Researchers at the hybrid potato breeding company Solynta and Wageningen University & Research have identified, cloned and characterized the gene for self-compatibility in potatoes called Sli (S-locus inhibitor). This discovery will have a profound impact on potato breeding. With Sli defined, breeders can implement hybrid breeding, which will allow for faster and focused rather than opportunistic breeding. This focused breeding can quickly bring new resilient and nutritious varieties to the market that will help make potato production become more sustainable. The result of the team’s molecular analysis of Sli has been published in the scientific journal Nature Communications.

Despite its familiarity, the cultivated potato has a surprisingly complex genome, making it very difficult to improve using traditional breeding techniques, with time spans of 10-15 years between the first cross and the final commercial cultivar. For this reason, over the last 100 years, improvements in key traits such as disease resistance, adaptation to climate change and yield, have been modest.

Hybrid breeding – a non-GMO technique – is based on the cross-breeding of diploid potatoes, in which every cell contains two complete sets of chromosomes (one from each parent) rather than our cultivated potato, which has a complex genome consisting of four sets of chromosomes. In order to actually capitalize on the opportunities of hybrid potato breeding it was crucial to identify, clone and characterize the key gene for self-compatibility in potato called Sli (S-locus inhibotor), says Professor Richard Visser of the Plant Breeding group of Wageningen University & Research (WUR). “An important element of hybrid breeding is the fixation of traits of the two parental lines through inbreeding. In the course of evolution many plants including almost all diploid potatoes have prevented inbreeding by becoming self-incompatible, but we are now able to overcome this through the Sli gene in potato. Self-compatibility as such and also the location on chromosome 12 were already known for some time, but so far the gene encoding of this trait was unknown and had not been isolated and characterized. Through genetic analysis and genome sequencing we’ve succeeded in doing this. This now gives us the key to fast and effective breeding of new diploid potatoes.”

Ernst-Jan Eggers, genetics researcher for Solynta explains the company is “already using the Sli gene by crossing self-incompatible diploid lines with a Sli gene donor. With these new insights, we may be able to discover new variants of Sli that could improve our ability to select for improved taste, water use efficiency, disease resistances and other characteristics for our ever-changing world.