Peer review

Experiments were conducted for two seasons on eight farmers' fields in Omay and Siabuwa (semi-arid Natural Region V) smallholder (communal) areas of Zimbabwe to determine the grain yield and economic performance of ten experimental open-pollinated varieties (OPV) and five released hybrids of maize (that farmers currently use), grown without fertilizer and with 75kg N, 15kg P and 14kg K/ha. Grain yields for the hybrids, as a group, were consistently larger than those for the five hightest yielding OPV at all sites by an average of 165 kg/ha (19%) without fertlizer and 290kg/ha (16%) with fertilizer. However, three OPV, most consistently ([EVPOP 30-SRBC2/NPPxSC] C1F2, came within five per cent of the hybrid yields at one or both levels of fertilizer. Without fertilizer (current farmer practice), smaller yield differences between OPV and hybrids were seen at low yield sites (those with a mean grain yield below 1.3 t/ha). Omay and Siabuwa are geographically isolated, farmers are cash constrained, and maize seed and fertilizer are expensive and sometimes unavailable. Under these circumstances and despite the grain yield superiority of the hybrids, we calculate it should be more economical for farmers to plant new OPV seed every fourth year and replant saved OPV seed in other years rather than plant new F1 hybrid seed each year. But OPV seed would have to be made available to farmers and farmers trained in seed selection and storage. However, at Harare seed prices it was highly economical to plant hybrid seed and a simpler stratey would be to improve the marketing of hybrid maize seed in the area. Although most farmers in Omay and Siabuwa do not apply fertilizer to maize, economic analysis showed that 75 kg N, 15 kg P and 14 kg K/ha fertilizer is profitable at present for hybrid maize (and for OPV) in the area in years with slightly below average rainfall.

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