Francis C. Byrnes, 81, an agricultural communications specialist who did work for nonprofit organizations and governmental agencies, died of liver cancer July 5 at his home in Reston.

While working for the New York-based Rockefeller Foundation from 1963 to 1983, Mr. Byrnes was assigned to development assistance organizations that included the International Rice Research Institute, International Center for Tropical Agriculture and International Agricultural Development Service.

He helped train foreign officials on methods of disseminating information about crop yields and other aspects of agriculture.

He also wrote reports on the effects of agricultural research and development programs on poor communities in developing countries.

After his retirement in 1983, he was a consultant to organizations that included the U.S. Agency for International Development, the United Nations and the Asian Development Bank.

Most recently, he was a senior associate of the Winrock International Institute for Agricultural Development.

Mr. Byrnes was born in Vail, Iowa. He was a graduate of Iowa State University and received a doctorate in communications from Michigan State University.

As a young man, he was an information specialist with the Agriculture Department. He was also an editor and correspondence course director at Ohio State University and deputy director of an agricultural communications project at Michigan State.

His wife, Ethel Belle Byrnes, died in 1984.

Survivors include three children, Kathryn Stephens of Herndon, Kevin Byrnes of Richmond and Kerry Byrnes of Reston; a brother; a sister; and three grandchildren.