bluuebunny/crossref_metadata_2025 huggingface dataset:
Planting Date, In-ground Time Affect Cut Flowers of Acidanthera, Anemone, Allium, Brodiaea, and Crocosmia
Authors: Armitage A.M. , Laushman J.M.
Published: October 2019

Various bulbous species were planted during the fall and winter in an attempt to extend harvest periods of cut flowers. In the first year, late planting resulted in later flowering, but shorter stems and reduced yield than early planting; however, some responses were species specific. No differences in flowering due to initial planting times occurred in the subsequent 2 years, regardless of species tested. Anemone coronaria L. and Acidanthera murielae Hoog. ex Perry were productive for 1 year only, but Allium sphaerocephalum L., Brodiaea laxa Wats., and Crocosmia × crocosmiiflora (V.Lem. ex E. Morr.) N.E. Br. were productive for 2 to 3 years. The peak harvest for anemones was 3 to 5 weeks from beginning of harvest, depending on cultivar, and 10 to 20 days from beginning of harvest for crocosmia. Anemone `Mona Lisa' produced longer stems and larger flowers and flowered earlier than `De Caen'.
Production of Fuchsia and Tibouchina Standards Using Paclobutrazol or Chlormequat
Authors: Roberts C.M. , Eaton G.W. , Seywerd F.M.
Published: October 2019

Paclobutrazol treatments of 0, 0.125, 0.250, and 0.500 mg/plant improved the form of Tibouchina urvilleana (DC.) standards and eliminated the need for pruning during the display season. Paclobutrazol did not improve the form of Fuchsia × hybrida Hort. ex Vllm. Paclobutrazol inhibited trunk caliper development in both species. Paclobutrazol at 0.125 mg/plant slightly increased Tibouchina flower size. Chlormequat at 0, 1000, or 2000 mg/plant did not hasten flowering of Tibouchina. Chemical names used: ß-[(4-chlorophenyl) methyl]-α- (1,1-dimethylethyl) -1H-1,2,4-triazole-1-ethanol (paclobutrazol); α-chloro-N,N,N-trimethylethanammonium chloride (chlormequat).
Vegetative Growth Suppression by Paclobutrazol in Greenhouse-grown `Pinot noir' Grapevines
Authors: Reynolds A.G. , Wardle D.A.
Published: October 2019

Paclobutrazol (PB) soil drenches applied at 0, 10, 20, 30, 40, or 50 mg·liter-1 to potted Vitis vinifera L. `Pinot noir' vines inhibited extension growth of shoots on untopped vines and growth of lateral shoots on topped vines. Internode length, leaf area, and cane maturity were also reduced by the PB soil drenches. Foliar application of gibberellic acid (GA3) appeared to remove the effects of PB on the length of some internodes. Chemical name used: β[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).
Abscisic Acid Content in Chilled Tomato Fruit
Authors: Ludford P.M. , Hillman L.L.
Published: October 2019

Free abscisic acid (ABA) was determined in pericarp of mature-green tomato fruit before and after chilling at 2C for 12 days, in chilling-sensitive and chilling-tolerant cultivars. After being ripened at 20C, these fruit were compared with field-ripened fruit. Chilled fruit contained 2 to 3 times the amount of free ABA as did unchilled. The ABA isolation method described involves the use of preparative and analytical high performance liquid chromatography followed by gas chromatography.
Growth and Fruiting of Short-internode Main Dwarf, Normal-internode Parent, and Hybrid
Authors: Knavel Dean E. , Houtz Robert L.
Published: October 2019

Plants of Main Dwarf, a short-internode mutant of the normal-internode `Mainstream' muskmelon (Cucumis melo L.), have shorter internodes, fewer nodes, less total vine length, less total dry weight, smaller leaves, increased chlorophyll concentrations, increased specific leaf dry weight, and increased ribulose-1, 5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39, rubisco) activity per unit leaf area than `Mainstream' plants. Main Dwarf plants produce an equal number of fruit as `Mainstream' plants but are only half their size. Many of the plant and fruit characteristics for F1(Main Dwarf × `Mainstream') are similar to those of `Mainstream', except for greater leaf chlorophyll and rubisco activity per unit leaf area. The F1 (`Mainstream' × Main Dwarf) produced fewer and lower weight fruit than its reciprocal, F1 (Main Dwarf × `Mainstream').
Seed and Embryo Growth in Pod Cultures of Phaseolus vulgaris and P. vulgaris × P. acutifolius
Authors: Sabja Ana Maria , Mok David W.S. , Mok Machteld C.
Published: October 2019

Interspecific hybrid embryos resulting from crosses between Phaseolus species generally fail to reach maturity, and embryo rescue techniques are required to recover plants. To determine if ovary (pod) culture could permit interspecific hybrid embryo development, pods of P. vulgaris L. × P. acutifolius A. Gray and P. vulgaris L. (control) were cultured upright, supported by glasswool, in modified Murashige-Skoog liquid medium. The weight of seeds and length of embryos in P. vulgaris pods increased significantly during culture. However, usually only one or occasionally two seeds located at the middle positions of the pods developed to maturity. The same pod culture procedure promoted precocious germination of early cotyledonary-stage P. vulgaris × P. acutifolius embryos without further maturation of the embryos. These findings confirm that developmental arrest of the interspecific hybrid embryos in vivo is due to intrinsic deficiencies.
BIOASSAY TO DETERMINE CHERRY ROOTSTOCK TOLERANCE TO `BACTERIAL CANKER' CAUSED BY PSEUDOMONAS SYRINGAE PV SYRINGAE
Authors: Krzesinska Elzbieta , Miller Anita Nina
Published: October 2019

