A new scientific study suggests that widely reported increases in crop yields attributed to plant breeding may be significantly overstated, raising questions about how agricultural progress has been measured for decades.
Researchers examined the traditional method used globally to estimate genetic gains in crops. This approach typically compares the performance of older crop varieties with newer ones grown under the same conditions. The difference in yield is then attributed to improvements achieved through plant breeding.
According to the study, this method can blur the distinction between two important factors influencing crop productivity. One factor is genuine genetic improvement that raises the maximum yield potential of a crop. The other is maintenance breeding, which helps crops maintain productivity by improving resistance to diseases, pests, and environmental stresses.
Because both of these effects are captured in the same measurement process, the contribution of breeding to overall yield growth may appear larger than it actually is.
To examine the issue more closely, the research team analyzed data from 849 wheat cultivars tested across 17 locations in Argentina, France, the United Kingdom, and the United States. Their findings showed that wheat yields increased on average by about 73 kilograms per hectare per year during the study period.
However, the analysis found that only about half of that increase was attributable to genuine improvements in the crop’s inherent yield potential. The remaining gains were largely tied to breeding strategies that maintain productivity as environmental pressures evolve.
Maintenance breeding plays a crucial role in modern agriculture by enabling crops to cope with changing conditions, including emerging plant diseases, shifting pest populations, and climate variability. These improvements help stabilize yields and prevent declines in production, but they do not necessarily increase the biological ceiling of a crop’s production.
This means that a portion of the yield growth often attributed to plant breeding may actually reflect efforts to protect crops from losses rather than breakthroughs that dramatically increase maximum harvest levels.
The findings have important implications for agricultural research and global food security planning. As the global population continues to grow and climate challenges intensify, accurately measuring genetic progress in crops is essential for guiding investments in breeding programs and agricultural innovation.
Researchers involved in the study argue that new evaluation methods are needed to separate true genetic gains from maintenance effects. More comprehensive testing across diverse environments could help scientists better understand how breeding contributes to long-term improvements in crop productivity.
Although the research focused specifically on wheat, the authors believe the same issue may affect yield assessments in other major crops, suggesting that current estimates of breeding-driven yield growth may need to be reconsidered.
