Considerations For Evaluating Hybrids
Several Factors to Consider When Using Yield Data to Select Hybrids For Next Season
Hybrid performance one year often plays a significant role in decisions about which hybrids to plant the following year. Valid yield data practices help in making better decisions. There are several important considerations whether planning your own test plot or looking at results from others.
Choose well executed plots
When making on-farm comparisons, evaluate locations for irregularities such as drainage and ponding, variation in fertilizer or manure applications, dead furrows, and areas of compaction or wheel tracks. Compare hybrids in the same field with the same recent rotational history. If possible, select a location that minimizes soil variation. Identify location by soil-type map and limit or block test width and length to uniform soil.
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 four rows wide and 500 feet long, and no test/location should be greater than eight strips. Location final stand count differences should be minimal.
Make a valid hybrid comparison
Match technology segments. Evaluate like products with one another. 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.
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.
Beware of small yield differences
The smaller the yield differences between products, the more plots that should be considered. Even with an average of 6-bushel-per-acre yield difference between two corn hybrids, to be 90% sure the best hybrid is the one you have selected, it takes results from 30 locations to make sure the difference is "real," and not just chance.
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 comparisons 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.
When looking at 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. One can’t 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 actually reduce a plot’s importance in decision making.
Hybrid decision 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.