Abstract
Rice stripe disease is one of the viral diseases caused by Rice stripe virus (RSV), and can be controlled effectively by using resistant cultivars. The resistance gene introduced into those rice cultivars is Stvb-i derived from an indica rice cultivar "Modan". In order to understand the mechanism of the stripe resistance, infection of RSV and disease symptoms were examined in detail in rice resistant cultivars harboring the Stvb-i gene, “St. No. 1” and “Tsukinohikari”. Several tens of percent of resistant rice plants were infected with RSV, but not all the infected rice plants showed disease symptoms. The concentration of RSV was low and the viral spread to the upper leaves was suppressed in initial stage of RSV infection as compared to the susceptible rice. Taken together with information on RSV infection in the susceptible rice reported by other researchers, the results in this study suggested a quantitative effect of Stvb-i gene to viral infection and propagation in and around the apical meristem in the initial stage of RSV infection.
