2008 WISCONSIN CORN HYBRID PERFORMANCE TRIALS
GRAIN AND SILAGE
Joe Lauer, Kent Kohn, and Thierno Diallo
The University of Wisconsin Extension-Madison and College of Agricultural and Life
Sciences conduct a 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.
In 2008, grain and silage performance trials were planted at fourteen locations
in four production zones. Both seed companies and university researchers submitted
hybrids. Companies with hybrids included in the 2008 trials are listed in
Table 1. Specific hybrids and where they were tested are shown in
Table 2. In the back of the report, hybrids previously tested over the
past three years are listed (Table 27). 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.
GROWING CONDITIONS FOR 2008
Seasonal precipitation and temperature at the trial sites are shown in
Table 4. Spring planting was delayed due to cool and wet planting conditions.
Plant stands in the trials were excellent. Above normal precipitation occurred during
June leading to some flood damage in southern Wisconsin. During August and September,
drought stress was evident on corn plants in northwestern Wisconsin affecting hybrid
performance at Chippewa Falls and Spooner. For southern Wisconsin, accumulation
of growing degree units for the entire season was below average. Plant development
variability within a field was often high. Little insect or disease pressure was
observed in most trials. Standability was excellent, except after a wide-spread
storm with rain and high winds that occurred in late October affecting some trials
that hadn't been harvested yet. A killing frost occurred in late-October. Harvest
grain moisture was higher than normal in southern late maturity trials. Yields in
the UW hybrid trials were average to above average at most sites. Plots at the Rhinelander
location were not harvested due to poor emergence.
The seedbed at each location was prepared by either conventional or conservation
tillage methods. Seed treatments of hybrids entered into the trials are described
in Table 3. Fertilizer was applied as recommended 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 5.
A precision vacuum corn planter was used at all locations, except Spooner. Two-row
plots, twenty-five foot long, were planted at all locations. Plot were not hand-thinned.
Each hybrid was grown in at least three separate plots (replicates) at each location
to account for field variability.
Grain: Two-row plots were harvested with a selfâ€‘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. Test weight
was measured on each plot.
Silage: Wholeâ€‘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. 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
Wisconsin Relative Maturity Belts and test sites.
Arlington, East Troy, Janesville, Lancaster
Early Maturity Trial: 105â€‘day or earlier
Late Maturity Trial: later than 105â€‘day
South Central Zone
Fond du Lac , Galesville, Hancock (irrigated)
Early Maturity Trial: 100â€‘day or earlier
Late Maturity Trial: later than 100â€‘day
North Central Zone
Chippewa Falls , Marshfield , Seymour , Valders
Early Maturity Trial: 90â€‘day or earlier
Late Maturity Trial: later than 90â€‘day
Spooner (three sites), Marshfield
Arlington and Lancaster
Early Maturity Trial: 109â€‘day or earlier
Late Maturity Trial: later than 110â€‘day
South Central Zone
Fond du Lac and Galesville
Early Maturity Trial: 104-day or earlier
Late Maturity Trial: later than 104-day
North Central Zone
Chippewa Falls, Marshfield, Valders
Early Maturity Trial: 99â€‘day or earlier
Late Maturity Trial: later than 99â€‘day
Spooner (two sites), Marshfield
Arlington, East Troy, Janesville, Lancaster
Corn Rootworm Trial
Roundup Ready Trial
South Central Zone
Fond du Lac, Galesville, Hancock (dryland)
Corn Rootworm Trial
Roundup Ready Trial
PRESENTATION OF DATA
Yield results for individual location trials and for multiâ€‘location averages are
listed in Tables 6 through 26. Within each trial, hybrids are ranked by moisture,
averaged over all trials conducted in that zone during 2008. Yield data for both
2007 and 2008 are provided if the hybrid was entered previously in the 2007 trials.
A two-year average for yield is calculated using location means as replications.
In the Corn Rootworm and Roundup Ready specialty trials, a multi-location average
is calculated using trial means within a production zone as replications. In the
specialty Dryland trial at Hancock, an average was calculated using data from both
the dryland and irrigated trials using trial as replications. A hybrid index (Table 2) lists relative maturity ratings, specialty
traits, seed treatments and production zones tested for each hybrid.
Seed companies use different methods and standards to classify or rate the maturity
of corn hybrids. To provide corn producers a â€œstandardâ€ maturity comparison for
the hybrids evaluated, the average grain or silage moisture of all hybrids rated
by the company relative maturity rating system are shown in each table as shaded
rows. In these Wisconsin results tables, 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. Company relative maturity ratings are rounded
to 5-day increments.
The Wisconsin Relative Maturity rating system for grain and silage (GRM and SRM)
compares harvest moisture of a grain or silage hybrid to the average moisture of
company ratings using linear regression. Each hybrid is rated within the trial and
averaged over all trials in a zone. Maturity ratings (Company, GRM and SRM) can
be found in Table 2.
GRAIN PERFORMANCE INDEX
Three factorsâ€”yield, moisture, and standabilityâ€”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 multiâ€‘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:
Performance Index (P.I.) = [(Yield x 0.50) + (Dry matter x 0.35) + (Upright
stalks x 0.15)] / 100
SILAGE PERFORMANCE INDEX
Corn silage quality was analyzed using near infra-red spectroscopy equations derived
from previous work. 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.
The MILK2006 silage performance indices, milk per ton and milk per acre,
were calculated using an adaptation by Randy Shaver (UW-Madison Dairy Science Department)
of the MILK91 model (Undersander, Howard and Shaver; Journal Production Agriculture
6:231-235). In MILK2006, 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. Whole-plant dry matter content was normalized to
35% for all hybrids. The sample 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 NDF and NDFD
content assuming a 1350 lb. cow consuming a 30% NDF diet. Using National Research
Council (NRC, 2001) energy requirements, the intake of energy from corn silage was
converted to expected milk per ton. 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 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 TOPâ€‘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 topâ€‘performing hybrids for next
year using these trial results:
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 moistureâ€”within about 2% range in moisture.
4. Make a list of 5 to 10 hybrids with highest 2008 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.
a. Scan 2007 results. Be wary of any hybrids on your list that had
a 2007 Performance Index of 100 or lower. Choose two or three of the remaining hybrids
that have relatively high Performance Indexes for both 2007 and 2008.
b. 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 6 and 7,
are also entered in the South Central Zone Trials, Tables 8 and 9).
c. Be wary of any hybrids with a Performance Index of 100 or lower
for 2007 or 2008 in any other zones.
6. Repeat this procedure with about three maturity groups to select topâ€‘performing
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, dryâ€‘down rate,
grain quality, or ease of combineâ€‘shelling or picking.
9. 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 2007 and 2008 over a wide range of locations and climatic conditions.
You are taking a tremendous gamble if you make hybrid selection decisions based on
2008 yield comparisons in only one or two local test plots.
OBTAINING DATA ELECTRONICALLY
This report is 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 a professor of agronomy and also holds an
appointment with University of Wisconsin-Extension. Kent Kohn is the corn program
manager in agronomy and Thierno Diallo is an assistant research specialist 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.
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.
References to transgenic traits in this publication are for your convenience
and are not an endorsement or criticism of one trait over other similar traits.
Every attempt was made to ensure accuracy of traits in the hybrids tested. You are
responsible for using traits according to the current label directions of seed companies.
Follow directions exactly to protect the environment and people from misuse. Failure
to do so violates the law.
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 2008 Wisconsin Hybrid Corn Performance Trials - Grain and Silage.