Influence of Fusarium spp. Inoculation Dose Simulating Pathogen Pressure on Grain Production Parameters of Zea mays L.

Abstract
Several fungi species from genus Fusarium can infect maize crop and cause seedling blight, root rot, stalk rot, cob and ear rot. Maize yield and grain quality are negatively affected by the disease, while mycotoxins accumulating in grains represent a serious threat to human and animal health. In this research two maize hybrids were subject to artificial infection in field with Fusarium spp. suspension at three incremental dose levels simulating increasing pathogen pressure. Results indicated that earlier maturing hybrid (‘Turda 248’ – FAO 300 maturity group) following artificial infection displayed lower infection index of ears (up to 15.33%) while the later-maturing hybrid (‘Turda 332’ – FAO 380 maturity group) displayed higher infection levels of up to 30.87%. Uninoculated controls presented infection index of ears below 2% for both hybrids. For the hybrid ‘Turda 248’ the highest pathogen pressure (inoculation dose 12 mL/ear) caused 23.10% yield decrease relative to control, while same dose for the hybrid ‘Turda 332’ caused 21.20% yield decrease relative to control. Once with increased inoculation dose the grain quality parameters displayed changes. The observed trend was an increasing protein content and decreasing starch content once with increased pathogen pressure. Identification of resistant genotypes and study of the climatic factors that undergo disease development remain important research approaches for efficient control of the pathogen populations in agroecosystems.