Empowering farmers, informing breeders: lessons from large-scale farmer-managed maize trials in Eastern Zambia

Summary

Smallholder farmers in sub-Saharan Africa grow maize under highly variable agro-ecological and socio-economic conditions, calling for breeding programmes that better address farmers’ conditions and needs. This study characterized farmers’ crop management practices and investigated genotype × environment (G × E) interaction patterns for maize yield in Eastern Zambia to guide the breeding strategy in this region. A participatory large-scale variety testing approach, comprising 980 mother and baby trials (MBTs) conducted under farmers’ own management practices, was implemented over the 2022 and 2023 seasons. Characterization of the MBT contexts revealed that adaptation to low nitrogen and delayed fertilization should be considered in the breeding strategy. In addition, delayed weedings explained a large proportion of genotype × farmer (G × F) interactions in both MT seasons, indicating that adaptation to weed pressure should deserve greater attention in breeding. These adaptation traits are particularly important for women, who provide most weeding labour and often have limited access to soil fertility resources. Non-repeatable G × F interactions across years, together with genotypic variance exceeding G × E interaction variance estimates, indicated that multi-year testing across MTs can identify superior and stable genotypes. At the same time, indications of specific adaptation to certain management conditions suggest potential for context-specific variety recommendations. This could offer a competitive advantage in Zambia’s maize seed market, where variety choice and information remain limited. Overall, decentralized farmer-managed testing underlined the importance of yield stability and generated reliable information on variety adaptation, while strengthening farmers’ capacity to make informed variety choices.