Kenyan scientists develop new insect-resistant maize variety

Kenyan scientists from the International Maize and Wheat Improvement Centre (CIMMYT) and the Kenya Agricultural Research Institute (KARI) have developed a new maize variety that is significantly resistant to the larger grain borer, which attacks the stored maize crop.

In just six months, this insect pest can destroy more than a third of stored maize. The new maize variety will benefit farmers in Kenya by reducing the levels of postharvest maize losses and help improve Kenya’s food security by reducing dependence on imported maize.

“This is a major achievement and will be of great help to farmers in Kenya and more than 20 African countries, who have had few options to control this pest for nearly 30 years,” says Stephen Mugo, the CIMMYT maize breeder who led the CIMMYT-KARI collaboration.

The larger grain borer is native to Central America and was first observed in Africa in Tanzania in the late 1970s. It is thought that the borer may have inadvertently been introduced to the continent via a shipment of maize food aid during the 1979 drought in eastern Africa.

Previous attempts at biological control of the borer using its natural predators have been largely unsuccessful. Researchers therefore studied the habits of the borer, hoping to find ways to reduce the damage it causes. They discovered that it needs a solid platform, such as that provided by maize kernels still on the cob, before it will bore into a kernel.

Unfortunately farmers in Africa often store maize on the cob, increasing the potential for borer damage. Shelling the maize and storing it off the cob can reduce the damage but postharvest losses are still very high.

This is what makes the newly developed variety, where the resistance lies in the seed, so exciting.

“Having the solution in the seed itself makes adoption much easier for farmers,” says Marianne Banziger, director of CIMMYT’s Global Maize Program.

But Banziger cautions that the insect-resistant maize is not a silver bullet solution to the grain borer problem and strongly recommends that the new variety be used together with other pest-control measures.

CIMMYT researchers found resistance to the borer in the Centre’s germplasm bank, in maize seed originally from the Caribbean. By using conventional plant breeding techniques — crossing the Caribbean maize with maize already adapted to conditions found in eastern Africa — the researchers were able to combine the resistance of the Caribbean maize with key traits valued by Kenyan maize farmers.

The new maize variety will undergo performance trials by the Kenya Plant Health Inspectorate Services (KEPHIS) and other national seed authorities outside Kenya. Testing is expected to take 1-3 years, after which seed of the new maize hybrids and open pollinated varieties will be made available to seed companies for seed production and sale to farmers

Source: The International Maize and Wheat Improvement Centre (CIMMYT)

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