水稻의 受精卵 및 早期原胚의 放射線調査에 關한 硏究

Studies on the Irradiation of Early Proembryos of Rice

Early proembryos of various stages ranging from 5 to 29 hours after flowering were X-rayed to examine seed formation of irradiated flowers, survival and fertility of M₁, plant, mutation rate, occurrence of chimaera and segregation ratio of albino. Developing proembryos seemed to be more sensitive to high dose than the free nuclei endosperm tissue. Fertility of M₁ plant were higher as compared with that of seed irradiation. Mutation rate based on albino and xantha was 5.6%, rather lower that those of seed irradiation, but higher when considered in terms of dose given. Plant based chimaeras were observed at every stages of proembryo development except the irradiation of fertilized egg. Segregation ratio of albino in mutated panicles of chimaeric plants was 0.06, while that of non-chimaeric plant was 0.20. Occurrence of chimaera in the irradiation at the early stage of proembryo is considered not true chimaera but the excessive recessive deficit.