A difference of 23 bushels per acre in yield was found between two samples of corn grown side by side in the same plot in south central Iowa in the 1924 yield test. While such a difference represents the maximum found in the yield test, it is no doubt a common difference which could be found between different strains grown in different communities throughout the cornbelt.
Iowa Corn and Small Grain Growers' Association; Farm Crops Section, Iowa Agricultural Experiment Station; and Office of Cereal Investigations, Bureau of Plant Industry, United States Department of Agriculture, "Iowa Corn Yield Test, Results of 1924 Tests, Plans for 1925 Tests" (1924). Iowa Corn Yield Tests. 8.