bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Culture Physical Conditions and Explant Type and Source on the Growth and Multiplication of Ficus benjamina in Vitro
Authors: Al-Khalifah N.S. , Alderson P.G.
Published: February 2019

Shoot cultures of Ficus benjamina cv. Cleo showed a variable response to light intensity in the range of 8 to 50 μmol–m–2–s–1. The highest leaf area occurred at 15 μmol–m–2–s–1 and shoot length and chlorophyll contents increased with the decrease of light intensity. Incubating explants for 8 weeks at 25 and 35C showed that shoot length increased at 35C; however, shoot multiplication, leaf number, root number, and callus weight were higher at 25C. Shoot-tip explants were superior to axillary buds when cultured or subcultured for shoot elongation, whereas axillary buds were better for shoot multiplication. Shoot tips with two or three small leaves appeared to be the best explants for fast growth and healthy cultures of F. benjamina.
Examination of Factors Affecting Transformation of `McIntosh' Apple by Agrobacterium tumefaciens
Authors: Bolar Jyothi Prakash , Brown Susan K. , Norelli John L. , Aldwinckle Herb S.
Published: February 2019

The overall goal of our research is to develop an efficient transformation and regeneration system for `McIntosh' apple. The first objective was to determine the optimum combination of Gelrite (G) and agar (A) to maximize regeneration and minimize vitrification. Treatments included the following combinations of agar (in g–liter–1) and Gelrite (in g–liter–1): 1) 7 and 0; 2) 5.25 and 0.625; 3) 3.5 and 1.875; 4) 1.75 and 1.875; and 5) 0 and 2.5. There were 10 replications, and a single petri plate containing six leaf pieces was the unit of replication. Both 5.25(A) and 0.62(G) and 3.5(A) and 1.25(G) provided high regeneration of healthy, nonvitrified shoots. Since modification of media affects the concentration of antibiotics used in selection due to precipitation of antibiotics, the second objective was to determine the optimal concentration of antibiotic for the selection and regeneration of transformed `McIntosh' on gelrite–agar-based media. Kanamycin was tested at 0, 10, 25, 50, 75, and 100 μg–ml–1 and paromomycin was tested at 0, 50, 100, 150, 200, and 250 μg–ml–1. Antibiotic selection will be discussed relative to optimum concentration and efficiency of selection.
Monitoring Prunus Necrotic Ringspot Virus Infection by Hybridization with a CRNA Probe following in Vitro Grafting
Authors: Heuss-La Rosa K. , Hammond R. , Crosslin J.M. , Hazel C. , Hammerschlag F.
Published: February 2019

In vitro micrografting was tested as a technique for inoculating peach [Prunus persica (L.) Batsch] with prunus necrotic ringspot virus (PNRSV). Cultured `Suncrest' shoots derived from a naturally infected tree (as indicated by ELISA testing) maintained virus in vitro, with virus concentrations in growing tips and folded leaves being several times those of fully expanded leaves. The infected shoots served as graft bases and the source of virus. Grafted tips were derived from `Suncrest' trees that had tested negative for the virus. Leaf samples were collected from the tips following grafting and analyzed for the presence of virus by slot-blot hybridization with a digoxigenin-labeled cRNA probed derived from PNRSV RNA 3. Rates of successful grafting were 55% and 73% in three trials and PNRSV was found in all tips analyzed. Virus concentrations approximated those found in the source shoots, suggesting that this method should be useful for screening transformed peach shoots for coat protein-mediated resistance to PNRSV.
An Evaluation of Antibiotics for the Elimination of Agrobacterium tumefaciens from Apple Leaf Explants in Vitro and for the Effect on Regeneration
Authors: Hammerschlag F.A. , Zimmerman R.H. , Yadava U.L. , Hunsucker S. , Gercheva P.
Published: February 2019

A range of antibiotics was evaluated for their effect on eliminating Agrobacterium tumefaciens supervirulent strain EHA101(pEHA101) from leaf explants of `Royal Gala' apple (Malus domestica Borkh) and on regeneration. After long-term (38 days) exposure to 100-μg–ml–1 concentrations of either cefotaxime (cef), carbenicillin (carb), mefoxin (mef), or combinations of these antibiotics, only on carb or carb with mef was regeneration not inhibited. None of the above antibiotics or antibiotic combinations eliminated A. tumefaciens from leaf explants. Short-term (1-18 hours), vacuum infiltration with 500- to 1000-μg–ml–1 concentrations of either of the above antibiotics did not inhibit regeneration, but did not eliminate A. tumefaciens from leaf explants. After a 30-min vacuum infiltration with a 2000-μg–ml–1 concentration of either cef, carb, or mef, only cef reduced the number of leaf explants with A. tumefaciens.
Somatic Embryogenesis in Muscadine Grape
Authors: Xu Xia , Lu Jiang , Lamikanra O.
Published: February 2019

Low frequency of in vitro regeneration has hampered the adoption of genetic engineering technique for improving the quality of muscadine grape. This study is to develop a straightforward method for high-frequency regeneration of muscadine grapes in vitro. Leaves, petioles, and immature ovules of muscadine grapes were cultured on various media. Embryogenic callus, somatic embryos were formed after 9 weeks inoculated on embryo rescue (ER) medium. The somatic embryos were isolated and subcultured on fresh medium to promote enlargement and increase the number of uniformly sized somatic embryos. Of the medium tested (MS, NN, and ER), the ER medium was the best for somatic embryo growth and multiplication. The somatic embryogenic lines were maintained by transferring the embryos to the fresh ER medium every 4 weeks. Germination was achieved by transferring these embryos to woody plant medium or NN medium. The frequency of somatic embryogenesis of embryo germination appeared to be genotype dependent. The establishment of the somatic embryogenesis system in this study should be a step forward in directly transferring a foreign gene into muscadine grape.
Influence of the Genotype and TDZ on the in Vitro Regeneration of Hybrid Grapes
Authors: Tapia Maritza I. , Read Paul E
Published: February 2019

