Plants regeneration from ovule culture of Citrus reticulata Blanco cv. Dancy

Abstract

Undeveloped ovules of Citrus reticulata Blanco cv. Dancy were cultivated with the objective to determinate the effect of pollination, harvesting time and culture conditions appropiated for induction of embryogenesis and embryo production. It was verified the effect of in vivo grafting of cotiledonary embryos, in ten-month-old rootstock obtained from seeds, on the rapidity of obtention of disease-free plants and on the reduction of the juvenility stage. Ovule originated from pollinated and non-pollinated flowers collected 7, 14, 21 and 28 days after anthesis grown under light and dark conditions were cultured in basic medium MT, added with 500 mg.L^-1 of malt extract. Cotiledonary embryos, 4-6 mm long, obtained in vitro were grafted in vivo on rootstocks. Embryos were directly obtained from ovule culture, however it was observed the formation of a high number of abnormal embryos in all treatments. Whole plants were developed on the same basic medium. It was not observed the formation of callus until 120 days. Differences related to the percentage of ovules that induced embryos and the number of embryos were observed in all treatments. The success rate of embryo grafting was 23%, however, it was observed a fast seedling development, which is a promissing technique for breeding programs and maybe in the mass propagation of virus-free plants, in case the juvenile phase be reduced.