An excised twig assay was developed to evaluate cherry geno-types for their tolerance to Pseudomonas syringae pv. syringae. One-year-old wood was collected at monthly intervals from October until January of `Royal Ann', `Corum', and a number of cherry rootstock. The rootstock included; F/12–1 and Giessen (GI) and M × M selections. A 2-cm incision (“^”-shaped flap) was made on each twig. A 20-μl droplet of inoculum or water was placed onto each incision. The inoculum was prepared with one avirulent (K4) and three virulent strains (W4N54, AP2, B15) concentrations (105, 106, or 107 cfu). Inoculated twigs were placed in test tubes and incubated at 15C in high relative humidity for 3 weeks. After incubation, twigs were evaluated for gummosis production (0–3, 0 = no gummosis), incision browning (1–4, 1 = yellow pith), and callus production (0–1, 0 = no callus). The concentration of bacterial suspension had no effect on symptom development. No gummosis or browning was observed on twigs inoculated with water or the avirulent strain. Based on the gummosis and browning ratings, rootstock M × M 2, M × M 39, M × M 60, GI 148-1, GI 154-2, and GI 154-4 were found to be resistant to these three strains of P. syringae in this assay. Root-stock F 12-1, GI 169–15, GI 172–9, and GI 173-9 were found to be tolerant.
Impact of Ozone on Growth of Peach, Apricot, and Almond
Authors: McCool Patrick M. , Musselman Robert C.
Published: October 2019

Almond (Prunus amygdalus Batsch cv. Nonpareil), apricot (Prunus armeniaca L. cv. Royal Blenheim), and peach [Prunus persica (L.) Batsch cv. Halford] grafted nursery stock seedlings were exposed once per week for 4 hours to a maximum O3 concentration of 0.25 μl·liter-1 in field exposure chambers. Exposures were repeated for a total of 4 months in 1986 (year 1) and 1987 (year 2). Trunk caliper, number of shoots, and net growth (total seasonal weight increase) were measured at the end of each year. Almonds appeared to be the most sensitive to O3. Almond seedlings exhibited extensive foliar injury from O3, while apricot and peach seedlings were relatively insensitive. Total net growth of O3-exposed almond was reduced during both years relative to the controls and an impact on caliper was evident after year 2. Apricot seedlings exposed to O3 developed a thinner trunk but more shoots than the controls in both years. Peach tree seedlings exposed to O3 had fewer shoots than the controls at the conclusion of year 2 but thicker trunks after both years. No significant difference in variance or shape of distribution of net growth within the treatment populations between O3-exposed seedlings and controls was detected for any of the three fruit crops. The impact of O3 on young, nonbearing perennial fruit crops may be most evident in specific growth characteristics, such as net growth or trunk caliper.
Nitrogen Leaching from Cypress Wood Chips
Authors: Gilman Edward F. , Yeager Thomas H. , Weigle Diane
Published: October 2019

Columns (4 × 15 cm) of incubated (25C, 7% volumetric moisture) milled cypress [Taxodium distichum (L.) L. Rich] wood chips received 180 mg of each ionic form of N applied to the surface from dry NH4NO3, KNO3, or (NH4)2SO4 and were leached daily with 16 ml deionized water (pH 5.5). After 10 days, >85% of applied N leached from the columns in all treatments. After 25 days, all N leached from the NH4NO3 and KNO3 treatments, and 93% leached from the (NH4)2SO4 treatment. In subsequent experiments, columns received 360 mg N from NH4NO3 and were leached daily with either 16, 32, 48, or 64 ml of deionized water for 50 days. The rate of N leaching increased with increasing water application rate, although total N leached per column was similar for all water rates after 25 days. Columns that received 45, 90, 180, or 360 mg N/column were leached daily with 16 ml of deionized water. Nitrogen concentrations in the leachate ranged from 3406 ppm -N and 2965 ppm -N at day 5 for the 360-mg rate to 3 and 5 ppm, respectively, at day 35 for the 45-mg rate. In all experiments with NH4NO3, more -N leached than -N and more -N leached than applied, indicating vitrification occurred. -N and broadcast over cypress wood chips in the landscape would leach quickly into the soil.
Pistillate Flower Abscission of Walnut—`Serr', `Sunland', `Howard', and `Chandler'
Authors: Catlin P.B. , Olsson E.A.
Published: October 2019

Distillate flower abscission (PFA) was measured for four cultivars of walnut (Juglans regia L.): `Serr', `Sunland', `Howard', and `Chandler'. Mean PFA for `Serr' over 7 years was greater than for the other cultivars and there were no differences among any of the latter. The high PFA potential of `Serr', shown here and earlier, was not expressed in `Sunland', even though both cultivars have one common parent. There was no association of PFA with either of two rootstock. Flowering index did not differ among cultivars and was not related to PFA.
Repellency and Toxicity of a Horticultural Oil against Whiteflies on Chrysanthemum
Authors: Larew Hiram G. , Locke James C.
Published: October 2019

The repellency and toxicity of a petroleum-based proprietary horticultural oil, Sunspray 6E Plus, was tested against the greenhouse whitefly, Trialeurodes vapor-ariorum (Westwood), on greenhouse-grown chrysanthemums [Dendranthema ×grandiflorum (Ramat.) Kitamura cv. Iceberg]. A 2% (v/v) aqueous spray repelled adult whiteflies for at least 11 days after spraying and it was toxic to newly hatched and third stage larval whiteflies. No phytotoxicity was observed when four weekly sprays of 1%, 2%, and 4% oil were applied.
Control of Solanum americanum with Paraquat Impaired by Some Fungicides/Bactericides
Authors: Bewick Thomas A. , Stall William M. , Kostewicz Stephen R. , Smith Kenneth
Published: October 2019

