Date Palm Phoenix dactylifera L. Micropropagation

Date palm micropropagation began a quarter of a century ago (Reuveni, 1979; Reynolds & Murashige, 1979; Tisserat, 1979) and has progressed relatively slowly due to its inherent slow growth nature and limited research resources available to the developing countries where date palm is mostly grown. Several review articles describing early work on plant regeneration through indirect somatic embryogenesis and indirect adventitious organogenesis (Benbadis, 1992; Omar et al., 1992; Tisserat, 1984). Reports demonstrating the ability to regenerate date palm through direct regeneration, without callus stage, are also available (Sudhersan et al., 1993). Micropropagation through direct regeneration is thought to reduce the potential for undesirable somaclonal variants among regenerants while somatic embryogenesis mediated by callus stage is highly efficient and more popular in research laboratories (Al-Khayri, 2005).

In recent years, several studies have examined various components of the culture medium including sucrose (Veramendi & Navarro, 1996), silver nitrate (Al-Khayri & Al-Bahrany, 2001, 2004a), biotin and thiamine (Al-Khayri, 2001), auxins and salt strength (Al-Khayri, 2003), and other tissue culture factors (Bekheet et al., 2001). Cell suspension cultures have been employed to study aspects related to physiology (Al-Khayri, 2002; Al-Khayri & Al-Bahrany, 2004b), and somatic embryogenesis (Fki et al., 2003; Zouine et al., 2005). Expected to revolutionize date palm propagation, development of synthetic seeds is gaining research interest (Bekheet et al., 2002). In addition to offering an effective propagation means, tissue culture proved applicable in genetic improvement of date palm through induced mutations and in vitro selection (El Hadrami et al., 2005; Jain, 2005).

The micropropagation protocol described herein is based on indirect somatic embryogenesis using apical shoot tip explant for callus induction and subsequent plant regeneration.