
December 2003
A3653
2003 WISCONSIN CORN HYBRID PERFORMANCE TRIALS
GRAIN AND SILAGE
Joe Lauer, Kent Kohn, and Pat Flannery
TESTING PROCEDURE
PRESENTATION OF DATA
HOW TO USE
THESE RESULTS TO SELECT TOP-PERFORMING HYBRIDS
OBTAINING DATA ELECTRONICALLY
PDF Format
Excel Format and Cover
The University of Wisconsin Extension-Madison and College of Agricultural and Life
Sciences conduct a hybrid corn evaluation program, in cooperation with the Wisconsin
Crop Improvement Association. The purpose of this program is to provide unbiased
performance comparisons of hybrid seed corn available in Wisconsin. These trials
evaluate corn hybrids for both grain and silage production performance.
TESTING PROCEDURE
In 2003, 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 2003 trials are listed in
Table 1. In the back of the report, hybrids previously tested
over the past four years are listed. 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.

Map: Wisconsin Relative Maturity Belts and test sites.
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Grain
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Southern Zone
Arlington, Janesville, Lancaster
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Early Maturity Trial: 105-day or earlier
Late Maturity Trial: later than 105-day
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Table 4
Table 5
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South Central Zone
Fond du Lac, Galesville, Hancock (irrigated)
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Early Maturity Trial: 100-day or earlier
Late Maturity Trial: later than 100-day
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Table 6
Table 7
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North Central Zone
Chippewa Falls, Marshfield, Seymour, Valders
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Early Maturity Trial: 90-day or earlier
Late Maturity Trial: later than 90-day
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Table 8
Table 9
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Northern Zone
Spooner (three sites), White Lake
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Table 10
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Silage
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Southern Zone
Arlington and Lancaster
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Early Maturity Trial: 105-day or earlier
Late Maturity Trial: later than 105-day
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Table 11
Table 12
Graph
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South Central Zone
Fond du Lac and Galesville
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Early Maturity Trial: 100-day or earlier
Late Maturity Trial: later than 100-day
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Table 13
Table 14
Graph
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North Central Zone
Chippewa Falls, Marshfield, Valders
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Early Maturity Trial: 90-day or earlier
Late Maturity Trial: later than 90-day
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Table 15
Table 16
Graph
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Northern Zone
Spooner (two sites), Rhinelander
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Table 17
Graph
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GROWING CONDITIONS FOR 2003
Seasonal precipitation and temperature at the trial sites are shown in
Table 2. The southwestern quadrant of Wisconsin was affected by a drought
where little rain fell from mid-July through August. Grain and silage yields were
quite variable. Both grain and silage yields were above normal in northeastern Wisconsin.
Spring planting conditions were good until May 4 after which conditions were cooler
and dryer than average. Plant emergence and stands were above average and the condition
of the crop looked good through the end of July. Corn development was somewhat behind
average due to cool early growing conditions, but development caught up and was
average by mid-July due to hot, dry conditions. Dry, hot weather during pollination
lowered yields in southwestern Wisconsin, especially for late-planted corn and longer-season
relative maturity hybrids. Growing degree unit accumulation was slightly behind
average throughout the entire growing season. Corn silage harvest began earlier
than normal on sites affected by the drought. A killing frost did not occur until
early-October. Plant standability was poor in drought affected trials. During the
fall harvest season, yields were generally good to excellent, and moisture was low
decreasing drying costs.
CULTURAL PRACTICES
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.
PLANTING
A corn planter with cone units was used at all locations. Two-row plots were planted
at all locations. Twenty-five 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.
HARVESTING
Grain: Plots were harvested with a self-propelled corn combine. 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.
Silage: Whole-plant (silage) plots were harvested using a tractor driven,
three-point mounted one-row chopper. 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 dry matter / acre. A sub-sample was collected and
analyzed using near infra-red spectroscopy.
PRESENTATION OF DATA
Yield results for individual location trials and for multi-location averages are
listed in Tables 4 through 18. Within each trial, hybrids are ranked by moisture,
averaged over all 2003 trials conducted in that zone. Yield and moisture data for
both 2002 and 2003 are provided if the hybrid was entered previously in the 2002
trials. A two-year average for yield is calculated using location data for replications.
A hybrid index at the back of this report lists relative maturity ratings,
specialty traits and locations tested for each hybrid.
RELATIVE MATURITY
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 rated
by the Minnesota Relative Maturity rating system are shown in each table. Minnesota
Relative Maturity ratings are rounded to 5-day increments.
The Minnesota Relative Maturity rating system categorizes corn hybrids into relative
maturity groups by comparing harvest grain moisture of a hybrid to the moisture
of standard hybrids for each group (see Minnesota Relative Maturity Rating of Corn
Hybrids, Agriculture Extension Service, University of Minnesota, Agronomy
No. 27). In these Wisconsin results 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.
Maturity ratings can be found in Table 1 where company maturity ratings, Minnesota
Relative Maturity ratings, and Wisconsin Grain and Silage Relative Maturity (GRM
and SRM) rating are listed. The Wisconsin ratings are grain or silage moisture at
harvest compared to company maturity ratings. Each hybrid in a trial is rated and
averaged over all trials in a zone.
