Although home gardeners may think potato plants flower to signify that it is time to harvest early or "new" potatoes, the plant flowers for the same reason all plants flower: to sustain the species from season to season providing seed for the next generation. Farmers use conventional seed tubers to start new plants, but breeders use true potato seed for propagating new species more resistant to disease and better suited to particular climates.
The potato flower must attract insects to suck the pollen within it. The flower's pollen attaches to the insect's body as it eats.
The insect moves from flower to flower nourishing itself with each flower's nectar. As it does this, it spreads one flower's pollen to the other flowers.
The insects spreading of pollen from flower to flower fertilizes the plant flower.
Once a flower has been fertilized, seed formation is on its way. A potato flower turns into a potato berry as its seedpod.
As the seedpod matures, the seed inside becomes viable and capable of growing a potato plant for the next season. Breeders take advantage of this true potato seed to create new varieties of potato, something that cannot be done with conventional seed tubers.