The aim of presented studies was to determine the response of 35 Avena sterilis L. accessions to the exogenous gibberellic acid supply. A. sterilis genotypes come from genebanks in Beltsville (USA), Saskatoon (Canada), Gatersleben (Germany) and Radzikow (Poland). Based on conducted analysis it could be found that Avena sterilis genotypes are very diversified in regard to the GA₃ reaction. The majority of analysed genotypes was susceptible to GA₃. AVE 2116, AVE 2122, AVE 2561, CN 25717 and PI 378832 were insensitive on GA₃. The shortest plant height among the insensitive genotypes were CN 25717 and PI 378832 accessions.
In present paper an analysis of genetic similarity of 14 A. sterilis accessions from Israel, Syria and Lebanon was conducted. Polymorphism of RAPD markers was studied. Selected primers produce 122 fragments out of which 93 were polymorphic and 19 were genotype-specific. RAPD-based genetic similarity was estimated between 0.441 (CN 20304 vs. CN 20322) and 0.775 (AVE 941 vs. PI 287211). The mean genetic similarity was calculated at 0.614. Genetic similarity matrix was applied for claster analysis through UPGMA method. Interspecific genetic diversity of Avena sterilis was higher than that evaluated on a base of molecular markers in previous studies with Avena sativa. The highest genetic similarity was estimated for accessions originating from Israel. The highest distance was noticed for accessions from Syria. Forms originating from Lebanon had a higher ressemblance to objects from Israel than those from Syria.