It has been previously demonstrated that thidiazuron (TDZ) enhanced the regeneration and multiple shoot proliferation of vinifera grape cultivars. To determine the effect of TDZ on the multiplication of hybrid grapes, in vitro nodal segments from cultivars Chancellor, Leon Millot, and Valiant were cultured on MS medium supplemented with 0, 0.01, 0.05, 0.1, 0.5, and 1.0 mg TDZ/liter. After 1 month, the higher percentage of rooted shoots was obtained from the explants cultured in medium containing the lowest concentration of TDZ (0.01 mg–liter–1) independent of the genotype. Multiple shoot proliferation was favored by high concentrations of TDZ (0.5 and 1.0 mg–liter–1). An average of 0.39 and 0.39 shoots, respectively, was obtained from `Chancellor' cultures, 0.56 and 0.59 from `Leon Millot', and 1.93 and 2.38 from `Valiant'. Vitrification and teratological structures were observed in all the cultures of the three genotypes, but less vitrification occurred in `Valiant' plantlets.
Establishment of Parameters for Agrobacterium Transformation of Asparagus Embryogenic Suspension Culture Cells
Authors: May Roger A. , Sink Kenneth C.
Published: February 2019

Conditions for Agrobacterium transformation of asparagus embryogenic suspension cells were investigated using an intron-containing GUS gene in pCNL56 to detect transformation events. Embryogenic suspension cultures of Rutgers 22 were maintained on LS medium with 5 mg NAA/liter, subcultured weekly, and used 5 days thereafter. For initial experiments, cells were inoculated at 5 x 108 cfu/ml for 15 min and cocultivated for 4 days on LS medium with 10 g Phytagel/liter (EM1 medium). Subsequently, the cells were transferred to EM1 with 200 mg Timentin/liter and tested for GUS expression after a total of 6 days. The effect of acetosyringone (AS) on four A. tumefaciens strains was tested. With or without AS induction, EHA105 and C58C1(pMP90) produced a significantly greater number of GUS foci on embryogenic cells than C58C1(pGV2260) and LBA4404. Transient expression was very low from cells inoculated with C58C1(pGV2260) and nonexistent from LBA4404. AS induced significantly more GUS foci from EHA105 and C58C1(pMP90) than from the same noninduced bacteria; however, it had no effect on C58C1(pGV2260). Upon repeating the experiment using EHA105 and C58C1(pMP90) only, no differences in response were observed, although AS induced more GUS foci from both strains and EHA105 outperformed C58C1. Inoculum density was investigated using induced EHA105. 5 x 107 cfu/ml significantly increased the number of GUS foci than 108, 5 x 108, or 109, although it was not statistically different from 107, which produced slightly fewer foci.
RAPD Marker for Sex Determination of Dioecious Plants
Authors: Khandka Deepak K. , Nejidat Ali , Tal Moshe , Golan-Goldhirsh Avi
Published: February 2019

Several horticulturally important species are dioecious (e.g., pistachio, date palm, poplar, and others). It would be advantageous if the gender of a seedling could be determined at the vegetative stage. In this report, we present results of our search for molecular markers for sex differentiation in dioecious species. The method used was bulked segregant analysis of random amplified polymorphic DNA (RAPD) for sex. A male-specific marker fragment OPB01-1470 was obtained in Mercurialis annua. The sex linkage and characterization of this marker will be discussed.
Inoculation- and Fertilization-mediated Changes in Xylem Fluid Chemistry of Soybean and Subsequent Effects on Leafhopper Performance
Authors: Andersen Peter C. , Brodheck Brent V. , Mizell Russell F.
Published: February 2019

The xylophagous leafhopper, Homalodisca coagulata (Say), is an important vector of diseases caused by Xylella fastidiosa (e.g., Pierce's disease, phony peach disease, plum leaf scald, etc.). The nutritional status of xylem fluid has a profound influence on leafhopper distribution, feeding, and performance. Xylem fluid typically consists of 95% to 99% water and contains organic compounds (mainly amino acids and organic acids) in low concentration (i.e., 2 to 8 mM). Successful development of this highly polyphagous leafhopper depended on host-plant chemistry. The reasons for variable success on different host species include variable assimilation efficiency of organic compounds and variable feeding rates. An assessment of nutritional requirements for leafhoppers is an integral component for developing a “whole systems” approach for the biological control of xylem-limited diseases. Soybean (Glycine max L.) was used as a model system in a 2 x 2 factorial experiment, with Rhizobium (inoculation/noninoculation) and fertilization source (urea or nitrate) as the main factors, to assess the influence of specific dietary profiles of xylem fluid on leafhopper performance. These treatments resulted in a high survivorship throughout development (inoculated urea); low survivorship throughout development (noninoculated nitrate); high survivorship for nymphs, but decreasing with age (noninoculated urea); and low survivorship for nymphs, but increasing with age (inoculated nitrate). Consumption rates, maturation time, body weight, and body composition were also correlated to host-plant chemistry.
Preparation and Analysis of Grape Leaf and Petiole Samples by NIR Spectroscopy
Authors: Blatt C.R. , Sinclair P.J. , Batten G.D. , Blakeney A.B. , Welsh L.A.
Published: February 2019

