Infectivity of Rice Viruses to the Varieties Resistant to Rice Stripe Virus

Rice varieties “Musashi-kogane”, “Tamaminori” and “Tamahonami” which have St2igene for resistance to rice stripe virus (RSV), showed resistance to RSV infection, but no resistance to virus multiplication. Furthermore, the vector Laodelphax striatellus acquired the virus readily on infected “Musashi-kogane” plants as did on susceptible “Nipponbare” plants. Sharp decline in the percentage of viruliferous insects in the overwintering population with the increase in the percentage areas planted with RSV-resistant varieties can be explained by the decrease of virus source plants for the secondary infection. The three RSV-resistant varieties did not show resistance to infection and multiplication of rice black-streaked dwarf virus (RBSDV) and rice dwarf virus (RDV). “Musashi-kogane” as well as “Nipponbare” served as the source of the three viruses for the transmission by their vectors.