Data are then averaged for hybrids in tests over two, three, four and five years in each maturity zone. These longer term averages are the most valuable because they show consistency in performance in a range of conditions. Seed companies also conduct many trials. These are of greatest value for comparing hybrids being sold by the company. To give reliable information such tests should include at least three replications of each hybrid.
Results are more meaningful if they are averaged over several locations.
Yields from single plots or fields are of little value for comparing yields whether machine harvested or not. They are valuable, however, for observations on maturity and plant characteristics. Farmer testing also is helpful. Many farmers get some seed of a few promising hybrids in their area and set up their own tests. To provide a basis for sound decisions, farmer tests must be randomized and replicated.