Theoretical and Applied Genetics

, Volume 108, Issue 6, pp 1162–1171 | Cite as

Effects of inbreeding on coastal Douglas fir growth and yield in operational plantations: a model-based approach

  • Tongli WangEmail author
  • Sally N. Aitken
  • Jack H. Woods
  • Ken Polsson
  • Steen Magnussen
Original Paper


In advanced generation seed orchards, tradeoffs exist between genetic gain obtained by selecting the best related individuals for seed orchard populations, and potential losses due to subsequent inbreeding between these individuals. Although inbreeding depression for growth rate is strong in most forest tree species at the individual tree level, the effect of a small proportion of inbreds in seed lots on final stand yield may be less important. The effects of inbreeding on wood production of mature stands cannot be assessed empirically in the short term, thus such effects were simulated for coastal Douglas fir [Pseudotsuga menziesii var. menziesii (Mirb.) Franco] using an individual-tree growth and yield model TASS (Tree and Stand Simulator). The simulations were based on seed set, nursery culling rates, and 10-year-old field test performance for trees resulting from crosses between unrelated individuals and for inbred trees produced through mating between half-sibs, full-sibs, parents and offspring and self-pollination. Results indicate that inclusion of a small proportion of related clones in seed orchards will have relatively low impacts on stand yields due to low probability of related individuals mating, lower probability of producing acceptable seedlings from related matings than from unrelated matings, and a greater probability of competition-induced mortality for slower growing inbred individuals than for outcrossed trees. Thus, competition reduces the losses expected due to inbreeding depression at harvest, particularly on better sites with higher planting densities and longer rotations. Slightly higher breeding values for related clones than unrelated clones would offset or exceed the effects of inbreeding resulting from related matings. Concerns regarding the maintenance of genetic diversity are more likely to limit inclusion of related clones in orchards than inbreeding depression for final stand yield.


Genetic Gain Site Index Seed Orchard Related Clone Reproductive Phenology 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This project was funded by the Operational Tree Improvement Program (OTIP) under the Forest Genetics Council of British Columbia, Canada and the Natural Sciences and Engineering Research Council of Canada (NSERC) Industry Research Chair in Genetics (SNA). We thank Dr. Ken Mitchell for his helpful advice on using TASS to conduct this study.


