Chromosome Numbers and Basic Chromosome Numbers in Monocotyledonous Genera of the Western Himalayas (India)

Abstract

Worldwide chromosome number information has been compiled from the literature for monocotyledonous genera whose members have been cytologically studied in the last three years from Kangra District (Himachal Pradesh) and Kashmir (Jammu & Kashmir) in the Western Himalayas, comprising 143 species of 86 genera in 12 families, many in the family Poaceae. Chromosome number information from the literature is supplemented with new and varied reports for 54 species/56 taxa from the present study. Overall, the chromosome numbers range from 2n=10 to 2n=120. Some species in all genera show a large number of cytotypes, clearly highlighting the role of inter- and intraspecific genetic diversity as well as polyploidy and dysploidy. The basic chromosome numbers in all 86 genera are reconsidered. Monobasic genera are more common in Poaceae, and polyba-sic genera are more common in the other 11 families. Polyploidy in the different genera ranges from 3x to 40x, and is quite high in certain genera (18x in Avena, Bothriochloa, Isachne, Helictotrichon and Panicum; 19x in Saccharum; 24x in Tradescantia; 28x in Eleocharis; 32x in Cyperus; 36x in Andropogon; 38x in Poa; 40x in Dioscorea). An updated checklist of chromosome number variability in these genera is given for India and world-wide.

Morphometric traits in the fine-leaved fescues depend on ploidy level: the case ofFestuca amethystinaL.

“…Moreover, about 70% of species are polyploids. The basic chromosome number in Festuca is x = 7, however, high chromosome number variations were observed ( Kaur et al, 2014 ). In our research, we dealt with one of the species belonging to the mentioned genus: Festuca amethystina L. (amethyst fescue).…”

Structural Heterozygosity in a Cytotype (2<i>n</i>=30) of <i>Arthraxon hispidus</i> (Thunb.) Makino from North-West Himalayas

“…Based on x=15, one of the probable basic number for Arthraxon (Kaur et al 2014), the presently analyzed taxon seems to exist at 2x level. The possibility of x=15 also seems to be apparent from the presence of chromosomal number, 2n=30 in A. lanceolatus and A. prionodes.…”

IAPT chromosome data 31

“…The tetraploid chromosome count of 2n = 40 was reported by several authors for this species (Mehra & Sharma, 1972;Kaur & al., 2011b;Gupta & al., 2014). Several chromosome numbers were reported for this species, namely 2n = 18 (Mehra & Remanandan, 1973), 2n = 36 (Ahsan & al., 1994, 2n = 36, 42 (Kaur & al., 2017) and 2n = 42 (Kaur & al., 2011a). The present meiotic count is the first report of 4x cytotype for the species.…”