Researchers find wheat breeding gains partly due to adaptation does not yield potential
A new international study suggests that long-reported gains in crop yields from plant breeding may be higher than the actual improvements in genetic yield potential.
The research involved scientists from several institutions, including five experts from the University of Nebraska–Lincoln. Their findings challenge a widely used method that compares the yields of older and newer crop varieties grown side by side to measure genetic progress.
“The increases in crop productivity we see year by year can be explained mainly by two factors,” said Patricio Grassini, Sunkist Distinguished Professor of Agronomy and one of the researchers involved in the study. “One is improved agronomic factors like, for example, fertilizers, pest control and so forth. The other is genetic improvement.”
Researchers analyzed long-term wheat improvement using data from 849 wheat cultivars tested across 17 locations in Argentina, France, the United Kingdom, and the United States. The study found that wheat yields improved by about 73 kilograms per hectare each year.
However, the team discovered that only about half of this improvement resulted from higher genetic yield potential in modern wheat varieties. The remaining gains were linked to what researchers call “maintenance breeding.”
Maintenance breeding refers to the ongoing work plant breeders do to help crops stay productive as environmental conditions change. Over time, pests, diseases, and climate patterns evolve, which can reduce the performance of older crop varieties. Breeders regularly introduce new traits to protect crops against these threats.
These improvements help maintain stable production but do not necessarily increase the crop’s biological yield ceiling.
According to the researchers, the traditional method of comparing old and new varieties does not clearly separate improvements in true yield potential from gains that simply prevent yield losses. Because of this, the approach may overestimate how much breeding alone has increased productivity.
Researchers say understanding the difference between these two types of gains is important for agricultural planning and research investment.
Accurate measurement of genetic progress helps guide funding decisions and future breeding strategies. As global food demand continues to grow, scientists emphasize the importance of balancing investment between plant genetics and improved agronomic practices such as fertilizer management and pest control.
The researchers conclude that more advanced evaluation systems are needed. Multi-environment variety trials with proper comparison checks can provide clearer insights into how breeding contributes to yield potential.
Improved measurement methods will help scientists better understand crop progress and support strategies to strengthen global food production in the future.
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