Three orchid species, namely
Dendrobium moschatum Sw.,
D. aphyllum Roxb. and
D. aggregatum Roxb, were investigated by classical cytogenetics and CMA fluorescent banding methods.
Dendrobium moschatum was found to possess 2
n=40 chromosomes whereas, 2
n=38 chromosomes found in
D. aphyllum and
D. aggregatum. The centromeric formula was 34 m+6 sm in
D. moschatum, 38 m in
D. aphyllum and 32 m+6 sm in
D. aggregatum. No gradual decrease of chromosomal length was observed in these species indicated as primitive type. The total length of 2
n chromosome complements in
D. moschatum was 55.74 μm and 59.94 μm in
D. aphyllum. Total length was remarkably less in
D. aggregatum (44.15 μm). A pair of bright CMA bands was found in the interphase nuclei of these 3 species. In metaphase stage, 6 CMA bands were found in
D. moschatum. The number of CMA bands was 4 and 10 in
D. aphyllum and
D. aggregatum, respectively. The percentage of CMA banded region in
D. aphyllum was 4.76% while it was about double in
D. moschatum (11.33%) and 3 times in
D. aggregatum (15.38%). The CMA karyotypic features suggested that number, distribution and location of CMA bands were found to be species-specific.
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