The historic rivalry between Chile and Peru has in the past seen them arguing over territory and the rights to Pisco, an alcoholic drink.
A US study found that all varieties can be traced back to Peru
But few imagined that the neighbours would one day be fighting over the humble potato.
It all started when a Chilean expert announced plans to register over 280 potato varieties from the southern island of Chiloe as national patrimony.
Angry Peruvians hit back, saying their nation is the birthplace of the potato.
The controversial idea comes from Professor Andres Contreras, from the Agricultural Sciences Faculty at Chile's Austral University.
He says he only wants to register what belongs to Chileans.
"These potato varieties have grown and developed in this country, and we would like to protect them," he says.
"We don't want unscrupulous people claiming rights to them and asking for money.
"We are not saying that potato is from Chile. We are only trying to shield local varieties," he insists.
Peru has described the Chilean plans as "inappropriate".
"It has been widely accepted that potato originated in southern Peru and therefore belongs to our nation's cultural heritage," said Foreign Minister Oscar Maurtua.
He added that a recent study sponsored by the US Department of Agriculture supported the Peruvian claim.
The research found that all modern varieties of potatoes can be traced back to a single source - a spud grown in Peru over 7,000 years ago.
Last year, Peru's Congress passed a bill aimed at protecting the potato and the Andean country now plans to patent it internationally as a Peruvian product.
Peru is threatening to take the case to the United Nations.
The two countries have a history of disputes dating back to the 19th Century, when Chile fought the War of the Pacific against Peru and Bolivia from 1879 to 1883, winning Bolivia's outlet to the sea and extensive areas from Peru.