1. Abdel-Gadir, A.Y., R.L. Krahmer and M.D. McKimmy. 1993.
Relationships between intra-ring variables in mature Douglas-fir trees from
provenance plantations. Wood-and-Fiber-Science 25(2): 182-191.
Keywords: genetic tree improvement
wood
quality
genetic
relationships
Abstract:
Relationships among a variety of densitometric
characteristics of juvenile and mature wood from 360 trees growing in two
plantations of Douglas fir (Pseudotsuga menziesii) in Oregon and Washington were examined. Variables included earlywood
density (EWD) and width (EWW); latewood density (LWD), width (LWW), and
proportion (LWP); average ring density (RD); and total ring width (RW). The RD
components (EWD and LWD) had strong phenotypic and genetic correlations with
their respective RW components (EWW and LWW). However, no phenotypic
correlation existed between average RD and total RW, and genotypic correlation
was weak. The relation between wood density and radial growth
varied by plantation and genotype. It was shown that the potential
exists for improving wood density in juvenile and mature wood by selection,
with only a minor effect on radial growth. Selection during the juvenile period
to improve mature wood quality would be feasible for RD, EWD, LWW, and LWP.
Further, selection to improve juvenile RW would not result in reduced wood
density during maturity.
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2. Adams, W.T., S.N. Aitken, D.G. Joyce,
G.T. Howe and J. Vargas-Hernandez. 2001. Evaluating efficacy of early testing
for stem growth in coastal Douglas-fir. Silvae-Genetica
50(3/4): 167-175.
Keywords: genetic tree improvement
nursery
operations
growth
genetic
relationships
Abstract: In a
test to evaluate the ability to predict stem growth of families in the field
from nursery performance (i.e., early testing), 67 open-pollinated families and
66 full-sib families of coastal Douglas-fir (Pseudotsuga
menziesii var. menziesii)
were sown in two nursery conditions, each replicated as separate experiments:
two bareroot nursery trials established in successive
years in the same nursery, and two container-sown greenhouse trials sown in
different greenhouses in the same year. First year heights in the seedling
trials were compared to mean stem volumes of the same open-pollinated families
in eight 15-year-old field progeny tests and the same full-sib families in
eleven 12-year-old tests. Family mean nursery-field correlations (rxy) were similar for all four seedling trials for both
open-pollinated (OP) and full-sib (FS) families, and generally ranged between
0.30 and 0.40. Although low, it is shown that nursery-field correlations of
this magnitude can be quite useful in tree improvement programmes.
For example, based on the data in this study, it is estimated that a single
stage of family selection for first year seedling height would be about 50% as
effective in improving 15-year volume as direct selection for this trait in
field tests. Early testing, however, is probably of more practical significance
as a tool for culling families prior to out-planting field tests in two-stage selection
schemes. It is estimated that 25% of the OP families in this study could have
been culled in an early test (first stage selection), with gain in 15-year
volume after subsequent field testing and selection of the remaining families
(second stage selection) being nearly the same as if
all families had been field tested. Thus, early testing is an effective tool
for reducing the size and cost of field progeny tests without sacrificing
genetic gain.
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3. Adams, W.T., J. Zuo, J.Y. Shimizu,
J.C. Tappeiner and J.H. Zuo.
1998. Impact of alternative regeneration methods on genetic diversity in
coastal Douglas-fir. Forest Science 44:390-396.
Keywords: planting operations
genetic relationships
Abstract: Genetic
markers (17 allozyme loci) were used to study the
genetic implications of natural and artificial regeneration following 3
regeneration methods (group selection, shelterwood,
and clearcut) in coastal Douglas fir (Pseudotsuga menziesii var. menziesii) forests in the Willamette Valley, Oregon, USA.
In general, harvesting followed by either natural or artificial regeneration
resulted in offspring populations which were very similar to those in the
previous generation. The removal of the smallest trees to form shelterwoods resulted in the removal of rare, presumably
deleterious, alleles. Fewer alleles per locus were observed among residual trees
(2.76) and natural regeneration (2.75) than were found in uncut (control)
stands (2.86). The shelterwood regime appeared quite
compatible with gene conservation, and it was considered that it was best to
leave parent trees of a range of sizes to act as gene conservation reserves, in
order to maximize the number of alleles (regardless of current adaptive value)
in naturally regenerated offspring. Seedling stocks used for artificial
regeneration in clearcut, shelterwood,
and group selection stands (7 total) had significantly
greater levels of genetic diversity, on average, than natural regenerated
seedlings.
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4. Aitken,
S.N. and W.T. Adams. 1996. Genetics of fall and winter cold hardiness of
coastal Douglas-fir in Oregon. Canadian-Journal-of-Forest-Research 26(10): 1828-1837.
Keywords: genetic tree improvement
tree/stand
protection
tree/stand
health
tree
physiology
genetic
relationships
Abstract: Genetic
variation in autumn cold hardiness was studied in two western Oregon breeding populations of coastal Douglas fir (Pseudotsuga menziesii var. menziesii), one on the west slope of the Cascade Mountains and the other in the Coastal Range. On six sampling dates (September, October and November
1992 and January, September and October 1993), shoot cuttings from 40
open-pollinated families in each of two progeny test sites for each breeding
zone were subject to artificial freezing at two test temperatures. Damage in
each shoot was recorded as visible injury to needle, stem and bud tissue
separately. Considerable family variation was found for cold injury scores in
all tissues in early to mid autumn, but differences were often smaller or nonsignificant in late autumn and midwinter. Individual
heritability estimates for needle cold injury were low (<0.40) and generally
decreased in late autumn and midwinter. Family rankings for autumn cold
hardiness, however, are expected to be relatively consistent over sites and
years, although needles appear to display more family-by-site interaction than
stems or buds. Genetic correlations between tissues in cold injury varied
considerably and were sometimes weak, indicating that the evaluation of a
single tissue is probably not adequate for assessing overall cold hardiness of
genotypes. Autumn and winter cold hardiness seem to be largely under separate
genetic control since genetic correlations between hardiness at these two
stages were weak. This study confirms earlier results in Washington breeding populations and shows that coastal Douglas fir
families can be effectively ranked for autumn cold hardiness by conducting
artificial freeze tests on cut shoots in mid-autumn (October) and scoring
damage to stems and at least one other tissue.
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5. Aitken,
S.N. and W.T. Adams. 1997. Spring cold hardiness under strong genetic control
in Oregon populations of Pseudotsuga menziesii var. menziesii.
Canadian-Journal-of-Forest-Research 27(11): 1773-1780.
Keywords: genetic tree improvement
tree/stand
protection
tree/stand
health
tree
phenology
tree
physiology
genetic
relationships
Abstract: Genetic
variation in spring cold hardiness of shoots prior to bud break was studied in
two Oregon breeding populations of Pseudotsuga
menziesii var. menziesii,
one on the west slope of the Cascade Mountains and the other in the Coast Range. In March and April 1993, and April 1994, shoot cuttings
from 40 open-pollinated families in each of two progeny test sites in each
breeding zone were subjected to artificial freezing. Visible cold damage to
needle, stem, and bud tissues was recorded. Date of bud burst (all sites), and
injury resulting from a 1992 natural frost event (one site), were also
recorded. Spring cold injury varied widely among families. Individual heritabilities for spring cold injury scores averaged 0.76
in the Coastal zone and 0.42 in the Cascade zone. Genetic correlations among
tissues, sites, sampling dates, and years, and between April cold injury and
date of bud burst were high, in most cases over 0.80. Correlations were also
strong between natural frost damage in 1992 and artificial cold injury scores
in 1993. Artificial freeze testing stem tissues of cut shoots sampled in April
from a single test site should effectively rank families in this region for
spring cold hardiness.
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6. Aitken,
S.N., W.T. Adams, N. Schermann and L.H. Fuchigami. 1996. Family variation for fall cold hardiness
in two Washington populations of coastal Douglas-fir (Pseudotsuga
menziesii var. menziesii (Mirb.) Franco). Forest-Ecology-and-Management 80(1/3):
187-195.
Keywords: genetic tree improvement
tree/stand
protection
tree/stand
health
tree
physiology
tree
phenology
genetic
relationships
Abstract: In
order to assess the genetics of autumn (fall) cold hardiness in coastal Douglas
fir (Pseudotsuga menziesii
var. menziesii), shoot cuttings were collected in
October from saplings (9-year-old trees) of open-pollinated families in two
progeny tests in each of two breeding zones in Washington, one in the Coast
range (80 families) and one on the west slope of the Cascade Mountains (89
families). Samples from over 5500 trees were subjected to artificial freezing
and visually evaluated for needle, stem and bud tissue injury. The extent to
which cold injury is genetically related to tree height and shoot phenology (timing of bud burst and bud set) was also
evaluated. Significant family variation was found for all cold hardiness
traits; however, individual heritability estimates were relatively low (ranging
from 0.09 to 0.22). Significant family-by-test site interaction was detected
for needle injury in the Cascade breeding zone, but not in the coastal zone.
Genetic correlations (rA) among needle, stem and bud
tissues for cold damage were weak (0.16<less or =>rA<less
or =>0.58) indicating that genes controlling autumn cold hardening are
somewhat different for different tissues. Timing of bud burst and bud set were
only weakly correlated with cold injury (rA<less
or =>0.49). Thus, bud phenology is a poor
predictor of autumn cold hardiness in this species. There was no consistent
relationship between tree height and cold injury in the coastal zone. In the
Cascade zone, taller trees appeared to be more susceptible to cold injury, but
the association was weak (mean rA=0.38, range
0.20-0.72).
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7. Anekonda,
T.S., M.C. Lomas, W.T. Adams, K.L. Kavanagh and S.N. Aitken. 2002.
Genetic variation in drought hardiness of coastal Douglas-fir seedlings from British Columbia. Canadian-Journal-of-Forest-Research 32(10): 1701-1716.
Keywords: genetic tree improvement
tree/stand
protection
growth
tree/stand
health
genetic
relationships
tree
physiology
Abstract: Genetic
variation in drought hardiness traits and their genetic correlations with
growth potential and recovery traits were investigated in 39 full-sib families
of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) from
southwestern British Columbia, Canada. Seedlings of these families were grown in raised nursery
beds and subjected to three moisture regimes each in the second (well-watered
or control, mild, and moderate drought) and third (control, severe drought, and
recovery from second-year moderate drought) seasons. Traits assessed included
drought hardiness (foliage damage, cavitation of
xylem tracheids, xylem hydraulic conductivity, and
height and diameter growth increment) in the drought treatments, growth
potential (total height and diameter) in the control treatment, and height and
diameter growth increments in the recovery treatment. Xylem cavitation
in the growth ring produced in a particular year was nearly three times greater
under the moderate drought and four times greater under the severe drought than
in the control treatment. Xylem hydraulic conductivity of seedlings in the
severe drought treatment was 40% lower than conductivity of seedlings under the
control treatment. Mean foliage damage in seedlings subjected to severe drought
(third season) was much greater (33%) than in seedlings subjected to mild or
moderate drought (second season). Families differed significantly in most
drought hardiness traits, with individual tree heritabilities
averaging 0.19. Thus, much potential exists for identifying drought-hardy
families at the seedling stage and using this information for deployment or
breeding purposes. In addition, most hardiness traits were strongly intercorrelated (genetic correlations often exceeded
|0.80|) indicating that these traits are controlled largely by the same set of
genes and that selection for hardiness based on one trait will increase
hardiness as reflected in the other traits as well. Genetic correlations were
only moderate (0.49) between hardiness traits measured in different years,
perhaps due to the large difference in severity of the drought applied in the
two seasons. Although injury to seedlings, as reflected in foliage damage and
xylem cavitation, was relatively low under the
moderate drought of the second season, it did result in reduced growth
increment the following (recovery) year. Growth potential under favourable moisture regimes was nearly uncorrelated with
drought hardiness, suggesting that drought hardiness could be improved in this
southwestern British Columbia breeding population without negatively impacting growth
potential in favourable moisture conditions.
