Coadjutants of somatic embryogenesis, such as malt extract and glycerol, induced formation of 50 % of the embryogenic structures in calluses of Citrus sinensis cv. Jaffa after 6 weeks of in vitro culture. The calluses of different cultivars were obtained from nucellar tissue in a Murashige and Skoog (1962) culture medium (MS), with 1.0 mg×liter-1 dichlorophenoxyacetic acid (2,4-D) and 1 mg×liter-1 kinetin. Adding coadjutants and reducing sources of both ammonium and nitrates in the medium were also tested in in vitro culture of calluses of different cultivars of Citrus. Combining treatments of L-proline and L-glutamine, the subcultured calluses of Citrus cv. Valencia Late had the best embryogenic response to the treatments with 150 mg×liter-1 L-proline, with the source of ammonium reduced to 75 %, and the Murashige and Skoog salts diluted to 50 %. The treatments with MS salts and ammonium in the different treatments with L-glutamine promoted the formation of globular, or embryogenic, structures in the calluses of C. sinensis L. Osbeck cv. Parson Brown C. sinensis L. Osbeck cv. Jaffa, and, C. sinensis L. Osbeck cv. Valencia Late. In cell suspension culture, the calluses taken from the cultivar C. sinensis x C. reticulata cv. Monica, developed embryogenic structures after eight weeks, and later, green embryos in liquid mediums to which 46 g×liter-1 of galactose and 38 ml×liter-1 of glycerol plus 500 mg×liter-1 of malt extract were added. There was no response in cell cultures with mediums in which abscisic acid and L-proline were used.

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