Chromosome Study In Five Endemic Kniphofia Species (asphodelaceae) Of Ethiopia

The karyotype of five endemic Kniphofia species of Ethiopia were studied. The studied speciesrnare: K. foliosa, K. schimperi, K. hildebrandtii, K. isoetifolia, and K. insignis. Somaticrnchromosomes were prepared from the root tip meristem using colchicines, 8-hydroxyquinolinernor ice-cold pretreatment, followed by fixation (3:1, ethanol:acetic acid) and then enzymernmaceration in pectinase-cellulase solution at 37°C for about 1 hr. Air-dry slides were preparedrnand stained in Giemsa stain in Sorensons phosphate buffer (pH = 6.8). The karyotype analysisrnhas shown that K. foliosa, K. schimperi, K. hildebrandtii and K. isoetifolia are diploid with 2n =rn12, where as K. insignis has 2n = 22 chromosomes which is assumed to be a polyploid on thernbasis of x = 6 for the genus. Polyploidy is the first report for the species. Morphologically, thernchromosomes showed a gradual decrease in size in all the species with only small differencesrnbetween the longest and the shortest chromosomes of each species. The size differences arernrelatively more pronounced in K. insignis. The karyotype formula was found to be 2m + 8sm+rn2st in K. foliosa, K. schimperi and K. hildebrandtii; 2m + 2m/sm + 8sm for K. isoetifolia andrn4m + 12sm + 1sm/st + 5st for K. insignis. Generally, there is only a minor degree ofrndifferentiation observed among the karyotypes of the diploid species. One pair of smallrnsatellites were observed on the tip of short arms in K. foliosa and K. hildebrandtii, two pairs inrnK. schimperii and K. isoetifolia and in K. insignis, the secondary constriction is located in thernmiddle of the long arm of a pair of chromosomes and thus delineated two large satellites.rnKniphofia foliosa from ‘Laga Shore’, about 10 kms from Gedo town, west of Addis Ababa,rnwas found to have a B-chromosome. This is the first report of B-chromosome for the species asrnwell as the genus. In spite of the fact that samples were collected from only a limitedrnnumber of sites, the cytogenetical information reported here would create only the basisrnfor further cytological investigation of Kniphofia species. It is, thus, recommended thatrnfurther cytological and molecular studies including specimens from a wider geographicrnarea should be carried out.rnKey words: B-chromosome, Chromosome, Endemic Kniphofia species, Ethiopia,rnKaryotype, Polyploidy.

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