Corn School: What are ‘tip back’ ears telling you?

Photo: David Hooker, University of Guelph

Corn yields in Ontario have been increasing 2 bu/ac, or one per cent per, year over the past 40 years.

Where is that yield increase coming from? University of Guelph associate professor David Hooker says genetics (65 per cent) and agronomy (35 per cent) are the key contributors to bigger corn crops. Corn breeders can take a bow for their efforts, but Hooker notes that understanding corn physiology and strong agronomic practices will help growers realize more of that genetic yield potential in their fields.

On this episode of the RealAgriculture Corn School, Hooker talks corn physiology 101 with host Bernard Tobin and how corn yields reflect a combination of genetics, environment, and management. In the video, Hooker looks at corn ear ‘tip back’ and why it’s important for growers to have a sound understanding of physiology and how it can impact their crop.

Every summer, Hooker gets questions from frustrated growers who see kernel abortion at the tip of ears in crops they believed were carrying huge yield potential as the crop moved through the V6 to V10 growth stages — when yield is determined by the plant. When those top kernels are aborted, Hooker says, the plant is telling growers that it’s under stress, possibly weather, moisture, or nutrient-related, and can’t fill the tip. (Story continues after the video.)

Hooker says growers can learn from these situations and make management adjustments in future years to support the plant’s nutrient needs and best manage environmental conditions.

Hooker also has some advice for growers who do not see tip back and have ears with every kernel filled to the tip of the cob. He sees an opportunity to more aggressively manage the crop. In this situation, growers may not be optimizing the yield potential of their genetics and growing environment. When the plant is filled to the tip, there was likely more yield available that could have been realized by pushing plant population, for example, to produce higher seed numbers per square metre and higher per acre yield, he notes.

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