Effect of two types of mutagens on seed germination and physiological characteristics of alfalfa

To explore the effects of two types of mutagens on seed germination and physiological characteristics of alfalfa (Medicago sativa) using Wega7F alfalfa seeds as test materials, this study analyzed seed germination, seedling growth, and physiological characteristics under mutagenic treatments with doses of 60Co-γ and ethyl methyl sulfonate (EMS). The results showed that the effects of 60Co-γ rays on germination percentage, germination index, and seedling growth varied with dose. A low dose (150 Gy) increased germination percentage, germination index, seedling growth, and plant height, whereas high doses (300 and 450 Gy) reduced germination rate, seedling growth, and plant height. However, treatments with EMS at different doses reduced germination rate, seedling growth, and plant height. The two mutagens increased the branch number of alfalfa. Plant biomass increased with the two mutagen treatments at lower doses. Chlorophyll content increased with 60Co-γ irradiation and 0.4% EMS treatment. The activities of superoxide dismutase (SOD), peroxidase (POD), and hydrogen peroxidase (CAT) were enhances under the two mutagenic treatments at different doses; the order of activity of the three enzymes was POD>CAT>SOD. The results of this study suggested that 60Co-γ at 150 Gy had significant influence on alfalfa yield and plant height; the application of alfalfa has been used to provide certain value. EMS treatments were more effective in increasing the potential for alfalfa branching, which is beneficial for improving the ornamental aspects of alfalfa.