XVI International Botanical Congess

Functional relationships among floral parts may lead to evolutionary changes in correlations among these parts. Anther exsertion is determined by the relative lengths of the filaments and corolla tube. Comparative analysis in the Brassicaceae suggests that a high correlation between these traits has evolved from an lower correlation in several species, including wild radish. However, field studies on wild radish provide only weak evidence for selection on anther position. Results of a random mating study suggest that all floral correlations in wild radish are due to pleiotropy. Artificial selection to recreate the lower correlation between filament and corolla tube in wild radish produced a rapid response, in spite of the fact that the strong pleiotropic correlation between these traits should cause an evolutionary constraint.