By Jeff Coulter, Extension Corn Agronomist
Results from the 2010 University of Minnesota corn grain and silage hybrid trials are available online at the following links:
These trials were conducted at multiple locations across Minnesota to provide unbiased and replicated information on the performance of numerous hybrids for growers and agronomists.
When selecting hybrids, it is best to choose hybrids that perform well over multiple locations in a region. Consistent performance over multiple locations with different soil and weather conditions is critical because we cannot predict next year's growing conditions, and a hybrid that performs well over multiple environments will have a high potential of performing well next year. In the past, the performance of a given set of hybrids could be evaluated over multiple years at a given location, but that is less realistic now because today's lifespan for a typical corn hybrid is just a few years.
To reduce risk, Minnesota growers are encouraged to select hybrids based on trial results from multiple sources, including universities, the Minnesota Corn Growers Association, seed companies, and on-farm strip trials. Results from unbiased and replicated trials that include multiple hybrids from different companies are of particular importance.
Click on the links below for results from additional corn hybrid trials:
Considerations for Grain Hybrid Selection:
· Hybrid selection begins with maturity. In addition, remember that the 2010 growing season was unusually warm and long in Minnesota. 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 freeze (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 at: http://www.extension.umn.edu/distribution/cropsystems/M1276.html
· 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 at: http://www.extension.umn.edu/distribution/cropsystems/M1276.html
· 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 a key trait for ensuring that the grain produced is harvestable.
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 guideline is that hybrids planted for silage should be 5 to 10 days longer in RM 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.
· Select hybrids that have a range in RM, as this widens the harvest window. Harvesting at the correct moisture level is critical for producing high quality silage, and if missed, can negate the benefits of good hybrid selection. The importance of widening the harvest window was seen across Minnesota in 2010, as corn matured so rapidly under warm air temperatures that many growers had difficulty getting their corn chopped before it was too dry. Planting hybrids with a range in maturity also widens the pollination window, thereby reducing the risk that one's entire crop will experience hot and dry conditions during pollination.
· Other important agronomic considerations when selecting silage hybrids include herbicide and insect resistance for the given cropping system, and tolerance to drought and disease. Selecting a hybrid with a high rating for drought tolerance may be useful on droughty soils, in dry regions, or in a lower-rainfall area where a previous crop of alfalfa has depleted subsurface soil moisture. Standability, however, is less important for silage hybrids than grain hybrids due to the earlier time of harvest.
· Since corn silage is an energy source for animal performance, producers should consider both silage quality and yield when selecting hybrids. These are represented with the variables milk per ton and milk per acre, 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 is estimated from forage analyses for crude protein (CP), neutral detergent fiber (NDF), NDF digestibility (NDFD), starch, and non-fiber carbohydrate.
· Milk per acre is a single term that represents both silage yield and quality, and is heavily influenced by silage yield. Milk per acre is calculated by multiplying milk per ton with silage dry matter yield. The goal is to identify hybrids with high values for both milk per ton and milk per acre. These hybrids produce high quality forage and high silage yield, and are thus most profitable. Once a suitable group of hybrids has been identified based on milk per ton and milk per acre, further selection within this group can be based on specific forage quality and agronomic traits. Consulting with a livestock nutritionist during the hybrid selection process helps to ensure that selected hybrids will have the necessary nutritive value for your herd.