Intenzitet zaraze aspergilozne truleži klipa na hibridima kukuruza

Aflatoxin is a naturally occurring toxin produced by the fungus Aspergillus flavus. It is the most economically important mycotoxin in the world with proven toxic, mutagenic, teratogenic and carcinogenic effects on human and animal health. Preventive measures such as irrigation and planting dates can minimize aflatoxin contamination most years. However, no control strategy is completely effective, when environmental conditions are extremely favorable for growth of the fungus. The most effective aflatoxin control method is growing maize hybrids with genetic resistance to aflatoxin contamination. The aim of this research was to evaluate sensitivity of different maize hybrids to A. flavus infection and aflatoxin accumulation. Trial was set up in Sombor (Serbia). Fifty maize hybrids belonging to different FAO maturity groups were evaluated for sensitivity to ear rot and aflatoxin acummulation during 2016 in field trials with artificial inoculations using colonized tootpicks method. Based on these results, 20 hybrids were selected for the subsequent field experiments in early and late sowing dates. Two toxigenic isolates of A. flavus were used for artificial inoculations. The isolates were obtained from maize seeds originating from locality Bečej (Serbia). Mycotoxin production potential of the isolates was confirmed by rapid screening of aflatoxin biosynthesis genes - Cluster Amplification Patterns (CAPs) analysis. The ears were visually rated using a scale of 1 (complete absence of symptoms) to 7 (76-100% infected kernels). Aflatoxin B1 analysis was preformed by ELISA test. Results of this research indicate existance of significant differences in maize hybrids suspectibility to Aspergillus ear rot. Aflatoxin B1 concentration in grain differed significantly among hybrids. Based on the comparison of the range of symptoms and aflatoxin levels, it can be concluded that there is no correlation between visual rating and aflatoxin contamination. Therefore, visual rating of the hybrids is not enough to estimate food or feed safety. Different hybrids responded differently depending on the sowing date. Some hybrids were more susceptible to aflatoxin production in the earlier sowing dates, while others were more susceptible in the later sowing dates. In 2016, a significant negative correlation between yield and aflatoxin levels was observed, whereas in 2017 and 2018, correlation between observed variables was not significant. Maize hybrids that had low concentrations of aflatoxin may have internal or external kernel characteristics that have not been identified in hybrids previously reported to be resistant to A. flavus.