Molecular diversity of native Trichoderma isolates against Fusarium oxysporum f. sp. lycopersici (Sacc.). A casual agent of Fusarium wilt in tomato (Lycopersicon esculentum Mill.)

Fusarium wilt in tomato caused by Fusarium oxysporum is the one of the problematic diseases. In this study, 12 native Trichoderma isolates were isolated from different land use types in Rayalaseema region of Andhrapradesh, India and were tested for antagonistic activity against F. oxysporum using dual culture method; the maximum inhibition occurred in WT2 (78.4%) compared to the control. Molecular characterisation using random amplified polymorphic DNA (RAPD) technique reported 91.8% polymorphism among 12 isolates of Trichoderma. Internal transcribed spacer (ITS) region of rDNA amplification with genus-specific ITS1 and ITS4 universal primers produced amplicon size from 569 bp in all the isolates. The study resulted in identification of good competitive Trichoderma isolates against F. oxysporum. A relationship was found between the polymorphism showed by the Trichoderma isolates and their hardness to F. oxysporum during antagonism. Also, exhibition of sufficient genetic polymorphism aids further exploitat...