Impact of Osmotica and Plant Growth Regulators on Somatic Embryogenesis of Date Palm

Abstract

An efficient somatic embryogenesis system is reported for date palm cv. Al-Fayda, a genotype resistant to the bayoud disease. Callus induction was achieved from adventitious bud explants cultured for 6 months on semi-solid Murashige and Skoog (MS) medium containing 4.5 μM 6-(dimethylallylamino) purine (2iP) and various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) or picloram. The highest somatic embryogenesis frequency (89%) was obtained on MS medium supplemented with 225 μM 2,4-D. Subsequently, embryogenic cultures were transferred to agitated liquid MS medium (maturation medium) containing various concentrations of mannitol, polyethylene glycol (PEG) or sorbitol. The highest rate of somatic embryo maturation (71.4 mature embryos per 100 mg callus) was achieved on the medium supplemented with 40 g l-1 PEG. Mature somatic embryos were then transferred to MS medium supplemented with gibberellic acid (GA3) or 1-naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BAP) at various concentrations. The highest frequency of germination and conversion (26%) was obtained on the medium containing 5 μM NAA and 5 μM BAP. The developed plants were then transferred to ex vitro conditions, where a survival rate of 77.02% was observed. The regeneration protocol established in the present investigation will be used for mass propagation of date palm cv. Al-Fayda.