In Vitro Morphogenesis of Direct Organs in Date Palm (Phoenix dactylifera L.) Siwy cv

Direct regeneration of organs offers a suitable approach for in vitro plantlets production evading the risk of genetic instability (mutations) associated with other regeneration routes involving callus phase. To stimulate adventitious bud formation, shoot tip explants of date palm Siwy cv. were cultured on MS medium containing 1 mg l-1 α-naphthaleneacetic acid (NAA) and 1 mg l-1 of 6-benzylaminopurine (BA), 6-furfurylaminopurine (Kin) and 2-isopentenyladenine (2iP) added individually or in combinations. The highest percentage of responsive explants (36.36%) was observed on a medium containing 1 mg l-1 NAA combined with 1 mg l-1 each of BA, Kin, and 2iP where 9.20 shoots per explant formed after 32 weeks of culture (i.e. the end of the fourth subculture). In contrast, the medium containing 1 mg l-1 NAA combined with 1 mg l-1 of only one cytokinin enhanced root formation but completely inhibited shoot development. Thus, the combinations of NAA, BA, Kin and 2iP at 1 mg l-1 each resulted in the highest regeneration percentage of shoots.