December, 1996


Joe Lauer, Keith Hudelson and Pat Flannery


A hybrid corn evaluation program is conducted by the University of Wisconsin ExtensionMadison and College of Agricultural and Life Science, in cooperation with the Wisconsin Crop Improvement Association, to provide unbiased performance comparisons of hybrid seed corn available in Wisconsin. These trials evaluate corn hybrids for both grain and silage production performance.

Seasonal precipitation and temperature at the 1996 sites are shown in Table 2. The eastern half of the state was wet during May resulting in later than normal corn planting dates; only 65% of the corn was planted by May 26 compared with the 5-yr. average of 81% (Wisconsin Agricultural Statistics Service). The overall growing season was cooler than normal, accumulating 92% of normal growing degree days. Dry weather in late August and September allowed some of the corn to "catch up," but the late planting dates combined with a cooler than normal growing season resulted in corn with high grain moisture levels and slightly lower than normal yields at the test locations. Widespread frost occurred on October 3. European Corn Borer (Ostrina nubilalis) populations were high in the spring and caused some first generation damage. As the season progressed, populations decreased and were low in the fall.


In 1996, grain and silage performance trials were planted at thirteen locations in four production zones. Both seed companies and university researchers submitted hybrids. Companies with hybrids included in the 1996 trials are listed in Table 1. At most locations trials were divided into early and late maturity trials, based on the hybrid Relative Maturities provided by the companies. The specific Relative Maturities separating early and late trials are listed below.

Southern Zone: Arlington, Janesville, Lancaster Early Maturity Trial: 105 day or earlier Table 4
Late Maturity Trial: later than 105 day Table 5
South Central Zone: Fond du Lac, Galesville, Hancock (irrigated) Early Maturity Trial: 100 day or earlier Table 6
Late Maturity Trial: later than 100 day Table 7
North Central Zone: Chippewa Falls, Marshfield, Seymour, Valders Early Maturity Trial: 90 day or earlier Table 8
Late Maturity Trial: later than 90 day Table 9
Northern Zone Spooner (three sites), White Lake Table 10
Ashland Table 17
Southern Zone Arlington and Lancaster Early Maturity Trial: 110 day or earlier Table 11
Late Maturity Trial: later than 110 day Table 12
South Central Zone: Fond du Lac and Galesville Early Maturity Trial: 105-day or earlier Table 13
Late Maturity Trial: later than 105-day Table 14
North Central Zone: Marshfield and Valders Early Maturity Trial: 95day or earlier Table 15
Late Maturity Trial: later than 95day Table 16
Northern Zone Ashland Table 18


The seedbed at each location was prepared by either conventional or conservation tillage methods. Fertilizer was applied as indicated by soil tests. Herbicides were applied for weed control and supplemented with cultivation when necessary. Corn rootworm insecticide was applied when the previous crop was corn. Information for each location is summarized in Table 3.


Plots were planted with a corn planter except for trials at Ashland in the Northern Zone, which were handplanted. Tworow plots were planted at all locations except Ashland, where onerow plots were used. Twentytwo foot long plots were over planted and hand thinned to achieve as near a uniform stand as possible. Each hybrid was grown in at least three separate plots (replicates) at each location to account for field variability.


Plots were harvested with a selfpropelled corn combine or shelled with a portable field sheller. Lodged plants and/or broken stalks were counted, plot grain weights and moisture contents were measured and yields were calculated and adjusted to 15.5% moisture.

Wholeplant (silage) plots were harvested using a tractor driven, three-point mounted one-row chopper. At Ashland, plots were handharvested. One row was analyzed for whole plant yield and quality. Kernel milk percent, plot weight, and moisture content were measured, and yields were adjusted to tons/acre dry matter. A sub-sample was collected and analyzed using near infra-red spectroscopy by the Marshfield Forage Analysis Laboratory.


Yield results for individual location trials and for multilocation averages are listed in Tables 4 through 18. Within each trial, hybrids are ranked by moisture, averaged over all 1996 locations conducted in that zone. Yield and moisture data for both 1995 and 1996 are provided if the hybrid was entered previously in the 1995 trials.


Seed companies use different methods and standards to classify or rate the maturity of corn hybrids. To provide corn producers a "standard" maturity comparison for the hybrids evaluated, the average grain moisture of all hybrids which are rated at appropriate relative maturities by the Minnesota Relative Maturity Rating System are shown in each table. This system categorizes corn hybrids into relative maturity groups by comparing harvest grain moisture of evaluated hybrids to moisture of standard hybrids for each group (see Minnesota Relative Maturity Rating of Corn Hybrids, Agric. Extension Service, Univ. of Minnesota, Agronomy No. 27).

