced “Nonpareil”/”Price” ctvs 1:1 hedgerow planting. Four variations of open center training began at the first dormant pruning in a 2.2 × 6.7-m spacing (667 trees/ha): 1) Temporary Hedge—trees trained to three primary scaffolds, standard pruned with alternate trees gradually whisked back to allow space for permanent trees and then removed at 8th year leaving 4.4 × 6.7-m spacing(333 trees/ha); 2) Permanent Hedge—trees trained to three scaffolds, standard pruned at 2.2-m spacing; 3) Two-Scaffold Hedge—Trees trained into “perpendicular V” two scaffold configuration, standard pruned at 2.2-m spacing; 4) Unpruned Hedge—Trained to three scaffolds then left essentially unpruned at 2.2-m spacing. Replicated yield data accumulated over 15 years shows no difference in production between the three permanent 2.2-m hedgerow methods. Yield for the Temporary Hedge, however, declined 30% the year following alternate tree removal. Adequate canopy expansion resulted in some regained nut production, but yields never recovered and remain 20% below the permanent hedge treatments 13 years post-removal. Observations indicate considerable loss of fruitwood has occurred in the lower canopy of all three 2.2-m hedge treatments, especially in the Unpruned but good commercial production has been maintained at 2400 to 3000 kg/ha The size of almond kernels was not affected by training method. Trunk circumference was affected by treatment. Trees in Temporary Hedge plots grew sustantially larger after alternate tree removal than trees in all 2.2-m hedge treatments that were equal in size.
602 Sequencing and Characterizing Blueberry (Vaccinium section Cyanococcus) Dehydrins
Authors: Panta Ganesh R. , Rieger Mark W. , Rowland Lisa J.
Published: February 2019

The blueberry industry experiences significant losses every year due to environmental factors with a dehydrative component, such as drought and freezing stress. In a recent survey of blueberry research and extension scientists in the United States, lack of cold hardiness and susceptibility to spring frosts were identified as the most important genetic limitations of current cultivars. For these reasons, cloning and characterization of expression of dehydration-responsive genes (dehydrins) have been ongoing in our laboratory. To date, one full-length (2.0 kb bbdhn1 gene) and four partial-length dehydrin cDNAs have been cloned and sequenced. Very high homology at the DNA and protein levels were found among the blueberry dehydrin clones, particularly at the 3' ends. From DNA blots, it appears that blueberry dehydrins are encoded by about three genes with high homology to the full-length 2.0 kb bbdhn1 cDNA clone and a few other less related genes. The 2.0 kb bbdhn1 gene was mapped in a blueberry population segregating for cold hardiness and chilling requirement. Expression studies indicated that dehydrins are induced by cold and drought stress. In general, dehydrins were induced in all organs examined in response to cold stress, including floral buds, leaves, stems, and roots. Under drought conditions, dehydrins were induced primarily in stems and their levels declined in roots. Some of the induced dehydrins were the same for drought and cold stress, whereas others were unique to a given stress. Levels of dehydrin accumulation correlated positively with cold hardiness; however, levels of dehydrins did not correspond precisely to the degree of drought avoidance.
604 Interspecific Hybridization between Euvitis and Muscadinia Grape Species
Authors: Lu Jiang , Prins Bernard
Published: February 2019

The grape belongs to the genus Vitis L., which are divided into two subgenera, Euvitis Planch. and Muscadinia Planch. The Euvitis has 50 to 70 species, in which V. vinifera L. is a predominant species with hundreds of known commercial cultivars grown world wide. The Muscadinia (muscadine grapes) consists of only two to three species predominated by V. rotundifolia and only commercially cultivated in the southeastern United States. V. rotundifolia is known by its multiple resistance to almost all grape diseases and insects found on the Euvitis species, while the latter possesses good fruit characteristics that do not exist in muscadines. Attempts to produce rotundifolia-vinifera hybrids to combine good fruit quality and disease resistance of both into F1 hybrids have been made by grape breeders for many years. Limited success was reported when the V. vinifera was used as seed parents. This research extended the interspecific crosses beyond V. vinifera into other Euvitis species. Among the Euvitis species, A. aestivalis, V. cinerea, V. champinii, V. labrusca, V. monticola, V. nesbittiana, V. riparia, V. rupestris, V. thunbergii, V. quinguangularis, all with pistillate flowers, were used as female parents pollinated with V. rotundifolia pollen. Eight out of the 10 cross combinations except V. cinerea and V. thunbergii set fruits. However, most of the Euvitis-rotundifolia crosses had extremely low fruits set (<1% of pollinated flowers). The only exception was V. labrusca cv. Woodruff, which had very high percentage of fruit set (70%). Interestingly, the fruits of V. labrusca cv. Woodruff × rotundifolia were pathonocarpic that had only half size of regular fruits set from open pollination with pollen sources from other Euvitis species. In the reciprocal crosses, three pistillate V. rotundifolia cultivars, `Fry', `Higgins', `Jumbo', were used as female pollinated by pollen from Euvitis species. Limited fruit sets were found from the crosses of V. rotundifolia × V. shuttleworthii, V. cordifolia, V. rupestris, V. Piasezkii, V. quinquagularis. Results from this study indicated that hybridization between Euvitis and muscadinia species is indeed very difficult but it is possible, and some Euvitis species are cross more compatible with V. rotundifolia than the others.
606 In Vitro Propagation of Some Strawberry Cultivars in Response to Kind and Concentration of Some Cytokinin Compounds
Authors: Aboul-Nasr M.H. , Elagamy S.Z. , Kassim A.M.
Published: February 2019

