在日本农林水产省农业生物资源研究所放射线育种场,发现了一个对黑斑病抗性强的突变体,被称为“γ_1”。二十年来,在γ射线实验场每天用13—14伦琴的较弱的γ射线,对供试树照射20小时。“γ_1”是6株供试树中的一株。将这株树扦插,3年育成苗,经人工接种病源对感病速度和程度进行 At the radiation breeding farm of Japan’s Agriculture, Forestry and Fisheries Research Institute for Agricultural Biological Resources, a mutant with strong resistance to melasma was found, called γ_1. For two decades, the test tree was irradiated with weaker γ-rays of 13-14 Roentgen per day for 20 hours in a gamma-ray field. “Γ_1” is one of the six tested trees. The tree cuttings, 3-year-breeding, the pathogen of artificial inoculation on the speed and extent of susceptibility