The aim of this work was to evaluate the effect of 'Ponkan' mandarin (C. reticulata) x 'Pêra' sweet orange (C. sinensis) immature fruits storage and sucrose concentrations on embryos in vitro culture. Fruits with 3 to 4 cm in diameter were harvested and placed inside black polyethylene bags with lateral openings and stored at 5±1ºC during 135 days. Every 15 days a sample was removed, its embryos were excised and individually inoculated in test tubes containing 15 mL of MS medium (Murashige & Skoog, 1962) with sucrose (0, 1.5, 3, 6, 12, 18 and 24 g L-1) and 0.3 mg L-1 GA3 and 1 g L-1 activated charcoal. Those treatments rested 48 hours in the dark and later in a growth room at 27 ± 1ºC with a 16-h photoperiod and 32 µmol m-2 s-1 light intensity. Immature fruits can be stored for posterior excision and embryos culture. Fruits with 120 days after the pollination can be stored for at most 135 days without damaging the embryos viability. It was observed a better development of the aerial part and root system of plantlets from 'Ponkan' mandarin x 'Pêra' sweet orange embryos in MS medium with 12-18 g L-1 sucrose.
Embryo culture; nutrient medium; breeding
