Genetic structure and patterns of genetic variation among populations in eastern white spruce (Picea glauca)

1997 ◽  
Vol 27 (2) ◽  
pp. 189-198 ◽  
Author(s):  
P Li ◽  
J Beaulieu ◽  
J Bousquet
2004 ◽  
Vol 53 (1-6) ◽  
pp. 141-148 ◽  
Author(s):  
M. R. Lesser ◽  
W. H. Parker

Abstract Ecologically based management of white spruce (Picea glauca [Moench] Voss.) requires an understanding of its patterns of adaptive variation. This understanding will become increasingly important under changing climate conditions. Five common garden tests and a greenhouse trial established in 2002 across Ontario were used to assess levels of genetic variation and relate this variation to local climate. Growth and phenological variables, including height, root collar diameter, survival, timing of spring budflush, and timing of fall budset were measured. Intraclass correlation coefficients were calculated for all traits to determine levels of genetic variation. Simple linear regressions were used to relate these differences to local climate conditions. After two growing season’s levels of between-provenance genetic variation ranged from 0 percent for several of the budflush variables to 22 percent for 2003 survival at the Englehart field trial. Overall, growth variables showed higher levels of between-provenance variation than phenological variables. Variation was predominately explained by longitude, a surrogate for precipitation patterns in Ontario, and temperature variables related to the growing season with r2 values ranging from 0.03 to 0.55. Generally, patterns of adaptive variation followed a southeast to northwest trend across Ontario. Northern sources flushed earlier and set bud earlier, while southern sources demonstrated superior growth. Results support previous white spruce genecology studies showing superior growth of sources from the Ottawa valley region of Ontario and Quebec.


2000 ◽  
Vol 78 (6) ◽  
pp. 768-780 ◽  
Author(s):  
Om P Rajora ◽  
Bruce P Dancik

Genetic variation, structure, and evolution of 12 populations of putative Engelmann spruce (Picea engelmanii Parry), white spruce (Picea glauca (Moench) Voss), and Engelmann - white spruce natural hybrids from the sympatric areas and two populations of white spruce from the allopatric areas in Alberta were examined using 23 allozyme loci coding for 13 enzymes in needles. Although most of the alleles were widespread, unique alleles were found in 9 of the 14 populations. No species-specific allele was observed. However, allele frequency differences were observed between the putative Engelmann and white spruce populations at a number of loci. Frequencies of 13 alleles showed significant correlation with altitude, those of 11 alleles showed correlation with latitude, and those of 3 alleles showed correlation with longitude. On average, 66.2% (99% criterion) of the loci were polymorphic, the number of alleles per locus was 1.88, the number of alleles per polymorphic locus was 2.88, and the observed and expected heterozygosities were 0.063 and 0.184, respectively. Genetic variability of allopatric white spruce, putative Engelmann, sympatric white spruce, and hybrid populations was quite comparable. The mean FST estimate was 0.123 for the total populations. Canonical discriminant functions separated four putative Engelmann spruce populations from the fifth putative Engelmann spruce population and from the allopatric and sympatric white spruce and sympatric putative hybrid populations. A cluster analysis from genetic distances generally separated allopatric and sympatric white spruce populations from the putative Engelmann spruce and hybrid populations. A Wagner tree of the 14 populations produced two main branches; one branch consisting of two allopatric and two sympatric white spruce and one putative hybrid populations, and another branch consisting of the remaining nine spruce populations representing putative Engelmann spruce, putative hybrids, and sympatric white spruce. Putative hybrids showed lower distances to white spruce from the canonical discriminant analysis, whereas they showed lower distances to putative Engelmann spruce from the genetic distance analysis. High allozyme genetic identities between putative Engelmann and white spruce and allelic differentiation related to altitude in Alberta suggest that Engelmann spruce could at best be considered as a subspecies of Picea glauca, with white spruce named as Picea glauca ssp. glauca and Engelmann spruce named as Picea glauca ssp. engelmannii.Key words: Picea glauca, Picea engelmannii, biosystematics, natural hybridization, species differentiation, genetic divergence.


1986 ◽  
Vol 28 (1) ◽  
pp. 149-153 ◽  
Author(s):  
Steven Craig Stewart ◽  
Daniel J. Schoen

Segregation patterns of six enzyme loci expressed in megagametophytes of white spruce (Picea glauca) were studied as part of an investigation of the mating pattern in a clonal seed orchard. More than 3000 megagametophytes from 79 trees representing 18 clones were assayed. The single locus patterns of segregation for each enzyme locus are consistent with simple Mendelian inheritance. The two locus patterns of segregation reveal that Idh and Gdh are tightly linked with an estimated recombination rate of 0.027 ± 0.004. No other pair of loci deviates significantly from the ratios expected for unlinked loci. Little heterogeneity in the pattern of gametic segregation was detected among ramets within clones or among clones for any of the loci. The results contribute to knowledge of genetic variation in this species and provide a basis for assumptions about segregation made in mating system estimation models.Key words: segregation, linkage, allozymes, Picea glauca, white spruce.


