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Agronomic Crops Network

Ohio State University Extension


C.O.R.N. Newsletter 2012-40

Dates Covered: 
December 4, 2012 - December 18, 2012
David Dugan

Choosing Corn Hybrids for 2013

Hybrid selection is one of the most important management decisions a corn grower makes each year. It’s a decision that warrants a careful comparison of performance data. It should not be made in haste or based on limited data. Planting a marginal hybrid, or one not suitable for a particular production environment, imposes a ceiling on the yield potential of a field before it has been planted.  In the Ohio Corn Performance Test (OCPT) ( it is not unusual for hybrid entries of similar maturity to differ in yield by 80 bu/A, or more, depending on test site. Growers should choose hybrids best suited to their farm operation. Corn acreage, previous crop, soil type, tillage practices, desired harvest moisture, and pest problems determine the relative importance of such traits as drydown, insect and disease resistance, herbicide resistance, early plant vigor,  etc. End uses of corn should also be considered - is corn to be used for grain or silage? Is it to be sold directly to the elevator as shelled grain or used on the farm? Are there premiums available at nearby elevators, or from end users, for identity-preserved (IP) specialty corns such as food grade or non-GMO corn? Capacity to harvest, dry and store grain also needs consideration. The following are some tips to consider in choosing hybrids that are best suited to various production systems.

1. Select hybrids with maturity ratings appropriate for your geographic area or circumstances. Corn for grain should reach physiological maturity or "black layer" (maximum kernel dry weight) one to two weeks before the first killing frost in the fall. Grain drying can be a major cost in corn production. Use days-to-maturity, growing degree day (GDD) ratings, and harvest grain moisture data from performance trials to determine differences in hybrid maturity and drydown. In 2012 average grain moisture at most OCPT locations was well above 20% at harvest so grain moistures should be useful in assessing differences in maturity and drydown among hybrids. One of the most effective strategies for spreading risk, and widening the harvest interval, is planting multiple hybrids of varying maturity.

2. Choose hybrids that have produced consistently high yields across a number of locations. Choosing a hybrid simply because it contains the most stacked transgenic traits, or possesses appealing cosmetic traits, like “flex” ears, will not ensure high yields; instead, look for yield consistency across environments. Hybrids will perform differently based on region, soils and environmental conditions. Growers should not rely solely on one hybrid characteristic, or transgenic traits, to make their product selection. Most of the hybrids available to Ohio growers contain transgenic insect and herbicide resistance. However, the 2012 Ohio Corn Performance Tests reveal that there are some non-transgenic hybrids suitable for non-GMO grain production with yield potential comparable to the highest yielding stacked trait entries. Nevertheless, when planting fields where corn rootworm (RW) and European corn borer (ECB) are likely to be problems (in the case of RW - continuous corn, presence of the rootworm variant, and in the case of ECB - very late plantings),  Bt traits offer outstanding protection and may mitigate the impact of other stress conditions. For more on Bt traits currently available, check out the “Handy Bt Trait Table” ( from Michigan State University and the University of Wisconsin.

Given the record high temperatures and dry conditions during the 2012 growing season many farmers will be focusing on drought resistance ratings of corn hybrids. Several seed companies have introduced hybrids with enhanced drought tolerance that warrant attention. Some of these drought tolerant hybrids were evaluated in the 2012 OCPT.  When evaluating results of hybrid performance trials affected by drought, care must be taken in interpreting the results. Did a hybrid yield well under drought stress because it genuinely possesses some drought resistance or because it "escaped" the impact of high temperatures and drought by flowering before or after the worst of the stress? If it was the latter, then the hybrid's superior performance may be of limited value under different drought conditions in the future.

In past years, we have sometimes observed that if a drought occurs late in the season then early maturing hybrids will have an advantage over later maturity hybrids; if the drought occurs earlier, but is broken by rains later in the season, then the full season hybrids may have the advantage. This year yields of some short season hybrids were impacted more by stress than later maturing hybrids because they pollinated during periods of especially hot (several consecutive days with 100 degree F plus temperatures), dry conditions in late June and early July, whereas full season hybrids flowered later when conditions were less stressful.

3. Plant hybrids with good standability to minimize stalk lodging (stalk breakage below the ear). This is particularly important in areas where stalk rots are perennial problems, or where field drying is anticipated. If a grower has his own drying facilities and is prepared to harvest at relatively high moisture levels (>25%), then standability and fast drydown rates may be somewhat less critical as selection criteria. There are some hybrids that have outstanding yield potential, but may be prone to lodging problems under certain environmental conditions after they reach harvest maturity. Although stalk lodging was generally limited in 2012, some fields experienced green snap (aka “brittlesnap”) injury due to strong winds from June 30 to July 1. In the OCPT, there was considerable variability among hybrids for green snap damage. Green snap is relatively rare in Ohio. However, since green snap may result in stalk breakage near or at the base of plants, yield losses can be appreciable. Corn growers should consult with their seed dealer on hybrid sensitivity to green snap.