Cupric hydroxide, copper ammonium carbonate, basic copper sulfate, mancozeb, and a combination of cupric hydroxide and mancozeb were applied to American black nightshade (Solanum americanum Mill) before treatment with paraquat at 0.6 kg a.i./ha. Paraquat efficacy was reduced by all fungicides/bactericides, except a flowable formulation of basic copper sulfate, when compared to the herbicide only control. Compared to a surfactant only control, efficacy 1 week after paraquat application ranged from 86% with paraquat only to 42% with a combination of mancozeb and cupric hydroxide. Mancozeb and mancozeb in combination with cupric hydroxide resulted in greater shoot dry weight than the paraquat only control when measured 2 weeks after herbicide application. Chemical names used: 1,1'-dimethyl-4-4'-bipyridinium ion (paraquat); Mn, Zn ethylene bis diethyldithiocarbamate (mancozeb).
Tolerance of Three Apple Cultivars to Ultra-low Levels of Oxygen
Authors: Lau O.L.
Published: October 2019

Tolerance of apples to low levels (0.5%) of O2 was cultivar-dependent. `Spartan' (SP), `Delicious' (RD), and `Golden Delicious' (GD) apples (Malus domestica Borkh.) held for 7 months in 1.0% O2 (with 1.5% CO2) at 0.5C, plus ≈2 months in air at 0C and 7 days in air at 20C, were similar to those held in 1.5% O2. However, incidence of skin injury in fruit held in 0.5% O2 was very high in SP (purple-brown discoloration), low in RD (purple-brown discoloration), but only negligible in GD (lesions). Skin discoloration in SP and RD developed rapidly in air at 20C. Holding in 0.5% O2 improved retention of flesh firmness and juice acidity in GD and, under certain conditions, reduced scald in RD and SP, delayed yellowing in GD, but increased flesh breakdown in SP, flesh browning and alcohol flavor in SP and RD, and core browning in RD.
Soil Contamination Inconsistently Affects Performance of Diphenylamine as a Superficial Scald Inhibitor
Authors: Ingle Morris , Morris J.C. , D'Souza M.C.
Published: October 2019

Three types of soil were mixed with water containing DPA (2000 mg·liter-1) and benomyl (300 mg·liter-1) at 1% to 5% (w/w). `Rome' apples (Malus domestica Borkh.) were dipped in the mixtures over 8 days. The efficiency of DPA as a scald inhibitor was not consistently affected by soil type, soil concentration, or age of mixture. Chemical names used: methyl[1-[(butylamino)carbonyl]-1 H-benzimidazol-2-yl]carbamate (benomyl); diphenldyamine (DPA).
Surface Topology of Chilling Injury of Tomato Fruit
Authors: Dodds Georges T. , Ludford Pamela M.
Published: October 2019

Chilling-injury symptoms on the surface of eight cultivars or lines of tomato (Lycopersicon esculentum Mill.) fruit were mapped with respect to subtending locules. Mature-green (MG) fruit were chilled at SC for 10 to 25 days and then ripened to red ripe at 20C. Mature-green fruit showed a major portion of injury over subtending locules and on the stem end. The location of injury corresponded with the regions that were the last to ripen. The injuries of immature-green (IG) fruit treated in a similar manner were different from those of MG fruit both in appearance and in distribution.
Evaluation of Bean Introductions for Ozone Insensitivity
Authors: Mersie W. , Mebrahtu T. , Rangappa M.
Published: October 2019

Plant introductions of Phaseolus vulgaris L. were grown from seed in a growth chamber and exposed to 0, at 0.6 μl·liter-1 for 2 hours. Plants were assessed for their response to O3 by evaluating percent leaf injury. Of the 410 introductions tested. 17 insensitive. 370 sensitive. and 23 highly sensitive plant introductions were identified.
Daylength Influences Growth and Development of Achimenes Cultivars
Authors: Vlahos J.C.
Published: October 2019

Six cultivars of Achimenes, `Blau Import', `Blauer Planet', `Linda', `Prima Donna', `Schneewittchen', and `Tetraelfe', were grown for 16 weeks under short (SD, 8 hours) or long days (LD, 16 hours) at 21C in a greenhouse. LD increased plant height, shoot mass, number of flowers, and accelerated time to anthesis. SD, depending on the cultivar, increased number of rhizomes. Results show differences in several characteristics of growth and development among the cultivars and that LD promote shoot growth and flowering.
Growth Substance, Light, Fertilizer, and Misting Regulate Propagation and Growth of Golden Pothos
Authors: Wang Yin-Tung
Published: October 2019

Foliar application of 500 or 1000 mg BA or PBA/liter to stock plants of golden pothos [Epipremnum aureum (Linden & Andre) Bunt.] induced axillary bud elongation but did not promote growth of cuttings taken from these stock plants. Cuttings from plants treated with BA + GA4+7, each at 1000 mg·liter-1, died. Plants grown under 1000 μmol·s-1·m-2 had more but smaller leaves than those under 420 μmol·s-1·m-2. Cuttings produced under the higher light level grew more rapidly. Leaf area increased while stem length decreased as Osmocote slow-release fertilizer (18N-2.6P-10K) increased from 4 to 16 kg·m-3. A 24N-3.5P-13.3K water-soluble fertilizer applied at the rate of 0.42 g/500 ml weekly produced the best plants and resulted in the best cutting growth. Cuttings taken from stock plants receiving Osmocote at 4 kg·m-3 grew slower than those produced at other rates. Placement of cuttings in a mist-propagation bed for 1 or more weeks resulted in an accelerated growth rate relative to nonmisted cuttings. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); N-(phenylmethyl)-9-(tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine (PBA); (1α,2β,4aα,10β) 2,4a,7-trihydroxy-l-methyl-8-methylenegibb-3-ene-1,10-dicarboxylic acid l,-4a-lactone (GA4+7).
Germination of Coreopsis lanceolata and Echinacea purpurea Seeds following Priming and Storage
Authors: Samfield Dina Margaret , Zajicek Jayne M. , Cobb B. Greg
Published: October 2019

