Mycotoxin contamination of winter wheat cultivars after infection with Fusarium culmorum

Fusarium head blight (FHB) severity of 10 winter wheat cultivars (Zitarka, Srpanjka, Super Zitarka, Barbara, Golubica, Janica, Panonka, Alka, Osk. 87/03, Osk. 266/03) and the accumulation of deoxynivalenol (DON) after artificial infection in field with a strain of F. culmorum have been investigated. The wheat heads (the plot size was 7.56 m2) were sprayed at mid-anthesis with a hand sprayer, assuring that all spikelets were exposed to the inoculum. Inoculated heads were covered with PVC bags for 24 hours to ensure high relative humidity. The evaluation of macroscopically visible infection on field was completed at milking stage, being evaluated from 0 to 5 according to the Tomasovic scale (1987). Based on the number of infected heads and on the disease intensity on each head, the disease index was calculated according to McKinney (1923). Upon harvesting, the samples were taken for the purpose of laboratory analyses (to obtain percentage and germination of infected grains) and the DON content analysis. The content of DON was determined by immunoaffinity column (DONPREP column ; R-BIOPHARM RHONE LTD) cleanup followed by high-performance liquid chromatography (IAC-HPLC). The disease index was between 17.27 and 36.47. The percentage of infected grains was between 40.83% and 60.17%. Of the total number of infected grains, percentage of grains that exhibited symptoms was from 44.38% to 56.89%. Germination of infected grains (either with or without symptoms) was very low, being from 14.75% and 24.50%. The DON content in the analysed samples was from 1.138 to 2.476 mg/kg. A good correlation between FHB disease index and DON contamination was observed when the regression analysis was performed on all tested cultivars with correlation coefficient r = 0.972. This result is in agreement with previous data indicating that the severity of FHB can be used as useful indicator of grain contamination by DON.