Advertisement

Theoretical and Applied Genetics

, Volume 109, Issue 6, pp 1196–1203 | Cite as

Open-nucleus breeding strategies compared with population-wide positive assortative mating

I. Equal distribution of testing effort
  • M. Lstibůrek
  • T. J. MullinEmail author
  • D. Lindgren
  • O. Rosvall
Original Paper

Abstract

Positive assortative mating (PAM) can enhance the additive genetic variance in a breeding population (BP). This increases the potential for gains in the production population (PP, selected subset of the BP) for recurrent selection programs in forest trees. The assortment of mates can be either: (1) by individual tree rank across the whole BP (PAM), or (2) trees of similar rank can be merged into larger hierarchical groups and then mated randomly within group (“open”-nucleus breeding, NB). The objective of this study was to compare PAM and NB in quantitative terms. The NB simulation model assumed two tiers (nucleus, main) with unrestricted migration between the tiers. Clonal tests were used to predict breeding values and test resources per mate were kept constant for all mates. Both gain and diversity were combined into a single selection criterion, “group-merit selection.” Alternatives were compared over five breeding cycles by considering genetic gain and diversity in a selected PP established in a seed orchard. The assortment of mates in both alternatives enhanced additive variance and increased the additive effect in the BP, leading to additional gain in the PP. Gains generated under PAM always exceeded gains under NB. Thus, the main message from this study is that PAM in both the short- and long-term results in more gain at any target level of diversity in the PP (the breeder’s target) than is achieved by the NB alternative. The optimum size of the nucleus varies with the desired level of seed orchard diversity. At lower target diversity, smaller nucleus sizes are favorable, while larger sizes result in more gain when seed orchard diversity is considered more important.

Keywords

Random Mating Breeding Population Genetic Gain Assortative Mating Seed Orchard 
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.

Notes

Acknowledgements

We gratefully acknowledge financial support from the Föreningen Skogsträdsförädling (Swedish Tree Breeding Association) and the North Carolina State University–Industry Cooperative Tree Improvement Program. We also thank Dr. Jennifer Myszewski and Dr. Floyd Bridgwater for their valuable comments on the manuscript and Dr. Ross Shepherd for his generous help with the animal breeding terminology.

