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) (http://www.oardc.ohio-state.edu/corntrials/) it is not unusual for hybrid entries of similar maturity to differ in yield by 50 bu/A or more, depending on test site. Another consideration in hybrid selection which has received more attention recently as commodity prices have dropped are seed costs which increased an average of 11% per year from 2006 and 2014, much higher than the rates for fertilizers and pesticides (http://farmdocdaily.illinois.edu/2017/07/seed-costs-for-corn-in-2017-and-2018.html). Since 2014, per acre seed costs have decreased slightly (USDA Economic Research Service), from $102 per acre in 2015 to $99 per acre in 2016, a decrease of $3 per acre.
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. 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. In the 2017 OCPT over 90% of the hybrids tested contained transgenic traits. However, recent OCPTs reveal that some non-transgenic hybrid entries have yield potential comparable to the highest yielding stacked trait entries. Nevertheless, when planting fields where corn rootworm (RW), European corn borer (ECB) and Western Bean Cutworm (WBC) are likely to be problems (in the case of RW - continuous corn and in the case of ECB and WBC - 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 most recent version of the “Handy Bt Trait Table” from Michigan State University (http://www.msuent.com/assets/pdf/BtTraitTable15March2017.pdf).
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. There are hybrids that have outstanding yield potential, but may be more susceptible to lodging problems under certain environmental conditions after they reach harvest maturity. The potential for stalk lodging increases at higher plant populations (usually above 32,000 -33,000 plants per acre) but many hybrids can tolerate higher final stands. Corn growers should consult with their seed dealer on hybrid sensitivity to stalk lodging, root lodging and greensnap (pre-tassel stalk brakeage caused by wind). Greensnap is relatively rare in Ohio but may cause major yield losses in some hybrids as the result of strong windstorms in late June and July.
4. Select hybrids with resistance and/or tolerance to the most common stalk rots, foliar diseases, and ear rots. These include northern corn leaf blight, gray leaf spot, Gibberella, Anthracnose and Diplodia stalk rots and Gibberella and Diplodia ear rots. More rust on corn was reported in 2017 than normal, including both common rust and southern rust. The latter is rarer but the more damaging of the two major rust diseases that affect corn in Ohio (https://agcrops.osu.edu/newsletter/corn-newsletter/2017-22/southern-rust...). 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 university/extension, 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 sites and years, consult the sortable “Combined Regional Summary of Hybrid Performance” tables available online http://www.oardc.ohio-state.edu/corntrials/regions.asp?year=2017®ion=State .