Wallaces Farmer

Corn hybrids: How to choose

Corn Source: Price, yield and standability are just some of the factors to consider among corn hybrids.

Terry Basol

October 22, 2020

4 Min Read
Ear of corn on stalk
BOTTOM LINE: Choose a diverse mix of corn hybrids to plant to reduce the risk associated with the weakness of any individual hybrid. Rod Swoboda

Seed companies offer price discounts if you order seed corn early, say prior to Jan. 1, for planting next spring. There are many things to consider when deciding which corn hybrids to plant in 2021 and price of seed is just one of them.

Yield is what everyone looks at first. What makes yield in your fields? Tolerance to corn diseases you’ve seen showing up should be part of your decision-making process. Grain drydown in the field is also an important factor.

Standability and stalk quality were put to the test this year in Iowa with drought conditions weakening stalks, causing increased lodging. The derecho windstorm in August across a wide area of Iowa’s midsection flattened many cornfields and parts of fields.

Early-season vigor helps get young corn plants well-established and off to a good start. Seed costs and trait options such as Bt for corn rootworm control are also considerations. Do you really need the corn rootworm control trait? Pencil it out. Can you save a few dollars per acre without it costing you in reduced yield?

Crop rotation and management practices should be considered. While the previous year’s hybrid genetics don’t have an influence on the current year’s hybrid performance, planting hybrids with the same insect and herbicide traits for several years in a row puts you at a greater risk of resistance development.

Yield vs. yield consistency

Genetic diversity is important, but yield is the most important factor to consider when choosing hybrids. The best production strategies will not result in high yields if you don’t choose high-yielding hybrids. Reevaluate your hybrids every year. Newer hybrids typically offer higher yield potential than those that have been on the market for several years.

Choose hybrids that have consistently high yield performance from location to location and year to year. To ensure this, look at multiple data sources including university trials, public hybrid trials, and seed company and retailer trials. Base your decision on as much data as you can to make good hybrid choices.

When considering transgenic options, look at which genetic traits are useful and effective in your fields. Many hybrids have traits for insect protection and herbicide tolerance. Think about whether you need all the traits or will use the traits available in a given hybrid, and evaluate whether transgenic hybrids would be more beneficial to your crop compared to conventional hybrids.

Risk management factors

Consider tolerance to disease. One way to prevent disease could be choosing a hybrid with resistance or tolerance to diseases typical in your farming environment. Look for disease ratings to minimize risk of infections. Consider whether corn hybrid disease ratings can be used to offset the need for in-season foliar fungicide application.

Grain drydown is important. When you evaluate hybrid drydown characteristics, also consider hybrid maturity. Earlier-maturing hybrids have a greater potential to dry down in the field, while later-maturing hybrids have less field drydown potential and greater risk of getting killed by fall frost. Be careful when choosing a hybrid for this reason. Both maturity selection and drydown can be used to achieve similar goals.

Standability and stalk quality ensure the corn is harvestable. While hybrids are often rated for standability and stalk quality, weather conditions during the growing season can have a big influence. You can help evaluate the performance of hybrids by doing a pinch test on cornstalks in your fields each year.

Early-season vigor helps give corn a good start and get an adequate stand established. Selecting hybrids with good early-season vigor can help protect against unpredictable weather conditions in April and May. Seedling vigor is also important if you plant into cover crops or high amounts of crop residue, or have typically cold, wet soils that could be encountered in no-till.

Weigh benefits, trade-offs

While hybrids should be planted in fields according to management practices used, realize that hybrid selection can be a key part of a pest management program. Transgenic traits and disease ratings can be used to determine if in-season foliar fungicides are needed, and traits can determine the herbicide program to be used. Weigh the benefits and trade-offs in your herbicide and fungicide programs, especially when considering conventional hybrids or various levels of traits included. Balancing the transgenic traits in a hybrid vs. the cost of alternative management can provide an opportunity to save money on seed costs although you have additional expense for pesticides.

For maturity selection, choose a range of hybrid maturities that will spread out the harvest season. This helps reduce risks such as moisture stress at pollination time and early frost. Choose hybrids that will reach maturity at least 10 days before the first average freeze for your area, to allow for grain drydown as well as provide a buffer in a cool year or if planting is delayed.

Prioritize yield potential and risk management when choosing hybrids. Choose a diverse mix of hybrids. Consider transgenic traits that may fit your farming situation. Evaluate hybrids based on disease resistance, potential for drydown and reaching maturity, and standability and early-season vigor. Plant new hybrids frequently to prevent resistance development. Keep cost in mind by balancing hybrid benefits with their price tag to ensure you make profitable decisions.

Basol is an ISU Extension field agronomist based at Nashua in northeast Iowa. Email [email protected].

 

About the Author(s)

Terry Basol

Terry Basol is an Iowa State University Extension field agronomist at Nashua in northeast Iowa.

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