Phylogenetic relationships among several African Cucumis species

Abstract

Cotyledons of seven African species within Cucumis, subgenus Melo, subgroup Myriocarpus (4x C. aculeatus, C. anguria var. anguria Meeuse, C. dipsaceus Ehrenb. ex Spach, C. ficifolius A. Rich, C. myriocarpus ssp. leptodermis Schweik., C. prophetarum, and 2x and 4x C. zeyheri Sond.), and 2x C. sativus L. of subgenus Cucumis were surveyed using horizontal starch gel protein electrophoresis to characterize interspecific and intraspecific variation. Cluster and classification and regression tree analysis of allelic frequencies among 14 polymorphic loci indicated that C. myriocarpus ssp. leptodermis, C. prophetarum ssp. dissectus, C. ficifolius, C. anguria var. anguria, and 2x and 4x C. zeyheri have biochemical affinities and could be distinguished from C. aculeatus and C. dipsaceus, which were similar. Within the first group, C. myriocarpus ssp. leptodermis and C. prophetarum ssp. dissectus accession formed a well-defined group. Cucumis prophetarum ssp. dissectus was more similar to C. myriocarpus ssp. leptodermis than to the C. ficifolius accessions evaluated. In the second group, two C. zeyheri accessions (C81321, C80346) were more similar to C. prophetarum ssp. prophetarum (C82069) than four other C. zeyheri evaluated. Cucumis sativus was dissimilar from all other species studied. Key words: evolution, biochemical genetics, isozymes.