Seeds of tickseed (Coreopsis lanceolata L.) and purple coneflower [Echinacea purpureo (L.) Moench] were primed in aerated solutions of a 50 mm potassium phosphate buffer at 16C. C. lanceolata seeds were primed for 3 or 6 days; E. purpurea seeds were primed for 6 or 9 days. Seeds were vacuum-stored for 2 months immediately after priming. Identical treatments were imposed on open-stored seeds just before the termination of the storage duration, thus producing four treatments: a vacuum-stored control, an open-stored control, primed vacuum-stored seed, and seed primed after open storage. Although priming significantly improved the performance of C. lanceolata seed, vacuum storage alone also significantly increased the speed of germination and final germination. The advantage of priming was diminished during 2 months of vacuum storage of E. purpurea, but priming enhanced germination as compared with the open-stored nonprimed control. There was little difference between the performance of E. purpurea seeds both primed and vacuum-stored. and the vacuum-stored control.
The Relationship between Maturity Level and Splitting in Poinsettia
Authors: Siraj-Ali Yusef S. , Tayama Harry K. , Prince Thomas L. , Carver Stephen A.
Published: October 2019

The relationship between poinsettia (Euphorbia pulcherrima Willd. ex Kl.) maturity and premature flower bud initiation (splitting) was evaluated. Changes in root growth, phyllotaxy, and heterophylly of `Annette Hegg Dark Red' poinsettia stock plants and cuttings in response to repeated severe pruning (hedging) and the chemical growth regulators gibberellic acid (GA4+7), PBA, or ethephon were evaluated. Cuttings taken from hedged stock plants exhibited a phyllotaxy of 1/3 to 2/5, extensive root growth (characteristics of juvenility in poinsettia), and a low level of splitting (34%). Cuttings taken from nonhedged stock plants exhibited a phyllotaxy of 3/8, reduced root growth (characteristics of maturity in poinsettia), and a high level of splitting 177%). There was a moderate negative correlation (-0.75) between root growth and splitting and a strong positive correlation (0.94) between splitting and phyllotaxy. Cuttings treated with gibberellic acid or PBA exhibited elliptic to ovate leaves (a juvenile characteristic) and levels of splitting ranging from 20% to 90%, depending on concentration and application timing. Untreated cuttings and those treated with ethephon exhibited lobed leaves (an adult characteristic) and levels of splitting ranging from 82% to 100%. Names of the chemical growth regulators were: trihydroxy-1-methyl-8-methylenegibb-3-ene-1,10-dicarboxylic acid 1,-4a-lactone (GA4+7); N-(phenylmethyl)-9-)tetrahydro-2H-pyran-2-yl)-9H-purin-6-amine (PBA); (2-chloroethyl) phosphonic acid (ethephon).
Sugar and Organic Acid Changes in Stored Onion Bulbs Treated with Maleic Hydrazide
Authors: Salama A.M. , Hicks J.R. , Nock J.F.
Published: October 2019

Maleic hydrazide (MH)-treated and untreated (control) onion (Allium cepa L.) bulbs were stored for up to 20 weeks at 0, 15, or 30C with relative humidities (RH) of 40% or 60%. MH and RH had minimal effect on sugars and organic acids in inner or outer scale leaves that were analyzed at S-week intervals. Concentrations of fructose, glucose, and total sugars were higher in inner than outer leaves of the bulb, while the reverse was true for sucrose. Total sugars, glucose, and fructose decreased and sucrose increased with higher storage temperature. Total sugars and glucose decreased with increased storage duration. Malic acid concentration was greater in the outer leaves while citric acid levels were higher in inner leaves. Malic acid increased in onion bulbs during storage while citric acid levels were not influenced by storage duration. Total acids showed little difference across temperatures, due to the concurrent increase in citric acid and decrease in malic acid at 30C.
Estimation of Root Hydraulic Conductivity on Intact Peach and Citrus Rootstock
Authors: Rieger Mark , Motisi Antonio
Published: October 2019

Estimates of root hydraulic conductivity (Lp) were obtained on intact peach (Prunus persica × P. davidiana `Nemaguard') and sour orange (Citrus aurantium L.) rootstock over a broad range of transpiration rates. Within a species, Lp was lower when estimated using the Ohm's law analog than the reciprocal of the slope of the linear regression between transpiration (E) and stem xylem water potential (Ψ). Nonzero y-intercepts in linear regressions of Ψ vs. E resulted in the lack of agreement between Lp estimates. Removal of the root system caused xylem Ψ to rapidly approach zero in both species when E ≈ 0, suggesting that factors responsible for nonzero y intercepts resided within roots. Lp was 2.2 and 3.5 times lower for sour orange than peach when calculated by the Ohm's law and regression methods, respectively.
Screening Pepper Cultivars for Resistance to Flower Abscission: A Comparison of Techniques
Authors: Wien H.C.
Published: October 2019

In one greenhouse and two field experiments, eight or ten pepper (Capsicum annuum L.) cultivars were subjected to low-light stress by use of shade cloth (reducing light by 80%) or to foliar sprays of ethephon at 75 or 150 pi-liter-]. Both low-light stress and ethephon identified `Ace', 'Canape', and. `Belrubi' as less susceptible to flower and flower bud abscission than other cultivars in the first field experiment. In the 2nd year, air mean maxima of 32C caused severe abscission in controls and shaded plants, and complete loss of flowers in those sprayed with ethephon. Abscission of disbudded pedicels was not related to abscission susceptibility of eight cultivars when subjected to shade. While ethephon spray can serve as a satisfactory abscission screening tool under unstressed growing conditions, low-light stress imposed by shading may be used under a wider range of conditions. Chemical name used: 2-chloroethyl phosphoric acid (ethephon).
A Preliminary Analysis of Self-incompatibility in Sour Cherry
Authors: Lansari Ali , Iezzoni Amy
Published: October 2019

