Abstract
Male sterility was induced in sugar beet plants by cooling treatment at the early bud stage. The percentage of male sterile flowers was higher the longer the cooling treatment and lower the temperature from 5°C to 3°C. Complete male sterility was induced by the treatment at 3°C for 50 days or 5°C for 70 days. Microscopic observations confirmed that the microspores and tapetum cells were more sensitive to cool temperature than somatic cells within a sugar beet anther. Female organs in the male sterile plants under cooling were not fatally injured and they could produce hybrid seeds by crossing with normal pollen. These results indicated that cooling treatment, which induced male sterility in sugar beet plants, was applicable as a method of castration in the breeding system.
