Genética de coffea V— Hereditariedade da coloração bronzeada das folhas novas de coffea arabica L.
Data
1942-06
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Instituto Agronômico (IAC)
Resumo
No presente artigo os autores apresentam os resultados da análise genética referentes à hereditariedade das cores verde, bronze claro e bronze escuro das folhas novas de Coffea arabica L. Baseados em extensos dados de autofecundação, hibridação (F1 e F2) e back-crosses conclue-se que apenas um par de fatores alelomorfos Br-br é responsável pelo aparecimento daquelas cores, br br constituindo o tipo verde, Br br o bronze claro e Br Br o bronze escuro; a coloração bronze escuro é, pois, incompletamente dominante sobre o verde, o Fi entre estes tipos se apresentando de uma tonalidade bronze-clara. No grupo dos bronze-escuros (homozigotos) existe certa variabilidade na expressão máxima da coloração o que, em parte, é atribuido à presença de fatores genéticos modificadores, que intensificam ou diluem esta coloração. À luz dos resultados obtidos, discutem-se os trabalhos de Stoffels (8) e Narasimha Swamy (7) que versam sobre o mesmo assunto.
In the present paper the authors are publishing the results of the genetical analysis of three color types occurring in young leaves of Coffea arabica L : green ; dark bronze and light bronze. Based on extensive data obtained from progenies, Fi and F2 hybrids and back-crosses, it is concluded that only one pair of allelomorphic genes control these colors for which the symbols Br-br are proposed : br br, the double recessive, constitutes the green type, Br br, the heterozygote, the light bronze one and Br Br, the double dominant, the dark bronze one. The dark bronze colour is therefore incompletely dominant over green, the Fi between the two being light bronze. In the group of homozygote dark bronze plants a certain variability of the maximum intensity of the bronze colour is noticed, which is most probably due to modifyers which intensify or dilute the expression of this character. Two papers, respectively by Stoffels (8) and Narasimha Swamy (7) dealing with the same subject are critically discussed.
In the present paper the authors are publishing the results of the genetical analysis of three color types occurring in young leaves of Coffea arabica L : green ; dark bronze and light bronze. Based on extensive data obtained from progenies, Fi and F2 hybrids and back-crosses, it is concluded that only one pair of allelomorphic genes control these colors for which the symbols Br-br are proposed : br br, the double recessive, constitutes the green type, Br br, the heterozygote, the light bronze one and Br Br, the double dominant, the dark bronze one. The dark bronze colour is therefore incompletely dominant over green, the Fi between the two being light bronze. In the group of homozygote dark bronze plants a certain variability of the maximum intensity of the bronze colour is noticed, which is most probably due to modifyers which intensify or dilute the expression of this character. Two papers, respectively by Stoffels (8) and Narasimha Swamy (7) dealing with the same subject are critically discussed.
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KRUG, C. A.; CARVALHO, A. Genética de coffea V - Hereditariedade da coloração bronzeada das folhas novas de coffea arabica L. Bragantia, Campinas, v. 2, n. 6, p. 199-220, 1942.