How Genetic Gain Becomes Yield: Reading Performance Data

The short answer

Genetic gain is the yield and quality improvement a breeding program builds into each new variety. In seed catalogues and provincial guides it is reported three different ways: as a percentage of a check variety in registration trials, as a percentage or bushel difference in provincial variety guides, and as an average from crop insurance data covering thousands of real farm fields.

All three are valid. Comparing a number from one source against a number from another is where growers get misled, because the same variety can honestly be described two different ways depending on which dataset is quoted and which variety it was measured against.

This page explains what each number means, why one variety can carry two different yield figures, and how to work out which figure applies to your own acres.

What genetic gain actually is

A breeding program starts with parent varieties chosen for specific traits, crosses them, and then selects through many generations for the combination it is after. Genetic gain is the cumulative result of that work: each successive variety carries a little more yield potential, a little better disease package, or a little more standability than the one it replaces.

Parentage is the fastest way to read a breeder’s intent. SY Manness traces to Faller, a parent known for yield, and the variety reflects it – it was the highest yielding CWRS in the 2020 MCVET trials. AAC Hockley traces to Alsen, Amidon, CDC Plentiful, Grandin and Infinity, a much broader base, and it delivers a broader package: rated MR or better for all Priority 1 diseases. AAC Viewfield traces to Glenn and Stettler and came out as a short semi-dwarf built for dry conditions and standability.

Gain does not arrive evenly across every trait. A variety bred hard for yield may hold protein rather than raise it. AAC Magnet came out of registration trials with the lowest DON content of all the checks, which is a gain in grade protection rather than in bushels. Reading a variety well means knowing which kind of gain you are being offered.

What percent of check means

A check variety is an established, widely grown variety that new entries are measured against. Both are grown in the same trials, the same years, at the same sites, so the comparison is like for like. A variety reported at 112% of the check yielded 12% more than that check in those trials.

It does not mean 12% more than your farm average, and it does not mean 12% more than a different variety measured against a different check.

Percent of check, as published on FP Genetics variety pages

Three rules follow from that table. Check the check: CDC Silas at 112% of Carberry and AAC Hockley at 103% of AAC Brandon cannot be ranked against each other, because Carberry and AAC Brandon are different bars. Check the years and sites, since a percentage from three years at twenty sites is a stronger signal than one year at four. And check the geography, because a Western Canadian average can hide large regional differences.

Why the same variety shows different numbers

SY Manness

The FP Genetics variety page reports that SY Manness averages 18% higher yield than AAC Brandon on MASC crop insurance data from 2022 to 2024. The 2026 Manitoba Seed Guide table on the same page reports it at 80 bu/ac, or 107% of AAC Brandon at 75 bu/ac, with 14.1% protein, 100 days to maturity and 76 cm height.

18% and 107% look contradictory. They are not. The first is an average of insured farm fields across a three-year window, where growers chose their own ground, inputs and management. The second is a variety guide table built from replicated trial data. Different dataset, different question, both accurate.

2026 Manitoba Seed Guide, as published on FP Genetics variety pages

AAC Hockley

AAC Hockley is reported as averaging 5.8 bu/ac higher yielding than AAC Brandon on Crop Insurance data from 2022 to 2024, at 103% of AAC Brandon in Areas 3 and 4, and provincially at 4.5% over AAC Brandon in Manitoba, 11.4% in Saskatchewan and 1.7% in Alberta.

That last line is the most useful number on the page, and it is the one most often skipped. The same variety delivers a large advantage in one province and a marginal one in another. If you farm in southern Alberta, the Western Canadian average is not your number.

The four data sources, side by side

What each source is good for

The practical version: use provincial guides to build a shortlist, use crop insurance data to sanity check what the variety does on real farms near you, and use registration and head-to-head trial data to understand the specific traits you are buying.

Reading the ratings beside the yield number

Disease ratings

Ratings run R for resistant, MR for moderately resistant, I for intermediate, MS for moderately susceptible and S for susceptible. AAC Viewfield is rated R for stem rust and stripe rust, MR for leaf rust and bunt, and I for fusarium head blight. Where a variety page states MR or better for all Priority 1 diseases, as AAC Hockley does, that is a statement about the whole package rather than a single disease.

Lodging and standability

Lodging is rated on a 1 to 9 scale where lower is better. AAC Viewfield sits at 1.4, rated Very Good, and holds the highest standability ratings in its class. SU Cossani is 1.8, also Very Good. AAC Succeed VB and AB Hague are 2.7, rated Good. On a high-yielding crop in a wet finish, that difference is the difference between a straight cut and a rescue job.

Maturity and height

Both are usually published as a difference from a reference variety rather than an absolute. AAC Viewfield is 0.9 days earlier and 4.4 cm shorter than Carberry. SU Cossani is 2 days earlier and 9 cm shorter than Hazlet. Earlier maturity spreads harvest risk; shorter straw generally means better standability.

Quality

Protein, test weight and kernel size determine grade, and grade determines the cheque. SY Manness carries 14.1% protein against AAC Brandon at 14.5% in the 2026 Manitoba Seed Guide table, alongside a 5 bu/ac yield advantage. Whether that trade favours you depends on your buyer and your protein premiums.

How to apply this to your seed decision

• Start with your province’s variety guide rather than a national average, and note which check variety the table uses.
• Ask for crop insurance figures for your risk area, not for Western Canada as a whole.
• Compare varieties only where they share the same check and the same trial years.
• Read the disease and lodging ratings before the yield column if you farm in a fusarium or lodging risk area.
• Decide what your grade depends on – protein, DON, sprouting, colour – and weight that trait accordingly.
• Ask your Territory Manager for registration, provincial guide and crop insurance data on the same variety, side by side.