Developing and deploying insect resistant maize varieties to reduce pre- and post-harvest food losses in Africa

Maize grain yield in Africa is low, 1.5 t ha(-1) compared to the global average of 4.9 t ha(-1). Maize production in Africa is constrained by various abiotic (drought, soil fertility) and biotic factors (insect pests, weeds and diseases). Stem borers and postharvest insect pests play considerable roles in reducing maize yield through damaging the leaves, stems, ears, and kernels. Stem borers can cause 10-15 % yield losses while the postharvest insect pests, particularly, the larger grain borer and maize weevil, can cause 14-36 % grain losses. The use of chemical insecticides has been recommended; however, in addition to health concerns, insecticides are expensive and not accessible to smallholders. Developing high yielding insect resistant maize varieties could do much to minimize the losses. Resistance of maize to stem borers and post-harvest insect pests are genetic traits which manifests themselves in resistant varieties. Resistance is available to farmers encapsulated in the seed, which ensures that after purchasing the seed, farmers need not invest in any further inputs to control stem borers and post-harvest pests. CIMMYT and its partners have developed through conventional breeding and have deployed several hybrids and open-pollinated varieties, which are insect resistant and high yielding. Sources of maize germplasm resistant to stem borers and postharvest insect pests, and performance of the new insect resistant and high yielding maize hybrids are reviewed and discussed.