NIR-based tissue analysis has proven useful in Australia for making fertilizer recommendations for rice and wheat growers. Viticulturists have for some time made fertilizer recommendations based on tissue analysis, although there is some debate in the literature as to whether younger or older leaves or petioles provide the best indicator of vine nutrient status for diagnostic purposes. The aim of our research has been to develop NIR-based nutrient analysis for grape producers. Aspects of sample collection, including leaf lamina vs. leaf petiole; leaf opposite the basal cluster vs. youngest leaf; aspects of drying (microwave vs. convection oven), have been reexamined from the viewpoint of convenience, cost, accuracy, and turnaround time with respect to NIR analysis. We have refined procedures for collecting and microwave-drying samples. The samples of leaves and petioles were collected from vines in most wine-growing regions of Australia and included all the major wine grape and some dried fruit cultivars on their own and, in some cases, on rootstocks. At this stage, we have developed preliminary NIR calibrations for the major nutrient elements in both leaf lamina and petioles.
Effect of Boron and Calcium on Lowbush Blueberry Fruit Set, Fruit Characteristics, and Yield
Authors: Chen Youzhi , Smagula John M.
Published: February 2019

Foliar sprays of B (400 ppm), Ca (4000 ppm), B (400 ppm) + Ca (4000 ppm), or water (control) were applied in Sept. 1993 to treatment plots of 12 lowbush blueberry (Vaccinium angustifolium) clones having low leaf B concentrations (<20 ppm). Boron concentration was raised in stem and bud tissue 3 months after application, but Ca concentration was unaffected. Twenty randomly selected stems with four flower buds were tagged in each treatment plot in Apr. 1994 to determine treatment effects on fruit set and fruit characteristics. Blossoms on tagged stems were counted in late May and a count of initial fruit was taken in early July. Initial fruit set was reduced slightly by the Ca treatment, which also resulted in a lower number of flowers per bud. Tagged stems were cut before plot harvest and stored at –15C for final fruit set and fruit characteristic measurements (fruit number, diameter, weight, and firmness, and seed number and size). Treated plots were harvested and weighed in August. Boron and Ca treatments did not increase yields averaged across all clones, but some clones showed a positive response. Yield of Ca-treated plots was significantly lower than the plots without Ca treatment. Effect of treatments on final fruit set and fruit characteristics will be presented.
Net CO2 Assimilation and Foliar Injury of Citrus Leaves Sprayed with Saline Solutions and Urea Nitrogen
Authors: Romero-Aranda R. , Syvertsen J.P.
Published: February 2019

The penetration of foliar-applied urea and salt solutions into citrus leaves was investigated using `Duncan' grapefruit and `Valencia' orange seedlings in a greenhouse, and 8-year-old `Ruby Red' grapefruit trees in field tests during the summer and fall. Net gas exchange rates, Cl, nitrogen, and chlorophyll concentrations of singles leaves were measured during or after the period of foliar applications. Foliar-applied salt treatments increased leaf Cl, and visible burn symptoms were observed when Cl levels reached ≈0.4% of leaf dry weight. After 11 weeks, green areas from salt-treated leaves had similar rates of net CO2 assimilation as control plants. Leaf nitrogen and total chlorophyll increased with repeated sprays. Urea sprayed at 15% caused foliar burn symptoms after two to three applications and increased the amount of leaf abscission. Urea sprayed at 6% increased CO2 assimilation rate ≈50% after three foliar applications in 3 weeks. Nitrogen content and net CO2 assimilation of urea and urea + salt leaves were similar.
Net Carbon Dioxide Exchange Rates of Raspberries at Varying Irradiances, Carbon Dioxide Concentrations, and Air and Soil Temperatures
Authors: Percival David C. , Proctor John T.A. , Tsujita M.J.
Published: February 2019

The influence of irradiance, CO2, and temperature on whole-plant net C exchange rate (NCER) of micropropagated raspberries (Rubus idaeus L. cv. `Heritage') was examined in 1994. Irradiances >1000 μmol–m–2–s–1 PAR were required for light saturation, and net photosynthesis (Pn) greatly increased under CO2 enrichment (up to 2000 μl–liter–1) and was optimum at 17C. Temperature effects were separated in another experiment using varying air and soil temperatures (15, 20, 25, 30, and 35C) under saturated light and ambient CO2 levels (350 μl–liter–1). Both air and soil temperature influenced net Pn, with maximum rates occurring at an air/soil temperature of 17/25C and each contributing 71.2% and 26.7%, respectively, to the total variation explained by a polynomial model (R2 = 0.96). Dark respiration and root respiration rates also increased significantly with elevated air and soil temperatures. Therefore, results from this study indicate that maximum net Pn occurred at an air/soil temperature of 17/25C and that irradiance, CO2 levels, and shoot and root temperatures are all important factors in examining NCER in raspberries.
Development of an Inoculation Protocol for Ericoid Mycorrhizae
Authors: Goulart B.L. , Demchak K. , Yang W.Q. , Stevens C.M. , Dalpe Y.
Published: February 2019

