Comparative study of seed vigor test in Medicago sativa

Seed vigor of 10 seed samples in Medicago sativa was determined by standard germination test, just germination test, cold germination test, and electrical conductivity test. We found that the 10 seed samples fell into three classification levels based on germination percentage and vigor index in the standard germination test. Under the just germination test, the 10 seed samples could be classified into 6 different levels based on radicle emergence with count time from 24 to 28 h after the beginning of incubation. Under the cold germination test, the seed samples could also be classified into 6 different levels based on vigor index and germination potential. Under the electrical conductivity test, the seed samples could be classified into 7 different levels. Thus, the electrical conductivity test was the most sensitive method for M. sativa seed vigor evaluation, followed by just germination test and cold germination test. The standard germination test was not suitable for seed vigor evaluation.