ARS | Publication request: Evaluation of Combining Ability and Grain Quality of Quality Protein Maize Derived from U.S. Public Inbred Lines

Submitted to: Maydica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 7, 2009
Publication Date: January 2, 2010
Repository URL: http://www.maiscoltura.it/maydica/articles/54_449.pdf
Citation: Scott, M.P., Peterson, J.M., Hallauer, A.R. 2010. Evaluation of Combining Ability and Grain Quality of Quality Protein Maize Derived from U.S. Public Inbred Lines. Maydica. 54:449-456.

Interpretive Summary: Most of the corn grain produced in the world is used for food or feed, so the nutritional value of this grain is important. The amino acid balance of grain is one thing that limits the nutritional value of grain. One way to improve the amio acid balance of grain involves using a mutation called opaque 2. Varieties of corn that carry the opaque2 mutation and have acceptable agronomic properties are called Quality Protein Maize (QPM). Most QPM is not adapted to the U.S. Corn Belt. We developed and characterized the grain of several QPM inbred lines that are well-adapted to the U.S. Corn Belt. In addition, we characerized the agronomic performance of these lines in hybrid combinations. The information in this study will be useful to plant breeders on how best to use these lines in their breeding programs. In addition, it will enable biochemical and genetic studies of QPM by scientists in the U.S. Corn Belt. This work will facilitate development of QPM hybrids with improved nutritional quality.

Technical Abstract: Quality Protein Maize (QPM) has improved nutritional quality due to the opaque2 mutation as well as hard endosperm conferred by uncharacterized modifier genes. We have developed a series of QPM inbred lines based on crosses between public U.S. Corn Belt-adapted lines with QPM lines developed at the International Wheat and Maize Improvement Center (CIMMYT). The resulting inbred lines exhibit characteristics of other QPM germplasm including translucent endosperm and elevated content of the essential amino acids lysine and tryptophan. We characterized the genetic mechanisms controlling yield of hybrids made from the QPM inbred. For machine harvestable grain yield, specific combining ability was significant, while general combining ability was not, indicating that nonadditive genetic effects were important for determining the yield of these temperate QPM hybrids.