Increasing the Genetic Diversity of U.S. Northern Corn Belt Hybrids with Tropical and Temperate Exotic Germplasm

The NDSU EarlyGEM or the Early Germplasm Enhancement of Maize (Zea maize L.) is a long term incorporation program designed to increase the genetic diversity of short season hybrids. Starting in 1999, exotic GEM breeding crosses derived from temperate accessions: BR52051, CH05015; tropical accessions: SCR01, CUBA17, FS8B; and tropical hybrid DKB844 along with late checks: B73, Mo17, and Iowa Stiff Stalk Synthetic (BSSS), were adapted to short-seasons and incorporated via a modified backcross (BC) procedure. This study was designed to assess the genetic diversity in exotic derived BC1:S1 lines and their competitive potential as sources of new and unique hybrids. Useful genetic diversity was evaluated with testers belonging to opposite heterotic groups, LH176 representing a non stiff stalk and TR3026 x TR2040 a stiff stalk testers and were tested in five North Dakota environments over two years (2009 and 2010). All the traits showed highly significant (P