Rakesh KumarPavitra P. Yaranal2022-12-192022-12-192021-09https://krishikosh.egranth.ac.in/handle/1/5810190666The present study entitled, ―Screening and evaluation of Arbuscular mycorrhiza on management of damping-off of onion incited by Fusarium sp.‖ was conducted under screen house conditions to study the role of mycorrhiza on growth and mycorrhizal parameters, biochemical constituents and influence on rhizosphere population of different microbes and to work out the integrated management of damping-off incited by Fusarium oxysporum. The pathogen is a soil inhabitant, facultative parasite and having wide host range. Fusarium oxysporum causes pre-emergence and post-emergence damping-off. Pathogenicity of Fusarium oxysporum was tested under screen house conditions. Maximum growth (plant height, root length, bulb weight), mycorrhizal parameters (per cent root colonization and sporocarp number per 100g of soil), SPAD-chlorophyll, biochemical constituents (total phenols, P content in roots) were observed in the onion plants inoculated with Glomus mosseae. All the AM fungi used viz., Glomus hoi, Glomus fasciculatum, Glomus intraradices and Glomus mosseae had positive influence on population of azotobacter, actinomycetes and bacteria, while significantly reduced the population of fungi compared to control. Maximum disease control (92.5%) was observed in seed treatment with Thiram @ 2g/kg of seeds. Among the biologicals, maximum disease control (81.25%) was observed in treatment with combined use of Glomus mosseae, Trichoderma harzianum and Pseudomonas fluorescens. Mycorrhiza was comparatively effective in managing the disease with a disease control of 48.75-70 per cent when inoculated alone or in combination with other treatments. Suitable symbiont for a host can improve plant growth and provide protection against diseases. The application of arbuscular mycorrhizal fungi in our study reflected a significant growth improvement of onion and comparable level of protection against the damping-off pathogen.EnglishThesis