Abstract:

The aim of this study was to select an ideal alfalfa variety that could overwinter in Heilongjiang Province. Three cold-resistant mutants, lm1609, lm1625 and lm1704, were obtained from the second-generation population of ‘Longmu 806’ after magnetic field free space treatment, and their cold-resistant performance was identified by measuring germination index, wintering rate, yield characteristic index and root physiological and biochemical index. There was no significant difference in germination index between the three mutants and the control. The germination potential and simplified activity index of lm1609 were significantly higher than those of lm1625 and lm1704 (82.05% and 469.82, respectively) (P<0.05). The overwintering rate of the three mutants was significantly lower than that of the control group. There was no significant difference in plant height between mutants and control on June 6. With plant growth, lm1609 and lm1704 on July 6 and August 6 were significantly higher than those of lm1625 and control. The difference in fresh grass yield among the mutants lm1609, lm1625 and lm1704 was not significant, but significantly higher than that of the control (P<0.05). The root peroxidase and superoxide dismutase of the three alfalfa mutants were significantly higher than those of the control, and the highest POD and SOD of the mutants were 304.85 OD470/(min·g) and 208.41 U/g, respectively (P<0.05). lm1609 mutant was an ideal cold resistant mutant material that has high cold resistance and yield characteristics.

Key words: magnetic field free space, alfalfa, mutagenic mutant, cold resistant