Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/15/1996
Publication Date: N/A
Technical Abstract: A major goal in my maize research program at Raleigh, NC, has been the development and evaluation of more efficient methods for improving quantitative traits, particularly grain yield, using marker technology. A few historical remarks will be made in the discussion. However, the primary focus will be on several studies involving the single-cross hybrid (B73 x Mo17). In a major study of the genetic basis of heterosis, the results on grain yield appeard to be provide rather convincing evidence for overdominant gene action. However, further studies now indicate that dominance at linked loci (repulsion phase) is probably the most likely type. Targeted chromosomal segments from inbred lines Tx303 and Oh43 have been transferred into B73 and Mo17, respectively, using marker-facilitated backcrossing. Hybrids from the resulting "enhanced" lines have yielded 10 to 12% (1.0 to 1.25 t/ha) more grain than commericial check hybrids in NC and Cornbelt tests. New breeding methods for developing elite lines will be dicussed that do not require mapping of QTLs in advance of line development.