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8. Barclay, H.J. and Y.A. El-Kassaby. 1988. Selection for cone production in Douglas-fir
adversely affects growth. In
Proceedings: 10th North American Forest Biology Workshop: 'Physiology and
genetics of reforestation', University of British Columbia, Vancouver, British
Columbia, July 10-22, 1988. Eds. J. Worrall, J. Loo-Dinkins
and D.P. Lester. pp. 149-151.
Keywords: genetic tree improvement
genetic
relationships
growth
reproduction
Abstract: Cone
production and radial growth increment were studied for 8 years in a Douglas
fir (Pseudotsuga menziesii)
seed orchard on Vancouver Island, British
Columbia, in 365 trees representing 29 open-pollinated (half-sib)
families. Genetic correlations for the two traits were compared for each of the
8 years. Six of the correlations were significantly negative, while the
remaining two were significantly positive. The predominantly negative
correlation between cone production and growth indicates that selection for one
of these two characters will effectively select against the other. The practice
of selecting for high cone-producing trees in seed orchards may also be
expected to yield slower-growing trees.
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9. Birot, Y. and C. Christophe. 1983.
Genetic structures and expected genetic gains from multitrait
selection in wild populations of Douglas fir and Sitka spruce. I. Genetic variation between and within
populations. Silvae-Genetica 32(5/6): 141-151.
Keywords: genetic tree improvement
genetic
relationships
growth
tree
phenology
tree
morphology
Abstract: For
Douglas fir, 371 open-pollinated progenies from 26 provenances ranging from N.
to S. along the western foothills of the Cascade Mts., Washington, were tested. For Sitka spruce, 292 open-pollinated progenies from 21 provenances
ranging from S.
British Columbia to
middle-Oregon were tested. Observations were made on growth, phenology and form from the nursery stage up to age 12.
Classical patterns of geographic variation were observed for both species.
Heritability and genetic correlations varied from one provenance to another,
especially for Douglas fir, and also changed over time. Sitka spruce showed high additive effects, offering good
prospects of future genetic gains. It was concluded that preliminary
investigations on genetic parameters were necessary before setting up a
breeding strategy.
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10. Copes, D.L. and R.A. Sniezko. 1991. The influence of floral bud phenology on the potential mating system of a wind
pollinated Douglas-fir orchard. Canadian-Journal-of-Forest-Research 21(6):
813-820.
Keywords: genetic tree improvement
tree
phenology
reproduction
genetic
relationships
Abstract: Reproductive
bud phenology was recorded from 1983 to 1989 in a
Douglas fir (Pseudotsuga menziesii)
clonal orchard near Monmouth, Oregon. Potential outcross efficiency was calculated for 20
clones from dates of male and female bud opening and pollination mechanism
information. Potential outcross efficiency was limited to a maximum of 58%
(1983) to 87% (1987). Cool weather before bud opening of the earliest clones
delayed and compressed the breeding period and resulted in a greater percentage
of trees having synchronous periods of pollen release and receptive seed strobili. Length of breeding season among years averaged 20
days and ranged from 16 to 27 days. Differences in phenology
significantly affected the breeding system because the overall breeding period
of the orchard clones exceeded the 8-day receptive period of individual clones
by two or three times, and often prohibited or limited potential outcrossing between the earliest and latest clones. Outcrossing was greatest in clones with intermediate phenology and least in the earliest clones. The breeding
system appears to be an almost continuous series of overlapping breeding
subpopulations. Each year's breeding subpopulations were different from those
of other years because of (1) large shifts in rank order of bud opening by 10
to 20% of the clones and (2) differences in the length of breeding season.
Average temperature during March was linearly associated with time of floral
bud opening. Geneticists may be able to use average temperature of the 4-week
periods prior to opening of the earliest floral buds as a tool to identify seed
crops formed during years with compressed breeding seasons. Such seed crops are
potentially more diverse than seed crops produced during years with extended
breeding seasons.
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11. Copes, D.L. 1999. Breeding graft-compatible Douglas-fir rootstocks (Pseudotsuga menziesii (MIRB.)
FRANCO). Silvae-Genetica 48(3/4): 188-193.
Keywords: genetic tree improvement
tree
grafting
tree/stand
protection
growth
tree
phenology
tree/stand
health
genetic
relationships
Abstract: A study
encompassing 24 years was conducted to determine if a breeding programme could produce highly graft-compatible rootstocks
for P. menziesii. A total of 27 trees of apparent
high graft compatibility were selected and crossed to produce 226
control-pollinated families. Seedlings were grown, field planted and grafted
with test scions. Graft unions from field tests were evaluated anatomically for
internal symptoms of incompatibility. Average compatibility of progeny from the
226 crosses was 90.6%, compared with 65% in native populations. Breeding values
were calculated for each parent by the best linear prediction (BLP) procedure.
Average compatibility resulting from crossing among the top 10 parents was
estimated by breeding values as 95.4%. Field-test results of progeny from 34
crosses among the 10 most compatible parents showed 96% compatibility. In
addition to field-tests for graft compatibility, nursery tests of seedlings
from 124 crosses were evaluated for second-year vegetative bud flush and
seedling height. It was possible, while maintaining adequately high levels of
graft compatibility, to breed both for resistance to spring frost damage and
for increased seedling height.
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12. Edwards, D.G.W. and Y.A. El-Kassaby. 1995. Douglas-fir genotypic response to seed
stratification. Seed-Science-and-Technology 23(3): 771-778.
Keywords: seed orchard management
reproduction
genetic relationships
Abstract: Douglas
fir (Pseudotsuga menziesii)
responses to stratification duration were studied using wind-pollinated seeds
from 15 seed-orchard clones, collected from a low elevation Douglas fir seed
orchard in Saanichton, British Columbia, Canada. Germinative parameters (germination
capacity, peak value, germination value, and germination rate and speed) were
evaluated in response to four stratification periods (0, 3, 5, and 7 weeks).
Significant differences among germinative parameters
were observed indicating that the five-week stratification period represents
the most appropriate treatment in minimizing variation caused by genetic
differences. The results indicate that the International Seed Testing
Association (ISTA) rules, which focus only on germination capacity, do not
provide an adequate expression of seedlot dormancy,
and since the rules are aimed at bulked seedlots,
genetic differences, which can be large in heterogeneous forest tree seeds, are
hidden. The results also demonstrate that extended stratification not only
reduces the time in which seedlings become established, but also reduces
seedling-emergence variation among parental lines.
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13. El Kassaby,
Y.A. 1995. Evaluation of the tree-improvement delivery system: factors
affecting genetic potential. Tree Physiology 15:545-550.
Keywords: genetic tree improvement
nursery
operations
seed
orchard management
genetic
relationships
reproduction
Abstract: Possible
causes of the genetic erosion that occurs during the fragmented phases of the
tree-improvement delivery system (a term used for the domestication process in
forest trees) are reviewed. The impacts of intentional and unintentional
directional selection during phenotypic selection, seed production (with its
associated reproductive-phenology asynchrony,
fecundity differential and varying propensity to inbreeding), seed processing
and storage, and seedling production are evaluated. Allozyme
analysis data were used to compare heterozygosity of
first-generation seed orchards of western red cedar (Thuja
plicata), Sitka spruce (Picea sitchensis) and Douglas fir (Pseudotsuga
menziesii) with that of their corresponding natural
populations. In general, genetic diversity and heterozygosity
parameters of seed orchards are higher or similar to those observed in their
natural-population counterparts. However, parental contribution to the
resultant seed orchard seed crops is consistently asymmetrical, and this is a
major cause of genetic erosion. In most cases, less than 20% of an orchard's
clones contribute 80% of the cone crop, thus reducing the effective population
size. Because seed germination of coniferous tree species is under strong
maternal genetic control, the combined effects of differences in reproductive
output and germination, as well as of management practices (e.g., simulated
long-term storage of seed showed that loss of viability during storage is
genotype specific), cause unintentional directional selection during seedling
production. This review confirms the need for genetic monitoring of each phase
of the tree-improvement delivery system, so that practical solutions can be
developed to alleviate genetic erosion.
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14. El Kassaby,
Y.A. 2000.
Representation of Douglas-fir and western hemlock families in seedling crops as
affected by seed biology and nursery crop management practices. Forest Genetics 7(4): 305-315.
Keywords: genetic tree improvement
nursery
operations
genetic
relationships
tree/stand
health
reproduction
Abstract: The
impact of container-nursery management practices on the genetic representation
of seedling crops of Douglas fir (Pseudotsuga menziesii) and western hemlock (Tsuga
heterophylla) were evaluated. Two experiments, one
for each species, were conducted in British Columbia, Canada, to determine the cumulative effects of seed-donor
variation on germination parameters (percent and speed) and their interaction
with container-nursery practices of thinning and culling on the genetic
representation of each seed-donor in the resultant seedling crops. The
experimental work was conducted on seedlots that were
represented with equal contribution of seeds from 15 seed orchard parents (families).
In each experiment, a total of 25 920 seeds were sown in four different
arrangements to compare the crop development under single-, two-, and
three-seeds per cavity (seeds within cavity were selected randomly among the 15
families) and family blocks (seeds within block belonged to one family). This
experimental design allowed determination of inter- and intra-family
competition. Within each experiment, a total of 15 015 cavities were used and
the identity of every seed within every cavity within each arrangement was
maintained throughout the study. Families were compared based on: (1) changes
in their rank order from seedling emergence (germination) to post-thinning and
post-culling status, and (2) relative performance of each family from seed contribution
to seedling production. Changes were observed in both assessments (i.e., rank
and relative contribution). Path analysis was used to determine the percent
contribution of each factor to seedling production. It was determined that
seedling germination, germinant thinning, and seedling culling all affected
seedling production, indicating the presence of several consecutive
unintentional bottlenecks in the process. Family sowing with culling standards
that recognize the growth differences among families in the nursery and single
seed sowing after understanding the inter-/intra-family competition are
recommended for seedling production to maintain seedling-crop family
representation.
OSU
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15. El Kassaby,
Y.A. and A. Benowicz. 2000. Effects of commercial thinning on genetic, plant
species and structural diversity in second growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands. Forest-Genetics 7(3): 193-203.
Keywords: thinning
commercial thinning
genetic relationships
Abstract: The impact
of commercial thinning on biodiversity was studied in two Douglas-fir (Pseudotsuga menziesii)
plantations, Weeks Lake (WL) and Fairservice Creek
(FC) located on southern Vancouver Island, British Columbia, Canada. The age of the stands at thinning was 53 and 70 years for
FC and WL, respectively. Other tree species were also present in both sites due
to natural regeneration. Biodiversity was evaluated before and after commercial
thinning with respect to tree species composition/abundance, tree species
genetic diversity assessed by allozyme analysis and
stand structural diversity represented by the diameter class (5-cm)
distribution. In addition, understorey plant species
diversity was monitored in WL and FC for 4 and 5 years following thinning,
respectively. Tree species composition changed in both plantations in a similar
fashion as the proportion of Douglas-fir increased at the expense of all other
tree species. Stand structural diversity was simplified due to the decreased
number of trees in small diameter classes. These results were expected since
the commercial thinning was conducted to promote the growth of Douglas-fir.
Genetic diversity parameters (average number of alleles per locus, percent
polymorphic loci and expected heterozygosities) did
not differ significantly before and after thinning; however, thinning resulted
in a loss of 8 and 7 alleles across species for FC and WL, respectively. Most
of the allelic loss occurred in the naturally regenerated species (93%). This
allelic loss represents 7 and 6% of the total alleles present in FC and WL,
respectively. Thus, only one allele was lost from the crop tree in the FC
plantation. Understorey vegetation species richness
decreased the year following commercial thinning and then consistently increased
over time in both plantations. A total of 17 and 9 new species colonized FC and
WL, respectively. One species was replaced in each plantation. In FC, diversity
of the understorey plant community based on the Shannon diversity index (H) changed in an increasing linear trend
that corresponded to the increase in species richness. On the other hand, H in
WL remained stable. Species evenness (H/Hmax) did not
change in WL and FC over the course of study except for seasonal fluctuations.
Rare species diversity increased over time in both plantations.
