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Genetic thinning of clonal seed orchards using linear deployment

Genetic thinning of clonal seed orchards using linear deployment. Forest Genetics and Tree Breeding in the Age of Genomics: Progress and Future November 1-5, 2004 Charleston Wednesday 1:30-5:40 PM Concurrent Session II: Advances in Reproductive Biology and Seed Orchards Moderator: Clem Lambeth

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Genetic thinning of clonal seed orchards using linear deployment

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  1. Genetic thinning of clonal seed orchards using linear deployment Forest Genetics and Tree Breeding in the Age of Genomics: Progress and FutureNovember 1-5, 2004Charleston Wednesday 1:30-5:40 PM Concurrent Session II: Advances in Reproductive Biology and Seed Orchards Moderator: Clem Lambeth 4:25-4:50 Seed orchard Thinning Using Linear Deployment of Clones Dag Lindgren, SLU, Sweden

  2. The authors Mohan VargheseDag Lindgren Finnvid Prescher

  3. Presents a genetic thinning algorithm Known: • Ramet number and breeding value for each clone Result: • Number of ramets to be rouged for each clone

  4. The algorithm combines the two desires: • High effective number of clones and • High genetic gain

  5. Linear deployment is optimal for establishment! • No other deployment combines higher gain with higher effective number

  6. At thinning ramets cannot be added, just withdrawn. The algorithm has to be modified. Linear deployment for genetic thinning

  7. The optimal line is the same for all clones Bondesson, L. and Lindgren, D. 1993. Optimal utilization of clones and genetic thinning of seed orchards. Silvae Genet. 42: 157-163.

  8. Math

  9. More math… The linear deployment thinning algorithm maximizing G at Ne is as follows: The algorithm results in an optimal combination of G, Ne and ramets remaining, but there are many optimal combinations. The specific solution is given by the choice of g0 and b. g0 and b are chosen to result in desired combination of values for G, Ne and ramets remaining. (Bondesson and Lindgren 1993). Note that linear deployment can be seen as a solution searching for a problem, and not as usual a problem asking for a solution. This presentation shows three practical applications

  10. Genetic thinning characteristics • Remaining ramets • Genetic gain (breeding value) • Effective clone number Linear deployment thinning is optimal No other deployment can increase one of these three factors without decreasing another

  11. This is first presentation of applications of the algorithm published 1993!

  12. Put into a worksheet… Input: breeding values, ramet numbers Output: Gain, effective number, remaining ramets per clone Linear Deployment at www.genfys.slu.se/staff/dagl

  13. Three objects

  14. At a suitable thinning intensity The graph is generated by trying different lines

  15. Result Lagan, linear deployment thinning Marginally higher gain, but many clones lost, effective clone number substantially reduced! Substantial improvement for both Gain and Effective number! Practical thinning resulted in almost full optimality!

  16. Genetic thinning Maglehem

  17. Thinning at Maglehem Truncation selection that preserves the effective number results in much lower gain!

  18. Thinning at Maglehem Truncation with the same number of ramets results in a little higher gain, but much fewer clones and effective number

  19. Thinning at Maglehem The optimality remains!

  20. Eucalyptus clone trial at Coimbatore A clonal test of Eucalyptus camaldulensis established at Coimbatore in south India comprising 87 clones (selected from 7 seedling seed orchards and commercially available clones). There were 15 ramets of each clone arranged in 3 tree plots with 5 replications. The test was to be converted to a clonal seed orchard based on height assessment in the trial at three years.

  21. The Eucalyptus clone trial at measurement and the ramets at planting

  22. Thinning Coimbatore

  23. At the same thinning intensity there are much higher retained number and effective number, but marginal loss in gain,

  24. At the same genetic gain there are much higher retained number and effective number, but a more intensive thinning is requiered.

  25. At the same effective number of clones there are a higher retained number and more gain, but a more intensive thinning is required.

  26. Conclusions • Linear deployment at thinning is theoretically optimal! • The loss from optimality because of practical difficulties is marginal and the added flexibility may offer advantages! • The added practical difficulty is marginal. • The increase in gain and clones retained at the same effective clone number are substantial! • It is sometimes possible to make significant increases for both gain and effective clone number with a moderate genetic thinning. These entities have earlier been seen as incompatible!

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