2007 Annual Report 1a.Objectives (from AD-416) Develop superior silage germplasm from GEM sources to enhance silage quality and yield. 1b.Approach (from AD-416) Conduct agronomic and quality assessments in replicated yield trials in Madison and Arlington, WI. Traits measured include forage yield at 35% whole plant dry matter, neutral detergent fiber (NDF), in vitro digestibility of ND (IVNDFD), crude protein (CP), and starch. A selection index will be used based on potential milk production per acre. The following sources of germplasm will be used:. 1)~25 new GEM topcrosses based on 2003 GEM trial data,. 2)~160 topcrosses involving lines derived at the UW from GEM populations CUBA164:S15, CUBA117:S1520, URZM13085:N0204, ARZM17026:N1013, ARZM17026:N1019, SCRO1:N1310, CH05015:N15, and DKXL370:N11a20. 3.Progress Report This report serves to document research conducted under a specific cooperative agreement between ARS and the University of Wisconsin. Additional details of research can be found in the report for the parent project 3625-21000-047-00D, "Germplasm Enhancement of Maize Project (GEM)". This project relates to the primary objectives of the parent project which includes the development and evaluation of value-added traits such as silage nutritional quality and yield. In 2007, work continued with the GEM Quality Synthetic (GQS), which was created with the two Cuban populations, CUBA164:S1517, and CUBA117:S1520. Twenty S2 families were selected from GQS based on top cross results with the Wisconsin Quality Synthetic (WQS) in 2006. These 20 families are being intermated in 2007 to form GQS C1. Approximately 100 new GEM families are being evaluated in yield trials in two locations (Arlington and Madison, WI). The new families include lines derived from AR17056:N2025, DK212T:N11a12, FS8B(T):N11a, SCRO1:N1310, and CH05015:N15. Nutritional evaluations will be made and include assessment of neutral detergent fiber (NDF), in vitro true digestibility (IVD), in vitro NDF digestibility (IVNDFD), crude protein (CP), and starch concentration. Lines for potential release are being retested in 2007 from promising GEM families CH05015:N15, CHIS775:S1911b, and SCRO1:N1310. Developmental breeding is being continued on 110 GEM families in 2007, and new top crosses are being made for 2008 evaluation. The methods for monitoring activities include (1) observing germplasm developed by the Cooperator, and (2) progress reports submitted by the Cooperator in July and December for the Annual GEM Cooperator Meeting. E-mail exchanges were periodically initiated by the ADODR or Cooperator on status of experiments during the growing season, and new germplasm resources were exchanged for silage (germplasm provided by ADODR) and lignocellulosic ethanol experimentation in Ames (germplasm provided by Cooperator). Top crosses of silage lines developed by the Cooperator have been planted and observed in the Ames Field Day demonstration plot. A site visit by the Cooperator to Ames is planned in September.