bluuebunny/crossref_metadata_2025 huggingface dataset:
Ebb and Flow Production of Petunias and Begonias as Affected by Fertilizers with Different Phosphorus Content
Authors: James Erin , van Iersel Marc
Published: February 2019

Water conservation is increasingly important for growers in the United States, but there is little information on the use of alternative irrigation systems, such as ebb and flow, for the production of bedding plants. The objective of this study was to quantify the growth of Petunia ×hybrida Hort. Vilm.-Andr. `Blue Frost' and Begonia ×semperflorens-cultorum Hort. `Ambassador Scarlet' grown in an ebb and flow system in three soilless media and fertilized with P at 0, 50, or 100 mg·L-1 in the fertigation solution. After 5 weeks, plants grown with 50 or 100 mg·L-1 P had greater dry weight, height, and width than plants grown with 0 mg·L-1 P. Begonias grown with 50 or 100 mg·L-1 P had 38% more flowers than did those grown without P. Petunias flowered 4 to 7 days earlier when no P included in the fertilizer. Growing media had little effect on the plants. Begonias grown in Metro-Mix 220 had more inflorescences than those grown in Metro-Mix 366Coir. Changes in electrical conductivity (EC) and pH of all three media were similar over the course of the experiment. The EC dropped during the third and fourth week and rose again in the fifth week. The pH of the leachate from all three media dropped by an average of 1 unit during the experiment. The results indicate that petunias and begonias may be grown successfully with ebb and flow irrigation, using a variety of fertilizers and growing media. However, P must be included in the fertigation solution for optimal plant quality.
Testing the Effects of Moisture on Seedcoat Color of Pinto Dry Beans
Authors: Ergun Muharrem , Paparozzi Ellen T. , Coyne Dermot P. , Smith Durward , Kachman Stephen , Nuland David S.
Published: February 2019

Seedcoat color is an important trait, as it affects marketing and consumer acceptance of pinto beans (Phaseolus vulgaris L.). Pinto breeding line NE 94-4 showed seedcoat yellowing in on-farm field trials in Nebraska in 1996 and 1997. Hail, sprinkler irrigation, and fall rainfall appeared to be involved in increasing seedcoat yellowing, based on analysis of field and weather data of on-farm trial sites. The objective of this study was to determine the effect of moisture on seedcoat yellowing of pinto line NE 94-4 (susceptible) and pinto `UI-114' (highly resistant). Two greenhouse experiments were conducted involving misting of bean plants near maturity and injecting water into maturing bean pods. Another experiment evaluated the response of seeds of these two bean entries to moisture by placing them on moist filter paper in petri dishes in the laboratory. Results showed that both genotype and moisture content are involved in seedcoat yellowing. This simple, cheap, and effective filter paper test was then used to evaluate seedcoat yellowing of nine pinto genotypes in response to moisture. Pinto NE 94-4 and `Kodiak' showed the greatest change, while `Bill Z' showed the least change, in seedcoat color.
Heat Requirement for Blooming and Leafing in Peach
Authors: Citadin I. , Raseira M.C.B. , Herter F.G. , da Silva J. Baptista
Published: February 2019

Differences in heat requirements for blooming and leafing were investigated in peach [Prunus persica (L.) Batsch] using artificially chilled excised shoots and potted trees. `Della Nona' and `BR-1' have high heat requirements; `Planalto', `Sunlite', and `Eldorado' are intermediate; and `Precocinho' and `Riograndense' have low heat requirements. Prolonged chilling enhanced leafing more than blooming. Flower and vegetative buds have different heat requirements during ecodormancy.
In Vitro Colonization of Micropropagated Pieris floribunda by Ericoid Mycorrhizae. I. Establishment of Mycorrhizae on Microshoots
Authors: Starrett Mark C. , Blazich Frank A. , Shafer Steven R. , Grand Larry F.
Published: February 2019

Selected isolates of Hymenoscyphus ericae (Read) Korf and Kernan, Oidiodendron griseum Robak, O. maius Barron, and a second O. Robak species were evaluated as inocula for in vitro establishment of micropropagated plantlets of Pieris floribunda (Pursh ex Sims) Benth. and Hook. Severity of shoot necrosis on microshoots differed for each isolate of Oidiodendron. Inoculation of micropropagated plantlets with isolates of H. ericae benefited initial shoot and root development on agar-solidified Woody Plant Medium (WPM) supplemented with sucrose and covered by a layer of autoclaved 1 peat: 1 vermiculite (v/v). Inoculation of microshoots with H. ericae or isolates of Oidiodendron did not stimulate production of adventitious roots.
Vernalization in a Greenhouse Promotes and Synchronizes Flowering of Osteospermum ecklonis Norl.
Authors: Suzuki Ayumi , Metzger James D.
Published: February 2019

The effect of cool temperature treatments on flowering of Osteospermum ecklonis Norl. cv. Nairobi was evaluated. Plants vernalized at temperatures from 4 to 15 °C for 4 to 6 weeks exhibited increased flower numbers, more synchronized flower development among individual plants, and reduced forcing times. Part of the increased flower number observed in the vernalized plants could be attributed to a small increase in branch numbers from 2 to 3. However, a longer period of vernalization slowed flower development, and therefore increased overall production times. Vernalization also reduced stem growth, primarily through a reduction in the number of nodes produced by each branch.
Temperature, But Not Ethephon, Influences Fruit pH of Processing Tomato
Authors: Renquist A. Richard , English Jacinda M. , Reid Jeff B.
Published: February 2019

