Stacking a plant growth regulator with a foliar fungicide lifted barley yield 28 per cent — or 27 bu/ac (1.452 t/ha) — at Yorkton, Saskatchewan, in 2024, according to a two-year SaskBarley-funded study across five Agri-ARM sites.

The Yorkton result was additive: Moddus (trinexapac-ethyl) alone added 11.4 per cent (12.6 bu/ac / 0.677 t/ha), and Trivapro fungicide alone added 14.8 per cent (14 bu/ac / 0.753 t/ha). No other site-year showed a significant response to the combined treatment.

What did the trials test?

The research ran in 2024 and 2025 at Indian Head, Melfort, Scott, Swift Current and Yorkton. Four varieties were evaluated: AAC Prairie and CDC Churchill (malt), and CDC Durango and AB Wrangler (feed). Treatments combined standard or enhanced N, Moddus at GS30-32 and Trivapro at flag leaf in a full factorial.

N rates scaled to yield potential:

• Swift Current (low): 100 versus 125 lb N/ac (112 to 140 kg/ha)
• Indian Head and Scott (mid): 120 versus 150 lb N/ac (134 to 168 kg/ha)
• Yorkton and Melfort (high): 130 versus 162 lb N/ac (146 to 181 kg/ha)

Mike Hall, research manager (retired) at the East Central Research Foundation (ECRF) at Yorkton, said the work was designed to outrun variety turnover. "These varieties are very new and are anticipated to become popular in the future," he said. "If they do indeed become popular, we will hopefully have data to advise farmers when they are currently growing these varieties and not after they've moved on to other varieties."

When did PGRs pay?

Moddus shortened crops across both seasons and cut lodging at most site-years. Lodging fell significantly everywhere except Swift Current (2024 and 2025), Indian Head (2025) and Yorkton (2025). CDC Durango, which carries very good stem strength, did not respond to PGR at Melfort in either year. AB Wrangler, rated fair for lodging, responded at Melfort in 2025.

Yield gains from PGR were rare. Yorkton 2024 was the only site to show a PGR-driven yield increase, with grain protein falling 0.94 per cent through dilution. The opposite happened at Swift Current in 2025, where PGR cut yield for AAC Prairie and CDC Churchill after a dry start and late-summer rain triggered secondary growth.

Hall flagged the season as anomalous. "Swift Current (2025) was an unusual site with unusual results," he said. "The year started out dry, then precipitation was received in late summer, resulting in secondary growth providing the majority of the yield."

The broader rule: drought-stressed crops lost yield, kernel plumpness, test weight and thousand kernel weight when Moddus was applied.

How did fungicide perform?

Leaf disease stayed low at most sites, so fungicide responses were limited. Yorkton 2024 produced the largest bump at 14.8 per cent (14 bu/ac / 0.753 t/ha). Melfort 2024 added a more modest 5 bu/ac (0.269 t/ha), a 4 per cent lift despite low disease ratings.

At Swift Current in 2025, fungicide lifted the two malt varieties AAC Prairie and CDC Churchill under low disease pressure. The yield gains may stem from Trivapro's water-use-efficiency health claim, Hall suggested. Test weight occasionally rose with fungicide, while grain protein was largely unaffected.

Did extra nitrogen lift yields?

Higher N rarely moved yield. The exceptions:

• Melfort 2024: +3.3 per cent
• Yorkton 2025: +22 per cent
• Swift Current 2025: yield fell, driven by the malt varieties

Grain protein rose at every site-year except Swift Current in both years. Mitchell Japp, research and extension manager at SaskBarley, said barley growers need to plan N around end use. "We did not see a lot of differences between varieties in the study," he said, "but varieties with better stem strength did not respond as consistently to PGR application."

What should growers watch next?

Three rules emerge. Apply Moddus only when lodging risk is high, in high-yield environments or on weaker-stemmed varieties. Avoid PGRs in drought — yield, plumpness and test weight all decline. Run fungicide where disease pressure justifies the spend; the 2024 Yorkton numbers set a realistic ceiling on upside.

Nitrogen decisions still hinge on soil tests, yield targets and end-use market. Elevated rates lift yields under adequate moisture but raise protein in dry seasons — a deal-breaker for some malt contracts. SaskBarley and the Agri-ARM network are expected to extend the dataset into 2026, with a fuller economic and grain-quality summary due once results are compiled.