1,422 research outputs found
Advanced and conventional methods for vegetative propagation of selected lines of oak and cherry.
End of Project ReportTeagasc acknowledges with gratitude the support of the European Commission, ECLAIR, and the Human Capital and Mobility Programme in
the financing of this research project.Oak and wild cherry (Prunus avium) are important broadleaved species. We have identified
superior trees and conserved them by grafting. Methods for the large scale propagation of selected
trees was evaluated using the technology of micropropagation. For oak we could establish shoot
cultures from mature oaks but their propagation rate was too low and difficult for practical
application. With wild cherry micropropagation is a feasible option for large scale production of
selected material.
Genetic fingerprinting technology was developed and applied to oaks. We showed that all material
propagated vegetatively from oak was genetically similar to the original donor tree. Furthermore we
used genetic fingerprinting to analyse a unique stand of elite oaks in Co. Westmeath and determined
that the selected trees were not closely related to each other. The analysis of genetic fingerprints of
16 elite oaks also showed that five of them had an unusual pattern of DNA and one tree was identified as a rare triploid tree.European Unio
High levels of gene flow and genetic diversity in Irish populations of Salix caprea L. inferred from chloroplast and nuclear SSR markers
peer-reviewedBackground
Salix caprea is a cold-tolerant pioneer species that is ecologically important in Europe and western and central Asia. However, little data is available on its population genetic structure and molecular ecology. We describe the levels of geographic population genetic structure in natural Irish populations of S. caprea and determine the extent of gene flow and sexual reproduction using both chloroplast and nuclear simple sequence repeats (SSRs).
Results
A total of 183 individuals from 21 semi-natural woodlands were collected and genotyped. Gene diversity across populations was high for the chloroplast SSRs (H
T
â=â0.21-0.58) and 79 different haplotypes were discovered, among them 48% were unique to a single individual. Genetic differentiation of populations was found to be between moderate and high (mean G
ST
â=â0.38). For the nuclear SSRs, G
ST
was low at 0.07 and observed heterozygosity across populations was high (H
O
â=â0.32-0.51); only 9.8% of the genotypes discovered were present in two or more individuals. For both types of markers, AMOVA showed that most of the variation was within populations. Minor geographic pattern was confirmed by a Bayesian clustering analysis. Gene flow via pollen was found to be approximately 7 times more important than via seeds.
Conclusions
The data are consistent with outbreeding and indicate that there are no significant barriers for gene flow within Ireland over large geographic distances. Both pollen-mediated and seed-mediated gene flow were found to be high, with some of the populations being more than 200Â km apart from each other. These findings could simply be due to human intervention through seed trade or accidental transportation of both seeds and pollen. These results are of value to breeders wishing to exploit natural genetic variation and foresters having to choose planting material.Teagasc Walsh Fellowship Programm
Collection and rejuvenation of rare/scarce plants for the nursey stock industry.
End of Project ReportThe main objectives of this project were:
âą Location of scarce/rare or new plants of high garden merit with tolerance to disease and
pests
âą Rejuvenation.
âą Conservation of rejuvenated plants in the original gardens from which they were
collected, at the Kinsealy Research Centre and in other selected locations.
âą Evaluation of the collection for a variety of uses â foliage, patio etc. over a range of
different conditions and locations.
âą Plant identification.
âą Commercialisation of these plants by the trade to extend their range of plants.European
Union Structural Funds (EASSF
Ash dieback on the island of Ireland
Book sectionThis publication is based on the work of Action FP1103 FRAXBACK,
supported by COST (European Cooperation in Science and Technology)On the island of Ireland it is estimated that there are over half a million kilometres of hedgerows (400,000+ km
in the Republic of Ireland (Rep. Ireland) and 113,000+ in Northern Ireland (Northern Ireland). Ash (Fraxinus
excelsior) is the second most important component, after hawthorn (Crataegus monogyna), in large proportions
of this hedgerow network. In the Rep. Ireland over 20,000 ha of ash have been planted since 1990, primarily for
sawlogs and to provide material for the manufacture of hurleys, which are used in an important national sport
called hurling, and for camogie sticks used to play camogie. Ash dieback, caused by Hymenoscyphus fraxineus,
was first identified on the island in October 2012 and since then has been detected at 306 sites (195 in Rep.
