Performance of Elite Maize Varieties Tested On-Farm Trials in Eastern and Southern Africa.

While average yields in the United States and other developed countries are around 8.5 t ha^-1, in eastern and southern Africa (ESA) average yields for small-holder farmers remain low at about 1 t ha^-1.  In 2006 CIMMYT initiated the Drought Tolerant Maize for Africa (DTMA) project targeted at improving maize for the drought prone mid-altitude regions of eastern and southern Africa. Nine  new CIMMYT maize hybrids and five new open-pollinated varieties (OPVs) were selected under optimal (well fertilized and well-watered conditions), rainfed, low soil nitrogen and managed drought stress environments. These were compared with the best commercial checks, older OPVs, and farmer-preferred varieties across 49 farmers’ fields in eight countries in ESA. Trials were unreplicated and conducted under farmer management, with farms considered blocks in a randomized complete-block design. Average trial yields ranged from 0.7 t ha^-1 to above 8 t ha^-1. Trials were divided into two categories based on average yield; high yields >=3 t ha^-1 (30 trials) and low yields < 3 t ha^-1 (19 trials). Repeatability of entry means was 0.80 and 0.62 in the high and low-yield trials, respectively, indicating that highly repeatable means can be estimated from unreplicated on-farm trials in ESA. The best new DTMA hybrids out-yielded the farmers’ own varieties by 35% and 25% under low- and high-yield conditions, respectively, while the best DT OPVs performed as well as the commercial hybrid SC513, which is one of the most popular varieties in southern Africa. The best hybrid out-yielded the most popular commercial check by 36% and 26% under high and low yield conditions, respectively. These results confirm the value of conventional maize breeding incorporating managed stress screening to increase yields in farmers’ fields in ESA.