Hybrids with lower moisture than a particular relative maturity average are likely to be earlier than that relative maturity, while those with higher grain moisture are most likely later in relative maturity.


Three factors yield, moisture, and standability are of primary importance in evaluating and selecting corn hybrids. A performance index (P.I.), which combines these factors in one number, was calculated for multilocation averages for grain trials. This performance index evaluates yield, moisture %, and lodged stalks % at a 50 (yield) : 35 (moisture %) : 15 (lodged stalks %) ratio.

The performance index was computed by converting the yield, dry matter, and upright stalks values of each hybrid to a percentage of the test average. Then the performance index for each hybrid that appears in the tables was calculated as follows:

(Yield % x 50) + (Dry matter % x 35) + (upright stalks % x 15)


Corn silage quality was analyzed at the Marshfield Forage Quality Laboratory using near infra-red spectroscopy equations derived from previous work of Dr. Jim Coors (UW-Madison). Plot samples were dried, ground and analyzed for crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and in vitro digestibility (IVD). Spectral groups and outliers were checked using wet chemistry analysis. The silage performance indices of milk per acre and milk per ton were calculated using a model derived from the spreadsheet entitled, "MILK95," developed by Drs. Dan Undersander, Terry Howard and Randy Shaver (J. Prod. Agric 6:231-235). The spreadsheet approximates a balanced ration meeting animal energy, protein, and fiber needs based on forage quality (in vitro digestibility basis). The spreadsheet is based on equations predicting intake and animal requirements from data derived from National Research Council (NRC) tables on nutrient requirements of dairy cattle (1978, 1989). The values of milk per acre and milk per ton are based on a standard cow weight and level of milk production (1350 lb body weight and 90 lb/d at 3.8% fat).


Variations in yield and other characteristics occur because of variations in soil and other growing conditions which lower the precision of the results. Statistical analysis makes it possible to determine, with known probabilities of error, whether a difference is real or whether it might have occurred by chance. Use the appropriate LSD (least significant difference) value at the bottom of the tables to determine true differences.

Least significant differences (LSD's) at the 10% level of probability are shown. Where the difference between two selected hybrids within a column is equal to or greater than the LSD value at the bottom of the column, you can be sure in nine out of ten chances that there is a real difference between the two hybrid averages. If the difference is less than the LSD value, the difference may still be real, but the experiment has produced no evidence of real differences. Hybrids which were not significantly lower in performance than the highest hybrid in a particular test are indicated with an asterisk.


The results can be used to provide producers with an independent, objective evaluation of performance of unfamiliar hybrids, promoted by seed company sales representatives, compared to competitive hybrids.

Below are suggested steps to follow for selecting topperforming hybrids for next year using these trial results:

  1. Use multi-location average data in shaded areas. Consider single location results with extreme caution.
  2. Begin with trials in the zone(s) nearest you.
  3. Compare hybrids with similar maturities within a trial. You will need to divide most trials into at least two and sometimes three groups with similar average harvest moisture within about 2% range in moisture.
  4. Make a list of 5 to 10 hybrids with highest 1996 Performance Index within each maturity group within a trial.
  5. Evaluate consistency of performance of the hybrids on your list over years and other zones.
    • Scan 1995 results. Be wary of any hybrids on your list which had a 1995 Performance Index of 100 or lower. Choose two or three of the remaining hybrids which have relatively high Performance Indexes for both 1995 and 1996.
    • Check to see if the hybrids you have chosen were entered in other zones. (For example, some hybrids entered in the Southern Zone Trials, Tables 4 and 5, are also entered in the South Central Zone Trials, Tables 6 and 7).
    • Be wary of any hybrids with a Performance Index of 100 or lower for 1995 or 1996 in any other zones.
  6. Repeat this procedure with about three maturity groups to select topperforming hybrids with a range in maturity, to spread weather risks and harvest time.
  7. Observe relative performance of the hybrids you have chosen based on these trial results in several other reliable, unbiased trials and be wary of any with inconsistent performance.
  8. You might consider including the hybrids you have chosen in your own test plot, primarily to evaluate the way hybrids stand after maturity, drydown rate, grain quality, or ease of combineshelling or picking.
  9. Remember, you don't know what weather conditions (rainfall, temperature) will be like next year. Therefore, the most reliable way to choose hybrids with greatest chance to perform best in 1996 on your farm is to consider performance in 1995 and 1996 over a wide range of locations and climatic conditions.

You are taking a tremendous gamble if you make hybrid selection decisions based on 1996 yield comparisons in only one or two local test plots.


The information in this report is also available on the internet at Hybrid performance for the last 10 years can be summarized using SELECT! which can be downloaded from the above internet address. The tables are also available in downloadable self-extracting zipped files for Excel 5.0.

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