Cytogenetics of Polyploids

1. Cytology of polyploid Artemisia vulgaris

Abstract

Meiotic behaviour of the chromosomes of a tetraploid has been studied with the following objectives in Artemisia vulgaris;
1. To understand the nature of polyploidy involved and causes of seed sterility.
2. The interrelationship of aberrant chromosome movement, spindle organisation and microsporocyte divisions and their overall relation to the changed meiotic rates.
From the observations of abnormal meiotic behaviour source and limits of variability affecting fundamental processes of chromosome movement, reappointment and finally cell division have been studied. The material appears to be an autotetraploid. It has been concluded that it is the autopolyploidy that has contributed to meiotic instability because phenomena like nondisjunction and complement fractionation of chromosomes adding to their meiotic variability have been found. It is probable that the ployploids are untapped reservoirs of variability that can be drawn upon, to increase the meiotic instrability so as to induce variation at higher levels.