New Orleans, July i.- Duncan F. Kenner, the veteran sugar planter, died suddenly yesterday morning of heart-disease. Mr. Kenner was a native of this city and was seventy-four yeavs of age. He leaves a fortune estimated at tl, 000,000. He served in Congress, was State Senator and was a candidato for United States Senator, but was defeated. He wa3 president 'of the Louisiana Jockey Club, and was selected by Jeffer3on Davis, in November, 1S64, as special commissioner to England and Franca.