4. Select hybrids with resistance and/or tolerance to stalk rots, foliar diseases, and ear rots. Consult the Ohio Field Crops Diseases web page online at for the most common disease problems of corn in Ohio. In recent years, several diseases have adversely affected the corn crop - including northern corn leaf blight, gray leaf spot, Stewart’s bacterial leaf blight, and Gibberella and Diplodia ear rots. Corn growers should obtain information from their seed dealer on hybrid reactions to specific diseases that have caused problems or that have occurred locally.

5.  Never purchase a hybrid without consulting performance data. Results of state, company, and county replicated hybrid performance trials should be reviewed before purchasing hybrids. Because weather conditions are unpredictable, the most reliable way to select superior hybrids is to consider performance during the last year and the previous year over as wide a range of locations and climatic conditions as possible. Hybrids that consistently perform well across a range of environmental conditions, including different soil and weather conditions, have a much greater likelihood of performing well the next year, compared to hybrids that have exhibited more variable performance. To assess a hybrid’s yield averaged across multiple Ohio test sites consult the “Combined Regional Summary of Hybrid Performance” tables available online at


2012 Ohio Corn Performance Test: Regional Overviews

In 2012, 236 corn hybrids representing 30 commercial brands were evaluated in the Ohio Corn Performance Test (OCPT). Four tests were established in the Southwestern/West Central/Central (SW/WC/C) region and three tests were established in the Northwestern (NW) and North Central/Northeastern (NC/NE) regions (for a total of ten test sites statewide).  Hybrid entries in the regional tests were planted in either an early or a full season maturity trial. These test sites provided a range of growing conditions and production environments.

Although record high temperatures and dry conditions were widespread across Ohio during the 2012 growing season, most OCPT sites received timely rains that blunted the impact of these stress conditions. At most OCPT sites, drier and much warmer than normal conditions persisted from the early vegetative stages through early to mid grainfill. All test sites except Wooster, experienced one or more days with temperatures of 100 degrees F or more during the late vegetative stages, the pollination period and/or the early grain fill stages from late June to mid July. Greenville and Van Wert experienced a total of five days with temperatures (and four consecutive days) of 100 degrees F or more.  Greater than normal rainfall and cooler than normal temperatures in September slowed kernel maturation and delayed drydown and harvest.

At most test sites, the impact of high temperatures in July on crop performance was limited because it either preceded pollination or timely rainfall and adequate soil moisture reduced adverse effects. Yields were highest at S. Charleston and Washington CH (averaging 233 and 231 bu/A, respectively) and lowest at Beloit and Greenville (averaging 148 and 154 bu/A, respectively). Several locations, including S. Charleston, Upper Sandusky and Van Wert, experienced green snap injury and widespread root lodging due to strong winds from June 30 to July 1. There was considerable variability among hybrids for root lodging and green snap. Much of the root lodged corn recovered and showed little evidence of injury at harvest. However, green snap injury generally broke stalks off near or at the base of the plant. Averaged across the early and full season maturity tests, % green snap for hybrids evaluated at S. Charleston, Upper Sandusky and Van Wert averaged (range indicated in parentheses) 6% (0-44%), 3% (0-35%), and 1% (0-21%), respectively. Below average temperatures and persistent rains in September and October delayed crop maturation and resulted in higher than normal grain moisture at harvest at several locations. Despite the water stress present at most sites, stalk lodging was negligible – averaging no more than 7% at any location. Extensive foliar disease (northern corn leaf blight and gray leaf spot) was evident late in the season at some locations, but impact on crop performance appeared to be limited.

Tables 1 and 2 provide an overview of 2012 hybrid performance in the early maturity and full season hybrid trials by region. Averages for grain yield and other measures of agronomic performance are indicated for each region. In addition, the range in test sites averages are shown in parentheses. Complete results are available online at: and

As you review 2012 test results, it’s important to keep the following in mind. Confidence in test results increases with the number of years, and the number of locations, in which the hybrid is tested. Avoid selecting a hybrid based on data from a single test site, especially if the site was characterized by abnormal growing conditions (like drought stress and record high temperatures). Look for consistency in a hybrid's performance across a range of environmental conditions. In addition to 50% silking dates, differences in grain moisture percentages among hybrids at harvest can provide a basis for comparing hybrid maturity.  Yield, % stalk lodging, grain moisture, and other comparisons should be made between hybrids of similar maturity to determine those best adapted to your farm. Results of the crop performance trials for previous years are also available online at:   

Table 1.   A regional overview of the early maturity 2012 Ohio Corn Performance Test.





Grain Yield








Final Stand


Test Wt.













































Table 2.  A regional overview of the full season 2012 Ohio Corn Performance Test.





Grain Yield








Final Stand


Test Wt.












































2012 Forage Performance Trial Results



Results from the 2012 Ohio Forage Performance Trials are now available online at The report includes yield trials of commercial varieties of alfalfa, red and white clover, tall fescue, and annual ryegrass tests planted in 2008 to 2012 across three sites in Ohio: South Charleston, Wooster, and North Baltimore. There is also a downloadable pdf file for easy printing of the results, as well as downloadable Excel files.

