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.

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.

Mating system of Racosperma auriculiforme in a seed production area in Zaire

1993 ◽  
Vol 71 (6) ◽  
pp. 779-785 ◽  
Author(s):  
P. Damase Khasa ◽  
William M. Cheliak ◽  
Jean Bousquet
Keyword(s):  
Mating System ◽  
Seed Production ◽  
Random Mating ◽  
Single Locus ◽  
Acacia Auriculiformis ◽  
Mixed Mating ◽  
Outcrossing Rates ◽  
Production Area ◽  
Mixed Mating Model ◽  
Mating Model

Analysis of the mating system of Racosperma auriculiforme (formerly Acacia auriculiformis) in a seed production area in Zaire was conducted using a mixed mating model at five polymorphic loci (Est-2, Est-3, G6p-dh, Nadhdh-2, Pgm-1). Single-locus estimates of outcrossing rate varied widely between 0.615 and 1.204 and were significantly heterogenous among and within the stands. Weighted means of single-locus estimates of outcrossing rates (ts) ranged from 0.859 to 1.032 while multilocus estimates of outcrossing rates (tm) ranged from 0.863 to 1.059. Comparisons between the single-locus estimates and the multilocus estimates of outcrossing rates indicated that most of the inbreeding detected was due to consanguineous (sibling) matings rather than selfing. Comparisons of observed and expected inbreeding coefficients indicated a general deficit of heterozygotes over the frequencies expected from random mating in the single stands and the pooled stands. Locus to locus variation in outcrossing rates suggested that violation of the mixed mating model might have occurred. Implications for seed production, collection, and distribution for reforestation are discussed. Key words: Acacia, mating system, Racosperma, seed production area, Zaire.

Study on Mating System of Pinus koraiensis in Natural Population Based on cpSSR Technology

2011 ◽  
Vol 183-185 ◽  
pp. 700-704 ◽  
Author(s):  
Fu Juan Feng ◽  
Dan Zhao ◽  
Xin Sui ◽  
Xiao Yan Sun
Keyword(s):  
Mating System ◽  
Simple Sequence Repeat ◽  
High Stability ◽  
Mating Systems ◽  
Population Based ◽  
Outcrossing Rate ◽  
Single Locus ◽  
Pinus Koraiensis ◽  
Sequence Repeat ◽  
Simple Sequence

Chloroplast simple sequence repeat (cpSSR) technique was firstly used to study mating system of natural Pinus koraiensis population. Nine pairs of primers with clear spectrum bands, high stability and polymorphism were selected from 70 pairs of cpSSR primers to analyze the mating systems of 28 individuals. 14 polymorphic loci were detected in the nine pairs of primers. The multi-locus (tm) and single-locus (ts) outcrossing rate were 0.966 (SD=0.000) and 0.939 (SD=0.000), respectively, which were slightly higher than those of other tree species. The constant index (F=-0.035) was below zero, indicating the occurrence of excessive heterozygote. Moreover, inbreeding index (tm-ts=0.027; SD=0.000) was close to zero, indicating an insignificant inbreeding. MLDT analysis showed that multi-locus outcrossing rate differed from single-locus outcrossing rate in mating systems of 28 individuals, but the differences were not statistically significant.

scholarly journals Mixed Mating With Preferential Outcrossing in Acacia saligna (Labill.) H. Wendl. (Leguminosae: Mimosoideae)

2008 ◽  
Vol 57 (1-6) ◽  
pp. 139-145 ◽  
Author(s):  
N. George ◽  
M. Byrne ◽  
G. Yan
Keyword(s):  
Mating System ◽  
Breeding System ◽  
Outcrossing Rate ◽  
Basic Knowledge ◽  
Mixed Mating ◽  
Acacia Saligna ◽  
Outcrossing Rates ◽  
Agricultural Regions

Abstract Acacia saligna is being developed as an agroforestry crop for the southern agricultural regions of Australia. This study investigated the breeding system of A. saligna to generate basic knowledge for breeding and utilization of the species. Allozyme markers were used to investigate the mating system of four populations of the species. All the populations had high outcrossing rates, with a mean multilocus outcrossing rate of 0.91. The implications of a highly outcrossed mating system to the utilization of A. saligna are discussed.

