"Although the scientific data on genetically engineered crops and the legal framework to support their use in Africa are several years away, Shah said the Gates Foundation intends to pursue those options.

"We don't want to take anything off the table," Shah said. "Over time we will explore and use those types of technologies."

This worries Joshua Machinga, a Kenyan farmer who works with the nonprofit Common Ground Program. Farmers share local seeds with other farmers and cannot afford to buy seeds, let alone more expensive transgenic varieties that often require fertilizer and pesticide, he said.

"People do not know the hidden agenda behind it," he said, "that once they get the high-yielding seed, they have to keep buying it. Once you get in the system, then getting out becomes difficult." Doug Gurian-Sherman, senior scientist with the Union of Concerned Scientists, said that while genetically modified crops might work in some situations, it's unwise to devote limited attention and resources to unproven technology when basic things like roads and storage and distribution are underfunded.