Farm Progress

What to know about plant growth regulators

Is this the year you should try PGRs in your crop management program?

Tom J. Bechman, Midwest Crops Editor

May 24, 2024

3 Min Read
closeup of corn seedlings just emerged
EARLY-SEASON DEVELOPMENT: Crop scouting and digging indicate these seedlings are off to a strong start. Jon Zuk with WinField United believes the right PGR products help ensure that result. WinField United

Would you try a product if you’d never heard of that category of compounds? Odds are you would say, “No thanks.” But what if your input supplier suggested a product with a proven track record for increasing yields? The term “PGR” may mean nothing to you. On the other hand, a 3-bushel-per-acre corn yield increase over time in reputable plots might be worth investigating.

Here is your chance to learn more about plant growth regulators, or PGRs. WinField United markets PGRs with a proven track record.

“PGRs have been around for over 20 years,” explains Jon Zuk, crop protection product manager for WinField United, covering Wisconsin, Minnesota and northern Illinois. “However, we’ve learned that the keys to maximizing performance are having the right ratio of individual PGRs in the plant and formulating solutions in the right way.”

All about PGRs

If you are not familiar with PGRs, here’s a brief introduction:

Classes. There are five classes of plant growth regulators: auxins, gibberellins, cytokinins, ethylene and abscisic acid. Auxins help create more cells by stimulating cell division, Zuk explains. Gibberellins, which have no connection to the corn ear rot organism, initiate various plant development processes. Cytokinins help determine the role of various cells in plants.

Ethylene, which helps fruit ripen, and abscisic acid, related to dormancy, aren’t PGRs targeted in the attempt to improve plant growth.

Ratio. “The important thing is getting the ratio of the first three PGRs right when you develop a product,” Zuk says. “To get a positive response, the first three classes of compounds must be present in the ratio most beneficial to plants. We’ve zeroed in on this, especially in corn.”

Formulation. “The formulation of the PGR product is the key to having the right solution and source of PGRs in the plant,” Zuk says. In fact, ratio and solution are so important that WinField United holds two patents related to these properties.

Application method. In-furrow applications are the current method of choice for achieving consistent results, Zuk says. “Often you may be planting in cool, wet soil, and it’s ideal if emerging roots access the PGR compound quickly,” he notes.

He adds that 2-by-2 placement can work, and foliar applications are also possible. If you’re going to make a foliar application, choose a product designed for it.

Example products. Ascend 2 is one of the latest PGRs offered by WinField United. Ascend 2 and Ascend Pro are both formulated specifically for in-furrow application in corn. Ascend SL is the company’s PGR for foliar applications in all crops.

Results. Four years’ worth of yield data from 67 Answer Plots in the company’s test plot program indicate a 3-bushel-per-acre advantage for a PGR vs. no PGR. These results include only in-furrow placement of Ascend 2 at 5.3 fluid ounces per acre.

Some local testing outside these plots included 2-by-2 placement. “It is possible to see the benefit later with 2-by-2 placement, once roots access it,” Zuk says.

Other uses. If you’re applying the PGR in a foliar application in corn, V5 to V8 or tasseling are recommended times, Zuk says. In soybeans, apply at R1 to R3 stages.

Read more about:

Plant Growth Regulator

About the Author(s)

Tom J. Bechman

Midwest Crops Editor, Farm Progress

Tom J. Bechman became the Midwest Crops editor at Farm Progress in 2024 after serving as editor of Indiana Prairie Farmer for 23 years. He joined Farm Progress in 1981 as a field editor, first writing stories to help farmers adjust to a difficult harvest after a tough weather year. His goal today is the same — writing stories that help farmers adjust to a changing environment in a profitable manner.

Bechman knows about Indiana agriculture because he grew up on a small dairy farm and worked with young farmers as a vocational agriculture teacher and FFA advisor before joining Farm Progress. He works closely with Purdue University specialists, Indiana Farm Bureau and commodity groups to cover cutting-edge issues affecting farmers. He specializes in writing crop stories with a focus on obtaining the highest and most economical yields possible.

Tom and his wife, Carla, have four children: Allison, Ashley, Daniel and Kayla, plus eight grandchildren. They raise produce for the food pantry and house 4-H animals for the grandkids on their small acreage near Franklin, Ind.

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