Aspergillus flavus Infection and Aflatoxin Accumulation in Resistant and Susceptible Maize Hybrids

Area of Science:

• Agricultural Science
• Plant Pathology
• Mycology

Background:

• Maize kernel infection and aflatoxin contamination by Aspergillus flavus pose significant threats to crop yield and food safety.
• Understanding the temporal dynamics of infection and toxin accumulation in different maize hybrids is crucial for developing effective management strategies.

Purpose of the Study:

• To monitor maize kernel infection and aflatoxin accumulation by Aspergillus flavus over the growing season.
• To compare infection and aflatoxin levels in maize hybrids resistant and susceptible to Aspergillus flavus.

Main Methods:

• Field studies were conducted over two years in Mississippi.
• Maize hybrids were inoculated with Aspergillus flavus conidia seven days after midsilk.
• Inoculated ears were harvested at multiple time points (35, 42, 49, 56, and 63 days after midsilk) to assess kernel infection and aflatoxin contamination.

Main Results:

• Differences in aflatoxin levels between resistant and susceptible hybrids were observed at all harvest dates.
• Significant differences in kernel infection were noted from 42 days post-midsilk onwards.
• Maximum differences in aflatoxin levels and highest kernel infection incidence were observed 63 and 49 days post-midsilk, respectively.

Conclusions:

• Resistant maize hybrids demonstrate a capacity to limit Aspergillus flavus infection and subsequent aflatoxin accumulation throughout the growing season.
• Temporal monitoring reveals that differences between resistant and susceptible hybrids become more pronounced later in the season.
• Specific resistant hybrids (Mo18W × Mp313E, Mp420 × Tx601) showed significantly lower aflatoxin levels compared to susceptible ones at 63 days post-midsilk.