Analysis of genetic linkage in the cucumber

Genetic analysis of 15 loci conditioning morphological and disease resistance characteristics indicated several linkages in the cucumber (Cucumis sativus L.) Thirteen of the 15 loci studied (all except B and R, which were linked with no recombination) were in three linkage groups. Close linkages (1 to 6 centiMorgans) were detected between u, Tu, and D. Spine size and spine frequency were not completely linked as earlier reports indicated. The ss locus for small spine size was linked to the ns locus for numerous spines and to u, Tu, D, pm, and te with probable order ns-ss-Tu-D-u-pm-te. The F locus was linked to df and df with the probable order bi-F-df. Genes cla, dm, and cp were linked with the probable order cla-dm-cp. Triple backcrosses, which included both tightly and loosely linked loci, were evaluated, and chiasma interference was usually low or even negative. There was a weak trend for greater recombination to be realized in the production of male gametes than in the production of female gametes.