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Genotype by environment interactions (GxE) - Van Etten

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Presentation by Jacob van Etten.

CCAFS workshop titled "Using Climate Scenarios and Analogues for Designing Adaptation Strategies in Agriculture," 19-23 September in Kathmandu, Nepal.

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Genotype by environment interactions (GxE) - Van Etten

  1. 1. Genotype by environment interactions (GxE) and climate change<br />Jacob van Etten<br />
  2. 2. G x E<br />P = G + E + G*E<br />P = Production<br />G = Genotype<br />E = Environment<br />
  3. 3. In other words...<br />Suppose we have<br /><ul><li> a continuous environmental variable
  4. 4. two different genotypes i = {1,2}</li></ul>Now the regression equation becomes:<br />P = (β0 +) β1Gi + β2E + β3GiE (+ e)<br />
  5. 5. Purely genetic difference<br />P = β1Gi + β2E + β3GiE<br />β1≠ 0<br />β2 = 0<br />β3 = 0<br />
  6. 6. Purely additive interaction<br />P = β1Gi + β2E + β3GiE<br />β1≠ 0<br />β2≠ 0<br />β3 = 0<br />
  7. 7. Non-additive interaction<br />P = β1Gi + β2E + β3GiE<br />β1 ≠ 0<br />β2 ≠ 0<br />β3 ≠ 0<br />
  8. 8. Cross-over: When does another variety take over?<br />climate change -><br />
  9. 9. Lobell et al. (2011) study<br />Weather variables<br />Yield<br />Ecophysiological variables<br />Weather variables<br />Yield<br />Ecophysiological variables<br />Estimate statistical model<br />Calculate<br />+ 1 °C<br />Predict using estimated model<br />Recalculate<br />
  10. 10. Lobell et al. (2011)<br />
  11. 11. Climate change impact maps<br />
  12. 12. GxE: OPV vs hybrid<br />
  13. 13. GxE: duration<br />
  14. 14. What breeders usually do: AMMI<br />Additive Main Effects and Multiplicative Interaction<br />Production = G + E + residuals<br />Then do a PCA on residuals to visualize the GxE interactions.<br />(An alternative is to only remove G – known as GGE.)<br />
  15. 15. Example of AMMI Biplot<br />Stress<br />Normal<br />
  16. 16. RDA: adding environmental variables<br />
  17. 17. Variety adaptation zones<br />
  18. 18. Final remarks<br />Statistical models complement mechanistic models<br /><ul><li> Use real data for places where mechanistic models have not been calibrated
  19. 19. Get an estimate of the error
  20. 20. Link to daily plant breeding practice!</li></ul>Package weatherData to get weather data for trial locations and derive ecophysiological variables<br />

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