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

Abstract

Hordeum spontaneum, the ancestor of cultivated barley, is mainly distributed in the Mediterranean zone of the Near East as well as in the Irano-Turanian steppes and Saharo-Arabian region; these areas receive unpredictable small amounts and distribution of rain followed by long, hot and dry summers. Caryopses of seven local ecotypes of H. spontaneum were collected in Israel from natural populations near Sede Boker, Neve Yaar, Tabigha and Mount Hermon. Three generations of these ecotypes were grown in natural conditions at Sede Boker with additional irrigation. The germination of caryopses of the third generation was tested. Due to the self pollination and atelechoric system of seed dispersal of this species, genetic ecophysiological diversity of afterripening and salt tolerance was found between the ecotypes originating from different areas, even within local populations and patches of plants 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 caryopses from germinating shortly after maturation after a late rain at the beginning of the dry summer. Germination of the different ecotypes is regulated by temperature and length of post-maturation dry storage, as well as temperatures during wetting, and salinity.