A C-banded karyotype of mitotic chromosomes in diploid purple coneflower (Echinacea purpurea L.).

BACKGROUND: Aneuploid ermpglasm is an important resource for genetic studies and identification of individual chromosomes in the cells of the aneuploid is an important step. The karyotype has already been established for purple coneflower (Echinacea purpurea L.), but due to the high similarity in the morphology of several pairs of chromosomes in this species, it cannot be used to identify individual chromosomes in its own complement. The objectives of this study are to develop and evaluate the Giemsa C-banding technique for the purpose of identifying the individual chromosomes in Echinacea purpurea.

RESULTS: The established karyotype with C-bands showed that all the 11 pairs of chromosomes possessed centromeric bands. Telomeric bands appeared most frequently in almost all the chromosomes with only two exceptions, the short arm of the chromosome 9 and the long arm of the chromosome 10. Intercalary bands were found mainly in the long arm of some chromosomes with only two exceptions, the chromosomes 1 and 2 that had intercalary bands on both arms. The chromosome 4 was the only chromosome where intercalary bands were absent.

CONCLUSIONS: Chromosomes in E. purpurea could be stained with Giemsa to bear C-bands. By classifying the chromosomes into groups and judging the C-bands, each chromosome could be identified. The methods established in this study might be used for the identification of chromosome constitution in aneuploid E. purpurea created in a breeding program.