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chromasomal aberrations in maize regeneranh, 96% of which involved st~ctwo~ changes like
interchanges (4r/.), deficiencies (35%) and heterowphic pairs (19%). They also obswved
48% of plants from 8-9 months old cultures to cany a chromosome aberration while ail plants
from 3-4 month old cultures were cytogeneticaily normal.
In Ofyza safivo (rice) Balal et al. (1980a) observed aneuploids and polypioids in hiplaid plants
derived from immature and mature embryo callus. In 100 R2 lines screened by Nowick et d.
(1988) a low percentage of anaphase bridges were 0bse~ed. This chromosomal abnwmality
was non-segregating in the R2 with low variances, although individual plants ouhide the range
of 'Lemont' were seen to be variant among the R2 progenies.
In Triticale Jordan and Latter (1985) observed extreme chromosomal instability in one
genotype R,, with both the rye and wheat univaienh at metaphase I.
In Apium graveolens (celery), Otton (1983) observed hypodiploid and a mixlure of diploid and
hypodiplaid and also pdyploid cells in callus cultures. Some of the plants regenerated Via
somatic embryogenesis were monosamic. Karyotypic analytis of a clone showed Me
presence of a large metacentric chromosome.
Cytological instabilf in Medicago was reported by Groose and Bingham (1984) In plants
regenerated from callus cultures. 11% of regenerants lost one or more chromosomes thus
showing a chromosome number ot 28 to 31. Two apparent shmt to octopioids were also
observed and approxlmatdy 60% of variant regeneranh exhiblted a change In chromasame
number. They aitdbuted the considerable variability In feMlW and morphology to changes in
chromosome number. Saunden and Blngham (1972) observed 5 of 166 alfalfa plants dwlved
from anthers and 4 of 60 plant$ derived lrom ovaries to be octopldd. Hattman et al. (1984cr),