The mating system in a black spruce clonal seed orchard

1987 ◽  
Vol 17 (5) ◽  
pp. 379-382 ◽  
Author(s):  
J. W. Barrett ◽  
P. Knowles ◽  
W. M. Cheliak
Keyword(s):  
Mating System ◽  
Population Size ◽  
Effective Population Size ◽  
Gene Pool ◽  
Black Spruce ◽  
Seed Orchard ◽  
Effective Population ◽  
Isozyme Markers ◽  
Clonal Seed Orchard ◽  
Mating Population

Isozyme markers were used to study the mating system, estimate the effective population size, and determine the effective gene pool composition in a black spruce clonal seed orchard. Ten seeds per family were electrophoretically analyzed by embryo and megagametophytic pairs to determine their allelic and genotypic frequencies at five polymorphic loci. Single-locus estimates of outcrossing ranged from 0.682 to 1.087 (mean, 0.942), while the multilocus estimate was 0.837. The variance effective population size was calculated to be 17 individuals, comprising 13 receptive females and 4 effective males. Evidence of gene pool heterogeneity suggested a small, nonrandomly mating population within the clonal seed orchard.

Development of flowering and the effect of pruning in a clonal seed orchard of lodgepole pine

1994 ◽  
Vol 24 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Anders Fries
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Lodgepole Pine ◽  
Seed Orchard ◽  
Effective Population ◽  
Clonal Seed Orchard ◽  
Crown Volume ◽  
Female Flowering ◽  
Male Strobili

The development of female and male flowering among 20 clones was studied in a clonal seed orchard of lodgepole pine (Pinuscontorta var. latifolia Engelm.) in central Sweden. Flowering in relation to height, crown volume, and pruning was also studied. Twelve years after grafting (7 years after field planting), female flowering averaged 43 strobili per graft while male strobili were few. Eighteen years from grafting, the number of female and male strobuli were 143 and 142, respectively. The female effective population size was around 80% of maximum and was stable during the whole period. The male effective population size increased from 25 to 68%. Index of monoecy increased from 58 to 81% of maximum. The results indicate that at around 18 years after grafting, female and male flowering were satisfactorily distributed among the clones. There were no clonal correlations between male flowering and female flowering, while correlations between years for those traits separately were strong. Male flowering showed stronger correlation to the size of the graft than female flowering.

scholarly journals Clonal fertility variation and its effects on the effective population size in the seed orchard of dioecious species, Fraxinus rhynchophylla

2012 ◽  
Vol 61 (1-6) ◽  
pp. 79-84
Author(s):  
Kyu-Suk Kang ◽  
Chang-Soo Kim
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Gene Pool ◽  
Gene Diversity ◽  
Seed Orchard ◽  
Effective Population ◽  
Dioecious Species ◽  
Theoretical Approaches ◽  
Fertility Variation ◽  
Male Flowers

Abstract The numbers of female and male flowers were assessed in a clonal seed orchard of Fraxinus rhynchophylla for four consecutive years from 2004 through 2007. The female and male flowers of the grafts from 48 clones were counted individually over the crown. Fertility variation was calculated by sibling coefficient that is related to the coefficient of variation in parental flower assessment. Estimated maternal and paternal fertilities were not constant but varied from year to year, and they were also found to be weakly correlated. The effective numbers of clones serving as male and female parents were calculated from the sibling coefficients of maternity and paternity. We applied two theoretical approaches to estimate the clonal effective population sizes based on 1) fertility variation (i.e., effective number of parents, N(c)) and 2) gender balance (effective population size, Nee) among parental genotypes. The values of Ne(c) were higher in the years with abundant flowering and seed production, while sibling coefficients were lower. On average (pooled), the maternal, paternal and clonal values of Ne(c) were calculated to be 17.3, 21.0 and 38.1 respectively. The Ne(c) for maternal gamete gene pool was ranged from 9.8 to 16.7. The values of Ne for paternal gamete gene pool were generally higher (ranged from 14.9 to 21.9) than those for maternal. When pooled, the Ne was 47.2 and the values of Ne were higher when the gender ratio was more balanced. An option of equal seed harvest might be good to mitigate fertility variation and to improve gene diversity of seeds.

scholarly journals Effective population size estimation in seed orchards: A case study of Pinus nigra ARNOLD and Fraxinus excelsior L./ F. angustifolia VAHL.

Genetika ◽  
2013 ◽  
Vol 45 (2) ◽  
pp. 575-588 ◽  
Author(s):  
Eva Machanská ◽  
Vladimír Bajcar ◽  
Roman Longauer ◽  
Dusan Gömöry
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Seed Orchard ◽  
Pinus Nigra ◽  
Fraxinus Excelsior ◽  
Effective Population ◽  
Female Fecundity ◽  
Male And Female ◽  
Status Number ◽  
Relative Status

