Legume Research - An International Journal

Medicago scuteUata, Medicago rigidula and Medicago polymorpha are all lucem species. These are annual forage legumes of specific interest to agriculture in Mediterranean pasture. As with other legumes these have a state of seed dormancy, which delays and reduces germination. This research studied germination of these plants in response to mechanical, physical and chemical scarification to break dormancy. The rapid germination in almost all the seeds in the test was achieved from hand scarification with sandpaper, and this demonstrated that dormancy was exclusively imposed by the seed coat (hardseededness). Soaking in hot water partially removed coat-imposed dormancy in these species, but in M. scutellata even after 2 min at 100°C 97.9% of seeds still remained hard. Low temperature by keeping in refrigerator was also effective in stimulating final germination and a good rate of germination in seeds of M. scuteUata and M. polymorpha. After 10 days freezing the germination rate increased by 90%. There was also a good result from keeping seeds on surface run off, after 7 days there was 90% germination rate in seeds of M. scutellata. Chemical scarification with sodium hypochlorite was also used effectively to reduce hardseededness at the lowest concentration (2%) and the shortest time (2 min) in seeds of M. rigidula.