Fungi of the Fusarium genus in the grains of conventional hybrids and transgenic Bt-hybrids of maize (Zea mays L.) in the Czech Republic

Abstract

Fungi of the Fusarium genus, the agent of ear rot in maize, not only causes decrease in yields but also negatively affects grain quality and, in relation to mycotoxins production, the health of humans and animals. This study focuses on determining the species range of Fusarium fungi in naturally infected stands of conventional hybrids and transgenic Bt-hybrids of maize in the Czech Republic during 2008 and 2009. Individual species of the Fusarium genus were determined on the basis of morphological characteristics and using polymerase chain reaction. Ten mycotoxigenic species were identified in hybrid maize grains: F. subglutinans (40.4%), F. graminearum (19.8%), F. verticillioides (18.2%), F. poae (9.3%), F. proliferatum (4.0%), F. avenaceum (3.8%), F. oxysporum (1.7%), F. sporotrichioides (1.3%), F. sambucinum (1.3%) and F. culmorum (0.2%). The species F. subglutinans, F. graminearum and F. verticillioides were dominant in both years. The frequency of individual Fusarium species did not significantly differ between conventional and transgenic Bt-hybrids. Differences in species representation were determined between individual years and sites. The hypothesized markedly lower infection of individual Bt-hybrids with fungi of the Fusarium genus was not statistically significant, although most Bt-hybrids did demonstrate lower infection without that being statistically significant. The average level of infection by the Fusarium genus in 2008 was 13.2% for grains of conventional hybrids and 6.6% for Bt-hybrids (50% lower). In 2009, the average infection level was 13.6% for conventional hybrids and 12.6% for Bt-hybrids (7.4% lower). The average infection level for grains of Bt-hybrids by the species F. subglutinans, F. graminearum and F. proliferatum was lower than that for grains of conventional hybrids in both years.