A genetic map of an interspecific diploid pseudo testcross population of coffee

Coffee is globally one of the most important export crops and is a prominent part of the economy in more than 50 countries in Latin America, Africa and Asia. In Colombia, it has been the leading export commodity for more than a century. However, genetic research on coffee has been rather sparse and mainly focused on the two major cultivated species, Coffea arabica L. and C. canephora P., leaving unexplored the genetic potential in other species. In this study, an interspecific mapping population consisting of 101 F 1 hybrid plants from a cross between the diploid species C. liberica and C. eugenioides was evaluated for genetic segregation at 618 molecular marker loci. Of these, 168 SSRs and two ESTs exhibited polymorphic patterns that allowed segregation analysis and genetic linkage estimations. A genetic map consisting of 146 co-dominant loci and 11 predicted linkage groups was constructed using the mapping software JoinMap 3.0. The conjoined maternal/paternal map length is 798.68 cM, has an average saturation density of 6.01 cM/interval, and covers an estimated 66–86 % of the diploid coffee genome. Approximately 24 % of loci had null alleles, and 23.5 % exhibited segregation distortion. Knowledge derived from this study has important applications for quantitative trait locus analysis and marker-assisted selection in Colombian coffee breeding programs.