Studies on the Occurrence, Cytology, Fertility and Breeding Behaviour of Aneuploids in Induced Autotetraploid Job's Tears

Abstract

In the progenies of autotetraploid (4n=40) Job's tears, aneuploids with 39 and 41 chromosomes occurred in some proportion. Non-recovery of aneuploids having less than 39 or more than 41 chromosomes was attributed to embryo abortion. The 39-chromosome plants regularly formed a trivalent or univalent in a cell and the 41-chromosome plants showed a pentavalent in a proportion of cells. Both aneuploid classes were less fertile than 40-chromosome plants. Much of the sterility in both aneuploids and euploids seemed to be genetic. Open pollinated progenies of 39 and 41-chromosome plants did not show chromosome numbers beyond the 39-41 range and a great majority of these exhibited an euploid number of 40.