- a first genetic control element (A/a) present in a dicotyledonous plant, in the form of a dominant allele (A), and of a recessive allele (a), and - a second genetic control element (G/g) present in a dicotyledonous plant, in the form of a dominant allele (G), and of a recessive allele (g), it being understood that at least the second genetic control element was introduced artificially into said dicotyledonous plant. The above combination makes it possible to control and/or modify the sex of the flowers of dicotyledonous plants.