Outcrossing rates of barley landraces from Syria

Diversity levels in populations of barley landraces may be influenced by va rying levels of natural outcrossing caused by environmental conditions, Out crossing was studied in 10 accessions of the barley landrace Arabi Aswad fr om different environments in Syria. Electrophoretic variation at two codomi nant isoenzymes (Est1 and Est2) in six seeds of 50 families per population were analysed and multilocus outcrossing rates calculated. Results were cor related with interpolated environmental conditions. Outcrossing was, on ave rage, 1.7% and not significantly different from the outcrossing rate of wil d barley. A significant increase of outcrossing was observed with increasin g inter-annual variation in rainfall and decreasing minimum temperatures of the coldest month.