To determine how varieties will perform from year to year across counties a method of averaging yields was developed. A variety was selected that was planted in a number of tests and the average yield was determined. The difference from that average was then subtracted or added to all varieties in the test. This adjusted yield was then used to determine the performance of each variety.

This method of adjusting yields became difficult to use as varietes have changed. This document serves more as a historical reference for varieties that were planted in the 1989 to 2000 time frame. New varieties are being tested and that data is going into a data base that can be referenced by producers that have an internet connection.