“Using this nested association mapping population, when we find associations with Southern corn leaf blight disease, we know we’re on the right street and maybe have the right house,” Holland says. “If we know which genes control disease resistance, we can make better predictions about which maize varieties will be resistant to disease and focus on breeding those lines.”

Holland and Balint-Kurti hope to build upon these results to learn more about how genes confer disease resistance to Southern corn leaf blight and whether they may also provide resistance to other similar types of diseases in corn and other plant species.

Southern corn leaf blight is a moderate problem in the Southeastern United States, Balint-Kurti says, and can be a significant problem in Southeast Asia, southern Europe and parts of Africa. Prevalent in hot, humid climates across the globe, it causes small brown spots on leaves. The spots get larger and eventually spread to the whole plant. Severe infections can cause major corn yield losses.

Balint-Kurti says the study provides “an unparalleled description of the genetic architecture of disease resistance.

“Southern corn leaf blight is a model system for pathologists to study. This research provides the most detailed description of the genetic basis of plant disease resistance of which we are aware,” he added.

In a companion paper in Nature Genetics, Holland and his Cornell colleagues found candidate maize genes related to leaf angle, an important trait that has allowed growers to plant corn crops closer together, resulting in drastically increased corn yields. That study also utilized the maize nested association mapping population.

The research was funded by the National Science Foundation and the USDA-ARS.