Mating system in natural populations of eastern white pine in Quebec

1995 ◽  
Vol 25 (10) ◽  
pp. 1697-1703 ◽  
Author(s):  
J. Beaulieu ◽  
J.-P. Simon
Keyword(s):  
Family Structure ◽  
Mating System ◽  
Natural Populations ◽  
Outcrossing Rate ◽  
The Other ◽  
Single Locus ◽  
White Pine ◽  
Eastern White Pine ◽  
Gene Frequencies ◽  
Self Fertilization

The mating system in two natural eastern white pine (Pinusstrobus L.) populations in Quebec was investigated. These populations contrasted in density and age. The single-locus as well as multilocus outcrossing rate estimates were obtained from four polymorphic enzyme loci using open-pollinated progeny data. The single-locus outcrossing rates ranged from 0.934 to 1.110 with a mean of 1.026 in one population and varied from 0.862 to 1.186 with a mean of 1.007 in the other population. Multilocus estimates exceeded 1.0 in both populations, suggesting the possible absence of self-fertilization. Pollen pool gene frequencies were homogeneous in one population and heterogeneous in the other. The positive or less negative F-values found in the filial populations compared with those observed in the parental populations suggest the presence of a family structure favouring consanguineous matings.

The mating system in natural populations of Thujaorientalis

1991 ◽  
Vol 21 (3) ◽  
pp. 333-339 ◽  
Author(s):  
Chang Yi Xie ◽  
Bruce P. Dancik ◽  
Francis C. Yeh
Keyword(s):  
Mating System ◽  
Expectation Maximization ◽  
Natural Populations ◽  
Expectation Maximization Algorithm ◽  
Outcrossing Rate ◽  
Significant Heterogeneity ◽  
System Parameters ◽  
Marker Loci ◽  
Self Fertilization ◽  
The Mean

EM (expectation–maximization) algorithm procedures were used to estimate mating-system parameters in four natural populations of Thujaorientalis L. from China using seven allozyme marker loci (Fest1, Idh1, Idh2, Mr, Pgi2, Skdh1, and 6Pg2). The mean single-locus outcrossing rate was 0.70 for the species, but estimates showed that there was significant heterogeneity among loci within populations. Multilocus estimates of the outcrossing rate showed that there was significant heterogeneity among populations and among trees within populations. The mean multilocus outcrossing rate (0.75) was higher than the outcrossing rate (0.63) observed in a closely related conifer, Thujaoccidentalis L., but lower than estimates that have been reported for most other conifers. Significant heterozygote deficiencies, relative to Hardy–Weinberg and mating-system equilibria, were observed in all filial populations. In contrast, the maternal populations conformed to Hardy–Weinberg and mating-system equilibria at most loci. Self-fertilization and other forms of inbreeding (e.g., sibling mating) within the sampled populations are important contributors to the low outcrossing estimates in this conifer.

NUMERICAL ANALYSIS OF RANDOM DRIFT IN A CLINE

Genetics ◽  
1980 ◽  
Vol 94 (2) ◽  
pp. 497-517
Author(s):  
Thomas Nagylaki ◽  
Bradley Lucier
Keyword(s):  
Natural Populations ◽  
The Other ◽  
Random Genetic Drift ◽  
Gene Frequencies ◽  
Random Drift ◽  
Linear Habitat ◽  
Asymptotic Formulae ◽  
A Chain ◽  
Average Position ◽  
Uniform Population

ABSTRACT The equilibrium state of a diffusion model for random genetic drift in a cline is analyzed numerically. The monoecious organism occupies an unbounded linear habitat with constant, uniform population density. Migration is homogeneouq symmetric and independent of genotype. A single diallelic locus with a step environment is investigated in the absence of dominance and mutation. The flattening of the expected cline due to random drift is very slight in natural populations. The ratio of the variance of either gene frequency to the product of the expected gene frequencies decreases monotonically to a nonzero constant. The correlation between the gene frequencies at two points decreases monotonically to zero as the separation is increased with the average position fixed; the decrease is asymptotically exponential. The correlation decreases monotonically to a positive constant depending on the separation as the average position increasingly deviates from the center of the cline with the separation fixed. The correlation also decreases monotonically to zero if one of the points is fixed and the other is moved outward in the habitat, the ultimate decrease again being exponential. Some asymptotic formulae are derived analytically.—The loss of an allele favored in an environmental pocket is investigated by simulating a chain of demes exchanging migrants, the other assumptions being the same as above. For most natural populations, provided the allele would be maintained in the population deterministically, this process is too slow to have evolutionary importance.

