Abstract
Heavy-ion beams are an effective mutagen for use in plant breeding and analyses of gene function. Heavy-ion beams have high linear energy transfer (LET) and thus they effectively induce DNA double-strand breaks. To rapidly evaluate effective LETs for inducing mutations, we investigated mutation frequencies in the M1 generation using the Arabidopsis heterozygous mutant of the ALBINO PALE GREEN 3 gene. Leaves of heterozygous plants in which intact alleles were mutated showed white sectors. We irradiated heterozygous plants with heavy-ion beams with LETs ranging from 22.5 to 61.5 keV µm－1 and doses ranging from 0 to 450 Gy. The results showed that the effect of LETs could be classified into three types: first, the LET of 22.5 keV µm－1 did not effectively induce mutations, regardless of the dose; second, LETs of 30.0 or 42.5 keV µm－1 were not effective at low doses (100–200 Gy) but were effective at 300 Gy; third, LETs of 50.0 or 61.5 keV µm－1 produced comparatively high mutation frequencies at all doses. Irradiation with 42.5–61.5 keV µm－1 reduced seed productivity at the dose providing the highest mutation frequencies (300 Gy). We concluded that an LET of 30.0 keV µm－1 was optimal for obtaining Arabidopsis thaliana mutants in the M2 generation.
