SPACE MUTAGENESIS IN OILSEED GENETIC IMPROVEMENT

摘要

In recent researches, purposely selected oilseed seeds were exposed to outer space by the media of recoverable artificial satellites or scientific experimental balloons. The recovered seeds were tested and the mutants identified. Our preliminary results had shown that outer space conditions could effectively induce some biological variations especially to double-low oilseed. Some mutants were steadily existed and even could transfer the mutated traits to their descendent populations. In double-low Brassica campestris line "DL9-279", plants with mutated branch site and branch number, pods number, pod length and 1000-seed weight were harvested from the treated population. Many of the yield-related mutant lines showed significant production-increasing potentials. Long-pod rapeseed mutant was luckily obtained and achieved further studies. It was proved to be stable and heritable. From its offspring, 11 newly bred lines were gained and provided to Preliminary Regional Test. Six of them produced high yields compared to the control. Three lines with the highest production got the yield increase to 34.94%, 27.165% and 21.38%, respectively. In double-low Brassica napus variety "698-141", space conditions also caused lots of biological mutations. Some of the mutated characters appeared in the treated generation (SP_1) and diverged in SP_2 and SP_3. In their SP_2 populations, 521 superior lines (mutated lines with fine qualities) were obtained; among which were 177 yellow-seed mutants. All these superior lines showed high yield potentials. The average yield of their SP_2 and SP_3 increased from 19.6% to 37.4%. Further studies had proved that yellow-seed character could transfer to its progenies but diverged to a large scale. There also were several mutant lines with different maturation stage from the balloon-carried treatment of canola variety "Zhongshuang No. 4", The inductive effect was not so good as the satellite-carried treatment, nevertheless. Rapeseed was considered to be resistant to radiation mutagenesis because of its chemical components. But in this research, numerous stable mutants were got in double-low varieties and some of them showed privilege in oilseed breeding program and genetic improvement. The relationship between the high frequent mutagenesis and the double-low qualities needed further studies.