1990 Volume 56 Issue 2 Pages 177-184
To clarify the cause of difference between soybean mosaic virus strains B (SMV-B) and D (SMV-D) in the ability of transmission through seeds, the mode of translocation, multiplication and inactivation of both SMV strains in a soybean was investigated. After soybean cultivar Hyuga was inoculated with each strain, virus concentration in the leaves and seeds was periodically assayed by bioassay and ELISA. When 3rd trifoliolate leaves were inoculated with two virus strains at V4 (4th node) stage, the concentration of SMV-D in the leaves upper than the inoculated leaves increased more vigorously and reached higher level than SMV-B on the 10th day after inoculation. After that, the concentration of both strains decreased with plant aging; that of SMV-D decreased more rapidly than SMV-B. On the 50th day after inoculation, both strains were faintly detected from the leaves lower than the inoculated leaves, and in these leaves also, decrease of SMV-D was faster than that of SMV-B. When inoculation was done to various leaves not extremely aged at different stages not later than R1 (beginning bloom stage), both SMV strains were readily translocated to the seeds set at the upper and lower nodes than the inoculated leaves. In conclusion, there was no significant difference of translocation patterns between two strains, but in every infected organ (leaf or seed) SMV-D disappeared more briefly than SMV-B.