Chromosome numbers and meiotic behavior in some species of Asteraceae from high altitudinal regions of Kashmir Himalayas
2021
Tantray, Younas Rasheed | Jan, Ishrat | Wani, Mohammad Saleem | Singhal, Vijay Kumar | Gupta, Raghbir Chand
Disparity or continuity in the chromosome count within taxa of various categories has been verified to be an imperative character for taxonomic classification. Male meiotic studies in 64 species (161 accessions) of composits from geographically isolated regions were examined in detail in order to update the existing knowledge of meiotic chromosome numbers of composits from the outer part of the Himalayas. Myriactis javanica (2n = 36) and Tanacetum nubigenum (2n = 36) have been counted chromosomally for the first time at the world level. Besides, Koelpinia linearis (2n = 36), Ajania fruticulosa (2n = 18), Crepis flexuosa (2n = 14), and Tanacetum gracile (2n = 18) have been analyzed chromosomally for the first time from India. New intraspecific diploid/polyploid cytotypes are added for Artemisia desertorum (2n = 6x = 54), Carduus nutans (2n = 4x = 16), Erigeron annuus (2n = 2x = 18), Leontopodium jacotianum (2n = 4x = 48), Pentanema indicum (2n = 6x = 54), Scorzonera virgata (2n = 2x = 16), and Tragopogon pratensis (2n = 2x = 12). Besides, eight species have been evaluated cytologically for the first time from Kashmir Himalayas. Various meiotic abnormalities like cytomixis, structural heterozygosity, chromatin stickiness, nonsynchronous disjunction, laggards, bridges, unoriented chromosomes leading to pollen sterility have been observed for the first time in some species. The presence of B-chromosomes has been detected in Achillea millefolium (2n = 18+0-1B) and Saussurea candolleana (2n = 26+0-1B). Among meiotically analyzed species, diploids (76.5%) and polyploids (23.5%) prevail.
显示更多 [+] 显示较少 [-]