Past experiments have proven that meristem tip-cultured blueberry plantlets are extremely difficult to inoculate using laboratory-grown cultures of existing known isolates of Hymenoscyphus ericae, Scytalidium vaccinii, and Oidiodendron griseum; fungi that have been previously established as ericoid mycorrhizal symbionts. An experiment using both seedling and meristem tip-cultured plantlets was conducted using these proven fungal symbionts from the Canadian Fungal Culture Collection (DAOM), as well as fungi isolated from local blueberry populations at Little Flat, Pa. Treatments included inoculation using soil from the Little Flat population, the same soil (autoclaved), autoclaved soil that was reinoculated with fungi, as well as axenic treatments using H. ericae, S. vaccinii, O. griseum, Little Flat Hymenoscyphus sp., Little Flat Scytalidium sp., and Little Flat Oidiodendron sp. Sampling after 21 days revealed that only the nontreated soil plantlets were infected (≈4%). Results from later sampling dates will be presented, and the mechanism of infection discussed.
Growth and Yield of Greenhouse Tomato with Constant or Intermittent Heating of the Root and Shoot
Authors: Gent M.P.N. , Ma Y.-Z.
Published: February 2019

What is the effect of constant compared to intermittent heating of the shoot and root on growth, nutrient status, and yield of greenhouse tomato (Lycopersicon esculentum Mill)? Seedlings were transplanted on 4 Mar. or 25 Mar. 1994 into troughs heated to 21C by buried tubing, either constantly, or for 12 h during the day or the night, or they were not heated. The greenhouses had either 14/14C or 22/6C day/night minimum air temperatures. After 2 weeks, the 4 Mar. transplants had the greatest leaf weight with constant root heat and least with no heat. Root weight was greater for 14/14 than 22/6 air heat. With 14/14 air heat, only the no root heat reduced leaf weight, whereas with 22/6 air heat, root heat affected leaf weight; the ranking was constant > day > night ≈ no heat. After 2 weeks, the 25 Mar. transplants had least leaf weight with no heat, and other treatments did not differ. Most nutrient concentrations were less in the 25 Mar. compared to the 4 Mar. transplants. The number of fruit, and the number and weight of marketable fruit produced by I July from 4 Mar. transplants was affected by root heat; the ranking was constant heat > day > night > no heat. The 22/6 air heat increased marketable yield, because of fewer small, irregular, and blossom end rot fruit. Root heat had no effect on yield of 25 Mar. transplants. Research supported in part by grant 93-37100-9101 from NRI Competitive grants program/USDA.
The Effects of Shiitake Mushroom [Lentinula edodes (Berk.) Pegler] Strains and Wood Species on the Yield of Shiitake Mushrooms
Authors: Sabota Cathy
Published: February 2019

White and red oak (Quercus spp.), Black Cherry [Prunus serotina (Ehrh.)], Sassafras [Sassafras albidum (Nutt.) Nees], and Eastern Sycamore (Platanus occidentalis (L.)] logs were inoculated, in 12-mm holes drilled 25 mm deep, with eight strains of shiitake mushrooms [Lentinula edodes (Berk.) Pegler]. Logs were then placed in 80% shade houses under natural environment. Harvested mushrooms were counted and weighed and biological efficiency computed. Interactions among strains and seasons of harvest and species and seasons of harvest were significant. The higher producing strains and species produced more mushrooms later in the life of the log than the least productive strains and wood species. White and red oaks produced significantly more than the other wood species. There was only one strain, CW25, that produced significantly less than the top four yielding strains.
Performance of Selected Carrot Cultivars in North Dakota
Authors: Johnson Damon C. , Greenland Richard G. , Radke Rudy , Lee Chiwon W.
Published: February 2019

The Red River valley and surrounding areas of North Dakota are ideal sites for growing high-quality carrots for fresh-market, processing, and dehydrated products. The results of cultivar trials performed for the past 3 years indicate that from 20 to 50 ton/acre of fresh carrots can be produced with or without irrigation in this region. The average sizes of individual carrots are big (260 to 310 g/root) due to high daytime temperatures and large diurnal temperature fluctuations during the growing season. In 1994, the highest yielding carrot cultivars were `Toudo', `Danvers 126', `Delmar', `Babbette', and `Beta III' when evaluated near Absaraka, N.D. Cultivars with highest sugar contents were `Sweetness', `Apache', `Presto', `Comanche', and `Navajo'. A summary of 2-year data on the yield and quality of carrots grown in North Dakota is presented.
Use of Municipal Yard Waste Compost as a Component of Potting Media
Authors: Balch Sandra A. , Auld Dick L. , Durham Richard E.
Published: February 2019

The objective of this study was to assess the feasibility of utilizing composted municipal yard waste as a component of potting media, which is predominantly composed of peatmoss, a nonrenewable and increasingly expensive medium. Green Comet broccoli (Brassica oleracea L. Italica group) was grown in five ratios (1:0, 1:2, 1:3, and 0:1) of composted yard waste: commercial soilless potting medium. Plant heights were recorded weekly. At the end of 6 weeks, measurements were taken on plant height, fresh weight, dry weight, and root: shoot ratios. Media leachate was tested for pH and soluble salt levels. Germination tests were run using the same potting mix ratios. Percent germination and seedling survivability were recorded. Results show that yard waste compost can be used as a component of potting media, although seed germination and seedling growth are inhibited at high compost levels.
Manipulation of Plant Density to Enhance Rice Yield for a Bioregenerative Life-support System
Authors: Goldman K.R. , Mitchell C.A.
Published: February 2019