Three strawberry cultivars were used in this study. Runners from the three cultivars were grown on Murashige and Skoog medium supplemented with benzylaminpurine or kinetin at four concentrations (2, 1, 0.5, and 0.25 mg·L-1 in addition to the control treatment). The use of cytokinin, regardless of type and concentration, promoted the explant proliferation, shoot height, number of leaves, and plantlet fresh weight. Callus formation was enhanced by BA application, especially with `Pajaro'. However, `Chandler' did not form at all using cytokinin. Produced plantlets had lower nutrient constituents (N, P, K, Ca, and Na) when grown on media containing cytokinin compared to the control. Based on these results, cytokinin is recommended to get more shoots per explant. Furthermore, using the lowest concentration (0.25 mg·L-1) will produce height proliferation, greater shoot length, and more leaves.
611 High Temperature Acclimation and Catalase Stability in Pepper Leaves
Authors: Anderson Jeff
Published: February 2019

Activated forms of oxygen, including hydrogen peroxide, have been implicated in plant responses to stress. Environmental stresses may increase prooxidants, impair defense systems, or both. Stress acclimation may involve changes in capacity or stability of activated oxygen defenses. Catalases and peroxidases are the primary enzymatic detoxifiers of hydrogen peroxide in most plant tissues. Pepper leaf disks treated with hydrogen peroxide solutions from 0 to 100 mM showed increased electrolyte leakage and ethylene and methanol evolution with increasing concentration, but changes were slight compared to freeze-killed tissues. Data suggested that pepper leaves had considerable capacity to detoxify hydrogen peroxide. Cellular damage in heat-stressed tissues occurred over a similar temperature range that catalase activity declined. Leaf disks exposed to 24 to 59 °C for 15 min exhibited a sigmoidal electrolyte leakage response curve with an inflection at 51.5 °C. A similar plot of catalase activity vs. temperature exhibited an inflection point at 53.1 °C. Thermotolerance of plants exposed to the acclimating regime of 38 °C day/30 °C night increased from 50.7 to 53.9 °C based on electrolyte leakage. Catalase activity also showed an adaptive response with the inflection point increasing from 52.6 to 56.8 °C. It appears that catalase activity remains stable to a higher temperature in acclimated leaves, with similar activity in nonstressed control and acclimated plants.
613 Mitigation of Ethephon Injury to Tomato Plants by a Natural Lipid Lysophosphatidylethanolamine (LPE): Influence on the Activity of Phospholipase D (PLD)
Authors: Ozgen Mustafa , Palta Jiwan P. , Ryu Stephen B.
Published: February 2019

