Abstract
The genus Drimia (syn. Urginea), commonly called squill, represents a species complex, infrageneric delimitation being ill-defined due to morphological variability, population variation within species and polyploidy. In the present study, fluorescent chromosome banding and measurements of nuclear DNA content by flow cytometry were performed in five Indian species of Drimia: Drimia indica, Drimia polyantha, Drimia razii, Drimia wightii and Drimia coromandeliana to elucidate taxonomic relationship and obtain possible insights into the evolutionary processes within this group. All taxa analyzed exhibited similar karyomorphology with subtle differences accounted by nucleolar chromosomes. Nuclear DNA content ranged from 20.41pg/2C in D. polyantha to 40.80pg/2C in D. coromandeliana and was positively correlated with chromosome number (r = 0.67, P = 0.02) and total diploid chromatin length (r = 0.59, P = 0.06). Fluorescent chromosome banding revealed the presence of CMA(+ve)/DAPI(-ve) signals associated with nucleolar chromosomes presumably coincident with NOR in all species and unique CMA(+ve) signals in diploid populations of D. indica. Satellite polymorphism between homologous NOR-bearing chromosomes was observed which supports hybrid origin of the taxon. UPGMA dendrogram and scatter diagrams based on karyological parameters indicated a close relationship of D. indica, D. razii and D. polyantha while D. wightii and D. coromandeliana appeared distant. D. wightii appeared more close to D. indica than to all other species based on genome size and karyomorphology. As a whole, D. indica showed high intra-specific variability with populations exhibiting intergrading characters with other species. In conclusion, it is likely that hybridization followed by reproductive isolation of polymorphic forms arising by adaptation to different ecological niches resulted in species diversification of Drimia in India, probably from a common ancestor similar to D. indica.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
