Standard measurement of genetic progress in agriculture may significantly overestimate gains in intrinsic crop yield potential

University of Nebraska-Lincoln study shows that half of reported wheat yield gains are due to "maintenance breeding" rather than increases in biological potential.

By: AXL Media

Published: Mar 4, 2026, 9:35 AM EST

Source: The information in this article was sourced from University of Nebraska-Lincoln

The challenge of measuring genetic progress

For decades, the agricultural industry has relied on a standard method to measure the progress of plant breeding: growing old and new crop varieties side-by-side to compare their outputs. This approach has traditionally been used to justify research investments and project future food security. However, new research published in Nature Communications indicates that this "side-by-side" method is fundamentally flawed. It fails to isolate the increase in a crop's inherent biological yield potential from the "maintenance breeding" required to keep those crops viable in an environment of shifting climate patterns and evolving pathogens.

Distinguishing yield potential from maintenance breeding

According to Patricio Grassini, a professor of agronomy at the University of Nebraska-Lincoln, annual increases in crop productivity are driven by two main factors: improved agronomic practices—such as better fertilizers and pest control—and genetic improvement. Within the category of genetic improvement, there is a vital distinction between raising the maximum yield a plant can produce under ideal conditions and the "defensive" breeding needed to prevent yields from dropping. The latter, known as maintenance breeding, ensures that modern varieties remain resistant to new diseases and environmental stressors that would otherwise cause older varieties to fail.

Analysis of 849 wheat cultivars across four nations

The international team examined data from 849 wheat cultivars tested across 17 locations in the United States, United Kingdom, France, and Argentina. On paper, these cultivars showed a consistent yield improvement of approximately 73 kilograms per hectare per year. However, when the researchers accounted for the declining performance of older varieties in the face of modern environmental threats, they found that only half of that improvement was due to an increase in actual yield potential. The remaining 50 percent of the gain was simply the result of maintenance breeding keeping the crop "running in place" against ecological challenges.