Effects of Carbon Ion Beam Irradiation on Phenotypic Variations and Biochemical Parameters in Early Generations of Soybean Plants

Understanding the characteristics of carbon ion beam irradiation-induced mutation is essential to its potential application in plant breeding. A carbon ion beam-mutagenized soybean population was generated from the newly released soybean variety Dongsheng 28, with irradiation dosages of 100 Gy, 120 Gy and 140 Gy. Many phenotypic variations and novel mutants with heritable tendencies including plant height mutants, sterile mutants, early mature mutants, rolled leaves and short petioles mutants, yield-related mutants and lodging-resistant mutants were identified. Diverse variations in seed size, seed protein and oil concentration were found. Increasing irradiation dosage from 100 Gy to 140 Gy increased leaf chlorophyll concentration in M 1 generation, but this effect was significantly reduced in M 2 generation. The activities of superoxide dismutase (SOD), peroxidase (POD) and malondialdehyde (MDA) concentration all showed wider variation in M 1 and M 2 generation, the only exception being that the MDA concentration was similar to the control in the M 2 generation. Overall, we suggest that treating soybean seeds with carbon ion beam irradiation at a dosage of 120 Gy (80 Mev/u) could be effective in soybean mutation breeding.