The Resistances to Rice Stripe Virus and Small Brown Planthopper in Rice Variety, IR 50.

Abstract

Mechanism and inheritance of resistance to rice stripe virus (RSV) in several varieties were studied. It was apparent that Musashikogane and Minamihatamochi were highly resistant and IR 50 and TN I were moderately resistant to virus infection. IR 50 was found to be resistant to the small brown planthopper (SBPH) which was the vector of RSV. The inheritance of resistances to RSV and SBPH were studied by using the F3 and F6 generations of a cross of IR 50 with a susceptible variety, Reimei. The distribution of RSV and SBPH resistances at F3 and F6 were continuous and suggested a pluralgenes control of resistance. The F3 and F6 Iines were classified into groups of resistant (R), moderately resistant (M) and susceptible (S) to RSV infection and the SBPH resistance level of each group was evaluated. No significant difference was observed between the R and M+S groups of F3, however, the R group of F6 was significantly more resistant than the M and S groups. Thus an influence of SBPH resistance on the RSV infection of F6 was suspected. It was estimated that SBPH resistance was effective in reducing RSV infection, and the RSV resistance in IR 50 based on the resistances to SBPH and virus infection and they were controlled by pluralgenes.