title: Tagging quantitative trait loci for maturity-corrected late blight resistance in tetraploid potato with PCR-based candidate gene markers.
abstract: Late blight caused by the oomycete Phytophthora infestans is the economically most important and destructive disease in potato cultivation. Quantitative resistance to late blight available in tetraploid cultivars is correlated with late maturity in temperate climates, which is an undesirable characteristic. A total of 30 DNA-based markers known to be linked to loci for pathogen resistance in diploid potato were selected and tested as polymerase chain reaction-based markers for linkage with quantitative trait loci (QTL) for late blight resistance and plant maturity in two half-sib families of tetraploid potatoes. Most markers originated from within or were physically closely linked to candidate genes for quantitative resistance factors. The families were repeatedly evaluated in the field for quantitative resistance to late blight and maturity. Resistance was corrected for the maturity effect. Nine of eleven different map segments tagged by the markers harbored QTL affecting maturity-corrected resistance. Interactions were found between unlinked resistance QTL, providing testable strategies for marker-assisted selection in tetraploid potato. Based on the linkage observed between QTL for resistance and plant maturity and based on the genetic interactions observed between candidate genes tagging resistance QTL, we discuss models for the molecular basis of quantitative resistance and maturity.
authors.affiliation: Max-Planck-Institute for Plant Breeding Research, Carl-von-Linné Weg 10, D-50829 Cologne, Germany.
authors.forename: Christina Angelika
authors.initials: CA
authors.lastname: Bormann
authors.forename: Andreas Marcus
authors.initials: AM
authors.lastname: Rickert
authors.forename: Rosa Angela Castillo
authors.initials: RA
authors.lastname: Ruiz
authors.forename: Jürgen
authors.initials: J
authors.lastname: Paal
authors.forename: Jens
authors.initials: J
authors.lastname: Lübeck
authors.forename: Josef
authors.initials: J
authors.lastname: Strahwald
authors.forename: Karsten
authors.initials: K
authors.lastname: Buhr
authors.forename: Christiane
authors.initials: C
authors.lastname: Gebhardt
mesh_terms: D000483:Alleles; D018744:DNA, Plant / Q000235:genetics; D017343:Genes, Plant; D005819:Genetic Markers; D005838:Genotype; D008957:Models, Genetic; D010838:Phytophthora / Q000472:pathogenicity*; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D016133:Polymerase Chain Reaction; D011123:Polyploidy; D040641:Quantitative Trait Loci; D011198:Solanum tuberosum / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology*
chemical_list: D018744:DNA, Plant; D005819:Genetic Markers