Micropropagation of olive (Olea europaea L.) and application of mycorrhiza to improve plantlet establishment

Micropropagation methods were developed for the three French varieties of olive (Olea europaea L.), Aglandau and Tanche, that have the Appelation d'Origine Controlee (AOC) status and one ecotype (05300, Laragne, France). Explants consisting of partially lignified nodal segments were collected from rejuvenated glasshouse-grown plant material. Nodal explants with axillary buds were cultured on different media. For AOC varieties, olive medium modified (OM mod) to contain half the concentration of macroelements was the most efficient in inducing bud break and growth when supplemented with 30 g l(-1) sucrose and 4 mg l(-1) zeatin. The resulting shoot buds were further multiplied and maintained on OM mod medium. Rooting was best achieved on OM supplemented with 4 mg l(-1) indole-3-butyric acid (IBA). For the Laragne ecotype, maximal shoot proliferation occurred when explants were cultured on woody plant medium supplemented with 15 g l(-1) sucrose and 0.1 mg l(-1) zeatin. Efficient rooting was achieved with 1 mg l(-1) IBA combined with 0.75 mg l(-1) naphthaleneacetic acid. After acclimatization in the glasshouse, survival rates ranged from 57 to 92%, depending on the genotype. Inoculation of Laragne ecotype microplantlets with the arbuscular mycorrhizal fungus Glomus mosseae significantly improved plant survival and subsequent plant development and growth.