Osmotic potential intensity in the control of direct somatic embryogenesis in coffee tree

Abstract The objective of this work was to characterize the effect of the osmotic potential of the culture medium on the control of direct somatic embryogenesis in coffee (Coffea arabica) tree. Leaf explants of the Mundo Novo cultivar and four hybrids were subjected to the direct route in the presence of polyethylene glycol 6000, at the following concentrations: 0, 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0%. Embryogenic structures and somatic embryos were formed at a threshold osmotic potential of up to -0.691 and -0.374 MPa, respectively, with a reduction or inhibition in these responses under a more negative osmotic potential.