Evaluation of GEM Germplasm for Multiple Insect Resistance and Fumonisin Concentration

The Western corn rootworm (WCR) and the European corn borer (ECB) are serious pests of maize in the U.S. Secondary infections with Fusarium verticillioides, F. proliferatum, and F. subglutinans occur after ECB larvae feeding, causing ear rots and contamination with fumonisin, a mycotoxin associated with severe animal and human health disorders. The tolerance of maize germplasm adapted to the Midwest against the ECB larvae was gradually improved over a 60 year period of continuous selection. However, improvements regarding WCR and Fusarium resistance over this time period are small. One big roadblock towards WCR and Fusarium host plant resistant maize genotypes is the apparent lack of genetic variation for these traits in the Midwestern maize pools. The overall objective of this project is the development of maize varieties with host plant resistance against WCR, ECB, and Fusarium adapted to U.S. growing conditions by broadening the genetic basis for these characteristics using exotic maize germplasm. The specific objectives of this project are to (1) evaluate newly developed GEM lines (per se and as testcrosses) for their resistance against WCR as well as ECB, (2) evaluate these genotypes for their resistance against Fusarium ear rot and fumonisin concentration, (3) study the genetic basis of insect resistance in maize against both insect species, and (4) initiate a recurrent selection program aimed to develop new maize lines with improved WCR resistance.