The Iowa corn yield test has been conducted annually since 1920 by the Iowa Corn and Small Grain Growers’ Association in cooperation with the Iowa Agricultural Experiment Station. In 1951 the Iowa Com and Small Grain Growers’ Association was combined with the Iowa Crop Improvement Association. This change became effective July 4, 1951.

The majority of hybrids tested in the Iowa Com Yield Test were entered voluntarily by commercial hybrid corn companies. In addition, several hybrids were tested for the Agronomy (Farm Crops) Department and U.S.D.A. and for the Iowa Crop Improvement Association. The Iowa Crop Improvement Association entries are classified as follows:

a. Hybrids widely grown in each section as determined by a survey of farmers. You will find these hybrids listed in the tables as entered by the Iowa Corn and Small Grain Growers’ Association.

b. Hybrids designated in the 1951 certification handbook as base hybrids. Four hybrids in each section were selected as base hybrids. To be eligible for certification a hybrid must meet certain minimum requirements, when compared with the average performance of the four base hybrids in the appropriate section.

c. Station hybrids entered to establish a performance record to determine eligibility for certification.