Karyotypic Studies in Artificial Hybrids of Solanum Sections Anarrhichomenum and Basarthrum (Solanaceae)

Abstract

Mitotic chromosomes of seven artificial hybrids fromSolanum L. sect.AnarrichomenumBitter &Basarthrum (Bitter) Bitter were studied(S. caripense Humb. & Bonpl. ex Dunal ×S. basendopogon Bitter,S. caripense × S. muricatumAiton, S. muricatum ×S. basendopogon, S. muricatum× S. caripense,S. muricatum× S. cochoae G.J. Anderson & Bernardello, S. sodiroi Bitter ×S. brevifolium Humb. & Bonpl., andS. sodiroi ×S. caripense).All are wild species except S. muricatum, which is knownonly as a domesticate (‘pepino dulce’). All hybrids were diploidwith 2n = 24. We compare the karyotypes ofparental species and their hybrids to understand chromosome change as acomponent of the evolution of these sections. Statistical analyses ofchromosomes, genome length and centromere position yielded estimates ofkaryotype composition and asymmetry. Comparisons were made by means of ANOVAsand numerical taxonomic methods. Statistical comparisons among the hybridspooled showed much karyotypic similarity among them. Karyotypes of theparental species revealed sharper differences among them. The karyotypes ofthe hybrids except for one combination were not intermediate. In general, thekaryotypes of the hybrids showed relatedness to the karyotype of one parentalspecies. The hybrids involving S. muricatum havechromosomal features closer to it than to the other parental species. Previousstudies showed S. caripense among the wild species to bemost similar to S. muricatum and, as expected, therewere the fewest differences between these species and the hybrids betweenthem. The karyotype of S. sodiroi×S. brevifolium is the most different from the karyotypeof either of its parental species.