Somatic embryogenesis from leaf- and petiole-derived callus of Vitis rupestris

Somatic embryogenesis from leaf- and petiole-derived calli of Vitis rupestris was obtained with an efficiency of 3.2% and 4.2% of plated explants, respectively on two combinations of 6-benzyladenine and 2,4-dichlorophenoxyacetic acid (1/0.1 and 1/1 mgl(-1)) added to MS medium. Embryogenic callus, embryo subcultures and somatic embryogenesis from somatic embryos were obtained either in the presence of 1 mgl(-1) indole-3-acetic acid or 0.1 mgl(-1) indole-3-butyric acid added to MS or NN media. Within a 4-month culture, embryo germination occurred at a frequency of 13% of explanted embryos when chilling at 4°C was provided for two weeks and a combination of 6-benzyladenine (1 mgl(-1)) with indole-3-butyric acid (0.1 mgl(-1)) was added to NN medium supplemented with casein hydrolysate (250 mgl(-1)). A higher frequency (51%) was obtained in a longer culture time (9 months) when only indole-3-butyric acid was present in the medium and in absence of chilling.