SHOOT REGENERATION FROM ADVENTITIOUS BUDS INDUCED ON JUVENILE AND ADULT ALMOND (PRUNUS-DULCIS MILL) EXPLANTS

Adventitious shoot regeneration was achieved from almond leaves, cv. B oa Casta excised from in vitro cultures of juvenile and adult material . Murashige and Skoog (1962) medium (MS) was found to be more efficien t for adventitious shoot induction than a modified medium of Quoirin e t al. (1977) when using identical growth regulator supplements. Thidia zuron (TDZ) at 4.54, 5.90, 6.81, and 9.08 mu M was used in all inducti on media, together with indole-3-butyric acid (IBA), indole-3-acetic a cid (IAA), or a combination of IAA and 2,4-dichlorophenoxyacetic acid (2,4-D). When N-6-benzyladenine (BA) was used instead of TDZ, no adven titious shoots were induced. Leaf explants of juvenile origin yielded the highest regeneration rates (40.0 and 38.2%) and required higher co ncentrations of TDZ for shoot induction than leaves of adult origin. A n increase from 15.0 to 35.3% in the regeneration ability of adult lea f explants, tested on one of the induction media [modified medium of Q uoirin et al. (1977) supplemented with 5.90 mu M TDZ and 2.85 mu M IAA ], was achieved when donor shoots were subcultured twice on a medium w ith a low BA concentration of 1.33 mu M.