2004 Annual Report 4.What were the most significant accomplishments this past year? D. Progress Report. This report serves to document research conducted under a specific cooperative agreement between ARS and the North Carolina State University. Additional details of research can be found in the report of the parent project 3625-21000-036-00D - ENHANCING AGRONOMIC AND VALUE-ADDED TRAITS OF CORN GERMPLASM. This project relates to the primary objectives of the parent project which includes coordination and conducting the GEM Project for the southern region, and development of germplasm focused on 50% tropical derivation. This report summarizes the research conducted under specific cooperative agreements between the ARS and N.C. State University. Additional details were reported at the December 2003 GEM Cooperators Meeting and the December TSG meeting. This subproject is concerned with nine aspects of the overall GEM effort. (1) The development of GEM families from breeding crosses. (2) Making topcross seed of the families. (3) Setting up appropriate experiments to compare the topcross families with commercial and experimental checks. (4) Providing seed for these experiments to 15 additional GEM collaborators. (5) Growing the experiments ourselves at several locations. (6) Analyzing and summarizing our own and our collaborators data. (7) Selecting the better materials for subsequent-year trials. (8) Conducting Grey Leafspot (GLS), and southern rust tests on the more advanced materials. (9) Increasing seed of better families, providing it to Ames and other GEM cooperators and to the NCRPIS. Ninety entries (out of 563 tested) have been advanced from first year to second year trials in 2004, and 25 entries (out of 164 tested) advanced from second year to third year testing. In 2004, 21,418 yield trial plots were coordinated through Raleigh (13,254 planted at NC locations). Approximately, 1,250 nursery rows, and 850 isolation block rows were planted in 2004 at Raleigh. Nursery work involves 17 new breeding crosses (populations not previously tested in any form). In 2003, an effort was made to evaluate GEM breeding crosses for yield per se as part of an overall effort to evaluate new material to work with. The data from this study revealed a great spread in yield potential and influenced our choices for 2004 nursery work Disease evaluation continues in 2004 for GLS and Southern Rust where only material in second year or later generations are evaluated. In 2004, nine new GEM lines were released to GEM Cooperators, and in 2003 more than two dozen other lines sib increased by the North Central Regional Plant Introduction Station in Ames for public distribution. Finally, we have begun routine screening of available tropical lines, as so little data are available to choose among them for use in GEM or other research. A summary of that work is to be submitted as an invited article for the 50th anniversary issue of Maydica. Collaborative work with other USDA-ARS scientists, and other public researchers includes fusarium molecular marker work with Drs. Holland (USDA-ARS, Raleigh), and Payne (NC State); racial classification using molecular markers with Drs. Buckler (USDA-ARS, Cornell), and Doebley (U. WI); and southern corn leaf blight resistance using molecular markers with Dr. Peter Balint-Kurti (USDA-ARS, Raleigh).