Potato researchers uncover a 10,000 year old secret

Munich Researchers Look into the Genetic Core of Historical Potato Varieties - and Are Surprised

The potato feeds more than 1.3 billion people worldwide - despite the groundbreaking successes of breeding, the achievements are by no means revolutionary. Many of the most widely used potatoes were bred many years ago. A press release from Ludwig Maximilian University (LMU) in Munich cites the complex genome of the potato as the reason for the rare breeding success: In each cell, there are four genomes instead of just two. Munich researchers from LMU and the Max Planck Institute for Plant Breeding Research have apparently been able to unravel the mystery of Europe's potatoes and decode the genome of important varieties.

Historical Varieties Lead the Way to the Modern Genome

As reported by the researchers in the prestigious journal Nature, they were able to reconstruct the genome of ten historical potato varieties and used this knowledge to reconstruct other potato genomes significantly easier and faster.

The Munich team, together with researchers from Wageningen University, the Leibniz Institute for Plant Genetics and Crop Plant Research (IPK), and Xi'an Jiaotong University in China, selected historical varieties that were cultivated as early as the 18th century. During this time, European breeding programs began. The researchers wanted to first determine how much diversity was present in these potatoes in order to understand "how high the genetic potential of our potatoes is," as LMU Professor Korbinian Schneeberger, the team leader, says.

The results showed that the diversity is limited. The genetic pool of the potato is extremely limited: the ten examined potatoes already cover 85% of the genetic variability of all modern European potatoes.

Potatoes from South America Fail in Europe

The researchers explain this with bottleneck effects: Most of the potato lines imported from South America since the 16th century failed in European conditions. Diseases further reduced the gene pool. The most famous example is the potato blight, which in the 1840s in Ireland, but also in the rest of Europe, led to almost complete crop failure and catastrophic famines.

Indigenous Peoples Have Created Genetic Diversity for 10,000 Years

At the same time, the study, to the surprise of the researchers, showed that the differences between individual genome components can be enormous. "There are not many different chromosomes, but if the chromosomes are different, then to an extent that we have never seen in domesticated plants," says Schneeberger. The differences are about twenty times what is the case in humans. These differences were probably created by those indigenous peoples who domesticated potatoes in South America 10,000 years ago.

Fry Variety Dates Back to 1908

Finally, the researchers developed a novel approach to analyze the genomes of the approximately 2,000 potato varieties registered with the EU in the future. Instead of reconstructing a genome, easily generated data are compared with the now known genomes to determine which of the known chromosomes are present in a variety. The researchers demonstrated that this works, for example, with the potato variety Russet Burbank, which has existed since 1908 and is still one of the standard fry varieties.