Fighting straw? Managing wheat height with a plant growth regulator

Semi-dwarf varieties of wheat that were introduced during the Green Revolution changed farming in many parts of the world, and changed the way people could farm. Before these shorter varieties came along, if you were lucky enough to grow a big crop, it would probably lie down.

New semi-dwarf varieties didn’t lodge as easily, enabling higher grain yields, but could still fall over, especially in high fertility situations. Enter plant growth regulators — another tool for managing wheat plant height.

Chlormequat chloride or “Manipulator,” a plant growth regulator sold by Engage Agro, was first registered in Canada in 2015. It was legal to use, but most grain buyers refused to accept wheat treated with Manipulator until the U.S. established a maximum residue limit for it earlier this year, in 2018.

Phil Benardin, territory representative with Engage Agro, discussed what growth regulators are and what they can do as part of the Sure Growth Field day near Marchwell, Sask. (Story continues below):

Bernardin says sales started off well this year, and then it got dry. “Original interest was really, really high. We were really happy with the original commitments we got from retails. Unfortunately, the dry weather hurt us a little bit in terms of on-the-ground sales.”

He notes the drop off in sales may be good for the long-term acceptance of the product. “It’s a good sign that the growers understood the product and that in a dry year it really wasn’t necessary. We’d rather have guys use it, and be happy with it, than use it and not like the results.”

Simply put, Bernardin says, “Manipulator is a plant growth regulator intended to help reduce lodging in wheat crops.” Some farmers report other advantages, such as increased combine efficiency, because of shorter straw, but this is not on the label and has not been verified.

The dry conditions this year show the flexibility of the product, as producers can push fertility, and if growing conditions are good, the plant can be sprayed to keep it from lodging. If growing conditions are not as good, you can choose not to spray.

Either way, something to think about as you sit in your combine, wishing your crop was a little taller, or a little shorter.

Related Wheat School episode: What we’ve learned so far in year one with Manipulator

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