COMPARATIVE SUSCEPTIBILITY OF SOME COMMERCIAL POTATO CULTIVARS TO FUSARIUM SAMBUCINUM AND F. SOLANI ISOLATES CAUSING TUBER DRY ROT

Fusarium dry rot is one of the most important diseases of potato (Solanum tuberosum L.), affecting the tubers in storage and the seed pieces after planting. Fusarium sambucinum and F. solani are common pathogens causing dry rot of stored tubers in temperate areas. In this study, infection of F. sambucinum and F. solani on tissue discs prepared from tubers of potato varieties that are susceptible or moderately resistant to this disease was studied. Tubers were wounded, inoculated, incubated at 15-20 °C for 5 weeks and the size of the rot was assessed. All isolates were found pathogenic to potato tubers and differed in pathogenicity. Obtained results revealed that Fusarium isolates showed variable aggressivity upon the 17 tested potato cultivars. Furthermore, no cultivars were found to be completely resistant to the whole Fusarium isolates, and only one cultivar showed a lesser susceptibility to pathogen. This cultivar was Broke®. Moreover, F. sambucinum isolates were detected as more aggressive pathogens than F. solani in all cultivars. Additionally, one out of three isolates of F. sambucinum was more aggressive than the others. All isolates used in this study were identified both based on colony and conodial morphology and also confirmed by molecular methods