INTERSPECIFIC RELATIONSHIPS IN FAGOPYRUM (POLYGONACEAE) REVEALED BY THE NUCLEOTIDE-SEQUENCES OF THE RBCL AND ACCD GENES AND THEIR INTERGENIC REGION

DNA sequences of the rbcL and accD 5' coding regions and their interge nic region (IGR) were determined in 20 taxa of 12 species of Fagopyrum . By comparing the sequence data and constructing phylogenetic trees, phylogenetic relationships among Fagopyrum species were investigated. The acc-D 5' coding region and the IGR have evolved about five times f aster than the rbcL coding region; hence the phylogenetic trees based on the data of the accD 5' coding region, the IGR, and these data comb ined, had higher resolution than the bees based on rbcL alone. The cla ssification of Fagopyrum based on the DNA sequences was almost perfect ly consistent with the classification by Ohnishi and Matsuoka (1996, G enes & Genetic Systems 71: 383-390). New facts and minor differences a re (1) polyploidization in F. cymosum might have occurred more than on ce, (2) F. lineare may not be a sister species of F. leptopodum, and ( 3) F. pleioramosum rather than F. capillatum may be a sister species o f F. gracilipes.