Evaluation of Exotic Temperate Accessions and Release of Introgressed Germplasm From the GEM Project.

The Germplasm Enhancement of Maize Project (GEM) is a cooperative effort of the USDA- ARS, land grant universities, private industry, international, and non-governmental organizations to broaden the germplasm base of maize. Top cross performance of exotic temperate maize accessions identified germplasm with superior breeding potential.  Accessions used in this study were reported in 1998 by Salhuana et al. and include temperate accessions from Argentina, Chile, USA, and Uruguay. All accessions were part of the Latin American Maize Project (LAMP). Trait evaluation of the derived lines made with breeding crosses from these accessions x elite adapted lines identified useful applications. Of the 202 germplasm sources released by the GEM Project during the past seven years, 47 were derived from breeding crosses made with exotic temperate accessions and 155 were from exotic tropical accessions. Release decisions were based on two year yield trial results and other important agronomic and grain quality trait evaluations. Seven of the eight most promising accessions reported in 1998 proved to be excellent germplasm sources for developing adapted GEM lines in the subsequent years. Among the 47 releases, 20 were developed from breeding crosses with accessions from Argentina (AR), 12 from the USA, 8 from Uruguay (UR), and 7 from Chile (CH). Some of the most important accessions included ARZM 17 056 for Corn Rootworm resistance; ARZM 16 026 and FS8A(S) for reduced grain fumonisin content; FS8B(T) for high yield, anthracnose, and silage; ARZM 01 150 for drought tolerance; ARZM 17 056 and CHZM 05 015 for high protein. Top cross performance of accessions x adapted lines can effectively be used to identify superior breeding potential of exotic germplasm, as previously predicted. Racial derivations, released lines, and specific trait characteristics will be presented.