Wheat School: What we've learned so far in year one with Manipulator


2018 marks the first growing season where farmers across Canada can apply the plant growth regulator chlormequat chloride — a.k.a. “Manipulator” — to wheat without having to worry about problems marketing the wheat after harvest.

The U.S. established a maximum residue limit (MRL) for chlormequat chloride in cereal crop imports this spring, clearing the way for grain elevators in Canada to accept spring wheat, winter wheat, and durum treated with the plant growth regulator or PGR.

With genetics, fertility, and management practices pushing wheat yields higher, many growers have been looking forward to having Manipulator as a tool to reduce crop height and increase stem strength to prevent lodging in crops with high yield potential.

Research conducted by Manitoba Agriculture in 2015 and 2016 showed an average 7 cm height reduction in wheat when Manipulator was applied.

Unfortunately, drier-than-normal conditions have reduced yield potential and plant height in parts of Western Canada this year.

While it’s too early to fully describe the impact Manipulator had on plant height and yield in 2018, one lesson that’s already been learned is that while it can be a valuable tool, Manipulator’s usefulness is still dependent on growing conditions, says Anne Kirk, cereal specialist with Manitoba Agriculture.

Wheat showing symptoms of drought stress in south-central Manitoba in late June.

“If your wheat is already pretty short and doesn’t have a big risk of lodging, it’s probably not the year to try it out,” she notes, in this Wheat School episode filmed in Carman, Man.

The label for Manipulator also states that it should not be applied to wheat that is under stress.

“In many areas of the province and the prairies we are seeing wheat that is drought stressed. As a plant growth regulator is a hormone, we may not know all the consequences of applying this plant growth regulator under stressful conditions,” she explains. (Learn more about the complex interaction between variety, chemistry and conditions in this throwback Wheat School episode on PGRs with Sheri Strydhorst of Alberta Agriculture).

Kirk will be discussing the use of PGRs at Crops-a-Palooza in Portage la Prairie on July 25th. (Register for the free field day here.)


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