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Analise genética da restauração da fertilidade em milho (Zea mays L.) com citoplasma macho-estéril do tipo C (Genetics of fertility restoration in maize (Zea mays l.) with male-sterile C-type cytoplasm)^*

Isabel Regina Prazeres de Souza^I; Luiz Sérgio Saraiva^II

^IEMBRAPA/Centro Nacional de Pesquisa de Agricultura Irrigada (CNPAI), Caixa Postal 341, 64200 Parnaiba, PI, Brasil
^IIDepartamento de Biologia Geral, Universidade Federal de Viçosa, 36570 Viçosa, MG, Brasil. Enviar correspondência para L.S.S.

ABSTRACT

The study was conducted at the Federal University of Viçosa, Minas Gerais, in 1986, to determine the genetics of fertility restoration in maize plants with male-sterile C-cytoplasm. The F₂ and first back-cross generations of male-fertile hybrids from crosses between inbred lines with normal cytoplasm and an inbred line with male-sterile C-cytoplasm were used. A Chi-square analysis of the number of male-fertile and partially fertile plants compared to the number of male-sterile plant progeny revealed the number of genes involved in fertility restoration. The data indicated the involvement of three independent genes (Rf₄/rf₄, Rfs/rfs, Rf₆Jrf₆). The mechanism of restoration depends on the dominant gene Rf₄ that is complementary to the dominant duplicate genes Rfs and/or Rf₆. So, even in the presence of male-sterile C-cytoplasm the plant will be fertile if the nuclear genotype has Rf₄ and at least one of the dominant genes Rfs or Rf6.

Keywords: genetics; fertility; maize; Zea mays; male-sterile; C-type; cytoplasm

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* Parte da Tese apresentada por I.R.P.S. à Universidade Federal de Viçosa, MG, como uma das exigências para obtenção do título de Magister Scientiae