MITOTIC INSTABILITIES IN TETRAPLOID, HEXAPLOID, AND OCTOPLOID BROMUS INERMIS

Abstract

Mitotic irregularities were observed in the root tip cells at three ploidies, tetraploid (4x), hexaploid (6x), and octoploid (8x), of smooth bromegrass (Bromus inermis Leyss.). These included endomitosis, fragments, chromosomes excluded from the spindle, anaphase bridges, laggards and micronuclei, at different stages of mitosis. High frequencies of anaphase irregularities were detected at the 4x and 6x levels. The commercial octoploid was more stable. Intraplant variations of some morphological characters in smooth bromegrass may be attributed to chromosomal instabilities in somatic cells.