About the 2005 Test

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2005 KENTUCKY HYBRID CORN PERFORMANCE TEST

William L. Pearce, Ron W. Curd and Dr. Chad Lee.

The objective of the Kentucky Hybrid Corn Performance Test is to provide performance estimates of hybrid seed corn sold in Kentucky. Every effort has been made to conduct the test in an unbiased manner according to accepted agronomic practices.

PRESENTATION OF DATA

Complete 2005 data is presented for the tests at each location. Two-and three-year averages for yield are included in each of the single location tables. Readers are encouraged to consider multiple year averages and averages over locations reported in Tables 4E-1YR, 4E-2YR 4E-3YR, 5M-1YR, 5M-2YR, 5M-3YR, 6L-1YR, 6L-2YR, 6L-3YR, 7W-1YR, 7W-2YR and 7W-3YR. These tables present better estimates of hybrid yield ability than data gathered at one location in one year.

Comparisons between yields and other characters of any two or more hybrids should be made only with data from one table at a time. Hybrids are grouped into Early, Medium, Late, White, and High Oil tests based on relative maturity or trait characteristic.  Hybrids that yield equally as high as the highest yielding hybrid, based on statistical evaluation, are indicated by an asterisk. See the HYBRID COMPARISONS and the EXPERIMENTAL DESIGN AND MEANS COMPARISONS text sections for more detail.

TESTING PROCEDURE

SELECTION OF HYBRIDS

The hybrids chosen for testing are those most likely to be available for sale in 2006. Seed of each commercial hybrid (Table 2) was obtained from the sponsoring company. Each company defined the maturity of their hybrids and was given the opportunity to identify the proper tests for their hybrids.

LOCATION OF TESTS

The map on page 1 shows the test locations. The test sites were selected to represent different agroclimatic areas of Kentucky where corn is a major commodity.

CULTURAL PRACTICES

Corn was planted no-till into soybean stubble at all locations, except for Quicksand where corn was planted no-till into wheat cover crop stubble.  Fertilizer was applied as indicated by soil tests.

All test areas were treated with herbicide(s), insecticide(s) and supplemented by postemergence herbicide when necessary. Force was applied in the row at planting to control corn rootworms. Table 3 shows the specific cultural treatment for each location and includes notes about the growing season.

EXPERIMENTAL DESIGN AND MEAN COMPARISONS

Each hybrid was grown in three replications at each location to sample uncontrollable variability within the field. Annual mean yields presented in the tables are averages of three replications at the test site, while 2-year and 3-year means are averages of six and nine replications, respectively. A randomized complete block (RCB) design was used for each maturity group test at each location.

These tests are designed to predict yield ability. Slight differences in yield ability can occur as a result of variability in the field. The least significant difference (LSD) is used to account for that variability and to help determine significant differences between hybrid performances.

Consider the following example:

The yield difference between Hybrid A and Hybrid B is 10 bu/acre (165 – 155 = 10). The difference is less than the LSD (12 bu/acre). Based on the LSD, the yield difference between hybrids A and B is not significant. Hybrids A and B have the same yield in this test. However the yield difference between hybrids A and C is 25 bu/acre (165 - 140 = 25) which is greater than the LSD (12 bu/acre).  Based on the LSD, Hybrid A yielded more than Hybrid C in this test.

The LSD occurs at the bottom of each table. Yields that are less than the LSD are not significantly different from each other. The notation "N.S." in the tables indicates that no statistically significant differences were determined. An asterisk has been placed alongside yields that are not significantly different from the highest yield mean in that column. In addition, the tables are sorted from greatest yield to least yield.

The C.V. is a calculated value that helps indicate unexplained variation.  A smaller C.V. indicates less unexplained variation and more precise results.

PLANTING

All plots were planted with a John Deere Maxi-Emerge vacuum, two-row, no-till planter modified for small plot work. Modified planting cones replaced the planter boxes and  allowed placement of a specified number of kernels per plot. Each hybrid seed was planted into plots consisting of two rows 30 inches apart and 22 feet long. Hybrid seed was planted at 40 seeds/row for each plot. When seedlings were 12 to 18 inches tall, the stands were thinned to 33 plants/row equaling 26,000 plants/acre.

HARVESTING

All plots were harvested with a Massey Ferguson MF 8-XP two-row corn combine. Both rows of each two-row plot were picked and shelled. The grain weight, moisture content, and test weight of corn from each plot was measured with an electronic scale and moisture meter mounted on the combine. Yields were calculated for grain at 56 pounds per bushel and adjusted to 15.5% moisture. The test weight reported in each annual table for any hybrid is not corrected for harvest moisture and is reported at the moisture content for that hybrid listed in that table. Dropped ears were not gleaned from the plots.

The total number of lodged plants was recorded at harvest. Also at harvest, selected plots were observed to indicate apparent European corn borer damage by counting the number of broken tops per plot, according to a protocol by Dr. Rick Bessin, Department of Entomology, University of Kentucky. Corn borer damage was minor at all locations. In general, Bt hybrids had less apparent corn borer damage than non-Bt hybrids.