Ireland and 111 in Northern Ireland). In the vast majority of cases the outbreaks have been on young, imported
trees planted within the previous 5 â 6 years and it was evident that the pathogen had been introduced on trees
for planting. On a small number of occasions there was evidence of the pathogen cycling within a plantation or
moving from the plantation to infect neighbouring hedgerow trees. One possible mechanism by which the
pathogen can build up sufficient inoculum is by the formation of apothecia on infected woody tissue high up on
the plants. Rep. Ireland and Northern Ireland have strict policies of eradication and containment, as set out in the
All-Ireland Chalara Control Strategy. To date over 2.1 million trees have been destroyed as part of an
eradication strategy. It is considered that this prompt and far-reaching action has had a significant impact,
significantly mitigating and preventing the rapid establishment of the pathogen and limiting its spread. The
interventions since the disease was first confirmed have helped to protect the considerable investment in ash
plantations of the last 20 years. The pathogen has not, however, been eradicated from the island of Ireland and it
remains to be seen how widespread, and how quickly ash dieback will become established on the island of
Ireland. The latest figures from the Republic of Ireland are that 733 hectares of ash plantation has been
reconstituted with another species as a result of Chalara and this has cost our state âŹ2.6 million so far; in
addition, Chalara has been found and confirmed in all 26 counties of the Republic of Ireland to a greater or lesser
extent. As a result the current policies and procedures regarding Chalara are under review.This publication is based on the work of Action FP1103 FRAXBACK,
supported by COST (European Cooperation in Science and Technology
Detection and isolation of exotic Newcastle disease virus from field-collected flies.
Flies were collected by sweep net from the vicinity of two small groups of "backyard" poultry (10-20 chickens per group) that had been identified as infected with exotic Newcastle disease virus (family Paramyxoviridae, genus avulavirus, ENDV) in Los Angeles County, CA, during the 2002-2003 END outbreak. Collected flies were subdivided into pools and homogenized in brain-heart infusion broth with antibiotics. The separated supernatant was tested for the presence of ENDV by inoculation into embryonated chicken eggs. Exotic Newcastle disease virus was isolated from pools of Phaenicia cuprina (Wiedemann), Fannia canicularis (L.), and Musca domestica L., and it was identified by hemagglutination inhibition with Newcastle disease virus antiserum. Viral concentration in positive pools was low (<1 egg infectious dose50 per fly). Isolated virus demonstrated identical monoclonal antibody binding profiles as well as 99% sequence homology in the 635-bp fusion gene sequence compared with ENDV recovered from infected commercial egg layer poultry during the 2002 outbreak
Vegetative propagation of dieback-tolerant Fraxinus excelsior on
book chapterThis publication is based on the work of Action FP1103 FRAXBACK,
supported by COST (European Cooperation in Science and Technology)Ash trees which are tolerant to Hymenoscyphus fraxineus may be selected in all age classes among heavily
infected populations. They may be produced also by controlled crossings of disease tolerant trees, because the
genetic component of inheritance for disease tolerance is high. For mature and juvenile plant material, the
deployment of disease tolerant genotypes could be potentially achieved by vegetatively propagating selected
genotypes. We describe a system to vegetatively propagate selected ash genotypes and we discuss the prospects
and options for using vegetative propagation on all age classes of trees. Mature trees were rejuvenated through
the process of micropropagation to establish mother plants in large trays which were cut back repeatedly
(hedged) to produce at least two crops of cuttings per year.
The rooting capacity of ten genotypes was tested by a commercial nursery over a period of three years, to assess
the feasibility of using hedged mother plants for efficient propagation. Commercial practise was to treat cuttings
with 0.25% IBA, insert them in plug pots and maintain them covered with fine plastic within low plastic tunnels
in a non heated greenhouse and without supplementary heating at the cutting base. In the first year, the mean
rooting rate was 53 % for the first crop of cuttings and 35 % for the second. In the second and third years the
rooting rates improved to over 80% for each crop of cuttings as experience was gained in handling the material.
Rooting rate varied among the genotypes.
We assessed the growth and development of micropropagated ash trees in the field from an observation clonal
trial, consisting of four mature genotypes which had been established in 2002 in five replicate plots. The
micropropagated trees were generally similar in height and dbh to seed derived control trees and developed
normally. These observations are discussed in the context of using vegetative propagation as a tool in breeding
and for the large scale deployment of ash with tolerance to H. fraxineus.European Cooperation in Science and Technolog
Alley coppiceâa new system with ancient roots
International audience& Context Current production from natural forests will not satisfy future world demand for timber and fuel wood, and new land management options are required. & Aims We explore an innovative production system that combines the production of short rotation coppice in wide alleys with the production of high-value trees on narrow strips of land; it is an alternative form of alley cropping which we propose to call 'alley coppice'. The aim is to describe this alley coppice system and to illustrate its potential for produc-ing two diverse products, namely high-value timber and ener-gy wood on the same land unit. & Methods Based on a comprehensive literature review, we compare the advantages and disadvantages of the alley cop-pice system and contrast the features with well-known existing or past systems of biomass and wood production. & Results We describe and discuss the basic aspects of alley coppice, its design and dynamics, the processes of competi-tion and facilitation, issues of ecology, and areas that are open for future research. & Conclusion Based on existing knowledge, a solid founda-tion for the implementation of alley coppice on suitable land is presented, and the high potential of this system could be shown
The Allen Telescope Array: The First Widefield, Panchromatic, Snapshot Radio Camera for Radio Astronomy and SETI
The first 42 elements of the Allen Telescope Array (ATA-42) are beginning to
deliver data at the Hat Creek Radio Observatory in Northern California.
