Genetic induction of structural changes in barley chromo- somes added to common wheat by a gametocidal chromosome derived from Aegilops cylindrica

A gametocidal chromosome, chromosome 2C derived from Aegilops cylindrica, was introduced into six wheat-barley addition lines to establish chromosome-mutationinducing lines. These lines, except the one for chromosome 4H, had a pair of respective barley chromosomes and one 2C chromosome (22”+1’); the line for 4H was doubly monosomic for chromosome 4H and chromosome 2C (21”+2’). In these lines, chromosome breaks were expected to occur in the gametes lacking chromosome 2C. The selfed and backcrossed progeny of these lines were cytologically investigated by in situ hybridization and N-banding. Various types of structural aberration like deletion and translocation were detected for all barley chromosomes with frequencies ranging from 10.8% to 27.9%. The highest frequency of aberrations occurred in chromosome 4H with most of the breakpoints localized in or near the centromeric region. A simplified procedure of in situ hybridization used in this study was suitable for the large-scale screening for barley chromosome aberrations in the background of wheat.