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Column: Limit risk when selecting corn hybrids

ST. PAUL -- You can reduce risk when selecting corn hybrids by using information from many sources, including universities, grower associations, seed companies and on-farm strip trials. Results from unbiased, replicated trials are especially important.

Selecting grain hybrids:

- Hybrid selection begins with maturity. Identify an acceptable maturity range based on the number of growing degree days required for a hybrid to reach physiological maturity (black layer). Selected hybrids should reach maturity at least 10 days before the first average frost to allow time for grain dry-down and to provide a buffer against a cool year or late planting.

- Plant multiple hybrids of varying maturity to spread risk and widen the harvest interval.

Full-season grain hybrids do not consistently out-yield midseason hybrids in Minnesota. There is more variability in yield among hybrids within a given relative maturity rating than there is between maturity groups.

- Hybrids should also be selected for standability, disease tolerance, emergence, and the need for transgenic resistance to insects and herbicides within a given production system. Standability is critical for ensuring that the grain produced is harvestable. Since corn has a narrow optimum plant population, unharvestable ears due to stalk and root lodging will have a large impact on yield.

Selecting hybrids for silage:

- Again, maturity is one of the first things to consider. Longerseason hybrids tend to have higher silage yields. A general rule of thumb is that hybrids planted for silage should be 5 to 10 days longer in relative maturity than the hybrids planted for grain.

- Consider planting hybrids with a range in maturity, as this reduces the probability that the entire crop will experience hot and dry conditions during pollination. This can also widen the harvest window.

- Other important considerations include standability, drydown, herbicide and insect resistance, and tolerance to drought and disease. If hybrids with strong ratings for stay-green are selected, growers should be aware that whole-plant moisture will likely be higher than normal when harvested according to kernel stage.

Since corn silage is an energy source for animal performance, producers should consider both yield and quality when selecting hybrids.

More details, including 2009 University of Minnesota corn grain and silage trials results, are available at

Or, for this information as well as new variety trial results for other Minnesota crops, visit the variety trial pages on the Minnesota Agricultural Experiment Station Web site at