Figure 6.

Summary of Chromosomal Aberrations Observed.

The types of chromosomal aberrations recognized are shown. Key to the chromosomal features is at the right. After pollen irradiation and screening of the immediate F1 seedlings, multiple types of aberrations were found with special emphasis on centromeric changes (Table 1). Dicentric and multicentric chromosomes were observed as well as acentric fragments. Dicentric chromosomes with a single primary constriction are candidates for centromere inactivation. Acentric fragments that are inherited are candidate chromosomes with de novo centromeres. Additional chromosomal types included various sizes of minichromosomal fragments with centromeres of various sizes, an isochromosome, and ring chromosomes.