|Marshall, L - MONSANTO, WILLIAMSBURG IA|
Submitted to: Aflatoxin Workshop
Publication Type: Abstract Only
Publication Acceptance Date: October 27, 2000
Publication Date: N/A
Technical Abstract: The seed coat or testa, underlying the pericarp, is a natural barrier and structural impediment to A. flavus infection of the maize kernel germ. Microscopic tears in the seed coat represent a critical susceptibility factor allowing A. flavus infection and aflatoxin contamination of otherwise undamaged grain. Previous cooperation with a corn seed company revealed that the harvested grain from A. flavus wound-inoculated ears of elite inbreds showed variation for the frequency of undamaged bright greenish yellow fluorescent (BGYF) kernels when examined under ultraviolet light (365 nm). The fluorescent kernels are evidence that A. flavus has penetrated seed coat defenses and infected the germ. Numbers of BGYF kernels have been related to levels of aflatoxin contamination of grain sampled following harvest. Selecting for reduction in the frequency of BGYF kernels in conventional maize breeding programs may result in lines with reduced susceptibility to seed coat tearing and thus provide protection against A. flavus and possibly other kernel molds. We plan to study the differences in BGYF kernel frequency in the progeny of breeding populations made by crossing lines that are relatively high (poor) for BGYF kernels with lines that are low (good), to see whether good lines can be recovered, and whether these "good" lines tend to result in reduced aflatoxin levels from hybrids made with these lines.