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Using Corn Hybrid Yield Data to Improve Selection of Rapidly Changing Hybrids

Robert Klein1, Lenis A. Nelson2 and Roger W. Elmore2

1 University of Nebraska West Central Research and Extension Center, North Platte, NE 69101 Email rklein1@unl.edu
2
University of Nebraska Department of Agronomy and Horticulture, Lincoln, NE 68583

Abstract

Choosing the proper hybrid can greatly enhance crop production profitability. This paper illustrates how to use corn hybrid test data and adjust it to your farm when selecting seed. How often should you change hybrids? An Auburn University study compared the top corn hybrids from a 3-year regional trial (7156 kg/ha average) with the top hybrids from the previous year's test (7470 kg/ha average). Since the yields went from 7156 to 7470 kg/ha - a 314 kg/ha increase - using data from 11 locations and 8 years, should we expect twice that difference - a 628 kg/ha increase - with yields of 14311 kg/ha? If so, one might conclude that to maximize corn yield, hybrids must be constantly replaced. Plant breeders are certain that genotype response is different in different environments. Grain producers need to be aware of that response to select the best hybrids for their farm. There are year-to-year differences also. The cost of seed of the best yielding hybrid and a lesser yielding hybrid often are nearly equal so the benefits derived from spending the time to choose the correct hybrid are pure profit.

Media summary

Right or wrong decisions in corn hybrid selection can enhance or negate all other factors. How we use and adjust yield data is the key factor to selection.

Key Words

Hybrid selection, yield, corn

Introduction

Most producers plant more than one hybrid on their farm. This strategy offers many benefits. The first is from having genetic diversity. This increases the possibility of having the best hybrid for a given year. One method of obtaining diversity is to select hybrids from the top yielding group that differ in harvest moisture or other traits. Another advantage of growing several hybrids is that maturity dates can be spread. Growing hybrids with varying disease and insect resistance will help spread the risk and workload.

Data on corn hybrids are available from many sources. The University of Nebraska Corn Hybrid Tests report (EC-105) is a good starting place for choosing a new hybrid. This publication is updated annually and is available at local county Extension offices and on the World Wide Web at http://varietytest.unl.edu. This publication allows for fair comparisons of entries from many companies. Information presented includes yield, moisture, bushel weight, disease reaction when differences were noted, and other characteristics when available. These data are summarized over multiple locations and years. After identifying some superior hybrids from these tests, consult literature or representatives from those companies marketing them about their strengths and weaknesses. Once a new hybrid is chosen, we suggest that it be limited to less than 20 percent of your acres the first year. Acreages can be increased the second year if performance warrants it.

A number of characteristics have been mentioned regarding hybrid selection. Generally, yield is the first factor considered in choosing a new hybrid, followed closely by maturity. With corn, maturity will influence planting date and determine harvest date, harvest moisture, and the chances of getting caught with immature corn in case of an early frost. Other factors to consider are disease resistance, insect resistance, herbicide resistance, quality, and seed price.

Methods

Let's first examine the latest copy of the Nebraska Corn Hybrid Test EC-105. It includes: plot locations, problems, farmer entries, cooperators, soil types, planting and harvest dates, average performance at each location and maps of test sites. Also included are brands, seed companies and addresses.

Locate the tests in your area. For the purpose of illustration we will say you farm in south central Nebraska and the tests at Clay and Harlan counties best apply. See Table I. First look at the column with the average yields of the two locations. We list only the top 24 out of 64 entries in the test. Look at the difference required for significance (LSD), which in this test is less than or equal to 1004 kg/ha (see next to last row). The Least Significant Difference (LSD) is listed at the 0.05 level. These values indicate how large a difference is needed to be confident that one variety is superior to another. Differences between varieties that are equal to or greater than the 0.05 LSD have only a 1 in 20 chance of being due to chance or error. By subtracting 1004 kg/ha from the top yielding hybrid (14813 kg/ha), we get 13809 kg/ha. Highlight those hybrids with a yield from 13809 to 14813 kg/ha. This is the high yielding group of hybrids. If possible, select hybrids from this group.

Our next step is to highlight the top yielding hybrids in both Clay and Harlan counties. For Clay, since the LSD is 1193, we subtract 1193 from the top yield, which is Kruger K-9114 BT at 16320 kg/ha. Highlight all those hybrids yielding from 15127 to 16320 kg/ha. In Harlan County, we highlight those within 1444 kg/ha of the highest yielding hybrid (13320 kg/ha) 13370 – 1444 = 11926 kg/ha. See Table II. All of the highlighted hybrids within a column are not significantly different from the highest yielding hybrid given the variability inherent in our trials.