Scientists and engineers are actively exploiting all of the flexibility
designed into this innovative instrument for simultaneously conducting surveys
of the astrophysical sky and conducting searches for distant technological
civilizations. This paper summarizes the design elements of the ATA, the cost
savings made possible by the use of COTS components, and the cost/performance
trades that eventually enabled this first snapshot radio camera. The
fundamental scientific program of this new telescope is varied and exciting;
some of the first astronomical results will be discussed.Comment: Special Issue of Proceedings of the IEEE: "Advances in Radio
Telescopes", Baars,J. Thompson,R., D'Addario, L., eds, 2009, in pres
The Allen Telescope Array Twenty-centimeter Survey - A 690-Square-Degree, 12-Epoch Radio Dataset - I: Catalog and Long-Duration Transient Statistics
We present the Allen Telescope Array Twenty-centimeter Survey (ATATS), a
multi-epoch (12 visits), 690 square degree radio image and catalog at 1.4GHz.
The survey is designed to detect rare, very bright transients as well as to
verify the capabilities of the ATA to form large mosaics. The combined image
using data from all 12 ATATS epochs has RMS noise sigma = 3.94mJy / beam and
dynamic range 180, with a circular beam of 150 arcsec FWHM. It contains 4408
sources to a limiting sensitivity of S = 20 mJy / beam. We compare the catalog
generated from this 12-epoch combined image to the NRAO VLA Sky Survey (NVSS),
a legacy survey at the same frequency, and find that we can measure source
positions to better than ~20 arcsec. For sources above the ATATS completeness
limit, the median flux density is 97% of the median value for matched NVSS
sources, indicative of an accurate overall flux calibration. We examine the
effects of source confusion due to the effects of differing resolution between
ATATS and NVSS on our ability to compare flux densities. We detect no
transients at flux densities greater than 40 mJy in comparison with NVSS, and
place a 2-sigma upper limit on the transient rate for such sources of 0.004 per
square degree. These results suggest that the > 1 Jy transients reported by
Matsumura et al. (2009) may not be true transients, but rather variable sources
at their flux density threshold.Comment: 41 pages, 19 figures, ApJ accepted; corrected minor typo in Table
Bilateral versus single internal-thoracic-artery grafts at 10 years
BACKGROUND Multiple arterial grafts may result in longer survival than single arterial grafts after coronary-artery bypass grafting (CABG) surgery. We evaluated the use of bilateral internal-thoracic-artery grafts for CABG. METHODS We randomly assigned patients scheduled for CABG to undergo bilateral or single internal-thoracic-artery grafting. Additional arterial or vein grafts were used as indicated. The primary outcome was death from any cause at 10 years. The composite of death from any cause, myocardial infarction, or stroke was a secondary outcome. RESULTS A total of 1548 patients were randomly assigned to undergo bilateral internal-thoracic-artery grafting (the bilateral-graft group) and 1554 to undergo single internal-thoracic-artery grafting (the single-graft group). In the bilateral-graft group, 13.9% of the patients received only a single internal-thoracic-artery graft, and in the single-graft group, 21.8% of the patients also received a radial-artery graft. Vital status was not known for 2.3% of the patients at 10 years. In the intention-to-treat analysis at 10 years, there were 315 deaths (20.3% of the patients) in the bilateral-graft group and 329 deaths (21.2%) in the single-graft group (hazard ratio, 0.96; 95% confidence interval [CI], 0.82 to 1.12; P=0.62). Regarding the composite outcome of death, myocardial infarction, or stroke, there were 385 patients (24.9%) with an event in the bilateral-graft group and 425 patients (27.3%) with an event in the single-graft group (hazard ratio, 0.90; 95% CI, 0.79 to 1.03). CONCLUSIONS Among patients who were scheduled for CABG and had been randomly assigned to undergo bilateral or single internal-thoracic-artery grafting, there was no significant between-group difference in the rate of death from any cause at 10 years in the intention-to-treat analysis. Further studies are needed to determine whether multiple arterial grafts provide better outcomes than a single internal-thoracic-artery graft. (Funded by the British Heath Foundation and others; Current Controlled Trials number, ISRCTN46552265.
- âŠ