Estimation of effective population number in aPicea abies(Karst.) seed orchard based on flower assessment

1996 ◽  
Vol 11 (1-4) ◽  
pp. 111-121 ◽  
Author(s):  
Erik D. Kjær
Keyword(s):  
Seed Orchard ◽  
Effective Population ◽  
Population Number

Paternity analysis with microsatellites in a Danish Abies nordmanniana clonal seed orchard reveals dysfunctions

2006 ◽  
Vol 36 (4) ◽  
pp. 1054-1058 ◽  
Author(s):  
O K Hansen ◽  
E D Kjær
Keyword(s):  
Asymptotic Variance ◽  
Seed Orchard ◽  
Paternity Analysis ◽  
Effective Population ◽  
Population Number ◽  
Clonal Seed Orchard ◽  
Relative Contribution ◽  
Male Gametes ◽  
Abies Nordmanniana ◽  
The Status

A paternity analysis using five microsatellite markers was conducted in a Danish clonal seed orchard with 13 Abies nordmanniana (Stev.) Spach clones. The purpose was to investigate potential seed-orchard dysfunctions, with special emphasis on nonequal pollen contributions and selfing. Male paternity was found for 232 seedlings germinated from seeds collected on three ramets, each of eight clones, and the relative contribution of each clone to the gene pool of male gametes was calculated. Furthermore, 49 ramets were genotyped to check for erroneous grafting. The effect of an unbalanced male contribution was quantified by means of two measures: (1) the status number (NS), which reflects buildup of coancestry in the seed-orchard crop as a result of a low number of clones and an unequal male contribution, and (2) the asymptotic variance effective population number (Ne(v)). The contributions by pollen donors from the 13 clones were highly skewed. Three clones were fathers to more than 75% of the progenies, while making up only 24% of the ramets in the seed orchard. Four clones sired no progenies at all. The unequal contribution on the male side corresponded to NS = 4.2 and Ne(v) = 5.8. Some selfing was observed, which may give rise to concern if clonal seed orchards with few clones are established. The estimated maximum pollen contamination from outside the seed orchard was 4.3%. No grafting–labelling errors were identified.

Mating system estimates and effective population numbers for an isolated noble fir (Abiesprocera) clonal seed orchard in Denmark

1996 ◽  
Vol 26 (7) ◽  
pp. 1135-1141 ◽  
Author(s):  
Hans R. Siegismund ◽  
Erik D. Kjær ◽  
Ulrik Bräuner Nielsen
Keyword(s):  
Mating System ◽  
Seed Orchard ◽  
Allele Frequencies ◽  
Homogeneous Distribution ◽  
Effective Population ◽  
Population Number ◽  
Clonal Seed Orchard ◽  
Isozyme Loci ◽  
Noble Fir ◽  
Population Numbers

The mating system of a seed orchard of noble fir (Abiesprocera Rehd.) in Denmark was analyzed, with variation being found at two unlinked isozyme loci. Comparison of allele frequencies in the pollen pool fertilizing the upper and the lower parts of the trees showed a homogeneous distribution. There was no difference in the outcrossing rates estimated for cones harvested at the top and the lowermost branches carrying cones. Both were slightly greater than 1, as was the combined estimate that did not differ significantly from 1. The clones present in the seed orchard are outcrossing, and the allele frequencies found in the pollen pool agree with the frequencies found in the clones of the seed orchard on average. However, the allele frequencies varied significantly between the 20 families, suggesting that the pollen pool has been variable within the seed orchard. The inbreeding and variance effective population numbers were estimated by assuming that the differences in flowering reflected variation in gamete contribution from the clones to the offspring. The inbreeding effective population number was found to be 65% of the total number of clones. The variance effective population number was 121% of the number of clones when it was assumed that a large number of offspring were harvested from every clone.

scholarly journals Advanced genebank management of genetic resources of European wild apple, Malus sylvestris, using genome-wide SNP array data

2021 ◽  
Vol 17 (4) ◽  
Author(s):  
Joukje Buiteveld ◽  
Herma JJ Koehorst-van Putten ◽  
Linda Kodde ◽  
Ivo Laros ◽  
Giorgio Tumino ◽  
...  
Keyword(s):  
Genetic Resources ◽  
Genetic Relationship ◽  
Snp Array ◽  
Seed Orchard ◽  
Effective Population ◽  
Malus Sylvestris ◽  
Genebank Management ◽  
Genetic Resources Management ◽  
Genebank Collection ◽  
Close Genetic Relationship

