Association of Two Unknown Pythium spp. without Forming Sexual Structures on Root Rot of Hydroponically Grown Welsh onion

Aims: Aim of this study was to elucidate association Pythium isolates without forming sexual structures on root rot hydroponically grown Welsh onion, as well clarify their taxonomic positions.
 Place and Duration Study: Commercial hydroponic greenhouses in Hiroshima Prefecture, Prefectural Technology Research Institute, Osaka Metropolitan University, between March 2020 2021.
 Methodology: Total 2,966 Pythium-like organs were isolated from the plant roots during survey period. All didn’t form any organs, separated into three groups based colony patterns agar media such cornmeal agar. Among them, 236 equally selected each groups. Since two thought be first records 17 representative examined morphology, hyphal growth response temperatures sequences ribosomal internal transcribed spacer (ITS) regions mitochondrial COI. Inoculation tests performed onion seedlings under a condition by using one isolate group.
 Results: The identified Cluster B2a sp., B1d sp. Clade A ITS COI, respectively. belonged showed similar morphology other. confirmed that both cause 14 days after inoculation. stronger pathogenicity than A.
 Conclusion: present firstly demonstrated which don’t associate onion.