pathogenicity two fusarium species, casual agent of rice bakanae disease and foot rot in guilan province

gibberella fujikuroi the cause of rice bakanae disease and foot rot is one of the important seed-borne diseases in guilan province. three fusarium species including fusarium proliferatum, fusarium verticillioides and fusarium fujikuroi have been reported as the casual agents of rice bakanae disease from all over the world. these three species belonged to three mating population a, c and d that have previously been reported from guilan province (hosein nejad et al. 2008). these fusarium species makes symptoms on seedlings in nurseries and plants on the field. the study of pathogenicity of different isolates were done by collecting 42 isolates of infected samples from rice infected fields in guilan province due to 2012-2013. morphological identification of species carried out based on valid identification literatures (leslie & summerell 2006, gerlach & nirenberg 1982) and two species viz f. verticillioides and f. fujikuroi were identified. frequency of f. verticillioides and f. fujikuroi was 88.4 and 11.6 respectively. the plant stems were inoculated by spore suspension of pathogens with 106 conidia/ml on the sepidroud cultivar seedlings and percentage of death tillers was evaluated. the results showed that f. verticillioides isolates were more virulent than f. fujikuroi and cluster analysis of isolates from pathogenicity viewpoint, characterized four different groups. all isolates of f. verticillioides were in the group with high pathogenicity.