Fait, A., Department of Plant Science, Weizmann Institute of Science, 76100 Rehovot, Israel
Barazani, O., Department of Plant Sciences, G.S. Wise Faculty of Life Sciences, Tel Aviv University, 69978 Tel Aviv, Israel
Diemenstein, S., Department of Plant Sciences, G.S. Wise Faculty of Life Sciences, Tel Aviv University, 69978 Tel Aviv, Israel
Friedman, J., Department of Plant Sciences, G.S. Wise Faculty of Life Sciences, Tel Aviv University, 69978 Tel Aviv, Israel
Dudai, N., Aromatic, Medicinal and Spice Crops Unit, Newe Ya'ar Research Center, Agricultural Research Organization, P.O. Box 1021, 30095 Ramat Yishay, Israel
Putievsky, E., Aromatic, Medicinal and Spice Crops Unit, Newe Ya'ar Research Center, Agricultural Research Organization, P.O. Box 1021, 30095 Ramat Yishay, Israel

Foeniculum vulgare Mill. (Apiaceae) is a perennial hemicryptophyte native of the Mediterranean basin. In Israel, natural populations are distributed across different habitats and phytogeographical territories. To evaluate the occurrence of intra-specific adaptive traits, we studied the germination of mericarps, collected along a rainfall/altitude gradient, in response to constant and alternating temperatures. Germination response to the different temperature regimes was population specific (p<0.OO1), either when expressed as final percentage of germination (%G) or as germination rate (G50 and probability density functions). Southern-distributed populations exhibited higher %G as compared to northern ones under all temperature regimes. This in spite of the overall 50% decrease in %G at warmer constant and alternating temperatures that characterized the first. Temperature fluctuations prolonged the germination period of all populations by two to seven days, as compared to constant temperatures (7-13 days period), and populations responded differently to different fluctuation's factors, e.g. temperature amplitude, minimum andlor maximum temperature. Significant associations between germination (%G) and environmental variables was found e.g., January temp. (r= 0.62 to 0.70), rainfall (r= -0.58 to -0.84) and altitude (r= Ca. -0.7). Weight of mericarp varied significantly (p