Study On The Mutation Effect Of Four Mutagens For Chinese Fir(Cunninghamia Lanceolata [Lamb.] Hook)

To found optimization methods in Chinese fir mutation breeding and made new genotype for further study, the seeds of Chinese fir were mutagenized by four mutagens, including one physical mutagen (y-ray), and three chemical mutagens (EMS, SA and colchinine), meanwhile, we also treated the clones of Chinese fir with γ-ray.In our study, we found that 1) When the seeds were treated with60Co-y-ray, with the dose of y-ray increased, the growth of youngChinese fir plants became weaker, and the germination of seeds wasputted off; 2)In EMS treatments, with the density and the time of EMS increased, the growth of young Chinese fir plants bacme weaker; 3) In SA treatmentsboth the density and time had an inhibiting effect on the growth of young Chinese fir plants.The system of Chinese fir mutation breeding is established. 1)According to the LD50 and the growth of seedings, the optimum mutagen dosageor time of three mutation methods were confirmed:For 60Co-y-ray method,40-60Gy; the time of EMS mutation was 8h and the density was 0.3%; SA was 12h and 6mmol/L.2) According to the variation rates,0.9% colchicine solutionand 4 days treatment was the optimum combination, tetraploid cells were found in the mutagenic materials.3)The optimum dose of 60Co-y-ray was 5Gy. The DNA variation of the clones radiated by 60Co-y-ray have been tested by ISSR, which creates material for further study.More than 90000 mutagenized plants were afforested on about 467 units lands, and we found some potential mutagenic plants with variantphenotypes including dense lateral branchs, sparse lateral branchs, new buds colour abnormal needles colour abnormal, reproductive growth in advance and so on.This study have provided more selection for new material and varieties in Chinese fir breeding.