The pH of processing tomato at harvest is a key quality criterion and is critical for safe product storage. Maximum allowable fruit homogenate pH is often 4.5. Our objective was to quantify the influence of air temperature on pH, including any interaction with either fruit age or use of ethephon. Three planting dates were imposed as main treatments and ethephon as a subtreatment in a field trial, and each planting was harvested on four dates. Fruits were harvested from trusses tagged to identify three fruit age groups in sub-subplots. Temperature exerted primary control of tomato pH. The relationship of bulk fruit pH to thermal time was curvilinear (pH was always <4.55); however, when pH was related to thermal time from anthesis, a linear relationship resulted. The oldest fruit had a much higher pH (>4.5) than younger ones (mean pH for all dates = 4.3). Ethephon did not alter these temperature/pH relationships.
Physiological Responses to Heat Stress Alone or in Combination with Drought: A Comparison between Tall Fescue and Perennial Ryegrass
Authors: Jiang Yiwei , Huang Bingru
Published: February 2019

Heat and drought are two major factors limiting growth of cool-season grasses during summer. The objective of this study was to compare the effects of heat stress alone (H) or in combination with drought (H+D) on photosynthesis, water relations, and root growth of tall fescue (Festuca arundinacea L.) vs. perennial ryegrass (Lolium perenne L.). Grasses were exposed to H (35 °C day/30 °C night) or H+D (induced by withholding irrigation) in growth chambers for 35 days. Soil water content declined under H+D for both grasses but to a greater extent for fescue than for ryegrass. Declines in canopy net photosynthetic rate (Pn), leaf photochemical efficiency (Fv/Fm), and leaf relative water content (RWC) and the increase in electrolyte leakage (EL) were much more severe and occurred earlier for ryegrass than fescue subjected to both H and H+D and for both species than under H+D then H. Evapotranspiration (ET) rate increased to above the control level within 3 or 6 days of H and H+D for both species, but fescue had a higher ET rate than ryegrass at 3 and 6 days of H and 6 days of H+D. Root dry weight and viability in all soil layers decreased under H and H+D for both species. However, fescue had higher root dry weight and viability than ryegrass in the 20-40 cm layer under H and in both the 0-20 and 20-40 cm layers under H+D. The results indicated that maintenance of higher Pn, Fv/Fm, ET, RWC, and root growth and lower EL would help cool-season turfgrass survive summer stress, and that their characteristics could be used for selecting stress tolerant species or cultivars.
Canopy Architecture and Cuvette Flow Patterns Influence Whole-canopy Net CO2 Exchange and Temperature in Sweet Cherry
Authors: Whiting Matthew D. , Lang Gregory A.
Published: February 2019

To initiate photosynthetic studies of sweet cherry (Prunus avium L.) canopy architectures and cropping management under high light and temperature conditions (Yakima Valley, Wash.), we developed a whole-canopy research cuvette system with a variable airflow plenum that allowed different patterns of air delivery (in concentric circles around the trunk) into the cuvette. Air and leaf temperatures (Tair and Tleaf, respectively) were determined at four horizontal planes and four directional quadrants inside cuvette-enclosed canopies trained to a multiple leader/open-bush or a multiple leader/trellised palmette architecture. Air flow rate, air delivery pattern, and canopy architecture each influenced the whole-canopy temperature profile and net CO2 exchange rate (NCER) estimates based on CO2 differentials (inlet-outlet). In general, Tair and Tleaf were warmer (≈0 to 4 °C) in the palmette canopy and were negatively correlated with flow rate. The response of Tair and Tleaf to flow rate varied with canopy position and air delivery pattern. At a flow of 40 kL·min-1 (≈2 cuvette volume exchanges/min), mean Tair and Tleaf values were 2 to 3 °C warmer than ambient air temperature, and CO2 differentials were 15-20 μL·L-1. Tair and Tleaf were warmer than those in unenclosed canopies and increased with height in the canopy. Carbon differentials declined with increasing flow rate, and were greater in the palmette canopy and with a less dispersed (centralized) delivery. Dispersing inlet air delivery produced more consistent values of Tair and Tleaf in different canopy architectures. Such systematic factors must be taken into account when designing studies to compare the effects of tree architecture on whole-canopy photosynthesis.
Postharvest Irradiation Enhances Anthocyanin Synthesis in Apples But Not in Pears
Authors: Marais Evelyn , Jacobs Gerard , Holcroft Deirdre M.
Published: February 2019

`Cripps' Pink' apples (Malus ×domestica Borkh.) subjected to 72 hours of postharvest irradiation developed a better red blush with high pressure sodium (HPS) (hue angle 56.5°) than with UV-B plus incandescent (UVB+I) lamps (hue angle 70.7°). Only HPS lamps were used in subsequent experiments. The increase in red color (hue angle decrease of 14.9°) in `Braeburn' apples held at -0.5 °C for 8 weeks prior to treatment was smaller than in fruit stored for 4 weeks (hue angle decrease of 23°). No increase in color or anthocyanin concentration was observed in `Forelle' pears (Pyrus communis L.) that were similarly treated. `Forelle' pears were harvested with or without attached stem and leaves to determine whether precursor availability restricted postharvest color development. Fruit were irradiated with HPS at 20/20 °C and 20/6 °C (day/night) for 168 hours. The absence of leaves hastened the decrease in hue angle, but this was due to yellowing and not to development of red blush. Since `Forelle' pears showed no response to light after harvest, two fully red cultivars, Bon Rouge and Red Anjou, were irradiated with HPS lamps for 72 hours. Hue angle was not affected by irradiation. Thus, anthocyanin synthesis was stimulated by postharvest irradiation with HPS lights in apples, but not in pears.
'Norland' Tuber Yields Are Not Affected by Salinity Treatment of Parent Plants
Authors: Zhang Y. , Abdulnour J.E. , Donnelly D.J. , Barthakur N.N.
Published: February 2019