Rice (Oryza sativa L.) is a candidate crop for use in Controlled Ecological Life-support Systems (CELSS) proposed for a lunar or Mars outpost. `Ai-Nan-Tsao' is a promising semi-dwarf cultivar because growth volume is limited and HI (percent edible biomass) is high. Yield efficiency rate (YER: g grain/m3 per day [g nonedible biomass]-) combines edible yield rate (EYR: g grain/m3 per day) and HI to quantify edible yield in terms of penalties for growth volume, cropping time, and nonedible biomass production. Greenhouse studies indicate EYR increases with plant density from 70 to 282 plants/m2. YER and shoot HI are stable across this density range because nonedible biomass accumulation keeps pace with edible. Tiller number and panicle size per plant decreased with increasing plant density, but total tiller and panicle number per unit area increased to compensate. Density trials in rigorously controlled environments will determine if higher plant densities will produce even greater YER. This research is supported by NASA grant NAGW-2329.
Fruit Growth and Development of Muskmelon (Cucumis melo var. reticulatus Naud.)
Authors: Jenni S. , Stewart K.A.
Published: February 2019

As part of a program to develop a model for growth and development of muskmelon produced under various mulch and row cover combinations, all perfect flowers of five plants were tagged and measured on a daily basis. The polar and equatorial lengths of the inferior ovary were recorded from anthesis to fruit maturity. Mature fruits were harvested at full slip. The location of each flower on the plant was coded. Flowers and subsequent fruits were classified according to the following phenological stages: immature, close to mature, close to full bloom, full bloom, wilted, past full bloom, close to fruit, fruit. The netting was visually evaluated and rated on a scale of 0 to 5, the highest value representing maximum netting. At fruit maturity, the weight, polar and equatorial length of each fruit were measured and mature and immature seeds counted. The number of fruits that reached maturity was directly proportional to the total number of perfect flowers produced on a plant. Fruit weight during growth could be predicted from the polar and equatorial lengths.
Production Environment Influence on Pepper Pungency
Authors: Motes J.E. , Bostian B. , Maness N.
Published: February 2019

The objective of this study was to evaluate the possible causes for greater pungency in pepper (Capsicum annuum) pods of two chile selections when produced at eastern and western Oklahoma locations. Pungency tests over several years have demonstrated that peppers grown in western Oklahoma consistently produce pods with ≈25% greater pungency than peppers grown in eastern Oklahoma. Data from Oklahoma Mesonet stations located near each production location indicated the western Oklahoma location had higher temperatures and wind speed but lower relative humidity than the eastern Oklahoma location during pod development. Mature dry pods were dissected into cap and stem, seeds, and pod wall. Comparisons of pod component differences between the locations showed pods were similar in dry weight; however, western Oklahoma produced more cap and stem in both selections, and in one selection produced more pod wall but less seed. Pungency was 24% and 28% greater in the two selections when grown in western Oklahoma. More pod wall and less seed could account for some of the pungency increase in only one of the selections. The more stressful production environment in western Oklahoma appears to be the major factor in pungency differences between the locations.
Variations in Flowering, Vegetative Growth, and Dry Matter Partitioning Induced by Photoperiod and Temperature Treatments in Papaver somniferum
Authors: Acock Mary C. , Wang Zhongchun , Acock Basil
Published: February 2019

Estimating yields of illicit narcotic crops requires knowledge of how climate, soil, and geography affect these crops. One method for estimating yields is to create databases from which to develop simulation models. This experiment is part of one of those databases, designed to determine if flowering time can be affected in young poppy seedlings by manipulating photoperiod (PP) and temperature. Plants were grown in chambers under a 12-, 13-, 14-, or 24-h PP and a 12-h thermoperiod of 25/20C. Plants at 10 or 20 days after emergence were transferred to separate chambers and treated for 48 h with either a) 10C and a 12-h PP or b) a 24-h PP and a 12-h thermoperiod of 25/20C. Days to flowering (DTF) decreased with increased PP, especially between 12 and 13 h. The 48-h PP interruption decreased DTF for PPs <24 h for both seedling ages, the effect being more pronounced for 10 d and for the 12-h PP. The 48-h 10C interruption had no effect on DTF. The poppy capsule, from which the gum is harvested, was a larger proportion of the shoot biomass under PPs >14 h, but capsule biomass was a positive linear function of DTF. DTF depends on PP and biomass at flowering depends on DTF.
Volatile Oil and Thymol Accumulation in Thymus vulgaris
Authors: Letchamo W. , Mengle C. , Gosselin A.
Published: February 2019

The content of essential oil, thymol, and carvacrol in a thymol-type of clonally selected thyme plants during different developmental stages were investigated under greenhouse and field conditions. Plants in the greenhouse were grown from July to November, under natural light and natural light supplemented by a PPF of 200 μmol·m–2·s–1, provided by HPS lamps, while plants in the field were studied from June to November. Shoot yield and the accumulation of the active principles from greenhouse-grown plants were determined by harvesting the plants at 40-, 60-, and 120-day intervals, while field-grown plants were harvested in August, September, October, and November. Essential oil content, qualitative and quantitative changes in the oil were determined by subjecting the samples to steam distillation and subsequent gas chromatographic analysis. There were important changes in shoot yield, essential oil, thymol, and carvacrol content in the course of plant development. After 120 days of growth under greenhouse conditions, the essential oil content increased by >150%, while thymol content increased by ≈200% compared with the 40-day-old plants. We found some differences in oil content, thymol, and carvacrol accumulation between field- and greenhouse-grown plants. The pattern of crop yield and the accumulation of the major active substances under field and greenhouse conditions are presented and discussed.
Description of the Main Cactus Pear Varieties
Authors: Mondragón-Jacobo C. , Perez-González S.
Published: February 2019

