Genetic diversity in Chaenomeles (Rosaceae) revealed by RAPD analysis

Genetic relatedness in Chaenomeles was studied by RAPD analysis in 42 plants representing accessions of three wild species and one hybrid taxon. Amplification with 17 primers yielded a total of 156 polymorphic RAPD bands. Estimates of genetic relatedness suggest that C. cathayensis and C. japonica are the most distantly related species, and that the former is comparatively homogeneous. Chaenomeles speciosa, which may have arisen through hybridization between C, cathayensis and C. japonica, takes an intermediate position between these two species. Analysis of diagnostic bands demonstrate that neither C. speciosa nor C. x superba has any bands that do not occur in at least one of C. cathayensis or C. japonica. Moreover, C, speciosa and the partly overlapping taxon C. x superba are comparatively heterogeneous, which is also in accordance with a hybrid origin. Intraspecific variation was studied mainly in C. japonica; plants obtained from different sources of material formed well separated groups in the cluster analysis.