Abstract

Chickpea (Cicer arietinum L.) is one of the major pulse crops grown in India and other semi-arid regions of the world. Chickpea is reported to be affected by more than 52 pathogens (Nene et al., 1984). Among these, Fusarium oxysporum Schl. emend Snyd. Hans. f. sp. ciceri (Padwick) Snyd. and Hans, is a wide spread soil borne disease and is reported from many parts of India with intensity ranging from 10 to 100 per cent (Singh et al., 1986). The chickpea varieties resistant to Fusarium wilt is now becoming susceptible. It is, therefore, necessary to see the pathogenic variability so as to find out strategies for management of Fusarium wilt. Chickpea plants infected with Fusarium wilt were collected from 66 locations in 19 districts of Maharashtra at flowering to pod formation stage. Isolations from infected roots were made on potato dextrose agar. The isolates of Fusarium spp. were identified (Booth, 1971; Padwick, 1940). The isolates were categorized into different groups based on morphological, cultural characters and pathogenecity. Variations in the growth of mycelium, colour / pigmentation of mycelium and sporulation among the isolates were recorded by growing on agar medium (Om Gupta et al., 1986). The size of micro and macro conidia were measured with the help of binocular. Pathogenecity test on chickpea cultivar JG 62 a highly susceptible to Fusarium wilt was conducted by adapting pot culture technique (Hawre and Nene, 1982). For this purpose, the Fusarium isolates were mass multiplied on sterilized crushed cotton seed separately which was then mixed in the sterilized soil (soil + FYM, 3:1) at the rate of 1 kg Fusarium inoculum per 10 kg of sterilized soil. It was kept for 15 days so as to multiply. Water was given as and when required. The earthen pots of 10 cm diameter were filled with this wilt sick soil as per the isolates. The seeds of highly susceptible variety of chickpea i.e. JG 62 was sown in the pots. Pot as well as water culture technique (Nene et al., 1981, Cabrera, 1985) were adopted for identification of highly pathogenic isolates of Fusarium oxysporum f. sp. ciceri. The experiment was undertaken in completely randomized block design with five replications. The observation on wilt incidence was recorded at 30, 45 and 60 days after sowing in pot. The soil temperature and soil moisture prevailed during experimentation were in the range of 22-27oC and 12.5-20% respectively

Keywords: Fusarium spp, Pathogens