Ethephon [2-(chloroethyl) phoshonic acid] is used widely to maximize the yield of ripe tomato fruits. However, ethephon causes rapid and extensive defoliation, overripening, and promotes sunscald damage to the fruit. Recent studies from our laboratory have provided evidence that lysophosphatidylethanolamine (LPE) can reduce leaf senescence. We investigated the potential use of LPE to reduce damaging effect of ethephon on tomato foliage and influence on the activity of phospholipase D (PLD). Disruption of membrane integrity has been suggested as a primary cause of senescence in plants. PLD is known to be a key enzyme, which initiates the selective degradation of membrane phospholipids in senescing tissues. Two-month-old tomato plants (`Mountain Spring') grown in greenhouse condition were sprayed with water, 200 ppm LPE, and 1000 ppm ethephon. In addition, LPE spray prior to ethephon or mixture with ethephon were also tested. Leaves were sampled after 0, 2, 5, 24, 72, and 168 h of spray application, for PLD activity measurements. Spray of LPE prior to ethephon spray or inclusion of LPE in the ethephon spray reduced foliar injury by ethephon. Activity of soluble PLD was increased dramatically in leaves sprayed with ethephon initially and than dropped by 7 days. We also found that LPE-treated leaves had lower PLD activity than the ethephon-treated leaves. Plants treated with LPE-ethephon mixture also showed significantly lower PLD activity. These results suggest that LPE treatments mitigate ethephon injury to tomato plants. Furthermore, it appears that this mitigation involves modulation of the activity of PLD.
616 Effect of Temperature on Flower Size of Campanula carpatica `Blue Clips' and `Birch Hybrid'
Authors: Niu Genhua , Heins Royal D. , Cameron Arthur C. , Carlson William H.
Published: February 2019

Flower size generally decreases as temperature increases. The objective of this research was to investigate during development when flowers of Campanula carpatica Jacq. `Blue Clips' and `Birch Hybrid' are sensitive to temperature by conducting two temperature-transfer experiments. In the first experiment, plants were grown initially at 20 °C and then transferred at visible bud to 14, 17, 20, 23, or 26 °C until flower. In the second experiment, plants were transferred from 14 to 26 °C or from 26 to 14 °C at 1, 3, or 5 weeks (`Blue Clips') or at 1, 2, or 3 weeks (`Birch Hybrid') after flower induction. Temperature before visible bud had little effect on final flower size for both species. For example, flower diameter of `Blue Clips' was similar among plants grown at constant 14 °C or grown at 20 °C initially and then transferred at visible bud to 14 or 17 °C. Similarly, flower diameter of plants grown at constant 26 °C was similar to those grown at 20 °C initially and then transferred at visible bud to 26 °C. Flower diameter in these species is correlated with the temperature after VB in the 14 to 26 °C and decreases linearly as the temperature after VB increases.
617 Day and Night Temperatures, Daily Light Integral, and CO2 Enrichment Affect Growth and Flower Development of Campanula carpatica `Blue Clips'
Authors: Niu Genhua , Heins Royal D. , Cameron Arthur C. , Carlson William H.
Published: February 2019

Campanula carpatica Jacq. `Blue Clips' plants were grown in a greenhouse under ambient (400 μmol·mol-1) and enriched (600 μmol·mol-1) CO2 concentrations, three daily light integrals (DLI; 4.2, 10.8, and 15.8 mol/m per day), and nine combinations of day and night temperatures created by moving plants every 12 h among three temperatures (15, 20, and 25 °C). Time to flower decreased as plant average daily temperature (ADT) increased. Flower diameter decreased linearly as ADT increased in the 15 to 25 °C range and was not related to the difference between day and night temperatures (DIF). Increasing DLI from 4.2 to 10.8 mol/m per day also increased flower diameter by 3 to 4 mm regardless of temperature, but no difference was observed between 10.8 and 15.8 mol/m per day. Carbon dioxide enrichment increased flower diameter by 2 to 3 mm. Number of flower buds and dry mass at high and medium DLI decreased as plant ADT increased. Plant height increased as DIF increased from ñ6 to 12 °C. Number of flower buds and dry mass were correlated closely with the ratio of DLI to daily thermal time using a base temperature of 0 °C.
618 Effect of Preplant Hot-water and Fungicide Treatments on Tuber Development of Caladiums
Authors: Wilfret Gary J.
Published: February 2019

Intact tubers of Caladium cv. Florida Elise were soaked for 30 min in water at 24 or 50 °C in l998 and manually cut into cubes with 2-cm sides. Propagules were planted on 15-cm centers in raised sand beds covered with white plastic. Tubers were harvested in 6 months, air-dried, cleaned, weighed, and graded. Yield of No. 2 tubers (>1.9 <3.8 cm diam) was increased 31%, total tuber weight was 13% greater, and the production index was 13% larger due to hot-water treatment. No differences were determined for other tuber sizes. Tubers harvested from both treatments were soaked for 30 min in 1999 in water at 24 or 50 °C or in water at 24 or 50 °C that contained the fungicide Systec 85WDG [thiophanate methyl(dimethyl{(1,2-phenylene)-bis(iminocarbonothioyl)}bis{carbamate}] at 33.6 g/20 L. Tubers were cut and planted as in l998 and harvested in 2000. Tuber yields and production indices were greater in all hot-water treatments, but were not increased by fungicides alone. Yields from tubers that were not hot-water treated in l998 but were soaked in hot water in l999 were similar to those tubers that were hot-water-treated in both years. Fungicides did not have an additive effect when hot-water was used.
620 Enhancing Germination of Purple Coneflower (Echinacea angustifolia) Using Stratification, Salt Priming, and Biostimulants
Authors: Zinati Gladis M. , Bryan Herbert H. , Li Yuncong
Published: February 2019

