Genetic diversity and taxonomic relationships of some Ipomoea species based on analysis of RAPD-PCR and SDS-PAGE of seed proteins

To elucidate the genetic diversity of ten Ipomoea species, seed proteins were analyzed by SDS-PAGE and RAPD analysis. According to SDS-PAGE analysis, in total 51 different bands were identified across the studied species. The number of bands varies from 16 bands in Ipomoea cairica, to 3 bands in I. sinensis. The similarity analysis based on the SDS-PAGE profile turned out to be a useful character for the inequity of Ipomoea species both on the subgeneric and sectional level. Analysis of RAPD-PCR of DNA provided more precise information concerning relationships between Ipomoea sections than SDS-PAGE analysis. A remarkable result from this study was identifying a close relationship between Ipomoea purpurea of section Pharbitis (subgenus Ipomoea) and species of the subgenus Quamoclit. Further support comes from the molecular data of RAPD which indicate that Ipomoea cairica should be considered a well separated section which may be related to section Orthipomoea. Our results suggest that section Erpipomoea is not a monophyletic group, whereas species of section Orthipomoea form a single monophyletic section.