Cytological aberrations in maize populations exhibiting unusual recombinational behaviour.

Earlier studies identified higher recombinational activity and increased somatic instability at various loci in the F1 and F2 progeny of particular stocks of a maize inbred line, A188. Hypothesizing that this may reflect a genome-wide perturbation of chromosome structure which would be detectable cytologically, aberrant meiotic behaviour in these stocks was investigated. Microsporocytes from a population of F2 plants derived from these stocks displayed the following aberrations: varying frequencies of metaphase and anaphase laggards, 'stickiness' at anaphase I resulting in chromosome bridges from pole to pole, acentric fragments and a spontaneous translocation of the NOR on chromosome 6. The frequencies of metaphase I and anaphase I abnormalities in these stocks were higher to a statistically significant extent than in control F2 populations, suggesting that these aberrations may be related to the unusual genetic behaviour of these stocks.