Its the pistil (ovary) that after fertilization form embryo inside and develops into fruit.
The flower is the reproductive part of the plant and this is very essential for the plants to propagate their species. The flower contains, both male and female parts and the female part is called the pistil. Within the pistil, there are there parts, the stigma, style and ovary. The male part of the flower is called stamen and contains the anther and filament. The pollen from the anther lands on the stigma which is the opening to the system. It moves through the style into the ovary. The ovules are fertilized in the ovary and then the ovary forms into fruit while all the other parts wilt and fall off.