PERFORMANCE INDEX
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 multi-location 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 stalk 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:
PI = [(Yield x 0.50) + (Dry matter x 0.35) + (Upright stalks x 0.15)] / 100
SILAGE QUALITY
Corn silage quality was analyzed using near infra-red spectroscopy equations derived
from previous work of Drs. Jim Coors and Joe Lauer (UW-Madison). Plot samples were
dried, ground, and analyzed for crude protein (CP), acid detergent fiber (ADF),
neutral detergent fiber (NDF), in vitro cell wall digestibility (NDFD), in
vitro digestibility (IVD), and starch. Spectral groups and outliers were
checked using wet chemistry analysis.
MILK2000 silage performance indices, milk per ton and milk per acre, are
calculated using an adaptation by Eric Schwab and Randy Shaver (UW-Madison Dairy
Science Department) of the MILK95 model (Undersander, Howard and Shaver; Journal
Production Agriculture 6:231-235). In Milk2000, the energy content of corn
silage was estimated using a modification of a published summative energy equation
(Weiss and co-workers, 1992; Animal Feed Science Technology 39:95-110). In the modified
summative equation, CP, fat, NDF, starch, and sugar plus organic acid fractions
were included along with their corresponding total-tract digestibility coefficients
for estimating the energy content of corn silage. A regression equation developed
from literature data was used to predict total tract starch digestibility from the
samples whole-plant dry matter content. The samples lab measure of NDFD was used
for the NDF digestibility coefficient. Digestibility coefficients used for the CP,
fat, and sugar plus organic acid fractions were constants. Dry matter intake was
estimated using the samples NDF and NDFD content assuming a 1350 lb. cow consuming
a 30% NDF diet. Using National Research Council (NRC, 2000) energy requirements,
the intake of energy from corn silage was converted to expected milk per ton. Because
the cows maintenance energy requirements were partitioned against the total diet
in MILK2000 rather than against only corn silage as was done in MILK95, there
was a base increase in our new estimate of milk per ton which was of equal value
across all samples that did not influence ranking. Milk per acre was calculated
using milk per ton and dry matter yield per acre estimates.
LEAST SIGNIFICANT DIFFERENCE
Variations in yield and other characteristics occur because of variations in soil
and other growing conditions that 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 that were
not significantly lower in performance than the highest hybrid in a particular test
are indicated with an asterisk.
HOW TO USE THESE
RESULTS TO SELECT TOP-PERFORMING HYBRIDS
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 top-performing hybrids for next
year using these trial results:
- Use multi-location average data in shaded areas . Consider single location
results with extreme caution.
- Begin with trials in the zone(s) nearest you.
- 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.
- Make a list of 5 to 10 hybrids with highest 2003 Performance Index within each maturity
group within a trial.
- Evaluate consistency of performance of the hybrids on your list over years
and other zones.
- Scan 2002 results. Be wary of any hybrids on your list that had a 2002 Performance
Index of 100 or lower. Choose two or three of the remaining hybrids that have relatively
high Performance Indexes for both 2002 and 2003.
- 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 2002
or 2003 in any other zones.
- Repeat this procedure with about three maturity groups to select top-performing
hybrids with a range in maturity, to spread weather risks and harvest time.
- 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.
- You might consider including the hybrids you have chosen in your own test plot,
primarily to evaluate the way hybrids stand after maturity, dry-down rate, grain
quality, or ease of combine-shelling or picking.
- Remember that 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 next year on your farm is to consider performance in 2002
and 2003 over a wide range of locations and climatic conditions.
You are taking a tremendous gamble if you make hybrid selection decisions based on
2003 yield comparisons in only one or two local test plots.
OBTAINING DATA ELECTRONICALLY
This report is also available on the internet at
http://corn.agronomy.wisc.edu. Hybrid performance for the last 10 years
can be summarized using SELECT at the above internet address. This book can
be downloaded over the internet in Microsoft Excel
and Acrobat PDF formats
About the authors: Joe Lauer is professor of agronomy and also holds an appointment
with University of Wisconsin-Extension, Kent Kohn is senior research specialist
in agronomy, and Pat Flannery is program manager in agronomy.
This publication is available from your Wisconsin County Extension office or from
the Department of Agronomy, 1575 Linden Drive, Madison, WI 53706. Phone (608) 262-1390.
This publication can also be obtained on the web at
http://corn.agronomy.wisc.edu .
University of Wisconsin-Extension, Cooperative Extension, in cooperation with the
U.S. Department of Agriculture and Wisconsin counties, publishes this information
to further the purpose of the May 8 and June 30, 1914 Acts of Congress; and provides
equal opportunities and affirmative action in employment and programming. If you
need this material in an alternative format, contact Cooperative Extension Publications
at (608) 262-2655 or the UWEX Affirmative Action office. This publication is available
free from your Wisconsin county Extension office or from the Department of Agronomy,
1575 Linden Dr., Madison, Wisconsin 53706. Phone (608) 262-1390.
A3653 2003 Wisconsin Hybrid Corn Performance Trials - Grain and Silage.