Inheritance and linkage relationships of isozyme and morphological loci in cucumber (Cucumis sativus L.).

Twenty-one polymorphic and 17 monomorphic cucumber (Cucumis sativus L.) isozyme loci were identified in 15 enzyme systems. Seven of the polymorphic loci (Ak-2, Ak-3, Fdp-1, Fdp-2, Mpi-1, Pep-gl, and Skdh) had not been described previously. Segregation in F2 and BC families for isozyme and morphological loci demonstrated agreement with the expected 1∶2∶1 and 1∶1 segregation ratio (P<0.01). Nine morphological markers were found to be linked to isozyme loci and were integrated to form a map containing four linkage groups spanning 584 cM with a mean linkage distance of approximately 19 cM. Linkage groups (A to D) contain the following loci in genetic order: A psl, Pep-la, B, Per, dm, Pgm, Mpi-1, Idh, Ar, Fdp-1, Ak-2, Pgd-1, Mpi-2 and gl; B lh, Mdh-2, Pep-gl, Pgd-2, Fdp-2, Ccu, Mdh-3, Ak-3, ll, de, F and Mdh-1, and Gr; C cor, Gpi, and Skdh; D Tu and ss. This study detected four new linkages between morphological markers (dm-psl, de-ll, ll-F, and de-F) and confirmed previously reported linkages, dm-Ar and Tu-ss. The isozyme/morphological map constructed in this study led to a more comprehensive understanding of the genetic relationships between several economically important traits.