1. 2000. Annual Report 1999/2000 -
Keywords: genetic tree improvement
tree/stand protection
tree physiology
reproduction
Abstract:
Includes highlights of 1998-1999; a note to the cooperative members from Tom
Adams; Introduction; Current research on seedling drought physiology of Douglas
fir [Pseudotsuga menziesii],
field drought study - genetics of drought sensitivity in older trees, early testing
revisited, miniaturized orchard study, pollen contamination study; activities
planned for 2000-2001; list of staff publications and abstracts; and a summary
of financial support for the fiscal year 1999-2000.
2. 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',
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
Non-OSU Link
3. Colangeli, A.M., L. McAuley and J.N.
Owens. 1990. Seasonal occurrence of potential ice-nucleating bacteria on
Douglas fir foliage and seed cones. New-Forests 4(1): 55-61.
Keywords: seed orchard management
tree/stand protection
tree/stand health
reproduction
Abstract: Plant
frost damage can involve interactions between certain surface bacteria and low
temperatures. The bacteria contain glycoproteins,
which can nucleate ice above -5 degrees C, thus making the plants on which they
live more susceptible to freezing. Preliminary studies to determine if bacteria
were present on Douglas fir (Pseudotsuga menziesii), and whether they exhibited ice-nucleating
properties, are reported. Total bacteria and fluorescent Pseudomonas
populations were monitored on buds, conelets and
foliage of five trees in a Douglas fir seed orchard on
4. Colangeli,
A.M., J.N. Owens and S.J. Morris. 1989. Factors affecting cone and seed
production in Douglas fir. BC Ministry of Forests FRDA-Report
057. 19 p.
Keywords: seed orchard management
tree/stand protection
reproduction
Abstract: Reduced
seed yield in 1986 on 4 Pseudotsuga menziesii trees in a
5. 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
6. Copes, D.L. 1992. Effects of
long-term pruning, meristem origin, and branch order
on the rooting of Douglas-fir stem cuttings.
Canadian-Journal-of-Forest-Research 22(12): 1888-1894.
Keywords: seed orchard management
reproduction
Abstract: The
rooting percentages of cuttings taken from 14 Douglas-fir (Pseudotsuga
menziesii) clones were examined annually from 1974 to
1988. The trees were 10 and 13 yr old in 1974 and were pruned to 2.0 m in 1978
and 1979 and then recut annually to 0.5, 1.0, or 1.5
m, starting in 1983. The pruned trees showed no evidence of reduced rooting
percentage even after 15 yr; average rooting increased from 47% in 1974 to 74%
in 1986. Rooting percentage was significantly influenced by tree height.
Cuttings collected from 0.5 m tall ramets exhibited
better rooting than cuttings from 1.0 or 2.0 m tall ramets,
and cuttings from 1.0 m tall ramets rooted better
than cuttings from 2.0 m tall ramets. Rooting of
cuttings collected from 0.5 m high subinterval zones within trees showed a
negative linear relation between rooting percentage and collection height.
Cuttings collected from the 0-0.5 m zone rooted 25% better than cuttings from
the 1.5-2.0 m zone of the 2-m tall trees. A test of rooting of larger, more
orthotropic cuttings gathered from the upper flat surface of pruned ramets indicated that the cuttings from the top rooted
significantly less than the smaller, more plagiotropic
cuttings from the contiguous side areas (24 vs. 33%, respectively). Meristems of secondary origin showed significantly greater
rooting than meristems of primary origin. Comparison
of rooting of second-order and first-order meristems
of secondary origin indicated that second-order twigs averaged 26% better
rooting than the first-order branch tips when the cuttings were collected in
January and placed in the rooting beds in February.
7. Copes, D.L. and M. Bordelon. 1994. Effects of tree spacing and height
reduction on cone production in two Douglas-fir seed orchards.
Western-Journal-of-Applied-Forestry 9(1): 5-7.
Keywords: seed orchard management
planting operations
reproduction
Abstract: Two
treatments involving tree spacings (12 and 24 ft)
within rows spaced 24 ft apart and height control (topped or not topped at 20
ft) were evaluated in 17- and 22-yr-old coast Douglas fir (Pseudotsuga
menziesii var. menziesii)
seed orchards in
8. Crook, R.W. and W.E. Friedman.
1992. Effects of pollen tube number and archegonium number
on reproduction in Douglas-fir: significance for seed orchard management.
Canadian-Journal-of-Forest-Research 22(10): 1483-1488.
