Nuclear DNA content variation and species relationships in the genus Lupinus (Fabaceae)

The 2C nuclear DNA content has been estimated by flow cytometry in 18 species and botanical forms of the genus Lupinus (family Fabaceae), using propidium iodide as a fluorescent dye. They represented distinct infrageneric taxonomic groups and differed in somatic chromosome numbers. Estimated 2C DNA values ranged from 0.97 pg in L. princei to 2.44 pg in L. luteus, which gives a more than 2.5-fold variation. Statistical analysis of the data obtained resulted in a grouping that supports the generally accepted taxonomic classification of the Old World lupins. The rough-seeded L. princei turned out to be an interesting exception, getting closer to smooth-seeded species. Results of DNA content analyses are discussed with regards to the phylogenetic relationships among the Old World lupins and some aspects of the evolution of the genus.