Male and female genetic linkage map of hops, Humulus lupulus

A male and female linkage map of hop has been constructed using 224 DNA polymorphisms (217 amplified fragment length polymorphisms (AFLPs), three random amplified polymorphic DNAs (RAPDs), one RAPD-sequence-tagged-site (STS), and three microsatellite (STSs) segregating in an F-1 population of the English cullivar 'Wye Target' x the German male breeding Line '85/54/15'. Linkage between these loci was estimated using JOINMAP Version 2.0. The final map for the female parent consisted of 110 loci assigned to eight linkage groups covering a distance of 346.7 cM. For the male map, 57 loci could be mapped on nine linkage groups spanning over 227.4 cM. One of these male linkage groups (Gr09-M) presumably represents the Y chromosome, since all markers assigned (10 AFLPs, three RAPDs and one STS) were closely linked to the male sex (M). Because of their sex-specific segregation, 10 doubly heterozygous AFLPs spanning a distance of 18.7 cM could be identified as markers describing the X chromosome, which is part of the male and female map. Three STMSs, which had already proved useful in hop genotyping, could be integrated as codominant locus-specific markers and thus allowed to produce reliable allelic bridges between the female and male counterparts.