OSU
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16. El Kassaby,
Y.A., K. Chaisurisri, D.G.W. Edwards and D.W. Taylor. 1993. Genetic control of germination parameters of
Douglas-fir, Sitka spruce, western redcedar, and
yellow-cedar and its impact on container nursery production. In
Dormancy and barriers to germination. Proceedings of an
international symposium of IUFRO Project Group P2.04-00 (Seed problems),
Pacific Forestry Centre, Victoria, British Columbia, Canada.
Ed. D.G.W. Edwards. pp. 37-42.
Keywords: genetic tree improvement
nursery
operations
genetic
relationships
reproduction
Abstract: The
genetic control of germination parameters (germination capacity, peak value,
and germination value) in Douglas-fir (Psuedotsuga menziesii (Mirb.) Franco), Sitka spruce (Picea
sitchensis (Bong.) Carr.), western redcedar (Thuja plicata Donn), and yellow-cedar (Chamaecyparis nootkatensis (D.Don) Spach.) was studied using
wind-pollinated seeds collected from several seed orchards. The extent of
genetic control over rhese parameters was assessed
through the determination of broad-sense heritabilities.
The impact of genetic control of these parameters on the expected genetic
diversity of container nursery seedling crops is evaluated.
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17. El Kassaby, Y.A. and C. Cook. 1994. Female reproductive energy and reproductive success in a Douglas-fir seed orchard and its impact on genetic diversity. Silvae-Genetica 43(4): 243-246.
Keywords: genetic tree improvement
genetic relationships
reproduction
Abstract: The
relationship between reproductive energy and reproductive success and its
impact on clonal female gamete contribution were
studied in a clonal Pseudotsuga
menziesii seed orchard. The effect of among- vs.
within-clonal variation on seed-cone crop (energy)
and filled-seed yield (success) was determined by partitioning their respective
variance components. Clonal gametic
representations were expressed using Griffin's [Australian Forest Research (1982) 12, 295-302]
parental-balance curves and Crow and Kimura's [An introduction to population
genetic theory (1970) New York, USA; Harper and Row Publishers] effective population number.
Seed-cone and filled-seed yields produced similar parental-balance curves and
female effective population numbers. Although similar parental-balance curves
and female effective population numbers were produced, the actual clonal gametic representation
differed when the contribution of any set of specific clones were considered.
It was concluded that parental-balance curves and female effective population
numbers provide a static description of the genetic representation and do not
illustrate the dynamics of clonal reproductive
outputs.
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18. El Kassaby,
Y.A. and R. Davidson.
1990. Impact of crop management practices on the seed crop genetic quality in a
Douglas-fir seed orchard. Silvae-Genetica 39(5-6):
230-237.
Keywords: genetic tree improvement
seed
orchard management
genetic
relationships
Abstract: The
impact of 2 crop management practices, supplemental-mass-pollination (SMP) and
overhead cooling, on levels of pollen contamination and outcrossing
was assessed in a 13-year-old seedling Douglas fir (Pseudotsuga
menziesii) seed orchard with the aid of 6 allozyme loci. A 2 x 2 factorial arrangement of SMP/no SMP
and cooling/no cooling was applied to 4 genetically similar blocks of trees.
The 4 treatment combinations used were spatially and temporally isolated by
buffer blocks and 9-day reproductive bud phenology
delay, respectively. The study led to the following conclusions: (1) no
contamination was observed when cooling and/or SMP was used, (2) no inbreeding
was observed when cooling and SMP were used concurrently and (3) SMP was
effective in reducing consanguineous mating, but not to the level achieved by
cooling and SMP combined. In addition, the results obtained from the control
block (i.e. no cooling and no SMP) indicated that (1) isolation zones are
effective in reducing contamination, and (2) randomization of trees within seed
orchard blocks is associated with a high outcrossing
rate.
OSU
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Non-OSU Link
19. El Kassaby,
Y.A. and Y.S. Park. 1993. Genetic variation and correlation in growth,
biomass, and phenology of Douglas-fir diallel progeny at different spacings.
Silvae-Genetica 42(6): 289-297.
Keywords: genetic tree improvement
nursery
operations
genetic
relationships
growth
carbon
allocation
tree
phenology
Abstract: Parents
of coastal Douglas fir (Pseudotsuga menziesii) selected from natural stands on sites ranging
from 0 to 450 m altitude on Vancouver Island and in southeastern British Columbia were crossed and the resulting 104 full-sib families
evaluated for 3 years after germination. The full-sib families were produced by
a disconnected diallel mating scheme, consisting of 7
sets of 6-parent partial diallels, grown under 2
spacing treatments in a nursery. The objectives of the study were to determine
the extent of genetic control of growth traits, biomass distribution and
allocation strategies, and vegetative phenology.
Spacing had a significant effect on 6 of the 11 traits studied. Significant GCA
variance was found for all traits except 1-year height. Individual tree
narrow-sense heritability varied from 0.06 to 0.69 for root dry weight and
vegetative phenology, respectively. Spacing x family
interaction variance was significant for only 2 traits. Two harvest indices,
based on total and above-ground dry weights, were used to assess dry matter
allocation strategy and to explore potential usefulness in tree breeding. Both
indices had similar heritability estimates and their genetic correlation was
high (0.91), indicating that use of an index based on above ground dry weight
is a good surrogate for that based on total dry weight. Genetic correlations
among growth and biomass traits were generally high, while those correlations
with the harvest indices were variable.
OSU Link
Non-OSU Link
20. El Kassaby,
Y.A., J. Parkinson and W.J.B. Devitt. 1986. The effect of crown segment on the mating system in
a Douglas-fir (Pseudotsuga menziesii
(Mirb.) Franco) seed orchard.
Silvae-Genetica 35(4): 149-155.
Keywords: genetic tree improvement
seed
orchard management
genetic
relationships
reproduction
Abstract: The
mating system in a mixed clonal/seedling Douglas fir
seed orchard was studied by analysing 6 polymorphic allozyme loci. Trees were subjected to cooling treatment to
retard bud development and compact the pollination period. The outcrossing rates of upper and lower crown levels and
northern and southern crown aspects were estimated and compared for clonal and seedling material separately using single and multilocus methods. Single locus estimates of outcrossing rate ranged from 0.645 to 0.999 and were
significantly heterogeneous. No significant differences between the multilocus estimates were observed between crown levels or
aspects for either the clonal or seedling material.
For all comparisons, the unweighted or weighted
single locus means were lower than those obtained by the multilocus
method, indicating the presence of other types of consanguineous mating in
addition to selfing. In general, higher outcrossing rates were observed in the clonal
trees than in those derived from seedlings. The implications of these results
for seed orchard management are discussed.
OSU
Link
Non-OSU Link
21. El Kassaby,
Y.A. and K. Ritland. 1986. The relation of outcrossing
and contamination to reproductive phenology and
supplemental mass pollination in a Douglas-fir seed orchard. Silvae-Genetica 35(5/6): 240-244.
Keywords: genetic tree improvement
seed
orchard management
tree
phenology
genetic
relationships
economics
reproduction
Abstract: A study
was made using allozyme markers of outcrossing and contamination rates in relation to
reproductive phenology and supplemental mass
pollination in a Douglas fir seed orchard in British Columbia, Canada. Supplemental mass pollination was applied only to the
intermediate reproductive phenology class, which
showed a high outcrossing rate and no contamination.
Both early and late reproductive phenology classes
showed significant contamination, but the outcrossing
rate for the former was significantly higher than for the latter. These results
show that interpretation of seed crop genetic quality based on outcrossing alone could be misleading. The rate and source
of contamination, reproductive phenology and crop
size should also be considered. The practicability and economics of
supplemental mass pollination in avoiding both selfing
and contamination are discussed. It was concluded that waterspray
cooling and/or supplemental mass pollination of early and late reproductive phenology classes in moderate or good cone-crop years would
be an effective management practice. The option of aborting small cone crops in
mature orchards is also discussed.
OSU
Link
Non-OSU Link
22. El Kassaby,
Y.A. and A.J. Thomson.
1996. Parental rank changes associated with seed biology and nursery practices
in Douglas-fir. Forest Science 42:228-235.
Keywords: genetic tree improvement
nursery
operations
reproduction
genetic
relationships
tree/stand
health
Abstract: The
impact of container-nursery management practices on the genetic composition of
seedling crops was evaluated in an experimental study in a seed orchard in British Columbia. The study was designed to determine the cumulative
effects of: (1) differences in parental reproductive output in bulk seedlots; (2) parental variation in germination parameters
(percentage and speed); and (3) the interaction of these parameters with
container-nursery practices of thinning and culling, and their effect on the
genetic representation of parents in the resultant seedling crops. Results from
the experimental study were compared with predictions of a stochastic
simulation designed to estimate the consequences of differential parental seed
contribution, and seed germination percentage and germination speed on
indicators of crop performance. The experimental study was conducted on a
Douglas-fir (Pseudotsuga menziesii)
bulk seedlot that was representative of the
differential seed contributions from 19 seed orchard parents. The nursery study
included a total of 42 000 seeds. Seeds were sown at three seeds per cavity.
Within the 14 000 cavities used, the identity of every seed was maintained
throughout the study. Comparisons of parents were made based on: (1) changes in
their rank order from sowing to postthinning and postculling status; and (2) relative performance from seed
contribution to seedling production. Changes were observed in both assessments.
Path analysis was used to determine the percentage contribution of each factor
to seedling production. It was determined that germination, thinning, and
culling contributed 66, 20, and 14%, respectively, to seedling production,
indicating the presence of three consecutive bottlenecks in the process. Single
seed or individual family sowing in the nursery was recommended for seedling
production to maintain genetic diversity.
OSU
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Link
23. Fashler, A.M.K. and Y.A. El-Kassaby.
1987. The effect of water spray cooling treatment on
reproductive phenology in a Douglas-fir seed orchard.
Silvae-Genetica 36(5-6): 245-249.
Keywords: genetic tree improvement
seed
orchard management
tree/stand
protection
genetic
relationships
reproduction
tree/stand
health
Abstract: The
effectiveness of reproductive bud cooling on genetic efficiency in a Douglas
fir seed orchard in British Columbia, Canada, was tested by comparing the reproductive bud phenology in 3 cooled and 3 uncooled
years. The cooling system was found to affect 2 major elements affecting seed
orchard genetic efficiency, namely pollen contamination levels and panmictic equilibrium, as well as insect infestation, frost
damage, seed yield and management effectiveness. Based on these results, a
permanent irrigation/cooling system is recommended for
Douglas fir seed orchards.
OSU
Link
Non-OSU Link
24. Jermstad,
K.D., D.L. Bassoni, N.C. Wheeler, T.S. Anekonda, S.N. Aitken, W.T. Adams
and D.B. Neale. 2001b. Mapping of
quantitative trait loci controlling adaptive traits in coastal Douglas-fir.
II. Spring and fall cold-hardiness. Theoretical-and-Applied-Genetics 102(8):
1152-1158.
Keywords: genetic tree improvement
tree/stand
protection
genetic
relationships
tree
physiology
tree
phenology
Abstract: Quantitative
trait loci (QTLs) affecting fall and spring cold
hardiness (cold resistance) were identified in a three-generation outbred pedigree of coastal Douglas-fir (Pseudotsuga meniziesii var. menziesii [Pseudotsuga menziesii]) in a field experiment conducted in Washington
and Oregon, USA, during 1996-97. Eleven QTLs
controlling fall cold hardiness were detected on four linkage groups, and 15 QTLs controlling spring cold hardiness were detected on
four linkage groups. Only one linkage group contained QTLs
for both spring and fall cold hardiness, and these QTLs
tended to map in close proximity to one another. Several QTLs
were associated with hardiness in all three shoot tissues assayed in the
spring, supporting previous reports that there is synchronization of plant
tissues during de-acclimatization. For fall cold hardiness, co-location of QTLs was not observed for the different tissues assayed,
which was consistent with previous reports of less synchronization of hardening
in the fall. In several cases, QTLs for spring or
fall cold hardiness mapped to the same location as QTLs
controlling spring bud flush. QTL estimations, relative magnitudes of heritabilities, and genetic correlations based on clonal data in this single full-sib family, supports
conclusions about the genetic control and relationships among cold hardiness
traits observed in population samples of Douglas-fir in previous studies.