Using herbs for medicinal purposes, ornamentals, and landscape plantings has increased significantly. Propagating from seeds is considered the most-efficient method of producing medicinal plants for commercial production. Among the herb seeds the purple coneflower (Echinacea angustifolia) was found difficult to germinate. Laboratory studies were conducted to: 1) determine optimum temperature from a temperature range 15 to 30 °C for seed germination; 2) determine effects of 5 10, 20, and 30 days of stratification at 5 and 10 °C in darkness on germination; and 3) determine effects of priming in the dark for 1, 3, 6, and 9 days with 0.1 M KNO3 and biostimulants at optimum temperature to enhance early emergence and final germination. Germination was enhanced from 45% in untreated seeds to 81% in seeds treated with either 50 ppm GA4/7 or 100 ppm ethephon at 24 °C. Final germination was 81% under daylight conditions when seeds were stratified in dark at 10 °C for 30 days over nonstratified seeds (13%). Priming seeds in 0.1 M KNO3 for 3 days significantly enhanced early germination to 70% with 100 and 150 ppm ethephon and final percent germination of 88% with either 100 ppm ethephon or 150 ppm GA4/7, while untreated control seeds resulted in 31% for same period of priming.
623 Lowbush Blueberry Response to Phosphorus Fertilizers with Different P: N Ratios
Authors: Smagula John M. , Litten Walter , Dunham Scott
Published: February 2019

In three commercial fields with a history of low leaf P concentrations, triple super phosphate (TSP) (1 P: 0 N), monoammonium phosphate (MAP) (2.1 P: 1 N), and diammonium phosphate (DAP) (1.11 P: 1 N) with P at 67.2 kg·ha-1 were compared to a control in a randomized complete-block design with 12 blocks. In 1995, all fertilizer treatments were comparable in raising soil P concentrations, but MAP and DAP resulted in higher P leaf concentrations compared to the control. DAP was more effective than MAP in raising N leaf concentrations. Leaf concentrations of Mg, B, and Cu were lowered by MAP and DAP but not TSP. Stem density, stem length, flower buds per stem, flower bud density, and yield were raised by DAP. The same treatments were applied in May 1997 and in May 1999 to the same plots in the same fields. In 1997, by the time of tip dieback in the prune year of that cycle, foliar concentration of P and N averaged higher than in the previous cycle, but still were not up to the standard for N. Fruit yield for the second cycle averaged substantially higher for the controls and for all three treatments, most dramatically for the DAP. In 1999, with only two fields available, response to treatments depended on soil N availability. At the field where leaf N was lower in control plots, MAP and DAP were more effective than TSP in raising leaf P.
626 Field Assessment of Combined Bud Damage on Floricanes of Red Raspberry Caused by Cold Injury, Clay Colored Weevil, and Spur Blight Disease
Authors: Chen Chuhe , Tanigoshi Lynell , Klauer Stephen F. , Menzies Geoff , Cameron J. Scott
Published: February 2019

A field experiment was conducted in Lynden, Wash., to assess the combined bud damage to raspberry caused by cold injury, clay colored weevil (CCW) and spur blight disease last year. The CCW treatments included 3 and 6 weeks of continuous feedings and a minimal feeding in a nearby planting with no CCW infestation. Two other sets of field experiments evaluated cold injury to raspberry alone. Cold injury caused significant bud damage and moderate yield losses last winter. The large compensatory ability of raspberry makes yield loss due to cold injury alone insignificant in most years. Cold injury reduced berry yield mainly through a drop in lateral number/cane due to bud damage and cane die back. The combined damage of cold injury with infestations of CCW and spur blight, to the buds and fruit yield were devastating, and 60% bud damage and 61% yield loss were recorded. The combined damage was well over the compensatory ability of raspberry, and resulted in not only lower lateral number/cane, but also lower fruit number/lateral and fruit weight. The bud damage by CCW in the spring left little time for the secondary laterals to initiate flowers. An integrated pest management system is highly recommended to avoid the cumulative damage to the buds and has special importance in areas, where cold injury occurs frequently. Bud damage counted as cold injury was higher in the control plots (18%) than in the weevil-infested plots (6% to 9%). This was likely due to undercount of some cold damaged buds in the infested plots, which also suffered CCW feeding. All plots had similar levels of spur blight bud infection numbering from low to mid-teens. Spur blight-infected buds are often capable of producing normal fruiting laterals.
630 Growth Regulators Affect the Morphology and Flowering of Argyranthemum, Calibrachoa, and Orthosiphon
Authors: Onken Hope K. , Starman Terri W.
Published: February 2019

