Marion Eugene Whitten, 91, a retired Agriculture Department research chemist who sang tenor in church groups, died of cancer Aug. 26 at his home in Arlington.

Mr. Whitten retired in 1973 after a 27-year career, spent mostly in the market quality research division of the Agricultural Research Service. There, he supervised development of methods for detecting the naturally occurring toxins in crops known as aflatoxins.

He also was an accomplished musician and singer who performed professionally as a soloist at Constitution Hall and the National Gallery of Art, among other places.

Mr. Whitten was a tenor soloist at Metropolitan Memorial United Methodist Church in Washington and the Washington Hebrew Congregation.

He was born in Corsicana, Tex., and graduated from Texas A&M University in 1929.

He directed laboratory operations for several vegetable oil companies in Dallas before being called to active military duty in 1941.

Mr. Whitten, who received a commission in the Army Reserve upon his graduation from Texas A&M, served in World War II as a chemical officer in the 3rd Armored Division in France, Belgium, Germany and England. He continued in the Army Reserve, retiring as a colonel in 1968.

Survivors include his wife, Neva I. Whitten of Arlington; four children, Reed Whitten of Cary, N.C., Kathleen Clements of Arlington, Robert Whitten of San Francisco and Anne Whitten of Annandale; a sister; and three grandchildren.