Abstract
Presently, A. millefolium, a morphogenetically variable species, has been scored from phytogeographically isolated and unexplored areas of the northwest Himalayas for chromosome counts and male meiotic course. All the studied accessions shared the same meiotic chromosome number of n = 9 and existed at diploid level. A majority of the accessions exhibited the normal meiotic course including microsporogenesis and almost cent per cent pollen fertility. However, three accessions scored from Sangla Valley (Chittkul, 3450 m) and Solang Valley (Dhundi, 3000 m and Palchan, 2480 m) showed the presence of multiple associations of chromosomes in PMCs (pollen mother cells). The quadrivalents formed as a consequence to reciprocal translocations are either chain or ring type (typical ring and zigzag). Meiocytes with multivalents depicted relatively higher chiasma frequency than those with normal bivalent formation. In 4.77% of PMCs, chromosomes remained as laggards during anaphase-I and organized into micronuclei during sporad formation. Consequently sterile/unstained pollen grains were observed. This is the first report of structural heterozygosity for reciprocal translocations in the species.
