Are Plant Growth Regulators (PGRs) Worth It for Your Barley Crop?
Chris Holzapfel, Research Manager at the Indian Head Agriculture Research Foundation (IHARF) presented at The BarleyBin LIVE at The Dam Smokehouse in Nipawin, SK in December 2024 about his recent agronomic research studying the effect on lodging when applying different rates and mixes of plant growth regulators (PGRs) to barley.
Watch the Recording
Here are the key takeaways:
Plant growth regulators (PGRs) have been gaining attention in barley production, particularly with the registration of chlormequat chloride (Manipulator) in 2020 and trinexapac-ethyl (Moddus) in 2021. While PGRs have been used regularly in wheat over the last 10 years or so, many barley growers are still unsure if they provide a clear return on investment. Research trials in Saskatchewan over the past few years provide some valuable insights. Here’s what you need to know before deciding whether to apply PGRs to your barley crop this year.
Understanding Plant Growth Regulators in Barley
PGRs are used to reduce plant height and improve lodging resistance in cereal crops, helping maintain harvest efficiency and protect yield potential. However, barley’s response to PGRs has been less consistent than wheat, making it crucial to assess your farm’s conditions before application.
What Research Shows: When Do PGRs Work Best?
Recent field trials conducted at Indian Head Agricultural Research Foundation (IHARF) and across Saskatchewan, funded by SaskBarley and ADOPT, have tested PGRs on multiple barley varieties under different environmental conditions. Key findings include:
- Moisture matters: PGRs show the most benefit in high-rainfall areas where lodging risk is high. In dry years, they provide minimal value, and can be detrimental.
- Lodging prevention: Moddus was more effective than Manipulator at reducing lodging, particularly in varieties like Churchill and Wrangler.
- Yield impact: In previous dry years, PGRs had little to no impact on yield. However, in 2024, Moddus increased yield by 10% in higher-moisture conditions that increased lodging pressure.
- Variety differences: Not all barley varieties respond the same way. Oreana, for example – a short, strong-strawed variety, showed minimal response to PGRs, while others benefited .
- Fertility balance: Higher nitrogen rates increased lodging risk, reinforcing the need to balance fertility with PGR application.
The Marketability Factor: Moddus vs. Manipulator
One important consideration is market acceptance. Manipulator is flagged on the Keep It Clean Product Advisory list for malting, as well as feed and foodbarley, which means using it could affect your ability to sell. Moddus does not have this restriction, making it the safer choice for growers targeting the malt market.
Should You Apply a Plant Growth Regulator this Year?
The decision to use PGRs depends on your farm’s moisture levels, barley variety, and lodging risk.
Use PGRs if:
- You farm in a high-rainfall area where lodging is a concern.
- You grow a variety known to be less resistant to lodging.
- You’re applying higher nitrogen rates and need to manage lodging risk.
Skip PGRs if:
- You farm in a dry area.
- You grow a variety with good lodging resistance.
Final Thoughts
PGRs are a situational tool for barley growers. While Moddus has shown strong results in reducing lodging and, in some cases, increasing yield, PGRs are not always necessary—especially in drier conditions. If you’re considering applying a PGR this year, take a close look at your moisture levels, variety selection, and marketability requirements before making your decision.
Have questions about PGRs for barley?
Reach out to Chris Holzapfel (cholzapfel@iharf.ca) or Mitchell Japp, Research and Extension Manager for SaskBarley (mjapp@saskbarley.com) directly for more research insights and best practices!