Keywords: genetic tree improvement
seed orchard management
reproduction
tree/stand health
Abstract: Analyses
of the relations between pollen tube number or archegonium
number and the number of fertilization events per ovule (fertilization number)
in Douglas fir (Pseudotsuga menziesii)
growing at a seed orchard near Centralia, Washington, indicated strong trends
toward higher levels of simple polyembryony as both
pollen tube number and archegonial number increased
on a per seed basis. These relations have a significant bearing on the
management of conifer seed orchards. Simple polyembryony
has been proposed to be an effective means of increasing competition on a per
seed basis in conifers and, potentially, the overall fitness of progeny. In
conifers, supplemental mass pollination has the direct effect of increasing the
number of pollen tubes per ovule. Clonal variation in
average number of archegonia per ovule is also likely to exist among conifers.
It is proposed that when used together, supplemental mass pollination and
selection of clones with high archegonial averages
may enhance the fitness of seed orchard progeny.
9. Edwards, D.G.W. and Y.A. El-Kassaby. 1988. Effect of flowering phenology,
date of cone collection, cone-storage treatment and seed pretreatment on yield
and germination of seeds from a Douglas-fir seed orchard.
Forest-Ecology-and-Management 25(1): 17-29.
Keywords: seed orchard management
reproduction
tree phenology
Abstract: The
effects were studied of reproductive phenology, date
of cone harvest, cone storage and seed pretreatment on yield and germination of
seeds from a Douglas fir seed orchard in
10. 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
11. 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),
12. 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.
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
13. El Kassaby,
Y.A., S. Barnes, C. Cook and D.A. MacLeod. 1993. Supplemental mass pollination success rate in a
mature Douglas-fir seed orchard. Canadian-Journal-of-Forest-Research 23(6):
1096-1099.
Keywords: genetic tree improvement
seed orchard management
reproduction
Abstract: Supplemental
mass pollination (SMP) success rate in a mature Douglas fir (Pseudotsuga menziesii) seed
orchard in
14. El Kassaby,
Y.A., K. Chaisurisri, D.G.W. Edwards and D.W. Taylor. 1993. Genetic control of germination parameters of
Douglas-fir,
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),
15. 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
16. El Kassaby,
Y.A., D.G.W. Edwards and C. Cook. 1990a. Impact of crop management practices on seed yield
in a Douglas-fir seed orchard. Silvae-Genetica
39(5-6): 226-230.
Keywords: seed orchard management
tree/stand protection
reproduction
tree/stand health
Abstract: The impact
of two crop-management practices, supplemental mass pollination (SMP) and
overhead cooling, on seed yield in a 13-yr-old Douglas fir (Pseudotsuga
menziesii) seed orchard was studied in Saanichton, British Columbia. A 2x2 factorial trial of
SMP/no SMP and cooling/no cooling was applied. There were no significant
differences in potential seed yield per cone, average number of successful
fertilizations, and average number of filled seeds per cone between cooling or
SMP treatments or combinations. Results indicated that within-orchard pollen
cloud was not a factor limiting seed yield. Average number of seeds infested by
the Douglas fir seed wasp (Megastigmus spermotrophus) larvae was significantly (P<0.05) less
when cooling was applied, indicating that the treatment was effective in
disrupting the synchrony between the presence of ovipositing
females and developing cones.
17. El Kassaby,
Y.A., D.G.W. Edwards and D.W. Taylor. 1990b. Effect of water-spray cooling
treatment in a Douglas-fir seed orchard on seed germination. New-Forests
4(2): 137-146.
Keywords: seed orchard management
reproduction
tree phenology
Abstract: As part
of an assessment of seed orchard crop management practices, results are given
of an experiment undertaken to test the effect of cooling treatment on
germination in a 13-year-old full-sib Douglas fir (Pseudotsuga
menziesii) seedling seed orchard at
18. El Kassaby,
Y.A., A.M.K. Fashler and O. Sziklai. 1984. Reproductive phenology and
its impact on genetically improved seed production in a Douglas-fir seed
orchard. Silvae-Genetica 33(4/5): 120-125.
Keywords: seed orchard management
tree phenology
reproduction
Abstract: Reproductive
phenology of buds was monitored for 2 yr in a Douglas
fir seed orchard to determine the validity of the theory of panmictic
equilibrium. There was a significant variation within clones and families in
dates of seed-cone and pollen-cone bud burst, suggesting a major deviation from
panmictic equilibrium. This would reduce the size of
the breeding population and reduce seed yield. This effect could be reduced,
and seed production maximized, either by the use of an irrigation mist system
to delay bud development, or by the intensive application of booster
pollination.
19. 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.
20. 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
21. El Kassaby,
Y.A. and A.J. Thomson.