  1. Di Lucca CM (1999) TASS/SYLVER/TIPSY: systems for predicting the impact of silvicultural practices on yield, lumber value, economic return and other benefits. In: Bamsey CR (ed) Stand density management conference: using the planning tools. Clear Lake Ltd, Edmonton, 23–24 November 1998, pp 7–16Google Scholar
  2. Durel CE, Bertin P, Kremer A (1996) Relationship between inbreeding depression and inbreeding coefficient in maritime pine (Pinus pinaster). Theor Appl Genet 92:347–356CrossRefGoogle Scholar
  3. El-Kassaby YA, Davidson R (1991) Impact of pollination environment manipulation on the apparent outcrossing rate in a Douglas fir seed orchard. Heredity 66:55–59Google Scholar
  4. El-Kassaby YA, Parkinson J, Devitt WJB (1986) The effect of crown segment on the mating system in a Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) seed orchard. Silvae Genet 35:149–155Google Scholar
  5. Erickson VJ, Adams WT (1989) Mating success in a coastal Douglas fir seed orchard as affected by distance and floral phenology. Can J For Res 19:1248–1255Google Scholar
  6. Eriksson G, Namkoong G, Roberds JH (1993) Dynamic gene conservation for uncertain futures. For Ecol Manage 62:15–37CrossRefGoogle Scholar
  7. Griffin AR, Lindgren D (1985) Effect of inbreeding on production of filled seed in Pinus radiata - experimental results and a model of gene action. Theor Appl Genet 71:334–343Google Scholar
  8. Libby WJ, Cockerham CC (1980) Random non-contiguous plots in interlocking field layouts. Silvae Genet 29:183–190Google Scholar
  9. Lowe WJ, van Buijtenen JP (1986) The development of a sublining system in an operational tree improvement program. In: Proceedings of IUFRO conference on breeding theory, progeny testing and seed orchards, Williamsburg,1986Google Scholar
  10. McKeand SE, Bridgwater FE (1998) A strategy for the third breeding cycle of loblolly pine in the southeastern US. Silvae Genet 47:223–234Google Scholar
  11. Mitchell KJ (1975) Dynamics and simulated yield of Douglas fir. For Sci Monogr 17:39Google Scholar
  12. Namkoong G 1989. Population genetics and the dynamics of conservation. In: Knutson LS (ed) Biotic diversity and germplasm preservation, global imperatives. Kluwer, Dordrecht, pp 161–181Google Scholar
  13. Namkoong G, Barnes RD, Burley J (1980) A philosophy of breeding strategy for tropical forest trees. Trop For Pap 16, Oxford University, OxfordGoogle Scholar
  14. Neale DB, Adams WT (1985) The mating system in natural and shelterwood stands of Douglas fir. Theor Appl Genet 71:201–207Google Scholar
  15. Orr-Ewing AL (1976) Inbreeding Douglas fir to the S3 generation. Silvae Genet 25:179Google Scholar
  16. Plessas ME, Strauss SH (1986) Allozyme differentiation among populations, stands, and cohorts in Monterey pine. Can J For Res 16:1155–1164Google Scholar
  17. Prat D, Burczyk J (1998) Genetic variation and mating system in a native provenance and the derived seed orchard of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco). For Genet 5:201–209Google Scholar
  18. Prat D, Caquelard T (1995) Mating system in a clonal Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) seed orchard I. Gene diversity and structure. Ann Sci For 52:201–211Google Scholar
  19. SAS Institute Inc. (1989) SAS/STAT(R) User’s guide v6, 4th edn. Cary, N.C.Google Scholar
  20. Show DV, Allard RW (1982) Estimation of outcrossing rate in Douglas fir using isozyme markers. Theor Appl Genet 62:113–120Google Scholar
  21. Sniezko RA, Zobel BJ (1988) Seedling height and diameter variation of various degrees of inbred and outcross progenies of loblolly pine. Silvae Genet 37:50–60Google Scholar
  22. Sorenson FC (1971) Estimate of self-fertility in coastal Douglas fir from inbreeding studies. [Pseudotsuga menziesii]. Silvae Genet 20:115–120Google Scholar
  23. Sorensen FC (1997) Effects of sib mating and wind pollination on nursery seedling size, growth components, and phenology of Douglas fir seed orchard progenies. Can J For Res 27:557–566CrossRefGoogle Scholar
  24. Sorensen FC (1999) Relationship between self-fertility, allocation of growth, and inbreeding depression in three coniferous species. Evolution 53:417–425Google Scholar
  25. Sorensen FC, Cress DW (1994) Effects of sib mating on cone and seed traits in coastal Douglas fir. Silvae Genet 43:338–345Google Scholar
  26. Sorensen F, Miles R (1982) Inbreeding depression in height, height growth, and survival of Douglas fir, ponderosa pine, and noble fir to 10 years of age. For Sci 28:283–292Google Scholar
  27. Stoehr MU, Orvar BL, Gawley TMV Jr, Webber JE, Newton CH (1998) Application of a chloroplast DNA marker in seed orchard management evaluations of Douglas fir. Can J For Res 28:187–195CrossRefGoogle Scholar
  28. Takaso T, Owens JN (1994) Effects of ovular secretions on pollen in Pseudotsuga-menziesii (Pinaceae). Am J Bot 81:504–513Google Scholar
  29. Vanclay JK (1991) Seed orchard designs by computer. Silvae Genet 40:89–91Google Scholar
  30. Williams C, Savolainen O (1996) Inbreeding depression in conifers: implications for breeding strategy. For Sci 42:102–117Google Scholar
  31. Woods JH, Heaman JC (1989) Effect of different inbreeding levels on filled seed production in Douglas fir. Can J For Res 19:54–59Google Scholar
  32. Woods JH, Wang T, Aitken SN (2002) Effects of inbreeding on coastal Douglas fir: nursery performance. Silvae Genet 51:163–170Google Scholar

Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • Tongli Wang
    • 1
    Email author
  • Sally N. Aitken
    • 1
  • Jack H. Woods
    • 2
  • Ken Polsson
    • 3
  • Steen Magnussen
    • 4
  1. 1.Department of Forest SciencesUniversity of British ColumbiaVancouverCanada
  2. 2.SelectSeed Company Ltd.DuncanCanada
  3. 3.Research BranchBritish Columbia Ministry of ForestsVictoriaCanada
  4. 4.Canadian Forestry Service Pacific Forestry CentreVictoriaCanada

Personalised recommendations