Genetic analysis could speed restoration of American chestnut trees.

A study in Science finds that genetic testing can identify chestnut trees likely to resist blight and grow tall, which can shorten breeding cycles and help efforts to restore the American chestnut.

The American chestnut once dominated eastern U.S. forests but was driven to functional extinction by an introduced blight and root rot by the mid-20th century. A new study published in Science reports that genetic testing of individual trees can identify which are most likely to resist disease and reach tall growth. That genetic information can shorten the time between generations used in breeding programs. Authors aim to combine the American chestnut's form with disease resistance traits found in the Chinese chestnut. Key findings: - Researchers sequenced genomes from multiple chestnut types and located many genomic regions linked to height and disease resistance. - Genetic testing can predict which offspring are likely to show desirable traits years before those traits appear in the field. - The breeding approach described aims to retain roughly 70%–85% American chestnut DNA while increasing resistance to blight and root rot. - An accompanying commentary noted gene editing as a potentially faster, more precise option, while also pointing to social and regulatory barriers. - Some conservationists and historians expressed concern about how much genetic change is acceptable before a tree is no longer considered an American chestnut. Summary: The study suggests genomic analysis can accelerate selection for disease resistance and stature, shortening breeding cycles and potentially speeding restoration over coming decades. Authors reported plans to apply these genomic tools in breeding programs and to continue scientific and regulatory discussions about gene editing and hybrid approaches.