Improving Germination Rate of Medicago Scutellata and Medicago Rigidula as Affected by Seed-Coat Dormancy Breaking Techniques

Medicago scutellata and Medicago rigidula are two species of lucerne. As other legumes these exhibit dormancy, which delays and reduces germination. The germination response of these species to mechanical, physical and chemical scarification, applied for overcoming dormancy, has been studied. The almost full and rapid germination achieved by hand scarification with sandpaper, demonstrated that dormancy was exclusively imposed by 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 final germination and germination rate in seeds of M. scutellata. After 10 days of freezing the germination rate increased by 90%. Keeping seeds on surface run off also had a great result. After 7 days germination rate in seed of M. scutellata became 90%. Chemical scarification with sodium hypochlorite was also effective in reducing hardseededness at the lowest concentration (2%) for the shortest time (2 min) in seeds of M. rigidula.