Wild oats (Avena fatua L.) is a world-wide invasive species that competes strongly with small grain cereal crops, causing significant yield losses when left unmanaged. It is a summer annual weed in Northern Europe, while in Mediterranean climates it behaves as a winter annual weed. With a climate change this behavior can change. A joint experiment with populations of A. fatua is being conducted to study the emergence and phenological developments of this weed at several locations in Europe and the Middle East: Czech Republic, Denmark, Germany, Greece, Iran (2 sites), Latvia, Poland (3 sites), Spain and Turkey. Two common populations, the first one harvested in Latvia in a cereal field and the second in Spain from road sides, were established in all locations plus one-two local populations at some sites. After more specific investigations the Spanish common population was A. barbata, a wild oat species which is more important in road-sides than in cereal fields. The seeds will be characterised regarding germination percentage at various controlled climatic conditions. The local populations were collected from surrounding crops in each site, most of them from cereals fields. Sowing was performed in 25 cm diameter pots in October 2016 by disturbing the upper 5 cm of the soil. 100 seeds were sown per pot, with five replications. The pots were buried in the soil. Samplings were/will be done every 2-3 days or weekly by destructive counts, from October-March to March-September 2016-2017, depending on the site. Three plants per pot were assessed for phenological development according to BBCH-scale once or twice a week in the same period. Some key result on emergence percentages and rates will be presented, as well as phenological development focusing on certain growth stages (e.g. BBCH 14 -4 leaves on main shoot, BBCH 65- full flowering). Some experiences were that at southern latitudes Avena spp. emerged more in autumn or winter, while at the northern latitudes Avena spp.