2004 ◽  
Vol 34 (6) ◽  
pp. 1311-1318 ◽  
Author(s):  
S Y Zhang ◽  
Qibin Yu ◽  
Jean Beaulieu

This study investigated the genetic variation in veneer quality of white spruce (Picea glauca (Moench) Voss) and its correlation with tree growth and wood density. A total of 270 sample trees from 35 families were harvested from 36-year-old provenance-progeny trials at two sites through a thinning operation. A 36-cm long bolt was collected from each sample tree at an 8-foot (or 2.45 m) height for this veneer quality study. The results indicate that conversion of fast-grown white spruce into veneer and plywood may present some problems. Low wood density, numerous knots, and possibly a high proportion of juvenile wood appear to be major factors contributing to low veneer stress grading, resulting in a production of low-quality veneer. This study also showed that the environmental factors at the two sites played an important role in determining veneer quality and tree radial growth. The narrow-sense heritability for veneer density, veneer modulus of elasticity, and veneer roughness were 0.62, 0.13, and 0.14, respectively. The results revealed considerable phenotypic variation and relatively high additive genetic variation in the veneer modulus of elasticity. The phenotypic and genetic correlations between ring width and veneer density or veneer modulus of elasticity were negative. A positive phenotypic and genetic correlation was found between veneer density and veneer modulus of elasticity. This suggests that selection for tree volume growth in white spruce would lead to a decrease in wood density and veneer stiffness.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kelly B. Klingler ◽  
Joshua P. Jahner ◽  
Thomas L. Parchman ◽  
Chris Ray ◽  
Mary M. Peacock

Abstract Background Distributional responses by alpine taxa to repeated, glacial-interglacial cycles throughout the last two million years have significantly influenced the spatial genetic structure of populations. These effects have been exacerbated for the American pika (Ochotona princeps), a small alpine lagomorph constrained by thermal sensitivity and a limited dispersal capacity. As a species of conservation concern, long-term lack of gene flow has important consequences for landscape genetic structure and levels of diversity within populations. Here, we use reduced representation sequencing (ddRADseq) to provide a genome-wide perspective on patterns of genetic variation across pika populations representing distinct subspecies. To investigate how landscape and environmental features shape genetic variation, we collected genetic samples from distinct geographic regions as well as across finer spatial scales in two geographically proximate mountain ranges of eastern Nevada. Results Our genome-wide analyses corroborate range-wide, mitochondrial subspecific designations and reveal pronounced fine-scale population structure between the Ruby Mountains and East Humboldt Range of eastern Nevada. Populations in Nevada were characterized by low genetic diversity (π = 0.0006–0.0009; θW = 0.0005–0.0007) relative to populations in California (π = 0.0014–0.0019; θW = 0.0011–0.0017) and the Rocky Mountains (π = 0.0025–0.0027; θW = 0.0021–0.0024), indicating substantial genetic drift in these isolated populations. Tajima’s D was positive for all sites (D = 0.240–0.811), consistent with recent contraction in population sizes range-wide. Conclusions Substantial influences of geography, elevation and climate variables on genetic differentiation were also detected and may interact with the regional effects of anthropogenic climate change to force the loss of unique genetic lineages through continued population extirpations in the Great Basin and Sierra Nevada.


The Auk ◽  
2000 ◽  
Vol 117 (3) ◽  
pp. 651-662 ◽  
Author(s):  
Corinne Rabouam ◽  
Vincent Bretagnolle ◽  
Yves Bigot ◽  
Georges Periquet

Abstract We used DNA fingerprinting to assess genetic structure of populations in Cory's Shearwater (Calonectris diomedea). We analyzed mates and parent-offspring relationships, as well as the amount and distribution of genetic variation within and among populations, from the level of subcolony to subspecies. We found no evidence of extrapair fertilization, confirming that the genetic breeding system matches the social system that has been observed in the species. Mates were closely related, and the level of genetic relatedness within populations was within the range usually found in inbred populations. In contrast to previous studies based on allozymes and mtDNA polymorphism, DNA fingerprinting using microsatellites revealed consistent levels of genetic differentiation among populations. However, analyzing the two subspecies separately revealed that the pattern of genetic variation among populations did not support the model of isolation by distance. Natal dispersal, as well as historic and/or demographic events, probably contributed to shape the genetic structure of populations in the species.


Nematology ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 165-177 ◽  
Author(s):  
Rasha Haj Nuaima ◽  
Johannes Roeb ◽  
Johannes Hallmann ◽  
Matthias Daub ◽  
Holger Heuer

Summary Characterising the non-neutral genetic variation within and among populations of plant-parasitic nematodes is essential to determine factors shaping the population genetic structure. This study describes the genetic variation of the parasitism gene vap1 within and among geographic populations of the beet cyst nematode Heterodera schachtii. Forty populations of H. schachtii were sampled at four spatial scales: 695 km, 49 km, 3.1 km and 0.24 km. DGGE fingerprinting showed significant differences in vap1 patterns among populations. High similarity of vap1 patterns appeared between geographically close populations, and occasionally among distant populations. Analysis of spatially sampled populations within fields revealed an effect of tillage direction on the vap1 similarity for two of four studied fields. Overall, geographic distance and similarity of vap1 patterns of H. schachtii populations were negatively correlated. In conclusion, the population genetic structure was shaped by the interplay between the genetic adaptation and the passive transport of this nematode.


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