Genetic variability among and within closely spaced populations of lodgepole pine

1984 ◽  
Vol 26 (2) ◽  
pp. 177-184 ◽  
Author(s):  
Peggy Knowles

The genetic composition of Pinus contorta var. latifolia as determined by isozyme analysis was assessed and examined at two hierarchical levels; within closely spaced populations and within adjacent subpopulations. Four populations of lodgepole pine consisting of 125 trees each were sampled along an elevational gradient spanning a distance of approximately 2 km in the Front Range of the Rocky Mountains in Colorado. Each population was further divided into five subpopulations. Four isozymes were electrophoretically resolved from needle tissue removed from each tree. Statistics characterizing the genetic structure were calculated including measures of genetic variability, tests of allelic heterogeneity, and F statistics. The results indicate that lodgepole pine has a relatively low level of genetic variation with 44% of its loci polymorphic, an average of 1.33 alleles per locus, heterozygous at 13.5% of their loci, and a polymorphic index of 0.144. Slightly less than 1% of the observed genetic variability resided among the four populations with the remainder residing among the individuals within populations. A slight deficiency of heterozygotes was indicated by the F statistics analysis. Allelic distributions at the subpopulation level indicated that clustering was evident although not a predominant characteristic of the genetic pattern. It is suggested that inbreeding and (or) the pooling of individuals from different breeding groups are likely phenomena contributing to the genetic pattern in lodgepole pine over microgeographical distances.Key words: genetic variability, lodgepole pine, Pinus contorta var. latifolia, isozyme.

1985 ◽  
Vol 63 (4) ◽  
pp. 722-727 ◽  
Author(s):  
Peggy Knowles ◽  
Michael C. Grant

The genetic composition of Pinus contorta var. latifolia as determined by isozyme analysis was examined in terms of its variation over space and time. Four populations of lodgepole pine consisting of approximately 125 trees each were sampled along an elevational gradient spanning a distance of 2 km in the Front Range of the Rocky Mountains in Colorado. Four isozymes were electrophoretically resolved from needle tissue removed from each tree. Ages were estimated from ring counts of either a tree core or a basal cross section of each tree. Gene frequencies were submitted to two-way analyses of variance using a subsampling procedure to generate multiple estimates within each cell. Analyses were performed to examine the variation in gene frequencies for each of the seven alleles resolved, using site (spatial) and age (temporal) as the independent factors. The results indicated that spatial heterogeneity contributes more to variation in genetic composition of lodgepole pine than does temporal heterogeneity. These results support theoretical proposals that spatial environmental heterogeneity under certain conditions can have more effect on variation in genetic composition than does temporal heterogeneity. It is further concluded that under certain conditions the analysis of variance procedure can be a useful analytic tool for examining gene frequency differences.


1979 ◽  
Vol 21 (4) ◽  
pp. 487-503 ◽  
Author(s):  
F. C. Yeh ◽  
C. Layton

A survey was conducted of genetic variation at 25 loci in extracts of individual megagametophytes of lodgepole pine. Collections were made in nine widely separated localities representing four marginal, two intermediate and three central populations. Single populations of lodgepole pine were, on the average, polymorphic at 58.67% of their loci, and had 1.90 alleles per locus. Both expected and observed heterozygosity averaged 0.16. There was a definite trend towards decreased genetic variability at the margins. The measures of gene diversity for the 25 loci showed a 4% but significant effect of interpopulation differentiation; 96% of the total gene diversity resided within populations. Estimated outcrossing rates [Formula: see text] for the nine populations ranged between 0.92–1.29. Comparisons among populations with different levels of outcrossing revealed no clear relationship between [Formula: see text] and amount of genetic variability. The overall pattern of genetic differentiation agrees with expectations based on the neutral mutation theory. However, two loci demonstrated conspicuous clinal variation patterns which may be incompatible with this stochastic model.


1985 ◽  
Vol 63 (2) ◽  
pp. 201-210 ◽  
Author(s):  
John C. Pollack ◽  
Bruce P. Dancik

Five xylem oleoresin monoterpenes and 17 morphological characters of trees in four pine stands in Alberta were measured to delineate pure lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) from jack pine (P. banksiana Lamb.) in a region where hybridization commonly has been reported. Multivariate analysis determined α-pinene, β-phellandrene, and needle length best separated the taxa. The monoterpene composition of two putative hybrid stands at Onoway and Devon closely resembled that of jack pine. Analysis of the four major monoterpenes in an additional 10 stands allowed the identification of a transition zone between jack pine and lodgepole pine stands, which occurred farther west than previously reported and contained stands of highly variable monoterpene types. Trees in this region morphologically resembled lodgepole pine. The presence of variant monoterpene types in Front Range lodgepole pine stands and their absence from the Cypress Hills provide evidence for introgression of jack pine into lodgepole pine. No evidence of gene flow from lodgepole pine to jack pine was found. The two putative hybrid stands at Onoway and Devon probably consisted mostly of jack pine, with a small complement of hybrids.


