Author(s):

Lalngaihawmi and Ashok Bhattacharyya

Abstract: A total of 54 native rhizospheric microbes were screened under in vitro for their antagonistic effect against Fusarium oxysporum f. sp. cubense (Foc), the causal organism of Fusarium wilt of banana. The effect of all the rhizospheric microbes collected during the present investigation significantly differed in terms of inhibition of radial growth of Foc. After 120 hours of incubation, Trichoderma reesei (RMF-25) was found most promising as antagonist against Foc with 71.08 per cent inhibition of radial growth followed by T. reesei (RMF- 13) with 70.55 per cent and T. harzianum (RMF-28) with 70.15 per cent inhibition of radial growth of Foc. The three best promising Trichoderma spp. were further screened for their ability to produce secondary metabolites viz. volatile and non-volatile compounds. The results revealed that all the Trichoderma spp. significantly inhibited the test pathogen by production of toxic metabolites and diffusible non-volatile secondary metabolites. In the case of production f toxic volatile compounds, the per cent inhibition of radial growth of Foc was observed highest by T. reesei (RMF 25) with 40.52 per cent inhibition which is closely followed by T. reesei (RMF 13) with 40.14 per cent and T. harzianum (RMF 28) with 39.03 per cent inhibition. All the Trichoderma spp. were also found to produce diffusible non-volatile metabolites where T. reesei (RMF- 25) was found to be most promising with 35.96 per cent inhibition of radial growth followed by T. reesei (RMF- 13) with 35.22 per cent and T. harzianum (RMF- 28) with 34.72 per cent inhibition of radial growth of the test pathogen in vitro.

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