scholarly journals Mating System and Hybridity in Eucalyptus pauciflora

1977 ◽  
Vol 30 (4) ◽  
pp. 337 ◽  
Author(s):  
MA Phillips ◽  
AHD Brown
Keyword(s):  
Mating System ◽  
Outcrossing Rate ◽  
Seedling Stage ◽  
Average Heterozygosity ◽  
Evolutionary Advantage ◽  
Allozyme Polymorphisms ◽  
Self Fertilization

Allozyme polymorphisms at four loci expressed in seeds, and three other loci expressed in seedlings, were used to determine the outcrossing rate in three natural subalpine populations of snow gum (E. paucijlora). Based on the seed loci data, an estimated 37 % of seed was derived from self-fertilization and 63 % from random outcrossing. In the most elevated population the estimate after germination was similar. However, at lower elevations the frequency of effective self-fertilization estimated at the seedling stage was only 16 %. The less elevated populations also showed a greater average heterozygosity and a larger increase in heterozygosity in the adult over the progeny stages. Heterosis apparently operated differentially in these populations-it was more intense at the lower altitudes. Selection in favour of outcrossed individuals may be an important factor in checking the spread through the population of genes which promote self-fertilization, and which would otherwise enjoy an evolutionary advantage.

Evidence of high self-fertilization in natural populations of eastern white cedar (Thuja occidentalis)

1990 ◽  
Vol 68 (3) ◽  
pp. 663-668 ◽  
Author(s):  
Daniel J. Perry ◽  
Peggy Knowles
Keyword(s):  
Natural Populations ◽  
Outcrossing Rate ◽  
Significant Heterogeneity ◽  
Embryo Survival ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
Northwestern Ontario ◽  
Outcrossing Rates ◽  
Self Fertilization ◽  
Eastern White Cedar

Arrays of open-pollinated seeds were assayed for allozyme polymorphisms at four loci (Mdh-1, Me, 6Pg-2, and Pgm) to obtain estimates of outcrossing rates for three eastern white cedar populations in northwestern Ontario, Canada. Multilocus population outcrossing rate estimates were low, ranging from 0.507 to 0.745, with significant heterogeneity among populations. Low stand densities and relatively high selfed embryo survival may have contributed to the low effective outcrossing rates observed. Single-tree multilocus outcrossing rate estimates were obtained for nine trees from one population. When estimated jointly with outcross pollen pool allele frequencies, these outcrossing rate estimates ranged from 0.253 to 1.023 with significant heterogeneity among trees. Key words: mating system, outcrossing rate, Thuja occidentalis L.

Genetic structure and variability in Pinusstrobus in Quebec

1994 ◽  
Vol 24 (8) ◽  
pp. 1726-1733 ◽  
Author(s):  
J. Beaulieu ◽  
J.-P. Simon
Keyword(s):  
Genetic Diversity ◽  
Statistical Tests ◽  
Natural Populations ◽  
Genetic Distances ◽  
White Pine ◽  
Eastern White Pine ◽  
Improvement Program ◽  
Bonferroni Procedure ◽  
Natural Range ◽  
Very High

The level of genetic diversity of natural populations of eastern white pine (Pinusstrobus L.) from Quebec was estimated from allozyme variants of 18 loci coding 12 enzyme systems. On average, a white pine population was polymorphic at 50.6% of loci, had 1.96 alleles and 1.22 effective alleles per locus, and observed and expected heterozygosities of 0.176 and 0.180, respectively. The level of genetic diversity was lower in the populations of the St. Lawrence lowlands than in those of western Quebec. This observation will help in guiding the selection program of the eastern white pine improvement program under way in Quebec. Genetic differentiation among sampled populations was weak and accounted for only 2% of the total diversity. The estimate of gene flow was very high, resulting in low values for genetic distances among populations. Only one locus showed a heterogeneity of allelic frequencies among populations after the Bonferroni procedure was applied for simultaneous statistical tests. A cluster analysis based on genetic distances among populations revealed that the Anticosti and Abitibi populations, located at the limit of the natural range of white pine, were similar to populations from regions that were geographically the most distant.

