Meiotic behaviour and its implication on species inter-relationship in the genus Curcuma (Linnaeus, 1753) (Zingiberaceae)

Volume: 11Start Page: 691End Page: 70

Heterochromatin distribution and comparative karyo-morphological studies in Vigna umbellata Thunberg, 1969 and V. aconitifolia Jacquin, 1969 (Fabaceae) accessions

Chromosome studies along with heterochromatin distribution pattern analysis have been carried out in two domesticated species of Vigna Savi, 1824 which grow in contrasting geo-climatic conditions of India: Vigna umbellata Thunberg, 1969, a legume well acclimatized to subtropical hilly regions of North-east India and V. aconitifolia Jacquin, 1969, a species of arid and semi-arid regions in desert plains of Western India. Karyo-morphological studies in both species reveal 2n = 22 chromosomes without any evidence of numerical variation and the overall karyotype symmetry in chromosome morphology suggest that the diversification at intraspecific level in genus Vigna has occurred through structural alteration of chromosomes, rather than numerical changes. Heterochromatin distribution as revealed by fluorochrome binding pattern using CMA3 and DAPI, confirms the occurrence of relatively more GC content in V. aconitifolia as compared to V. umbellata. However, AT content was found to be comparatively higher in V. umbellata which perhaps play a role in species interrelationships

Genetic diversity and population structure assessment using molecular markers and SPAR approach in Illicium griffithii, a medicinally important endangered species of Northeast India

Abstract Background Illicium griffithii is an aromatic medicinal tree species that has been listed in the IUCN Red List as an endangered species. Dried seed pods of I. griffithii have a good market potential in the spices and pharmaceutical industries. Fruits are the potential source of shikimic acid and used for the production of oseltamivir (a drug against bird flu). However, in recent years, unscientific harvesting and rampant exploitation of the species has caused a negative and adverse effect on its natural population. Proper knowledge of genetic diversity and population structure is crucial to understand the population dynamics, adaptation, and evolutionary pattern of a particular species for conservation. It was from this view point that the present study was undertaken so as to compare the various types of DNA-based molecular markers namely RAPD, ISSR, DAMD, and SCoT by their efficiency and SPAR approach to evaluate the genetic diversity of I. griffithii as well as to analyze population genetic structure for conservation purpose. Result A total of 250 discernible bands were generated with 246 bands (98.40 %) being polymorphic in nature. All the primers in combination gave a mean polymorphic information content (PIC) of 0.81 and Rp value (resolving power) of 4.32. Nei’s, Gst, and AMOVA analysis showed similar values of genetic differentiation among populations (Gst = 0.396, FST = 0.30, respectively), revealing a low level of genetic differentiation among the eight sampled populations. I. griffithii with an estimated gene flow value of Nm = 0.761 was significantly low among populations. Clustering pattern obtained with Bayesian structure and PCoA diagram revealed that intermixing of genetic material across populations is only possible when the populations lie close to each other. This is further validated with UPGMA clustering method where a positive correlation of genetic variability with geographical distance among closely related populations could be clearly seen. Conclusion The result aids in the identification, collection, and preservation of diverse germplasm of I. griffithii from Arunachal Pradesh and Meghalaya of Northeast India. This would further help in understanding the population structure and genetic diversity among other Illicium species in order to formulate effective conservation strategies for the improvement of this endangered taxa

Induction and evaluation of colchitetraploids of two species of Tinospora Miers, 1851

Volume: 14Start Page: 211-22

Allium cytogenetics: a critical review on the Indian taxa

The genus Allium Linnaeus, 1753 (tribe Allieae) contains about 800 species worldwide of which almost 38 species are reported in India, including the globally important crops (onion, garlic, leek, shallot) and many wild species. A satisfactory chromosomal catalogue of Allium species is missing which has been considered in the review for the species occurring in India. The most prominent base number is x=8, with few records of x=7, 10, 11. The genome size has sufficient clues for divergence, ranging from 7.8 pg/1C to 30.0 pg/1C in diploid and 15.16 pg/1C to 41.78 pg/1C in polyploid species. Although the karyotypes are seemingly dominated by metacentrics, substantial variation in nucleolus organizing regions (NORs) is noteworthy. The chromosomal rearrangement between A. cepa Linnaeus, 1753 and its allied species has paved way to appreciate genomic evolution within Allium. The presence of a unique telomere sequence and its conservation in Allium sets this genus apart from all other Amaryllids and supports monophyletic origin. Any cytogenetic investigation regarding NOR variability, telomere sequence and genome size in the Indian species becomes the most promising field to decipher chromosome evolution against the background of species diversity and evolution, especially in the Indian subcontinent