OSU Link
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25. Johnson, G.R. 1997. Site-to-site
genetic correlations and their implications on breeding zone size and optimum
number of progeny test sites for coastal Douglas-fir. Silvae-Genetica
46(5): 280-285.
Keywords: genetic tree improvement
genetic
relationships
Abstract: Type B
genetic correlations were used to examine the relationship among geographic
differences between sites and their site-to-site genetic (Type B) correlations.
Examination of six local breeding zones in Oregon indicated that breeding zones were, for the most part, not
too large because few environmental variables were correlated with Type B
genetic correlations. The data also were used to examine expected gains from
using combinations of sites in selection indices. Even though additional sites
always increased the expected genetic gain, the marginal increase was only
minimal if 3 or 4 sites were already in the index. The trend was consistent
over all 6 breeding zones.
OSU
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26. Johnson, G.R. 2002. Genetic
variation in tolerance of Douglas fir to Swiss needle cast as assessed by
symptom expression. Silvae-Genetica 51(2/3): 80-86.
Keywords: genetic tree improvement
tree/stand
protection
tree/stand
health
growth
genetic
relationships
Abstract: The
incidence of Swiss needle cast (caused by Phaeocryptopus
gaeumannii) on Douglas fir (Pseudotsuga menziesii) has increased significantly in recent years on
the Oregon coast. Genetic variation in symptoms of disease infection,
as measured by foliage traits, was assessed in two series of progeny trials to
determine whether these "crown health" indicators were under genetic
control and correlated with tolerance (tolerance being continued growth in the
presence of high disease pressure). Foliage traits generally had lower heritabilities than growth traits and were usually
correlated with diameter growth. Foliage traits of crown density and colour appeared to be reasonable indicators of disease
tolerance. In the absence of basal area data, assessing crown density and colour can help screen for families that show tolerance to
the disease.
OSU
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Non-OSU Link
27. Johnson, G.R., R.A. Sniezko and N.L. Mandel. 1997. Age trends in Douglas-fir
genetic parameters and implications for optimum selection age. Silvae-Genetica 46(6): 349-358.
Keywords: genetic tree improvement
growth
genetic
relationships
Abstract: Trends
in genetic variation in Douglas fir (Pseudotsuga menziesii) were examined over 51 progeny test sites
throughout western Oregon. Narrow sense heritabilities for
height and diameter showed an increasing trend to age 25, the oldest age
examined. Before age 10, height heritabilities were
relatively unstable. Type B site-site genetic correlations increased slowly
with age for height and remained relatively stable for diameter. Age-age
correlations were used to develop an equation to predict age-age correlations
by using the log of the age ratios (LAR). Optimum selection age was calculated
for a 60-year rotation by using two measures of efficiency: gain per year and
discounted gain. The optimum selection age for height tended to be 2 to 3 years
earlier than for diameter. Gain per year was maximized at age 10 for height and
age 13 for diameter.
OSU
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Non-OSU Link
28. Johnson, R. 1998. Breeding design considerations for coastal Douglas-fir. Pacific-Northwest-Research-Station, USDA-Forest-Service
General-Technical-Report PNW-GTR-411. iii + 34
p.
Keywords: genetic tree improvement
seed
orchard management
genetic
relationships
Abstract: The
basic principles of designing forest tree breeding programmes
are reviewed for Douglas fir (Pseudotsuga menziesii) in the Pacific Northwest (USA). Breeding populations
are discussed given current and future breeding zone sizes and seed orchard
designs. Seed orchard composition is discussed for potential genetic gain and
maintaining genetic diversity in the forest. Mating and field testing designs
are described and compared. Recommendations of the Breeding Zone Evaluation and
Restructuring Cooperatives Working Group of the Northwest Tree Improvement
Cooperative are presented.
OSU
Link
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29. Kaya, Z. 1992. The effects of test
environments on estimation of genetic parameters for seedling traits in
2-year-old Douglas-fir. Scandinavian-Journal-of-Forest-Research 7(3):
287-296.
Keywords: genetic tree improvement
nursery
operations
genetic
relationships
growth
tree
phenology
Abstract: The
effects of test environments (dry versus wet) on the estimation of genetic
parameters in seedling traits were studied in 160 open-pollinated families of
Douglas fir (Pseudotsuga menziesii)
from southwestern Oregon. Seedlings from four populations were grown in two test
nursery environments between which a water potential difference of -9 bars was
created over two growing seasons, by withholding water for 4 and 8 wk,
respectively. Estimated genetic variances in most growth and phenology traits were considerably higher for seedlings
grown in the wet environment than for those in the dry. Estimated genetic
correlations between the same traits measured in different test environments
indicated that most seedling traits studied for two growing seasons were
genetically stable in both environments, suggesting that genotype environment
interaction in these traits are weak. However, it is emphasized that the effect
of test environment on estimation of genetic parameters in seedling traits,
especially in adaptive seedling traits, should be evaluated very carefully when
early evaluation of genetic entries is practised in
Douglas-fir, since these traits (budburst timing, lammas growth and free growth) appear to be plastic
in character.
OSU
Link
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Link
30. Kaya,
Z. 1993. Genetic variation in shoot growth components and
their correlations in Pseudotsuga menziesii
var. menziesii seedlings.
Scandinavian-Journal-of-Forest-Research 8(1): 1-7.
Keywords: genetic tree improvement
genetic
relationships
growth
Abstract: Stem-unit
measurements could be useful for early selection if these dimensions were
highly heritable and strongly correlated with traits of commercial interest,
such as height growth. Height increments and the number and length of stem
segments were measured in the first and second growth period in predetermined
and free growth of Douglas-fir (Pseudotsuga menziesii var. menziesii)
seedlings from 40 families in each of 2 populations from southwestern Oregon, USA. Populations, or families in
populations, exhibited genetic variation in all traits except number of stem
units in predetermined growth. Heritabilities for
stem-unit measurements were higher than those for height increment in the first
growing season, but not in the second. Correlations among measurements of stem
units and height increments were only moderate (generally <0.70). It is
concluded that stem units are not likely to be better measurements of height in
early selection of Douglas-fir than are measurements of either predetermined or
free growth.
OSU
Link
Non-OSU
Link
31. Kaya, Z., R.K. Campbell and W.T. Adams. 1989. Correlated
responses of height increment and components of increment in 2-year-old Douglas
fir. Canadian-Journal-of-Forest-Research 19(9): 1124-1130.
Keywords: genetic tree improvement
tree
phenology
growth
genetic
relationships
Abstract: The
consequences for growth and phenology of early
selection for height or its growth components were evaluated in 160
open-pollinated families of Douglas fir (Pseudotsuga menziesii) from SW Oregon. Seedlings from 2 inland and 2 coastal populations (40
families each) were grown for 2 growing seasons in a 'moist' and 'dry' nursery
environment. Predicted response to selection suggests that risk of low
juvenile-mature correlation and maladaptation with
early selection would be less in the inland than in the coastal region. Early
bud set in the 1st yr was genetically correlated with larger overwintering buds in seedlings from both inland and
coastal regions. These larger buds yielded a large increment of predetermined
growth in the 2nd yr, followed by little or no free growth and early bud set.
Seedlings with late bud set in the 1st yr had the converse pattern. Inland
seedlings set buds much earlier on av. than coastal seedlings,
hence seedlings from the 2 regions had different growth patterns. Risks that
can attend early selection for ht. generally would be decreased in both regions
by selecting for predetermined growth, but several qualifications are discussed.
OSU
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Link
32. Kimball, B.A., G.R. Johnson, D.L.
Nolte and D.L. Griffin. 1999. An examination of the genetic control of
Douglas-fir vascular tissue phytochemicals:
implications for black bear foraging. Forest-Ecology-and-Management 123(2/3):
245-251.
Keywords: genetic tree improvement
tree/stand
protection
growth
tree
physiology
genetic
relationships
Abstract: Silvicultural
practices can influence black bear (Ursus americanus) foraging preferences for Douglas fir (Pseudotsuga menziesii)
cambial-zone vascular tissues, but little is known about the role of genetics.
To study the impact of genetic selection, vascular tissue samples were
collected from Douglas fir trees in 6 half-sib families from 5 different sites
in north central Oregon. Four replications of 3-tree non-contiguous plots were
sampled at each site to examine inter-and intra-site variation. Tree growth was
measured as tree diameter at breast height, and the absolute concentrations of
26 different terpenoids were determined by gas
chromatography/flame ionization detection from ethyl acetate extracts. The
simple carbohydrates fructose, glucose, and sucrose, and the phenolic glycoside coniferin were
quantified using anion-exchange chromatography with pulsed amperometric
detection. Cluster analysis was used to reduce the number of variables used in
analyses of variance. Results for the families studied here indicate that tree
growth and some terpenoids were under some level of
genetic control. Furthermore, allocation of constitutive terpenoids
in vascular tissues was not at the expense of tree growth. The sugars present
in vascular tissue were affected by environment (site) and genetics (family)
and their interaction.
OSU
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Link
33. King, J.N., F.C. Yeh and J.C.H. Heaman. 1988.
Selection of growth and yield traits in controlled crosses of coastal
Douglas-fir. Silvae-Genetica 37(3-4): 158-164.
Keywords: genetic tree improvement
growth
genetic
relationships
Abstract: Analysis
of variance of several yield traits including height, height increment,
diameter and volume in a full-sib progeny test of Douglas fir (Pseudotsuga menziesii) on 2 sites
in British
Columbia revealed significant amounts of additive genetic variance
but small and non-significant amounts of dominance genetic variance. Individual
tree heritabilities were between 0.08 and 0.16 for
growth traits and family heritabilities were between
0.55 and 0.73. Acceptable gains were predicted with progeny test re-selection
(10% volume gain per unit selection intensity). Age 6 height
was an effective selection trait, and correlated well with age 12 volume,
giving 70% relative efficiency for family selection. Age 12 height measurement and height increment between 10 and 12 did not
express significant genetic differences on the individual site analyses due in
part to uncontrolled within-plot variation. Diameter showed higher heritabilities and was less sensitive to inadequacies in
experimental design than the later height measurements. Index selection for
stem volume also demonstrated that diameter was the most effective growth trait
to predict the breeding value of parents for individual tree stem volumes.
OSU
Link
Non-OSU Link
34. Koshy,
M.P. and D.T. Lester. 1994. Genetic variation of wood shrinkage in a progeny
test of coastal Douglas-fir. Canadian-Journal-of-Forest-Research 24(8):
1734-1740.
Keywords: genetic tree improvement
wood
quality
genetic
relationships
Abstract: Directional
(longitudinal, tangential and radial) and volumetric wood shrinkage were analysed in 413 trees belonging to 48 full-sib families (4
paternal and 12 maternal parents) from an 18-year-old coastal Douglas fir (Pseudotsuga menziesii var. menziesii) progeny test in British Columbia. Six samples
per ring position (ring positions 1-5 from pith along stem radii), with two
rings in each ring position, were examined in a bolt taken at breast height
from the tree. Genetic effects were minimal for shrinkage, except for
longitudinal shrinkage at ring positions 1 and 2. High variability was
expressed among trees within plots and among samples with trees. The lack of
statistically significant family variance eliminates the possibility of
improving the shrinkage traits by genetic means, except for longitudinal
shrinkage in the first few rings. However, the high amount of variability
expressed between trees within plots and between samples within trees warrants
special attention for achieving uniformity of wood. Much of this variability
can be reduced by silvicultural methods.
OSU
Link
Non-OSU
Link
35. Koshy,
M.P. and D.T. Lester. 1997. Wood shrinkage and tree growth in coastal
Douglas-fir: implications of selection. Canadian-Journal-of-Forest-Research
27(1): 135-138.
Keywords: genetic tree improvement
wood
quality
growth
genetic
relationships
Abstract: Phenotypic
and genetic correlations of height and diameter at breast height with wood
shrinkage were studied in an 18-year-old Douglas fir (Pseudotsuga
menziesii) progeny trial in British Columbia. Correlations between growth traits and shrinkage were
minimal except for longitudinal shrinkage at rings close to the pith. In early
ring positions, there was a negative correlation between height and
longitudinal shrinkage, such that selection for increased height is expected to
reduce longitudinal shrinkage at ring positions closer to the pith. The results
support current efforts to increase wood production through genetic improvement
in growth rate by showing that current programmes of
selection for rapid early height growth will not result in significant increase
in wood shrinkage.
