Karyotypic Variation among Somaclonal Variants of Caladium (Caladium ×hortulanum)

Plants regenerated from cell and tissue culture often display changes in morphology or other aspects, and such changes have been referred to as somaclonal variation. Somaclonal variants have been reported in caladium and a number of other aroids, but few of these variants have been characterized at the chromosome level. Recently we discovered 24 somaclonal variants among plants regenerated from leaf segment cultures of ‘Red Flash’ caladium, and here we report karyotypic changes among 18 of the ‘Red Flash’ somaclonal variants in comparison to the wildtype. Wildtype ‘Red Flash’ caladium contains 15 pairs of chromosomes, including 20 metacentric chromosomes, four submetacentric chromosomes, and six subtelomeric chromosomes (2n = 2x = 20m + 4sm + 6st). Results showed that Chromosomes 4, 7, 11, 12, and 13 of ‘Red Flash’ were relatively stable, and none of the variants appeared to show structural or numerical changes on these chromosomes. Chromosome gains were observed for Chromosome 1, 9, 14, or 15 at a frequency of 5.6%. Chromosome losses were seen for Chromosome 1, 2, 3, 5, 6, 8, or 15, at a frequency from 5.6% (Chromosome 5 or 8) to 50.0% (Chromosome 2). New karyotypes appeared in seven variants were probably due to chromosome structural rearrangements.