The cryptic inheritance of genetic resistance of potato against common scab

Common scab (CS), caused by multiple Streptomyces species, is a major skin disease in potatoes worldwide, leading to a significant loss of marketable yield in severely affected fields. This disease causes raised, superficial or pitted lesions on potato tubers. Resistant varieties are the most effective scab management, as irrigation-based control is costly and unsustainable long-term. However, phenotypic evaluation of CS resistance is difficult and frequently unreliable due to strong environmental effects. 
My project aimed to develop genotypic and phenotypic tools to enhance selection of resistant varieties, thereby improving breeding efficiency and reducing costs compared to conventional field screening methods. I combined phenotypic, marker-based, and genomic selection methods to understand the genetic architecture of resistance. Genome-wide studies revealed that resistance is controlled by many small-effect genes, underscoring the need for genomic selection, as traditional marker-assisted methods alone may be insufficient. Furthermore, a lab-based phenotyping method showed good potential for identifying scab-resistant genotypes.