Somatic embryogenesis through in vitro anther culture of Citrus sinensis L. Osbeck 'Moro'

In many crops, anther culture is the most used method to induce gametic embryogenesis, aimed to regenerate homozygous plants. However, also somatic embryogenesis can be obtained by this method, when somatic tissue is involved in the regeneration process. Many factors can affect this procedure, such as genotype, temperature pre-treatment applied to floral buds, pollen developmental stage, donor plant state, culture media composition and culture conditions. Anthers of Citrus sinensis L. Osbeck 'Moro', were collected at the vacuolate stage, and after a chilling (4 degrees C) pre-treatment of 7 days, were placed on the same medium, evaluating different temperature stresses applied after placing them in culture. In this study, the effect of three thermal treatments, compared with direct in vitro culture of the anthers (after the pre-treatment of the floral buds at 4 degrees C for 7 days), was observed in cultivar 'Moro'. Embryo regeneration has been obtained and their characterization, through ploidy and molecular analyses, showed that they were heterozygous tetraploids.