Abstract

Medics are annual forages very interesting in pastures of Mediterranean and steppes rangelands. Such as other leguminous, they are subject to dormancy which delay and reduce germination. The response of these species (Medicago polymorpha, Medicago intertexta, Medicago ciliaris, Medicago truncatula, Medicago muricoleptis) to mechanical, physical and chemical scarification, applied for break dormancy, had been studied. Germination is almost full (reaching 100%) is fast (24 h) after scarification with sand-paper, which demonstrates that dormancy is exclusively imposed by teguments of the grain. Soaking in boiled water (20 s by population), passing through sulphuric acid during 5 min and 180 mn, passing in freezer and in refrigerator (respectively 2 h and 5 days), in drying oven at 115°C during 20 mn eliminates partially dormancy. However, passing through ovine digestive tract followed by germination test possesses the same effect as the witness. In exposure in ultra-low temperature at 196°C (liquid nitrogen) during 25 mn improves germination and grains germination speed to all quoted species which is comparable to scarified grains results by sand-paper. 

Keys words: Scarification, medics, populations, germination, dormancy.