Variation in cedar leaf blight (Didymascella thujina) resistance of western redcedar (Thuja plicata)

2007 ◽  
Vol 37 (10) ◽  
pp. 1978-1986 ◽  
Author(s):  
John H. Russell ◽  
Harry H. Kope ◽  
Peter Ades ◽  
Heidi Collinson
Keyword(s):  
British Columbia ◽  
Genetic Correlations ◽  
Natural Populations ◽  
High Elevation ◽  
Leaf Blight ◽  
Population Variation ◽  
Thuja Plicata ◽  
Western Redcedar ◽  
Queen Charlotte Islands ◽  
River Site

Western redcedar ( Thuja plicata Donn ex D. Don) seedlings from a population study with family structure were planted at four sites across coastal British Columbia. All seedlings at the time of planting were infected with cedar leaf blight (CLB) ( Didymascella thujina (E.J. Durand) Maire). CLB severity and tree heights were measured at various ages from 2 to 12 years. There were significant site differences in CLB severity with the coastal hypermaritime site showing the most and with the submaritime site showing the least. Population differences in disease severity were evident with British Columbia coastal, low-elevation populations exhibiting the most resistance and with British Columbia high-elevation and California sources showing the least. Population resistance was consistent across all four sites (all r > 0.90, p < 0.001). Coefficients of additive genetic variation in CLB severity at all four sites varied from 13.2% to 20.1% with narrow-sense heritabilities from 0.21 to 0.66. Type B genetic correlations in CLB severity across sites averaged 0.59. Type A genetic correlations between 6 year CLB severity and height at the Jordan River site on western Vanvouver Island and at the site on the Queen Charlotte Islands were –0.96 and –0.86 (p < 0.001), respectively. Results are discussed with respect to climatic influences and prior exposure to CLB on among- and within-population variation in western redcedar natural populations and impact on gene resource management.

The mating system in natural populations of western redcedar (Thuja plicata)

2001 ◽  
Vol 79 (6) ◽  
pp. 753-756 ◽  
Author(s):  
Lisa M O'Connell ◽  
Frédérique Viard ◽  
John Russell ◽  
Kermit Ritland
Keyword(s):  
British Columbia ◽  
Mating System ◽  
Natural Populations ◽  
Seed Orchard ◽  
Outcrossing Rate ◽  
Thuja Plicata ◽  
Western Redcedar ◽  
Outcrossing Rates ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Thuja Plicata Donn

Outcrossing rates and the correlation of paternity were estimated in six natural populations of western redcedar (Thuja plicata Donn. ex D. Don) in southwestern British Columbia. Over 3000 offspring were assayed, as progeny arrays, for the only sufficiently polymorphic isozyme locus in this species, glucose-6-phosphate dehydrogenase. Estimates of population outcrossing rates ranged from 0.173 to 1.257 and averaged 0.715 ± 0.045 (mean ± SD). Estimates of the correlation of paternity generally did not differ from zero. Six of the seven outcrossing estimates (one population was surveyed in two consecutive years) were higher than a previous seed orchard study. However, these outcrossing rates are still lower than those estimated for most other species of conifers. Population outcrossing rates also showed wide variation, and this variation is discussed in terms of ecological and phenological differences among populations.Key words: Cupressaceae, conifers, isozymes, outcrossing rate, inbreeding.

scholarly journals A quantitative genetic study of starvation resistance at different geographic scales in natural populations of Drosophila melanogaster

2010 ◽  
Vol 92 (4) ◽  
pp. 253-259 ◽  
Author(s):  
JULIETA GOENAGA ◽  
JUAN JOSÉ FANARA ◽  
ESTEBAN HASSON
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Correlations ◽  
Natural Populations ◽  
Food Shortage ◽  
Population Variation ◽  
Phenotypic Variance ◽  
Starvation Resistance ◽  
Natural Genetic Variation ◽  
Quantitative Genetic ◽  
Variation Explained

SummaryFood shortage is a stress factor that commonly affects organisms in nature. Resistance to food shortage or starvation resistance (SR) is a complex quantitative trait with direct implications on fitness. However, surveys of natural genetic variation in SR at different geographic scales are scarce. Here, we have measured variation in SR in sets of lines derived from nine natural populations of Drosophila melanogaster collected in western Argentina. Our study shows that within population variation explained a larger proportion of overall phenotypic variance (80%) than among populations (7·2%). We also noticed that an important fraction of variation was sex-specific. Overall females were more resistant to starvation than males; however, the magnitude of the sexual dimorphism (SD) in SR varied among lines and explained a significant fraction of phenotypic variance in all populations. Estimates of cross-sex genetic correlations suggest that the genetic architecture of SR is only partially shared between sexes in the populations examined, thus, facilitating further evolution of the SD.

