Germination Strategies of Some Accessions of Allium roseum L. Collected from Different Bioclimatic Areas of Southern Tunisia

This study deals with the germination and emergence behaviours of seeds and bulbs of four different accessions of Allium roseum L., a typically Mediterranean species considered as potential condiment with good flavour. Experiments were conducted both in laboratory and in field and several parameters were monitored in order to assess and compare the germination behaviour of four accessions of Allium roseum collected from four sites located along and aridity gradient in Southern Tunisia. The main achieved results show that the germination capacity of bulbs of the species is very low and does not exceed 30% for all studied accessions. The variation of seedlings emergence in the field constitutes an adaptation indicator of these accessions to aridity and drought confirmed by the presence of a high interaction between the reproduction mode and the environmental conditions. The accessions of the septentrional zones tend to be regenerated by an asexual multiplication (bulbs) whereas, those coming from the meridional (drier) zones tend to be regenerated by the sexual way (seeds). Survival of Allium roseum seedlings in Tunisian arid regions counts, therefore, on a sexual propagation much more than on a vegetative propagation.