Somatic embryogenesis from bud and leaf explants of date palm (Phoenix dactylifera L.) cv. Najda.

Abstract

An efficient regeneration system through somatic embryogenesis was developed for date palm cv. Najda. Adventitious bud and proximal leaf segments cultured on Murashige and Skoog (MS) medium supplemented with various combinations of auxins and cytokinins induced embryogenesis after at least 6months of culture. Somatic embryogenesis induction seemed correlated with the type of the explant, the induction period and the auxin used. The highest rate of somatic embryogenesis (86.0%) was obtained on bud explants cultured on MS medium supplemented with 45.0µM 2,4-dichlorophenoxyacetic acid (2,4-D), and 4.5µM kinetin or 4.5µM 6-(dimethylallylamino) purine (2iP). Whereas, low levels of embryogenesis were obtained on media supplemented with 1-naphthalene acetic acid (NAA) or 2-naphthoxyacetic acid (NOA). Proximal leaf segments showed somatic embryogenesis only when cultured on media supplemented with 2,4-D or picloram. Statistical analysis revealed significant effects of explant type and plant growth regulators (PGRs) combination on somatic embryogenesis. Somatic embryos were germinated successfully on PGR-free MS medium with or without activated charcoal (50.0-60.0 and 26.6-36.6%, respectively), and 80.0% of plantlets survived after transferring to a glasshouse for 6months. Our results will be useful for large-scale propagation of date palm cv. Najda, characterized by high fruit quality and bayoud disease resistance.