2007 Annual Report 1a.Objectives (from AD-416) The objective of this research is to provide information and germplasm that will be used by private seed companies to create corn hybrids that resist accumulation of aflatoxin. 1b.Approach (from AD-416) Demonstrate that commercially acceptable inbreds and hybrids can be created by using molecular markers to incorporate chromosome regions with genes for resistance from two different donor sources of resistance to A. flavus and alfatoxin production; continue to identify molecular markers linked to genes for resistance to Aspergillus ear rot and to aflatoxin production in donor sources Mp313E, Tex6, M182 and Oh516; determine the genetic basis of resistance to aspergillus ear rot and to aflatoxin production for identified sources and aflatoxin-susceptible and aflatoxin-resistant plants and perfrom molecular marker analyses of the DNA samples to identify associated chromosome regions. 3.Progress Report This report documents accomplishments under a Specific Cooperative Agreement between Agricultural Research Services (ARS) and the University of Illinois. Additional details of research can be found in the parent project 3620-42000-033-00D entitled "Fungal Endophytes of Maize: Gene Products Conferring Resistance to Aflatoxin and Fumonisin". The Authorized Departmental Officer's Designted Representative monitors the project by: e-mail corrspondence, telephone calls, visits during the Annual Aflatoxin Elimination Workshops, and annual review of the research proposal submission including the previous year's research results. Toxic fungal metabolites known as mycotoxins contaminate maize grain produced throughout the world and represent a major food safety problem. While conventional breeding has produced commercial maize hybrids with substantial resistance to Fusarium graminearum (deoxynivalenol and zearalenone), efforts to produce hybrids with adequate resistance to Aspergillus flavus (aflatoxin) and F. verticillioides (fumonisin) have proven more difficult, and effective practical control practices are lacking. The objective of this research is to use molecular markers associated with chromosome regions conditioning resistance to Aspergillus ear rot and aflatoxin production, and to backcross resistance from unadapted agronomically poor (but resistant) inbreds into commercially used (but susceptible) inbreds. Depending on environmental conditions, this should greatly reduce or eliminate the amount of aflatoxin produced in grain of commercially used corn hybrids. Marker-assisted backcrossing was used in the creation of these aflatoxin-resistant inbreds from inbred lines with good agronomic characteristics that can be used directly by seed companies to produce hybrids, or as sources of resistance. The first commercial bag quantities (80,000 kernels per bag) of aflatoxin resistant hybrids were produced using aflatoxin resistant inbreds developed in this research program. The resistant hybrids have 50 to 80% less aflatoxin than hybrids produced from susceptible inbred parents. Hybrids from crosses between two resistant parents were also shown to be low in aflatoxin in an inoculated trial in southern Texas. The research seeks to eliminate preharvest aflatoxin contamination of corn, and therefore will benefit the entire corn industry, including corn seed producers, corn growers, grain exporters, corn milling companies, and food and feed manufacturers.