Identification of Tea seed mycoflora and pathogenicity of Rhizoctonia solani

Presence of seed borne fungal pathogens in seeds of seven different commercial cultivars of tea plants of northeast India was studied. Fifteen different fungi were found to be associated with the seeds of tea plants externally. Internally, 11 fungi were found to be associated with the seeds. Rhizoctonia solani, five species of Aspergillus and two species of Rhizopus were found to be associated with the cotyledons of seven different tea seed varieties. Curvularia lunata, Fusarium sp., Alternaria sp., Botryodiplodia sp., Penicillium sp., Trichoderma pseudokoningii and a sterile fungus were also found to be associated with the seeds. Reduced germination percentage was observed in fungi-infested seed lots. Pathogenicity of selected fungi, isolated from the seeds was tested in tea seedlings of seven different varieties. All the seven varieties except TS-449 were found susceptible to Rhizoctonia solani only. Six varieties (TS-520, TS-462, TS-463, T-464, TS-491 & TS506) showed more than 87% disease severity when inoculated by R.solani. TS-449 showed about 49% disease severity when artificially infected by the pathogen.