Two University of Missouri College of Agriculture, Food and Natural Resources faculty members’ work has been showcased in Science. Published in the journal’s August issue, the co-authors’ two articles describe a massive genetic resource geneticists and breeders can use to unlock the basis of corn diversity.

The faculty members, Plant Sciences Adjunct Professor Michael McMullen and Adjunct Assistant Professor Sherry Flint-Garcia, work as research geneticists with the USDA Agricultural Research Service (ARS), the principal intramural scientific research agency of the U.S. Department of Agriculture.

The articles, “Genetic Properties of the Maize Nested Association Mapping Population” and “The Genetic Architecture of Maize Flowering Time,” describe how the scientists found that most natural genetic variation in corn is the product of numerous genes working together, each with a small effect that could be manipulated by breeders.

Developed by ARS scientists with major funding provided by the National Science Foundation, the researchers’ project provides major insights into hybrid vigor, a key element of today’s high-yielding crops. The scientists’ findings will change the way breeders improve crops using high-efficiency molecular technologies.

Hybrid vigor is responsible for the incredibly productive corn hybrids grown across the United States. The researchers found that hybrid vigor results in part from hybrids bringing together optimal gene combinations that are unlikely to occur in current breeding schemes. Novel breeding schemes designed to exploit this new knowledge of gene combinations will accelerate plant breeding worldwide.

These findings also may help researchers determine the role of genes in agronomic traits such as yield, fertilizer-use efficiency, drought tolerance and ethanol potential.

In their research, the scientists developed and assessed more than 1 million corn plants, making their project the largest published genetic corn study to date. Corn (maize), one of the world’s most important food crops, is also genetically 15 times more diverse than the human genome. So it’s important for scientists to learn about key gene variants in the maize genome and the role those variants play in corn traits.

McMullen and Flint-Garcia conduct their research at the ARS Plant Genetics Research Unit in Columbia, Mo.

Research objectives of the ARS maize research group:

• Determine if altering expression of genes that exhibit evidence of past selection during maize domestication and improvement modifies the expression of currently relevant agronomic traits.
• Develop strategies and mechanisms for improving drought-stress tolerance of maize.
• Conduct an analysis of the role of transcription factors in controlling agronomic traits in maize.

The ARS scientists in the project were led by plant geneticist Ed Buckler at the agency’s Robert W. Holley Center for Agriculture and Health in Ithaca, N.Y.