The mating system in natural populations of western redcedar (Thuja plicata)

2001 ◽  
Vol 79 (6) ◽  
pp. 753-756 ◽  
Author(s):  
Lisa M. O'Connell ◽  
Frédérique Viard ◽  
John Russell ◽  
Kermit Ritland
Keyword(s):  
Mating System ◽  
Natural Populations ◽  
Thuja Plicata ◽  
Western Redcedar

Genetic architecture and adaptive landscape of interior lodgepole pine (Pinuscontorta ssp. latifolia) in Canada

1995 ◽  
Vol 25 (12) ◽  
pp. 2010-2021 ◽  
Author(s):  
Chang-Yi Xie ◽  
Cheng C. Ying
Keyword(s):  
Genetic Variation ◽  
Central Region ◽  
Population Differentiation ◽  
Genetic Architecture ◽  
Lodgepole Pine ◽  
Natural Populations ◽  
High Elevation ◽  
Population Variation ◽  
Adaptive Landscape ◽  
Growth And Survival

The genetic architecture and adaptive landscape of interior lodgepole pine (Pinuscontorta ssp. latifolia Engelm. ex S. Wats.) in Canada were investigated in a provenance–family plantation located in central British Columbia. Fifty-three natural populations were sampled from three geographic regions covering the entire Canadian range, and their performance in growth and survival was recorded periodically over 20 years. Test results indicate that genetic variation among regions and among populations within regions was highly significant in all the traits investigated and accounted for, respectively, 53% and 41% of the total genetic variation in growth and 41% and 54% in survival. Within-population variation was also significant in growth but not in survival. Interior lodgepole pine in the central region demonstrated less genetic variation than in the northern and southern regions at both the population and family levels. In addition, the proportion of genetic variation associated with population was lower in the central region than in the other regions. Population differentiation in both growth and survival showed discernible elevational and geographic patterns. Regression models describing these adaptive patterns accounted for more than 80% of the among-population variation, and their veracity was verified with independent data. Populations of northern, coastal–interior transition, and high-elevation origin tended to have smaller trees with higher mortality. However, the patterns were not linear but differed in slope and (or) direction among regions. The adaptedness of populations tended to decrease as they were farther away from their origin, with a few exceptions displaying broad adaptation across more than 3° of latitude. As the test proceeded, population differentiation became more evident and adaptive clines became steeper. Some practical implications of these findings have been discussed.

scholarly journals Genetic variation in phenology and growth among and within Norway spruce populations from two altitudinal transects in Mid-Norway

Silva Fennica ◽  
2019 ◽  
Vol 53 (1) ◽  
Author(s):  
Tore Skrøppa ◽  
Arne Steffenrem
Keyword(s):  
High Altitude ◽  
Norway Spruce ◽  
Genetic Correlations ◽  
Natural Populations ◽  
Height Growth ◽  
Population Variation ◽  
Clinal Variation ◽  
Short Term ◽  
Narrow Sense Heritability

Progenies from open pollinated cones collected in natural populations of Norway spruce ( (L. Karst.)) distributed along two altitudinal transects in Mid-Norway were tested in the nursery, in short term tests and in long-term field trials. The populations showed clinal variation related to the mean annual temperatures of the populations, with the earliest bud flush and cessation of shoot elongation and lowest height at age nine years for the high altitude populations. Within population variation was considerable as the narrow sense heritability for these traits was 0.67, 0.31 and 0.09 in one transect and 0.55, 0.18 and 0.14 in the other transect, respectively. Lammas shoots occurred in the short term trials with large variation in frequency between years. There was significant family variation for this trait, but also interactions between populations and year. The variance within populations was considerably larger in the populations from low altitude compared to the high-altitude populations. Significant genetic correlations between height and phenology traits and damage scores indicate that families flushing early and ceasing growth late were taller. Taller families also had higher frequencies of damages. Selection of the top 20% families for height growth in short term tests at age nine years gave a simulated gain of 11% increased height growth at age 18 years in long term trials at altitudes similar to those of origin of the populations. The gain was negative when high altitude populations were selected based on testing in the lowland.Picea abies