Micropropagation and minituber production technology may enable the establishment of potato (Solanum tuberosum L.) seed tuber certification programs in arid and semiarid regions of the world and reduce dependency on expensive seed tuber imports. Therefore, we investigated possible carry-over effects of moderate salt stress on the following production cycle. The yields of seed tuber- and microtuber-derived plants of potato, cv. Norland, grown in both nonsaline and saline (NaCl) growing conditions (pretreatment), were evaluated under nonsaline or saline irrigation (0 or 60 mm NaCl) in a greenhouse trial. Pretreatment had no effect on yield; there was no apparent residual carry-over effect of salt stress of parent plants on tuber yield of seed tuber- or microtuber-derived plants. Irrigation with a 60 mm NaCl solution depressed total tuber fresh weight in both seed tuber-(43%) and microtuber-derived plants (75%), but total tuber number was increased (77% and 663%, respectively). This increase in tuber numbers has potential value in the minituber production industry.
Trinexapac-ethyl Increases Kentucky Bluegrass Leaf Cell Density and Chlorophyll Concentration
Authors: Ervin E.H. , Koski A.J.
Published: February 2019

The effects of trinexapac-ethyl (TE) on the anatomical and biochemical composition of turfgrasses and their implications for its field use are poorly understood. Two greenhouse experiments were conducted to determine if application of TE increased Kentucky bluegrass (Poa pratensis L.) leaf blade cell density, chlorophyll concentration, or structural carbohydrate content. Kentucky bluegrass (KB) sod was harvested from the field, established in greenhouse pots, and sprayed with 0.27 kg·ha-1 a.i. TE. Leaf blade samples were collected 4 weeks after treatment (WAT), fixed in glutaraldehyde, and embedded in Spurr resin. Photomicrographs of longitudinal leaf blade sections were used to determine cell density, cell length, and cell width. Chlorophyll and structural carbohydrate contents were determined at 2 and 4 WAT. Treatment with TE increased cell density and chlorophyll-b concentration, while reducing cell length, but structural carbohydrate content was unaffected. Chemical name used: 4-cyclopropyl-α-hydroxy-methylene-3,5-dioxo-cyclohexanecarboxylic acid ethyl ester (trinexapac-ethyl).
The Role of Leaves and Carbohydrates in Flowering of Protea cv. Lady Di
Authors: Gerber Audrey I. , Theron Karen I. , Jacobs Gerard
Published: February 2019

Inflorescence initiation in Protea cv. Lady Di (P. magnifica Link × P. compacta R. Br.) occurs predominantly on the spring growth flush when it is subtended by one or more previous growth flushes. Mature, over-wintering leaves are essential for induction of flowering in `Lady Di', and are also crucial to the early stages of inflorescence initiation and differentiation. Defoliation before elongation of the spring growth flush was complete prevented flowering, and shoots either remained vegetative or produced inflorescences that aborted. Levels of carbohydrates in the stem and leaves of overwintering shoots were low, and early growth and development of both the spring flush and inflorescence were, therefore, supported by current photosynthates from the mature leaves on the overwintering shoot. Likewise, reserve carbohydrates available in the flowering shoot were insufficient to account for the rapid increase in dry weight during the major portion of growth of the spring flush and inflorescence. This increase occurred after elongation of the spring flush was complete and was supported by current photosynthates from the leaves of the spring flush. Defoliation treatments that did not prevent inflorescence initiation had no effect on inflorescence development or on flowering time.
Gibberellic Acid Slows Postharvest Degreening of 'Oroblanco' Citrus Fruits
Authors: Porat Ron , Feng Xuqiao , Huberman Moshe , Galili David , Goren Raphael , Goldschmidt Eliezer E.
Published: February 2019

'Oroblanco' is an early-maturing pummelo-grapefruit hybrid (Citrus grandis Osbeck × C. paradisi Macf.). The fruit are usually picked and marketed while the peel color is still green; however, in some cases they can lose this green color during postharvest shipping and storage, which diminishes their commercial value. The effects of storage temperatures, gibberellic acid (GA), ethylene, and 1-methylcyclopropene (1-MCP) on the degreening of 'Oroblanco' fruit were examined. Storage temperature was critical for retaining fruit color: at 2 °C the fruit remained green for a period up to 5 weeks, whereas at storage temperatures of 6, 12, and 20 °C there was a progressive increase in the rate of degreening. Applications of GA, either as preharvest sprays or as postharvest dip treatments, effectively retained the green fruit color. Ethylene exposures up to 100 μL·L-1 for 3 days had only a slight effect on fruit degreening, and 1-MCP treatments up to 200 nL·L-1 for 16 hours had no effect at all. The slight influence of ethylene and the ineffectiveness of 1-MCP on fruit color change can not be attributed to difficulties in their application, since in the same experiments ethylene markedly induced peduncle abscission, and 1-MCP effectively inhibited this ethylene effect. Accordingly, ethylene had only a relatively small effect on the induction of chlorophyllase enzyme activity in green 'Oroblanco' peel tissue.
Density Separation, Storage, Shelf Life, and Sensory Evaluation of 'Fry' Muscadine Grapes
Authors: Walker Teresa L. , Morris Justin R. , Threlfall Renee T. , Main Gary L. , Lamikanra Olusola , Leong Stephen
Published: February 2019

