Effects of N fertilization and hybrid genotype on fusarium and aspergillus mycotoxin contamination in maize kernels

Maize is an essential crop globally, serving multiple functions as food, animal feed, and a raw material for various industries, exhibiting greater versatility than wheat or rice. Nonetheless, its quality is compromised by three mycotoxin-producing funguses: Fusarium graminearum, Fusarium verticillioides, and Aspergillus flavus. This study aimed to evaluate the impact of varying nitrogen fertilization rates (0, 90, and 150 kg/ha) on the severity of fungal ear rots caused by the aforementioned pathogens, as well as on the levels of mycotoxin contamination (deoxynivalenol [DON], fumonisins [FBs], and aflatoxin B1 [AFB1]) in the kernels of three maize hybrids: DKC4590, GKT376, and P9610. Recognizing the role of genotype in susceptibility to infection, the hybrids were categorized as tolerant (DKC4590), sensitive (GKT376), or of undefined sensitivity (P9610). The results demonstrated a statistically significant impact (p = 0.05) of nitrogen fertilization and hybrid genotype on the incidence of fungal pathogens and mycotoxin levels. Specifically, higher nitrogen applications were correlated with increased severity of ear rot and greater mycotoxin contamination. However, the findings do not identify an optimal nitrogen rate, as nitrogen is crucial for maximizing yield and suggests the necessity for further studies comparing different hybrids and nitrogen rates. Importantly, understanding the sensitivity of commercial hybrids is critical for selecting those less prone to infection, as illustrated by significant reductions in mycotoxin levels across hybrids at varying nitrogen rates. This research indicates that appropriate hybrid selection can mitigate the impact of fungal ear rot and reduce mycotoxin contamination in maize kernels.