This work had as objective to produce citrus somatic hybrids between sweet oranges and pummelos. After chemical fusion of sweet orange embryogenic protoplasts with pummelo mesophyll-derived protoplasts, plants were regenerated by somatic embryogenesis and acclimatized in a greenhouse. The hybrids of 'Hamlin' sweet orange + 'Indian Red' pummelo and 'Hamlin' sweet orange + 'Singapura' pummelo were confirmed by leaf morphology, chromosome counting and molecular analysis. These hybrids have potential to be used directly as rootstocks aiming blight, citrus tristeza virus, and Phytophthora-induced disease tolerance, as well as for rootstocks improvement programs.

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Thiago dos Santos Silveira, pelo apoio, convívio e solidariedade. Aos funcionários David Ulrich, Aparecido Donizete Serrano, José Antônio Volpato e Éder de Araújo Cintra, por todo trabalho dispensado. Ao Departamento de Fitopatologia, pela análise do solo. A Alexandra Pavan, em especial, pela cumplicidade e companheirismo.