Maize is grown widely throughout the world in a range of agro-ecological environments. Well over 160million hectares of maize are planted worldwide. A greater weight of maize is produced each year than any other grain. About 50 species exist and consist of different colours, textures and grain shapes and sizes. White, yellow and red are the most common types.Worldwide production of maize is well over 800 million tons, with the largest producer, the United States, producing 42% of that.
Other top producing countries include China, Brazil, Mexico, Indonesia, India, France and Argentina. Maize is the most important cereal crop in sub-Saharan Africa (SSA), and the continent produces 6.5% of the world output. The largest African producer is Nigeria with nearly 8 million tons, followed by South Africa. Africa imports 28% of the required maize from countries outside the continent. Most maize production in Africa is rain fed. Irregular rainfall can often triggers famines in vulnerable regions of the continent.
Maize is rich in vitamins A, C and E, essentialminerals, and contains 9% protein. It is also rich in dietary fibre and carbohydrates which are a good source of energy. The crop is an important staple food for more than 1.2 billion people in SSA and Latin America and a key feed crop in Asia, and is actually Africa's most important staple food crop - feeding more than 300 million of the continent’s most vulnerable people. In industrialised countries, maize is largely used as livestock feed and as a raw material for industrial products. In the United States, for example, only 2.5% of the annual production is used for human food.
Worldwide human consumption of the crop is more than 116 million tons, with Africa consuming 30% and SSA 21%. Lesotho has the largest consumption per capita with 174 kg per year. Eastern and Southern Africa uses 85% of its production as food, while Africa as a whole uses 95%. Maize accounts for 30−50% of low-income household expenditures in Eastern and Southern Africa. A heavy reliance on maize in the diet, however, can lead to malnutrition and vitamin deficiency diseases such as night blindness and kwashiorkor.
Maize flour is a major ingredient in home cooking and in many industrialized food products. It is also a major source of cooking oil and of maize gluten. Maize starch can be hydrolyzed and enzymatically treated to produce syrups, particularly high fructose corn syrup - a sweetener. It is also fermented and distilled to produce grain alcohol. Maize is sometimes used as the starch source for beer. Starch from maize can also be made into plastics, fabrics, adhesives, and many other chemical products. The corn steep liquor, a by-product of maize wet milling process, is widely used in the biochemical industry and research as a culture medium to grow microorganisms.
Over 80% of the maize in South and South-East Asia is grown under rain-fed conditions prone to drought. Building on substantial breeding progress made for drought tolerance in maize in Central America and eastern & southern Africa, marker-assisted breeding can be employed to introduce significant levels of drought tolerance into key Asian maize germplasm, resulting in positive impact in diverse environments.
Climate change, declining soil fertility and other environmental stresses affect crop health and production in less developed regions threatening the food security of millions, especially in sub-Saharan Africa. Lack of access to seed and other inputs, underdeveloped markets, and low investment in research and extension worsen farmers’ marginalization. When recurrent droughts in sub-Saharan Africa (SSA) ruin harvests, lives and livelihoods are threatened and destroyed. The situation may become even worse as climate change progresses. Developing, distributing and cultivating drought tolerant maize varieties is a highly effective method of reducing vulnerability, food insecurity and the damage to local markets accompanying food aid in SSA.