Leveraging from genotype by environment interaction for bread wheat production in eastern Africa
Developing high yielding and stable genotypes for wide and specific adaptation is important in wheat (Triticum aestivum L.) production. The objective of this study was to exploit the gains from genotype by environment interaction for increased bread wheat production in eastern Africa. Thirty-three advanced bread wheat lines, along with two check varieties (Danda’a and Hidasse) were evaluated at ten locations in Ethiopia and Kenya. The experiment was laid out in alpha lattice design in three replications. The analysis of variance for AMMI model of grain yield showed that environment, genotypes and genotype by environment interaction (GEI) effects were highly significant (P<0.01), and accounted for 62.4, 4.8 and 15.8% of the total sum of squares variations, respectively. High environmental and significant GEI indicated that the environment had major influence for inconsistent performance. Grain yield of the genotypes ranged from 1.58 t ha-1 (G30) to 9.05 t ha-1 (G31). Genotypes G31, G18 and G35 were the best performing lines across environments. The AMMI biplot, using the first two principal components, showed that testing sites Njoro and Arsi-Robe highly discriminated the tested genotypes. Njoro was negatively interacting with high yielding genotypes, and was a different environment from any of the testing locations of Ethiopia for these sets of genotypes. It may be difficult to develop high yielding and stable varieties for the two countries, but one should look for specific adaptation. Genotypes G31 and G18 produced high grain yield, with low stability across locations which were favouring high yielding environments. However, G21 and G8 had above mean grain yield and good stability across locations. Therefore, wheat breeding for specific adaptability is very important to exploit the genetic advantage of specific genotypic performances across the region. However, extensive testing considering many locations across East African countries is vital for delineating and exploiting wheat environments for marked developments.
Key Words: AMMI, GEI, Triticum aestivum