Cactus pear production has been an outstanding activity during the last two decades in central Mexico. It has been devoted mainly to fresh consumption for the national market and for exporting to the USA to a lesser extent. Official statistics report ≈200,000 ton of fresh fruit entering the market every year from June to September. Such a volume is supported on a limited stock of varieties that were originally selected by growers. They were first cultivated in backyards and now as commercial orchards under rainfed conditions. With the exception of `Reyna', there are no formal descriptions of such varieties. This information will be valuable to growers and could provide a background to define breeding goals and strategies. Data was collected in 1992–94 from 12 of the most important cactus pear varieties in central Mexico. The following traits related with fruit quality we registered: fruit weight and color, peel thickness, seed number, and weight and soluble solids. Average fruit size ranged from only 679 in `Charola' to more than 200 g in `Cristalina' with 2.8 and 5.6 g of seeds/fruit, respectively. Commercially, white fleshed fruit is highly appreciated, but there is a wide range from yellow and orange to deep red. Edible portion ranges from 46% in `Cardona' to 64% in `Centenario', while percent soluble solids showed less variability (13.2–15–9), which seems to be strongly influenced by light and temperature at harvest.
Comparison of Chromometer Readings and Sensory Evaluations on Plant Color and Quality
Authors: Adams S.A. , Paparozzi E.T. , Stroup W.W.
Published: February 2019

Plant nutrient treatment differences typically are identified through the use of plant height, leaf quantity, leaf area, and dry weight. Plant color differences may be determined quantitatively, by chromometer, or qualitatively, by sensory evaluations. Chromometer readings are easy an unbiased, however, overall plant quality must be determined by sensory evaluation. In this report, the two evaluation methods are compared. Poinsettias were grown in varying nutrient levels to flowering Chromometer readings were taken on one green leaf and one bract leaf of each flowering plant. Two sensory panels composed of commercial growers/retailers (or trained panel) and consumers, evaluated the mature plants into “Florist”, “Saleable”, or “Non-Saleable” grades. Chromometer and consumer evaluation results were comparable. The trained panel evaluations identified a more specific area of plan acceptance. The chromometer identified only color difference, whereas, the trained panel identified color and plant quality differences. The chromometer and trained panel evaluations, when used together, give complete understanding of treatment effects on quality.
Chemical and Physical Characteristics of Composts Derived from Waxed Corrugated Cardboard and Other Organic Wastes
Authors: Raymond D.A. , Voroney R.P. , Chong C.
Published: February 2019

Composting of organic wastes to use as soil amendments or in potting substrates offers great potential for diversion of these wastes from landfills. The chemical and physical characteristics of 12 composts containing (by volume) spent mushroom substrate (50%), waste waxed corrugated cardboard (WCC, 0%, 25% or 50%), and/or pulverized wood wastes (PWW, 50%, 25%, or 0%) were measured during two separate windrow composting periods (14 to 18 weeks). Supplemental N was added to some of the composts in the form of poultry manure and/or soybean processing wastes. During the first 8 to 10 weeks, composts containing 50% WCC tended to reach and maintain higher temperatures, but subsequently cooled more rapidly. Microbial activity (CO2 evolution) also was initially higher in these composts but fell by week 12 to levels, comparable to composts containing 50% PWW. The paraffin wax in WCC-containing composts was degraded almost completely (>95%). Total N (1.2% to 1.6% DW), P (0.30% to 0.55%), and K (0.9% to 1.2%) concentrations were within, typical ranges but highest in composts containing 50% WCC. KCI-extractable NH4-N (494 mg N/kg) and NO3 + NO2-N (281 mg N/kg) were highest and lowest, respectively, in composts containing 50% WCC. Electrical conductivity (4.5 to 8.5 mS·cm–1) and pH (7.5 to 8.5) were high in all composts and highest in composts with 50% WCC. Concentrations of phenolic compounds were highest in composts containing 50% WCC, manure, and soybean wastes. C:N ratios of all composts were within an acceptable range (18 to 23.1).
Effects of a Legume Winter Cover Crop and Tillage on Production and Nitrogen Nutrition of Sweet Corn
Authors: Cline Gary R. , Silvernail Anthony F.
Published: February 2019

A split-plot factorial experiment was conducted to examine effects of tillage and winter cover crops on sweet corn. Main plots received tillage or no tillage. Cover crops consisted of hairy vetch, winter rye, or a mix. Nitrogen treatments consisted of either adding or not adding NH4NO3 at recommended rates. No significant effects of tillage on sweet corn yields were detected, although yields with tillage were slightly greater. Following rye winter cover crops, adding NH4NO3 to corn significantly (P ≤ 0.05) increased yields by 56% compared to treatments not receiving N. However, following vetch, corn yields obtained without N fertilization equaled those obtained with N fertilization following rye or vetch. It was concluded that 1) nontilled sweet corn was successful and 2) N2 fixed by vetch was able to sustain sweet corn production completely and was equivalent to a minimum of 70 kg N/ha.
Use of Paper De-inking Residues in Potato Production
Authors: Côté S. , Beauchamp C.J. , Yelle S.
Published: February 2019

