Morphological and molecular characterization of Fusarium species causing root and crown rot of safflower

Safflower (Carthamus tinctorius) is an annual plant belonging to the family Asteraceae. The cultivation of safflower has gained increasing attention due to its valuable seed oil, vibrant flower color, and tolerance to drought and salinity.However, infections caused by Fusarium species pose a significant challenge worldwide. To investigate the morphological and molecular characteristics of Fusarium species associated with crown and root rot in safflower,samples were collected from infected crowns and roots across various cultivation areas in Isfahan Province. Based on morphological traits and molecular data obtained from sequencing the ITS-rDNA region and a portion of the TEF1gene, two Fusarium species—F.nygamai, and F. falciforme were identified among 36 isolates exhibiting symptoms of crown and root rot disease. Pathogenicity tests conducted under greenhouse conditions confirmed their pathogenicnature according to Koch’s postulates. Notably, this study represents the first report of F. nygamai and F. falciforme as causal agents of crown and root rot in safflower worldwide.