Self-incompatibility was investigated in sour cherry (Prunus cerasus L.) by examining pollen growth in the pistil by use of ultraviolet fluorescence microscopy following self- and cross-pollination. The sour cherry cultivars Tschernokorka and Crisana exhibit pollen tube inhibition in the style characteristic of gametophytic self-incompatibility. `Meteor' and `Montmorency' appear to be partially self-incompatible, with few self-pollen tubes reaching the ovary. Several hybrid seedlings from crosses between self-compatible cultivars were self-incompatible, suggesting that these self-compatible parental cultivars carry self-incompatibility alleles.
Heritability of Spring Bloom and Fall Leaf Abscission Dates in Prunus persica
Authors: Hansche Paul E.
Published: October 2019

The heritability of fall leaf abscission and spring bloom date were estimated in a peach breeding stock recently infused with genes of divergent evolutionary origin. One of the two recent progenitors of this breeding stock was evergreen. The other had a high chilling requirement. The heritability of full-bloom date in this breeding stock was estimated to be 0.60 ± 0.08 SD, under the assumption of no outcrossing, and 0.67 ± 0.08 s d, under the assumption of 30% random mating. The heritability of the percentage of leaves abscised by 18 Nov. 1988 was estimated to be 0.33 ± 0.08, under the assumption of no outcrossing, and 0.47 ± 0.08, under the assumption of 30% random mating. The heritability of the percentage of leaves abscised, estimated from data collected on 14 Nov. 1989, was 0.49 ± 0.08, under the assumption of no outcrossing, and 0.55 ± 0.08, under the assumption of 30% random mating. The phenotypic correlation between date of full bloom and percentage of leaves abscised in the following November was estimated to be 0.21; 0.18 t(0.05) > 0.21 > 0.26 t(oo.1). Apparently, these traits readily could be genetically manipulated to circumvent the freeze damage that leads to susceptibility to Cytospora and related disease organisms.
Chromosome Number and Meiotic Behavior of Cultivated Chia, Salvia hispanica (Lamiaceae)
Authors: Estilai A. , Hashemi A. , Truman K.
Published: October 2019

Edible chia seeds, purchased from the local markets in Guatemala, Mexico, and southern California, were used for species identification, chromosome counts, karyotype construction, and meiotic analyses. Plants raised from those seeds had ovate leaves, dense racemose inflorescences, pale-blue flowers, and were identified from herbarium specimens as Salvia hispanica L. Mitotic analyses of root tips from 50 plants showed 2n = 12—the lowest chromosome number in the genus. Chromosomes were small, ranging from 2 to 3.5 pm. One pair of chromosomes was metacentric (with the long arm: short arm ratio, r = 1.5), four pairs were submetacentric (r = 2.6 to 3.6), and one pair was telocentric (r = 12). Meiosis was regular and six bivalents were observed at metaphase I. Ring and rod bivalents averaged 1.53 ± 1.05 and 4.47 ± 1.05, respectively;
In Vitro Rooting of Hypocotyl Cuttings of Fraser Fir
Authors: Saravitz Carole H. , Blazich Frank A. , Amerson Henry V.
Published: October 2019

Hypocotyl cuttings were prepared from Ii-week-old aseptically grown seedlings of Fraser fir [Abies fraseri (Pursh) Poir.] and cultured 18 days on media containing 0 to 40 mg IBA/liter followed by transfer to the same medium without auxin. Greatest rooting (66%) occurred after treatment with 20 mg IBA/liter, whereas the greatest number of roots per rooted cutting (7.4) was noted following treatment with 40 mg·liter-1. Chemical name used: 1H-indole-3-butyric acid (IBA).
The Use of Vesicular-Arbuscular Mycorrhizae in Boston Fern Production: I. Effects of Peat-based Mixes
Authors: Ponton F. , Piché Y. , Parent S. , Caron M.
Published: October 2019

The horticultural Boston fern [Nephrolepis exaltata (L.) Schott cv. Verona] was micropropagated in vitro using commercial techniques. Rooted plantlets were transferred into pots containing one of three test substrates made of peat and vermiculite and subsequently inoculated with one of two species of Glomus. Survival of uninoculated control plants growing on a black peat-based mix was less than that on a brown peat-based mix. Vesicular-arbuscular mycorrhizal (VAM) inoculation significantly increased survival on the former, but not the latter, substrate. The growth of roots was enhanced in brown peatmoss, but VAM colonization was faster with black peatmoss. Compared to uninoculated controls growing under the same fertilization regime, inoculated plants had significantly higher frond P and N concentration and also showed better frond and root growth. On a growth-increment basis, our results suggested that the brown peat-based mixed was more suitable for fungal activity and fern growth.
Greenhouse Disease Screen Facilitates Breeding Resistance to Tomato Early Blight
Authors: Gardner Randokh G.
Published: October 2019

An F2 population segregating for tomato (Lycopersicon esculentum Mill.) early blight resistance derived from C1943 was screened in the greenhouse by spray-inoculating conidia of Alternaria solani (Ellis and Martin) Jones and Grout onto stems of 6-week-old seedlings. Selected F3 lines derived from F2 plants with resistant, intermediate, and susceptible stem lesion reactions were grown in a replicated field trial and evaluated for foliar early blight resistance. Stem lesion and foliar resistance were closely associated, making the greenhouse screen for stem lesion resistance useful in identifying plants with foliar resistance.
Inheritance of Resistance to Early Blight Disease in Tetraploid × Diploid Crosses of Potatoes
Authors: Herriott A.B. , Haynes F.L. , Shoemaker P.B.
Published: October 2019

