Early stages of somatic embryo genesis in plumule explants of Philippine Makapuno hybrid VMAC5

Abstract

Early bearing, self-pollinating and medium-to-big-seeded Philippine makapuno hybrid VMAC5 is propagated through in vitro embryo culture. This yields one plantlet per embryo in at least six months. To evaluate the potential of mass producing planting materials in vitro, a protocol developed by the Philippine Coconut Authority was used to initiate somatic embryogenesis in whole and cut plumule explants from VMAC5 nuts. Calloid initiation was obtained 8 to 12 days from initial culture in semi-solid medium under dark incubation at 8% in cut and 5% in whole plumules. White translucent structures characteristic of embryogenic calloids formed on the cut plumules one month after initial culture. At 60 days old, distinct ear-shaped pre-embryogenic structures and white shiny globular pre-somatic embryos developed in whole explants. Hard, friable, and whitish to yellowish calloids with pre-embryogenic masses were also observed in cut plumule explants. At 90 days after the initial culture, more distinct pre-somatic and globular somatic embryos developed in both explants.