Activity levels of Marbled Murrelets in different inland habitats in the Queen Charlotte Islands, British Columbia

1993 ◽  
Vol 71 (5) ◽  
pp. 977-984 ◽  
Author(s):  
Michael S. Rodway ◽  
Heidi M. Regehr ◽  
Jean-Pierre L. Savard
Keyword(s):  
British Columbia ◽  
High Elevation ◽  
Activity Levels ◽  
Old Growth ◽  
Marbled Murrelet ◽  
Queen Charlotte Islands ◽  
Old Growth Forest ◽  
Second Growth ◽  
Old Growth Forests ◽  
Marbled Murrelets

We compared Marbled Murrelet (Brachyramphus marmoratus) activity levels in May, June, and July 1990 in four habitats in the Queen Charlotte Islands, British Columbia: alpine, old-growth forest at high elevation, old-growth forest at low elevation, and second-growth forest. The number of Marbled Murrelet detections was highest in old-growth forests. In alpine areas, small numbers of murrelet detections were mostly of distant birds flying over low-elevation forest. Numbers of detections were higher in low-elevation than in high-elevation old-growth forests in May and July, but not in June. Proportions of detections within smaller radii of survey stations were higher in low elevation forest in all months. The highest activity levels were associated with old-growth forest stands of large Sitka spruce (Picea sitchensis) and western hemlock (Tsuga heterophylla). The few detections that occurred in second-growth forests were mostly of distant birds. Stations in second-growth forest close to stands of old-growth forest had more frequent detections than stations with no old-growth forest nearby. Our results support the association of Marbled Murrelets with old-growth forests. Limitations of the survey methodology are discussed.

scholarly journals Western redcedar population dynamics in old-growth forests: Contrasting ecological paradigms using tree rings

2003 ◽  
Vol 79 (3) ◽  
pp. 517-530 ◽  
Author(s):  
Lori D Daniels
Keyword(s):  
British Columbia ◽  
Population Dynamics ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
Silver Fir ◽  
Old Growth ◽  
Western Redcedar ◽  
Old Growth Forests ◽  
Gap Phase ◽  
Coastal British Columbia

In coastal British Columbia, late-successional forests dominated by western redcedar (Thuja plicata Donn ex D. Don) are structurally complex, with deep multi-layered canopies, large trees that are > 250 years old, and abundant coarse woody debris (CWD). These forests are presumed to be "old-growth" forests in which fine-scale gaps are the dominant disturbance regime, accounting for their structural diversity. In this study, I have used tree-ring analyses to investigate western redcedar regeneration dynamics in these old-growth forests. Western redcedar dominates canopies of many stands, but is rare in the understorey although it tolerates shade. The traditional interpretation is that western redcedar depends on catastrophic disturbance to regenerate and that it is replaced through succession by western hemlock (Tsuga heterophylla (Raf.) Sarg.) and Pacific silver fir (Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes), which are abundant in the understorey. Dominant trees are perceived to represent an even-aged, post-disturbance cohort and the lack of regeneration indicates a population decline in the absence of catastrophic disturbances. In this paper, I investigate four assumptions underlying this interpretation: (1) Tree size indicates age. (2) Populations establish as even-aged, post-disturbance cohorts. (3) Abundant CWD represents recent mortality. (4) Regeneration is insufficient to maintain canopy dominance. Using tree-ring evidence, I show that population dynamics of western redcedar are a combination of gap-phase establishment and a continuous mode of recruitment from the sub-canopy to the canopy. Specifically, size is a poor surrogate for tree age. Age distributions from 15 sites revealed uneven-aged populations, rather than single post-disturbance cohorts. Both logs and snags of western redcedar may persist more than 270 years; they do not represent recent mortality that is disproportionate to the number of live western redcedar in canopy. The regeneration niches of western redcedar and western hemlock overlap. For both species, gap-phase disturbances result in substrate suitable for successful seedling establishment. Preliminary results from dendroecological analysis of radial growth rates of trees in the subcanopy and canopy strata suggest that western hemlock and Pacific silver fir depend on gaps to recruit to the upper canopy, but recruitment of western redcedar may be independent of canopy gaps. I propose that differences in mode of recruitment to the canopy may explain the differences in population structures between western redcedar, western hemlock, and Pacific silver fir in the old-growth forest. These results provide an ecological precedent for use of a range of silvicultural systems, including clearcuts through single-tree harvesting and protection forests, when managing western redcedar in coastal British Columbia. Key words: Coastal British Columbia, disturbance regimes, regeneration dynamics, Thuja plicata, variable retention silviculture