Heritability of resistance to early blight disease in potatoes (Solarium tuberosum L.) incited by Alternaria solani (En. & Martin) Ser. was estimated in tetraploid × diploid crosses. Susceptible tetraploid cultivars and breeding lines were the female parents. Diploids that produced a high proportion of first-division restitution (FDR) gametes and possessed different levels of early blight resistance were the male parents. Tubers from seedlings that resulted from the tetraploid × diploid crosses were planted in a field and artificially inoculated with spores of Alternaria solani. Resistance was measured as the slope (r) of the regression of the logit of the percent defoliation of each plant vs. time. Higher r values indicated lower resistance. Mean r values ranged from 0.123 to 0.157 for the tetraploid parents, and from 0.054 to 0.116 for the diploid parents. Mean r values for the tetraploid × diploid crosses were intermediate, ranging from 0.077 to 0.143. Narrow-sense heritability (h2) was 0.815. The partial correlation coefficient between r and mean maturity values was – 0.2086.
Shade Increases Susceptibility of Amaranthus hybridus `Quelite' to Pythium Damping-off
Authors: Sealy Ramsey L. , Kenerley C.M. , McWilliams E.L.
Published: October 2019

The effects of three light levels (1403, 806, and 462 μmol·s-1·m-2 on the severity of damping-off caused by Pythium myriotylum Drechsler in Amaranthus hybridus L. `Quelite' were tested. The observed mortality (33%, 69%, and 81%, respectively) decreased as light intensity increased. The reduction in plant growth and maturity in a shaded location is related to the observed increase in suspectibility to damping-off in such an environment.
Priming Dusty Miller Seeds: Role of Aeration, Temperature, and Relative Humidity
Authors: Carpenter William J.
Published: October 2019

Priming permits seeds to slowly imbibe water at regulated rates and to begin the initial stages of germination. Hypertonic polyethylene glycol (PEG) 8000 solutions of 1.0 and 1.2 MPa at 15C improved seed germination of dusty miller (Senecio cineraria DC.). At 0.8 MPa, germination was promoted during priming. No differences in rates, span, or total germination were found among seeds primed for 1, 2, or 3 weeks with or without aeration during priming. Germination percentages of primed and nonprimed seeds were similar at 10, 15, 20, and 25C, but 42% to 81% higher for primed seed at 30 or 35C. Priming reduced days to 50% of total germination (T50) 23% to 61%, and germination spans in days 30% to 67%. Primed seeds germinated most rapidly and uniformly at 20 and 25C. No change in total germination, T50, or germination span resulted when moisture contents of primed seeds were lowered to 7.8% or seeds were held at –80C for 7 days. Primed seed performance was unchanged after storage at 5C and 52% RH for 16 weeks.
Paclobutrazol Bioassay Using the Axillary Growth of a Grape Shoot
Authors: Hunter David M. , Proctor John T.A.
Published: October 2019

A system was developed to evaluate the response of grapes (Vitis spp. `Seyval') to soil-applied paclobutrazol. The youngest fully expanded leaf, and its axillary bud, on single shoots 6 to 9 nodes long developing on rooted softwood cuttings, were retained for use in a bioassay. The shoot that developed from the axillary bud exhibited a dosage-dependent growth inhibition following soil applications of paclobutrazol at 4 dosages between 1 and 1000 μg·g-1 soil. Other aerial components showed no response to paclobutrazol. This test plant system has potential for use in physiological studies with soil-applied plant growth regulators. Chemical name used: β -[(4-chlorophenyl)methyl]- α -(1,1-dimethylethyl)1H-1,2,4-triazole-1-ethanol (paclobutrazol).
Paclobutrazol Spray Timing Influences Apple Tree Growth
Authors: El-Khoreiby Ali M. , Unrath C.R. , Lehman L.J.
Published: October 2019

A single foliar spray of 250 mg paclobutrazol/liter was applied to 7-year-old `Oregon Spur Delicious' (OSD) or `Smoothee Golden Delicious' (SGD) apple trees (Malus domestica Borkh.) at 12 growth stages between tight cluster and petal fall plus 28 days. A linear increase in fruit length and length: diameter ratio and a linear decrease in percent soluble solids content were observed on OSD as sprays were applied later in the season. Russet formation on SGD was excessive if treatment was made between early bloom and petal fall. For both cultivars, best control of shoot growth and minimal change in fruit characteristics occurred when paclobutrazol was applied after bloom. Chemical name used: β -[(4-chlorophenyl)methyl]- α -(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).
Micropropagation of Lowbush Blueberry from Mature Field-grown Plants
Authors: Brissette Line , Tremblay Laurence , Lord Daniel
Published: October 2019

Bud cultures from nonjuvenile field clones of lowbush blueberry (Vaccinium angustifolium Ait.) were established on Z-2 medium with 59 μm 2iP. Reversion to juvenile characteristics with small and rounder leaves occurred only on two explants after 19 weeks in culture. These shoots grew vigorously and could be easily subcultured. The number of shoots of one clone doubled every 23.3 days. Reducing the 2iP concentration to 12.3 and 24.6 μm reduced shoot proliferation, but permitted better shoot elongation. After 5 weeks in a mix of 3 peat: 2 vermiculite: 1 perlite, shoots >20 mm rooted better than shoots measuring 10 to 20 mm. Chemical names used: N-(3-methyl-2-butenyl)-1-H-purine-6-amine (2iP); 1H-indole-3-acetic acid (IAA).
Adsorption of the Herbicides Diuron, Terbacil, and Simazine to Blueberry Mulches
Authors: Hodges Laurie , Talbert Ronald E.
Published: October 2019

Samples of soil, mulch, and the soil/mulch interface zone were collected from commercial highbush blueberry (Vaccinium corymbosum L.) fields typical in their use of mulch under Arkansas conditions. Mulches included 1-year-old hardwood sawdust, 5-year-old hardwood sawdust, and 1-year-old pine needle mulch. Herbicide adsorption (Kd values) of the samples was determined for diuron, terbacil, and simazine. The soils, mulches, and interfaces adsorbed nearly 10 times as much diuron and more than twice as much simazine as terbacil. Adsorption of the herbicides was three to five times greater to the mulches than to the soils. Adsorption was significantly correlated with the organic matter content of the mulch. Adsorption was not related to herbicide solubility. Although no statistical differences were found among the three mulch materials, adsorption coefficients (Kd values) were numerically lower for each chemical on the 5-year-old hardwood mulch than on the 1-year-old hardwood or pine mulch. Chemical names used: 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron); 3- tert -butyl-5-chloro-6-methyluracil (terbacil); 2-chloro-4,6-bis(ethylamine)- s -triazine (simazine).
Short-duration Presprouting, Ethephon, and Cutting Increase Plant Production by Sweetpotato Roots
Authors: Hall Melvin R.
Published: October 2019

