Resumo
The methods used in obtaining polyploid cassava (Manihot utilissima Pohl) by colchicine treatment were described in detail. Two solutions of colchicine were tried, one at 0.5% and other at 1.0%, both giving identical results in producing many altered plants. The chromosome number of the altered plants was determined and [a correlation between chromosome duplication and increase of the major diameter of stomata was found. Size of stomata in cassava serves to identify poliploids individuals if the plant produced by treatment is not a chimera, a very frequent event in producing polyploid cassava by colchicine. It was emphasized that the plants obtained by treatment were a type of chimera, with the aerial part polyploid and the subterranean base diploid. The development of polyploid individuals obtained from the polyploid aerial part of the treated was analyzed. A comparison between the tetraploid and the diploid control plants was made, the octoploid plant being too slow in development. There are many groups of polivalents in the first meiotic metaphase of the autopoly-ploid individuals obtained. By an analysis of the polen grains it was assumed that the diploid plant may be a structural hybrid. The production of the tetraploid plants was computed preliminarly, other detailed experiments involving spacing being necessary for estimating the commercial production,, since the diploid produces more branched plants than the tetraploid ones.
Tratamento de mandioca pela colchicina II. Formas poliplóides obtidas
E. A. Graner (* (* ) Da Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo. )
SUMMARY
The methods used in obtaining polyploid cassava (Manihot utilissima Pohl) by colchicine treatment were described in detail. Two solutions of colchicine were tried, one at 0.5% and other at 1.0%, both giving identical results in producing many altered plants.
The chromosome number of the altered plants was determined and [a correlation between chromosome duplication and increase of the major diameter of stomata was found. Size of stomata in cassava serves to identify poliploids individuals if the plant produced by treatment is not a chimera, a very frequent event in producing polyploid cassava by colchicine.
It was emphasized that the plants obtained by treatment were a type of chimera, with the aerial part polyploid and the subterranean base diploid. The development of polyploid individuals obtained from the polyploid aerial part of the treated was analyzed. A comparison between the tetraploid and the diploid control plants was made, the octoploid plant being too slow in development.
There are many groups of polivalents in the first meiotic metaphase of the autopoly-ploid individuals obtained. By an analysis of the polen grains it was assumed that the diploid plant may be a structural hybrid.
The production of the tetraploid plants was computed preliminarly, other detailed experiments involving spacing being necessary for estimating the commercial production,, since the diploid produces more branched plants than the tetraploid ones.
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LITERATURA CITADA
- 1. Blakeslee, A. F. e A. G. Avery. Methods of inducing chromosomes in plants by treatment with colchicine. Journal of Heredity 28: 393-411. 1937.
- 2. Graner, E. A. Contribuição para o estudo citológico da mandioca. Publicação da Escola Superior de Agricultura l,Luiz de Queiroz", pgs. 128, Figs. 67, Piracicaba, 1935.
- 3. Graner, E. A. Quimera cromosômica na mandioca. Publicação da Escola Superior de Agricultura "Luiz de Queiroz", pgs. 1-13, Figs. 4, Piracicaba, 1935.
- 4. Graner, E. A. Tratamento de mandioca pela colchicina. I. Nota preliminar sobre poliploidia indicada pela diferença de tamanho dos estômatos. Jornal de Agronomia, 3: 83-98. 1940.
- 5. Graner, E. A. Polyploid cassava induced by colchicine treatment. Journal of Heredity 32: 281-288. Fig. 18-24. 1941.
- 6. Graner, E. A. Notas sobre o florescimento e frutificação da mandioca. Bragantia 2: 1-8. Fig. 1-6. 1942.
- 7. Graner, E. A. Genética de Manihot I. Hereditariedade da forma da folha e da coloração da película externa das raizes em M. utilissima Pohl. Bragantia 2: 13-19. Fig. 1-6. 1942.
Datas de Publicação
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Publicação nesta coleção
01 Jul 2010 -
Data do Fascículo
Fev 1942