HYBRID COMPARISONS

The Kentucky Hybrid Corn Performance Test is divided into five tests: Early, Medium and Late maturities, White, and High Oil hybrids. These divisions provide evaluations of the five hybrid groups without competition biases. The divisions do not allow for comparisons across groups. For example, a hybrid in the Early test cannot be compared to a hybrid in the Late test. The Early, Medium, Late and White tests were grown at all seven locations for a total of 28 tests. The High Oil tests were grown at two locations.

The Early maturity hybrid group in Table 4E, and all subsequent "E" tables, are those hybrids rated by the parent seed company to mature in 112 days or earlier.

The Medium maturity hybrid group in Table 4M, and all subsequent "M" tables includes those hybrids rated by the parent seed company to mature in 113-117 days.

The Late maturity hybrid group in Table 4L and all subsequent "L" tables include those hybrids rated by the parent seed company to mature in 118 days or later.

The White hybrid group in Table 4W and all subsequent ”W” Tables includes those hybrids with a white seed coat and rated by the parent seed company to mature in 112 to 118 days.

The High Oil hybrid group in Table 16 includes those hybrids with the TopCross Blend trait.

Open-pedigree hybrids of known maturity were included in each Early, Medium, and Late test, to provide an internal evaluation of hybrid maturity. The seed of these hybrids was obtained from Illinois Foundation Seeds, Inc., at Champaign, IL.

Grain moisture of hybrids in the Early, Medium, and Late tests should be within the LSD of the check hybrid grain moisture for that test. Hybrids with grain moisture above the LSD of the check hybrid likely belong in a later-maturing test. Each hybrid is placed in the Early, Medium, and Late tests based on the hybrid maturity defined by the company.

Notes about the 2005 growing season follow Table 3.

CHEMICAL ANALYSIS OF THE EARLY, MEDIUM, LATE, AND WHITE TESTS

Grain chemical composition was measured from one replication of each Early, Medium, Late and White maturity test at each location. These samples were analyzed by the Kentucky Grain Quality Laboratory at Lexington¹ using NIRS. The NIRS analysis provided evaluation of protein, starch, and oil and is presented in Tables 8 and 16 for grain at 0% moisture.

Since grain used in feed rations contains moisture, the composition variables provided in Table 8 and 16 should possibly be used at a moisture content that is different than 0%. A suitable moisture in most feed rations is 15%. To covert to 15% moisture, multiply the values in Tables 8 or 16 by 0.85. For any other moisture content, multiply the values by (100-%moisture)/100.

HIGH OIL TESTS

Six high oil hybrid blends (TC High Oil Blend®) were tested at two locations with three replications per location. The two location average yield data is available in Table 16D. A 20 to 25 plant hand pollinated sample from each replication of the Lexington test was analyzed for chemical composition. The chemical composition values presented in Table 16F are given for grain at 0% moisture.

ACKNOWLEDGEMENTS

The authors sincerely appreciate efforts of the Kentucky Corn Growers Association in helping upgrade equipment. A Massey Ferguson MF 8-XP combine was leased to the corn project at minimal cost by the Kentucky Corn Promotion Council of the Kentucky Corn Growers Association. This combine contributed to improved accuracy of the data.

The authors are grateful to Dr. Michael Montross, Wei Chen (Research Analyst) and the Kentucky Corn Growers Association for the Grain Quality Laboratory, which processed more than 1000 grain samples. The authors are grateful to the following farmer-cooperators who not only provided land for testing but helped with the tests throughout the growing season: Dennis and David Joseph and family of Benton, Dale Tucker and family of Bowling  Green, Steve Sheffer and family of Hodgenville and Tim Thomas and family of Waverly, KY.

The authors - acknowledge the statistical and programming support of Dr. Paul L. Cornelius and Mr. Danny Walls of the Agronomy Department.

Additional acknowledgements are made to the following people who helped conduct this year's performance test.

Richard C. Green, Research Technician, Dept. of Agronomy, Lexington, KY

Dr. James Herbek, Extension Specialist in Grain Crops, Research and Extension Center, Princeton, KY

Donnie Davis, Superintendent, and Joe Williams, Farm Manager. Research and Education Center, Princeton, KY

David Ditsch Superintendent, and Wade Turner, Farm Manager, Robinson Substation, Quicksand, KY

Dennis Duross, Communication Specialist, Agricultural Communications, Lexington, KY.

Lincoln Martin, Extension Agent, Marshall County, KY

Joanna Coles, Extension Agent, Warren County, KY

Rankin Powell, Extension Agent, Union County, KY

David Harrison, Extension Agent, LaRue County, KY

¹ The Grain Quality Laboratory is a service provided by the University of Kentucky with funding from the Kentucky Corn Growers Association.

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TABLE 2. HYBRIDS TESTED IN 2005

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