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GIEMSA N- BANDING PATTERN IN SOME WILD DIPLOID SPECIES OF HORDEUM

BUSHREEN JAHAN AND AHSAN A. VAHIDY^*

Abstract: Distribution pattern of constitutive heterochromatin in some wild diploid Hordeum species was studied by Giemsa N-banding technique. It was possible to discriminate between the species by the number and morphology of the nucleolar chromosomes and the presence or absence of certain characteristic N-bands on chromosomes. An ideogram was developed for each studied species/taxa of Hordeum for the description of individual N-bands. The banding patterns, especially the finer intercalary and distal bands were more easily observed and reliably scored in late prophase and early metaphases when the chromosomes are at the right stage of contraction. N-banding procedure indicated that a clearly detectable mass of constitutive heterochromatin was located at the centromeric and interstitial regions of most chromosomes; however a wide variation in the intensities of bands, number of bands and their position in the chromosomes were observed.  Among a mean number of bands 0.63 centromeric, 0.17 telomeric, 0.50 intercalary and 0.14 were found on satellites of diploid Hordeum species.

Department of Botany,Federal Urdu University of Arts, Sci. & Technology, Gulshan-e-Iqbal Campus, Karachi-75300, Pakistan.