Chromosome counts, chromosomal pairing, and pollen fertility in thirty-eight species of Asteraceae from Pangi Valley in District Chamba of Himachal Pradesh (India)

Abstract

The current investigation includes detailed male meiotic studies, chromosomal counts, and pollen fertility on 38 species of family Asteraceae from the Pangi Valley, a part of cold desert Himalayas. The first-ever chromosome counts have been made for seven species viz. Aster albescens Wall. (n = 9), A. heterochaeta C. B. Clark (n = 9), Cirsium involucratum DC. (n = 34), Inula obtusifolia Kern. (n = 8), Saussurea piptathera Edgew. (n = 13), Senecio arnicoides (DC.) C. B. Clark, and Tanacetum robustum Hook f. et Thoms. (n = 9). Besides, new cytotypes are reported for Aster flaccidus Bunge (2n = 2x = 18), A. peduncularis Wall. ex Nees (2n = 2x = 18), and Youngia tenuifolia (Willd.) Babcock & Stebbbins (2n = 4x = 20). Out of the thirty-eight species, six species viz. Crepis multicaulis Ledeb., C. sancta (L.) Babcock, Erigeron multiradiatus (Lindl.) C. B. Clark, Scorzonera divaricata DC., S. arnicoides (DC.) C. B. Clark, and Taraxacum officinale Wigg., showed a number of meiotic abnormalities leading to reduction in pollen fertility and production of heterogeneous-sized pollen grains. The triploid cytotype of T. officinale Wigg. (2n = 24) depicted irregular meiotic course characterized by the presence of high frequency of univalents, abnormal sporads, and pollen malformation. B-chromosome has been reported for the first time in some individuals of S. arnicoides (DC.) C. B. Clark. Compiled information on the worked out species reveals the existence of considerable amount of chromosomal variations in some species involving the role of aneuploidy and polyploidy.