CHARACTERIZATION OF DELETIONS IN COMMON WHEAT INDUCED BY AN AEGILOPS CYLINDRICA CHROMOSOME - DETECTION OF MULTIPLE CHROMOSOME REARRANGEMENTS

An Aegilops cylindrica chromosome induces terminal deletions of chromo somes in wheat as identified by C-banding. We are constructing high-de nsity physical maps of wheat chromosomes and have detected additional chromosome rearrangements. Among 63 lines with chromosomal subarm dele tions in group 7 chromosomes, 7 lines (11.1%) were shown to harbor add itional chromosome rearrangements. Two other lines were also omitted f rom the physical mapping because of the nature of the breakpoint calcu lations. The presence or absence of chrome some-specific restriction f ragment length polymorphism (RFLP) or random amplified polymorphic DNA (RAPD) markers indicated that additional interstitial deletions are p resent in 3 lines (4.8%) with deletions in the short chromosome arms a nd in 4 lines (6.3%) with deletions in the long chromosome arms. We al so used chromosome pairing analysis of F-1 plants of deletion lines wi th double ditelosomic lines of 'Chinese Spring' wheat to detect small terminal deletions. The deletion of the most distal 1% of chromosome a rm 7AL was associated with a pairing reduction of 60%.