When grown on the same soil and under exactly the same conditions one corn outyielded another corn of the same general variety by sixteen bushels per acre in the 1922 state yield test. There are important differences in the yields secured from different varieties of corn. There are as great differences in the yield secured from different strains of the same variety of corn as between distinctly different varieties adapted to the same locality. Recognizing these fact the Iowa Corn Yield Te was inaugurated in 1930 by the Iowa Corn and Small Grain Growers' has been continued during the past thre years.