In 1991, a project was initiated in collaboration with the Daishowa paper company to characterize de-inking residues resulting from paper recycling in detail and to determine the value of this organic residue as an amendment to agricultural soils. Our objective was to determine the effects of field applications of de-inking residues on potato crop culture. In 1992, 1993, and 1994, experimental plots were established and maintained at the Horticultural Experimental Farm of Laval Univ. A factorial design was composed of four replications of four doses of de-inking residues (0, 15, 30, and 45 t·ha–1) combined with four doses of N (0, 45, 90, and 135 kg·ha–1). Treatments were applied to a total of 64 plots. The results indicate the importance of adjusting the fertilization to prevent the immobilization of N by the residues. In 1992, as a result of adding de-inking residues, potato yields were increased significantly when sufficient N fertilizer was added. However, significant decreases in yield were noted when a high level of de-inking residues was applied without any adjustment of the C:N ratio. In 1993, potato yields were reduced in treatments having a second application of residue at the highest doses (30 and 45 t·ha–1), even when additional N was provide. Interestingly, harvested tubers gave no indication of toxicity effects due to heavy metals or other contaminants. Results also will be discussed in terms of overall potato quality and the incidence of disease.
The Use of Rye as a Living Mulch to Control Weeds in Bell Pepper Production
Authors: Reiners Stephen , Wickerhauser Olga
Published: February 2019

The possibility of using annual grain rye (Secale cereale L.) as a living mulch between rows of black plastic mulch was investigated. Rye was seeded immediately after plastic was laid and ≈30 days before transplanting bell pepper (Capsicum annuum L.) seedlings. Rye growth was controlled by postemergence herbicides and mowing or was left unmowed. These treatments were compared to a weedy control, cultivation, and standard preemergence herbicides for their effect on weed control and bell pepper yield. Within the rye treatments, the unmowed rye provided the best weed control and significantly decreased the number and size of weeds between crop rows. The rye cover crop also significantly reduced the yield of peppers. In both the mowed and unmowed rye treatments, total marketable yield was reduced 50% compared to clean cultivated and herbicide-treated plots. Further work is needed to minimize the competition between the living mulch and the crop.
Growth and Yield of Vegetables with Composted Yard Waste Soil Amendment
Authors: Kostewicz S.R.
Published: February 2019

Composted yard waste (CYW) soil applications at rates from 0 to 224 t·ha–1 and with or without preplant fertilizer were evaluated over a 3 years. In year 1, the applications were made in early March, with a succession of crops grown continuously until year 2. During year 2 the entire area was kept as clean fallow, but plot integrity was maintained. Soil samples were taken periodically for chemical analysis. In late March of year 3, a second application of CYW was overlaid on one half of each previously treated plot, and pole beans were grown. Nitrogen tie-up occurred only with the 224 t·ha–1 when no fertilizer was added during year 1 for all crops studied. Where fertilizer was added, no visual symptoms of deficiency occurred with any of the crops; however, with some crops, yields were reduced. CYW application in year 3 resulted in visual symptoms of N deficiency (extreme leaf yellowing) in pole beans along with yield reduction even when fertilizer was added. This was the result of immature CYW used in that year. CYW degradation occurred during the fallow period in year 2, as shown by decreasing organic matter levels in the soil. During year 3, pole bean yields were ≈4% higher where intermediate to high levels of CYW rates were used during year 1 but no additional during year 3 compared to the control plots. In general, CYW for vegetable production was useful when sufficient fertilizer was used to overcome the high initial C:N ratio.
Sustainable Production of Native Aromatic and Medicinal Herbs in Cordoba Province, Argentina
Authors: Affolter James M. , Lagrotteria Marta
Published: February 2019

The province of Cordoba in central Argentina is naturally rich in aromatic and medicinal herbs that are in high demand as ingredients in teas and herbal medicines. Most of the herbs sold are harvested from natural populations, and this activity is a primary source of income for families in the Sierra de Cordoba region. As a result of over-collection and other poor harvesting practices, many native plant populations have been reduced in size or extirpated. The economic consequence of the gradual decline of this resource has been a loss of real income in rural areas coupled with a pattern of emigration from small towns to larger cities. PRODEMA is a collaborative effort by universities in Argentina and the United States, with the sponsorship of the Cordoba government, to domesticate and to market the most commercially important species. Horticultural research has focused on the development of propagation techniques and identification and selection of desirable chemotypes.
Response of Association Vesicular–Arbuscular Mycorrhizal Fungi with Citrus macrophylla W. Rootstock
Authors: Guzmán G.S. , Cuevas O.C.E. , Farias L.J. , Orozco S.M.
Published: February 2019

Citrus macrophylla is an important citrus rootstock for Mexican lemon (Citrus aurantifolia S.). Citrus are highly dependent of vesicular–arbuscular mycorrhizal (VAM) fungi. Four Glomus species were screened for their symbiotic response with C. macrophylla. Seedlings were inoculated with VAM fungi in pots containing sterilized soil. After 3 and 4 months, plants were harvested. Glomus fasciculatum (following by G. intraradices) gave the greatest improvements in growth, resulting in larger plant height and higher shoot dry weight. Glomus aggregatum, G. mosseae, and control plants showed the lowest rates of growth. Plants inoculated with the first three species showed the highest percent of root length colonized. However G. aggregatum gave the highest values of visual density of endophyte in root and soil hyphae. Root colonization and soil hyphae were lowest in plants with G. mosseae.
Comparing Two Methods of Estimating the Population of Indigenous Rhizobia
Authors: M. Marutani , Manalastas E.
Published: February 2019

The growth pouch method and test-tube method were compared to determine to most probable number of indigenous rhizobia population on the island of Guam. Soil samples were collected from three locations, with soil types of Akina, Pulantat, and Guam cobbly clay. Macroptilium atropurpureum and Leucaena leucocephala were used as indicator plants of Bradyrhizobium spp. and Rhizobium spp., respectively. An advantage of the test-tube method is requiring less replenishment of N-free solution during the incubation period. The modified method is used in classrooms to demonstrate the phenomenon of biological N fixation by leguminous plants.
Weed Control Strategies for Field- and Container-grown Herbaceous Perennials
Authors: Swanson Bert T. , Calkins James B.
Published: February 2019

