Resumo
A type of leaf-roll has been noticed for many years in commercial tobacco plantings in the State of S. Paulo. Leaf-roll plants were supposed to be affected by a virus disease, but repeated attempts to transmit it by grafting, juice inoculation and by insect vectors failed consistently. Later studies showed that the leaf-roll condition is due to genetic factors and that probably more than a pair of recessive genes are involved in its transmission. Even after the genetic nature of the leaf-roll condition was definitely established, attempts were made to induce the leaf-roll condition in plants genetically normal by several methods : 1. Spraying their leaves with the juice from leaf-roll plants ; 2. Approach-grafting a leaf-roll scion onto a normal plant and vice-versa, following with defoliation, cutting back or shading of the normal graft component. This was done to stimulate translocation of the phloem contents from the leaf-roll scion or stock into the normal stock or scion respectively. It was thought that if leaf-roll were due to the genetically controlled production of a hormone-like substance, these treatments might induce the leaf-roll condition in plants genetically normal. The results, however, have been negative.
Um enrolamento das fôlhas do fumo de causa genética(1 (1 ) Trabalho apresentado à "Segunda Semana de Genética", realizada em fevereiro de 1949 na Escola Superior de Agricultura "Luiz de Queiroz", de Piracicaba, São Paulo. )
A. S. CostaI; R. ForsterII
IEngenheiro agrônomo. Secção de Genética
IIEngenheiro agrônomo, Subdivisão de Estações Experimentais. Instituto Agronômico de Campinas
SUMMARY
A type of leaf-roll has been noticed for many years in commercial tobacco plantings in the State of S. Paulo. Leaf-roll plants were supposed to be affected by a virus disease, but repeated attempts to transmit it by grafting, juice inoculation and by insect vectors failed consistently. Later studies showed that the leaf-roll condition is due to genetic factors and that probably more than a pair of recessive genes are involved in its transmission.
Even after the genetic nature of the leaf-roll condition was definitely established, attempts were made to induce the leaf-roll condition in plants genetically normal by several methods : 1. Spraying their leaves with the juice from leaf-roll plants ; 2. Approach-grafting a leaf-roll scion onto a normal plant and vice-versa, following with defoliation, cutting back or shading of the normal graft component. This was done to stimulate translocation of the phloem contents from the leaf-roll scion or stock into the normal stock or scion respectively. It was thought that if leaf-roll were due to the genetically controlled production of a hormone-like substance, these treatments might induce the leaf-roll condition in plants genetically normal. The results, however, have been negative.
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LITERATURA CITADA
- 1. Bennett, C. W. and A. S. Costa. A curly top disease of tomato and tobacco in Brazil closely resembling curly top of sugar beet in the United States and Argentina. Jour. Agr. Research. (No prelo).
- 2. Costa, A. S. e R. Forster, Uma suspeita moléstia do vírus do fumo (Nicotiana tabacum L.) semelhante a "leaf-curl", presente no Estado de São Paulo. Jornal de Agronomia 2 : 295-302. 1939.
Datas de Publicação
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Publicação nesta coleção
08 Jun 2010 -
Data do Fascículo
1949
