Fusarium and deoxynivalenol contamination of durum wheat lines kernels

Abstract

Fusarium infection and deoxynivalenol (DON) contamination on the kernels of seven durum wheat lines (six domestic durum lines ZP 16, ZP 34, ZP 41, ZP 74, ZP 120, ZP DSP 66, and one international durum line Cimmyt 7817) during harvest in two growing seasons (2015- 2016) have estimated. Mycological methods were performed to determine the incidence of Fusarium spp., while the Enzyme-Linked Immunosorbent Assay (ELISA) was used to quantify the total level of DON. Analysis of data was done by statistical method ANOVA (analysis of variance). Tukey’s test was used to compare means at a significance level of 5%. Correlation analyses were performed by Pearson’s test. Based on morphological characteristics, four Fusarium species, F. graminearum, F. proliferatum, F. sporotrichioides, and F. verticillioides, were identified in 2015. A different structure of the Fusarium population, which in addition to F. graminearum, F. sporotrichioides and F. verticillioides, also consisted of F. poae, F. semitectum, and F. subglutinans, was identified in 2016. F. graminearum was the predominant species and the most common cause of Fusarium head blight (FHB) and the primary producer of DON. Other Fusarium spp. Were isolated sporadically and in a low incidence in the kernels. Fungal species from the genera Alternaria, Aspergillus, Chaetomium, Epicoccum, Nigrospora, and Penicillium have also been isolated. The incidence of F. graminearum and level of DON were significantly affected by the wheat genotypes and investigated years. However, obtained results for these parameters were negatively correlated. Thus, in 2015, the incidence of F. graminearum was significantly higher (75.86%) than in 2016 (63.43%), while the level of DON was significantly higher in 2016 (3.636 mg/kg) compared to 2015 (1.126 mg/kg). The highest and the lowest incidence of F. graminearum was on the kernels of line ZP DSP 66 (73%) and line ZP 34 (64.50%), respectively. The highest DON level was 3.854 mg/kg (line ZP 120), and the lowest was 1.658 mg/kg (line ZP 41). The mean DON level was 2.381 mg/kg for all tested treatments and was above the maximum limit of 1.750 mg/kg prescribed by the European Regulation 1881/2006/EC for unprocessed durum wheat, while the mean incidence of F. graminearum was 69.64%. Based on obtained results, tested durum wheat lines showed susceptibility to F. graminearum and as a consequence higher accumulation of mycotoxin DON. These results indicate the importance of using less susceptible or tolerant lines to the pathogens of FHB and DON accumulation in the selection programs of new durum wheat varieties.