Abstract
Tobacco callus tissues infected with potato virus X (PVX), potato virus Y (PVY) or cucumber mosaic virus (CMV), tomato callus tissue infected with tobacco mosaic virus (TMV) or potato callus tissue infected with PVX were established respectively from the stems of inoculated plants. These tissues were successively transferred under the suitable conditions for proliferating either compact tissue or soft tissue, and the virus concentrations in the tissues were periodically assayed. In all the host-virus combinations tested, virus concentration in callus tissues rapidly decreased under the conditions of producing friable callus. Generally, the virus concentration was maintained at high level in compact callus. However, CMV in tobacco callus tissue and TMV in tomato callus tissue decreased rapidly even under the conditions to grow compact callus.
