Effects of xenia on Aspergillus flavus infection and aflatoxin accumulation in maize inbreds

Aspergillus flavus Link:Fries infection and aflatoxin contamination pose an economic threat to maize (Zea mays L.) producers of the United States. Efforts to identify germplasm resistant to A. flavus infection and aflatoxin accumulation have raised questions regarding the role of xenia, the pollen effect on the embryo and endosperm, in resistance of maize grain to the pathogen. The objective of this study was to evaluate the importance of xenia on A. flavus infection and aflatoxin accumulation in seed of eight inbred lines with different levels of resistance to A. flavus infection and aflatoxin contamination. Resistant and susceptible maize lines were hand-pollinated following a diallel mating design to produce seed for trials. The ears were inoculated 14 d after pollination with A. flavus spores. Grain was plated on agar to determine the extent of A. flavus infection and analyzed to measure aflatoxin content. Significant differences were detected among seed parents for both aflatoxin accumulation and A. flavus infection in both 2003 and 2004. The effects of pollen source were not significant on aflatoxin contamination or A. flavus infection in either 2003 or 2004. These results are consistent with xenia having little or no effect on A. flavus infection or aflatoxin accumulation. The results further suggest that reliable evaluation of A. flavus infection and aflatoxin contamination can be gained from open-pollinated field experiments.