II.15 Giemsa banding of barley chromosomes.
Ib Linde-Laursen, Danish Atomic Energy Commission, Research Establishment Risø, DK-4000 Roskilde, Denmark.
Some of the barley chromosomes are not readily identifiable with the conventional cytological methods. The application of fluorochromes or Giemsa stain to differently treated meristems of a number of plant species has resulted in chromosome banding patterns, which have facilitated the identification of the chromosomes. The methods reveal differences in chromosome structure, which to some degree are identical with the differentiation in euchromatin and heterochromatin. The chromosomes of barley contain very limited amounts of heterochromatin and are therefore not an obvious material for the application of the banding methods. However, in combination with our current attempts to improve the linkage maps of some of the barley chromosomes (cf. Søgaard 1974a and b, Jensen 1975, Jensen and Jørgensen 1975a and b, Jørgensen 1974) the establishment of cytological maps of the barley chromosomes based on the Giemsa method has been initiated.
We have tried a range of Giemsa techniques. Some have consistently revealed bands at the centromeres of all seven chromosomes and at the nucleolus organizer regions in the short arms of the two satellited chromosomes. Now and then faint intercalary bands have been observed in at least five chromosomes. The presence of these renders the establishment of a cytological map of use for the identification of the barley chromosomes likely.
Literature cited:
Jensen, J., Jørgensen, J. H. 1975a and b. Hereditas (in press).
Jensen, J. 1975. Coordinator's report: Chromosome 5. BGN 5: 73-75, 1975.
Jørgensen, J. Helms. Localization of the ml-o locus on barley chromosome 4. BGN 4: 43-44, 1974.
Søgaard, Bodil. The localization of eceriferum loci in barley. III. Three point tests of genes on chromosome 1 in barley. Hereditas 76: 41-48, 1974a.
Søgaard, B. Three point tests on chromosomes 1 and 7. BGN 4: 70-73, 1974b.