Table 3.
Estimates of genetic gain in grain yield within tropical maize in advanced (Stage 4) breeding pipelines of CIMMYT and IITA in Sub-Saharan Africa.
| Genetic gain (kg ha−1 year−1) | ||||||
|---|---|---|---|---|---|---|
| Breeding program | Optimum | Managed drought stress | Random/multiple stresses | Time period | Methodology | References |
| West and Central Africa | ||||||
| OPVs, early maturity |
30 (1.2) |
14 (1.1) |
40 (1.6) | 1988–2010 | Era study | Badu-Apraku et al. (2014) |
| OPVs, extra-early maturity |
67 (2.3) |
34 (3.3) |
44 (2.7) | 1988–2010 | Era study | Badu-Apraku et al. (2015) |
| Eastern and Southern Africa | ||||||
| Hybrids | 109.4 (1.4) | 32.5 (0.85) | 22.7 (0.85) | 2000–2010 | Era study | Masuka et al. (2017a) |
| OPVs, early maturity | 109.9 (1.76) | ns | 29.2 (1.21) | 2000–2010 | Era study | Masuka et al. (2017b) |
| OPVs, intermediate maturity | 79.1 (1.35) | ns | 42.3 (2.09) | 2000–2010 | Era study | Masuka et al. (2017b) |
| Southern Africa | ||||||
| Hybrids, early maturity | 83 (1.81) | 54 (2.12) | 54 (1.83) | 1999–2016 | Era study | |
| Hybrids, early maturity | 181 (2.2) | 138 (2.0) | 104 (1.9) | 2013–2018 | Rolling checks | |
| Hybrids, intermediate maturity | 177 (1.9) | 384 (2.5) | 124 (2.5) | 2013–2018 | Rolling checks | |
| Eastern Africa | ||||||
| Hybrids, intermediate maturity | 130.7 (1.75) | 79.3 (2.57) | 2013–2017 | Era study | ||
| Inbred lines |
39.3 (1.4) |
1996–2013 | Era study | Worku et al. (2016) | ||
*Number in brackets is the rate of genetic gain (expressed in percent).