1996. Parental rank changes associated with seed biology and nursery practices
in Douglas-fir.
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
22. 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
23. Fernando, D.D., J.N. Owens and P.v. Aderkas. 1998. In vitro
fertilization from co-cultured pollen tubes and female gametophytes of Douglas
fir (Pseudotsuga menziesii).
Theoretical-and-Applied-Genetics 96(8): 1057-1063.
Keywords: genetic tree improvement
reproduction
Abstract: A
previous attempt on in vitro fertilization (IVF) in conifers resulted in pollen
tube penetration of female gametophytes, but because of the rapid decline in
egg viability, no further interaction occurred. It is reported that, for the
first time, IVF has been achieved in conifers. Using Douglas fir (Pseudotsuga menziesii), a two-step
process is described which involved induction of pollen tubes in culture
followed by introduction of isolated female gametophytes at the tips of growing
pollen tubes. Pollen tubes penetrated the introduced isolated female
gametophytes at various places, but a number of tubes entered the egg cell
through the neck cells similar to the in vivo condition. Under current culture
conditions, longevity of pollen tubes and eggs was improved resulting in the
release of sperms, fusion of gametes, and initial formation of the proembryo. Continued plasmolysis
of the egg limited the number of successful gametic
interactions. IVF has been accomplished in flowering plants in several ways,
but the gametophyte-gametophyte IVF system described in here is unique. IVF
offers a novel breeding technology that takes advantage of the sexual
reproductive route. When coupled with hybridization and genetic transformation,
IVF could result in the development of stable novel genotypes of economically
superior trees.
24. Fernando, D.D., J.N. Owens, P.v. Aderkas and T. Takaso. 1997. In vitro pollen tube growth and penetration
of female gametophyte in Douglas fir (Pseudotsuga menziesii). Sexual-Plant-Reproduction 10(4): 209-216.
Keywords: genetic tree improvement
reproduction
Abstract: Pollen
tube and female gametophyte interactions in Douglas fir (Pseudotsuga
menziesii) were examined in vitro. Formation of
pollen tubes in Douglas fir occurred on a modified MS medium in which
concentrations of H3BO3 and Ca(NO3)2 were altered and supplemented with sucrose
and polyethylene glycol. Addition of 100 micro g/ml H3BO3 and 300 micro g/ml Ca(NO3)2 resulted in optimum pollen viability. Lack of H3BO3
inhibited pollen tube formation. Addition of H3BO3 and Ca(NO3)2
significantly increased pollen tube formation within one week in culture. Using
a medium supplemented with mannitol, viability of
Douglas fir pollen can be sustained for 7 weeks in culture, about the same
length of time as in vivo. However, pollen tubes are not formed. This suggests
that the factors responsible for tube formation reside in the external
environment of the pollen. Culture of female gametophytes to examine egg
viability and longevity had not been done previously. Egg viability in culture
is short-lived, and therefore the window to study and manipulate events of
fertilization in Douglas fir is very limited. In spite of this, about 7% of the
female gametophytes that were co-cultured became penetrated by pollen tubes. In
vitro archegonial penetration has been repeatedly achieved,
but pollen tubes also penetrated other parts of the female gametophytes. Pollen
tubes also penetrated non-viable eggs. Most female gametophytes were not
penetrated because of pollen tube branching and swelling, failure of tubes to
orient towards the female gametophytes, or premature pollen tube death due to plasmolysis. This report outlines the first attempt towards
in vitro fertilization in conifers.
25. Johnson, D.R., G.P. Markin, R.C. Reardon and W.K. Randall. 1984. Injecting Metasystox-R at three spacing intervals to improve seed
yield in Douglas-fir. Journal-of-Economic-Entomology 77(5): 1320-1322.
Keywords: tree/stand protection
reproduction
Abstract: Injecting
oxydemeton-methyl into
26. Koerber,
T.W. and G.P. Markin. 1984. Metasystox-RReg.
injections increase seed yield of Douglas-fir in
Keywords: tree/stand protection
tree/stand health
reproduction
Abstract:
Injections of 1.5 g for each 15 cm of tree girth reduced seed damage caused by Contarinia oregonensis and
Barbara colfaxiana, but not that by Megastigmus spermatrophus [M. spermotrophus]. On sites with insect populations high
enough to cause substantial seed losses, treatment increased seed yield per
cone by 38-162%.
27. Krakowski,
J. and Y.A. El-Kassaby. 2003. Effects of
stratification and simulated aging on germination of Douglas-fir seed from a clonal seed orchard. Forest-Genetics 10(1): 65-70.
