Characterization of Indian isolates of Fusarium oxysporum Schlecht. causing fenugreek wilt

Abstract

Fusarium oxysporum schlecht. is a soil borne fungus that causing wilt disease in fenugreek [Trigonella foenum-graecum L.]. Fenugreek plant showing typical wilt symptoms were collected from fifteen different locations of Saurashtra regions of Gujarat. Isolation from diseased roots portion of wilted plant were carried out which yielded species of Fusarium with different cultural and morphological characters on potato dextrose agar media. Koch’s postulates were performed by standard method for all fifteen isolates and they gave different response in form of varied disease incidence. On the basis of cultural, morphological, molecular characteristics and pathogenicity test, the fungus was confirmed as Fusarium oxysporum Schlecht. The pathogenic nature of fifteen isolates tested on fenugreek wilt susceptible cultivar Gujarat methi-2, three isolate (Thari, Balagam and Char) were found non pathogenic gave zero per cent disease incidence (PDI), while one isolate (Khadpipali) found highly pathogenic with 93.33 per cent PDI which was further used for molecular identification and screening of agro-chemicals. Study of cultural characters and conidial morphology of different isolates were carried out which showed variation in growth habit, pigmentation, sporulation, shape and size of macro and micro conidia, structure and size of chlamydospores, etc.