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2
articles listed at this time: Genetically
Modified Organisms Tree
Improvement in Alberta Last Review/Updated:
Dec. 10, 2001 Alberta
Forest Genetic Resources Council - Position Paper Position
Paper - Genetically Modified Organisms (GMO) GMO Definition
Alberta Forest Genetic Resources Council
2001.11.15 GMO, or genetically
modified organism, refers to an organism that, through human intervention
in a laboratory, has had its genome, or genetic code, deliberately altered
through the mechanical insertion of a specific identified sequence of
genetic coding material (generally DNA) that has been either manufactured
or physically excised from the genome of another organism. Genetic modification
may be used to alter any of a wide range of traits, including insect
and disease resistance, herbicide tolerance, tissue composition, and
growth rate. Current
Practice No GMO trees have
been planted in operational forest plantations on Crown lands in Alberta. Council
Position on GMO Trees
- Council Recognizes
the theoretical potential of GMO trees in reforestation;
- Council recognizes
that performance of GMOs and their impact on forest ecosystems are
poorly understood;
- Therefore, in
view of the potential risks currently associated with reforestation
with GMO trees, the Council does not recommend use of GMOs for reforestation
at this time;
- Council recognizes
that research is ongoing and will improve our understanding of the
performance and impact of GMOs;
- Council will
review its recommendation periodically.
Tree
Improvement in Alberta Updated:
July 14, 2003
Position Paper - Tree Improvement in Alberta
Tree Improvement
Alberta Forest Genetic Resources Council
2000.11.06
Tree improvement may be defined as stand yield
enhancement obtained through control of parentage in combination with
good silvicultural practices. Using
traditional methods employed in plant and animal breeding programs,
the best individuals are selectively bred together or vegetatively propagated
to produce more valuable offspring. Traits considered in selection of
parents may include health, growth rate, form, and wood properties. This
process is applied in Alberta in several programs in each of several
native species. Following extensive and long-term testing, several exotic
species may eventually be considered for inclusion in tree improvement
programs, either as parents of hybrids or as pure species. Program
development generally involves the following sequence, but programs
vary considerably in intensity, speed, size and complexity.
- Choose
target species on the basis of ecological suitability, economic value,
expectation of variability, and societal concerns.
-
Conservatively delineate initial breeding region on the basis of ecological
integrity (currently bounded by 2º to 3º latitude by 2º
to 4º longitude, and 400 m elevation range, as well as ecological
parameters).
-
Establish provenance tests and genecological studies within and outside
the breeding region to confirm appropriateness of breeding region
boundaries and to delineate extent and patterns of variation.
- Select
a large number of parents on the basis of good phenotype (expression
of traits of interest such as height, volume, stem straightness, wood
density, freedom from disease) and good geographic coverage of the
breeding region. Ideally, trees selected are close to rotation age
and at least 1.6 km apart.
- Propagate
some or all parents (typically 50-150 parents, with 10-20 copies or
progeny of each) into a seed orchard (and/or clone bank and/or breeding
orchard).
- Collect
seed or vegetative propagules from original wild parents, or make
controlled crosses among grafted ramets in an orchard, and establish
progeny and/or clonal tests to:
-
evaluate parental genotype (genetic worth);
-
estimate genetic parameters, e.g. heritability;
-
estimate genetic gain; and
-
generate a new population for selection of the next generation’s
parents.
- Manage
orchard for regular and abundant production of high quality seed or
vegetative material.
- Progressively
remove (rogue) poorer parents from the orchard as progeny tests yield
estimates of parental value. Limits to roguing will be determined
by seed production and parental numbers.
- Evaluate
tests and move to the next phase of both orchard and breeding program.
Age at evaluation will depend on species and program; for conifers,
it is typically 15-20 years in Alberta. Parents for the next phase
can be chosen through forward selection (selection of individuals
from progeny tests), backward selection (selection of original parents
on the basis of progeny performance) or a combination of both. New
orchards can be de novo, or can gradually replace older ones in a
"rolling front" orchard, where poorer parents are removed
over a period of time and replaced by new selections. Numbers of parents
in an advanced phase orchard will be typically lower, in the range
of 25-50. New breeding population selections are also made from progeny
tests and original parents, on the same basis as new orchard parents,
but in far greater numbers (typically 150 to 300).
- New
material may be introduced into the breeding population at any time.
- Breeding
region boundaries can be adjusted on the basis of provenance and progeny
test results and genecological studies.
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