L'ENRACINEMENT DES BOUTURES D'ORME D'AMERIQUE (ULMUS AMERICANA L.) SOUS UN FAIBLE ECLAIREMENT

1960 ◽  
Vol 40 (2) ◽  
pp. 248-258
Author(s):  
C. E. Ouellet
Keyword(s):  
Meteorological Conditions ◽  
Stem Cuttings ◽  
Main Difficulty ◽  
Ulmus Americana ◽  
American Elm ◽  
Satisfactory Method ◽  
Main Factors ◽  
Old Trees

The main difficulty encountered in the propagation of American elm (Ulmus Americana L.) by softwood stem cuttings was the premature wilting of foliage, keeping them from subsequent rooting. Decreasing the natural intensities of illumination in our greenhouse during rooting proved to be a satisfactory method of controlling premature wilting. Good results were generally obtained with an illumination of about 1200 lux. It is believed that the transpiration of cuttings is decreased by the reduction of illumination, which so favours rooting. The effect of illumination has seemed to be influenced by three main factors: 1) The time of raking cuttings during summer; at the end of the summer a somewhat higher degree of illumination was advantageous. 2) Meteorological conditions during the season of taking cuttings; good rooting was still obtained within cuttings taken during very rainy summers and containing a high percentage of moisture even under an illumination lower than 1200 lux. 3) The age of parent-trees; the cuttings coming from old trees seemed to be more influenced by the degree of illumination than those coming from young ones.

scholarly journals Evaluation of 19 American Elm Clones for Tolerance to Dutch Elm Disease

2005 ◽  
Vol 23 (1) ◽  
pp. 21-24 ◽  
Author(s):  
A. M. Townsend ◽  
S. E. Bentz ◽  
L. W. Douglass
Keyword(s):  
Block Design ◽  
Dutch Elm Disease ◽  
Stem Cuttings ◽  
Ulmus Americana ◽  
American Elm ◽  
Foliar Symptoms ◽  
Randomized Block Design ◽  
New Harmony ◽  
Crown Dieback ◽  
Valley Forge

Abstract Rooted stem cuttings of 19 American elm (Ulmus americana L.) cultivars and selections, and rooted cuttings of two non-American elm selections, U. carpinifolia Gleditsch 51 and 970 (U. glabra Huds. x (U. wallichiana Planch. x U. carpinifolia)), along with a group of American elm seedlings, were planted in a randomized block design. When the trees were nine years old, they were inoculated with a mixed spore suspension of Ophiostoma ulmi (Buisman) C. Nannf. and Ophiostoma novo-ulmi Brasier, the causal fungi for Dutch elm disease (DED). Analyses of variance showed highly significant variation among clones in foliar symptoms 4 weeks after inoculation and in crown dieback one and two years after inoculation. After two years, 13 of the American clones showed significantly less dieback than the American elm seedlings, and 18 American clones showed significantly less injury than a randomly chosen, unselected American elm clone, 57845. The American clones with the most DED-tolerance were cultivars ‘Valley Forge,’ ‘Princeton,’ ‘Delaware,’ and ‘New Harmony,’ and selections N3487, R18-2, 290, 190, and GDH. The non-American selections 51 and 970 also exhibited high levels of disease tolerance. Most susceptible were American clones 57845, ‘Augustine,’ Crandall, W590, and the American elm seedlings. The most disease-tolerant American elm selections identified in this study are being evaluated further for possible naming and release to the nursery industry.

scholarly journals Variation among American Elm Clones in Long-term Dieback, Growth, and Survival following Ophiostoma Inoculation

2001 ◽  
Vol 19 (2) ◽  
pp. 100-103 ◽  
Author(s):  
A.M. Townsend ◽  
L.W. Douglass
Keyword(s):  
Height Growth ◽  
Dutch Elm Disease ◽  
Stem Cuttings ◽  
Ulmus Americana ◽  
Growth And Survival ◽  
American Elm ◽  
New Harmony ◽  
Crown Dieback ◽  
Valley Forge