Argyranthemum frutescens `Sugar Baby', Calibrachoa hybrid `Million Bells Cherry Pink', and Orthosiphon stamineus `Lavender' are three vegetatively propagated specialty annuals that are recent introductions into the floriculture industry. It is important to understand how the growth and development of these new crops is best controlled. Rooted cuttings of these three species where transplanted into 10-cm pots on 7 Oct. and the plant growth regulator treatments were applied on 19 Oct. 1999. Foliar spray treatments included ancymidol at 66 and 132, daminozide at 2500 and 5000, paclobutrazol at 20 and 40, ethephon at 500 and 1000, and uniconazole at 10 and 20 mg/L. Uniconazole medium drench treatment was applied at 1 and 2 mg/L. Control was a water foliar spray. At harvest, plant height, plant width, number of flowers, pedicle length, stem length, stem node number and internode length, and fresh and dry weights were measured. Uniconazole spray at 20 mg/L reduced plant height and width without affecting the fresh and dry weights of Argyranthemum. Flower number was increased and pedicel length was reduced. The overall plant height and width of Calibrachoa were not reduced with 20 mg /L uniconazole foliar spray, but plant form was improved by decreased internode elongation. Uniconazole foliar spray at 20 mg/L reduced Orthosiphon stem and internode length. Ethephon reduced plant height, plant width, and flower number of all species. Branching and days to flower were increased in Orthosiphon. In all species, daminozide and paclobutrazol were found to be ineffective, while ancymidol spray and uniconazole drench stunted and distorted growth.
632 GA4/7 and Light Level Affect Flowering and Plant Height of New Cultivars and Genetic Lines of Aquilegia ×hybrida Sims
Authors: Gianfagna T.J. , Merritt R.H. , Willmott J.D.
Published: February 2019

Aquilegia cultivars `Songbird Bluebird', `Songbird Robin', `Dove Improved', `Colorado Violet/White' and five cultivars from new experimental genetic lines (`Red and White', `Rose and White #1', `Rose and White #2', `Scarlet and Yellow' and `White') will flower without vernalization, but little is known of their response to light or plant growth regulators. Plants were started from seed on 5 Jan. 1999 and grown in either natural light or 33% shade, and treated with gibberellins (GA4/7) at the seven-leaf stage. Flowering time, number of flowers/plant, and plant height were evaluated through 31 May 1999. All five cultivars from the new genetic lines bloomed during the study. `White', grown in shade and treated with GA4/7, bloomed 2 weeks earlier (115 days) than untreated plants grown in natural light (130 days). `Songbird Robin', treated with GA4/7, bloomed in 146 days, and was the only other cultivar to bloom. Flower numbers were greater in natural light than in 33% shade. GA4/7 increased flowering for four of five cultivars, in the new genetic lines, grown in natural light. In shade, GA4/7 increased flowering for three of five cultivars. Height response to GA4/7 was significant in both natural light and 33% shade. Four of the five cultivars in the new genetic lines were taller when treated. All five of these cultivars were taller when grown in natural light verses 33% shade. `White' and both `Rose and White' cultivars were consistently taller, bloomed earlier and were more floriferous when treated with GA4/7.
634 Effects of Light Sources for Light Period Extension on Growth and Fowering in Statice
Authors: Yoo Dong-Lim , Lee Seung-Woo
Published: February 2019

