My academic profile at ISU

MS PROGRAM AT IOWA STATE UNIVERSITY
Maize Protein Quality; Paul Scott, P.I.

Publications
Darrigues, A., C. Buffard, K.R. Lamkey, M.P. Scott. 2006. Variability and genetic effects for tryptophan and methionine in commercial maize germplasm. Maydica. 50:147-156

Maize (Zea Mays L.) is a major food and feed crop, however, maize proteins are nutritionally imbalanced due to low levels of certain essential amino acids, including tryptophan and methionine. The objectives of this study were (1)to determine the variability in methionine and tryptophan levels present in commercial maize inbred lines, (2) to characterize the genetic groups of commercial maize breeding germplasm for their methionine and tryptophan content, (3) to estimate general combining ability, specific combining ability, and reciprocal genetic effects for tryptophan and methionine content in this germplasm. Seventy-six inbred lines representing nine different genetic groups were evaluated. There was significant variability among the genetic groups and among the inbreds in some of the groups. Two six-parent diallel mating designs were completed with parents selected for low or high methionine or tryptophan levels. The analysis of the diallel crosses revealed significant general and specific combining ability effects, as well as reciprocal effects. These effects were of greater magnitude in the methionine diallel than in the tryptophan diallel. These studies suggest that methionine responds better to selection than tryptophan. Maize breeders will be able to exploit these genetic effects to develop hybrids with elevated levels of tryptophan or methionine.

Darrigues, A., K.R. Lamkey, M.P. Scott. 2006. Breeding for grain amino acid composition in maize IN Plant breeding : the Arnel R. Hallauer International Symposium (2003: Mexico City, Mexico), edited by K. R. Lamkey and M. Lee, chapter 24. Ames, Iowa: Blackwell Publishers.