A New Record of Chromosome Count for Costus pictus D. Don

Abstract

The present cytological account presents a newly detected dysploid cytotype for Costus pictus with a chromosome number of 2n=4x=28. The present finding is the first report of meiotic chromosome count for the species. Analysis of microsporogenesis reveals abnormal meiotic behavior in pollen mother cells as manifested by the presence of interbivalent connections, un-oriented bivalents, chromatin stickiness, and laggards. An abnormal meiotic course in analyzed plants seems to be responsible for the formation of sterile pollen grains (31.96%). The study proposes that x=7 may have arisen due to descending dysploidy from x=9 and, the present specimen being an introduced species for the region may be evolving for better compatibility with the new habitat.