Karyo-Morphological analyses of Drimia gigantea and Drimia Viridula; Two of the three species in Altissima complex of the family hyacinthaceae

Drimia is a heterogeneous, poorly understood genus that requires major rearrangement. Chromosome behavior of Drimia gigantea and Drimia viridula; two species in D. altissima complex was studied for karyotypes transmission of extra chromosomes pair and pollen viability. Meristematic cells at the root tips of D. gigantea and D. viridula were studied by conventional cytogenetic and karyotype analysis. Chromosome numbers were 2n = 22 and 2n = 20 for D. gigantea and D. viridula, respectively. Extra chromosome pair in D. gigantea resulted in 2n = 22. Chromosome length was 55.45 mm for D. viridula and 55.50 mm for D. gigantea. Bridge formation, laggards, chromosome exclusion and formation of 9 (3.26%), 10 (90.93%) and 11(5.81%) chromosome bodies were observed in D. gigantea, D. viridula consistently formed 10 bivalents. Pollen viability was 90.63% in D. gigantea and 94.95% in D. viridula. Karyotypic evidence suggests that an extra chromosome pair in D. gigantea evolved from fragmentation of the second-largest chromosome, the extra chromosome is not a B-chromosome because it participated in cell division. High pollen viability and frequent occurrence of ten bivalents, indicated that D. viridula is closer to the progenitors of a common genetic system within D. altissima complex. Furthermore, the karyo-morphological differences support the separation of the two taxa as distinct species.