Palms are a much neglected plant group in terms of understanding their development and vegetative propagation potential. Yet, they are economically important in tropical and subtropical regions. The rapid propagation of date palm as well as propagation from a mature specimen, is impossible due to the limited number of offshoots produced and the fact that offshoot production is limited to a certain period in the palm’s life span. As mentioned above, seed propagation of date clones and cultivars is impractical.
The application of tissue culture techniques for date palm, also called in vitro propagation, has many advantages (in comparison to the above two techniques) and enables the following:
– Propagation of healthy selected female cultivars (disease and pest-free), Bayoud resistant cultivars, or males having superior pollen with useful metaxenia characteristics which can easily and rapidly be propagated;
– Large scale multiplication;
– No seasonal effect on plants because they can be multiplied under controlled conditions in the laboratory throughout the year;
– Production of genetically uniform plants;
– Clones to be propagated from elite cultivars already in existence, or from the F1 hybrids of previous selections, and seed-only originated palms;
– Ensure an easy and fast exchange of plant material between different regions of a country or between countries without any risk of the spread of diseases and pests; and
– Economically reliable when large production is required.
The success of propagating monocotyledons in vitro has been limited to relatively few herbaceous species. Similarly, most dicotyledons, successfully tissue cultured, have also been the herbaceous types. It has been postulated that in woody plants, the ability to regenerate plantlets using tissue culture techniques was lower in comparison to herbaceous plants. In palms, until twenty years ago, little success was achieved in inducing and maintaining good callus. Plant tissue culture techniques have been employed to clone a wide range of plants and economically important palms e.g., coconut, oil and date palms (Cheikh et al., 1989).
In reviewing date palm tissue culture, the classification followed will be that of behaviour and relevant techniques of tissue culture as a whole from a perspective of their eventual applications to date palm (Zaid and Djerbi, 1984; Zaid, 1985; 1986a; 1986b).