DIRKS, V. A., J. G. ROSS and D. D. HARPSTEAD: Colchicine-induced true-breeding chimeral sectors in flax. J. Hered. 47(5): 229–233 (1956).
FRANZKE, C. J., and J. G. ROSS: Colchicine induced variants in Sorghum. J. Hered. 43(3): 107–115 (1952).
FRANZKE, C. J., M. E. SANDERS and J. G. ROSS: Influence of light from an infra-red bulb on the mutagenic effect of colchicine on Sorghum. Nature (Lond.)188, 242–243 (1960).
ROSS, J. G.: Proof of somatic reduction after colchicine treatment using marked chromosomes. Manitoba Med. Rev. 42, 536–539 (1962).
ROSS, J. G., A. E. FOSTER and C. J. FRANZKE: Identity of a mutated gene for strong awns in a colchicine induced true-breeding mutant in Sorghum. Crop Sci. 1, 156 (1961).
ROSS, J. G., C. J. FRANZKE and L. O. SCHUH: Studies on colchicine-induced variants in Sorghum. Agron. J. 46, 10–15 (1954).
THE possible value of somatic reduction as a tool in the hands of the plant breeder was pointed out by Huskins (5) in 1948. Franzke and Ross (3) attributed the occurrence of variants obtained in sorghum following colchicine treatment to this phenomenon of somatic reductions. The variant plants had the same chromosome number as their untreated full sibs and gave progenies which bred true. This study deals with measurements and observations of characteristics of agronomic importance made on progenies from treated and untreated full sibs of a true breeding variety of sorghum.
SANDERS, M. F., and C. J. FRANZKE: Somatic reduction of tetraploid Sorghum to diploid mutants following colchicine treatment. Nature (Lond.) 196: 696–698 (1962).
COLCHICINE treatment of seedlings of certain sorghum lines has resulted not only in the expected polyploids, but also in diploid plants which are mutant for many characters. Some of these diploid mutants breed true immediately while others give segregating progenies1–3. The original hypothesis to explain their appearance suggested that a somatic reduction of the chromosomes (similar to that observed by Huskins4) occurred and was followed by duplication. These mechanisms could result in the concentration of chromatin from ancestors of a putative allopolyploid. However, investigations have produced either no or little cytological evidence for duplication or relocation of chromatin5,6. In addition, mutant characters which have been studied have shown Mendelian inheritance7–10. The alternative hypothesis was then proposed that, in addition to a balanced somatic reduction of the chromosomes after application of colchicine, mutations at many loci also occurred prior to duplication back to the diploid number.
SNOAD, B.: Somatic instability of chromosome number in Hymenocallis calathinum. Heredity 9(1): 129–134 (1955).
WILSON, G. B., and K. C. CHENG: Segregation and reduction in somatic tissues II. The separation of homologous chromosomes in Trillium species. J. Hered. 40(1): 3–6 (1949).
TREATMENT with solutions of sodium nucleate of tissues undergoing mitosis induces, amongst other departures from normal, a certain number of reduction type divisions as reported by Huskins.2,3 Reduction-divisions have also been found in Allium root tips after treatment with phosphates (Galinsky, unpub.) as well as in untreated roots from onions which have been stored for several months and in untreated Trillium root tips near the end of their root formation period.