NEW TRANSLOCATION IN BARLEY RESULTING IN A CYTOLOGICALLY MARKED KARYOTYPE

The development of synthetic karyotypes of barley with easily distinguishable chromosome pairs that may be used in investigations of the regional specificity of mutagenic factors is desired. The chromosomal mutant T-1586 proved to be a suitable subject to study the inter- and intrachromosomal distribution of induced aberrations and related problems. It was produced by .gamma. irradiation of dry seeds of the barley variety ''Freya''. Detailed analysis of data shows that the karyotype of T-1586 is probably a reciprocal translocation between chromosome 1 and chromosome 4 (according to Burnham and Hagberg''s designation). Besides its use in studies of mutagenic specificity on the chromosome level, T-1586 deserves interest in another respect. Recently, it was revealed that chromosome 1 is not the longest chromosome in the normal karyotype, and a new designation of barley chromosomes was proposed. Thus, it may be found that chromosomes 2 and 4 are involved when a test with a translocation tester set is made. Because of the specificity of the structural changes induced, the translocation line T-1586 may be a useful material for elucidation of this question, and further studies in this respect are in progress.