OSU
Link
Non-OSU Link
36. Li, P. and W.T. Adams. 1993.
Genetic control of bud phenology in pole-size trees
and seedlings of coastal Douglas-fir. Canadian-Journal-of-Forest-Research
23(6): 1043-1051.
Keywords: genetic tree improvement
genetic relationships
tree phenology
growth
Abstract: The
extent to which bud phenology is genetically
controlled and related to growth traits was examined in seedlings and pole-size
trees of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii). Data
on bud burst, bud set, and stem growth were collected from pole-size trees of
60 open-pollinated families growing in four plantations in Oregon, and from seedlings of 45 of these same families growing
in a bare-root trial in Washington, and greenhouse and transplant trials in Washington and Oregon. In both age-classes, bud burst was under moderate to
strong genetic control (hsuperscript 2<more or
=>0.44) and family breeding values were stable across test environments,
indicating that this trait could be readily altered in breeding programmes. Bud set was inherited strongly in pole-size
trees (hsuperscript 2=0.81) but weakly in seedlings (hsuperscript 2<less or =>0.30). Both bud burst and
bud set were positively correlated with growth in seedlings and pole-size
trees. Thus, selection for greater growth at either age-class is expected to
delay bud burst and bud set. An evaluation was made of the accuracy of two
alternatives for assessing bud burst phenology in
pole-size trees compared with the traditional method. It was shown that
bud-burst date on lateral branches can be used to rank accurately both
individuals and families for bud-burst date on less accessible leader shoots.
In addition, it was found that families can be ranked for mean bud-burst date
by the proportion of trees per family that have flushed on a given scoring day.
This method is only effective, however, when between
25 and 75% of all trees in the test have flushed at the time of scoring.
OSU
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37. Li, P. and W.T. Adams. 1994.
Genetic variation in cambial phenology of coastal
Douglas-fir. Canadian-Journal-of-Forest-Research 24(9): 1864-1870.
Keywords: genetic tree improvement
genetic relationships
tree phenology
growth
Abstract: The
objectives of this study were to (i) determine the
extent of genetic variation and genetic control of cambial phenology
in coastal Douglas fir (Pseudotsuga menziesii var. menziesii), (ii)
assess the degree to which cambial phenology is
genetically related to bud-burst timing, (iii) examine genetic relationships
between cambial phenology and growth traits, and (iv)
evaluate the potential for indirectly altering cambial phenology
in breeding programmes when selection is for stem
volume. Dates of diameter-growth initiation and cessation, and duration of
diameter growth (i.e., cambial phenology traits), as
well as diameter increment for the 1987 growing season (15-yr-old), were
estimated from cumulative diameter growth curves of individual trees of 60
open-pollinated families growing in one plantation in Oregon. Data on stem height
and diameter at breast height (d.b.h.), and date of
bud burst in 1987 were also collected. Dates of diameter-growth initiation and
cessation differed significantly among families, but had lower estimated
individual heritabilities (<less or =>0.23)
than date of bud burst (0.87). Weak genetic correlations between date of bud
burst and dates of diameter-growth initiation and cessation (range -0.09 to
0.26) indicate that timing of diameter growth cannot be reliably predicted from
observations of the more easily measured bud burst. Cambial phenology
traits were weakly correlated with 1987 diameter increment and moderately
correlated with 15-year d.b.h. and volume. Selection
of parents in this study for stem volume at age 15 and subsequent crosses among
them, would be expected to lead to earlier initiation of diameter growth in the
offspring, and possibly later cessation as well. The practical implications of
these indirect responses in terms of increased risk of frost damage are
unclear, since projected changes are small (i.e., a few days).
OSU
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38. Magnussen,
S. and F.C. Sorensen. 1991. Outliers in forest genetics trials: an example of
analysis with truncated data. Scandinavian-Journal-of-Forest-Research 6(3):
335-352.
Keywords: genetic tree improvement
genetic
relationships
Abstract:
Previously published data for distribution of height in a Douglas fir (Pseudotsuga menziesii) progeny
trial in the Oregon Cascades with open (wind) pollinated (OP) and control
pollinated (CP) progenies showed an excess of short trees, especially in OP
(inbred) progeny, compared with a normally distributed population. Short trees
had a disproportionate influence on variance components and heritability
estimates. Data truncation of potential outliers was carried out with varying
intensity in order to investigate its influence on genetic parameter estimates.
Truncation was done by either fixed threshold values or by a proportional
elimination of trees from below. Truncated data was analysed
either directly or subsequent to a maximum likelihood (ML) recovery of the
estimated means and variances of the expected completed samples. ML estimates
became increasingly stable as truncation proceeded into the main body of data.
Prior to data truncation, the estimated additive variance and heritability
estimates of the CP population were significantly greater than corresponding
estimates for the OP population. However, ML estimates obtained after a
proportional elimination of about 12% of the trees in each plot supported the
contention that there was no important difference in additive genetic variance
or heritability between OP and CP populations.
OSU
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39. Magnussen, S. and A.D. Yanchuk. 1994. Time
trends of predicted breeding values in selected crosses of coastal Douglas-fir
in British Columbia: a methodological study. Forest-Science 40(4): 663-685.
Keywords: genetic tree improvement
genetic
relationships
growth
Abstract:
Analytical techniques for estimating time trends and projections of breeding
values from sparse data, unbalanced mating designs and irregular assessments
periods are presented and discussed. Time trends (ages 4 to 23 yr) in genetic
parameters of tree heights in 14 full-sib and 4 half-sib Douglas fir (Pseudotsuga menziesii) crosses
among six male trees from Coastal British Columbia and six female trees from
Washington and Oregon planted on four test sites on Vancouver Island were
examined, and tentative projections of genetic gains were made. Annual height
estimates were derived by fitting splines to height
measures at ages 4, 7, 12, 18 and 23 yr. Genetic variances were derived from
direct computations of covariances among all possible
half-sib combinations; a method deemed superior to the conventional factorial
analysis. Irregular fluctuations in genetic parameter estimates vanished after
minor adjustments (<1.5%) of variance-covariance matrices with negative eigenvalues. Sites effects were highly significant, but
site-to-site correlations for pair-cross means were all nonsignificant.
Additive genetic control of height growth was weak to moderate (hsuperscript 2=0.1), but generally increasing with age. The
best genetic discrimination was observed on the more productive sites. A stable
ranking of full-sib family means was reached at age 7 yr on one site versus age
18 for the other sites. Trends in breeding values were described with a mixed
linear autoregressive time series model from which 10-yr projections were made.
Projections took into consideration both the error structure surrounding the
breeding values and the errors of the parameter estimates in the time series
model. Selection of the best parent out of six for breeding and deployment on a
single site type would generate an expected gain of about 2-5% in height growth
between ages 4 and 23 yr.
OSU
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Non-OSU
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40. Malavasi,
U.C. and D.A. Perry. 1993. Genetic variation in competitive ability of some shade-tolerant
and shade-intolerant Pacific Coast (USA) conifers.
Forest-Ecology-and-Management 56(1-4): 69-81.
Keywords: planting operations
genetic relationships
growth
Abstract:
Variability in growth response to stocking density and neighbour
composition was compared in Oregon among half-sibling families of four tree
species representing two pairs of shade-tolerant (ST) and shade-intolerant (SI)
species, each pair from the same life zone. The hypothesis was that the wider
regeneration niche of ST species, which can become established both in
disturbed areas and within closed forests, would produce greater genetic
variability among families than occurs in SI species, which establish primarily
in disturbed areas. Families of western hemlock (Tsuga
heterophylla - ST), coastal Douglas fir (Pseudotsuga menziesii - SI) and
Pacific silver fir (Abies amabilis
- ST) varied in their responses to stocking density, but those of noble fir (A.
procera - SI) did not. As hypothesized, the ST
species were significantly more variable than SI ones, a result consistent with
electrophoretic studies of ST and SI plants and
supportive of the hypothesis that at least a portion of genetic variability
contained within populations represents adaptation to variable environments.
OSU
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41. O'-Neill, G.A., W.T. Adams and S.N. Aitken.
2001. Quantitative genetics of spring and fall cold hardiness in seedlings from
two Oregon
populations of coastal Douglas-fir. Forest-Ecology-and-Management 149(1/3):
305-318.
Keywords: genetic
tree improvement
tree/stand protection
tree/stand health
genetic relationships
Abstract:
Genetics of autumn and spring cold hardiness were investigated in two
western Oregon (USA) breeding populations (Coast and Cascade
mountains) of Douglas-fir (Pseudotsuga
menziesii var. menziesii).
Seedlings from 40 open-pollinated families from each population were grown in
raised nursery beds and subjected to two soil moisture regimes (well-watered
and mild drought) to evaluate the influence of summer drought on ranking of
families for cold hardiness. Artificial freeze testing (AFT) of detached
shoots, followed by visual scoring of injury, was used to evaluate needle, stem
and bud cold hardiness on three dates in the autumn (September, October and
November) after the second growing season, and once in the following spring
(March). The Cascade population suffered significantly less cold injury than
the Coast population in autumn AFT. However, in spring AFT the Cascade
population was less cold hardy, although population differences were seldom
significant. Families within both breeding zones varied significantly in cold
hardiness, with mean estimates of individual heritabilities
greater in spring (hi2=0.57) than autumn (hi2=0.37), greater in the Coast
(hi2=0.52) than in the Cascade (hi2=0.42) population, and greater in the wet
(hi2=0.54) than in the dry moisture regime (hi2=0.40) (autumn means based on
October tests). A single test date seems adequate to assess autumn cold
hardiness, because estimated genetic correlations for cold injury between
autumn test dates were strong (rA=0.80). Genetic
correlations between spring and autumn cold injury, however, were moderately
negative (rB=-0.66 and
-0.21, Coast and Cascade, respectively), indicating that cold hardiness needs
to be managed as two traits (i.e. autumn and spring cold hardiness). Selection
for cold hardiness based on a single shoot tissue is expected to increase cold
hardiness in the other tissues as well, because genetic correlations between
tissues in cold injury were moderately-to-strongly positive in both autumn (rB=0.67)
and spring (rB=0.84). Seedlings grown under summer
drought incurred significantly less cold injury in the autumn than those that
were well-watered; nevertheless, strong genetic correlations in autumn cold
injury between moisture regimes (rB=0.91) indicate
that summer moisture conditions had little influence on family rankings for
autumn cold hardiness. Correlations of injury resulting from a natural frost
event in November of the first year with injury from AFT in the autumn of the
second year (rA=0.72 and 0.78 for needle and bud
injury, respectively) confirmed that AFT reliably predicts cold hardiness to
natural frost events.
OSU
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42. O'-Neill, G.A., S.N. Aitken and W.T.
Adams. 2000. Genetic selection for cold hardiness in coastal Douglas-fir
seedlings and saplings. Canadian-Journal-of-Forest-Research 30(11): 1799-1807.
Keywords: genetic
tree improvement
tree/stand protection
genetic relationships
tree phenology
Abstract:
Genetic control of cold hardiness in two-year-old seedlings in a
nursery in Oregon, USA, was compared with that in 7-year-old field saplings,
for 40 open-pollinated families in each of two low-altitude breeding populations
(Coast and Cascade) of coastal Douglas fir (Pseudotsuga
menziesii var. menziesii)
from western Oregon. The field trials were also in the Coast and Cascade
breeding zones of Oregon
(7 and 6 sites, respectively). In addition, the efficacy of bud phenology traits as predictors of cold hardiness at the two
stages was explored. Autumn and spring cold hardiness were
assessed using artificial freeze testing. Similar genetic control of cold
hardiness in seedlings and saplings is suggested by strong type-B genetic
correlations (rB) between the two ages for autumn and
spring cold injury traits (rB<more or =>0.78)
and by similar trends in individual tree heritability estimates (hi2), e.g.,
hi2 was greater in spring (mean 0.73) than in autumn (mean 0.36) and greater in
the Coast population (0.69) than in the Cascade population (0.40) at both ages.