This experiment was conducted to investigate the effects of artificial light sources for light period extension on growth and flowering of statice `Sophia' and `Early Blue'. The seeds were sown on 10 June in a plug tray with 128 plugs. The seedlings were grown at the highland (800 m above sea level) for 50 days, and transplanted on 30 July in 20-cm-diameter plastic pots. High-pressure sodium lamps (HPS) (220V, 400W), incandescent lamps (Il) (220V, 200W), and fluorescent lamps (Fl) (220V, 40W) for day length extension (16-h photoperiod) as compared with short day (8-h photoperiod) were tested. HPS gave the greatest photosynthetically active radiation (PAR), but Fl did the smallest. HPS or Fl as compared with Il showed high ratio of red/far-red light. The leaves of plant grown under HPS were effective for light absorbance and chlorophyll contents. HPS promoted photosynthesis as much as light period extension, while more respiration than photosynthesis occurred under Fl affected by low PAR. Long day condition as light period extension hastened flowering of statice, and HPS or Il were more effective than Fl on flowering among artificial light sources tested. The light compensation and saturation points of statice were 50 and 500 μmol·m–2·s–1, respectively. Photosynthesis hastened at high temperature, but amount of photosynthesis at vegetative stage showed much higher than flowering stage under the condition below 20 °C These results indicated that day length extension with HPS increased productivity and quality for cut flower of statice at the highland in Korea.
637 Selecting Rhizoma Peanuts (Arachis sp.) for Living Mulch in Vegetable Production in Florida
Authors: Bryan H.H. , Abdul-Baki A.A. , Carrera L. , Zinati G. , Klassen W.
Published: February 2019

Ground covers in orchards and living mulches in vegetable fields can be effective in reducing weed control costs and loss of water and nutrients from the soil, fixing N, and adding organic matter to the soil. Several accessions of rhizoma (perennial) peanut were evaluated in 1999, 30 months after planting, at the farm of the Tropical Research and Education Center, Univ. of Florida, Homestead, in gravelly, calcareous soil with a pH of 7.5. Evaluation criteria included adaptability (plant vigor, rhizome growth, and biomass yield), weed suppression, N-fixation, nutrient content, leaf density, and Fe chlorosis. Accessions that survived exhibited major differences in the evaluation criteria. Accessions No. 6968 and 4222 (recently named `Amarillo') showed promising potential for use as ground cover and a living mulch in vegetable fields in southern Florida.
642 Three-year Effects of Nitrogen Sources on Plant Component and Yields of Tomato
Authors: Whitehead Wayne F. , Singh Bharat P.
Published: February 2019

This study was conducted over 3 years for the purpose of determining how tomato yield, fruit number, and vegetative dry matter are affected by winter cover crop and recommended fertilizer N rates. The following winter-spring fertility treatments were applied using randomized complete-block design with four replications: 1) 0 N winter–0 N spring, 2) 0 N winter–90 kg N/ha spring, 3) 0 N winter–180 kg N/ha spring, 4) 0 N winter+abruzi rye–0 N spring, 5) 0 N winter+hairy vetch–0 N spring, and 6) 0 N winter+crimson clover–0 N spring. In Spring of 1996, 1997, and 1999 `Mountain Pride' tomatoes were transplanted in all plots. Total yield was compiled over 6 weeks, while seasonal fruit number and plant dry matter were measured at final harvest. In 1999, highest plant dry matter (350.5 g/plant) was produced by vetch and highest fruit number (36/plant) by 180 kg N/ha. Total yield were highest (85.8 Mg/ha) at 90 kg N/ha in 1996 and lowest (35.3 Mg/ha) for control during 1997. Organic nitrogen from hairy vetch and crimson clover affected plant dry weight, tomato number and yield comparable to those receiving synthetic N. Results over three years for this study indicate that legume cover crops can be an effective N fertilizer in supporting plant dry matter, fruit number and fruit yield of tomato.
644 Optimum Irrigation and Fertilization Regimes for Ivy Geranium (Pelargonium peltatum)
Authors: Jonas Valerie M. , Williams Kimberly A.
Published: February 2019