Abstract Rooted stem cuttings of eight American elm (Ulmus americana L.) cultivars or selections, in addition to rooted stem cuttings of two non-American elm cultivars, ‘Prospector’ (U. wilsoniana Schneid.) and ‘Frontier’ (U. carpinifolia Gleditsch x U. parvifolia Jacq.), all planted in a randomized block, split-plot design, were inoculated on either one of two dates in May 1992 with a mixed spore suspension of Ophiostoma ulmi (Buisman) C. Nannf. and Ophiostoma novo-ulmi Brasier, the causal fungi for Dutch elm disease (DED). Crown dieback and survival were recorded once yearly for 7 years following inoculations, and height growth was measured after the sixth growing season. Analyses of variance and regression showed significant differences in disease severity among all clones tested. Among the American elms, crown dieback and mortality over time were least for ‘Valley Forge,’ ‘Princeton,’ and ‘New Harmony; ’ intermediate for ‘Delaware’ and selection R18-2; and greatest for selections 57845 and 11 and the cultivar American Liberty. Dieback and survival of ‘Prospector’ and ‘Frontier,’ the non-American elms, were comparable to that of the more disease-tolerant American elm clones. Height growth on surviving American elms for six years after inoculation was greatest for ‘Valley Forge’ and ‘Princeton’ and least for 57845, 11, and ‘American Liberty.’ Results demonstrate the ability of certain American elm cultivars and selections to respond and then recover from heavy doses of the two fungi which cause DED.

The Microscopy of Compatibility and Incompatibility in Ulmus

1985 ◽  
Vol 43 ◽  
pp. 504-505
Author(s):  
B. L. Redmond ◽  
Christopher F. Bob
Keyword(s):  
Dutch Elm Disease ◽  
Economic Losses ◽  
Hybrid Progeny ◽  
Ulmus Pumila ◽  
Ulmus Americana ◽  
American Elm ◽  
Asian Species ◽  
Ulmus Parvifolia ◽  
Initial Appearance ◽  
Chinese Elm

The American Elm (Ulmus americana L.) has been plagued by Dutch Elm Disease (DED), a lethal disease caused by the fungus Ceratocystis ulmi (Buisman) c. Moreau. Since its initial appearance in North America around 1930, DED has wrought inexorable devastation on the American elm population, triggering both environmental and economic losses. In response to the havoc caused by the disease, many attempts have been made to hybridize U. americana with a few ornamentally less desirable, though highly DED resistant, Asian species (mainly the Siberian elm, Ulmus pumila L., and the Chinese elm Ulmus parvifolia Jacq.). The goal is to develop, through breeding efforts, hybrid progeny that display the ornamentally desirable characteristics of U. americana with the disease resistance of the Asian species. Unfortunately, however, all attempts to hybridize U. americana have been prevented by incompatibility. Only through a firm understanding of both compatibility and incompatibility will it be possible to circumvent the incompatibility and hence achieve hybridization.

Aircraft applications of insecticides in East Africa. XVIII. Attempted control of Glossina pallidipes Aust. with pyrethrum in dense thicket

1969 ◽  
Vol 59 (2) ◽  
pp. 299-305 ◽  
Author(s):  
N. S. Irving ◽  
C. W. Lee ◽  
J. D. Parker ◽  
J. S. S. Beesley
Keyword(s):  
East Africa ◽  
Glossina Pallidipes ◽  
Meteorological Conditions ◽  
Human Settlement ◽  
Complete Eradication ◽  
Tsetse Population ◽  
Aerosol Spray ◽  
Northern Tanzania ◽  
Main Factors ◽  
Settlement Schemes

An experiment was carried out in 1967 to assess the effects and economics of aerial applications of pyrethrum as an aerosol spray against a high density tsetse population consisting mainly of Glossina pallidipes Aust. in northern Tanzania. Complete eradication was attempted, and six applications of a 0·4% w/v solution of natural pyrethrins, synergised with 2% piperony1 butoxide in power kerosene, were applied at three-week intervals over three square miles. Application was from a Cessna 182E fitted with one Micronair rotary atomiser. Populations of G. pallidipes, assessed from fly-path catches, were reduced 95% after three applications. The final three applications had little effect and it was considered that unfavourable meteorological conditions and full leaf cover were the main factors responsible. It is suggested that, in view of the high initial kill of the fly and the possibility of using pyrethrum economically against tsetse for human settlement schemes, further work should be carried out with this insecticide.

scholarly journals The complete chloroplast genome sequence of American elm (Ulmus americana) and comparative genomics of related species

2020 ◽  
Author(s):  
Aziz Ebrahimi ◽  
Jennifer D. Antonides ◽  
Cornelia C. Pinchot ◽  
James M. Slavicek ◽  
Charles E. Flower ◽  
...  
Keyword(s):  
Chloroplast Genome ◽  
Natural Populations ◽  
Rrna Genes ◽  
Trna Genes ◽  
Protein Coding ◽  
Ulmus Americana ◽  
Important Species ◽  
Complete Chloroplast Genome ◽  
American Elm ◽  
Chloroplast Genomes

