Comparative Karyo-morphology of the two endemic and critically-endangered species of mantisia (Zingiberaceae)

Karyo-morphological studies have been carried out in two critically rare, endangered and endemic rhizomatous, horticulturally important species of genus Mantisia (Zingiberaceae) from North-East India. The somatic chromosome number (2n=20) has been recorded in both M. spathulata and M. wengeri with distinct inter-specific variation in the arm ratio of homologous pairs in the complements. All the chromosomes were sub-metacentric in nature (20 L) and more or less symmetrical karyotypes in both the species indicating stabilized genomic pattern. In M. wengeri two chromosome pairs exhibited heteromorphy. Nucleolar organizing region (NOR) and meta-, telo-, and subtelocentric chromosomes were absolutely lacking. Chromosome class based on total length of each chromosome as well as its designation through centromeric position was determined. This karyo-morpological study provides valuable baseline genetic data for clearly distinguishing Mantisia (x=10) from its phenotypically very similar allied genus Globba L. (x=8). Thus, present investigation provides valuable insight on karyotypic variation, speciation and evolution of the genus Mantisia and also addresses the conservation concerns.