| T. monococcum chromosomes showed a few C-bands (Fig.
1a & b). These C-bands located mainly in centromere and telomere regions
of the chromosomes, and were allocated tentatively to each chromosomes.
Characteristics of C-banding patterns of T. monococcum chromosomes
was telomere bands in comparison with those of Ae. speltoides chromosomes
(Fig. 1c & d). KOSTOFF (1938) stained T. monococcum
chromosomes by gentian violet, and reported that T. monococcum chromosomes
had heterochromatic segments at the distal ends. The present results agree
with his observation although he did not detected centromere heterochromatin.
Ae. speltoides chromosomes had more C-bands in comparison with T. monococcum chromosomes, especially in intercalary regions of the chromosomes (Fig. 1c & d). GILL and KIMBER (1974B), and GUSTAFSON and KROLOW (1978) reported that C-band patterns of T. aestivum cv. Chinese Spring and T. turgidum cv. '20' chromosomes, respectively. GUSTAFSON and KROLOW (1978) indicated that C-banding patterns of A- and B- genomes chromosomes of T. turgidum cv. '20' were similar to those of T. aestivum cv. Chinese Spring. When the present results of C-banding patterns of T. monococcum and Ae. speltoides chromosomes are compared with the results of GILL and KIMBER (1974) and GUTSTAFSON and KROLOW (1978), it appears that the banding patterns of several chromosomes of T. monococcum and Ae. speltoides are corresponding with those of A- and B- genomes chromosomes of T. aestivum cv. Chinese Spring and T. turgidum cv. '20'. Further studies of C-banding patterns of other Aegilops species chromosomes will provide informations on the evolution of wheat and origin of B genome. Literature Cited DARVEY, N.L., & J.P. GUSTAFSON 1975. Identification of rye chromosomes in wheat-rye addition lines and triticale by heterochromtin bands. Crop Sci. 15: 239-243. GILL, B.S. & G. KIMBER 1974a. Giemsa C-banding technique for cereal chromosomes. Cereal Res. Comm. 2: 87-94. GILL, B.S. and G. KIMBER 1974b. Giemsa C-banding and the evolution of wheat. Proc. Nat. Acad. Sci. 71: 4086-4090. GUSTAFSON, J.P. & K.D. KROLOW 1978. A tentative identification of chromosomes present in tetraploid triticale based on heterochromatic banding patterns. Can J. Genet. Cytol. 20: 199-204. HADLACZKY, Gy & L. KALMAN 1975. Descrimination of homologous chromosomes of maize with Giemsa staining. Heredity 35: 371-374. KOSTOFF, D. 1938. Heterochromatin, somatic "crossing over" and the interchange hypothesis between non-homologous chromosomes. Proc. Indian Acad. Sci. 8: 11-44. KURATA, N. & T. OMURA 1978. Karyotype analysis in rice. I. A new method for identifying all chromosomes pairs. Jap. J. Genet. 53: 251-255. LINDE-LAURSEN, I. 1975. Giemsa C-banding of chromosomes of "Emir" barley. Hereditas 81: 285- 289. NODA, K. & K.J. KASHA 1978. A modified Giemsa C-banding technique for Hordeum species. Stain Tcch. 53: 155-162. SARMA, N.P. and AT. NATARAJAN 1973. Identification of heterochromatic regions in the chromosomes of rye. Hereditas 73: 233-238. SUMNER, A.T. 1972. A simple technique for demonstrating centromeric heterochromatin. Exptl. Cell Res. 75: 304-306. |
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