Sweetpotato [Ipomoea batatas (L.)] plants were harvested earlier following immersion of roots in 1500 mg ethephon/liter for 10 minutes or cut transversely 1 to 2 cm from the proximal end before bedding than when roots were not treated. Combined ethephon and cutting treatments did not promote earlier harvests than either applied separately. Presprouting for 10 days reduced the time to first plant harvest from whole or cut roots of `Georgia Red', but not from roots of `Georgia Jet'. Immersion in ethephon increased the number of early and total plants produced by both cultivars. Short-duration presprouting and cutting of roots increased the number of early and total plants produced by `Georgia Red', but not by `Georgia Jet'. Total plant production was increased by cutting non-presprouted roots that had been immersed in ethephon. Cutting did not significantly increase total plant production from presprouted roots, but immersion in ethephon increased total number of plants produced from presprouted whole roots. Plant weight and deterioration of the bedded roots during plant propagation were not influenced by treatments. Chemical name used: (2-chloroethyl)phosphonic acid (ethephon).
Prediction of Cucumber Harvest Date Using a Heat Unit Model
Authors: Perry Katharine B. , Wehner Todd C.
Published: October 2019

A heat unit model developed in a previous study was compared to the standard method (average number of days to harvest) for ability to predict harvest date in cucumber (Cucumis sativus L.). Processing and fresh-market cucumbers were evaluated in 3 years (1984 through 1986), three seasons (spring, summer, and fall), and three North Carolina locations. The model predicted harvest date significantly better than the standard method for processing, but not for fresh-market cucumbers.
Kentucky Bluegrass Thatch Characteristics Following Application of Bio-organic Materials
Authors: Berndt W.L. , Rieke P.E. , Vargas J.M.
Published: October 2019

Three bio-organic materials were evaluated at four application rates, based on N contents, for their potential to degrade Kentucky bluegrass (Poa pratensis L.) thatch in a field experiment. Treated thatch was reduced in thickness and had increased earthworm (Lumbricus spp. Hoff.) populations when compared to untreated thatch. Thatch thickness was negatively correlated with level of N (r = –0.91), thatch lignin content (r = –0.94), and earthworm population in the thatch (r = –0.64), and positively correlated with thatch cellulose content (r = 0.62).
Mechanical Thinning of Pecan Fruit
Authors: Smith Michael W. , Gallott James C.
Published: October 2019

Fruit of `Mohawk' in 1986 and 1988 and `Shoshoni' pecan [Carya illinoensis (Wangenh.) C. Koch] in 1986 were thinned during early August using a pecan shaker with modified shaker pads. Fruit removed ranged from 44% to 57% of the crop load. Fruit thinning increased nut size of `Mohawk' in both years, but did not affect nut size of `Shoshoni'. Kernel percentage of thinned `Mohawk' and `Shoshoni' trees increased, and kernel grade of `Mohawk' improved relative to unthinned trees. Return bloom of `Mohawk' was not affected either year by thinning, but return bloom on `Shoshoni' was increased by thinning. Mechanical fruit thinning appears to be a useful commercial tool until better thinning methods are available.
Sulfur Deficiency in Poinsettia
Authors: Dale Mary E. , Paparozzi Ellen T. , Carr James D.
Published: October 2019

Cuttings of Euphorbia pulcherrima Willd. ex Klotzsch `Dark Red Annette Hegg' were grown hydroponically in minus S Hoagland's solution modified to supply 0, 1, 2, 4, or 8 mg S/liter for 8 weeks. Nutrient solution changes; visual observations, sampling of tissue, and measurement of electrical conductivity and pH were done every 2 weeks. Deficiency symptoms appeared after 4 weeks of growth in treatments supplying 0 or 1 mg S/liter and occasionally in treatments supplying 2 mg S/liter. Symptoms included reddening of the petiole and main vein of new leaves followed by yellowing of these leaves. Leaf tissue S levels ranged from 700 to 3600 mg S/kg of plant. Deficient levels were identified as <2200 mg S/kg of plant. Suggested critical tissue levels of S would be 2300 to 3000 mg S/kg of plant leaf tissue.
Rate and Time of Triclopyr Application to Control Virginia Creeper in a Peach Orchard
Authors: Tworkoski T.J. , Young R.S.
Published: October 2019

Triclopyr was applied once or twice in consecutive years to Virginia creeper [Parthenocissus quinquefolia (L.) Planch.] that was growing along the ground beneath the peach [Prunus persica (L.) Batsch.] tree canopy. All rate (0 to 1.1 kg·ha-1) and month combinations controlled Virginia creeper during the season of application. A single application of triclopyr at 1.1 kg·ha-1 was insufficient for control beyond 1 year. Satisfactory control of Virginia creeper was obtained with two applications of triclopyr at 1.1 kg·ha-1 made in either August or September. Chemical name used: [(3,5,6-trichloro-2-pyridinyl)oxy]acetic acid (triclopyr).
Growing Conditions Influence Mite Damage on Apple and Peach Leaves
Authors: Campbell Richard J. , Mobley Kendrick N. , Marini Richard P.
Published: October 2019