A series of experiments were conducted to determine the ranges of irrigation frequency and N and P fertilization regimes that produce ivy geranium (Pelargonium peltatum L.) plants of optimum commercial quality. Two cultivars, `Sybil Holmes' and `Amethyst', were grown. Data collected included fresh and dry weights, ratings, leaf area, height, width, ratings, and nutrient tissue content. Individual pots were weighed daily and irrigated when weight of pots dropped by 15%, 30%, 45%, or 60% of container capacity (CC). Leaf water potential was measured using a pressure chamber. At both mid and end of crop, plants irrigated when pot weight dropped by 30% of CC were under least water stress (e.g., water potential of –7.0 to –4.7 MPa). Irrigation frequencies at 15%, 45%, or 60% of CC had similar water potentials (e.g., –9.9 to –9.1 MPa). At 15%, a plausible explanation of the stress is that oxygen was limiting in the root zone due to water-logging; at 45% and 60%, water was the limiting factor. Single factor experiments with N at five concentrations ranging from 2 to 32 mm and P at five concentrations ranging from 0.08 to 2.56 mm were conducted. Quadratic equations were fit to curves of growth responses plotted against concentration of N or P applied. As an example of results, N fertilizer rates of 16 and 32 mm for `Amethyst' resulted in similar, commercially acceptable dry weights (37g), but different N tissue concentrations of 3.4% and 3.9% respectively. For `Sybil Holmes', N fertilizer rates of 10 and 26 mm resulted in similar dry weights (21g) but different tissue concentrations of 2.8% and 3.4%, respectively.
646 Comparison of Ca and B Deficiency Effects on Growth and Development of Bedding Plants
Authors: Pitchay Dharmalingam S. , Gibson James L. , Campbell C. Ray , Nelson Paul V. , Whipker Brian E.
Published: February 2019

The margin of error in pinpointing the difference in deficiency symptoms between calcium and boron is high. Several experiments were conducted in the greenhouse to induce as well as to differentiate the exact foliar and root symptoms of Ca and B. The experiments were conducted with modified Hoagland nutrient solutions. The treatments were with or without Ca or B salts for inducing total deficiency symptoms. Symptoms were expressed on the upper part including the growing point of the plant. In absence of Ca, marigold and zinnia plant heights were reduced by 58% and 37%, respectively, from the control. However, the reduction in height was only in the 27% and 25% range for B deficiency. Ca deficiency was noted as a blackened region on the leaf blade (early stage symptoms) which progressed into necrotic spots on the newly formed leaves. Severe necrosis, was observed on the growing point with advanced Ca deficiency. B deficiency results in a leathery and gray color in zinnia, needle like and narrow leaflets in marigold. The leaf blades were brittle in all B deficient species. B deficient plants roots were stiff and leathery and lateral roots possessed black nodule like endings at the tips. The Ca deficient roots expressed less side branching and at the advanced stage the roots were shorter and fewer with severe necrotic symptoms. The above initial and advanced deficiency symptoms appeared earlier in treatments without Ca than B. Images of Ca and B deficiency symptoms, as well as tissue concentration values will be presented.
647 Effects of Nitrogen Application Rates on Leachate Nitrogen Concentrations and Leatherleaf Fern Establishment
Authors: Stamps Robert H.
Published: February 2019

One of the most difficult times to balance crop nitrogen (N) requirements with concerns about nitrate-N leaching occurs during crop establishment, when root systems are poorly developed and not widely distributed in the growing medium. This dilemma can be exacerbated when producing a slow-growing plant such as leatherleaf fern (Rumohra adiantiformis [Forst.] Ching) on sandy soils in shadehouses in areas with significant rainfall. Rhizomes were planted in 36 drainage lysimeters containing Tavares fine sand located in a shadehouse. Nitrogen fertilizer was applied at nine rates using liquid and/or controlled-release fertilizer. Nitrogen application rates were varied as the rhizomes became established and spread into unplanted areas of the lysimeters. Irrigation and rainfall were monitored and the amount of water not lost to evapotranspiration was determined. Nitrogen (ammoniacal, nitrate/nitrite, total Kjeldahl) concentrations in leachate collected below the rootzone were determined. Stipe sap nitrate and frond total Kjeldahl nitrogen (TKN) were determined to try to develop a production monitoring technique. Initially, only leachate samples from controlled-release fertilizer plots treated at 21 and 42 kg of N/ha per year and liquid fertilizer at 28 kg of N/ha per year were consistently below the maximum contamination level (MCL) of 10 mg·L–1. As the fern became established, leachate nitrate/nitrite-N concentrations from higher N application rate treatments also remained below the MCL. Leachate N concentrations decreased as rainfall increased. Fern growth increased with increasing N application rate. Stipe sap nitrate-N and frond TKN concentrations were not well-correlated during establishment.
648 Assessment of Nitrogen, Phosphorus, Potassium, and Sulfur Pre-plant Nutrients on Plug Seedling Growth
Authors: Huang Jin-Sheng , Nelson Paul V.
Published: February 2019