HISTOLOGICAL STUDIES OF SYMPTOMS IN SEMIMATURE-TISSUE NEEDLE BLIGHT OF EASTERN WHITE PINE

1967 ◽  
Vol 45 (1) ◽  
pp. 133-143 ◽  
Author(s):  
S. N. Linzon
Keyword(s):  
Pinus Strobus ◽  
Pine Needles ◽  
The Other ◽  
White Pine ◽  
Eastern White Pine ◽  
Histological Studies ◽  
Endodermal Cells ◽  
Needle Blight

The incipient symptoms of needle blight of eastern white pine (Pinus strobus L.) appear only in semimature tissues of current year needles, and the orange-red lesions then spread acropetally throughout adjacent, more mature, tissues. Semimature tissue of white pine needles is characterized by the start of the suberization of the radial and transverse walls of the endodermal cells. The first cells to break down in blighted semimature tissue occur in the mesophyll region of one of the ventral faces of the needle. Mesophyll necrosis spreads laterally to the other ventral face and finally to the dorsal face of the needle, before proceeding distally through mature tissue. Anatomical differences exist between needles collected from susceptible and non-susceptible white pines.

scholarly journals Influences of Conventional and Low-Density Thinning on the Lower Bole Taper and Volume Growth of Eastern White Pine

2011 ◽  
Vol 28 (3) ◽  
pp. 123-128 ◽  
Author(s):  
Christopher H. Guiterman ◽  
Aaron R. Weiskittel ◽  
Robert S. Seymour
Keyword(s):  
Management Practice ◽  
Volume Growth ◽  
The Other ◽  
Low Density ◽  
White Pine ◽  
Eastern White Pine ◽  
Breast Height ◽  
Crown Thinning ◽  
Individual Trees ◽  
Density Treatment

Abstract Throughout the northeastern United States, thinning is a common management practice in stands of eastern white pine (Pinus strobus L.), but foresters lack clear information as to whether conventional B-line or low-density thinning will best achieve their growth and financial objectives. Conventional management consists primarily of light crown thinning, whereas low-density management uses heavy crown thinning to isolate selected crop trees. To better inform silviculturists of the effects of these thinning regimes on volume growth and taper of white pine, we compared the lower bole taper—quantified as Girard form class (GFC)—and volume growth between the two thinning regimes and a nonthinned control. Over the 17-year study period, GFC increased among all treatments from an overall average of 0.77 — 0.01 (—SE) to 0.82 — 0.00. Trees under the B-line thinning regime had the most taper (lowest GFC), owing to a thinning-induced growth response at breast height but not at the top of the butt log. Low-density thinning, on the other hand, resulted in substantially larger, less tapered butt logs with significantly higher growth rates at both breast height and the top of the butt log. The volume growth of low-density trees was significantly higher than that of trees in the other treatments. At the stand level, however, the overall volume growth of the low-density treatment was significantly lower than that of the B-line treatment. Thus, this study reveals that when implementing low-density thinning, there is a tradeoff between overall stand growth and larger, less tapered individual trees.

Pathogenicity of three fungal associates of Hylobiuspales and Pissodesnemorensis (Coleoptera: Curculionidae) to eastern white pine

1992 ◽  
Vol 22 (9) ◽  
pp. 1438-1440 ◽  
Author(s):  
R.J. Nevill ◽  
S.A. Alexander
Keyword(s):  
The Other ◽  
Lesion Length ◽  
Malt Extract ◽  
Perfect State ◽  
White Pine ◽  
Eastern White Pine ◽  
Pine Seedlings ◽  
Blue Stain Fungi ◽  
Blue Stain ◽  
Fungal Associates

