Researchers from the University of Wisconsin Madison are working on a project to reinvent the cultivated potato – an effort informally known as Potato 2.0.

“Potato is the world’s leading vegetable crop, but it hasn’t realized the genetic gains needed to keep pace with the industry and consumer demands,” says Jeff Endelman, UW–Madison associate professor in the horticulture department, who heads the university’s potato breeding program.

One of the main hurdles when breeding potatoes is its tetraploid genome, researchers say. Tetraploids inherit two sets of chromosomes from each parent instead of just one set, like humans and most animals. “For plant breeders, it makes it difficult to understand the genetics of traits and get rid of unfavorable genes through selection,” says Endelman.

To circumvent the challenges of tetraploidy, potato breeders around the world are working to reinvent cultivated potato as a diploid crop. UW–Madison is playing an important role in this effort as the lead institution for a project titled “Developing a new paradigm for potato breeding based on true seed.” The project was made possible through a USD3m award from the USDA Specialty Crop Research Initiative (SCRI) and USD3m in matching funds from PepsiCo and the eight universities and research institutions involved.

According to the researchers, the first step of the project is to produce diploid potatoes that still have the optimal genetics of their tetraploid relatives. This is done by pollinating tetraploid potato with special diploids (that already exist) that can act as “haploid inducers.” Haploid induction is a technique used in many crop species to reduce chromosome numbers and results in an embryo without the chromosomes of the pollen donor.

“Our goal is to create and sequence the genomes of 100 diploid potatoes, representing the russet, chip, and red market types that comprise most of US potato production,” explains Endelman.

The next step is to create lines that can be maintained as ‘true seeds’. “It takes about 2000 pounds of seed tubers to plant one acre of land, but the amount of true seed needed would fit in the palm of your hand,” says Endelman.

Another major focus of the project is to produce inbred, or self-pollinated, lines. This presents a big challenge in diploid potatoes, as is selecting for traits that potato growers want in those inbred lines. That process took decades in the early 20th century for corn breeders, but Endelman hopes to do it more quickly in potatoes, now that researchers have the genomic tools needed.

“This project marks a turning point for ‘Potato 2.0’ in the US, and everyone is enthusiastic about the potential to more efficiently deliver genetic improvements for disease resistance, climate resilience, nutritional value, and more.”