ارتباط بين نشانگرهاي RAPD و حساسيت پايه اي به تريفلوميزول در جدايه هاي فوزاريوم عامل پوسيدگي طوقه برنج

Relationship between RAPD markers and baseline sensitivity to triflumizole in Fusarium isolates, causal agents of rice bakanae disease and foot rot

Three species of Fusarium verticillioides, F. fujikuroi and F. proliferatum, have been considered as the causal agents of rice bakanae disease and foot rot in different regions. To detect resistance to new fungicide in fungal isolates of disease causal agent, identification of baseline sensitivity is necessary before its application in field level. Genetic variation has been identified as one of the major factors differing baseline sensitivity to fungicides. In this study, baseline sensitivity of 46 isolates to triflumizole was investigated in PSA medium amended with different concentrations of fungicide active ingredient, and EC50 and MIC of this fungicide were calculated for each isolate. Also 21 isolates, belong to 3 mating populations were selected for molecular studies using RAPD markers. The results showed that different isolates placed on 4 groups on the basis of overlapping 95% confidence limits for EC50 and only two isolates had less sensitivity to triflumizole. In constructed dendrogram by RAPD markers, isolates with higher EC50, the most and the least sensitive isolates showed more difference with others. Also F. fujikuroi isolates showed markedly difference based on MIC value. The observed differences among isolates using RAPD markers confirmed that differences in baseline sensitivity to triflumizole rooted in genetic variation.