Table 3. Analysis of factors that influence the variation in predictive ability of single and multi-environment prediction models.
The effects of the statistical model (GBLUP, RKHS-1 and RKHS-2), the trait (DTF, GY and PH), the cross-validation strategy (CV1 and CV2), drought stress environments (E1, E2 and E3) and different combinations of training environment and their interactions were evaluated.
| Analysis with only main effects | |||||
| Source | DF | SS | MS | F-value | ProbF |
| Model | 10 | 309.728 | 30.973 | 1 773.667 | < 0.0001 |
| Error | 32 389 | 565.595 | 0.017 | ||
| Corrected Total | 32 399 | 875.323 | |||
| Trait | 2 | 145.581 | 72.791 | 7 141.750 | < .0001 |
| Model | 1 | 10.730 | 10.730 | 1 052.770 | < .0001 |
| Method | 2 | 1.426 | 0.713 | 69.930 | < .0001 |
| CV | 1 | 15.993 | 15.993 | 1 569.160 | < .0001 |
| Drought environment | 2 | 134.409 | 67.204 | 6 593.650 | < .0001 |
| Training environment | 2 | 1.588 | 0.794 | 77.880 | < .0001 |
| Analysis with main effects and all first-order interactions | |||||
| Model | 51 | 496.946 | 9.744 | 833.032 | < 0.0001 |
| Error | 32 348 | 378.377 | 0.012 | ||
| Corrected Total | 32 399 | 875.323 | |||
| Trait | 2 | 145.581 | 72.791 | 7 141.750 | < .0001 |
| Model | 1 | 10.730 | 10.730 | 1 052.770 | < .0001 |
| Method | 2 | 1.426 | 0.713 | 69.930 | < .0001 |
| CV | 1 | 15.993 | 15.993 | 1 569.160 | < .0001 |
| Drought environment | 2 | 134.409 | 67.204 | 6 593.650 | < .0001 |
| Training environment | 2 | 1.588 | 0.794 | 77.880 | < .0001 |
| Trait × Model | 2 | 4.605 | 2.303 | 225.920 | < .0001 |
| Trait × Method | 4 | 1.418 | 0.355 | 34.780 | < .0001 |
| Model × Method | 2 | 1.812 | 0.906 | 88.910 | < .0001 |
| Trait × CV | 2 | 1.882 | 0.941 | 92.330 | < .0001 |
| Model × CV | 1 | 15.993 | 15.993 | 1 569.160 | < .0001 |
| Method × CV | 2 | 1.627 | 0.814 | 79.820 | < .0001 |
| Trait × Drought | 4 | 152.543 | 38.136 | 3 741.620 | < .0001 |
| Model × Drought | 2 | 0.786 | 0.393 | 38.580 | < .0001 |
| Method × Drought | 4 | 0.499 | 0.125 | 12.240 | < .0001 |
| CV × Drought | 2 | 0.792 | 0.396 | 38.840 | < .0001 |
| Trait × Training environment | 4 | 0.957 | 0.239 | 23.470 | < .0001 |
| Model × Training environment | 2 | 1.588 | 0.794 | 77.880 | < .0001 |
| Method × Training environment | 4 | 0.935 | 0.234 | 22.930 | < .0001 |
| CV × Training environment | 2 | 1.782 | 0.891 | 87.440 | < .0001 |
| Drought × Training environment | 4 | 1.686 | 0.422 | 41.350 | < .0001 |
DF: Degree of freedom; SS: Sum of squares; MS: Mean square; ×: interaction between the factors.