A genetic system for controlling the type of floral development of a dicotyledon plant, includes the combination of two genetic control elements, respectively: a first genetic control element (A/a) present in a dicotyledon plant, in the form of a dominant allele (A), and a recessive allele (a), and a second genetic control element (G/g) present in a dicotyledon plant, in the form of a dominant allele (G), and a recessive allele (g), provided that the first genetic control element has been artificially inserted into the dicotyledon plant. This system enables the sex of the flowers of dicotyledon plants to be controlled and/or modified.