MICROPROPAGATION OF OLIVE (OLEA-EUROPAEA L), CLONE OBLONGA, BY IN-VITRO EMBRYO CULTURE

A method for micropropagating olive, Olea europaea L., clone Oblonga f rom embryos is reported. This clone makes a good autogamous rootstock, tolerant to nondefoliating races of Verticilium dahliae. Pits removed from mature fruits were scarified in 2% H2SO4 for 48 h; embryos were removed and implanted in Olive medium (OM) + 30 g/l sucrose + 6 g/l ag ar, pH 5.7. Growth regulators were tested in several combinations: OM alone, OM + 0.8 mg/l benzylaminopurine (BAP) and 0.01 mg/l naphtalenea cetic acid (NAA); OM + 4 or 10 mg/l hydroximethylbutenyl aminopurine ( isomer mixture zeatin-ZEA), or 5 or 10 mg/l 2 isopentenyladenine (21P) and 5 and 10 mg/l BAP. Embryos regenerated plants in all combinations , though the most vigorous shoots and most rapid development was obtai ned after 20 to 25 days in OM + 4 mg/l ZEA. Shoots were sectioned into single-node cuttings and subcultured in the same media. After 30 days in OM plus either 4 mg/l ZEA or 5 mg/l 2iP or 5 mg/l BAP shoots reach ed 3-4 cm long and produced an average of 4-6 nodes (micropropagation rate 1:5), regenerating 3125 plants from a single embryo in 5 months ( 5 cycles). ZEA may be replaced with other less expensive synthetic gro wth regulators. Sixty to 70% of the shoots rooted in OM + 3 mg/l indol ebutyric acid or 2 mg/l NAA. The period from embryo establishment to t ransfer of the regenerated plants to the soil was 5 months. Acclimatio n was completed in 90 days, by successive transfers to less controlled conditions. Seventy percent of the regenerated plants survived this s tage.