ISOZYME AND SEED PROTEIN PHYLOGENY OF THE GENUS CITRULLUS (CUCURBITACEAE)

Electrophoretic analysis of 26 enzyme coding genes was conducted on accessions of three Citrullus species and the related Praecitrullus fistulosus and Acanthosicyos naudinianus. The isozyme phylogeny of the genus Citrullus and the related species was constructed based on pairwise measurements of the respective genetic distances between the species and races. P. fistulosus and A. naudinianus form two distinct outgroups to Citrullus which is characterized by two main clusters: The first includes two C. colocynthis races and the second, C. lanatus and C. lanatus var. citroides, which are more closely related to each other than they are to C. ecirrhosus. The isozyme phylogeny is consistent with the variability in six seed protein bands and with the crossability relations among the examined species.