The hot summer followed by a rainy spell in August was given as the reason for the misshapen vegetables produced at Mr Dunne's farm near Ludlow.
He made the comments at a Public Bill Committee meeting on the Agriculture Bill.
In response to a proposed amendment by Labour MP Kerry McCarthy on setting mandatory food waste reduction targets, Mr Dunne used his potato plight as an example of how farmers can find themselves with a surplus of produce which has been rejected by buyers on cosmetic grounds.
He said: “We have a potato crop, and the very dry conditions through the summer, followed by some rain in August, have led to a large proportion of the potatoes in unirrigated fields developing what are called ‘dolly heads’, where there is an extra spurt of growth, and the potato, instead of being a single shape, has a misshapen bit alongside.
“To get buyers to accept loads that contain those shapes, we have to send samples off to them. They decide whether to accept or reject them; sometimes, we send the entire load off and it is rejected on sight and sent back to the farm.
“We cannot anticipate precisely how the supermarket or intermediary will react until they see the load.”
Mr Dunne said the proposed amendment would lead to “extreme complications” for farmers when deciding what to do with the rejected produce.
But he did not have to worry – the amendment was deemed unnecessary by George Eustice MP, minister for environment, food and rural affairs.