August 2008
Field Crops 28.31-60

Corn Hybrid Selection

Joe Lauer, Corn Agronomist

PDF Version

Growing Season Update

The 2008 production year has been one of the coolest on record. Growing degree unit accumulation is tracking about 300 GDUs behind schedule. Temperature drives the vegetative (V) developmental stages of the corn life cycle, but has less influence during the reproductive (R) developmental stages (Table 1). The number of days from silking (R1) to maturity (R6) ranges from 55 to 60 days. A farmer benchmark to gauge the season is "To be dented by Labor Day."  About 26-28 days remain for the crop to mature.

Table 1. Relationship between corn kernel growth stage and development.
    Growing Degree Units
(GDUs) to Maturity
Percent of
Maximum Yield
Moisture
Content (%)

Stage

Calendar Days
to Maturity

Southern
Wisconsin

Northern
Wisconsin

Grain

Whole
Plant

Grain

Whole
Plant

R1- Silk

55-60

1100-1200

950-1050

0

50-55

---

80-85

R2 - Blister

45-50

875-975

800-900

0-10

55-60

85-95

80-85

R3 - Milk

37-42

750-850

700-800

15-25

60-65

75-85

77-82

R4 - Dough

31-36

600-700

550-650

30-50

65-75

60-80

75-80

R5 - Dent

26-28

425-525

400-500

60-75

75-85

50-55

70-75

R5.5 - 50% Kernel milk

10-15

200-300

175-275

90-95

100

35-40

65-70

R6 - Maturity

0

0

0

100

95-100

25-35

55-65

Selecting Corn Hybrids for 2009

Past hybrid trials indicate that the average yield difference between the highest and lowest yielding corn hybrid in a trial is 70 bu/A. Your challenge is to predict performance the next growing season. Depending upon how you select hybrids, yield gains up to 12 bu/A can be achieved over an "average" hybrid.

When choosing hybrids for the next growing season:

  1. Select hybrids using multi-location average data (Figure 1). Consider single location results with extreme caution.
  2. Evaluate consistency over years and other trials. Be wary of hybrids that are not top performers in all trials (Figure 1).
  3. Buy the traits you need (Tables 2, 3 and 4). Traits protect yield, they do not add to yield. Can you grow corn the "old-fashioned" way?
    • Rotation
    • Weed control
    • European Corn Borer
  4. Every hybrid must "stand on its own" for performance (Table 5). You don't know what weather conditions (rainfall, temperature) will be like next year. Therefore, the most reliable way to predict hybrid performance next year on your farm is to consider past performance over a wide range of locations and climatic conditions.

Figure 1. Next year's performance of a hybrid using various selection strategies. Simulated using UW Hybrid Trial Results 1973-1998 (L=Location, Z=Zone)

Table 2. Economic advantage ($/A) of Hybrid A or (Hybrid B). Seed price difference = $0 bag: A = $150, (B) = $150.

Table 3. Economic advantage ($/A) of Hybrid A or (Hybrid B). Seed price difference = $50 bag: A = $150, (B) = $200.

Table 4. Economic advantage ($/A) of Hybrid A or (Hybrid B). Seed price difference = $100 bag: A = $150, (B) = $250.

Table 5. Relative performance among corn hybrid "Families" compared to the normal line grown in the same trial

Family

Specialty Trait

N

Grain
yield

Grain
moisture

Lodging

   

Bu/A

%

%

A12

DDBT418

6

1

1

2

A12

MMon810

6

20

1

-3

A12

MMonGA21

25

2

0

-1

B99

MMon810

3

15

3

-2

B99

MMon810+T25

3

-2

1

-1

C284

MMon810

24

17

1

-1

C284

MMon810+IT

6

-3

0

-1


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