22 October 2020
Working to reinvent cultivated potato as a diploid crop
ONE of the main hurdles when breeding potatoes is its tetraploid genome. Tetraploids inherit two sets of chromosomes from each parent instead of just one set, like humans and most animals.
To circumvent the challenges of tetraploidy, potato breeders around the world are working to reinvent cultivated potato as a diploid crop, an effort informally known as Potato 2.0. The University of Wisconsin–Madison in the USA (UW–Madison) is playing an important role in this effort as the lead institution for a national project titled 'Developing a new paradigm for potato breeding based on true seed.' The project was made possible through a $3 million award from the USDA Specialty Crop Research Initiative (SCRI) and $3 million in matching funds from PepsiCo and the eight universities and research institutions involved.
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.
The 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.
The next step is to create lines that can be maintained as seed.
Another major focus of the project is to produce inbred, or self-pollinated, lines.