CHROMOSOME CHARACTERIZATION OF THE CHROMOSOMES OF Clivia (AMARYLLIDACEAE) USING FLUORESCENCE IN SITU HYBRIDIZATION AND CHROMOSOME BANDING

¹ School of biological science, The university of Auckland, Private Bag 92019, Auckland. New Zealand.

² 488 C, Don Buck Road, Massey, Auckland 8, New Zealand

The genus Clivia is endemic to South Africa. Of the four species only C. miniata has been domesticated and is widely cultivated as an ornamental plant. Little work has been done on their genetics so we have been using a variety of techniques, including in situ hybridization, to characterize their chromosomes. All of the species are diploid with 2n=22, and have similar karyotypes. However, the mapping of the rRNA loci, both 26S rDNA and 5S rDNA, has revealed striking differences in the number and location of these genes. In C. nobilis there are three pairs of 26S rRNA hybridization sites, in C. miniata and C. caulescens there are two and in C. gardenii only a single site was seen. Using various chromosome banding techniques (Giemsa C-banding, DAPI and chromomycin banding) that allow the identification of all the chromosomes we can demonstrate that the location of the hybridization sites in the genomes is variable with no single chromosome pair having these genes in all species. In contrast, the 5S rRNA genes are found on the same chromosome pair and in the same position in all four species. Using these techniques it is now possible to identify the individual species from their chromosomes and to determine the parentage of unknown hybrid combinations.