Irradiation service for the vegetatively propagated crop breeding at the institute of radiation breeding

The entrusted irradiation for vegetatively propagating crops reached about 200 cases since 1962. As to the results, 109 cases which were able to be tracked by questionnaire and others were examined. When the number of cases for each crop was investigated, arbor crops and herbaceous crops were half and half, and in the arbor crops, fruit trees were overwhelmingly many, while in the herbaceous crops, potatoes were more than half, and the number of cases for rush also was many. As the rare examples, there were butterbur, medicinal plants and sugarcane. As the registered practical varieties, there were one case of rush and one case of Chinese mat grass, but in the arbor crops, there was none. The purpose has been mostly the breeding of new varieties, but there were the inactivation of viruses and the effect of insecticide. The aims of breeding have been early growth, high yield, disease resistance, dwarfness and so on. As the mutation actually obtained, the skin color of fruits, the flower color of rose and chrysanthemum, the short vines of potatoes, the quality of rush and so on. The clients were mostly public experiment stations. The method of irradiation and the problems for the future are reported. (Kako, I.)