The next step is to assure that there is some diversity in the top-yielding hybrids. One method to assure this when selecting hybrids that yield comparably is to examine other hybrid characteristics such as moisture. To highlight the various moisture groupings start with the lowest moisture since that is preferred and work up. The LSD is 0.9 percent for moisture. Our lowest moisture is 17.1. The moisture groupings in Table II, as indicated by the following colors, are: 1) 17.1 - 18.0 - Green; 2) 18.1 - 19.0 - Yellow; and 3) 19.1 - 20.0 - Pink.

Table II has been highlighted to show the moisture groupings. Of the high yielding group, two hybrids were in the lowest grain moisture group (green). To ensure genetic diversity we would only grow one of these two since they yielded the same and had the same moisture content. Likewise, 18 of the top yielding hybrids were in the middle (yellow) moisture group. Again, we recommend growing only one of these to help ensure genetic diversity. Continue using this logic until you have two to three new hybrids to grow next year. By selecting hybrids out of the various groups we can increase the probability of the hybrids being genetically different. Use information from seed comparisons on corn grower plots to supplement this process.

The next step is to examine last year's yields. As an example Table III includes data for a hypothetical farm. Examine the hybrid test publication to see if any of the hybrids on "your farm" (Table III) were included in the tests. Two are highlighted in Table IV. We add the yields, moisture, broken stalks, and dropped ears from the NU test results in the adjusted columns.

To compare "your corn" yields and the yields in the NU tests we need to adjust the yield on "your farm". This is done in Table V. For example, the yield in the NU test was 1318 kg/ha higher for Hawkeye and 1193 kg/ha higher for Kruger or 1255 kg/ha higher on the average. Therefore, we will increase yields for your other hybrids by 1255 kg/ha to compare them. See Table VI.

We will also make adjustments for moisture, broken stalks, and dropped ears in the same way (Tables V and VI). You are now ready to make your selection for next year. Compare your information directly to the yield trial information using the adjusted values. Remember to select hybrids with different characteristics to assure greater diversity. In this example, you might select BobsWonder and Hawkeye. These are the two hybrids with the highest adjusted yields and there is a large difference in their adjusted moisture values. Record your hybrid selections in Table VII.

Tables

Table I. South Central Irrigated Corn Hybrid Tests, Clay and Harlan Counties in 2002.

Brand

Hybrid

Yield

Grain
Moisture
%

Broken
Stalk
%

Dropped
Ear
%

Average
Kg/ha

Clay Co
Kg/ha

Harlan Co
Kg/ha

HAWKEYE

SX70

14813

16194

13370

18.5

0

0

KAYSTAR

KX-890Bt

14751

16194

13244

18.1

0

0

FONTANELLE

5282

14562

15881

13181

18.7

0

0

KRUGER

K-9114 Bt

14500

16320

12617

18.8

0

0

PIONEER

33P67*

14437

16132

12742

19.5

1

0

PFISTER

2656

14374

15692

13056

18.0

0

0

KAYSTAR

KX-898

14374

15692

12993

18.2

1

0

PFISTER

2750

14311

15755

12805

18.6

1

1

DEN BESTEN

2212

14249

15881

12617

18.6

0

1

KRUGER

K-9114

14186

15316

12993

18.1

0

0

ASGROW

RX889

14123

15755

12428

19.7

1

0

HAWKEYE

314Bt

14123

15253

12930

18.9

0

0

RENZE

6363

14060

15629

12428

18.3

0

0

KRUGER

K-9313

13872

14939

12742

19.1

1

0

KRUGER

K-9315 Bt

13872

15755

11926

19.0

1

0

KRUGER

K-9217Bt

13872

14939

12742

18.6

1

0

LG SEEDS

LG 2606

13872

15441

12303

18.3

0

0

BO-JAC

5548

13809

15065

12554

18.8

2

0

KRUGER

K-9315B BT

13809

15504

12114

17.5

1

0

M/W GENETICS

G 8122

13809

15692

11926

19.1

1

0

OTTILIE

5333

13809

15692

11926

18.1

1

0

PFISTER

2730

13809

14688

12930

18.8

0

0

OTTILIE

5250

13746

16006

11487

18.3

1

0

RENZE

8492Bt

13746

15378

12114

18.8

0

1

Avg All Entries

 

13433

14939

12052

18.7

1

0

Dif Req. for Sig 5%

 

1004

1193

1444

0.9

NS

NS

*Entered by UNL

Top Grouping

14813-13809

         

Table II. South Central Irrigated Corn Hybrid Tests, Clay and Harlan Counties in 2002.

