University of Illinois study finds genetic weakness in corn breeding

A study led by researchers at the University of Illinois Urbana-Champaign has identified a significant genetic weakness in the breeding stocks used for corn production. The findings indicate critically low genetic variation within certain inbred lines, which could threaten the ability of breeders to develop high-yielding hybrids in the future.

Modern corn breeding relies on heterosis, or hybrid vigor, created by crossing two genetically distinct groups: stiff-stalk (SS) and non-stiff-stalk (NSS). While these groups remain distinct, the individual inbred lines within them have become increasingly similar due to the repeated selection and reuse of top-performing lines. This reduction in in-group variability means that future crosses between the two groups may no longer guarantee the superior performance typically seen in hybrids.

The research specifically highlighted a lack of genetic variability related to grain yield in intermediate-maturity stiff-stalk lines. This particular group is the most commonly grown maturity type in the U.S. Corn Belt and accounts for nearly a third of global corn production. Scientists warn that this lack of diversity could hinder the development of maize capable of meeting yield goals amidst projected climatic challenges.