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.
OSU Link
Non-OSU
Link
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.
OSU
Link
Non-OSU Link
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.
OSU Link
Non-OSU Link
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.
OSU
Link
Non-OSU
Link
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.
OSU
Link
Non-OSU
Link
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).
OSU
Link
Non-OSU
Link
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.
OSU
Link
Non-OSU
Link
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.
Non-OSU Link
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.
OSU
Link
Non-OSU Link
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.
OSU
Link
Non-OSU
Link
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.
OSU
Link
Non-OSU Link
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.
OSU
Link
Non-OSU Link
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.
OSU
Link
Non-OSU
Link
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
Link
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
Link
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.
OSU Link
Non-OSU
Link
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.
OSU Link
Non-OSU Link
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
Link
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
Link
Non-OSU
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
Non-OSU Link
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
Link
Non-OSU Link
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
Link
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
Link
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
Non-OSU Link
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
Non-OSU
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
Link
Non-OSU
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</