GENETIC-VARIATION IN HAWORTHIA-PUMILA AND HAWORTHIA-HERBACEA

Horizontal starch gel electrophoresis was used to examine genetic dive rsity within and differences between one population each of two morpho logically different species of Haworthia, namely H. pumila and H. herb acea. Twenty-five leaf samples of each species were surveyed for 24 pr oteins of which 13 were useful for routine analysis, and gene products of 16 protein coding loci revealed genetic variation at 7 (43.8%) the reof in both species. Values of 1.63 (+/- 0.20) and 1.56 (+/- 0.18) we re obtained for the mean number of alleles per locus and the average h eterozygosity per locus was calculated at 0.168 (+/- 0.058) and 0.144 (+/- 0.048) for H. herbacea and H. pumila respectively. The malate deh ydrogenase-a locus is a potential genetic marker to identify the speci es studied electrophoretically. The mean genotypic distance index betw een the populations studied was 0.184, an indication of a large degree of differentiation between the species. These values are much higher than values obtained for other members of the Aloaceae, showing that n ormal levels of genetic variation can be expected in at least some suc culent monocotyledons.