determination of trichothecene chemotypes and analysis population structure of fusarium graminearum isolates in golestan provience

fusarium head blight (fhb) or wheat scab is one of the destructive diseases that cause considerable loss in grain quality in cereal cultivated around the worldwide due to the production of trichotecen mycotoxin in the panicle. type b trichothecenes including nivalenol (niv), deoxynivalenol (don), 3-acetyl deoxynivalenol (3-acdon) and 15-deoxynivalenol (15-acdon) are considered to be major toxins produced by fusarium graminearum isolates. to determinate the trichothecene chemotyping among f. graminearum isolates, sampling was performed during 2009-2010 in different wheat fields in golestan province at the time of ear formation and revolution. after identification of isolates using morphological criteria, a number of 100 isolates were confirmed using species-specific primers (fg16f/fg16r) as f. graminearum species. in these isolates, the presence of the responsible gene for trichothecene (tri7) was detected by using pcr and species-specific primers (tri7f/tri7r). among the studied isolates in sampling area, a number of 72 isolates were identified as niv producing type and 28 isolates as don producing type. among the studied isolates, two populations as 7c1 and 6a5 were identified, which 7c1 (strain 7) population showed the highest distribution.