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Developing high yielding maize (Zea mays L.) varieties that have relatively high grain protein content under low nitrogen stress is critical to ensure food and nutrition security in sub-Saharan Africa. This study evaluated the efficiency for fertilizer N recovery, grain yield and grain protein content of 10 maize hybrids selected for their contrasting yield performance under low-N stress conditions in the field. The hybrids were grown under 6 N rates (0-10-20-40-80 and 160 kg Ammonium Nitrate ha−1) at 2 sites that differ for residual soil nitrogen (N-NO3). Fertilizer N recovery, estimated using the difference method, decreased with increasing N rates or residual soil N and was significantly higher for the low-N tolerant (LNT) hybrids than low-N sensitive (LNS) hybrids, especially at low N rates. Although there was yield increase with increased N rate, the yield of tolerant hybrids responded more strongly than that of sensitive ones. Under low residual soil N, higher grain yield was associated with lower grain protein content in both low-N tolerant and susceptible hybrids but tolerant ones exhibited a significantly lower decrease in grain protein content compared to susceptible hybrids. In addition, LNT hybrids were able to maintain relatively higher grain protein content at high yield level under depleted soil N conditions as well as under high N level. We concluded that LNT hybrids could contribute to optimizing the use of small N fertilizer rates by resource-poor smallholder farmers to increase the nutritional value and profitability of producing maize.

Maize production must increase three-fold in sub-Saharan Africa to meet the needs of future generations. Sustainably increasing maize production will require a portfolio of complementary technologies and policies. In this review we highlight four challenges to achieve this improvement. Improved nutritional density of maize in farmers’ fields and increased adoption of new varieties and faster varietal replacement. Increased fertilizer use should increase maize yields but there is increasing evidence that low and variable returns on investment can limit uptake. Finally, adoption of new technologies is not uniform, with lower rates of adoption by female farmers. Without addressing gender specific challenges to adoption, technologies will never achieve their desired impacts. Given the scope of the challenge, strategies to improve maize productivity must overcome these constraints as part of an integrative approach.

Maize is a major staple food crop in southern Africa and stress tolerant improved varieties have the potential to increase productivity, enhance livelihoods and reduce food insecurity. This study uses big data in refining the geospatial targeting of new drought-tolerant (DT) maize varieties in Malawi, Mozambique, Zambia, and Zimbabwe. Results indicate that more than 1.0 million hectares (Mha) of maize in the study countries is exposed to a seasonal drought frequency exceeding 20% while an additional 1.6 Mha experience a drought occurrence of 10–20%. Spatial modeling indicates that new DT varieties could give a yield advantage of 5–40% over the commercial check variety across drought environments while crop management and input costs are kept equal. Results indicate a huge potential for DT maize seed production and marketing in the study countries. The study demonstrates how big data and analytical tools enhance the targeting and uptake of new agricultural technologies for boosting rural livelihoods, agribusiness development and food security in developing countries., The IFAMR is published quarterly my IFAMA. For more information visit: www.ifama.org.