Population Genetics and Association Mapping

We have entered a rapidly changing period where new technology and new analysis techniques provide opportunities for crop improvement. Molecular markers have long held the promise of improving the effi ciency and effectiveness of plant breeding. Due to the autotetraploid state of potato (Solanum tuberosum L.), researchers have primarily utilized diploid genetic materials for genetic map construction and the identifi cation of markers linked to important traits (reviewed by Gebhardt 2005). These markers have proven useful for enhancing our understanding of cultivated potato and wild Solanum species used as sources of benefi cial diversity by potato breeders. Application of association genetics to tetraploid breeding populations (see Chapter 7) will further contribute to the identifi cation of valuable markers for potato improvement. Gene cloning and transformation technology offer a route to overcome the weaknesses inherent to widely grown potato cultivars; however, lack of consumer and industry acceptance of genetically modifi ed organisms has limited the impact of this technology to date. Advances in potato, and the closely related tomato (Solanum lycopersicon), genome sequencing will greatly improve our knowledge of the gene content and genome organization of potato. Next-generation sequencing, high-throughput genotyping, and bioinformatics will further contribute to the evaluation of allelic diversity existing in S. tuberosum and related species. The question that has yet to be answered is whether this wealth of genomics information will have an impact on potato breeding.