MICROPROPAGATION OF WALNUT TREES (JUGLANS-REGIA L) AND RESPONSE TO ARBUSCULAR MYCORRHIZAL INOCULATION

Juglans regia clones were micropropagated through the establishment of in vitro shoot-tip cultures and induction of adventitious roots. Shoo t proliferation of juvenile J regia material was higher than with clon es established from adult trees. Genotype and juvenility of the plant material were determinant factors of the in vitro rooting ability. Roo ting of adult J regia clones was improved after rejuvenation by subseq uent subcultures. The sucrose concentration in the root elongation med ium affected the formation of secondary roots per rooted shoot and the acclimatization of plants. Mycorrhizal inoculation of micropropagated walnut trees improved post-acclimatization growth in greenhouse condi tions. Inoculation with the arbuscular mycorrhizal fungi Glomus mossea e or G intraradices significantly improved plant survival when transfe rred to nursery.