Brand

Hybrid

Yield

Grain
Moisture
%

Broken
Stalk
%

Dropped
Ear
%

Average
Kg/ha

Clay Co.
Kg/ha

Harlan Co.
Kg/ha

HAWKEYE

SX70

14813

16194

13370

18.5

0

0

KAYSTAR

KX-890Bt

14751

16194

13244

18.1

0

0

FONTANELLE

5282

14562

15881

13181

18.7

0

0

KRUGER

K-9114Bt

14500

16320

12617

18.8

0

0

PIONEER

33P67*

14437

16132

12742

19.5

1

0

PFISTER

2656

14374

15692

13056

18.0

0

0

KAYSTAR

KX-898

14374

15692

12993

18.2

1

0

PFISTER

2750

14311

15755

12805

18.6

1

1

DEN BESTEN

2212

14249

15881

12617

18.6

0

1

KRUGER

K-9114

14186

15316

12993

18.1

0

0

ASGROW

RX889

14123

15755

12428

19.7

1

0

HAWKEYE

314Bt

14123

15253

12930

18.9

0

0

RENZE

6363

14060

15629

12428

18.3

0

0

KRUGER

K-9313

13872

14939

12742

19.1

1

0

KRUGER

K-9315Bt

13872

15755

11926

19.0

1

0

KRUGER

K-9217Bt

13872

14939

12742

18.6

1

0

LG SEEDS

LG2606

13872

15441

12303

18.3

0

0

BO-JAC

5548

13809

15065

12554

18.8

2

0

KRUGER

K-9315BBT

13809

15504

12114

17.5

1

0

M/W GENETICS

G8122

13809

15692

11926

19.1

1

0

OTTILIE

5333

13809

15692

11926

18.1

1

0

PFISTER

2730

13809

14688

12930

18.8

0

0

OTTILIE

5250

13746

16006

11487

18.3

1

0

RENZE

8492Bt

13746

15378

12114

18.8

0

1

Avg All Entries

 

13433

14939

12052

18.7

1

0

Dif Req. for Sig 5%

 

1004

1193

1444

0.9

NS

NS

*Entered by UNL

TopGrouping

14813-13809

16320-15253

13370-11926

     

Table III. 2002 Corn Yields - Your Farm, NE.

Brand

Hybrid

Hectares

Yield
Kg/ha

Adj.
Yield

Moisture

Adj.
Moisture

Broken
Stalks
%

Adj.
Broken
Stalks

Dropped
Ears

Adj.
Dropped
Ears

LensSuperX

2999

162

10985

 

21.5

 

0

 

0

 

BobsWonder

5880

101

14437

 

15.6

 

2

 

2

 

Hawkeye

SX70

101

13495

 

20.0

 

1

 

1

 

Winners

8970

20

13495

 

15.0

 

1

 

6

 

Kruger

K9313

20

12679

 

20.7

 

2

 

1

 

Table IV. Common Hybrids Grown on Your Farm and in UNL Trials in 2002.

Brand

Hybrid

Hectares

Yield
Kg/ha

Adj.
Yield

Moisture

Adj.
Moisture

Broken
Stalks
%

Adj.
Broken
Stalks

Dropped
Ears

Adj.
Dropped
Ears

LensSuperX

2999

162

10985

 

21.5

 

0

 

0

 

BobsWonder

5880

101

14437

 

15.6

 

2

 

2

 

Hawkeye

SX70

101

13495

14813

20.0

18.5

1

0

1

0

Winners

8970

20

13495

 

15.0

 

1

 

6

 

Kruger

K9313

20

12679

13872

20.7

19.1

2

1

1

0

Table V. 2002 Corn Yields - Your Farm, NE Adjustments for Yield and Other Characteristics.

Brand

Hybrid

Hectares

Yield
Kg/ha

Adj.
Yield

Moisture

Adj.
Moisture

Broken
Stalks
%

Adj.
Broken
Stalks

Dropped
Ears

Adj.
Dropped
Ears

LensSuperX

2999

162

10985

 

21.5

 

0

 

0

 

BobsWonder

5880

101

14437

 

15.6

 

2

 

2

 

Hawkeye

SX70

101

13495

14813

20.0

18.5

1

0

1

0

     

+1318

 

-1.5

 

-1

 

-1

 

Winners

8970

20

13495

 

15.0

 

1

 

6

 

Kruger

K9313

20

12679

13872

20.7

19.1

2

1

1

0

     

+1193

 

-1.6

 

-1

 

-1

 
       

+1255

 

-1.5

 

-1

 

-1

Table VI. 2002 Corn Yields - Your Farm, NE.

Brand

Hybrid

Hectares

Yield
Kg/ha

Adj.
Yield

Moisture

Adj.
Moisture

Broken
Stalks
%

Adj.
Broken
Stalks

Dropped
Ears

Adj.
Dropped
Ears

LensSuperX

2999

162

10985

12240

21.5

20.0

0

0

0

0

BobsWonder

5880

101

14437

15692

15.6

14.1

2

1

2

1

Hawkeye

SX70

101

13495

14813

20.0

18.5

1

0

1

0

     

+1318

             

Winners

8970

20

13495

14750

15.0

13.5

1

0

6

5

Kruger

K9313

20

12679

13872

20.7

19.1

2

1

1

0

     

+1193

             
       

+1255

 

-1.5

 

-1

 

-1

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