AbstractThe Netherlands’ field genebank collection of European wild apple (Malus sylvestris), consisting of 115 accessions, was studied in order to determine whether duplicates and mistakes had been introduced, and to develop a strategy to optimize the planting design of the collection as a seed orchard. We used the apple 20K Infinium single nucleotide polymorphism (SNP) array, developed in M. domestica, for the first time for genotyping in M. sylvestris. We could readily detect the clonal copies and unexpected duplicates. Thirty-two M. sylvestris accessions (29%) showed a close genetic relationship (parent-child, full-sib, or half-sib) to another accession, which reflects the small effective population size of the in situ populations. Traces of introgression from M. domestica were only found in 7 individuals. This indicates that pollination preferentially took place among the M. sylvestris trees. We conclude that the collection can be considered as mainly pure M. sylvestris accessions. The results imply that it should be managed as one unit when used for seed production. A bias in allele frequencies in the seeds may be prevented by not harvesting all accessions with a close genetic relationship to the others in the seed orchard. We discuss the value of using the SNP array to elaborate the M. sylvestris genetic resources more in depth, including for phasing the markers in a subset of the accessions, as a first step towards genetic resources management at the level of haplotypes.

scholarly journals EFFECTIVE POPULATION NUMBER IN CEPAEA : A MODIFICATION

Evolution ◽  
1976 ◽  
Vol 30 (1) ◽  
pp. 186-186
Author(s):  
J. J. D. Greenwood
Keyword(s):  
Effective Population ◽  
Population Number

scholarly journals ACCUMULATION OF DELETERIOUS GENES IN A CAGE POPULATION OF DROSOPHILA MELANOGASTER

Genetics ◽  
1977 ◽  
Vol 86 (3) ◽  
pp. 657-664
Author(s):  
Won Ho Lee ◽  
Takao K Watanabe
Keyword(s):  
Drosophila Melanogaster ◽  
Deleterious Effect ◽  
Natural Populations ◽  
Lethal Gene ◽  
Male Sterile ◽  
Effective Population ◽  
Population Number ◽  
Heterozygous Condition ◽  
Cage Population ◽  
Deleterious Genes

ABSTRACT Lethal and sterility mutations were accumulated in a cage population which was initiated with lethal- and sterility-free second chromosomes of D. melanogaster. It took about 2,000 days for the frequencies of these genes to reach equilibrium levels, i.e., 18% lethal and 9% male-sterile chromosomes. Two other cage populations which were initiated with random chromosomes sampled from natural populations and kept for more than eleven years in the laboratory showed 19-20% lethal content. The elimination rates of lethals by homozygosis in these populations were smaller than the mutation rate. By using Nei's formulae, the deleterious effect of a lethal gene in heterozygous condition (h) was estimated to be 0.035. The effective population number in the cage populations was estimated to be 1,000-2,900, while the actual population number was 3,500-7,800.

scholarly journals THE INBREEDING EFFECTIVE POPULATION NUMBER AND THE EXPECTED HOMOZYGOSITY FOR AN X-LINKED LOCUS

Genetics ◽  
1981 ◽  
Vol 97 (3-4) ◽  
pp. 731-737
Author(s):  
Thomas Nagylaki
Keyword(s):  
Genetic Variability ◽  
Joint Action ◽  
Random Mating ◽  
Effective Population ◽  
Random Drift ◽  
Population Number ◽  
Asymptotic Rate ◽  
Large Populations

ABSTRACT Assuming random mating and discrete nonoverlapping generations, the inbreeding effective population number, N(i)  e, is calculated for an X-linked locus. For large populations, the result agrees with the variance effective population number. As an application, the maintenance of genetic variability by the joint action of mutation and random drift is investigated. It is shown that, if every allele mutates at rate u to new types, then the probabilities of identity in state (and hence the expected homozygosity of females) converge to the approximate value (1 + 4N(i)  eu)-1 at the approximate asymptotic rate exp{—[2u + (2N(i)e)-1]t}.

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