In Purdue University Corn Performance Trial data, the company that topped the test at Shelburn, Ind., for late-maturing corn hybrids also had a second hybrid in the top half, and two hybrids in the bottom 10% of the same trial.
At the same time, even though the company had a corn variety that topped the plot at the 90% confidence level, it was not significantly better than the seven next hybrids that yielded less. In other words, the top eight corn varieties might all have won at a different time and place. Or at least you're not 90% sure that the difference among this group is due to differences in genetic potential and not experimental error.
"No company is going to win every time," says Dave Nanda, consultant for Seed Consultants, Inc., and a retired plant breeder. "Every hybrid they have also isn't going to perform well in all tests. What you're looking for are hybrids that are consistently in the top tier of hybrids in tests at multiple locations."
Ideally the tests would also be over multiple years, Nanda says.
So why do companies pay to enter corn varieties in plots if they don't think they will be winners? There are various reasons to have different hybrids in the line-up, experts say. One might not be a top yielder very often, but might have very good disease resistance. If the disease hits it may perform well and be what a farmer in a disease-prone area needs.
On the other hand, if it is not very tolerant to a certain disease, and this year happened to be the year for that disease, it may have been shut down early. In another year it might do much better in the same test with the same group of hybrids.
That happened to some hybrids this year since northern corn leaf blight, not a threat every year, was rampant in some areas, Nanda says.