Forage yields were very respectable despite the dry summer, although our testing sites received more rainfall than many areas of Ohio in 2012. Yields averaged from 5.8 to 6.5 tons/acre for alfalfa, 5.6 tons/acre for red clover, 2.4 tons/acre for white clover, 5.7 tons/acre for tall fescue, and 6.3 tons/acre for annual ryegrass (planted in September 2011).

The results demonstrate the importance of selecting adapted varieties with a proven yield record across locations. In our 2012 trials, individual alfalfa varieties varied in yield from 14 to 20% depending on location. Improved red clover varieties yielded up to 53% more than common (VNS) red clover. White clover varieties differed in yield by as much as 12.6%, tall fescue varieties differed by up to 7% yield, and annual ryegrass varieties differed by up to 42% yield.

Links to forage performance trials in other states are included on the Ohio Forage Performance Trials website. One very useful link is an interactive website to compare alfalfa varieties across many locations (including Ohio data). It is important to consider yield not only close to home, but across several environments, because every year represents different weather conditions. Varieties with good yield performance across multiple environments are likely to produce more stable yields across soil types and years on your farm.

4 R Nutrient Stewardship and Ohio Resources for Determining Fertilizer Rate

4R Nutrient Stewardship is an industry driven concept of looking at soil nutrient application. The program utilizes a science based approach to nutrient use in crop production. The program has 3 goals that match to our goals in Ohio Agriculture.

·         Increase crop production & improve profitability

·         Minimize nutrient loss & maintain soil fertility

·         Ensure sustainable agriculture for generations to come

Due to its common sense approach to define best management on the farm, this concept was quickly adapted in relation water quality concerns in Ohio’s waters, when the Directors of Ohio Environmental Protection Agency, Ohio Department of Natural Resources and Ohio Department of Agriculture met with the agricultural and environmental groups in the fall of 2011. From a farm standpoint, it considers economics of nutrient use, returns through harvested yield and incorporates practices to keep nutrients on the field for future crop production rather than leaving the field in water runoff.

The 4 R Nutrient Stewardship considers the rate of nutrients needed for the crop, then the characteristics of the nutrient source used to meet that need, as affected by the placement and timing of application. We want to use the right rate, right source, right timing and right placement in nutrient application or 4R Nutrient Stewardship.

Ohio State University Extension has several new resources that are available on our website for determination of rate of nutrients needed. These resources can be found at

Two resources can be used if you have a current soil test in hand to provide a recommendation for phosphorus and potassium. The first is a spreadsheet that will develop recommendations for up to seven fields with up to a three crop rotation. In addition to the nutrients mentioned, a lime recommendation can be generated as well. The beta version of this spreadsheet is found at  If you prefer to use a paper copy, the new factsheet Developing Phosphorus and Potassium Recommendations for Field Crops (AGF-515-12) is available that walks you through using the printed tables from the publication Tri-State Fertilizer Recommendations for Corn, Soybeans, Wheat and Alfalfa E-2567.

If looking at soil test reports is new to you, or you are out of practice, the factsheet Interpreting a Soil Test Report (AGF-514-12) points out key parameters to look at on the report. It is available at . This factsheet walks you through a soil test report describing desirable ranges and what the numbers mean on your report.

A current soil test is the foundation to develop a fertility program. If you do not have a current soil test (taken in the past three years) a good place to start is with a new soil test. The factsheet Soil Sampling to Develop Nutrient Recommendations (AGF 513-12) is available at .  This factsheet discusses how to look at a field to get a representative sample, guidelines to taking a sample and sending a sample to the lab. Traditional as well zone and grid sampling schemes are covered. If you are looking for a laboratory to send your collected samples to there is a reference for soil testing labs in and around Ohio at


CCA Exam Prep Course

Those of you who work with recommendations for crop input practices and products are reminded that the next Certified Crop Adviser (CCA) exam is coming soon.

Next ICCA Exam Date: February 01, 2013

Registration Period for the exam: ends December 07, 2012

Registration is available on-line at

Register for both the local/regional (IL, IN & OH exam) and the international exams. The Ohio testing location is the Ohio Department of Agriculture in Reynoldsburg. The local exam cost is $50 and the cost of the International Exam Fee is $175. Then August 2nd will be the summer CCA Exam, and registration will open six weeks before that date.

An exam preparation course will be offered in Sidney, Ohio on January 16 and 17, 2013. The Ohio CCA Exam Preparation Course will be held in the Shelby County Extension office in Sidney Ohio. The cost is $225. The link includes information and registration materials related to the course. Registration is due by January 9th.

Ohio experts who provide training are all CCAs, including Robert Mullen, Bruce Clevenger, Greg LaBarge and Harold Watters.


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Crop Observation and Recommendation Network

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.