EN
The distribution of heterochromatin in mitotic chromosomes was studied in five inbred lines of rye Secale vavilovii Grossh. (nos. 52, 109, 116, 121 and 225). An additional heterochromatin band was found on the long arm of one of the chromosomes of pair 2R, at an average distance of 2.08 µm from the centromere. After the plants with an additional band on 2R were reproduced, plants with two chromosomes with an additional band were obtained, as well as those with one chromosome with an additional band and with chromosomes without that band. Distinct differences were observed in 1R in terms of the presence/absence of a band in the vicinity of the NOR constriction, and the size of the telomere bands. Telomere band size also differed in chromosomes 2R, 4R, 6R and 7R. Modifications of the heterochromatin fragment consisted in deletion of a telomeric heterochromatin segment and in the presence of different numbers of interstitial heterochromatin bands. The content of telomeric heterochromatin was the highest in 3R (18.86%) and the lowest in 4R (6.90%). During telophase, daughter nuclei connections in the form of a chromatin bridge were observed in a number of cells.