Farmers grappling with the economic toll of common scab disease may soon have a powerful ally in diploid potato varieties.
Research led by Dr. Bourlaye Fofana at Agriculture and Agri-Food Canada (AAFC) has identified genetic markers crucial for developing resistance against this widespread threat to the potato industry.
Diploid potatoes have emerged as the new front-runners in breeding, offering unique advantages over traditional tetraploid varieties like Russet Burbank. With only two copies of each chromosome, diploid genetics prove easier to manipulate, allowing breeders to tap into the untapped reservoirs of genetic potential.
“Genetically, there is less of a challenge working with diploid potatoes compared to traditional tetraploid potatoes,” Fofana says, which accelerates the breeding process for desirable traits.
Common scab, characterized by unsightly lesions, can result in substantial losses when afflicted potatoes can’t be sold in fresh markets.
“There is more natural genetic diversity in wild diploid potatoes compared to tetraploids that make them interesting for breeding,” Fofana says.
This genetic diversity is harnessed to create new varieties that essentially meet the industry’s pressing demands.
At the AAFC Charlottetown Research and Development Centre, Fofana has dedicated years to studying both the genetics of common scab and its resistance in tetraploid varieties. His findings have laid the groundwork for his current work with diploid potatoes. By planting a rich collection of diploid germplasm at the AAFC Harrington Research Farm, he is looking to identify traits crucial for common scab resistance through meticulous evaluations based on surface area affected, severity, and incidence of the disease.
Working alongside fellow AAFC researchers and former students, Fofana’s team evaluated 384 diploid potato clones, marking a significant leap forward in the pursuit of disease-resistant varieties. Of those, 61 diploid potato clones were identified as resistant to common scab.
“Now we want to see how the common scab resistance of the diploid varieties translates from the research field plots to commercial field plots,” he says.
The potential benefits of these diploid potatoes extend beyond just resistance; they may also excel in yield and quality.
“The 61 clones that are resistant to common scab vary in terms of agronomic traits from each other…some combine both drought and common scab resistance while having good yield and quality,” Fofana says. “The next steps consist of continuing to evaluate the collection for more traits while advancing some selections closer to market.”
