Overview

Maize (Zea mays L.), or corn, is the most important cereal crop in sub-Saharan Africa and, with rice and wheat, one of the three most important cereal crops in the world. Maize is high yielding, easy to process, readily digested, and cheaper than other cereals. It is also a versatile crop; growing across a range of agroecological zones. Every part of the maize plant has economic value: the grain, leaves, stalk, tassel, and cob can all be used to produce a large variety of food and non-food products.

In industrialized countries, maize is largely used as livestock feed and as a raw material for industrial products, while in developing countries, it is mainly used for human consumption. In sub-Saharan Africa, maize is a staple food for an estimated 50% of the population. It is an important source of carbohydrate, protein, iron, vitamin B, and minerals. Africans consume maize as a starchy base in a wide variety of porridges, pastes, grits, and beer. Green maize (fresh on the cob) is eaten parched, baked, roasted or boiled; playing an important role in filling the hunger gap after the dry season.

Statistics

According to FAO data, the area planted to maize in West and Central Africa alone increased from 3.2 million in 1961 to 8.9 million in 2005. This phenomenal expansion of the land area devoted to maize resulted in increased production from 2.4 million metric tonnes in 1961 to 10.6 million metric tonnes in 2005. While the average yield of maize in developed countries can reach up to 8.6 tonnes per hectare, production per hectare is still very low (1.3 tonnes per hectare).

How maize is grown

Throughout the tropics and subtropics, small-scale farmers grow maize, mostly for subsistence as part of agricultural systems that feature several crops and sometimes livestock production. Unlike in the developed countries where hybrid maize varieties are commonly grown with high inputs using mechanized operations, the production systems in sub-Saharan Africa often lack inputs such as fertilizer, improved seed, irrigation, and labor.

Constraints to maize production

An array of diseases plagues Maize growing areas in sub-Saharan Africa. These include downy mildew, rust, leaf blight, stalk and ear rots, leaf spot, and maize streak virus. Insect pests, including stem and ear borers, armyworms, cutworms, grain moths, beetles, weevils, grain borers, rootworms, and whitegrubs are also a great threat to the survival of maize in Africa. In the Nigerian savanna, for example, weed-related yield losses ranging from 65 to 92% have been recorded. The parasitic weed, known as witchweed (Striga), is a major pest in sub-Saharan Africa and causes estimated cereal grain losses of up to US$7 billion. This adversely affects the lives of about 300 million people.

The limited use of nitrogenous fertilizers and the declining soil fertility are problems for maize production in sub-Saharan Africa. Also, periodic drought caused by irregular rainfall distribution reduces maize yields by an average of 15% each year. This is equivalent to at least US$200 million in foregone grain. The effects of prolonged droughts, such as those that have struck Eastern and Southern Africa in recent years, have been disastrous.

Our work on maize

Our scientists have made early efforts on the development of high yielding open-pollinated varieties of maize with resistance to the prevailing major diseases in the humid forest and moist savanna. The wide spread outbreak of the maize streak virus (MSV) disease in the 1970s and the research accomplishments of our scientists to combat the disease contributed to our merit of the King Baudouin award in 1986. Over the past 20 years, we have supplied the national maize research programs with streak-resistant maize germplasm and screening methodology for incorporating resistance into elite adapted materials. Direct utilization of broad-based germplasm with resistance to streak, blight, rust, and leaf spot has been recorded in several lowland areas of Africa. Furthermore, working with the national program in Nigeria, several downy mildew resistant varieties have been released in the last few years.

Our effort has contributed to a significant expansion in maize production in many countries in West and Central Africa, notably Bénin, Burkina Faso, Cameroon, Gambia, Ghana, Mali, Senegal, and Togo. This was made possible because farmers adopted early-maturing improved varieties identified from regional trials which we coordinated, in collaboration with SAFGRAD, as well as the availability of intermediate and late maturing improved maize varieties from us. The new varieties yield up to twice as much as traditional varieties and some varieties are ready for harvest in less than 3 months. The development of extra-early maize varieties enabled maize production to expand into new areas, especially to the Sudan savannas where the short rainy season had adversely affected maize cultivation in the past. An impact study estimated that gains in maize production are sufficient to feed 40 million people annually. This increase represents a minimum of US$1.2 billion a year.

Our work on breeding maize for N-use efficiency resulted in the development of maize varieties, which are being widely tested on-farm in Nigeria and other countries in West Africa. Combating Striga has also been one of our focal research areas since the mid-1980s. We have achieved a remarkable success in breeding extra-early, early-, intermediate-, and late-maturing maize varieties that can tolerate Striga and also suppress its growth. We have developed maize varieties with resistance to pink and sugarcane stem borers and have deployed them to stem-borer endemic areas of Nigeria and Cameroon.

Our postharvest researchers have been developing effective and simple machines and tools that reduce the traditional processing time and labor as well as production losses. In the area of maize utilization, we have trained about 500 people and our scientists have developed a range of new products.

Recently, we engaged in research aimed at enhancing the lysine and tryptohan as well as micronutrient content of maize to combat the widespread diseases caused by macro and micronutrient deficiencies. We are also developing maize varieties with resistance to mycotoxin production in collaboration with advanced laboratories to minimize the health hazards of these toxins on humans.

In West and Central Africa, we have been contributing significantly to the capacity building of the national maize research systems. From 1970 to 1998 we have trained a total of 490 scientists in maize-related research.

Our partners

We are in collaboration with the West and Central Collaborative Maize Research Network (WECAMAN), which is involved in strengthening the capacity of NARS by distributing improved germplasm to its participating countries and providing grants for promoting the adoption of improved maize varieties through extensive on-farm testing community-based seed production schemes for farmers. Our institute also provides parental lines of hybrids to small and medium seed companies, free of charge, to accelerate their efforts at making quality seeds accessible to farmers. Seed companies in Nigeria officially announced open-pollinated maize varieties and hybrids developed at our institute in their seed catalogs

IITA and CIMMYT have had collaborative projects in a number of fronts in Africa. A number of projected focusing on major production constraints have been jointly implemented by the two centers. Furthermore, we collaborate with universities and advanced institutions to employ cutting-edge science for developing products that offer better resistance to biological and environmental stresses as well as improved nutrition. The alliances with universities and advanced institutions have been created based on compatibility of activities and comparative advantages.