They are the fruits that form from the flowers, containing seeds from which potatoes can be grown.

And remember that they are very poisonous so do not be tempted to eat them.
The seeds in these fruits can be grown on to produce tubers, but what you would get would not be the same as the plant from which they came.
Seed potatoes are merely small versions of big ones, not grown from seed, except when they are producing new varieties.

Potatoes and tomatoes are of the same family but have very different characteristics. With tomatoes you can safely eat these fruits but on potatoes they are poisonous.

thanks to all for the information. after 50 years of messing in garden i had never come across seed pods on potatoes. once again thank you.