Chromosome and Karyotype on Hybrid <i>Dendrobium bigibbum</i> and <i>D. linelae</i>

Abstract Dendrobium is the genus with the highest species diversity in Indonesia. The aesthetic value and unique structure of flower shape and color make the demand for this genus the highest compared to other genus in the Orchidaceae family. Cytological information plays an important role in the success of plant breeding programs. This research aims to study the cytology of chromosomes and karyotype in D. bigibbum and D. lineale , as well as the hybrid. Cytological observations were observed through chromosome preparations made using the squashing method. The karyotype of the hybrid chromosomes of D. bigibbum as parent male x D. lineale as parent female and D. bigibbum as parent female x D. lineale as parent male is 2n=2x=38=19m. The chromosome size of D. bigibbum was 1.84±0.30 μm, and D. lineale was 1.77±0.31 μm, while the hybrid of D. bigibbum x D. lineale had a shorter size (1.18±0.21 μm) than the hybrid of D. lineale x D. bigibbum (1.37±0.21 μm). Analysis of the A1 (≤ 0.15) and A2 (≤ 0.18) asymmetry index of these Dendrobium had small or near zero values, so heard had symmetrical karyotype pattern in the form of metacentric and low size dispersion.