PRODUCTION AND IDENTIFICATION OF NEW STRUCTURAL CHROMOSOME MUTATIONS IN BARLEY (HORDEUM-VULGARE L)

A total of 52 reciprocal translocations and 9 pericentric inversions w ere induced and identified in both standard and cytologically marked b arley karyotypes using gamma-rays as the clastogenic agent. An analysi s based upon Giemsa N-banding patterns and arm length measurements of the reconstructed chromosomes enabled a rather precise cytological loc alization of intra- and interchange breakpoints. This analysis was sig nificantly facilitated and improved, especially for the identification of pericentric inversions, when the reconstructed karyotype T-1586 wa s used as starting material. The majority, if not all, of the aberrati on breakpoints proved to be localized in interband regions or in media l and terminal parts of the chromosomes, i.e., in regions which are de ficient in constitutive heterochromatin. A great number of the structu ral mutations produced in this study contain specific cytological mark ers covering nearly all of the chromosomes of barley karyotype. This m aterial might be of considerable interest in solving various problems of barley cytogenetics and chromosome engineering and especially in co nstructing a physical map of barley genome.