Muscadine grapes (Vitis rotundifolia Michx.), native to the southeastern United States, have a distinct flavor, and grocers are interested in marketing them as table grapes. Two studies using 'Fry' muscadines were conducted to assist the muscadine industry in providing quality table grapes. Study 1 (1998 and 1999) evaluated density sorting and relationships between maturity, color, soluble solids, firmness, shelf life, and sensory evaluation of grapes. Study 2 (1998) determined the effect of storage on quality attributes of different maturities of grapes and evaluated use of polyethylene bags to extend their storage. Density separation successfully sorted grapes by maturity. Muscadine berry color may allow for visual or electronic sorting to eliminate immature fruit. Sensory panelists could distinguish differences in maturities for all sensory attributes. In 1999 maturities 3 and 4 (≈24-33 soluble solids: acid ratio) were preferred overall by panelists. As maturity increased, soluble solids and pH increased, and acidity decreased. Firmness decreased as maturity and storage at 2 °C increased. Percent decay increased with maturity and storage time. Grapes stored in polyethylene bags had reduced decay. A chart developed from the 1999 data related berry color to soluble solids: acid ratio, soluble solids, tartaric acid, and pH. Data from these studies can be used by industry to establish harvest parameters and enhance marketability of 'Fry' muscadine grapes.
Choice of Adjuvant with Halosulfuron Affects Purple Nutsedge Control and Nursery Crop Tolerance
Authors: McDaniel Gary L. , Klingeman William E. , Witte Willard T. , Flanagan Phillip C.
Published: February 2019

One-half (18 g·ha-1 a.i.) and three-fourths (27 g·ha-1 a.i.) rates of halosulfuron (Manage®, MON 12051) were combined with adjuvants and evaluated for effectiveness in controlling purple nutsedge (Cyperus rotundus L.) and for phytotoxic responses exhibited by two kinds of container-grown ornamental plants. Adjuvants included X-77®, Scoil®, Sun-It II®, Action “99”®, and Agri-Dex®. By 8 weeks after treatment (WAT), halosulfuron combined with X-77®, Agri-Dex®, or Action “99”® at the lower halosulfuron rate provided <90% purple nutsedge suppression. In contrast, Sun-It II® provided 100% control when combined with the higher halosulfuron rate. Nutsedge control persisted into the following growing season and halosulfuron combined with either Scoil® or Sun-It II® provided >97% suppression of nutsedge tuber production. Growth of liriope [Liriope muscari (Decne.) Bailey `Big Blue'] was not inhibited by Scoil® or Sun-It II® adjuvants in combination with the low rate of halosulfuron. However, regardless of the rate of halosulfuron or adjuvant used, initial foliar chlorosis was observed in both daylily (Hemerocallis sp. L. `Stella d'Oro') and liriope. All liriope receiving halosulfuron with X-77®, Scoil®, or Sun-It II® adjuvants recovered normal foliage by 8 WAT. By contrast, at 8 WAT some daylily still maintained a degree of foliar discoloration. In addition to chlorosis, all treatments reduced flower number in daylilies. The number of flower scapes produced by liriope was not affected by halosulfuron when in combination with either Sun-It II® or Scoil®. The high rate of halosulfuron combined with X-77® or Action “99”® improved control of purple nutsedge. However, this rate inhibited growth of both species, daylily flower numbers, and scape numbers of liriope, regardless of adjuvant. Chemical names used: halosulfuron (Manage®, MON 12051, methyl 5-{[(4,6-dimethyl-2-pyrimidinyl) amino] carbonyl-aminosulfonyl}-3-chloro-1-methyl-1-H-pyrozole-4-carboxylate); proprietary blends of 100% methylated seed oil (Scoil® and Sun-It II®); proprietary blend of 99% polyalkyleneoxide modified heptamethyl trisiloxane and nonionic surfactants (Action “99”®); alkylarylpolyoxyethylene, alkylpolyoxyethelene, fatty acids, glycols, dimethylpolysiloxane, and isopropanol (X-77®); proprietary blend of 83% paraffin-based petroleum oil, with 17% polyoxyethylate polyol fatty acid ester and polyol fatty ester as nonionic surfactants (Agri-Dex®)
Yield, Dry Matter Partitioning, and Storage Quality of Hardneck Garlic as Affected by Soil Amendments and Scape Removal
Authors: Rosen Carl J. , Tongn Cindy B.S.
Published: February 2019

Two on-farm field studies were conducted in 1996 and repeated in 1997 to determine the effects of soil amendments and scape (flower stalk) removal on yield, dry matter partitioning, and storage quality of hardneck garlic (Allium sativum L.). One study site was on a loamy sand soil with low organic matter and fertility and the other site was on a sandy loam soil with high organic matter and fertility. Soil amendment treatments tested at both sites were: 1) no amendment, 2) composted manure, and 3) inorganic fertilizer according to soil test recommendations. A fourth treatment, dried, composted turkey-manure-based fertilizer, was included at the low organic matter site. Scapes were removed at the curled stage from plants in half of the harvest rows. Scapes from the remainder of the harvest row plants were allowed to mature until harvest. In 1997, bulbs from each treatment were stored at 0 to 3 °C or 19 to 21 °C for 6 months. Soil amendment treatments had no effect on total garlic bulb yield, dry mass partitioning, or stored bulb weight loss at the sandy loam, high organic matter site. Manure compost, fertilizer, and composted turkey manure soil amendments reduced the yield of smaller bulbs compared with the control at the loamy sand, low organic matter site. The proportion of bulbs >5 cm was highest with the manure compost treatment. At the low organic matter site, scape removal resulted in a 15% increase in bulb yield and an increase in bulb size compared with leaving scapes on until harvest (P = 0.05). At the high organic matter site, scape removal increased bulb yield by 5% (P = 0.10). Scape removal increased dry matter partitioning to the bulbs, but had no effect on total (scape + shoot + bulb) aboveground dry matter production. The increase in bulb dry mass when scapes were removed was offset by an increase in scape dry mass when scapes were left on. Bulb weight loss in storage was less at 0 to 3 °C than 19 to 21 °C. Soil amendments only affected bulb storage quality at the loamy sand, low soil organic matter site. The effect of scape removal on bulb weight loss was nonsignificant at either location.
Developmental Transition Between Sucrose Uptake and Sucrose Efflux Systems in the Vacuole of Red Beet Hypocotyl Cells
Authors: Etxeberria Ed , Gonzalez Pedro
Published: February 2019

