Biodiversity & Conservation

, Volume 5, Issue 6, pp 795–813 | Cite as

Impact of selection and breeding on the genetic diversity in Douglas-fir

  • Yousry A. El-Kassaby
  • Kermit Ritland

Genetic changes following domestication of Douglas-fir were studied using isozyme data derived from two generations of seed orchards and their 49 wild progenitor populations. In addition, the breeding, production, and infusion populations used in the seed orchards were compared to their wild counterparts. Several parameters of gene diversity were measured (number of alleles per locus Na, per cent of polymorphic loci PLP, and expected heterozygosity H, and population divergence D). These measures were similar or higher in the domesticated populations compared to their natural progenitors, indicating that early selection and breeding of a highly polymorphic species does not significantly reduce genetic variation. The two generations of seed orchards also did not differ, indicating that genetic variation may remain stable over future generations of forest plantations. Interestingly, compared to the natural populations, heterozygosity was higher in the seed orchards, probably due to pooling of widely distributed natural populations; however, rare localized or private alleles seemed to be less frequent in the domesticated populations. Differentiation values were not significant between the first generation orchards and the natural populations, but significant differences were observed between the second generation orchards and the wild progenitor populations, probably due to the interbreeding that forms the advanced generation seed orchards.


genetic diversity Douglas-fir isozymes natural breeding production populations 


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  1. Aspit V.J., Nakamura R.R. and Wheeler N.C. (1989) Differential male reproductive success in Douglas-fir. Theor. Appl. Genet. 77, 681–4.Google Scholar
  2. Bergmann F. and Ruetz W. (1991) Isozyme genetic variation and heterozygosity in random tree samples and selected orchard clones from the same Norway spruce populations. For. Ecol. Manage. 46, 39–47.Google Scholar
  3. Brown A.H.D. (1978) Isozymes, plant population genetic structure and genetic conservation. Theor. Appl. Genet. 52, 145–57.Google Scholar
  4. Brown A.H.D. and Clegg M.T. (1983) Isozyme assessment of plant genetic resources. In Isozymes: Current Topics in Biology and Medical Research, Vol. II (M.C. Rattazzi, J.G. Scandalios and G.S. Whitt, eds.) pp. 285–95. New York: Alan R. Liss.Google Scholar
  5. Brunel D. and Rodolphe F. (1985) Genetic neighbourhood structure in a population of Picea abies L. Theor. Appl. Genet. 71, 101–10.Google Scholar
  6. Burdon R.D. (1988) Recruitment for breeding populations: objectives, genetics, and implementation. In Proc. of the 2nd Inter. Conf. on quantitative genetics (B.S. Weir, E.J. Eisen, M.M. Goodman and G. Namkoong, eds) pp. 555–72. Sunderland, MA: Sinauer Associates Inc. Publishers.Google Scholar
  7. Chaisurisri K. and El-Kassaby Y.A. (1994) Genetic diversity in a seed production population vs natural populations of Sitka spruce. Biodiv. Conserv. 3, 512–23.Google Scholar
  8. Copes D.L. and Sniezko R.A. (1991) The influence of floral bud phenology on the potential mating system of a wind-pollinated Douglas-fir orchard. Can. J. For. Res. 21, 813–20.Google Scholar
  9. Cathbert J.R. (1992) Forest renewal: the foundation for enhanced forest stewardship. In The Silviculture Conference: Stewardship in the New Forest (C. Boisvert and L. Grant, Chair and Coordinator) pp. 306–11. Ontario: Forestry Canada, Ottawa.Google Scholar
  10. El-Kassaby Y.A. (1991) Genetic variation within and among conifer populations: review and evaluation of methods. In Biochemical markers in population genetics of forest trees (H.H. Hattemer, S. Fineschi, F. Cannata and M.E. Malvolti, eds) pp. 59–74. The Hague. SPB Academic Publishing bv.Google Scholar
