Morphological and pathogenic variability of Fusarium oxysporum. f. sp. Lycopersici causing tomato wilt disease

Abstract

Tomato occupies a major position in the family Solanaceae and it is the highly consumable crop all over the world. Among the various diseases affecting tomato, wilt incited by Fusarium oxysporum f. sp. Lycopersici is the one of the economically important disease which causes yield loss upto 50%. In the present study, survey was undertaken in Madurai districts of Tamil Nadu for the collection of Fusarium isolates. The Fusarium wilt disease incidence was noticed with the range of 23.3-42.2 per cent in various tomato cultivars. Ten isolates of Fusarium were isolated from symptomatic tissues and maintained in pure culture. All the 10 isolates produced dull to deep white colour colony with a diameter ranged from 80-90 mm in PDA medium. The pathogenicity test using the cultivar PKM-1was carried out and by sand maize agar medium revealed that, the isolate FO (Maa-5) was more virulent followed by FO (Mel-7) and FO (Kar-2) which was found to be least virulent. The morphological and pathogenic variability among the Fusarium isolates were observed within the close proximity.