Keywords: nursery operations
tree/stand health
reproduction
Abstract: Seeds
from 15 Douglas-fir (Pseudotsuga menziesii)
clones were germinated in a factorial design with two pre-treatments (unstratified and stratified) and seven simulated aging
periods (0, 2, 4, 7, 10, 12 and 14 days). Simulated aging consisted of high
temperature (40 degrees C) and relative humidity (100%) exposure, which
simulates physiological stresses and consequent deterioration in long-term
storage. Seed deteriorated as aging treatments lengthened; no germination
occurred after 12 days. Germination parameters (capacity, peak value, speed,
completeness) were calculated, and pre-treatment and aging effects evaluated
using a mixed model analysis of variance. Germination completeness and speed
were higher after two days of aging for stratified seed, whereas only peak
value increased for unstratified seed. After four
days aging, all parameters decreased. Two days of aging enhanced germination
capacity of unstratified seed by 15%, but stratified
seed was still 13% higher. Douglas-fir seed should be stratified before
germination, but unstratified seed can be exposed to
40 degrees C and 100% humidity for two days to augment seedling stock during
the growing season. Ex situ Douglas-fir genetic resource conservation, as well
as more adequate representation of planted genotypes across the landscape, can
benefit from two days of aging, which would ensure slowly-germinating genotypes
are represented in the population.
28. Malavasi,
M.d.-M., S.G. Stafford and D.P. Lavender. 1985. Stratifying, partially redrying and storing Douglas-fir seeds: effects on growth
and physiology during germination. Annales-des-Sciences-Forestieres
42(4): 371-383.
Keywords: nursery operations
reproduction
growth
Abstract: Douglas
fir seeds collected from one coastal and one inland source in Oregon, USA, were
stratified at 3 degrees C for 28 days at 45% m.c.,
and then redried to 35% or 25% m.c.
and/or stored at 3 degrees C for 1 or 3 months. Redrying
stratified seeds to 35% m.c.
did not affect the m.c. of embryos or gametophytes,
but redrying to 25% m.c.
reduced the m.c. of all seed structures. Three months
storage did not alter moisture distribution within seeds. Stratification
reduced the germination % of seeds from the inland source, but hastened
germination speed of seeds from both sources. Redrying
stratified seeds to 35% and 25% m.c.
increased seed vigour and seedling length and dry
weight. Storing stratified seeds without redrying
them generally reduced seed vigour. These results
suggest that it would be advantageous to redry seeds
to a range of 25-35% m.c.
directly before sowing in order to produce vigorous seedlings or allow
expression of stratification benefits.
29. Miller, G.E. 1983b. When is
controlling cone and seed insects in Douglas-fir seed orchards justified?
Forestry-Chronicle 59(6): 304-307.
Keywords: seed orchard management
tree/stand protection
economics
reproduction
Abstract: Two
seed orchards in
30. Miller, G.E. 1986. Damage prediction
for Contarinia oregonensis
Foote (Diptera: Cecidomyiidae)
in Douglas-fir seed orchards. Canadian-Entomologist 118(12): 1297-1306.
Keywords: seed orchard management
tree/stand protection
tree/stand health
reproduction
Abstract: Damage
to Douglas fir (Pseudotsuga menziesii)
in
31. Minore, D. 1986b. Germination, survival and
early growth of conifer seedlings in two habitat types. Pacific-Northwest-Forest-and-Range-Experiment-Station,-USDA-Forest-Service
Research-Paper PNW-RP-348. ii + 25 p.
Keywords: planting operations
reproduction
tree/stand health
growth
Abstract: Seed
germination, and seedling survival and early growth of Douglas fir, western
hemlock, Abies procera and
A. amabilis were studied on clear felled sites in the
A. amabilis/Achlys triphylla
and A. amabilis/Vaccinium membranaceum/Xerophyllum
tenax habitat types in the McKenzie River basin,
Oregon. Severe seed predation and high surface soil temp. in
both habitat types resulted in almost total seedling mortality during the first
season when seeds had been sown on a few large, consolidated seedbeds. Seedling
survival was n.s.d. between habitat types. Survival
of Douglas fir (the only species tested) was better when seeds were sown in
small scattered spots. Habitat type and addition of forest humus did not affect
survival and growth, but shading by stumps and protection from predation using
plastic berry baskets were both beneficial. Soils from both habitats had
similar colour, texture, pH and nutrient content. In
greenhouse studies, seeds of all species began germinating earlier and
continued to germinate for longer in soil from Achlys
sites than in soil from Xerophyllum sites. It is
suggested that unmeasured biological activity may have been responsible for
differences in germination activity between the two soil types.
