Bill Gates, speaking at a World Food Prize forum in Iowa on Thursday, told global food leaders that an "ideological wedge" threatens his global effort to help farmers.

Gates and his wife have focused in recent years on helping alleviate hunger and poverty by giving small farmers the tools to produce more. The Gates Foundation has given more than $1.4 billion to agricultural development, and on Thursday announced nine new grants worth $120 million aimed at raising yields and farming expertise in the developing world.

Sub-Saharan Africa is the most under-nourished region in the world, with almost 42% surviving on less than $1 per day. A combination of decades-long drought, regional conflict, and a burgeoning population contribute to the world's worst hunger situation.

The $120 million announced on Thursday is intended to help develop genetically modified crops that are more drought-resistant and productive in marginal conditions. Nitrogen-fixing legume crops, sorghum and millet, and sweet potatoes are all undergoing genetic experimentation sponsored by the Gates Foundation.

Genetically modified(GM) crops have been a topic of intense agricultural debate since their creation. GM crops undergo genetic manipulation in a laboratory, usually for the purpose of increasing crop yield or pest resistance. In many countries in Europe, vendors are legally required to clearly label GM foods; there is skepticism about the science behind genetic manipulation.

Many believe that GM crops will lead to even greater crop homogenization and threaten the stability of the global food supply. Wendell Berry, one of America's most prominent agricultural researchers, told the Washington Post, “The inevitable aim of industrial agri-investors is the big universal solution... And the kind of agriculture we’re talking about that leads to food security and land conservation is locally adapted agriculture.”

In his speech on Thursday, Gates rejected what he saw as a false dichotomy between sustainability and productivity, but avoided mentioning genetic modification. “The technology and new approaches that are transforming agriculture in other parts of the world can be applied in new ways, and help Africa flourish too,” Gates said. “This global effort to help small farmers is endangered by an ideological wedge that threatens to split the movement in two. On one side is a technological approach that increases productivity. On the other side is an environmental approach that promotes sustainability. It's a false choice, and it's dangerous for the field.”

The World Food Prize honors people who have contributed to ending hunger worldwide. More about the forum and Gates' speech can be found here.