Strong responses to direct selection are expected for spring cold hardiness at
both ages and for autumn cold hardiness in seedlings, even under mild selection
intensities. Similar heritabilities in seedlings and
saplings, and strong genetic correlations between ages for cold-hardiness
traits, ensure that selection at one age will produce similar gains at the
other age. Type-A genetic correlations (rA) between
autumn and spring cold hardiness were near zero in the Cascade population (0.08
and -0.14 at ages 2 and 7, respectively) but were moderate and negative in the
Coast population (-0.54 and -0.36, respectively). Bud-burst timing appears to
be a suitable surrogate to artificial freeze testing for assessing spring cold
hardiness in both seedlings and saplings, as is bud set timing for assessing
fall cold hardiness in seedlings, but bud set timing is a poor predictor of
fall cold hardiness in saplings.
OSU
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43. Riitters, K.H. and D.A. Perry. 1987.
Early genetic evaluation of open-pollinated Douglas-fir families.
Forest-Science 33(2): 577-582.
Keywords: genetic
tree improvement
genetic relationships
growth
tree phenology
Abstract:
A summary is given of experiments to determine the correlation of seed wt. and
growth and phenology of seedlings of 14 families in a
cold frame with ht. of saplings from earlier seed crops of the same families in
5 plantations at 9, 12 and 15 yr old. With some exceptions, correlations of
seedling variables with field ht. were poor. Highest correlations with 15-yr
ht. were for budset at 117 days, ht. and branching
index of seedlings. Seedling growth and phenology
values were generally poorly correlated with seed wt. Seedling/sapling
correlations, however, were related to seedling/seed wt. correlations.
Seedling/sapling correlations improved between 9 and 15 yr old.
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44. Schermann, N., W.T. Adams, S.N. Aitken and J.C. Bastien. 1997.
Genetic parameters of stem form traits in a 9-year-old coastal Douglas-fir
progeny test in Washington.
Silvae-Genetica 46(2/3): 166-170.
Keywords: genetic
tree improvement
growth
wood quality
genetic relationships
tree phenology
Abstract:
The genetic control of stem form traits was investigated in a
9-year-old progeny test comparing 80 open-pollinated families of Pseudotsuga menziesii, located in
a fertile Pacific coast site in Washington,
USA.
In addition to stem form traits (internode sinuosity,
and number of forks and ramicorns per tree), stem
volume (height and DBH), bud phenology (earliness of
budburst and budset), and occurrence of second
flushing on the leader shoot (9th growing season) were measured. Trees with at
least one fork or ramicorn were frequent (26% and
46%, respectively), as were trees with second flushing
(26%). Most of the trees exhibited sinuosity of limited magnitude. Due to
strong differences among family means and at least modest family heritabilities (0.35 to 0.66), all traits were found to be
amenable to genetic improvement. The estimated genetic correlation (rA) between numbers of forks and ramicorns
was relatively strong (0.54), and both forking defects traits exhibited similar
genetic associations with other traits. Forking defects were strongly and positively
associated with frequency of second flushing, a trait which in turn is
positively and moderately correlated with both DBH (0.32) and earliness of
budburst (0.39). These results are consistent with previous findings. Breeding
consequences for simultaneous improvement of both stem volume and form are
discussed.
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45. Schowalter, T.D. 1988. Tree breeding and
insects: effect of insects on the genetic diversity of Douglas-fir.
Northwest-Environmental-Journal 4(2): 346-347.
Keywords: seed
orchard management
nursery operations
tree/stand protection
tree/stand health
reproduction
genetic relationships
Abstract:
Two studies on the effects of insects on Douglas fir [Pseudotsuga menziesii] seed and
seedling production in Oregon
are summarized. In the first study, seed losses due to Douglas fir cone gall
midge [Cecidomyiidae] and Douglas fir seed chalcid [Megastigmus spermotrophus] were studied. It is suggested that
resistance to these pests may be a heritable trait and that tree position
within a stand can modify genetically-controlled susceptibility to insect
attack. The second study indicated that genetically-controlled susceptibility
of seedlings to attack by lygus bug [Lygus sp.] could be modified by their proximity to
alternative food plants.
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46. Schowalter, T.D. and M.I. Harverty. 1989. Influence of host genotype on Douglas-fir
seed losses to Contarinia oregonensis
(Diptera: Cecidomyiidae)
and Megastigmus spermotrophus
(Hymenoptera: Torymidae) in Western
Oregon. Environmental-Entomology 18(1): 94-97.
Keywords: genetic
tree improvement
seed orchard management
tree/stand protection
genetic relationships
tree/stand health
Abstract:
Seed losses due to the cecidomyiid Contarinia oregonensis and the chalcid Megastigmus spermotrophus were measured in a Douglas-fir (Pseudotsuga menziesii) clonal seed orchard and in a Douglas-fir progeny plantation
in western Oregon.
Seed losses due to both insects differed significantly among clones and among
the progeny of selected parental crosses. Seed loss differed more than 3 times
between least-infested and most-infested clones or progeny. Seed losses in the
progeny plantation indicated that resistance to these 2 insects is a heritable
trait, with greater resistance showing a tendency to dominate over lesser
resistance. Insect responses to host genotype may be modified by factors
associated with the position of the tree within the stand. Implications of
these results for tree improvement programmes and
seed orchard management are discussed.
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47. Schowalter, T.D., M.I. Haverty, S.A. Dombrosky and J.
Sexton. 1986. Response of Douglas-fir cone gall midge and Douglas-fir seed chalcid to host plant genotype. In Proceedings of the 2nd
Conference of the Cone and Seed Insects Working Party, Station de Zoologie Forestiere, Olivet,
France, September 3-5, 1986. Ed. A. Roques. pp.
217-223.
Keywords: genetic
tree improvement
seed orchard management
tree/stand protection
genetic relationships
tree/stand health
Abstract:
Seed losses due to 2 species of insects were measured from cones of 51
parental crosses (or families, distinct combinations of 6X11 parents) in a
12-year-old progeny plantation of Douglas fir (Pseudotsuga
menziesii) in western Oregon.
In 1983 and 1984, seed losses due to Contarinia oregonensis were significantly different among host
families. During 1984, 4 of 5 families with the highest midge damage (x=79%)
shared a common parent and 4 of 5 families with the lowest midge damage (43%)
shared a common parent. This indicates that resistance or susceptibility to the
cecidomyiid is probably heritable. Losses due to Megastigmus spermotrophus were
measured only in 1984 and were also significantly different among host
families. Insect responses to host genotype appeared to be influenced by the
position of the tree within the plantation, by the size of the cone crop and,
in the case of M. spermotrophus, by prior activity of
C. oregonensis.
48. Sorenson, F.C. and R.K. Campbell. 1993. Seed weight-seedling size
correlation in coastal Douglas-fir: genetic and environmental components. Canadian-Journal-of-Forest-Research
23(2): 275-285.
Keywords: genetic
tree improvement
growth
genetic relationships
Abstract:
The effect of seed weight of coastal Douglas fir (Pseudotsuga
menziesii var. menziesii)
on nursery seedling height was analysed in two
experiments. In the first experiment, 16 seeds per family from 111 families
were individually weighed and sown in the autumn. In the second experiment,
another group of 16 seeds were individually weighed and stratified and sown in
the spring. Four-tree non-contiguous family plots were randomly assigned to two
densities in two replications in each experiment. Date of emergence and
duration and rate of shoot elongation were determined over 2 years of growth.
Seedlings in the first experiment were unintentionally exposed to damaging
frost after emergence. Some seedlings in the second experiment suffered Lygus bud damage to the terminal shoot. Developmental
associations between seed weight, a maternally inherited trait, and seedling
height and its components were examined using sets of path analyses with and
without adjustments for planned and accidental treatment effects. Results
suggested both 'environmental' and 'genetic' contributions of seed weight to
seedling height. The weight (environmental) component, alone, decreased with
time. The genetic component, which was indicated by lack of direct effect of
seed weight on seedling height in the path analyses and by changing female:male variance ratios over
time, was quite stable across treatment effects. Because of the genetic
relation, seed weight adjustment is not recommended as a procedure for
increasing precision in early selection of coastal Douglas fir families.
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49. St-Clair, J.B. 1994a. Genetic variation in tree
structure and its relation to size in Douglas-fir. I. Biomass
partitioning, foliage efficiency, stem form, and wood density.
Canadian-Journal-of-Forest-Research 24(6): 1226-1235.
Keywords: genetic
tree improvement
genetic relationships
carbon allocation
wood quality
growth
Abstract:
Genetic variation and covariation among
traits of tree size (volume, basal area, diameter at breast height and height)
and structure were assessed in 1991 in an 18-year-old Douglas fir (Pseudotsuga menziesii var. menziesii) genetic test in the Coast Range of Oregon.
Considerable genetic variation was found in size, biomass partitioning and wood
density, and genetic gains may be expected from selection and breeding of
desirable genotypes. Estimates of heritability for partitioning traits,
including harvest index (the proportion of fixed carbon converted to stemwood), were particularly high. Foliage efficiency (stem
increment per unit leaf area) was correlated with harvest index and may
represent an alternative measure of partitioning to the stem. Estimates of
foliage efficiency where leaf area was estimated based on stem diameter or
sapwood area were unrelated to foliage efficiency where leaf area was measured
directly. Strong negative genetic correlations were found between harvest index
and stem size, and between wood density and stem size. Large trees were more
tapered than small trees. It is concluded that simultaneous genetic gain in
stem size and either harvest index or wood density would be difficult to
achieve.
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50. St-Clair, J.B. 1994b. Genetic variation in tree
structure and its relation to size in Douglas-fir. II. Crown form,
branch characters, and foliage characters. Canadian-Journal-of-Forest-Research
24(6): 1236-1247.
Keywords: genetic
tree improvement
carbon allocation
tree morphology
wood quality
genetic relationships
Abstract:
Genetic variation and covariation among traits of
tree size (volume, basal area, diameter at breast height and height) and
structure were assessed in 1991 in an 18-year-old Douglas fir (Pseudotsuga menziesii var. menziesii) genetic test in the Coast Range of Oregon.
Considerable genetic variation was found for relative crown width, stem
increment per crown projection area, leaf area and branch weight relative to
crown size, branch diameter and length adjusted for stem size, branch
stoutness, cross-sectional area of branches per crown length and needle size.
Little genetic variation was found for branch numbers per whorl, branch angle
and specific leaf area. At both the phenotypic and genetic level, large trees
growing in relatively small spaces had tall, narrow crowns, high leaf areas per
crown projection area or branch length, greater partitioning to leaves versus
branches, and stouter branches. Thus, large, efficient trees were those that
invested more in the photosynthetic machinery of leaf area and the branch
biomass necessary to support that leaf area, but distributed that leaf area
over a greater vertical distance. Unfortunately, these traits were also
associated with increased branchiness, and selection
for these traits would be accompanied by reductions in harvest index and wood
quality.
OSU
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51. St-Clair, J.B. and W.T. Adams. 1991a. Effects of seed weight and
rate of emergence on early growth of open-pollinated Douglas-fir families.
Forest-Science 37(4): 987-997.
Keywords: genetic
tree improvement
nursery operations
reproduction
genetic relationships
growth
Abstract:
Open-pollinated seeds were collected from 39 Douglas fir (Pseudotsuga menziesii var. menziesii) families in second-growth stands in the Coast
Range
of west-central Oregon
(150-500 m altitude) in autumn 1985. Seed weight, time of emergence, and three
measures of seedling size were recorded for each family in order to assess
family variation in seed weight and emergence, and the influence of these seed
traits on early growth. Seeds were dewinged, cleaned
and stored at 0 degrees C. In April 1986, seeds and germinants
were sown at a depth of 8 mm to test whether using germinants
minimized seed effects on early growth. To evaluate the effect of competition
on the relationships of seed weight and rate of emergence to seedling size,
individuals of families were planted in mixed-family blocks at close spacing
(4x4 cm), in single (pure) family blocks at close spacing (4x4 cm) and in mixed
family blocks at a wide, noncompetitive spacing (16x16 cm). Families differed
significantly in seed weight, total emergence percentage and rate of emergence.
