P1. Syst. Evol. 172, 65-75 (1990) Plant. Systematics and Evolution ©by Springer-Verlag 1990 Chloroplast DNA diversity in the genus Rubus (Rosaceae) revealed by Southern hybridization R. WAUGH, W. T. G. VAN DE VEN, M. S. PHILLIPS, and W. POWELL Received June 30, 1989 Key words: Angiosperms, Rosaceae, Rubus. - Chloroplast DNA, restriction fragment length polymorphism, cladistic analysis. Abstract: The variability in chloroplast DNA type of 20 Rubus genotypes was examined by Southern hybridization. DNA extracted from the Rubus accessions was digested with two restriction enzymes (EcoR! and EcoRV) and heterologous chloroplast DNA sequences from barley and pea were used as probes to detect Rubus chloroplast DNA sequences on Southern blots of Rubus total DNA. Restriction fragment length polymorphismwas detected and a total of 92 restriction fragments were generated by the probe/enzyme combinations examined. Cladistic principles based on the parsimony assumption were used to assemble a phylogenetic tree based on chloroplast restriction fragment length data. The phylogenetic tree grouped the taxonomically defined species and is in general agreement with information based on morphological criteria. However, the Japanese red raspberry R. illecebrosus was shown to have diverged considerably in terms of evolutionary time from other species in subg. Idaeobatus. Furthermore, the molecular approach provides a quantitative estimate of the relationship between species that is difficult to obtain from morphological data. In order to complement the chloroplast DNA information a ribosomal DNA probe was also included in the analysis and provided further information on the phylogenetic relationships within Rubus. Rubus is one of the most diverse genera in the plant kingdom (JENNINGS 1988). In addition to the domesticated cultivars of edible fruits there is a wide diversity of wild species. Three subgenera contain cultivated fruit: Idaeobatus (raspberries), Eubatus (blackberries) and Cyclactis (arctic raspberries). In addition, subg. Ano- plobatus (flowering raspberries) has been used in breeding programmes. Subgenus Idaeobatus consists of approximately 200 species of which the most important are the European and N. American red raspberries (Rubus idaeus L. subsp, vulgatus ARRHEN and R. idaeus subsp, strigosus MICHX, respectively), and the black raspberry (R. occidentalis L.). These species are primarily distinguished by the ability of the mature fruit to separate from the receptacle. Subgenus Cyclactis is taxonomically close to subg. Idaeobatus and includes the important arctic rasp- berries R. arcticus L. and R. stellatus SM., as well as the well known cloudberry, R. chamaemorus L. Subgenus Eubatus is extremely variable and complex. Within it, the ploidy range extends from diploid (2x=2n=14) to dodecaploid