Cytogenetic Studies of Genus Clematis L. (Ranunculaceae) from the Western Himalayas, India

At present, population-based meiotic studies were carried out on six species of genus Clematis for documenting the genetic diversity from selected localities of Himachal Pradesh in the Western Himalayas (India). All the populations are found to be diploid with meiotic chromosome number as 2n=16. Impaired male meiosis was noted in all populations of C. buchananiana, C. connata, C. gouriana, C. grata, C. montana, and C. orientalis. However, male meiosis shows variation in meiotic behaviour in the different populations. The presence of B chromosomes in C. orientalis is reported for the first time, previously, the species is also known to have 2n=16 but without B chromosomes. These anomalous species were marked with meiotic abnormalities in the form of cytomixis, chromosomal stickiness, unoriented bivalents, formation of laggards and bridges resulting in abnormal microsporogenesis, and production of heterogeneous-sized fertile pollen grains along with reduced pollen fertility.