Repetitive somatic embryogenesis from wild passion fruit (Passiflora cincinnata Mast.) anthers

Induction of somatic embryogenesis from in vitro-cultivated anthers represents a recent but poorly understood regeneration pathway for passion fruit species. Here, we aimed to develop an efficient system to produce and proliferate somatic embryos from cultivated anthers of Passiflora cincinnata . The floral buds were categorized into five different developmental stages (DS1 to DS5) according to their length and diameter. Their anthers were then cultured in induction medium at various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and 4.5 μM 6-benzyladenine. The control contained no plant growth regulators. Somatic embryogenesis started from the diploid sporophytic tissues of the anthers and continued indirectly through the formation of yellow and friable embryogenic calluses at 9.1 to 27.1 μM 2,4-D. Embryogenic calluses and primary and secondary embryos were significantly more numerous only when anthers at the DS2 stage were cultivated with 18.1 μM 2,4-D and 4.5 μM 6-benzyladenine. Secondary diploid somatic embryos formed on the surface of primary embryos via direct and repetitive embryogenesis, as well as directly from the hypocotyl of regenerated P . cincinnata emblings. The capacity to induce repetitive somatic embryogenesis represents a promising tool for Passiflora micropropagation. Key message Passion fruit anthers grown on auxin-rich medium have a high capacity for the formation and proliferation of diploid somatic embryos.