However, correlations of seed weight to rate of emergence, and seed weight and
rate of emergence to seedling size, were not strong.
Using germinants was ineffective in diminishing seed
effects. Interfamily competition had a minor influence on enhancing the effect
of seed traits on seedling growth.
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52. St-Clair, J.B. and W.T. Adams. 1991b. Relative family performance
and variance structure of open-pollinated Douglas-fir seedlings grown in three
competitive environments. Theoretical-and-Applied-Genetics 81(4): 541-550.
Keywords: genetic
tree improvement
nursery operations
genetic relationships
growth
Abstract:
Open-pollinated Douglas fir (Pseudotsuga menziesii) var. menziesii
families were tested in 3 contrasting competitive environments to test the
hypothesis that relative performance as measured by total seedling dry weight
is dependent upon distance or genotype of neighbours.
The 3 environments included (1) a mixture of individuals from all families sown
at close spacing, (2) single (pure) family blocks sown at close spacing, and
(3) individuals from all families sown at a wide, non-competitive spacing.
Despite occasional large changes in rank between competitive environments and
only moderate correlations of family means between competitive environments,
the family x competitive environment interaction was non-significant.
Furthermore, families did not differ significantly in competitive ability or
density tolerance. The competitive environment in which seedlings were grown,
however, had a large effect on estimates of variance components, which in turn
led to large differences in estimates of heritability and genetic gain. Evaluation
of families in mixture resulted in the largest estimates of heritability, while
evaluation in pure family blocks resulted in the lowest. Analysis of correlated
response to selection indicated that testing and selection in mixture resulted
in the largest estimated gain, even if progeny of selected individuals are
subsequently grown in a pure or non-competitive environment.
OSU Link
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53. St-Clair, J.B. and W.T. Adams. 1993. Family composition of
Douglas-fir nursery stock as influenced by seed characters, mortality, and
culling practices. New-Forests 7(4): 319-329.
Keywords: genetic
tree improvement
reproduction
growth
genetic relationships
Abstract:
Changes in family composition during nursery production were evaluated
by following individual seeds and seedlings of 36 wind-pollinated Douglas fir (Pseudotsuga menziesii var. menziesii) families sown in mixture in two operational
nurseries in western Washington
and Oregon.
Families differed significantly in emergence (measured after 5 wk) and in
percentage of seedlings culled for being too small (at end of second growing
season: <4 mm stem diameter or <20 cm stem height). Filled seed
germination rates (tested in the laboratory) were not related to emergence
rates. Differences overall were small enough that family composition was
largely unaffected. Observed changes in family composition did not markedly
reduce genetic diversity and did not affect the genetic gain that may be
expected from an improved population. The plantable
nursery stock was, for the most part, representative of the composition of
families originally sown.
OSU
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54. Stoehr, M.U., B.L. Orvar,
T.M. Vo, J.R. Gawley, J.E. Webber and C.H. Newton. 1998. Application of a
chloroplast DNA marker in seed orchard management evaluations of Douglas-fir.
Canadian-Journal-of-Forest-Research 28(2): 187-195.
Keywords: genetic
tree improvement
genetic relationships
reproduction
Abstract:
Pollen contamination, supplemental mass pollination efficacies, and natural selfing were evaluated in a Douglas fir (Pseudotsuga menziesii) clonal-row seed orchard near Victoria,
British Columbia,
using a genetic marker on the paternally inherited chloroplast (cp) genome. A
primer pair for the polymerase chain reaction amplification of a variable
region on the cpDNA in Douglas fir was developed. The
amplified DNA product was highly variable in size, yielding 13 different haplotype bands from 20 orchard genotypes growing in the clonal-row seed orchard. Observed band sizes ranged from
859 to 1110 base pairs (bp). To estimate variation
levels in the orchard background pollen pool, 96 assayed genotypes from
surrounding stands gave rise to 36 different haplotypes,
ranging from 367 to 1119 bp in size, resulting in a
gene diversity estimate of 0.91. Most orchard clones' haplotypes
were also present in the background. After adjusting for the presence of
orchard-type haplotypes in the background,
contamination was found to be 40%. Natural selfing in
six individual clones ranged from 0 to 19% with an average of 6%. Supplemental
mass pollination efficacy was estimated to be 55%, ranging from 39 to 73%,
depending on the maternal clone and flowering phenology.
This DNA marker proved to be very useful in assessing seed orchard mating
dynamics and orchard management efficacies for Douglas fir.
OSU
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55. Stoehr, M.U., J.E. Webber and R.A.
Painter. 1994. Pollen contamination effects on progeny from an off-site
Douglas-fir seed orchard. Canadian-Journal-of-Forest-Research 24(10):
2113-2117.
Keywords: genetic
tree improvement
seed orchard management
growth
genetic relationships
reproduction
Abstract:
The effects of background pollen contamination were evaluated for first-year
height growth pattern of seedlings originating from a Douglas fir (Pseudotsuga menziesii)
coastal-interior transition zone seed orchard located on southern Vancouver
Island, British
Columbia. Pollen collected
from five stands surrounding the orchard (background pollen) and pollen from
five half-sib families of the seed orchard were applied to six individual trees
in the orchard. The resulting 60 seed lots were raised outdoors in a
coastal-climate nursery with five seed lots collected from wild stands of the
transition zone. Heights were measured at 10-day intervals during the growing
season. Final heights, maximum height growth rate and growth cessation were
subjected to analysis of variance. Growth rate and cessation were derived from
data fitted to the logistic growth curve using nonlinear regression analysis.
Seedlings sired by the background pollen had significantly greater final
heights and growth rates. There were no differences in orchard seedlings in
growth cessation probably because all seedlings were exposed to a blackout
treatment to force bud set in mid-August. The average final height of
wild-stand seedlings from the transition zone was 15% and 21% lower than that
of pure orchard seedlings and seedlings sired by the background pollen lots,
respectively. Standard deviations for measured traits were similar between
orchard seedlings sired by background pollen and orchard pollen. If pollen
contamination is not prevented, the faster growing seedlings sired by the
background pollen may be preferentially selected during culling in the nursery
and outplanted on sites to which they are maladapted.
OSU
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56. Stonecypher, R.W., R.F. Piesch, G.G. Helland, J.G. Chapman
and H.J. Reno. 1996. Results from genetic tests of selected parents of
Douglas-fir (Pseudotsuga menziesii
[Mirb.] Franco) in an applied tree
improvement program. Forest-Science-Monograph (32): 35.
Keywords: genetic
tree improvement
planting operations
growth
tree phenology
genetic relationships
Abstract:
Results from genetic tests, and genotype x environment interaction
studies in six low-elevation breeding zones of Weyerhaeuser Company's Western
Washington and Oregon Douglas fir (Pseudotsuga
menziesii) tree improvement programme
are summarized. Phenotypic selection in natural stands resulted in a 5%
improvement in juvenile height over nonselect seed
lots. Comparisons with nonselect sources, of
offspring from parents in the top 50% performers in tests, indicated a 10%
increase for the same trait. Seed produced in a 50% rogued
seed orchard is thus expected to provide improved planting stock with a gain of
10% in juvenile height growth. Several select parents are producing offspring
that are consistently performing in excess of 10% over nonselects.
Estimates of breeding zone, breeding zone by location, and family by location
interaction effects are small relative to family and planting location effects.
Tests of families established on environmentally diverse sites indicate a
striking lack of large family by planting location interaction. In tests
showing statistically significant interactions, such interactions are caused by
a relatively small number of families. Earlier budbreak
and a higher spring frost susceptibility of Oregon
sources established on Washington
sites were observed. It is concluded that allocation and utilization of select
families within Weyerhaeuser's Oregon
and Washington
ownership should not be constrained by the currently defined breeding zone
boundaries, but based on parental performance and stability for growth and
adaptive traits in general. It is suggested that the necessity for maintaining
separate breeding zones, within Washington
and Oregon,
in subsequent cycles of recurrent selection is questionable. Average individual
tree heritability, from 65 6-parent disconnected diallels,
is 0.13 for age 6 and age 8 height. Dominance genetic
variance is estimated to be one-half that of additive genetic variance for the
same traits.
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57. Temel, F. and W.T. Adams. 2000.
Persistence and age-age genetic correlations of stem defects in coastal
Douglas-fir (Pseudotsuga menziesii
var. menziesii (Mirb.)
Franco). Forest-Genetics 7(2): 145-153.
Keywords: genetic
tree improvement
genetic relationships
growth
wood quality
Abstract:
Persistence of stem defects, including bole sinuosity, large branch
size and the occurrence of steep-angled branches (i.
e., forks and ramicorns), and the efficiency of early
selection against these traits, were investigated in 90 open-pollinated
families of Douglas fir (Pseudotsuga menziesii var. menziesii) from
coastal Oregon, USA. Trees originally measured for these traits at age 12 were remeasured at age 24 in three progeny test plantations. The
majority of trees scored as having ramicorn branches
at age 12 (62%) still had them at age 24, but most forks (53%) had become ramicorns by the second measurement. Thus, there seems
little need to score forks and ramicorns separately;
simply counting the number of whorls with steep-angled branches seems
sufficient for selection purposes. Branch size scores were relatively
consistent between the two ages, but not scores for bole sinuosity. Because of
low estimated individual and family heritability estimates (<less or
=>0.13 and <less or =>0.41, respectively), predicted genetic responses
in diameter at breast height (DBH) and individual stem-defect traits were only
modest for this population. Nevertheless, with the exception of sinuosity,
genetic correlations between comparable stem-defect traits at the two ages were
strong (rA<more or => 0.82), and predicted
responses in traits at age 24, from selection at age 12, were nearly as great
as responses expected if selection was delayed until age 24. Branch size and
occurrence of steep-angled branches were unfavourably
(positively) correlated with DBH (estimated rA= 0.56
and 0.41, respectively). Thus, it is important to include these stem defect
traits as selection criteria in Douglas fir breeding programmes,
if stem volume growth is to be improved without sacrificing wood quality.
OSU Link
58. Vargas-Hernandez, J. and W.T. Adams. 1991. Genetic variation of
wood density components in young coastal Douglas-fir: implications for tree
breeding. Canadian-Journal-of-Forest-Research 21(12): 1801-1807.
Keywords: genetic
tree improvement
genetic relationships
wood quality
growth
Abstract:
A study was made of the genetic control of wood density components (earlywood density, latewood density, and latewood
percentage) and their relationships with overall density in coastal Douglas fir
(Pseudotsuga menziesii var.
menziesii) to assess the usefulness of this
information in breeding for wood density. The genetic relationships of wood
density with intra-ring density variation and bole volume growth were also
investigated. Increment cores were taken at breast height from 15-yr-old trees
of 60 open-pollinated families growing in the Coyote Creek progeny test plantation
near Eugene,
Oregon,
during summer 1988. Averages across each core for overall wood density, its
components and intra-ring density variation were determined by using X-ray
densitometry. Bole volume at age 15 yr for the same trees was derived from tree
height and diameter at breast height measurements taken at the end of the 1987
growing season. Although wood density components varied significantly among
families and were under moderate genetic control (individual-tree heritability
(hisuperscript 2) >0.24), none had a higher
heritability than overall density (hisuperscript 2 =
0.59). Density components had strong genetic correlations with overall density
(r <more or => 0.74), but were also strongly related among themselves
(0.57 <less or => r <less or =>0.92). Thus, density components have
limited value in improving the efficiency of selection for overall density.
Overall density was positively correlated with intra-ring density variation (r
= 0.72) and negatively correlated with bole volume (r = -0.52). However,
comparison of several selection indices incorporating wood density and one or
more growth traits showed that it is possible to obtain substantial gains in
bole volume without loss in (or even with a modest increase in) wood density.
By restricting the response in wood density, the change in intra-ring density
variation can also be limited.
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59. Vargas-Hernandez, J. and W.T. Adams. 1992. Age-age correlations
and early selection for wood density in young coastal Douglas-fir.
Forest-Science 38(2): 467-478.
