Incubation of Puccinia horiana P. H. using chrysanthemum plants cultured in vitro

To propagate and maintain the pathogen, Puccinia horiana P. H. as the inocu lum of white rust, sterile chrysanthemum plants cultured in vitro were infe cted. 1. Chrysanthemum plants, growing in vitro, were infected with spores of Puc cinia horiana without cross contamination by fixing the sporulated leaf fro m an infected plant grown in a greenhouse above leaves of sterile receptor plants. 2. Puccinia horiana was subcultured by placing leaves with telia to the bac kside of the cap of glass culture box containing sterile chrysanthemum plan ts. 3. Puccinia horiana incubated on the plants can be preserved at low tempera ture for 4 months. 4. The pathogenicity of Puccinia horiana, subcultured on the plants grown i n vitro onto plants in a greenhouse, was maintained for at least 14 months after the primary incubation.