Overturning resistance of western redcedar and western hemlock in mixed-species stands in coastal British Columbia

2007 ◽  
Vol 37 (5) ◽  
pp. 931-939 ◽  
Author(s):  
Kenneth E. Byrne ◽  
Stephen J. Mitchell
Keyword(s):  
British Columbia ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Thuja Plicata ◽  
Specific Information ◽  
Mixed Species ◽  
Stem Form ◽  
Western Redcedar ◽  
Applied Forces ◽  
Coastal British Columbia

Specific information about the applied forces that cause trees to fail is required to validate mechanistic models of windthrow in different forest types. Static tree-pulling tests were conducted to examine the overturning resistance of western redcedar ( Thuja plicata Donn ex D. Don) and western hemlock ( Tsuga heterophylla (Raf.) Sarg.) in a mixed species second-growth stand in coastal British Columbia. Although widely used, tree-pulling techniques are not standardized. Data from three inclinometers were used to estimate stem deflection, which was found to increase with tree slenderness. Differing methods of fitting stem curvature had a small effect on estimates of self-loading at failure. The distance of the pivot point from the centre of the stem base increased with tree diameter. Accounting for the correct self-loading at failure produced a small difference in the overall turning moment regressions but did not improve the fit of these regressions. However, this difference increased with tree size and warrants consideration in future tree-pulling tests with large or plate-rooted trees. The stem mass – overturning resistance relationship had the best fit and was not significantly different for these species in spite of their differences in wood density and stem form.

The phytogeography of Oxalis oregana in British Columbia

1984 ◽  
Vol 62 (7) ◽  
pp. 1561-1563
Author(s):  
R. T. Ogilvie ◽  
R. J. Hebda ◽  
Hans L. Roemer
Keyword(s):  
British Columbia ◽  
Vancouver Island ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
Native People ◽  
Thuja Plicata ◽  
Sea Levels ◽  
Island Populations ◽  
Queen Charlotte Islands ◽  
Polystichum Munitum

The occurrence of Oxalis oregana Nutt. in British Columbia is documented for five localities on the west coast of Vancouver Island and one locality in the Queen Charlotte Islands. The Oxalis populations grow in alluvial Tsuga heterophylla – Picea sitchensis – Thuja plicata – Polystichum munitum forest communities. Rhizomatous reproduction was recorded in all populations and flowering in two of the Vancouver Island populations. Three of the populations may be less than 3000 years old because they would have been inundated by higher sea levels during the middle Holocene. Possible introduction of plants by native people from the Olympic Peninsula, WA, is discussed.

Quantitative genetics of stamen fertility in Spergularia salina (Caryophyllaceae)

1994 ◽  
Vol 72 (11) ◽  
pp. 1598-1604 ◽  
Author(s):  
Linus Svensson ◽  
Helena Persson
Keyword(s):  
Analysis Of Variance ◽  
Quantitative Genetics ◽  
Genetic Correlations ◽  
Natural Populations ◽  
Population Variation ◽  
Hierarchical Design ◽  
Fertility Variation ◽  
Four Levels ◽  
Nested Analysis ◽  
The Relationship

Heritability of stamen fertility was studied in Spergularia salina (Caryophyllaceae), a selfing annual that shows extensive phenotypic variation in stamen fertility. Variation within and among 70 maternal families, derived from plants representing two natural populations from Sweden, was used to estimate heritabilities of stamen fertility for each of the 10 stamen positions in the flower. The hierarchical design of the study allowed partitioning of variation among four levels of organization using nested analysis of variance. Heritabilities ranged from 0.27 to 0.65 for stamen positions in the antipetalous whorl of stamens and from 0.18 to 0.67 for positions in the antisepalous whorl. When stamen fertility was pooled across all stamen positions of a flower, the heritability was 0.73 in both populations. The nested ANOVA indicated that antipetalous stamen positions have comparatively higher proportions of among-family and among-population variation than the antisepalous stamen positions. Furthermore, highly significant genetic correlations exist between the two antisepalous stamen positions STA 2 and STA 8 and among the other eight positions but not so between these two groups. The relationship between tetraploidization and stamen number reductions in Caryophyllaceae is discussed. Key words: Spergularia salina, stamen fertility, stamen position, heritability, hierarchical analysis of variance, quantitative genetics.

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