Anatoxin accumulation in maize (Zea mays L.), caused by Aspergillus flavus,
is a serious and chronic problem in the southeastern United States. Identi
fication and development of resistant germplasm are crucial for developing
anatoxin-resistant hybrids. However, a lack of a reliable field-inoculation
method is a significant impediment to maize breeders' success. Previously
available inoculation methods resulted in extremely high coefficients of va
riation for anatoxin. We evaluated four non-injury inoculation methods at f
ive inoculation dates for studying concentration of anatoxin in contaminate
d maize kernels. Needle-in-silk channel (NSC) method involved injection of
A. flavus conidial suspension into an ear through silk channel with a syrin
ge; toothpick-in-silk channel (TSC) involved insertion of a Czapek medium-c
overed, conidia-laden toothpick in silk channel of an ear; toothpick-under-
husk (TUH) was similar to TSC, except that Czapek-covered, conidia-laden to
othpick was placed on the surface of kernels by making an incision in the h
usk in the middle of an ear; and bag inoculation (BAG) involved placement o
n an ear of an inoculation bag (a shoot bag) at the bottom of which was pla
ced 5 mt Czapek medium that was covered with A. flavus conidia. The toothpi
ck-under-husk inoculation method was judged most reliable for evaluating an
atoxin concentration differences, as indicated by a substantially reduced c
oefficient of variation (CV = 20.6%).