The effect of growing conditions on the physiological damage caused by mite feeding was evaluated. Control and twospotted spider mite (Tetranychus urticae Koch)-infested `Imperial Delicious' apple (Malus domestica Borkh.) and `Redhaven' peach [Prunus persica L. (Batsch.)] trees were grown under winter and summer greenhouse conditions. Mite feeding reduced net photosynthesis (Pn) of apple in both winter and summer, with equivalent regression models (Pn on mite days). Total chlorophyll content (TCHL) was decreased, and specific leaf weight (SLW) was increased by mite feeding in both winter and summer. In peach, Pn was also reduced by mite feeding, with equivalent regression models in winter and summer. SLW was unaffected, and TCHL was reduced by mite feeding in both seasons. Transpiration (Tr) of apple and peach was inconsistently affected by mites in winter and summer. In another experiment, control and European red mite (ERM) [Panonychus ulmi (Koch)]-infested `Red-chief Delicious' apple trees were grown in the summer under both greenhouse and field conditions. ERM feeding negatively affected Pn in both the greenhouse and the field, but reductions were less under field conditions. Mites reduced Tr 28% in the greenhouse and 12% in the field. TCHL, SLW, and leaf N content (LFN) were reduced by 16%, 24%, and 26%, respectively, in the greenhouse. In the field, TCHL was not significantly reduced, and SLW and LFN were reduced by 6% and 13%, respectively.
Evaluating the Reaction of Peach Cultivars to Infection by Three Botryosphaeria Species
Authors: Britton K.O. , Hendrix F.F. , Pusey P.L. , Okie W.R. , Reilly C.C. , Daniell J.W.
Published: October 2019

Two field experiments were conducted to assess peach (Prurus persica L.) cultivar susceptibility to the three Botryosphaeria spp. that cause peach tree fungal gummosis. Inoculated trees were evaluated for disease severity by rating gum exudation, vascular discoloration, and fungal colonization. Each severity measurement yielded a different rank ordering of cultivars for susceptibility. However, in a greenhouse study, these same measurements gave consistent rankings for aggressiveness of the fungal species on `Blake'. Despite large differences in disease severity in the greenhouse study, none of the severity measures were correlated with tree growth after inoculation. The only factor significantly correlated with growth rate of the trees after inoculation was growth rate before inoculation.
A Simple System for the Rapid Determination of the Anaerobic Compensation Point of Plant Tissue
Authors: Leshuk Jeffrey A. , Saltveit Mikal E.
Published: October 2019

A method is described for the rapid determination of the anaerobic compensation point (ACP) of plant tissue, i.e., the O2 concentration at which CO2 production is minimum. The rate of CO2 production is measured from tissue exposed to an exponentially declining O2 concentration produced by a flow of N2 into a dilution bottle initially containing air. Too rapid a rate of O2 decline produces abnormal data because of the time required for the tissue to respond to changes in O2 concentration. The ACP is easily determined from a plot of CO2 production vs. O2 concentration. Rates of CO2 production and ACPS calculated using the exponentially declining system are similar to those calculated from traditional methods of continuously holding tissue under various O2 concentrations.
Relative Humidity and Nutrient Concentration Affect Nutrient Uptake and Growth of Begonia × hiemalis
Authors: Gislerød Hans R. , Mortensen Leiv M.
Published: October 2019

Young plants of Begonia × hiemalis Fotsch `Schwabenland Red' were grown for 10 weeks at 60% ± 5% or 90% ± 5% relative humidity (RH) in growth rooms. Plants were watered with three nutrient solution concentrations (1, 2, and 4 mS·cm-1). Transpiration of the plants was 56% lower at the high RH level, while the concentration of the nutrient solution had less effect (10% to 20%). Plant dry weight, height, width, and leaf size were significantly higher at the higher RH. Dry weight, height, width, and leaf size of the plants were higher in the 2 mS·cm-1 than in the 1 mS·cm-1 solution when grown at high RH, but not at a lower RH. A further increase of the nutrient solution concentration either had no effect or was detrimental. The higher RH decreased the concentration of N, P, and K in leaves and stems of plants, but an increase in the concentration of the nutrient solution increased the concentration of N, P, K, and Ca in both leaves and stems. At termination of the experiment, the number of flowers and flower buds and percent of flowering plants was higher at 90% RH than at 60% RH. These values also were higher at the higher nutrient solution concentrations. Time of anthesis was not affected.
Root Growth of Red Maple following Planting from Containers
Authors: Gilman Edward F. , Kane Michael E.
Published: October 2019

Post-planting root development of red maple (Acer rubrum L.) on a well-drained site was compared with that on a site with a high water table. Container-grown red maple planted in 1985 were excavated in 1988 and cross-sectional root area (CSRA) calculated for roots >1 cm diameter, 5 cm beyond the edge of the original container rootball. Adventitious roots were generated in the field after planting, not in the container. Total adventitious CSRA was three times greater than CSRA of roots generated from the original container-produced root system. The number of adventitious roots (7.6) generated from the trunk and primary root after planting was greater than the number of roots originating from the existing root system (4.2). Adventitious root origin on both sites was within 5 cm of the soil surface, above the often circling, kinked, or twisted roots found within the container root ball. Four of the five largest roots were of adventitious origin. Root number, size, and growth rate were not modified by differences in cultural and environmental conditions between sites.
Evapotranspiration of Cool-season Grasses Grown with Minimal Maintenance
Authors: Doty J.A. , Braunworth W.S. , Tan S. , Lombard P.B. , William R.D.
Published: October 2019

Evapotranspiration (ET) of three perennial ryegrass (Lolium perenne L.) cultivars and one cultivar each of colonial bentgrass (Agrostis tenuis L.) and tall fescue (Festuca arundinacea L.) was measured in the field. Soil water depletion was measured with a neutron probe. Under minimal maintenance (i.e., no irrigation and infrequent mowing), ET was not significantly different for five perennial grasses. All grasses used more water than the bare-ground treatment. Soil water uptake was greatest in the upper soil layer (O to 25 cm) and decreased with depth. Few differences in water uptake were noted among grasses within each soil layer.