Growth and biological responses of soybean cultivars to gamma-ray and electron beam irradiation

Purpose Plant mutation breeding is an alternative approach that employs physical or chemical mutagens to develop new crop cultivars, in contrast to traditional hybridization and selection. For effective use of ionizing radiation, which induces a high mutation frequency, it is crucial to assess the mutagenic response of the target crop. This study aimed to evaluate the mutagenic response of nine soybean cultivars to different types and doses of ionizing radiation, focusing on plant growth traits and biological indicators, such as antioxidant enzyme activities and lipid peroxidation.Materials and methods In this study, we assessed nine soybean cultivars exposed to varying doses of ionizing radiation (gamma rays and electron beams), determining the lethal dose 50 (LD50) for survival rate and reduction dose 50 (RD50) for shoot growth reduction. We also evaluated biological responses, including malondialdehyde (MDA) content and the activities of three antioxidant enzymes: ascorbate peroxidase (APX), superoxide dismutase (SOD), and peroxidase (POD).Results The average LD50 and RD50 were 248 Gy and 178 Gy for gamma rays and 359 Gy and 321 Gy for electron beams, respectively. At doses near the LD50, MDA content showed a decreasing trend under both radiation types. Conversely, the activities of the three antioxidant enzymes generally decreased under gamma rays but increased under electron beams.Conclusions These findings demonstrate distinct growth and biological responses to gamma rays and electron beams, suggesting that the choice of radiation type and dose should be tailored to breeding objectives. This provides a practical basis for using electron beams as an alternative to gamma rays in soybean mutation breeding.