Most seed companies publish gray leaf spot ratings for their hybrids. Both single-gene and polygenic resistance are available, but the polygenic type is more common. There are many hybrids available with good resistance to northern leaf blight, and most seed companies publish ratings. Eyespot of corn Resistance is polygenic. Most hybrids do not have a high level of resistance, but in recent years, some moderately resistant hybrids have become available.
Some seed companies publish eyespot ratings for their hybrids.
Most hybrids grown in Iowa have some polygenic resistance to common rust, anthracnose, and northern leaf spot. Some hybrids will be more resistant than others. Single-gene resistance to rust and anthracnose may be available in a few hybrids. Most hybrids do not have much resistance to southern rust. Some companies publish ratings for some of these diseases.