ABSTRACT
Chromosomal aberrations are a common occurrence in cell and tissue culture-derived calluses and their regenerates. In general, numerical and structural changes in chromosomes are attributed to spindle failure that causes endoreduplication, c-mitosis, nuclear fragmentation (amitosis), multipolar congurations, and lagging chromosomes. These changes are induced by (1) media composition, (2) age of the callus, (3) nature of the callus, morphogenic versus nonmorphogenic, (4) genetic background of the explants, and (5) kinds of media, solid versus liquid (Bayliss, 1973, 1980; Evans and Reed, 1981; Wersuhn and Dathe, 1983; D’Amato, 1985; Ogura, 1990; Greier, 1991).
