Format: ORAL

Manoj M. Lekhak*, Priya E. Shelke, Shrirang R. Yadav

Shivaji University, Kolhapur, India

Dipcadi Medik. (Asparagaceae) is a bulbous monocot with less than 50 species distributed in Africa, Europe, the Indian subcontinent and Madagascar. India has 13 species with a maximum concentration (11 species) in peninsular India. Cytogenetically the genus is well-known for its bimodal karyotype wherein two sets of chromosomes of contrasting sizes are found. Taxonomy of the genus has always been convoluted on account of the uniformity of morphological features and their short flowering period. Moreover, these species make poor herbarium specimens because of their succulent nature and hence are underrepresented in Herbaria across the globe. Here, we studied the cytogenetics of 23 accessions distributed across 11 species to refine their taxonomy. The variation in diploid chromosome number (2n) indicated the presence of three chromosome counts, i.e. 2n = 12, 20 and 22 chromosomes. D. concanense, D. goaense, D. janae-shrirangii, D. reidii, D. saxorum, accessions collected from Ankai fort, Delhi, Gautala and Mhaismal had 2n = 12 chromosomes whereas D. coimbatorensis, D. krishnadevarayae, D. montanum var. madrasicum, D. ursulae, D. ursulae var. longiracemosum, accessions collected from Ajara, Badami, Belgaum, Dapoli, Dolkhamb, Halkarni, Rantale and Yercaud had 2n = 20 chromosomes. D. erythraeum had 2n = 22 chromosomes. The mean chromosome length (MCL) varied from 1.52 9.31 m and the total length of the haploid complement (THL) was 24.76 48.91 m. Both bimodal and trimodal karyotypes were observed. Trimodal karyotypes were confined to species with 2n = 20 and 22 chromosomes. Male meiosis was found to be normal. Our findings suggest that cytogenetical information, viz. chromosome number and morphology cannot fully discriminate between species and hence an integrated approach involving molecular cytogenetics or molecular phylogenetics should be applied to resolve the identity of species.