2004 ◽  
Vol 64 (2) ◽  
pp. 327-336 ◽  
Author(s):  
J. M. M. Santos ◽  
J. F. Maia ◽  
W. P. Tadei

Populations of Anopheles triannulatus from Macapá (AP), Aripuanã (MT), Ji-Paraná (RO), and Manaus-Janauari Lake (AM) were studied using 16 enzymatic loci. The results of the isozyme analysis showed that the population of Macapá presented higher polymorphism (56.3%). The lowest variability was observed in the population of Manaus (p = 25.0; Ho = 0.077 ± 0.046). The results of Wright's F statistics showed unbalance due to excess of homozygotes (Fis > Fst), denoting a certain intrapopulational differentiation. Although the populations are genetically very close (D = 0.003 - 0.052), the dendrogram separates the populations in two groups: Macapá separated from that of Manaus, Ji-Paraná, and Aripuanã. This result may suggest a reduction in the genic flow, which possibly had some influence in the substructuration of the populations.


2011 ◽  
Vol 41 (12) ◽  
pp. 2403-2412 ◽  
Author(s):  
Daniel M. Kashian ◽  
Rebecca M. Jackson ◽  
Heather D. Lyons

Extensive outbreaks of the mountain pine beetle ( Dendroctonus ponderosae Hopkins) will alter the structure of many stands that will likely be attacked again before experiencing a stand-replacing fire. We examined a stand of lodgepole pine ( Pinus contorta var. latifolia Engelm. ex S. Watson) in Grand Teton National Park currently experiencing a moderate-level outbreak and previously attacked by mountain pine beetle in the 1960s. Consistent with published studies, tree diameter was the main predictor of beetle attack on a given tree, large trees were preferentially attacked, and tree vigor, age, and cone production were unimportant variables for beetle attack at epidemic levels. Small trees killed in the stand were killed based mainly on their proximity to large trees and were likely spatially aggregated with large trees as a result of the previous outbreak. We concluded that the driving factors of beetle attack and their spatial patterns are consistent across outbreak severities but that stand structure altered by the previous outbreak had implications for the current outbreaks in the same location. This study should catalyze additional research that examines how beetle-altered stand structure affects future outbreaks — an important priority for predicting their impacts under climate change scenarios that project increases in outbreak frequency and extent.


2005 ◽  
Vol 35 (6) ◽  
pp. 1314-1318 ◽  
Author(s):  
Peter V Blenis ◽  
Wuhan Li

Infection of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) by western gall rust has been shown to decrease with tree height and age, but the effects of those two factors have not been separated. Five replicate artificial inoculations were done on a total of 327 trees of different ages in two height classes. Temperature and percentage of spore germination at the height of inoculation, shoot development (stem elongation at the time of inoculation as a proportion of final shoot elongation), main stem leader length at the time of inoculation, tree height, and tree age were measured. Modeled percentages of infected trees and the number of galls per 10 cm of shoot length decreased by 85% and 88%, respectively, as tree age increased between 2 and 10 years, indicating the undesirability of early, aggressive precommercial thinning of lodgepole pine stands in areas where western gall rust is common. By controlling and (or) statistically accounting for inoculum, microclimate, and phenological factors, it was possible to demonstrate that changes in susceptibility with tree age are sufficient to account for the reduction in infection with tree height.


2009 ◽  
Vol 15 (3) ◽  
pp. 535-548 ◽  
Author(s):  
E. A. H. SMITHWICK ◽  
M. G. RYAN ◽  
D. M. KASHIAN ◽  
W. H. ROMME ◽  
D. B. TINKER ◽  
...  

1986 ◽  
Vol 64 (10) ◽  
pp. 2368-2371 ◽  
Author(s):  
Keith N. Egger ◽  
J. W. Paden

Forty isolates of postfire ascomycetes (Pezizales) were tested for in vitro pathogenicity on seeds and germinants of lodgepole pine, Pinus contorta Dougl. Two known pathogens, Caloscypha fulgens (Pers.) Boud. and Botrytis cinerea Pers., were included as a check of the method. Caloscypha fulgens was the only fungus that caused serious declines in seed germination, although several species of postfire Pezizales were capable of preemergence seed infection. Rhizina undulata Fr. and Pyropyxis rubra (Peck) Egger were strongly pathogenic on germinants. Pyropyxis rubra was not previously known to be pathogenic. Many isolates were weakly pathogenic on germinants under the conditions tested.


2014 ◽  
Vol 64 ◽  
pp. 161-170 ◽  
Author(s):  
Zaki-ul-Zaman Asam ◽  
Mika Nieminen ◽  
Connie O’Driscoll ◽  
Mark O’Connor ◽  
Sakari Sarkkola ◽  
...  

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