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Tuesday, December 1, 2009

Corn Hybrid Selection: Practical Considerations and Results from 2009 Grain and Silage Trials

By Jeff Coulter, Extension Corn Agronomist

Hybrid Trial Results

Results from the 2009 University of Minnesota corn grain hybrid trials are now available at:

Results from the 2009 University of Minnesota corn silage hybrid trials are now available at:

These trials were conducted at multiple locations across Minnesota by the University of Minnesota Agricultural Experiment Station - to provide unbiased information for use by corn growers when selecting hybrids. A paper copy of these trial results will be available at local Extension offices in late December. These trial results are also available as a special report published each December in Agri-News.

Yield stability over multiple locations is critical, since we cannot predict next year's growing conditions. To reduce risk, hybrid selection should be based on information from multiple sources, including universities, grower associations, seed companies, and on-farm strip trials. Results from unbiased and replicated trials are of particular importance.

Past grain and silage trial results from the University of Minnesota are available at Minnesota Agricultural Experiment Station

Minnesota Corn Growers Association grain hybrid trial results from 2009 and previous years are available at:

Links to corn hybrid trial results from 2009 and previous years from neighboring universities are listed below:

Thumbnail image for Thumbnail image for IMAG0066.jpg
The 2009 growing season was unusual and presented growers
with numerous challenges this fall. Think carefully about
hybrid selection for 2010 to limit risk and ensure success.

Considerations for Grain Hybrid Selection

  • Hybrid selection begins with maturity. Identify an acceptable maturity range based on the number of growing degree days (GDDs) required for a hybrid to reach physiological maturity (black layer). Selected hybrids should reach maturity at least ten days before the first average frost (32⁰F) to allow time for grain dry-down and to provide a buffer against a cool year or late planting. Detailed information about the number of GDDs available for corn production for multiple locations and various planting dates, along with information on the relationship between GDDs and corn relative maturity (RM) is available in the article Selecting corn hybrids for grain production
  • Plant multiple hybrids of varying maturity to spread risk and widen the harvest interval.
  • Very full-season grain hybrids do not consistently out-yield mid-season hybrids in Minnesota. There is more variability in yield among hybrids within a given RM rating than there is between maturity groups. Detailed information on corn grain yields and harvest moisture for various RMs across Minnesota is available in Selecting corn hybrids for grain production
  • Hybrids should also be selected according to agronomic traits such as 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. In a hybrid trial conducted in northwest Iowa in 2005 where severe lodging was present, each 1% increase in lodging reduced grain yield by an average of 0.5 bushels per acre (Elmore et al., 2006).

Considerations for silage hybrid selection

  • One of the first things to consider when selecting silage hybrids is maturity. Longer-season 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. However, these later-maturing hybrids may not be the best choice for a producer wanting early silage or the option to harvest the corn for grain.
  • Consider planting hybrids with a range in maturity, as this reduces the probability that one's entire crop will experience hot and dry conditions during pollination. This can also widen the harvest window, which is important for timely harvest at the appropriate moisture level. However, silage that is custom harvested within a short period of time may require a narrower range in maturity to reduce variation in harvest moisture. Harvesting at the correct moisture level is key for producing high quality silage, and if missed, this can negate the benefits of good hybrid selection.
  • Other important agronomic considerations when selecting silage hybrids 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. However, the numerous variables representing yield and quality can make hybrid selection a little overwhelming. Two key variables for dairy producers to consider are milk per acre and milk per ton, both of which are calculated using the MILK2006 spreadsheet developed by the University of Wisconsin. Milk per ton is an overall indication of silage quality, and it is estimated from forage analyses for crude protein (CP), neutral detergent fiber (NDF), NDF digestibility, starch, and non-fiber carbohydrate. Milk per acre is a single term that represents both silage yield and quality. Milk per acre is calculated by multiplying milk per ton with silage dry matter yield.
  • In general, higher NDF values indicate lower intake and animal performance; while higher values for CP, starch, NDF digestibility, and in vitro digestibility imply greater performance potential. While small changes in forage quality can greatly impact milk production, differences in individual quality traits between hybrids that are less than 5% are probably not statistically significant or worth worrying about.


Elmore, R., L. Abendroth, and J. Rouse. 2006. Choosing corn hybrids [Online]. Available at (verified 1 Dec. 2009). Iowa State Univ., Ames.

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