Loci Involved in Domestication and Improvement of Cultivated Potato As Revealed through Genotyping of Two Diversity Panels

Potato is the world’s most important non-cereal food crop and is gaining importance in developing countries as a food source due to its high yield potential and adaptability. Cultivated potato (Solanum tuberosum) is a heterozygous autopolyploid (2n=4x=48) that was domesticated in the Andes from wild Solanum species.  To better understand the genetic relationship among Solanum species and between wild species, landraces, and cultivated potato germplasm, we constructed a diversity panel (Solanum sect. Petota Diversity Panel) of 74 plant introductions from 25 wild Solanum species and landraces that represent the diversity of tuber-bearing Solanum species and genotyped these accessions using 8303 single nucleotide polymorphism (SNP) markers.  A phylogeny generated from the SNP data largely support existing taxonomic relationships among these species and validated the use of this dataset to resolve relationships between the Solanum sect. Petota Diversity Panel and a diversity panel composed of 213 tetraploid cultivars and breeding lines from the USDA Solanaceae Coordinated Agricultural Project.  Comparison of allele frequencies between the Solanum sect. Petota Diversity Panel and the cultivated tetraploid panel revealed numerous loci with diverged allele frequencies including genes involved in carbohydrate metabolism and tuber development, consistent with phenotypic features of potato domestication and improvement. Further characterization of these two panels at a higher resolution such as that provided by whole genome resequencing will reveal additional loci involved in domestication and improvement of this important tuber crop.