Diverse Production Environments Research Articles

Past and potential impacts of maize research in sub-Saharan Africa: a critical assessment

Over the past twenty years, research progress in maize, the single most important food staple in sub-Saharan Africa, has been comparable to progress in other primarily smallholder maize systems in the developing world. Both the number of varietal releases per million hectares of maize and the adoption of improved maize varieties and hybrids are similar to the rates achieved in other regions. This has occurred despite fewer maize breeders per million tons of maize, greater reliance on the public sector, and somewhat more diverse production environments in sub-Saharan Africa. Nonetheless, adoption of improved maize materials has remained patchy, constrained in some cases by failure to incorporate smallholder preferences adequately, and in others by insufficient supporting infrastructure, particularly in development of seed systems. Furthermore, despite an apparently greater investment in crop management research in the region relative to other developing areas, appropriate technology for maintenance of soil fertility in the face of increasing population pressure requires much more attention. This technology will require a combination of both external and internal sources of nutrients. Crop management technology must also be evaluated in terms of effects on seasonal labor demand. Because of the relative diversity in African environments and infrastructural constraints, high-payoff maize technology in sub-Saharan Africa will require particularly careful attention to areas outside maize research itself—policy design, institution building, and human capital development.

Population Stability of ‘Latar’ Orchardgrass as Affected by Six Diverse Seed Production Environments1

Six plant characteristics of ‘Latar’ orchardgrass (Dactylis glomerata L.) were studied at Prosser, Wash., to evaluate population stability after two generations of increase at four locations in the western USA and at two locations in Japan. Populations consisting of 108 spaced plants from each of 35 increases were compared to plants from the original seed lot used at the six locations to establish the initial seed increases. The two increases made at Sapporo, Japan, did not differ from the original seed, but the six increases made at Shafter, Calif., had less spring vigor, earlier date of heading, earlier date of anthesis, fewer number of heads, shorter plant height, and less stem angle. The six increases each made at Tehachapi, California, and Aurora, Ore., differed only in stem angle. The five increases made at Nishinasuno, Japan, and the 10 increases made at Prosser differed in three plant characteristics. First‐generation seed increases tended to produce plants that were shorter, more erect, and less vigorous, with fewer heads and earlier heading and anthesis dates than plants from the original seed. Second‐generation increases continued this trend and were significantly different from the original seed in five of six characters studied.