Salinity guidelines for seed germination substrates are extremely low and difficult to attain given the salinity contributions of components such as peatmoss, vermiculite, limestone, wetting agent, and nutrients. This study was conducted to determine the value of N, P, K, and S as pre-plant nutrients with the anticipation that some could be eliminated. Seed were sown in two similar experiments on 23 Mar. and 6 June 1995 in 288-cell plug trays containing a substrate of 3 sphagnum peat: 1 perlite (v/v) amended with 6 g dolomitic limestone and 1.5 g Esmigran micronutrient mix per liter. Test plants included impatiens `Accent Rose' (Impatiens wallerana L.) and gomphrena `Buddy' (Gomphrena globosa. L.) Six preplant treatments including none, all, or all minus one of the nutrients N, P, K, and S were applied, each at a rate of 100 mg·L–1, substrate, in a randomized complete-block design with three blocks. Post-plant fertilization with 13–0.9–10.8 at 50 mg N/L began 1 week after sowing and was increased to 100 mg N/L when the fourth true leaf appeared. Omission of pre-plant K and S did not result in any reduction in final plant size in impatiens and only a minor reduction in one of the two gomphrena crops. Omission of N and P consistently reduced final size of plants by a commercially significant amount. While K and S are not necessary, N and P should be considered in a pre-plant fertilizer for these crops. In each situation where shoot size was smaller the root/shoot ratio was unchanged.
651 Educating the Public about the Design and Implementation of Sustainable Landscapes for Low-income Communities
Authors: Holcombe Veronda B. , Haque Mary T.
Published: February 2019

The concept of designing and implementing sustainable landscapes for low-income communities grew from collaboration between several community partners and Clemson Univ. It was our desire to research, plan, design, and implement sustainable landscapes for Habitat for Humanity homes. The primary goal of designing for these low-income homes was to design for sustainability. We wanted our plans to promote energy efficiency, water conservation, and low maintenance costs. These implemented principals would help the homeowner drastically cut living costs. The design and implementation of wildlife habitats was also encouraged to promote knowledge and research on environmental issues. In the beginning of our design phase we interviewed our client about her user needs/desires and later presented her with the design. This began the exhibition and education phase of the project. By exhibiting the project we hoped to education the homeowner about the sustainability issues that are pertinent to her case. Our biggest educational outreach program took place during homecoming at Clemson Univ. Partnering with other student organizations and using donated plant material from a local nursery, we constructed gardens and “planted” trees around a Habitat for Humanity house that is built each year during homecoming and later moved by trailer to its final site. We also displayed our designs inside the house and created pamphlets and brochures for visitors to pick up detailing such topics as Butterfly Gardening. Spurred on by the success of this project a web page detailing our community and organizational involvement was created. Our projects have been covered in many newspaper articles, cable TV, and in a video on service learning being produced for national distribution. As a student it has given me and my other student colleagues an opportunity to engage in and acquire valuable hands-on experience in horticulture and environmental education/stewardship all the while providing a much needed public outreach service that assists and partners with community members in order to enhance their personal home environments.
656 Commercialized Biotechnology, Food for Thought
Authors: Baldwin E.A.
Published: February 2019

The promise of biotechnology has been slow to be realized, but some commercialized products are finding their way to supermarket shelves. Nevertheless, the future potential remains in the realm of speculation and may be on the verge of delivering some incredible benefits. Since the world population growth is predicted to double in the next 50 years, primarily in developing nations, food resources will become critical. In view of this prediction, we may need every trick in the book to feed the masses, which means either more land (wetlands, forests, and rain forests) will fall to the plow or there will need to be an increase in yields. Concurrently, a decrease in postharvest losses would also be crucial. Various authorities have estimated that 25% to 80% of harvested fruits and vegetables are lost due to damage and spoilage. Early biotech successes were developing plants with enhanced insect resistance (cotton, corn, and potato) and virus resistance (squash and papaya) and improved herbicide tolerance (cotton, soybean, and corn). The only commercialized transgenic fruit engineered for improved postharvest quality so far is the tomato. Future goals for biotechnology include increasing yield, extending shelf life, improving nutritional and flavor quality, and producing specialty proteins or other compounds. Genetically engineered food, however, has met rancorous resistance in Europe, New Zealand, and elsewhere; although, it is somewhat tolerated in the U.S. The U.S., Canada, and Japan lead the world in biotech acreage, with biotechnology accounting for 40% of cotton, 39% of soybeans, and 20% of corn acreage in the U.S. and 73 million acres worldwide.