EFFECT OF TECHNIQUE AND DARKNESS ON THE SUCCESS OF MERISTEM MICROGRAFTING OF PICEA-ABIES

The possibility of micrografting in vitro shoot meristems of Picea abi es were investigated on a 18 year-old Norway spruce clone. The rates o f success were shown to be greatly influenced by the grafting techniqu e used and by light, with a positive effect of a 2 to 3 week darkness period applied to the stocks just after they had been grafted. Average scores of more than 50 % of success were obtained. However, substanti al variability in terms of shoot expansion among the grafted plants ex isted in vitro, as well as after transfer to ex-vitro conditions.