The mechanisms of sucrose uptake into the vacuole and sucrose efflux from the vacuole were studied using tonoplast vesicles from red beet at two distinct developmental stages. Vesicles from both developing and mobilizing hypocotyls (sucrose uptake and efflux, respectively) accumulated sucrose against a concentration gradient. However, higher rates and maximal levels of sucrose accumulation were obtained with tonoplast from developing hypocotyls. ATP-dependent sucrose efflux was more pronounced in vesicles from mobilizing hypocotyls. Despite the apparent overlapping, the data indicate that the physiological mechanisms for sucrose uptake and sucrose efflux are separated in time and governed by the developmental state of the cell. Chemical name used: adenosine 5′-triphosphate (ATP).
An Economic Analysis of Preharvest Fungicide Applications to Control Botrytis Fruit Rot in Annual Strawberries in Florida
Authors: Haydu John J. , Legard Daniel E.
Published: February 2019

The control of postharvest Botrytis fruit rot was evaluated during 1995-96, 1996-97, and 1997-98. Weekly applications of captan and thiram were examined at two or three different rates, respectively. Iprodione applications were combined with the captan and thiram treatments and applied alone for two peak bloom periods. Strawberry fruit were harvested and graded twice weekly for marketable yield and preharvest incidence of Botrytis fruit rot. For postharvest evaluations, fruit from four harvests were selected and stored at 4 °C, and Botrytis fruit rot incidence was recorded over 14 days of storage. Fungicide treatments reduced the incidence of preharvest Botrytis fruit rot and increased marketable yield. Marketable yield data were then used to extrapolate production into net economic returns per hectare. In 1995-96, net returns per hectare ranged from a low of $16,008 in the control treatment to a high of $20,728 for captan. In 1996-97, net returns ranged from a low of $3,655 per hectare for the control to a high of $17,985 for captan + iprodione. In 1997-98, net returns varied from -$641 per hectare for iprodione to a high of $24,215 for captan. Over the experiment's 3-year period, net returns averaged a low of $4,172 for iprodione alone to $19,074 for captan. The study concluded that, at roughly $1,000 per season, fungicide treatments represent a minor proportion of total costs, yet have large impacts on strawberry production profits.
An Economic Analysis of the Greenhouse, Nursery, and Sod Sector in the United States
Authors: Tavernier Edmund M. , Brumfield Robin G.
Published: February 2019

The greenhouse, nursery, and sod (GNS) sector in the United States accounted for $10 billion in gross sales or 5% of gross farm receipts, in 1998. Despite its significant economic contributions, the sector receives little attention from policymakers. Part of the problem lies in the absence of empirical economic analysis that addresses the impact of the sector on the U.S. economy. The absence of such analysis places the sector at a disadvantage when agricultural policies are designed to address agricultural imbalances, such as farm income problems, and hinders the ability of the sector to lobby for policies favorable to GNS producers. This study provides estimates of the economic impacts of the GNS sector on the U.S. economy and quantifies the linkages between the GNS sector and other economic sectors. The results show that the sector contributed over $26 billion and $17 billion in output and value added economic activity, respectively, and over 438,000 jobs.
Quantifying the Cooling Period for Flowering of 'Nellie White' Easter Lily
Authors: Tammen James F.
Published: February 2019

In the commercial development of an innovative process for the production of pathogen-indexed Easter lilies (Lilium longiflorum Thunb.) in less than a year, it became desirable to quantify the cooling period so that the time of flower induction/initiation could be determined. Based upon studies of forcing flowering plants from bulbs, I hypothesized that cooling could be quantified using the cool temperature unit (CTU), defined as 1 °C below 21 °C for 1 hour, and the warm temperature unit (WTU), defined as 1 °C above 21 °C for 1 hour. The purpose of these studies was to determine if the hypothesis was valid. With 'Nellie White' Easter lily, it was determined that cooling could be quantified as hypothesized. The minimum threshold number of CTU that would induce flowering in at least one plant of the test population after exposure to long days was between 1200 and 2400, whereas the threshold number of CTU that would induce flowering in 100% of the population was 3600. The optimum threshold, i.e., the number of CTU that would result in the best market quality, was estimated to be 4800. The studies demonstrate that market quality, pathogen-indexed flowering potted Easter lilies growing continuously from bulblets can be produced in about 1 year, and that the cooling required to sensitize the plants to long days, which is central to the success of the fast production process, is quantifiable.
Development, Detection, and Elimination of Verticillium dahliae in Mint Shoot Cultures
Authors: Wang Nan , Reed Barbara M.
Published: February 2019

