| The variation was significant as regards the mutants belonging to group
II, and it proved to be associated with concrete phenotypic differences.
It chiefly concerned: 1) bands 4 and 9 of shoot esterase patterns and 2)
and 3 of the coleoptile esterase pattern (Fig. 2).
In detail, mutant S3 revealed the typical electrophoretic spectrum of m2
(parental type) and, in addition, the fast band 9 (found in m1 and all mutants,
apart S5). Besides, as regards shoot peroxidase zymogram, mutant S3 was
exceptional in lacking the slow band 3, which was identified in both varieties
and in all other mutants. Mutant S4, the awned derivative of the awnless m2 separated 1) in shoot esterase pattern, the zones 4 and 9, lacking from m2, but present in m1, 2) in coleoptile esterase spectrum the slow zone 3, also typical for m1. On the contrary, mutant S5, the awnless derivative of the awned m1 lacked bands 4 and 9 of shoot esterase patttens (Fig. 2) as well as band 3 of the coleoptile zymogram. This absence was characteristic of m2. Therefore the three bands seem to be phenotypically associated with awning, having been recognised in m1 and all awned mutants, yet not all separating either in m2 or in the awnless mutants S3 and S5. The results provided by meiotic and electrophoretic analysis lead to the conclusion that the diverging mutants S3, S4 and S5 represent situations in which irradiation had mostly affected genes controlling awn character. Such genes had been recognised to locate in chromosome arms 4BS (Hd), 5AL (B1) and 6BL (B2), so that epistatic interaction between them or between each of them and various promoter genes can result to the appearance of awns (McIntosh 1973). Literature Cited COUCOLI, H. and E. SKORDA, 1966. Further evidence on the karyotype of Triticum monococcum L. and Triticum durum Desf. Can. I. Gen. Cytol. 8, 102-110 HAIR, J.B., and G.M. WRIGHT 1968 Analysis of a compactoid wheat. Abst. 3rd Intern. Wheat Gen. Symp., Canberra, 324-326 KUCKUCK, H., 1959. Neuere Arbeiten zur Entstehung der hexaploiden Kulturweizen. Pflanzenzucht. 41, 205-226 MAC KEY, J., 1954. Neutron and X-ray experiments in wheat and a revision of the speltoid problem. Hereditas 40, 65-180 MCINTOSH, R.A., 1973. Gene symbols in wheat. 4th Intern. Wheat Gen. Symp.. Missouri, 893-937 MITRA, R., and C.R. BHATIA, 1971. Isozymes and polyploidy. I. Qualitative and quantitative isozyme studies in the Triticinae. Gen. Res. Cambr. 18, 57-69 MURAMATSU, M., 1963. Dosage effect of the spelta gene q of hexaploid wheat. Genetics 48, 469-482 SEARS, E.R., 1944. Cytogenetic studies with polyploid species of Wheat. II Additional chromosome aberrations in Triticum vulgare. Genetics 29, 232-246 SEARS, E.K., 1956. The systematics, cytology and genetics of wheat. Handb. Pflanzenzucht, Second edition 2, 164-187 SEARS, E.R., 1975. The wheats and their relatives. Handb. of Genetics 2, 59-91. Plenum Press SINGH, M.P., 1968. Some radiation induced changes at Q locus in bread wheat. Caryologia 22, 119-126 SKORDA, E. 1971. The mutability of some Greek varieties of the genus Triticum. Ph. D. thesis, Athens 1971 |
| <-- Back |