Several chemicals were evaluated for their efficacy to induce sterility in rice (Oryza sativa L., Yamabiko) in 1990. Two chemicals, kasugamycin and aminooxyacetic acid (AOA), indicated a remarkable effect to induce sterility in rice when treated at meiosis. In 1991, kasugamycin and AOA were applied to rice plants at two different growth stages to find the optimum application period and dosage for the induction of sterility. Kasugamycin affected sterility in rice only at meiosis, but AOA affected it from the panicle formation stage to meiosis at a low concentration of 100 mg/liter. Rice plants treated with kasugamycin were similar to control for the number of seeds, spike length, culm length and weight of ripe seeds, but rice plants treated with AOA were inferior to the control in these respects. Interaction between kasugamycin and the plant hormone for the restoration of fertility was shown in rice when alpha-naphthylacetic acid (NAA) was applied simultaneously with kasugamycin.
