Cytogenetic Studies in Lilium callosum

III. Preferential Segregation of a Supernumerary Chromosome in EMCs

Abstract

The supernumerary chromosomes f_l in 2n=24+1f_l plants of Lilium callosum were found lying on the micropylar side (63.7%), on the chalazal side (13.0%), and on the MI plate (23.2%) at MI in EMCs, the disposition of f_l univalent not being a random one. If the f_l outside the MI plate passes undivided to the closer pole and the f_l on the MI plate passes to either pole, micropylar or chalazal, with equal chance, at least 75.4 per cent of micropylar nuclei will include 1f_l. Actually, at AI, MII, AII, the post-meiotic 1st and 2nd divisions, 80.0 per cent of the micropylar nuclei showed n=12+1f_l. This value coincides exactly with the result of the progeny analysis of the cross (24+1f_l)×(24) which gave 2n=24+1f_l and 2n=24 in an approximate proportion of 80:20 in percentage.