Effective population size as a parameter closely correlating with the genetic and genotypic diversity of the seed orchard output is an important indicator of seed orchard functioning. It is determined by the variation of male and female gametic contributions of parental genotypes (including those outside the seed orchard), influenced by the variation in male and female gamete production, reproductive phenology, pollen dispersal within seed orchard and other factors. We assessed male and female fecundity, as well as temporal course of male and female flowering in two seed orchards of Pinus nigra ARNOLD and Fraxinus excelsior L./F. angustifolia VAHL. in Slovakia. In both cases, male and female gametic contributions of plus-tree clones were modeled on the basis of fecundity and flowering phenology, and were used to calculate status number as an estimator of effective population size. In the seed orchard of Pinus nigra, marker-aided verification of clonal fidelity revealed unexpectedly high proportion of misplaced ramets (29.9%) and alien genotypes (44.4%). Monitoring of reproductive processes in 2002 and 2003 showed high variation in both male and female fecundity, and pollen shedding preceding female receptivity in Pinus nigra. All these factors contributed to a very low relative status effective number, representing 8.6% to 38.6% of the population census (depending from the management option in relation to misplaced and alien genotypes). In the mixed seed orchard of Fraxinus excelsior and F. angustifolia, the proportion of misplaced and alien genotypes was much lower (22.4% and 12.3%, respectively). However, a high fecundity variation and protogyny resulted in a low relative status number (18.8% to 29.5% of the census number of clones) also in this seed orchard. Practical implications of these findings are shortly discussed and practical management options are proposed.

scholarly journals SNP-based analysis reveals unexpected features of genetic diversity, parental contributions and pollen contamination in a white spruce breeding program

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Esteban Galeano ◽  
Jean Bousquet ◽  
Barb R. Thomas
Keyword(s):  
Genetic Diversity ◽  
Population Size ◽  
Effective Population Size ◽  
White Spruce ◽  
Seed Orchard ◽  
Pedigree Reconstruction ◽  
Effective Population ◽  
Pollen Contamination ◽  
Contamination Levels ◽  
The Impact

AbstractAccurate monitoring of genetic diversity levels of seedlots and mating patterns of parents from seed orchards are crucial to ensure that tree breeding programs are long-lasting and will deliver anticipated genetic gains. We used SNP genotyping to characterize founder trees, five bulk seed orchard seedlots, and trees from progeny trials to assess pollen contamination and the impact of severe roguing on genetic diversity and parental contributions in a first-generation open-pollinated white spruce clonal seed orchard. After severe roguing (eliminating 65% of the seed orchard trees), we found a slight reduction in the Shannon Index and a slightly negative inbreeding coefficient, but a sharp decrease in effective population size (eightfold) concomitant with sharp increase in coancestry (eightfold). Pedigree reconstruction showed unequal parental contributions across years with pollen contamination levels between 12 and 51% (average 27%) among seedlots, and 7–68% (average 30%) among individual genotypes within a seedlot. These contamination levels were not correlated with estimates obtained using pollen flight traps. Levels of pollen contamination also showed a Pearson’s correlation of 0.92 with wind direction, likely from a pollen source 1 km away from the orchard under study. The achievement of 5% genetic gain in height at rotation through eliminating two-thirds of the orchard thus generated a loss in genetic diversity as determined by the reduction in effective population size. The use of genomic profiles revealed the considerable impact of roguing on genetic diversity, and pedigree reconstruction of full-sib families showed the unanticipated impact of pollen contamination from a previously unconsidered source.

scholarly journals Clonal Variation in Acorn Production and its Effect on the Effective Population Size in a Quercus acutissima Seed Orchard

2010 ◽  
Vol 59 (1-6) ◽  
pp. 170-175 ◽  
Author(s):  
K. S. Kang ◽  
C. S. Kim ◽  
Y. A. El-Kassaby
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Rank Correlation ◽  
Correlation Coefficients ◽  
Seed Orchard ◽  
Clonal Variation ◽  
Effective Population ◽  
Acorn Production ◽  
Quercus Acutissima ◽  
Clone Size

Abstract Acorn production was surveyed for eight consecutive years (2000-2007) in a 94-clone Sawtooth oak (Quercus acutissima) seed orchard established in 1992. Acorn production commenced in 2000 and peaked in 2005 and was characterized by a 3-4 years interval. Sixty out of the orchard’s 94 clones were consistent producers across the study period. Acorn production’s Pearson productmoment and Spearman rank correlation coefficients were significant and consistently positive over the eight years study period. Parental cumulative reproductive output, represented by parental balance curves, slightly varied among mast years and showed steady improvement (less distortion) over years. Effective population size (Np) was high in moderate and good acorn production years; however, departure from clonal equal contribution was observed throughout the study period. Parental effective population size was estimated under various scenarios of male fecundity (pollen production is: 1) proportional to clone size, 2) equal to female contribution, and 3) equal across all clones) resulted in high Np and low group co-ancestry under equal male fecundity scenario while moderate Np size and group co-ancestry were observed when male fecundity was assumed to be proportional to clone size (i.e., ramet number).

EFEKTYWNA WIELKOŚĆ POPULACJI – ZNACZENIE W OCHRONIE ZASOBÓW GENOWYCH

2020 ◽  
Vol XIII ◽  
pp. 1-1
Author(s):  
Magdalena Trojankiewicz
Keyword(s):  
Mathematical Model ◽  
Population Size ◽  
Effective Population Size ◽  
Conservation Biology ◽  
Gene Pool ◽  
Next Generation ◽  
Effective Population

The paper describes the effective population size and its importance in the protection of gene resources in conservation biology. The concept of effective population size has been introduced as a mathematical model, which is enriched with many additional factors that can affect the change of the gene pool of the next generation. Depending on the type of effective population size, the results obtained may vary, for example, the inbreeding effective population size and the variance effective population size.

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