1 Department of Phytology, Technical University in Zvolen, Zvolen, Slovakia

1. Factors affecting effective population size estimation in a seed orchard: a case study of Pinus sylvestris Dušan Gömöry1, Roman Longauer2, Ladislav Paule1, Rudolf Bruchánik3 1Department of Phytology, Technical University in Zvolen, Zvolen, Slovakia 2National Forestry Centre, Forestry Research Institute , Zvolen, Slovakia 3State Forests of the Slovak Republic, General Directorate, Banská Bystrica, Slovakia

2. Ideal seed orchard: Randomly mating Mendelian population Contribution of genotypes to male and female gamete pools proportionate to their frequencies No change of allelic frequencies over generations

3. Real clonal seed orchards of European conifers: Marker studies: Generally no or small deviations of genotypic frequencies from HWE expectations Low levels of self-fertilization but (1) Sometimes significant differences in allelic frequencies between seed orchard and the crop but (2) Marker studies cannot easily be done everywhere

4. Ideal clonal seed orchard: • Equal contribution of parental clones • to the gene pool of the seed crop • Reality: • Deviations from equal contribution because of: • unequal female gamete contributions • unequal male gamete contributions • phenological isolation • pollen dispersal in space (distribution of clones – • distance-dependent dispersal, wind direction, • turbulences) • genetic incompatibilities

5. Consequences: • loss of genetic diversity in seed orchard crops • increased coancestry (potentially higher • inbreeding in the following generation) • Monitoring the genetic diversity in seed • orchard crops: • Effective population size (e.g. effective number • of clones) • Status number (Lindgren et al. 1996: • Silvae Genet. 45: 52–59). • NS= 0.5/Θ • = number of unrelated non-inbred genotypes • having the same average coancestry as • the considered population

6. Case study: three Scots pine seed orchards

7. Assessed characteristics (for each ramet): Female gamete contribution – cone weighting Male gamete contribution – counting and size assessment of male strobili Flowering phenology: 3 dates in Háj and Sýkorová, 5 dates in Kolkáreň, 5 developmental stages for male strobili, 6 stages for female strobili Spatial dispersal of pollen: negative exponential dispersal function (Adams & Birkes 1991)

8. Alien genotypes present in all three seed orchards (rootstocks with aborted scions, • unregistered clones, …) as proved by allozyme genotyping • Three situations considered: • Alien material removed • Alien ramets not removed but not • harvested • (3) Cones harvested from all ramets

9. Effective number, status number and coancestry estimates F – female contributions assessed, M –male contributions assessed, P – phenology assessed, D – pollen flow considered

10. Effective number, status number and coancestry estimates Háj

11. Effective number, status number and coancestry estimates F – female contributions assessed, M –male contributions assessed, P – phenology assessed, D – pollen flow considered

12. Effective number, status number and coancestry estimates Sýkorová

13. Effective number, status number and coancestry estimates F – female contributions assessed, M –male contributions assessed, P – phenology assessed, D – pollen flow considered

14. Effective number, status number and coancestry estimates Kolkáreň

15. Conclusions • In old, fully fructificating seed orchards of Scots pine in Central Europe, effective number of clones is a sufficient estimator of the effective population size • Phenology and spatially-dependent pollen dispersal do not considerably affect NS estimates and need not be assessed for practical purposes • Young seed orchard are unbalanced and phenologically not synchronized, consequently, effective number of clones is a poor estimator of effective size and status number is affected by all factors (male + female fertility, phenology, spatial design)

16. Thank you for your attention