Genetic Composition of Contemporary U.S. Commercial Dent Corn Germplasm
- Mark A. Mikel *a
Germplasm of contemporary U.S. dent corn (Zea mays L.) is predominately from proprietary programs. Although publicly developed inbred lines contributed to the genetic foundation of these programs, their role is not known. The objective of this work is to identify and characterize major progenitors of contemporary proprietary germplasm through pedigree analysis of a set of 305 corn inbreds registered during the years 2004 through 2008 by U.S. Plant Variety Protection (PVP) and/or utility patent. Major progenitors found were the inbred lines Dekalb DK3IIH6 (12.2% genetic contribution), B73 (11.7%), and Pioneer Hi-Bred International (PHI) PH207 (9.5%). Using commercial hybrids as breeding germplasm was common during the 1980s and facilitated the introgression of PHI Iodent germplasm into competitor breeding programs. Of these, the PHI commercial hybrid 3737 has the greatest impact to contemporary germplasm by contributing 15.6% of the genes. Pedigree analysis of 1132 U.S. PVP and/or utility patent registered corn inbreds from 1984 through 2008 indicates that the genetic contribution of the public line Mo17 has decreased (from 8.6 to 1.7%) and the contribution of the public line Oh43 increased (from 1.5 to 3.9%), whereas the contribution of B73 remained constant. The contribution of Iodent germplasm increased concomitantly with use across commercial breeding programs.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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