32. Minore,
D., H.G. Weatherly and P.G. Cunningham. 1993. Sowing at 1.5-cm (0.6-inch) depth
produces heaviest Douglas-fir roots in small containers. Tree-Planters' Notes
44(3): 122-124.
Keywords: nursery operations
tree morphology
growth
reproduction
Abstract: Sowing
seeds of Douglas fir (Pseudotsuga menziesii)
at five depths in Leach Super Cells indicated that the only benefit of deep
sowing in small containers occurred at a depth of 1.5 cm. Sowing at this depth
produced heavier roots without a significant reduction in seedling emergence.
Sowing at greater depths significantly reduced seedling emergence and growth.
33. Mohammed, G.H., K.R. Patel and
W.E. Vidaver. 1989. The control of adventitious root
production in tissue-cultured Douglas-fir. Canadian-Journal-of-Forest-Research
19(10): 1322-1329.
Keywords: nursery operations
reproduction
growth
tree morphology
Abstract: Rooting
percentage and root number in tissue-cultured Douglas fir (Pseudotsuga
menziesii) were examined to assess the influence of
rooting substrate, the concentrations of sucrose and boron in the rooting
medium, shoot height, and shoot generation. Peat/perlite
was a better substrate than agar, producing 70% compared with 0% rooted shoots,
respectively. On peat/perlite, cell divisions were
organized and were associated with tracheid nests,
whereas on agar proliferation was neither organized nor restricted to the
nests. An optimum sucrose concentration of 4% was found for the production of
nodular or rooted shoots. At 4% sucrose and 3 mg/litre
boric acid, 100% of the shoots rooted, and the mean root number was 11. Rooting
percentage and root number were significantly greater with shoots that were 3
cm tall rather than 2 or 1 cm tall. Shoot responses were more rapid in third
and fourth generation shoots, with at least 80% rooted or nodular after 4
weeks, compared with only 36% from the second generation.
34. Muller, C., E. Falleri, E. Laroppe and M. Bonnet
Masimbert. 1999. Drying and storage of prechilled Douglas fir, Pseudotsuga
menziesii, seeds. Canadian Journal of
Keywords: nursery operations
reproduction
Abstract: Douglas
fir, Pseudotsuga menziesii,
seeds exhibit relative dormancy as they do not germinate at suboptimum
temperature (15°C), whereas at optimum temperature (20°C) some germination
occurred. Thus, germination at 15°C was chosen to estimate dormancy release. In
the first experiment, seeds were prechilled at 32%
moisture content (MC) for 0-34 weeks at 3°C. Long chilling treatments enhanced germinability and, more markedly, germination speed both at
20°C and at 15°C. Seeds pretreated for the longest periods were then dried to
6.7% MC and stored up to 6 months without any detrimental effect on germination
at 15°C. In the second experiment, seeds from a second seedlot
were prechilled for 18 weeks and then stored at three
different MCs (6.7, 7.2 and 8.1%) over a period of 17 months. Seeds stored at
the lowest MC germinated fastest and to the highest percentage both at 15 and
20°C. In the nursery, seedling emergence tests confirmed results from this
experiment.
35. Poulsen, K.M. 1996. Prolonged cold, moist
pretreatment of conifer seeds at controlled moisture content. Seed Science
and Technology 24:75-87.
Keywords: nursery operations
reproduction
tree/stand health
Abstract: Cold
pretreatment of imbibed seed (stratification) and seed kept at controlled
moisture contents for 3-14 weeks was tested for commercial seedlots
of Abies nordmanniana, Abies procera, Pseudotsuga menziesii and Picea sitchensis in order to give
recommendations for nursery practice. The temperature tolerance of treated seed
was tested by germinating seed at four temperature regimes. It was possible to pretreat Abies nordmanniana seed at controlled moisture content, but the
performance was not improved compared to the traditional six weeks
stratification of imbibed seed. For Abies procera seed pretreatment at controlled moisture content
for 2 + 8 weeks (2 weeks imbibed followed by 8 weeks at controlled moisture
content) or more, significantly improved the performance at the germination
temperatures 15 and 30°C. For Pseudotsuga menziesii seed pretreatment at controlled moisture content
for up to 2 + 12 weeks was superior, especially at low germination
temperatures, and it was possible to redry pretreated
seed to 8% moisture content without loss of the pretreatment effect or
germination capacity. For Picea sitchensis
seeds the controlled moisture content method for a duration
of 7-10 weeks proved efficient and pretreated seed of this species also
tolerated redrying. It is recommended that these
improved pretreatment methods should be introduced into the nurseries.
36.
Keywords: seed orchard management
reproduction
economics
Abstract: In a
seed orchard in
37.