Phenotypic Evaluation of Resistance to Globodera pallida Pathotype Pa2/3 in Russet-Skinned Potato

Abstract Globodera pallida , a quarantine potato cyst nematode (PCN), has had a significant economic impact on the Idaho potato industry. Developing resistant commercial varieties has been challenging because the predominant russet potato market class lacks resistance to G. pallida , and no single major resistance gene has been identified. This study characterized the phenotypic resistance to the Idaho G. pallida pathotype Pa2/3 population in a tetraploid russet potato population derived from PCN-resistant ‘Eden’ and PCN-susceptible ‘Western Russet’. A total of 227 offspring were distributed over three years with a different subset of the population evaluated each year alongside four cultivar controls, and four PCN differential clones. Phenotypic evaluations were conducted under greenhouse conditions to evaluate traits related to cyst and egg development. Progeny showing resistance similar to ‘Eden’ constituted 13.7%, 23.4%, and 18.1% based on cysts, eggs/cyst and eggs/clone, respectively. Identifying resistant progeny through this phenotypic evaluation highlights individuals likely carrying favorable alleles, providing a valuable genetic contribution for breeding programs and research.