MORPHOLOGICAL AND PHYSIOLOGICAL VARIATION OF FUSARIUM OXYSPORUM F. SP. CICERI ISOLATES CAUSING WILT DISEASE IN CHICKPEA

Abstract

A total of nine isolates of Fusarium oxysporum f. sp. ciceri infecting chickpea were collected from major chickpea growing areas of Bangladesh and were characterized in terms of cultural, morphological, physiological characteristics and pathogenicity. The isolates varied significantly in their cultural, morphological and physiological traits, i.e. colony color, shape, margin and texture; mycelial radial growth and spore production. Laboratory studies were conducted to study the effect of different culture media, pH and temperature levels on mycelial growth and sporulation of Fusarium oxysporum f. sp. ciceri. Mycelial radial growth and sporulation of F. oxysporum was maximum for all the isolates at 25 °C after seven days of inoculation, which was reduced drastically below 15°C and above 35 °C. No growth and sporulation was observed at 5 °C temperature for all the isolates. The most suitable pH level for growth and sporulation of the fungus was at pH 6.0. The fungus grew well on oat meal agar medium among seven culture media tested. No sporulation observed on WA medium. The highest number of macro spores (3.27 x 105 ml-1) and micro spores (4.06 x 105 ml-1) were produced PDA. Among the nine tested isolates, only one isolate (FOC-1) found to be highly virulent (HV) type on reaction on chickpea variety BARI Chola – 1.