Keywords: genetic
tree improvement
genetic relationships
wood quality
Abstract:
Age-age correlations and age-associated changes in the genetic control
of wood density and its components (earlywood
density, latewood density, and latewood proportion) were investigated in
15-yr-old trees of 60 open-pollinated families of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) in Oregon.
The possibility of using wood density components as secondary traits to
increase the efficiency of early selection for overall wood density was also
explored. Heritability estimates for overall density and its components
increased with age, mainly because of a decrease in the error variance as the
number of rings in the core sample increased. Overall density and its
components at age 15 yr had strong genetic correlations with their respective
traits at all younger ages analysed. Moreover, with
few exceptions, age-age genetic correlations were greater than phenotypic
correlations. Early selection to improve overall density at age 15 yr was quite
efficient (relative efficiency >79%), even when selection was based on core
density at the youngest age (7 yr). Using wood density components as secondary
traits produced a slight increase in the efficiency of early selection only at
the youngest ages, presumably because age-age correlations for overall core
density were already strong, limiting the potential for additional improvement.
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60. Vargas-Hernandez, J. and W.T. Adams. 1994. Genetic relationships
between wood density components and cambial growth rhythm in young coastal
Douglas-fir. Canadian-Journal-of-Forest-Research 24(9): 1871-1876.
Keywords: genetic
tree improvement
genetic relationships
wood quality
tree phenology
growth
Abstract:
Genetic relationships of wood density, and its components, with
cambial growth rhythm traits were examined in a 15-year-old progeny test of
coastal Douglas fir (Pseudotsuga menziesii
var. menziesii) in Oregon,
in an attempt to better understand the genetic control of wood formation, and
to assess the potential effect of selecting for increased wood density on
adaptation of trees. Timing of diameter growth during the 1987 growing season
was determined in an earlier study, and wood formation traits were estimated by
X-ray densitometry of increment core samples. Wood formation traits were under
weak genetic control (hisuperscript 2<0.20).
Duration of earlywood and latewood formation were mostly determined by the timing of latewood transition.
Overall core density was negatively correlated with the dates of cambial growth
initiation (rA=-0.41) and latewood transition (rA=-0.62), and positively correlated with the date of
cambial growth cessation (rA=0.40). As a result of
these relationships, higher wood density was associated with a longer duration
of cambial growth (rA=0.67) and a slower rate of wood
formation (rA=-0.37). All density components showed
similar relationships with cambial phenology and wood
formation traits. Selection for increased wood density is expected to cause only
a slight extension of the cambial growth period, but it would also cause an
earlier transition to latewood formation, negatively affecting growth rate.
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61. Vargas-Hernandez, J., W.T. Adams and R.L. Krahmer.
1994. Family variation in age trends of wood density traits in young coastal
Douglas-fir. Wood-and-Fiber-Science 26(2): 229-236.
Keywords: genetic
tree improvement
genetic relationships
wood quality
Abstract:
Changes in ring density and its components with increasing distance from
the pith (i.e. age trends) were examined in 15-yr-old trees from 60
open-pollinated families of coastal Douglas fir [Pseudotsuga
menziesii] grown in the Coyote Creek progeny test
plantation near Eugene, Oregon. Earlywood, latewood,
and overall densities of each annual ring, obtained by X-ray densitometry of
increment cores, were weighted by the area of the ring occupied by each trait,
relative to the total stem cross-sectional area at breast height for the trait.
Age trends in weighted values differed among traits but, with the exception of earlywood density, family variation was not detected.
Weighted earlywood density (WED) steadily increased
from pith to bark in some trees, while in other trees a plateau occurred at age
11 or later. Significant family differences were found in the proportion of
trees reaching a plateau in WED by age 12. This proportion was under moderate
genetic control (family hsuperscript 2=0.30) and was
not genetically correlated with overall core density or stem growth at age 15. Although
there are reasons to hypothesize that the plateau in WED is an indication of
transition from juvenile to mature wood formation, this hypothesis needs to be
verified in older trees.
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62. Vargas-Hernandez, J.J., W.T. Adams and D.G. Joyce. 2003.
Quantitative genetic structure of stem form and branching traits in Douglas-fir
seedlings and implications for early selection. Silvae-Genetica
52(1): 36-44.
Keywords: genetic
tree improvement
nursery operations
growth
genetic relationships
wood quality
Abstract:
Open-pollinated (OP) and full-sib (FS) families of coastal Douglas fir (Pseudotsuga menziesii var. menziesii) were grown in two replicated nursery regimes to
evaluate the magnitude and repeatability of genetic parameter estimates for
stem form (stem sinuosity, forking) and branching (number, length and angle of
branches) traits in 2-year-old seedlings, and the relationships of these traits
with stem growth. With data from older trees of the OP families growing in the
field (ages 12 and 24), genetic control of similar traits was compared at the
different ages, and nursery-field correlations (rxy)
were estimated. With the exception of forking, estimates of family heritability
(h2f) were moderate to strong for stem form and branching traits in seedlings
(0.32<less or =>h2f<less or =>0.94; mean=0.73), and similar to
growth traits (0.45<less or =>h2f<less or =>0.90; mean=0.75).
Family performance and estimates of genetic parameters were relatively stable
across nursery regimes and family type. Genetic relationships among traits in
seedlings were similar to those observed in older field-grown trees, indicating
that these traits are controlled by similar sets of genes in the two age
classes. Nursery-field correlations between comparable traits were consistent
across nursery regimes, but rxy was strong enough to
be useful for early testing purposes (i.e. | rxy |
<more or =>0.30), only for number of whorls with steep-angled branches
(WSAB), branch length, and branch angle in older trees. Predicted gains from
early selection for these or correlated traits were at least 40-50% of those expected
from selection at older ages. Because of unfavourable
genetic correlations, selection for stem growth potential alone at the seedling
stage is expected to produce unfavourable impacts on
WSAB and stem sinuosity in older trees. To avoid such negative effects on wood
quality, both stem form and branching traits should be included as selection
criteria in Douglas fir breeding programmes.
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63. Woods, J.H., D. Kolotelo and A.D. Yanchuk. 1995. Early selection of coastal Douglas-fir in a
farm-field test environment. Silvae-Genetica 44(4):
178-186.
Keywords: genetic
tree improvement
planting operations
site preparation
mechanical preparation
release treatments
chemical release
manual release
genetic relationships
wood quality
growth
Abstract:
Farm-field tests are progeny tests established using intensive site
preparation, close spacing and nearly complete weed control. Early growth and
wood density of coastal Douglas-fir (Pseudotsuga menziesii) in a farm-field environment for up to 7 years
from seed were compared with stem volume and wood density from 11 field sites
at age 13 (20-25 of commercial rotation). The farm-field test material
comprised 70 full-sib families from six 6-tree half-diallels
(some reciprocals and missing crosses) without selfs.
Parent trees were from natural stand selections in the coastal area of British
Columbia, Canada,
and the farm-field test was conducted on southern Vancouver
Island. Family heritabilities
were high for almost all traits in both the farm-field and field sites.
Breeding-value correlations of farm-field heights with field stem volume at age
13 increased from a low of 0.5 for farm-field age 1 and levelled
off at about 0.7 by farm-field age 3. Farm-field diameter with field volume age
13 breeding-value correlations were initially lower than those for height, but
increased to 0.82 by age 7. Wood density breeding value correlations between
field pilodyn assessments at age 13 and farm-field
stem sections at age 6 were 0.83. Maximum family-selection efficiency per year
(including a 5-year breeding delay), relative to direct selection on field
volume 13, reached 162% using index selection on farm-field height and diameter
at age 3. Within-family selection efficiencies per year were highest at age 1
and declined quickly thereafter. All selection in the farm-field test had a
higher efficiency per unit time than selection in field tests. It is concluded
that correctly established farm-field tests will provide greater per year gains
in stem yield and wood density traits than field sites.
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64. Woods, J.H., T. Wang and S.N. Aitken.
2002. Effects of inbreeding on coastal Douglas fir: nursery performance. Silvae-Genetica 51(4): 163-170.
Keywords: genetic
tree improvement
growth
tree/stand health
reproduction
genetic relationships
Abstract:
In advanced generation seed orchards, low levels of inbreeding may be
inevitable as relatedness among individuals in breeding populations increases with each generation. Unlike selfing, low level inbreeding can produce relatively large
number of viable seeds. Following previous study on the effects of inbreeding
on coastal Douglas fir (Pseudotsuga menziesii var. menziesii) filled
seed production, the present study investigated inbreeding on nursery
performance over various cross-types, including outcrosses (inbreeding
coefficient F=0), crosses between half-sibs (F = 0.125), between full-sibs (F =
0.25), between parents and offspring (F = 0.25), and selfing
(F = 0.5). Significant differences were found among cross-types for
germination, seedling mortality, seedling diameter and height, and nursery cull
rate. Inbreeding also increased among-family genetic variability. Cumulative
losses of seedlings at the nursery stage were 18, 33, 31, 36 and 43%,
respectively for the above types of crosses. This result indicates that seeds
with low levels of inbreeding may produce relatively large numbers of seedlings
that meet nursery culling standards and could be used for reforestation,
resulting in negative impacts on the genetic gain realized in field
plantations.
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65. Yanchuk, A.D. 1996. General
and specific combining ability from disconnected partial diallels
of coastal Douglas-fir. Silvae-Genetica 45(1):
37-45.
Keywords: genetic
tree improvement
growth
genetic relationships
Abstract:
GCA and SCA were examined in 36, 6-parent disconnected partial diallels across 4 experimental series in coastal
Douglas-fir (Pseudotsuga menziesii
var. menziesii) in British
Columbia, to examine the
ratios of the 2 genetic variances, the distribution of GCA and SCA effects, and
estimates of genetic gain from GCA and SCA for 3 growth traits. Height at age 7
and height and volume at age 12 were measured on approximately 150 trees per full-sib
family in each diallel, across 11 different test
sites within each series. The average percentage ratio of SCA variance to GCA
variance was 36% across all series and the 3 growth traits, with a range of 19
to 65%. GCA and SCA variances did not appreciably change for height growth from
age 7 to age 12. Diallel set effects were generally
negligible. From theoretical considerations assumed for the diallel
model, clear separations of additive and dominance effects (vis-a-vis
the assumptions of selecting on GCA and SCA variances) are likely not possible:
the effects are subject to degrees of dominance, epistasis
and linkage in the population. However, these genetic details did not manifest
themselves in any noticeable pattern or correlation among GCA and SCA effects.
While these results confirm current strategies in Douglas-fir breeding to
select primarily on GCA, there are opportunities to utilize SCA variance in the
production population. Controlled matings for elite
production populations are now common in coastal Douglas-fir improvement programmes, and controlled crossing with specified parents
could (i) elevate gains by as much as 3.0% in 12-year
volume (assuming competition effects have not biased volume estimates), and
(ii) access additional sets of parents that would otherwise be disregarded.
Gains for height growth from utilizing SCA are lower, which reflect either (i) lower SCA variances associated with height, or (ii)
competition has biased upward volume SCA variance by age 12 (relative to
height).
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66. Yeh, F.C. and J.C. Heaman.
1987. Estimating genetic parameters of height growth in seven-year old coastal
Douglas-fir from disconnected diallels.
Forest-Science 33(4): 946-957.
Keywords: genetic
tree improvement
genetic relationships
growth
Abstract:
A disconnected diallele mating scheme was
carried out on 10 sets each of 6 parents. Seedlings were raised at Cowichan Lake Research Station and planted out after 1 yr
at 11 plantations in British
Columbia where coastal
Douglas fir would be a good choice for reforestation. Data on ht. and survival
were collected after 7 yr and analysed to partition
total phenotypic variation in ht. into portions of additive genetic effect
(GCA), dominance genetic effect (SCA), interaction of plantations with additive
and dominance genetic effects, residual effect and random error. The GCA of the
parents within the sets was highly significant and its variance was the most
important source of genetic variation. The GCA by plantation interaction was
large and its variance was approx. 42% of the GCA variance. Effects due to SCA
of parent trees and SCA by plantation interaction were also significant, but
their variances were small in comparison with the GCA variance. The
heritability estimate for 7-yr ht. was 0.13. Results are discussed in relation
to gains to be expected from the improvement of this species.
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