  11. El-Kassaby Y.A. and Askew G.R. (1991) The relation between reproductive phenology and output in determining the gametic pool profile in a Douglas-fir seed orchard. For. Sci. 37, 827–35.Google Scholar
  12. El-Kassaby Y.A. and Cook C. (1994) Female reproductive energy and reproductive success in a Douglas-fir seed orchard and its impact on genetic diversity. Silvae Genet. 43, 243–6.Google Scholar
  13. El-Kassaby Y.A. and Davidson R. (1991) Impact of pollination environment manipulation on the apparent outcrossing rate in a Douglas-fir seed orchard. Heredity 66, 55–9.Google Scholar
  14. El-Kassaby Y.A. and Namkoong G. (1994) Impact of forest management practices on genetic diversity and its conservation. In Proc. International Symposium on Genetic Conservation and Production of Tropical Forest Tree Seed (R.M. Drysdale, S.E.T. John and A.C. Yapa, eds) pp. 205–13. Saraburi, Thailand: ASEAN-CANADA Forest Tree Seed Centre Project, Muak-Lek.Google Scholar
  15. El-Kassaby Y.A. and Ritland K. (1992) Frequency-dependent male reproductive success in a polycross of Douglas-fir. Theor. Appl. Genet. 83, 752–8.Google Scholar
  16. El-Kassaby Y.A. and Ritland K. (1996) Genetic variation in low elevation Douglas-fir of British Columbia and its relevance to gene conservation. Biodiv. Conserv. 6, 779–794.Google Scholar
  17. El-Kassaby Y.A. and Sziklai O. (1982) Genetic variation of allozyme and quantitative traits in a selected Douglas-fir [Pseudotsuga menziesii var. menziesii (Mirb.) Franco] population. For. Ecol. Manage. 4, 115–26.Google Scholar
  18. El-Kassaby Y.A., Yeh F.C. and Sziklai O. (1981) Estimation of the outcrossing rate of Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] using allozyme polymorphism. Silvae Genet. 30, 182–4.Google Scholar
  19. El-Kassaby Y.A., Meagher M.D., Parkinson J. and Portlock F.T. (1987) Allozyme inheritance, heterozygosity and outcrossing rate among Pinus monticola near ladysmith, British Columbia. Heredity 58, 173–81.Google Scholar
  20. El-Kassaby Y.A., Ritland K., Fashler A.M.K. and Devitt W.J.B. (1988) The role of reproductive phenology upon the mating structure of a Douglas-fir seed orchard. Silvae Genet. 37, 76–82.Google Scholar
  21. El-Kassaby Y.A., Fashler A.M.K. and Crown M. (1989) Variation in fruitfulness in a Douglas-fir seed orchard and its effect on crop management decisions. Silvae Genet. 38, 113–21.Google Scholar
  22. El-Kassaby, Y.A., Barker, J.E. and Dunsworth, B.G. (1994) Conservation of forest genetic resources — British Columbia's coastal industry perspectives. In Conservation of Forest Genetic Resources Workshop, November 1993. Toronto: in press.Google Scholar
  23. Ellstrand N.C. and Marshall D.L. (1985) The impacts of domestication on distribution of allozyme variation within and among cultivars of radish, Raphanus sativus L. Theor. Appl. Genet. 69, 393–8.Google Scholar
  24. Erickson V.J. and Adams T.W. (1989) Mating success in a coastal Douglas-fir seed orchard as affected by distance and floral phenology. Can. J. For. Res. 19, 1248–55.Google Scholar
  25. Francis C.A. (1981) Development of plant genotypes for multiple cropping systems. In Plant Breeding II (K.J. Frey, ed.) pp. 179–231. Ames: The Iowa State University Press.Google Scholar
  26. Hamrick J.L., Godt M.J.W. and Sherman-Broyles S.L. (1992) Factors influencing levels of genetic diversity in woody plant species. New For. 6, 95–124.Google Scholar
  27. Heaman, J.C. (1985) A breeding program in the coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). In Proc. 18th Can. Tree Improv. Assoc. Part I (C.W. Yeatman and T.J.B. Boyle, eds.) pp. 186–8.Google Scholar
  28. Levin D.A. (1976) Consequences of long-term artificial selection, inbreeding and isolation in Phlox. 2. The organization of allozymic variability. Evolution 30, 463–72.Google Scholar
  29. Li P. and Adams W.T. (1989) Range-wide patterns of allozyme variation in Douglas-fir (Pseudotsuga menziesii). Can. J. For. Res. 19, 149–61.Google Scholar