Roots of greenhouse-grown mint plants and in-vitro-grown shoot cultures were inoculated with Verticillium dahliae Kleb. conidial suspensions to study wilt symptom development and detection and elimination of the fungus. There were significant differences in the symptom expression between control and infected shoot cultures at all conidia concentrations for the four mints tested. Disease-symptom ratings were proportional to the V. dahliae inoculum density. Infected shoot cultures were stunted when inoculated with ≥ 103 conidia/mL. Verticillium dahliae was re-isolated from infected shoot cultures at all levels of inoculum, but not from any control cultures. Verticillium infections were easily detected by plating mint stems on potato dextrose agar. Shoot tips (0.5 to 15 mm) from infected in-vitro- and greenhouse-grown plants were isolated and screened for fungus. The most effective shoot length for fungus elimination was 3-5 mm. Shoot tips isolated from in vitro spearmint cultivars infected at 102 and 103 conidia/mL were 100% Verticillium free, but only 42% of `Black Mitcham' and 54% of `Todd's Mitcham' peppermints were free of the disease. Shoot tips from infected greenhouse plants produced Verticillium-free cultures from 79% of `Black Mitcham' and 90% of `Todd's Mitcham' plants. These results indicate the utility of testing for Verticillium and the safety of micropropagated mint shoots for certified planting stock programs.
Nonconventional Additives Leave Onion Yield and Quality Unchanged
Authors: Feibert Erik B.G. , Shock Clinton C. , Saunders Lamont D.
Published: February 2019

Eleven treatments in 1999 and thirteen treatments in 2000 containing single or combined nonconventional additives from eight manufacturers were compared with an untreated check for their effect on onion (Alliumcepa L.) yield and quality, and for their economic efficiency. The nonconventional additives were tested at commercial rates using the methods of application provided by the manufacturers. The products were applied to soil, foliage, or both. The treatments, including the check, were incorporated into standard cultural practices for onions. All treatments (with exception of an organic fertilizer treatment), including the check, were fertilized based on soil tests. In both years, none of the products evaluated significantly increased onion yield or quality compared to the untreated check. The organic fertilizer treatment, tested in 1999 only, resulted in significantly lower onion yield and size compared to the check. At the application rates used in this study, most of the products supplied plant nutrients or humic acid in amounts insufficient to expect improvements in crop production.
Postharvest Quality of 'Bing' Cherries Following Preharvest Treatment with Hydrogen Cyanamide, Calcium Ammonium Nitrate, or Gibberellic Acid
Authors: Clayton Murray , Biasi William V. , Agar I. Tayfun , Southwick Stephen M. , Mitcham Elizabeth J.
Published: February 2019

During three consecutive years, 'Bing' sweet cherry (Prunus avium L.) trees were treated during dormancy with the dormancy-manipulating compounds, CH2N2 or CaNH4NO3, or were treated with the plant growth regulator GA3 at straw color development. Fruit of a range of maturities, based on skin color, were evaluated for quality following harvest and simulated transit and market storage conditions. At comparable maturities, CH2N2 and GA3 fruit were of similar firmness and were consistently firmer than CaNH4NO3-treated and untreated fruit across years, storage regimes, and maturities. CaNH4NO3 and untreated fruit were of similar firmness. CH2N2-treated cherries were larger than fruit of other treatments, but only marginally with respect to variation in fruit size between years. Contraction of fruit diameter occurred after 3 days storage, but ceased thereafter up to 11 days storage. Soluble solids and titratable acidity varied between years, storage regimes, and maturities. Strong interactions of treatment and year concealed possible treatment effects on these indices. GA3 fruit contained fewer surface pits in one year while CH2N2 fruit suffered less shrivel in another. The earlier harvest date for CH2N2 fruit often avoided higher field temperatures and the resulting promotion of postharvest shrivel. Pitting and shrivel were more prevalent in stored fruit. Brown stem discoloration developed in storage, occurring most frequently in mature fruit, although methyl bromide-fumigated fruit were particularly susceptible. This disorder was more common in GA3 fruit during years of high incidence. Chemical names used: gibberellic acid (GA3); calcium ammonium nitrate (CaNH4NO3); hydrogen cyanamide (CH2N2).
Mowing Height Effects on Summer Turf Growth and Physiological Activities for Two Creeping Bentgrass Cultivars
Authors: Liu Xiaozhong , Huang Bingru
Published: February 2019

Low mowing increases ball roll distance on putting greens, but may affect growth and physiological responses to summer heat stress. The objective of this study was to examine whether the effect of mowing heights on turf summer performance was associated with changes in photosynthetic activities and respiration rate for two creeping bentgrass [Agrostis palustris (L.) Huds] cultivars, `Crenshaw' and `Penncross'. Both cultivars were grown under USGA-specification putting green conditions from 1997 to 1998. Grasses were mowed daily at a 3-mm (low mowing) or 4-mm (high mowing) height. Turf quality, net photosynthesis rate (Pn), and leaf photochemical efficiency (Fv/Fm) declined, whereas respiration rate of whole plants, canopy minus air temperature, and soil temperatures increased under low mowing compared to those at the high mowing height. The decline or increase in those parameters under low mowing was more pronounced in summer than in spring or fall months. The results showed that turf quality was better at the 4-mm mowing height, especially during summer months. Better quality at the higher mowing height could be related to the maintenance of higher photosynthetic activities and lower respiration rate. Mowing at the lower height had more adverse effects on turf growth and photosynthetic capacity for `Penncross' than `Crenshaw', particularly during summer months.
Large-scale Field Trials of Imidacloprid for Control of the Spined Citrus Bug
Authors: Mo J. , Philpot K.
Published: February 2019

