With a multimillion-dollar boost from the Gates Foundation, the U.N. food aid agency announced Wednesday it plans to jump-start markets across Africa and elsewhere to give small-scale farmers a chance to rise above subsistence living.

UNITED NATIONS — With a multimillion-dollar boost from the Gates Foundation, the U.N. food aid agency announced today it plans to jump-start markets across Africa and elsewhere to give small-scale farmers a chance to rise above subsistence living.

In 21 countries, 15 in sub-Saharan Africa, the World Food Program will work to develop farmer cooperatives, long-term contracts and other means whereby the U.N. agency will buy corn, wheat and other food crops from smallholders for distribution through its $1-billion-a-year aid program.

"Developing new ways for WFP to purchase food locally represents a major step toward sustainable change that could eventually benefit millions of poor rural households," Microsoft Corp. co-founder Bill Gates said at a joint news conference with African presidents and the WFP leadership.

Although WFP buys 80 percent of its food in developing countries, only a fraction comes directly from small farmers.

Road access to their farms is difficult, their productivity is low, and those who do sell surplus depend on middlemen offering low prices. Many consequently grow only for subsistence, for family consumption.

"Sixty-seven percent of the homesteads in Uganda are subsistence farmers. That is all idle potential," Ugandan President Yoweri Museveni, here for the annual U.S. General Assembly session, told reporters.

The Bill and Melinda Gates Foundation has committed $66 million and the U.S.-based Howard G. Buffett Foundation $9 million to the new, five-year "Purchase for Progress" program.

The donations will underwrite WFP "capacity building" and studies of market and farming conditions that vary from country to country, depending on crops and local customs, from Guatemala and El Salvador in Central America, to Tanzania and Ethiopia in East Africa.

Capacity building could include training programs and infrastructure, such as food storehouses, said WFP spokeswoman Laura Melo.

The program partners estimated Purchase for Progress would "significantly increase" the income of at least 350,000 farmers in the 21 pilot countries. But WFP Executive Director Josette Sheeran said this was just a beginning.

"The goal is to learn from this," she told reporters, "and then to apply that over all of WFP's local purchases."