References

  1. Andersson EW (1999) Gain and diversity in multi-generation breeding programs. PhD thesis, Swedish University of Agricultural Sciences, UmeåGoogle Scholar
  2. Baker RJ (1973) Assortative mating and artificial selection. Heredity 31:231–238PubMedGoogle Scholar
  3. Baker RJ (1986) Selection indices in plant breeding. CRC Press, Boca RatonGoogle Scholar
  4. Breese EL (1956) The genetical consequences of assortative mating. Heredity 10:323–343Google Scholar
  5. Bulmer MG (1971) The effect of selection on genetic variability. Am Nat 105:201–211CrossRefGoogle Scholar
  6. Cockerham CC (1967) Group inbreeding and coancestry. Genetics 56:89–104PubMedGoogle Scholar
  7. Cotterill PP (1989) The nucleus breeding system. Proc South For Tree Improv Conf 20:36–42Google Scholar
  8. Cotterill PP, Dean CA, Cameron J, Brindbergs M (1989) Nucleus breeding: a new strategy for rapid improvement under clonal forestry. In: Gibson GL, Griffin AR, Matheson AC (eds) Breeding tropical trees: population structure and genetic improvement strategies in clonal and seedling forestry. (Proceedings of a conference held in Pattaya, Thailand, 28 November–3 December 1988) Winrock International, Arlington, pp 39–51Google Scholar
  9. Crow JF (1986) Basic concepts in population, quantitative, and evolutionary genetics. Freeman, New YorkGoogle Scholar
  10. Crow JF, Felsenstein J (1968) The effects of assortative mating on the genetic composition of a population. Eugen Q 15:85–97PubMedGoogle Scholar
  11. Crow JF, Kimura M (1970) An introduction to population genetics theory. Harper and Row, New YorkGoogle Scholar
  12. Danusevicius D, Lindgren D (2002) Efficiency of selection based on phenotype, clone and progeny testing in long-term breeding. Silvae Genet 51:19–26Google Scholar
  13. del-Bosque González AS (1989) Simulations of nucleus breeding schemes for wool production. PhD thesis, University of New England, ArmidaleGoogle Scholar
  14. Falconer DS, Mackay TFC (1996) Introduction to quantitative genetics, 4th edn. Longman, HarlowGoogle Scholar
  15. Hagedorn SF (1991) Breeding Pinus patula for plantation establishment in the Natal midlands. (Annual research report 1991) Institute for Commercial Forestry Research, Pietermaritzburg, pp 204–207Google Scholar
  16. Hopkins IR, James JW (1978) Theory of nucleus breeding schemes with overlapping generations. Theor Appl Genet 53:17–24Google Scholar
  17. Isik F, Li B, Frampton J, Goldfarb B (2003) Efficiency of seedlings and rooted cuttings for testing and selection in Pinus taeda. For Sci 50:44–53Google Scholar
  18. James JW (1977) Open nucleus breeding systems. Anim Prod 24:287–305Google Scholar
  19. James JW (1978) Effective population size in open nucleus breeding schemes. Acta Agric Scand 28:387–392Google Scholar
  20. Jorjani H (1995) Genetic studies of assortative mating in selected and unselected populations. PhD thesis, Swedish University of Agricultural Sciences, UppsalaGoogle Scholar
  21. Karlsson B, Rosvall O (1993) Breeding programmes in Sweden 3. Norway spruce. In: Lee SJ (ed) Progeny testing and breeding strategies. (Proceedings of the Nordic group of tree breeding, October 1993, Edinburgh) Forestry Commission, Edinburgh, pp 135–141Google Scholar
  22. King JN, Johnson GR (1993) Monte Carlo simulation models of breeding-population advancement. Silvae Genet 42:68–78Google Scholar
  23. Kinghorn B, Werf J, Ryan M (2000) Animal breeding: use of new technologies: a textbook for consultants, farmers, teachers and for students of animal breeding. University of Sydney, SydneyGoogle Scholar
  24. Lange AO, De Lange AC (1974) A simulation study of the effects of assortative mating on the response to selection. In: Garsi (ed) First world congress on genetics applied to livestock production, 7–11 October 1974. 3. Contributed papers. Madrid, pp 421–425Google Scholar
  25. Lindgren D, Mullin TJ (1997) Balancing gain and relatedness in selection. Silvae Genet 46:124–129Google Scholar
  26. Lindgren D, Gea LD, Jefferson PA (1996) Loss of genetic diversity monitored by status number. Silvae Genet 45:52–59Google Scholar
  27. Lstibůrek M, Mullin TJ, Lindgren D, Rosvall O (2004) Open-nucleus breeding strategies compared with population-wide positive assortative mating. II. Unequal distribution of testing effort. Theor Appl Genet. DOI 10.1007/s00122-004-1737-2Google Scholar
  28. Lynch M, Walsh B (1998) Genetics and analysis of quantitative traits. Sinauer, Sunderland, Mass.Google Scholar
  29. Mahalovich MF, Bridgwater FE (1989) Modeling elite populations and positive assortative mating in recurrent selection programs for general combining ability. Proc South For Tree Improv Conf 20:43–49Google Scholar
  30. 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
  31. Mikola J (2002) Long-term tree breeding strategy in Finland: integration of seed production and breeding. In: Haapanen M, Mikola J (eds) Integrating tree breeding and forestry. (Proceedings of the Nordic group for management of genetic resources of trees, Mekrijärvi, March 2001. Research papers 842) Finnish Forest Research Institute, Mekrijärvi, pp 12–13Google Scholar
  32. Mueller JP, James JW (1983) Effects of reduced variance due to selection in open nucleus breeding systems. Aust J Agric Res 34:53–62Google Scholar
  33. Mullin TJ, Park YS (1995) Stochastic simulation of population management strategies for tree breeding: a new decision-support tool for personal computers. Silvae Genet 44:132–141Google Scholar
  34. Roden JA (1994) Review of the theory of open nucleus breeding systems. Anim Breed Abstr 62:151–157Google Scholar
  35. Roden JA (1995) A simulation study of open nucleus and closed nucleus breeding systems in a sheep population. Anim Sci 60:117–124Google Scholar
  36. Rosvall O (1999) Enhancing gain from long-term forest tree breeding while conserving genetic diversity. PhD thesis, Swedish University of Agricultural Sciences, UmeåGoogle Scholar
  37. Rosvall O, Mullin TJ (2003) Positive assortative mating with selection restrictions on group coancestry enhances gain while conserving genetic diversity in long-term forest tree breeding. Theor Appl Genet 107:629–642CrossRefPubMedGoogle Scholar
  38. Rosvall O, Lindgren D, Mullin TJ (1999) Sustainability robustness and efficiency of a multi-generation breeding strategy based on within-family clonal selection. Silvae Genet 47:307–321Google Scholar
  39. Rosvall O, Mullin TJ, Lindgren D (2003) Controlling parent contributions during positive assortative mating and selection increases gain in long-term forest tree breeding. For Genet 10:35–53Google Scholar
  40. Shepherd RK (1991) Multi-tier open nucleus breeding systems. PhD thesis, University of New England, ArmidaleGoogle Scholar
  41. Shepherd RK, Kinghorn BP (1992) Optimising multi-tier open nucleus breeding schemes. Theor Appl Genet 85:372–378Google Scholar
  42. Wellendorf H, Skov E, Kjaer E (1994) Suggested updating of improvement strategy for Danish-grown Norway spruce, vol 25. Forest Tree Improvement, Arboretet Horsholm, pp 1–12Google Scholar
  43. White TL, Hodge GR, Powell GL (1993) An advanced-generation tree improvement plan for slash pine in the Southeastern United States. Silvae Genet 42:359–371Google Scholar
  44. White TL, Matheson AC, Cotterill PP, Johnson GR, Rout AF, Boomsma DB (1999) A nucleus breeding plan for radiata pine in Australia. Silvae Genet 48:122–133Google Scholar
  45. Williams CG, Savolainen O (1996) Inbreeding depression in conifers: implications for breeding strategy. For Sci 42:102–117Google Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • M. Lstibůrek
    • 1
  • T. J. Mullin
    • 1
    Email author
  • D. Lindgren
    • 2
  • O. Rosvall
    • 3
  1. 1.Department of ForestryNorth Carolina State UniversityRaleighUSA
  2. 2.Department of Forest Genetics and Plant PhysiologySwedish University of Agricultural SciencesUmeåSweden
  3. 3.The Forestry Research Institute of Sweden (SkogForsk)SävarSweden

Personalised recommendations