II. 23. A proposed revision of the barley karyotype.
K.J. Kasha and K. Noda. Crop Science Department, University of Guelph, Guelph, Ontario, Canada N1G 2W1. "R"
We wish to bring to the attention of barley researchers our proposal to revise the karyotype of barley. The evidence indicates that the karyotype described by Tjio and Hagberg (1951) and associated with the linkage groups as adopted by the North American Barley Research Workers Conference (Ramage et. al., 1961) is not correct for chromosomes 1, 2 and 3. In order to maintain the numbering of the linkage groups and trisomics as currently being used, we have proposed to change the order of the chromosomes in the karyotype. This proposal was submitted for publication and accepted to appear in Crop Science Vol. 18, No. 6, 1978, Noda and Kasha. It contains a key to identify the barley chromosomes associated with the currently numbered linkage groups. This key is based upon relative lengths, arm ratios, secondary constrictions and the Giemsa C-banding patterns of the chromosomes. As rearranged, chromosome 1 has the most median centromere, chromosome 2 is the longest chromosome and chromosome 3 has the smallest arm ratio (L/S). Chromosomes 4 to 7 remain unchanged. While C-banding patterns have been shown to vary a little from cultivar to cultivar (Linde-Laursen, 1978a), the basic banding pattern is consistent enough to permit identification of the barley chromosomes. Our banding pattern identification of chromosomes using trisomics is consistent with the multiple interchange identifications of Tuleen (1973) and Kunzel (1976) and the C-banding procedures of Linde-Laursen (1975, 1978a).
The C-banding pattern of telo-trisomics (Linde-Laursen, 1978b) should prove useful in orientating the linkage map on the chromosomes.
References:
Kunzel, G. 1976. Indications for a necessary revision of the barley karyogramme by use of translocations. pp. 275-281. In: Barley Genetics III. (Ed. H. Gaul) Karl Thiemig. München.
Linde-Laursen, I. 1975. Giemsa C-banding of the chromosomes of 'Emir' barley. Hereditas 81:285-289.
Linde-Laursen, I. 1978a. Giemsa C-banding of barley chromosomes. I. Banding pattern polymorphism. Hereditas 88:55-64.
Linde-Laursen, I. 1978b. Giemsa C-banding of barley chromosomes. II. Banding patterns of trisomics and telo-trisomics. Hereditas 89:37-41.
Noda, K. and K.J. Kasha. 1978. A modified Giemsa C-banding technique for Hordeum species. Stain Technology 53:155-162.
Ramage, R.T., C.R. Burnham and A. Hagberg. 1961. A summary of translocation studies in barley. Crop Sci. 1:277-279.
Tjio, J.H. and A. Hagberg. 1951. Cytological studies on some x-ray mutants of barley. Anales estac. Aula Dei 2:149-167.
Tuleen, N.A. 1973. Karyotype analysis of multiple translocation stocks of barley. Can. J. Genet. Cytol. 15:267-273.