ABSTRACTAmerican elm, Ulmus americana L., was cultivated widely in USA and Canada as a landscape tree, but the genome of this important species is poorly characterized. For the first time, we describe the sequencing and assembly of the chloroplast genomes of two American elm genotypes (RV16 and Am57845). The complete chloroplast genome of U. americana ranged from 158,935-158,993 bp. The genome contains 127 genes, including 85 protein-coding genes, 34 tRNA genes and 8 rRNA genes. Between the two American elm chloroplasts we sequenced, we identified 240 sequence variants (SNPs and indels). To evaluate the phylogeny of American elm, we compared the chloroplast genomes of two American elms along with seven Asian elm species and twelve other chloroplast genomes available through the NCBI database. As expected, Ulmus was closely related to Morus and Cannabis, as all three genera are assigned to the Urticales. Comparison of American elm with Asian elms revealed that trnH was absent from the chloroplast of American elm but not most Asian elms; conversely, petB, petD, psbL, trnK, and rps16 are present in the American elm but absent from all Asian elms. The complete chloroplast genome of U. americana will provide useful genetic resources for characterizing the genetic diversity of U. americana and potentially help to conserve natural populations of American elm.

scholarly journals SHOOT REGENERATION FROM LEAF TISSUES OF AMERICAN ELM AND SIBERIAN ELM.

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 584f-584 ◽  
Author(s):  
Z. M. Cheng ◽  
N. O. Shi ◽  
L. Tokach ◽  
B. K. Gaschk
Keyword(s):  
Factorial Design ◽  
Shoot Regeneration ◽  
Regeneration System ◽  
Ulmus Americana ◽  
Regeneration Rate ◽  
American Elm ◽  
Wide Range ◽  
Leaf Tissues

Shoot regeneration was obtained from leaf tissues of American (Ulmus americana) and Siberian elm (U. pumila) seedlings germinated in vitro and in greenhouse. Murashige and Skoog (MS, 1962) media supplemented with 4 levels of BA (0, 5, 10, 15, 20 μM) and 3 levels of IBA (0, 2.5, 5.0 μM) were tested in a factorial design to find an optimal hormonal combination for shoot regeneration. Shoot regeneration was obtained from both species within 3-4 weeks in a wide range of media. The highest regeneration rate (50%) of American elm was in the medium containing 10 μM BA and 2.5 μM IBA. Incubation under the light was essential for a higher rate of regeneration. Gelrite was found as a better solidifying agent than agar. The progress is under way to achieve transgenic elms by combining this regeneration system with Agrobacterium-mediated transformation.

Preliminary assessments of shoot cold tolerance for American elm bred for enhanced tolerance to Dutch elm disease

2021 ◽  
Author(s):  
Paul Schaberg ◽  
Paula Murakami ◽  
Christopher F. Hansen ◽  
Gary J. Hawley ◽  
Christian O. Marks ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Cold Tolerance ◽  
Dutch Elm Disease ◽  
Freezing Injury ◽  
Ulmus Americana ◽  
American Elm ◽  
The North ◽  
Cold Tolerant ◽  
Using Data ◽  
Plant Hardiness

Although Dutch elm disease (DED) is the primary threat to American elm (Ulmus americana L.), we hypothesized that shoot freezing injury may also limit tree productivity and survival in the north. We assessed shoot cold tolerance and field winter injury of American elm bred for DED tolerance planted in Lemington, VT. We tested for differences in cold tolerance associated with date, maternal DED tolerance source, paternal sources from plant hardiness zones 5a, 6a and 6b (determined using data from 1996-2005), and the interactions of these. Cold tolerance was greatest in the winter, followed by fall and then spring. For all dates, cold tolerance never differed between maternal DED tolerance sources. However, in mid-winter, paternal sources from zone 5a (coldest zone) were significantly more cold tolerant than sources from zone 6b (warmest zone), and sources from zone 6a were intermediate. Field freezing injury confirmed that shoots were only marginally cold tolerant relative to ambient temperature lows.

scholarly journals Plant signals during beetle (Scolytus multistriatus) feeding in American elm (Ulmus americana Planch)

2017 ◽  
Vol 12 (5) ◽  
pp. e1296997 ◽  
Author(s):  
Brett M. Saremba ◽  
Fiona J. M. Tymm ◽  
Kathy Baethke ◽  
Mark R. Rheault ◽  
Sherif M. Sherif ◽  
...  
Keyword(s):  
Scolytus Multistriatus ◽  
Ulmus Americana ◽  
American Elm ◽  
Plant Signals
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