MAIZE POPULATIONS WITH RESISTANCE TO FIELD CONTAMINATION BY AFLATOXIN-B1

Maize (Zea mays L) germplasm is needed with resistance to infection by Aspergillus flavus and/or subsequent contamination by aflatoxin B1 (AFB1). A select group of maize populations were evaluated for their resistance to AFB1 contamination at three locations. Four populations (Ibadan B and three others derived from crosses between Corn Belt inbreds and diploid perennial teosinte, Zea diploperennis) were compared with a susceptible hybrid check in a randomised complete block experiment with 10 replicates in Georgia, Missouri and South Carolina for two years. Ears were not inoculated, and naturally occurring concentrations of AFB1 in harvested grain were analysed for population differences. Ibadan B and Mo20W x Z diploperennis had significantly lower average amounts of AFB1, 19-mu-g kg-1 and 18-mu-g kg-1, respectively, than other test entries. Backcrossing to susceptible Corn Belt inbreds produced populations as susceptible as the check when resistance was measured as the concentrations of AFB1 in the grain. The consistency and significance of low AFB1 concentrations for Ibadan B and Mo20W x Z diploperennis suggest that these may be useful sources of resistance.