  30. Markel S.A. and Adams W.T. (1987) Patterns of allozyme variation within and among Douglas-fir breeding zones in southwest Oregon. Can. J. For. Res. 17, 402–7.Google Scholar
  31. Marshall D.R. and Brown A.H.D. (1975) Optimum sampling strategies in genetic conservation. In Crop genetic resources for today and tomorrow (O.H. Frankel and J.G. Hawkes, eds) pp. 53–80. London: Cambridge University Press.Google Scholar
  32. Millar C.I. and Marshall K.A. (1991) Allozyme variation of Port-Orford-cedar (Chamaecyparis lawsoniana): implications for genetic conservation. For. Sci. 37, 1060–77.Google Scholar
  33. Moran G.F. and Adams W.T. (1989) Microgeographical patterns of allozyme differentiation in Douglas-fir from southwest Oregon. For. Sci. 35, 3–15.Google Scholar
  34. Mouna O. (1989) Population genetics in forest tree improvement. In Plant population genetics, breeding and genetic resources (A.H.D. Brown, M.T. Clegg, A.L. Kahler and B.S. Weir, eds) pp. 282–98. Sunderland, MA: Sinauer Associates Inc. Publishers.Google Scholar
  35. Müller-Starck G. (1987) Genetic differentiation among seed samples from provenances of Pinus sylvestris. Silvae Genet. 36, 232–8.Google Scholar
  36. Nakamura R.R. and Wheeler N.C. (1992) Pollen competition and parental success in Douglas-fir. Evolution 46, 846–51.Google Scholar
  37. Namkoong, G. (1994) Genetic diversity for forest policy and management. In Measuring biodiversity for forest policy and management workshop. Feb., 1994, Vancouver: in press.Google Scholar
  38. Neale D.B. and Adams W.T. (1985) The mating system in natural and shelterwood stands of Douglas-fir. Theor. Appl. Genet. 71, 201–7.Google Scholar
  39. Nei M. (1973) Analysis of gene diversity in subdivided populations. Proc. Natl. Acad. Sci. USA 70. 3321–3.Google Scholar
  40. Nei M. and Roychoudhury A.K. (1974) Sampling variances of heterozygosity and genetic distance. Genetics, 76, 379–90.Google Scholar
  41. Reynolds S. and El-Kassaby Y.A. (1990) Parental balance in a Douglas-fir seed orchard: cone vs seed production. Silvae Genet. 39, 40–2.Google Scholar
  42. Ritland K. and El-Kassaby Y.A. (1985) The nature of inbreeding in a seed orchard of Douglas-fir as shown by an efficient multilocus model. Theor. Appl. Genet. 71, 375–84.Google Scholar
  43. Roberds J.H., Friedman S.T. and El-Kassaby Y.A. (1991) Effective number of pollen parents in clonal seed orchards. Theor. Appl. Genet. 82, 313–20.Google Scholar
  44. Savolainen O. and Karkkainen K. (1992) Effect of forest management on gene pools. New For. 6. 329–45.Google Scholar
  45. Savolainen O. and Yazdani R. (1991) Genetic comparison of natural and artificial populations of Pinus sylvestris. In Genetic Variation in European Populations of Forest Trees (G. Müller-Starck and M. Ziehe, eds) pp. 228–34. Frankfurt am Main: Sauerländer's Verlag.Google Scholar
  46. Shaw D.V. and Allard R.W. (1982) Estimation of outcrossing rates in Douglas-fir using isozyme markers. Theor. Appl. Genet. 62, 113–20.Google Scholar
  47. Wright S. (1965) The interpretation of population structure in F-statistics with special regard to systems of mating. Evolution 19, 395–420.Google Scholar
  48. Yeh F.C. and O'Malley D.M. (1980) Enzyme variation in natural populations of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, from British Columbia. I. genetic variation patterns in coastal populations. Silvae Genet. 29, 83–92.Google Scholar
  49. Yeh F.C. and Morgan K. (1987) Mating system and multilocus associations in a natural population of Pseudotsuga menziesii (Mirb.) Franco. Theor. Appl. Genet. 73, 799–808.Google Scholar

Copyright information

© Chapman & Hall 1996

Authors and Affiliations

  • Yousry A. El-Kassaby
    • 1
    • 2
  • Kermit Ritland
    • 3
  1. 1.Pacific Forest Products LimitedSaanich Forestry CentreSaanichtonCanada
  2. 2.Faculty of ForestryUniversity of British ColumbiaVancouverCanada
  3. 3.Department of BotanyUniversity of TorontoCanada

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