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.

scholarly journals Assessing the genetic structure of Oryza glumaepatula populations with isozyme markers

2008 ◽  
Vol 51 (5) ◽  
pp. 873-882 ◽  
Author(s):  
Elizabeth Ann Veasey ◽  
Daruska Cardin ◽  
Rainério Meireles Silva ◽  
Eduardo de Andrade Bressan ◽  
Roland Vencovsky
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Mating System ◽  
Outcrossing Rate ◽  
Structure Parameters ◽  
Mato Grosso ◽  
Isozyme Markers ◽  
Self Fertilization ◽  
Oryza Glumaepatula

To assess the genetic diversity and genetic structure parameters, nine populations of Oryza glumaepatula from the Amazon biome, four from the Pantanal biome, and one collected at Rio Xingu, Mato Grosso, totaling 14 populations and 333 individuals were studied with isozyme markers. Six loci were evaluated showing a moderate allozyme variability (A = 1.21, P = 20.7%, Ho = 0.005, He = 0.060). The populations from the Pantanal biome showed higher diversity levels than the Amazon biome. High genetic differentiation among the populations, expected for self-fertilizing species, was observed (F ST=0.763), with lower differentiation found among the Pantanal populations (F ST=0.501). The average apparent outcrossing rate was higher for the Pantanal populations (t a = 0.092) than for the Amazonian populations (t a = 0.003), while the average for the 14 populations was 0.047, in accordance with a self-fertilization mating system.

Inferring Recent Outcrossing Rates Using Multilocus Individual Heterozygosity: Application to Evolving Wheat Populations

Genetics ◽  
2000 ◽  
Vol 156 (4) ◽  
pp. 1973-1982
Author(s):  
Jérôme Enjalbert ◽  
Jacques L David
Keyword(s):  
Maximum Likelihood ◽  
Temporal Variation ◽  
Mating System ◽  
Outcrossing Rate ◽  
Outcrossing Rates ◽  
Progeny Analysis ◽  
Ml Estimator ◽  
Two Populations

Abstract Using multilocus individual heterozygosity, a method is developed to estimate the outcrossing rates of a population over a few previous generations. Considering that individuals originate either from outcrossing or from n successive selfing generations from an outbred ancestor, a maximum-likelihood (ML) estimator is described that gives estimates of past outcrossing rates in terms of proportions of individuals with different n values. Heterozygosities at several unlinked codominant loci are used to assign n values to each individual. This method also allows a test of whether populations are in inbreeding equilibrium. The estimator’s reliability was checked using simulations for different mating histories. We show that this ML estimator can provide estimates of outcrossing rates for the final generation outcrossing rate (t0) and a mean of the preceding rates (tp) and can detect major temporal variation in the mating system. The method is most efficient for low to intermediate outcrossing levels. Applied to nine populations of wheat, this method gave estimates of t0 and tp. These estimates confirmed the absence of outcrossing (t0 = 0) in the two populations subjected to manual selfing. For free-mating wheat populations, it detected lower final generation outcrossing rates (t0 = 0-0.06) than those expected from global heterozygosity (t = 0.02-0.09). This estimator appears to be a new and efficient way to describe the multilocus heterozygosity of a population, complementary to Fis and progeny analysis approaches.

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.

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.

Mating system and genetic structure of two populations of white spruce (Picea glauca) in eastern Newfoundland

1990 ◽  
Vol 68 (8) ◽  
pp. 1661-1666 ◽  
Author(s):  
David J. Innes ◽  
Gordon G. Ringius
Keyword(s):  
Mating System ◽  
Picea Glauca ◽  
White Spruce ◽  
Allozyme Variation ◽  
Outcrossing Rate ◽  
Single Locus ◽  
Average Value ◽  
Exposed Population ◽  
Habitat Differences ◽  
Two Populations

Allozyme variation at four polymorphic enzyme loci (Pgi-1, Pgi-2, Pgm, Gdh) was used to study genetic variation and mating system in a sheltered (inland) and an adjacent exposed population (coast) of white spruce (Picea glauca (Moench) Voss) in eastern Newfoundland. Despite habitat differences, the two populations showed only small differences in allele frequency for the maternal trees, their progeny, and the estimated pollen pool. Three of the four single-locus estimates of outcrossing rate (ts) for the inland population were significantly less that t = 1.00, with an average value of ts = 0.81. Two of the four single-locus estimates of outcrossing rate in the coast population were significantly less than t = 1.00 and the average for the four loci was 0.71. The multilocus estimates of outcrossing rate (tm) for the inland and coast populations were 0.76 and 0.70, respectively, and both estimates were significantly less than t = 1.00. This level of selfing is higher than that observed for most other conifer species. Key words: genetics, mating system, population genetics, outcrossing, selfing, white spruce.

Sign in / Sign up

Export Citation Format

Share Document