As yield results are examined this fall and winter, keep in mind some good guiding principles.

Multiple Locations – data from a single location is only a snapshot of performance and may not provide a complete picture of a product’s potential.  Weather, insects, disease and plant populations are just a few variables that will affect product performance.  If data allows, screen multiple years of data.

Multiple Management Locations – field management will also affect performance.  When was the crop planted? What is the rotation? How much tillage was done? Was an insecticide used? What were the timings of herbicide applications? Do the products contain the same trait packages? Are the populations the same?

Large Plots – with many entries, field variability and other factors come into play that can mask product performance.  A plot with more than 8 entries should have a check product that allows for referencing.  Compare the yield of a product to the check.  A good practice would be to have a second replication at the same site. 

Narrow Plots – plots that are narrow (few rows) may skew the performance of hybrids. Short hybrids can be negatively affected when bordered by taller corn resulting in a possible decrease in yield.  Taller corn bordered by shorter does not increase the yield. 

Statistical Differences – although most plots don’t provide enough data to allow for statistical analysis, it would be beneficial to assess what the same product is yielding from pass to pass. Even in optimal conditions, you can see large swings of bushels per acre.  If you saw an 8 bushel/ac difference from the same hybrid from pass to pass, you could potentially see a -8 to +16 bu/ac disadvantage or advantage on a different product assuming they are equal competitors.  Multiple replications create more sound data and allow for statistical analysis.

Kirk Van Will, CCA-ON, Maizex Seeds Yield Specialist, West Middlesex & Lambton Counties
Twitter: @KirkVanWill