Natural toxigenic fungal and mycotoxin occurrence in maize hybrids

The objective of the present study was to investigate the susceptibility of maize hybrids to the natural occurrence of toxigenic fungal species, in particular toxigenic Aspergillus and Fusarium species, and mycotoxins (aflatoxin B1 (AFB1), deoxynivalenol (DON) and total fumonisins B1, B2 and B3 (FBs)). Grain samples of six commercial maize hybrids (MAS 34.B – FAO 300, MAS 40.F, MAS 48.L, KWS Konfites and ZP 427 – FAO 400, and MAS 56.A – FAO 500) were collected at harvest in 2018. A total of seven fungal genera, Acremonium, Alternaria, Epicoccum, Fusarium, Nigrospora, Penicillium and Rhizopus, were identified of which only species from the genus Fusarium were present on maize grains of all hybrids tested. The incidence of Fusarium spp. was higher in the hybrids MAS 48.L (54.6%), and MAS 56.A (53.3%), compared to MAS 40.F (37.3%), KWS Konfites (28%), MAS 34.B (22.6%) and ZP 427 (12%) hybrids. Among the identified Fusarium species (F. graminearum, F. proliferatum, F. subglutinans and F. verticillioides), F. proliferatum was present in all hybrids, ranging from 9.3% (ZP 427) to 30.7% (MAS 48.L ), whereas F. subglutinans was present in two hybrids, MAS 40.F (16%) and MAS 56.A (9.3%). The incidence of F. graminearum ranged from 0% (KWS Konfites) to 9.3% (MAS 34.B), while the incidence of F. verticillioides ranged from 0% (MAS 34.B and ZP 427) to 21.3% (MAS 48.L). In the samples, Aspergillus species were not identified. The effect of maize hybrids was significant on the level of mycotoxins. MAS 34.B hybrid had a statistically significantly higher levels of AFB1 and DON than other hybrids. The FBs level was the highest in the hybrid MAS 34.B (1202 μg kg-1) and the lowest in the hybrid KWS Konfites (88.33 μg kg-1). However, the FBs level did not differ between hybrids MAS 34.B, MAS 40.F, and MAS 56.L, MAS 40.F, MAS 48.L, and MAS 56.A, and KWS Konfites and ZP 427. In all hybrids, AFB1, DON, and FBs levels were below the maximum permissible levels stipulated by the legislation of the European Union and the Republic of Serbia in unprocessed maize. The agro-ecological conditions in 2018 favored the development of Fusarium species on maize grains of the hybrids tested, especially fumonisin producing species.