Genes VvPI from Vitis vinifera cv. Cabernet Sauvignon and LePI from Lycopersicon esculentum are described; together with the use of these genes to produce sterile male flowers and seedless or parthenocarpic fruits. Silencing vectors that comprise these sequences or a part thereof are disclosed. The methods of the invention are directed to producing sterile male flowers and parthenocarpic fruits by genetic silencing, and includes: obtaining the codifying sequence of Pistillata (PI)-homologous genes from the target species; analyzing the expression of the sequence obtained in step (a) to test its expression according to the pattern described for Pistillata genes; analyzing the complementation of PI-gene mutant with the PI sequence obtained from the target species, to assess that the obtained sequence fulfills the function of a PI gene; making a genetic silencing construct that comprises a region of the codifying sequence of PI in a plant expression vector; incorporation of the constructed vector into Agrobacterium tumefaciens; transforming target plants with Agrobacterium tumefaciens modified with the silencing vector and selecting said transformed plants; and checking the absence of Agrobacterium contamination and corroborating transgenic plants by transgene amplification.