The pathogenicity of three fungal associates of the pine reproduction weevils, Hylobiuspales (Hbst) and Pissodesnemorensis Germar, to eastern white pine (Pinusstrobus L.) was investigated. Three-year-old eastern white pine seedlings were inoculated with isolates of Leptographiumprocerum (Kendr.) Wingf., Ophiostomapiceae (Munch) Sydow & Sydow, or a Graphium species that produced no perfect state. The inoculations were made by wounding the seedlings and inserting a block of malt extract agar colonized by the respective fungi into the wounds. After 3 months, the wounds of seedlings inoculated with L. procerum were resinous and there were significantly longer lesions in the bark and sapwood than in seedlings inoculated with the other fungi. Based on reisolation from the xylem, both L. procerum and O. piceae colonized the sapwood beyond lesions or any visual discoloration, but the Graphium species did not. These results confirm the pathogenicity of L. procerum and O. piceae and suggests that lesion length alone does not fully characterize colonization by some blue stain fungi.

scholarly journals Growth of Eastern White Pine (Pinus strobus L.) Related to Forest Floor Consumption by Prescribed Fire in the Southern Appalachians

2002 ◽  
Vol 26 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Katherine J. Elliott ◽  
James M. Vose ◽  
Barton D. Clinton
Keyword(s):  
Forest Floor ◽  
Fire Severity ◽  
The Other ◽  
Size Difference ◽  
Southern Appalachians ◽  
White Pine ◽  
Eastern White Pine ◽  
Growing Seasons ◽  
Humus Layer

Abstract Chainsaw felling, burning, and planting of eastern white pine (Pinus strobusL.) have been prescribed on degraded pine/hardwood stands in the Southern Appalachians to improve overstory composition and productivity. The desired future condition of the overstory is a productive pine/hardwood mixture, with white pine, which is resistant to southern pine beetle (Dendroctonus frontalis), as the dominant pine. We evaluated the growth of white pine planted after fell-and-burn treatments through eight growing seasons after planting on three sites that differed in their fire characteristics and carbon and nitrogen losses. The three sites (JE, JW, and DD) differed in heat penetration and forest floor consumption. Although very little consumption of the Oe+Oa humus layer occurred during burning, consumption of the Oi litter layer was 94%, 94%, and 63% at JE, JW, and DD, respectively. Corresponding to the forest floor layer consumption (Oi and Oe+Oa combined), 46% of forest floor N was lost at JE, 45% of forest floor N was lost at JW, and less than 0.1% of the forest floor N was lost at DD. Biomass and density of woody competitor species were not significantly related to white pine size or growth. By the eighth growing season, no differences in white pine size or growth were detected between JE and JW, but DD had significantly smaller white pine trees. The size difference between DD and the other two sites was attributed to the replanting of seedlings at DD in 1992. However, relative growth rate (RGR) was significantly higher on DD in 1998 than the other two sites. Eight growing seasons after planting, white pine growth was negatively related to percent Oi layer consumed on the JE and JW sites. We also found significant relationships between white pine RGR and percent Oi consumed using data from all three sites. Although fire severity had a long-term effect on pine growth, fire severity was considered low overall on these sites because there were limited losses from the forest floor Oe+Oa layer. However, white pine increment and RGR were significantly related to percent forest floor Oi mass and N loss. This loss of site N capital could have a significant negative effect on growth of planted white pine over the long term. South. J. Appl. For. 26(1):18–25.

Estimates of outcrossing rates in Lathyrus latifolius populations

Genome ◽  
1991 ◽  
Vol 34 (6) ◽  
pp. 988-992 ◽  
Author(s):  
Mary Jo W. Godt ◽  
J. L. Hamrick
Keyword(s):  
Mating System ◽  
Outcrossing Rate ◽  
Single Locus ◽  
Heterozygote Advantage ◽  
Significant Heterogeneity ◽  
Isozyme Markers ◽  
Biparental Inbreeding ◽  
Outcrossing Rates

Isozyme markers were used to estimate parameters of the mating system of Lathyrus latifolius, a bumblebee-pollinated legume. Multilocus outcrossing estimates (mean tm = 0.807; range = 0.702–0.870) differed significantly from random outcrossing. Comparisons of single-locus outcrossing estimates (mean ts = 0.756; range = 0.627–0.852) and multilocus estimates suggested that biparental inbreeding contributed about 21% to the apparent rate of selfing. Significant heterogeneity in outcrossing rates occurred among the seven populations studied. A tendency for selection against inbred individuals, or heterozygote advantage, was apparent in all populations.Key words: mating system, Lathyrus latifolius, outcrossing rate, isozymes, Leguminosae.

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