Hybrid Corn Breeding Hit by Genetic Roadblock

A significant weakness has been discovered in the genetic makeup of hybrid corn breeding, which could impact global food production. Legacy hybrid corn breeding relies on 'hybrid vigor' or heterosis, where crossing parents from different heterotic groups results in superior offspring performance. However, a new study found that this method may no longer be effective due to the gradual reduction of genetic variability within the strongest performing lines.

The research examined 13 stiff-stalk and 28 non-stiff-stalk inbred corn lines, representing early-, intermediate-, and late-maturing types. The results showed a lack of genetic variability related to grain yield in intermediate-maturity stiff-stalk lines, which are commonly grown in the US Corn Belt.

This discovery could lead to diminishing returns in developing new hybrids that meet yield goals. Fortunately, there is still plenty of genetic variation in breeding germplasm and across traits in early- and late-maturing inbreds in both stiff-stalk and non-stiff-stalk groups.