Microevolution and invasiveness of Oenothera L. species (subsect. Oenothera, Onagraceae) in Europe

Abstract

A comparative analysis of Oenothera’s hybrid species was carried out. The genus Oenothera L. (subsect. Oenothera , Onagraceae) is one of the most widespread American genera in Europe. These species possess a special breeding system (permanent translocation heterozygosity) which promotes the hybridization (also introgressive one) among any species resulting in formation of a hybrid with a constant complex of morphological characteristics. The analysis of hybrid species distribution in Europe using published and original data proved the existence of groups with different degrees of invasiveness. A positive correlation between the degree of invasiveness of the parental species and the invasiveness of hybrid ones was shown. As a rule, the aggressive hybrids originated from aggressive parents. The most aggressive hybrids were formed after a crossing of North American with European species; perhaps such hybridization leads to the heterosis effect among normally isolated genes. The invasiveness of morphologically similar hybrids correlates both with their genetic features and with the abundance of the parental species. The new evolution branch of ring-forming species of Evening primroses is distinguished by high invasiveness in comparison with bivalent species. The invasiveness of the model species depends on plant cytotypes.