Energy and dose effects of proton irradiation on soybean mutagenesis

To identify mutation inducing effects and parameters for irradiation treatment, three energy (3.0, 5.0 and 7.0 MeV) and four integral fluxes levels (1x108, 1x109, 1x10-10 and 1x1011H+/cm2) of proton beam were applied to irradiate the dry seeds of soybean [Glycine max (L.) M err.] cv. Suinong 14. The results showed that various mutations could be induced. Seed germination was not affected in the current experiment, whereas some other traits of the progenies were influenced, i. e., the height of M1 plants was significantly increased, and mutants including early-maturing, etiolated, sterile types were found in M2 plants. Total mutant frequency was 6.81% and it increased with the increment of the fluence level but not the energy level. Mutant percentage of the M2 plants derived from the treatment of 3.0MeV, 1x1011 H+/cm2 was 8.26%, the highest among the 13 treatments. Mutation types varied according to the energy and fluency levels. Early-maturing mutants were preferentially achieved when irradiated with 1x1010 or 1x1011 H+/cm2 integral flux or with 5.0MeV proton beam, etiolated and sterile mutants were frequently obtained when treated with 1x109 H+/cm2 or 1x1010 H+/cm2 irradiation. When the seeds were irradiated with the energy of 3.0MeV or 7.0MeV, more sterile mutants and etiolated mutants were obtained than in other treatments. It was drawn that proton beam as a new mutagen can be used in soybean breeding. (authors)