Dry storage temperatures, duration, and salt concentrations affect germination of local and edaphic ecotypes of Hordeum spontaneum (Poaceae) from Israel

Hordeum spontaneum, the ancestor of cultivated barley, is mainly distribute d in the Mediterranean zone of the Near East as well as in the Irano-Turani an steppes arid Saharo-Arabian region; these areas receive unpredictable sm all amounts and distribution of rain followed by long, hot and dry summers. Caryopses of seven local ecotypes of H. spontaneum were collected in Israe l from natural populations near Sede Boker, Neve Yaar, Tabigha and Mount He rmon. Three generations of these ecotypes were grown in natural conditions at Sede Boker with additional irrigation. The germination of caryopses of t he third generation was tested. Due to the self pollination and atelechoric system of seed dispersal of this species, genetic ecophysiological diversi ty of afterripening and salt tolerance was found between the ecotypes origi nating from different areas, even within local populations and patches of p lants that grew on different types or depths of soil at a distance of only a few meters from each other. Afterripening is important to prevent the car yopses from germinating shortly after maturation after a late rain at the b eginning of the dry summer. Germination of the different ecotypes is regula ted by temperature and length of post-maturation dry storage, as well as te mperatures during wetting, and salinity. (C) 1999 The Linnean Society of Lo ndon.