Cytogenetics of polyploids

Abstract

Artemisia maritima growing in Gurez (Kashmir) has been studied cytologically and is a tetraploid with 2n=36. The microspore meiosis is characterised by asynapsis, complement fractionation, nondisjunction of chromosomes, univalency and occurrence of restitution nuclei. There is an upset in timing relations of meiosis resulting in an aberrant meiosis which has been described fully. The initial movement of the chromosomes towards poles at Al is reversed towards the equator and a restitution nucleus is formed. A wall is secreted by such a P. M. C. and this assumes the appearance of a pollen grain. Although interesting irregularities were observed in 1st division of meiosis, the post-restitution division is comparatively regular. It is suggested that this tetraploid has originated as a result of wide hybridization and is thus an allopolyploid. © 1965, Japan Mendel Society, International Society of Cytology. All rights reserved.