Yields from this year’s corn crop and test plots will likely play a big role in which hybrids you decide to plant next year.

Five things to do when evaluating yield data from your own test plots or others are:

GOOD DATA? Make sure the yield numbers you base your hybrid selections on next year truly reflect the hybrid’s genetic potential.

1. Choose to use data from well-executed plots. Choose locations that minimize variation due to drainage, tillage, fertility, chemical application, soil type, irrigation patterns, etc. Try to ensure that each hybrid strip has an equal chance to win the plot. If the topography varies, strips should be planted at right angles to sources of variation. Compare hybrids in the same field with the same recent rotational history. Strips should be at least 100 feet from tree rows, and first and last strips must have at least two rows of corn as a buffer. Yield data should not be collected from strips that have been affected by sprayer wheel tracks, animal feeding or other factors that affect one or more strips more than others.

Within each location, the same planting date, fertility, seed treatments, weed and pest control, tillage, combine, weighing device, and lack or presence of border rows should be used. At each location, test strips should be at least six rows wide and 500 feet long, and no test location should be greater than eight strips. Location final stand count differences should be minimal.

2. Make a valid hybrid comparison. Match technology segments. Maturities should be within five days of each other and trait packages should be equivalent. Comparing an insect-resistant product and a conventional (non-insect-resistant) product does not help determine the genetic differences between base genetics if insect pressure affects the performance.

3. Make a valid conclusion. Minimize the number of hybrids being compared. The chance of finding the best hybrid decreases as the number of hybrids per plot increases. Being able to accurately pick the best of two or three hybrids is much more certain than trying to pick the best in a group of 10 or more. Make sure to evaluate not only yield, but also harvest moisture. Harvest moisture is a profitability factor and also an indicator of true maturity.

4. Beware of small yield differences. The smaller the yield differences between products, the more plots you should consider. Even with an average yield difference of 6 bushels per acre between two corn hybrids, to be 90% sure the best hybrid is the one you’ve selected requires results from 30 locations.

5. Recognize that next year will not be the same as this year. Using multiple locations over multiple years is highly recommended. Using a single plot is interesting for local companies and provides a great history, but to truly predict future performance with unknown growing conditions, use a minimum of 10 or more plots to compare the same products. Look at multiple years of data or different environments to check on consistency of products under different conditions. As you analyze yield data after harvest, keep in mind that performance data from multiple locations — and from several years, if available — is the most accurate predictor of future hybrid performance. It’s impossible to predict growing conditions for the next year, so it is very important to use a large selection of plots from different growing conditions to ensure that future possibilities get included. In some cases, just knowing you had extremely abnormal growing conditions locally is enough to reduce a plot’s importance in decision-making.

Hybrid selection is one of the most important decisions you make on your farm each year; be sure you give it the consideration and care it deserves.

Fore, Mentor, Minn., is a DuPont-Pioneer agronomist.