December, 1998
A3653

1998 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

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 available to Wisconsin corn growers. These trials evaluate corn hybrids for both grain and silage production performance.

TESTING PROCEDURE

In 1998, grain and silage performance trials were planted at thirteen locations in four production zones. Both seed companies and university researchers submitted hybrids (see hybrid index). Companies with hybrids included in the 1998 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.

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

Seasonal precipitation and temperature at the 1998 sites are shown in Table 2. Both grain and silage yields were above normal, especially in the southern half of Wisconsin. Northern Wisconsin had below average precipitation. Planting conditions were good during the spring of 1998. Corn planting progress was 20 percent ahead of the five-year average. Growing degree unit accumulation was above normal throughout the entire growing season. Fall growing conditions were drier than normal. A killing frost did not occur until mid-October. During the fall harvest season, yields were generally good to excellent, and moisture was low decreasing drying costs and offsetting low corn prices somewhat for many farmers.

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

Plots were planted with a corn planter except for trials at Ashland in the Northern Zone, which were hand-planted. Two-row plots were planted at all locations except Ashland, where one-row plots were used. Twenty-two 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 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.

Silage
Whole-plant (silage) plots were harvested using a tractor driven, three-point mounted one-row chopper. At Ashland, plots were hand-harvested. 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.

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 1998 locations conducted in that zone. Yield and moisture data for both 1997 and 1998 are provided if the hybrid was entered previously in the 1997 trials.

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 that 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, Agriculture Extension Service, University 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.

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:

(Yield % x 50) + (Dry matter % x 35) + (upright stalks % x 15)
100

SILAGE QUALITY

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), cell wall digestibility (CWD), 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).

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:

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 1998 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.
   1. Scan 1997 results. Be wary of any hybrids on your list that had a 1997 Performance Index of 100 or lower. Choose two or three of the remaining hybrids that have relatively high Performance Indexes for both 1997 and 1998.
   2. 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).
   3. Be wary of any hybrids with a Performance Index of 100 or lower for 1997 or 1998 in any other zones.
6. 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.
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, dry-down rate, grain quality, or ease of combine-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 1997 and 1998 over a wide range of locations and climatic conditions.

You are taking a tremendous gamble if you make hybrid selection decisions based on 1998 yield comparisons in only one or two local test plots.

OBTAINING DATA ELECTRONICALLY

The information in 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 98 that can be downloaded from the above internet address. This book can be downloaded from the internet in a Microsoft Excel 97 format.

About the authors: Joe Lauer is associate professor of agronomy and also holds an appointment with University of Wisconsin-Extension, Kent Kohn is research specialist in agronomy, and Pat Flannery is senior research specialist in agronomy.

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 1998 Wisconsin Hybrid Corn Performance Trials - Grain and Silage.