Abstract: A new kind of petunia ( Petunia hybrida L. ) floral mutant, designated as e fficient (eff), was characterized as having increased ntanber of organs in all floral whorls compared with the wild type. The number of carpel was steadily increased up to 3 to 4. The pistil had a 3- or 4-lobbed stigma. Meanwhile, petaloid structures developed on top of the stamens, but pollen formation and anther dehiscence were not affected. After fertilization, the mutant flower formed a larger fruit consisted of more than two loculi. Scanning electron microscopic observations revealed that the increased organ number and petaloid structure occurred at primodia stage in the mutant. This eft mutation acted as a single Mendelian trait in genetic crosses. The phenotype of the mutant flower are advantageous to sexual reproduction process of plant.

Key words: Flower, Mutant, Petunia