Abstract
Seed infection could be induced by inoculating various parts of tomato plant with tomato canker bacteria (Corynebacterium michiganense). Especially, spray inoculation to flowers and needle prick inoculation to pedicel-tips showed high percentages. Spray inoculation to flowers gave rise to various degrees of seed infection in each tomato fruit. Generally, bacterial population and percent of infected seeds were high in tomato fruits inoculated at upper parts of plant. Bacterial population per seed and percent infected seeds were more constant in fruits inoculated by both the spray to flowers and needle prick to pedicel-tips than those inoculated by a single spray to flowers. Systemic infection of seeds was investigated with surface sterilized seeds. The results somewhat varied due to the method of surface sterilization, but evident systemic infection was observed in seeds obtained by flower inoculation and flower + pedicel-tip inoculation. When flowers were inoculated by spray, pathogenic bacteria seemed to invade seed through calyx scar and vascular bundle of fruits. Infection through this route was suggested to occur in field when the disease became epidemic.