Four large-scale field trials were carried out in 2001 and 2002 in lemon orchards in south-western New South Wales to assess the suitability of imidacloprid as a replacement for endosulfan in controlling the spined citrus bug (SCB), Biprorulus bibax Breddin (Hemiptera: Pentatomidae). The results showed that imidacloprid was at least as effective as endosulfan in controlling SCB, even when it was applied at a rate corresponding to half of its discriminate dose (100% kill). The application of imidacloprid did not reduce numbers of wasps and spiders foraging in tree canopies. However, imidacloprid was more toxic than endosulfan to parasitoids of the red scale and to lacewings. These negative effects can be minimised by timing the sprays in winter, when SCB adults congregate in neighbouring orange trees and the numbers of natural enemies of citrus pests are generally low.
Evaluation of Resistance to Plum Pox Virus of North American and European Apricot Cultivars
Authors: Martínez-Gómez P. , Rubio M. , Dicenta F.
Published: February 2019

The resistance to a Dideron isolate of Plum pox virus, which causes sharka disease, of four apricot (Prunus armeniaca L.) cultivars from North America (`Harlayne', `Henderson', `Sunglo', and `Veecot') and a Greek cultivar Lito (a cross of American cultivar Stark Early Orange × Greek cultivar Precoce Tirynthos) was evaluated. `Stark Early Orange' and `Canino', previously rated as resistant and susceptible respectively, were included as controls. Resistance, herein, was defined as inability to infect plants by graft-inoculation and negative assays by enzyme-linked immunosorbent assay. Cultivars found to be resistant were: `Harlayne', `Henderson', `Sunglo', `Lito', and `Stark Early Orange'. Cultivars Veecot and Canino were susceptible.
Berry Texture of Table, Wine, and Dual-purpose Grape Cultivars Quantified
Authors: Sato Akihiko , Yamada Masahiko
Published: February 2019

The textural properties of grape berry flesh were evaluated with a puncture test using a total of 87 cultivars, consisting of 62 vinifera cultivars (Vitis vinifera L.) and 25 labruscana cultivars (Vitis labruscana Bailey) in order to search cultivars with crisp flesh texture for table grape breeding. Crisp texture is the most desirable texture for tableuse, and was determined as easy breakdown on mastication and firm flesh, which was measured as small deformation at the first major peak (DFP) and large maximum force (MF), respectively, in force-deformation curve of the test. For the vinifera cultivars, the mean values of DFP and MF were significantly smaller and larger in table-use cultivars than wine-use and dual-purpose cultivars, respectively. The result indicated that the vinifera wine-use and the dual-purpose cultivars had soft and non-crisp flesh. Based on the puncture tests, the cultivars with a crisp texture (2.5 mm ≥ for DFP and 0.9 N ≤ for MF) were limited to 11 vinifera table-use cultivars such as `Baladi', `Cardinal', and `Muscat of Alexandria'; and one vinifera dual-purpose cultivar (`Terbash'). The DFP was generally high in labruscana cultivars, which include table-use and dual-purpose cultivars, resulting in lacking cultivars with crisp texture among labruscana cultivars. These results indicate that the cultivars with a crisp texture were restricted to a small source within vinifera cultivars.
Soil Amendments Reduce Roof Garden Weight and Influence the Growth Rate of Lantana
Authors: Panayiotis Nektarios , Panayiota Tsiotsiopoulou , Ioannis Chronopoulos
Published: February 2019

Four substrates were investigated for their efficacy as roof garden vegetative layers. The substrates comprised a sandy loam soil (S), sandy loam soil amended with urea formaldehyde resin foam (S:F) in a proportion of 60-40 v/v, sandy loam soil amended with peat and perlite (S:P:Per) in a proportion of 50-30-20 v/v and peat amended with urea formaldehyde resin foam (P:F) in a proportion of 60-40 v/v. The substrates were evaluated for their physical and chemical properties and their capacity to sustain growth of Lantana camara L. Physical and chemical evaluation included weight determination at saturation and at field capacity, bulk density determination, water retention, air filled porosity at 40 cm, pH and EC. When compared to the control (S) a weight reduction of 16.8%, 23.9% and 70.3% was obtained at field capacity with S:F, S:P:Per and P:F substrates respectively. Bulk density was reduced by 46%, 43% and 95%, in substrates S:F, S:P:Per and P:F, respectively, compared to the control substrate S. Air-filled porosity at 40 cm was slightly increased for substrate S:F while it was substantially increased for substrate P:F. The pH response between the initiation and the termination of the study was similar for the four substrates. EC decreased in substrates S and S:P:Per but increased in substrates S:F and P:F. Plant growth was monitored as shoot length, shoot number, main shoot diameter and the number of buds and flowers. Substrates S and S:F resulted in similar plant growth, while substrate S:F promoted flowering. Substrate S:P:Per induced slow plant growth during the first 6 months which subsequently increased resulting in a final growth that was satisfactory and comparable to the S and S:F substrates. Substrate P:F did not support sufficient plant growth and its use should be considered only in special cases where reduced weight of the roof garden is imperative.
An In Vitro Study of Fungicide Effects on Pollen Germination and Tube Growth in Almond
Authors: Yi Weiguang , Law S. Edward , Wetzstein Hazel Y.
Published: February 2019