Fourteen herbicides or herbicide combinations, a wood chip mulch, a chipped rubber tire mulch, and a newspaper mulch were evaluated for weed control efficacy and potential phytotoxicity using 12 species of herbaceous perennials under field-growing conditions. Nineteen herbicides or herbicide combinations were similarly evaluated under container-growing conditions using 11 species of herbaceous perennials. The effect of herbicide application time also was monitored through application of herbicides to dormant and actively growing plants. Herbicides and mulch treatments were compared to weeded and nonweeded controls. Herbicide phytotoxicity effects were dependent on the age and species of the herbaceous perennial and herbicide application timing. Herbicide injury was generally greater for newly established plants compared to established plants. Although injury was usually reduced when herbicides were applied to dormant plants, injury was sometimes greater when herbicides were applied in early spring compared to applications made in late spring after complete herbaceous perennial emergence. This effect resulted in injury to young shoots that had emerged before the earliest possible time that herbicides could be applied in early spring. A wood chip mulch provided the most effective weed control and highest quality plants under field growing conditions. Several of the herbicides evaluated demonstrated potential for weed control in both field and container herbaceous perennial production systems and landscape plantings.
Chemical Pinching of Bougainvillea with Off-Shoot-O®
Authors: Norcini Jeffrey G. , Aldrich James H.
Published: February 2019

The response of `Barbara Karst' bougainvillea to the chemical pinching agent Off-Shoot-O® (OSO; methyl esters of fatty acids), was evaluated. Liners were transplanted 4 Apr. 1994 into 3.8-liter containers of soilless medium. OSO at 0 (+pruning), 7.8, 15.6, 31.2, 62.5, 125, and 250 ml·liter–1 was applied over the top on 24 May to 20 replications per OSO concentration and 10 replications per control. On 25 May, OSO was reapplied to 10 replications per OSO concentration. Treatments were applied using a compressed-air backpack sprayer that delivered 82 + 3 and 93 ± 2 liter·ha–1 at 2.8 kg·cm–2 on 24 and 25 May, respectively. Crown phytotoxicity was recorded 1, 2, 7, and 13 days after the initial application on a scale of 0 = no injury to 10 = plant death. A growth index and number of stems <5, 5 to <10, 10 to <15, and >15 cm long were recorded 23 May and 7 July. The best overall response was to the 15.6 + 15.6 ml·liter–1 application, despite the slight but commercially acceptable foliar injury (mean rating = 2.3+0.2). This treatment was similar to the pruned control in growth and number of stems.
Effects of Some Growth Retardants on Shoot and Root Growth of Two Cool-season Turfgrasses
Authors: Al-Mana Fahed A. , Abdel-Kader Hesham H. , Bisarove Ritchard J.
Published: February 2019

Effects of mefluidide, paclobutrazol, and their mixture on shoot and root growth of perennial ryegrass (Lolium perenne L. `Wendy') and creeping red fescue (Festuca rubra L. `Dawson') were studied under container culture. Mefluidide applied alone or in combination with paclobutrazol caused significant reduction in shoot and root growth of perennial ryegrass and red fescue. These treatments also enhanced turf green color of both species and increased their root–shoot percentage, with no major effect on turf quality. Paclobutrazol applied alone reduced shoot height of perennial ryegrass and red fescue by 10% and 32%, respectively, and caused little reduction in their shoot weights, with no effect on turf quality and color. Although paclobutrazol applied alone reduced the root length and percentage of root–shoot dry weight of perennial ryegrass, it did not affect red fescue.
Weed Control Strategies for Wildflower Plantings
Authors: Corley W.L.
Published: February 2019

Several approaches can be taken to minimize weed intrusion of wildflower plantings. To suppress existing weed seeds, the primary and most important cultural practice is proper seedbed preparation. Research has shown that short-term preemergent herbicides, multiple tillings, solarization, and fumigation can result in good weed control during the initial year of wildflower establishment. Other strategies include increased seeding rates, use of aggressive species, and selective herbicides.
Effects of Hydrosource on Growth of Ornamental Annuals in Landscape Beds
Authors: Smalley Timothy J.
Published: February 2019

Ornamental annuals were planted in field beds amended to a depth of 15 cm with 0, 98, 196, or 392 g·m–3 of Hydrosource (Western Polyacrylamide, Castle Rock, Colo.). Hydrosource is a sodium-based, cross-linked, polyacrylamide hydrogel. Salvia splendens `Redtop' and Catharanthus roseus `Peppermint Cooler' were planted on 3 June 1993 and sampled for dry shoot weight and growth index 6 and 12 weeks after planting. Salvia splendens `Red Hot Sally' and Begonia sempervirens `Vodka' were planted on 13 June 1994 in the same beds, with no additional amendments added, and were sampled for dry shoot weight and inflorescence weight 5 and 10 weeks after planting. Plants were irrigated as needed in both years until the first sampling date, and then irrigation ceased. For 1993, a dry experimental period, amending beds with Hydrosource increased dry weight and growth index of both annuals after 12 weeks. In 1994, a wet experimental period, Hydrosource increased shoot weight of plants after 5 weeks, but no differences existed among the weights of the plants after 12 weeks. The inflorescence weight increased with Hydrosource for salvia after 12 weeks. The data indicated that Hydrosource can increase growth of annuals during drought and have no detrimental effect on growth during a wet growing season.