Cyto-genetic diversity with special reference to medicinal plants of the Kashmir Himalaya – a review

Abstract

The present paper reviews research conducted on the cytogenetics of the plants of the Kashmir Himalaya. The review discloses that out of the total c.550 cytologically determined plants, there are c.190 genera and c.55 families of angiosperms. Among the cytologically determined species, c.50 species have been reported for the first time at global level along with varied chromosomal reports for c.110 species from the Kashmir Himalaya. The genus Jaeschkea has also been cytologically determined for the first time worldwide from the Kashmir Himalaya. The chromosome numbers in these species vary from 2n = 10 to 2n = 120 with frequency of 2n = 18 (13.73%), 2n = 16 (13.46%), 2n = 14 (7.96%) and 2n = 32 (7.41%). The reported base numbers of x = 7, x = 8, x = 9 are common ones. Most of the genera are polybasic, followed by monobasic and dibasics while tribasic taxa are least represented in the Kashmir Himalaya. New base numbers have been reported for Astragalus (x = 6), Cheiranthus (x = 6), Gypsophila (x = 13), Meconopsis (x = 7) and Saussurea (x = 18) from this region. In all, nearly 65% species are diploids and the rest (35%) are polyploids existing at various polyploid levels, with a preponderance of tetraploids. These plants depict significant level of intraspecific variability not only in chromosome numbers but also for meiotic behaviour and morphology. The knowledge of intraspecific variability of these species point out the existence of genetic diversities. Additionally, it has been observed that molecular marker studies are restricted to few plant species in the geographically diverse the Kashmir Himalaya.