In almond [Prunis dulcis (Mill.) D.A. Webb.], fungicide sprays are required to prevent blossom blight, which can infect open flowers. Numerous studies have reported detrimental effects of agrochemical sprays on pollination, fruit set, and yield in tree fruit crops. However, effects of fungicides on pollen germination and growth in almond are little known, particularly those from recently developed active ingredients. In this study we evaluated the effects of commercial formulations of 10 fungicides on pollen germination and tube growth in almond using in vitro assays. Assays conducted at 1/100 recommended field rates (RFR) were effective in delineating differences in almond pollen sensitivity to different fungicides. Captan and azoxystrobin were the most inhibitory, with germination percentages of less than 1% of the no-fungicide control. Germination was not significantly affected by propiconazole and benomyl. Intermediate inhibitory effects on pollen germination were observed with ziram, cyprodinil, maneb, thiophanate-methyl, iprodione, and myclobutanil. In contrast to germination, tube growth was less affected by the presence of fungicide. In pollen that germinated, tube elongation was the same as in controls in five of 10 of the fungicides evaluated. Nonetheless, azoxystrobin and captan reduced tube elongation by ≈90%. Some fungicide treatments also influenced tube morphology. In the absence of field evaluation studies, in vitro germination data may provide insight on how specific chemicals may impact pollination processes and further guide in vivo studies, particularly in the case of new chemical formulations.
Growth and Production of Young Peach Trees Irrigated by Furrow, Microjet, Surface Drip, or Subsurface Drip Systems
Authors: Bryla David R. , Trout Thomas J. , Ayars James E. , Johnson R. Scott
Published: February 2019

A 3-year study was conducted in central California to compare the effects of furrow, microjet, surface drip, and sub surface drip irrigation on vegetative growth and early production of newly planted `Crimson Lady' peach [Prunus persica (L.) Batsch] trees. Furrow treatments were irrigated every 7, 14, or 21 days; microjet treatments were irrigated every 2-3, 7, or 14 days; and surface and subsurface drip (with one, two, or three buried laterals per row) treatments were irrigated when accumulated crop evapotranspiration reached 2.5 mm. The overall performance showed that trees irrigated by surface and subsurface drip were significantly larger, produced higher yields, and had higher water use efficiency than trees irrigated by microjets. In fact, more than twice as much water had to be applied to trees with microjets than to trees with drip systems in order to achieve the same amount of vegetative growth and yield. Yield and water use efficiency were also higher under surface and subsurface drip irrigation than under furrow irrigation, although tree size was similar among the treatments. Little difference was found between trees irrigated by surface and subsurface drip, except that trees irrigated with only one subsurface drip lateral were less vigorous, but not less productive, than trees irrigated by one surface drip lateral, or by two or three subsurface drip laterals. Within furrow and microjet treatments, irrigation frequency had little effect on tree development and performance with the exception that furrow irrigation every 3 weeks produced smaller trees than furrow irrigation every 1 or 2 weeks.
Quality and Physiological Changes of Fresh-cut Kohlrabi
Authors: Escalona V.H. , Aguayo E. , Artés F.
Published: February 2019

Fresh-cut diced (1 cm3) kohlrabi (Brassica oleracea L. Gongylodes Group) `Kompliment F1' washed with chlorinated (100 mg·L-1) water was stored in modified atmosphere packaging (MAP) up to 14 days at 0 °C. Samples were packed in 35-μm oriented polypropylene (PP) bags or in plastic trays heat-sealed with unperforated or perforated (control) PP film. Changes in respiratory rate, ethylene emission rate, microbial growth, color, browning, decay, sugar contents, chemical attributes (soluble solids content, pH, and titratable acidity), and sensory attributes (visual appearance, aroma, flavor, and texture) were monitored. Cutting resulted in an increased CO2 production compared to the whole stem, ranging from 2-fold immediately after cutting, to 8-fold at day 4. The equilibrium atmospheres within bags and trays were 6% O2 plus 13% CO2, and 13% O2 plus 8% to 9% CO2, respectively. In both MAP treatments, microbial development was delayed compared to air (control). The total aerobic counts were lower than 7.7 log CFU/g, which has been defined as are commended limit criteria. No physiological disorders, decay. or off-flavor developed. Therefore, sensory quality attributes were suitable for commercial purposes. However, fresh-cut kohlrabi stored in MAP had slightly better color retention and microbial quality than the control.
Genetic Differentiation of Portuguese Tea Plant using RAPD Markers
Authors: Jorge S. , Pedroso M.C. , Neale D.B. , Brown G.
Published: February 2019

Random amplified polymorphic DNA (RAPD) analysis was used to estimate genetic similarities between Portuguese Camelliasinensis (L.) O. Kuntze (tea plant) accessions and those obtained from the germplasm collections from the Tea Research Foundation of Kenya and from the National Research Institute of Vegetables, Ornamental Plants, and Tea of Japan. The accessions studied are taxonomically classified as C. sinensis, var. sinensis, var. assamica, or ssp. lasiocalyx. A set of 118 ten-base arbitrary primers was tested, of which 25 produced informative, reproducible, and polymorphic banding patterns. These primers were used to amplify DNA from 71 tea plant accessions and produced a total of 282 bands, of which 195 were polymorphic. The phenotypic frequencies were calculated using Shannon's Index and employed in estimating genetic diversity within tea plant populations. Our study demonstrates that tea plant populations, including the Portuguese tea plants, show considerable genetic variability. From the UPGMA cluster analysis based on a matrix using the Jaccard coefficient, it was possible to distinguish the Portuguese tea plants from the remaining accessions. The RAPD markers discriminated the three C. sinensis varieties. Moreover, within each variety cluster, subclusters formed according to geographic distribution. The RAPD analysis also separated the commercially cultivated tea plants from the Taiwanese wild tea plants. The present results show that RAPD analysis constitutes a good method to estimate genetic diversity within C. sinensis, and to differentiate C. sinensis accessions according to taxonomic variety and geographical distribution.