Focus on improved maize for African soils

DR KINGSTON MASHINGAIDZE, ARC-GRAIN CROPS INSTITUTE

Maize (Zea mays L.) is the most widely grown staple food crop in sub-Saharan Africa. Maize is an important lifeline in the Southern African Development Community (SADC) where over 150 million people annually consume close to 13 million metric tonnes or 86 kg per capita of this staple.

Maize consumption levels range from 85 kg to 140 kg per capita per year in Kenya, Lesotho, Malawi, South Africa, Zambia and Zimbabwe (FAOSTAT 2006, 2003 - 2005 average).

Among low-income groups, who cannot afford more expensive foods, such as bread, milk or meat, maize is the principal source of both calories and protein. For smallholder farm families, low maize yields jeopardise hope for the future.

Families lacking a marketable surplus also lack the cash to pay school fees, and malnourished children cannot develop to their full potential. Increased yields are needed both to meet their basic needs and to acquire assets as a reserve for times of crop failure.

With maize occupying over half the cereal production area in more than 50% of all sub-Saharan African (SSA) countries, maize production has strategic importance for food security and for the socio-economic stability of the region.

The Green Revolution, which raised average rice yields in South Asia by 80% from 1973 -1977 to 2003 - 2007, has largely by-passed smallholders in SSA, where maize yields increased by only 25% over the same period. Failure to improve productivity in Africa’s most important staple crop, has contributed to high local grain prices, food shortages, and an increase in the number of Africans in extreme poverty from 200 million in 1981 to 380 million in 2005.

The IMAS project

Maize yields of smallholder farmers in sub-Saharan Africa are a fraction of those in the developed world, due mainly to the region’s poor soils, drought and farmers’ limited access to fertiliser and improved maize seed.

Fertiliser is expensive and getting more so, especially for African farmers. Because of high transportation costs due to poor roads and rail systems in their countries, African farmers often pay two to six times the world average price for fertilisers. As a result, they apply far less than the amounts needed to produce high yielding crops.

Farmers in sub-Saharan Africa fertilised their crops at an average rate of 9 kg per hectare in 2002/2003, compared with 100 kg and 73 kg per hectare in South Asia and Latin America, respectively (Crawford, Jayne and Kelly, 2005).

Of that small amount, often less than half is taken up by the crop; the rest is leached deep into the soil where plants cannot recover it or is otherwise lost. A Green Revolution in Africa will need more fertiliser, better soil management and low nitrogen tolerant varieties (cultivars).

The Improved Maize for African Soils (IMAS) project is a public-private partnership aimed at developing and deploying royalty-free, low nitrogen tolerant maize cultivars for use by smallholder farmers in sub-Saharan Africa. The cultivars will be developed using conventional breeding, marker-assisted breeding and transgenic agricultural biotechnology.

The project partners are the Agricultural Research Council (ARC), International Maize and Wheat Improvement Centre (CIMMYT), Kenya Agricultural Research Institute (KARI) and Pioneer, a DuPont Business.

Vision of success over ten years

Launched in February 2010, the IMAS project is developing maize varieties that can take up and more efficiently use nitrogen from severely depleted soils, as well as making better use of the little fertiliser African farmers apply.

Partners are applying large-scale, conventional crossing and field selection, along with advanced science, such as DMA markerassisted breeding, the identification and use of high-impact genes directly from maize as well as transgenics.

Farmers should have access to varieties developed through conventional breeding in 2014, and these will offer a 20% yield advantage over varieties at the start of the project. Improved varieties developed using DNA marker-assisted breeding techniques are expected within seven to nine years and those containing transgenic traits are expected to be available in approximately ten years, pending product performance and regulatory approvals. See Figure 1.

The yield advantage for farmers of IMAS varieties developed using all three of the above approaches, should be at least 50%. Delivery of the new varieties will directly benefit some 60 million resource-poor farmers and their families in eastern and southern Africa and beyond.

Low nitrogen tolerant varieties from IMAS are likely to be incorporated into the Drought Tolerant Maize for Africa (DTMA) and Water Efficient Maize for Africa (WEMA) projects, so that farmers can eventually obtain maize seed that yield more under both drought and in infertile soils.

Improved incomes and food security from their use will free up resources for farmers to adopt integrated soil fertility management practices, including combined use of chemical and organic fertilisers. The Project will seek complementary partnerships with other initiatives to ensure knowledge transfer of best practices in agronomy, conservation agriculture and crop rotations.

For more information, contact Dr Kingstone Mashingaidze at
(018) 299-6100/6356 or MashingaidzeK@arc.agric.za.