IntroductionSomatic embryogenesis is the process by which somatic cells, under induction conditions, generate embryogenic cells that go through a series of morphological and biochemical changes that result in the formation of somatic embryos (Quiroz-Figueroa et al., 2006). This process is feasible because plants possess cellular totipotency, by which individual somatic cells can regenerate a whole plant (Vasil and Vasil, 1972). The acquisition of embryogenic competence by somatic cells is a complex process that comprises several phases: dedifferentiation, cell reactivation, cell divisions, and various metabolic and developmental reprogramming steps (Ochatt, 2010). The technique of embryogenesis makes an attractive tool not only for mass production but also for crop improvement and genetic transformation (Pérez-Clemente et al., 2004;Quiroz-Figueroa et al., 2006;Namasivayam, 2007). However, the initiation of somatic embryogenesis in plants depends on both extrinsic and intrinsic factors.Among the various extrinsic factors that may induce an embryogenic pathway of development, plant growth regulators, especially auxins, have been known to be implicated in cell cycle regulation, cell division, and differentiation (Del Pozo and Manzano, 2014) as well as in the induction of somatic embryogenesis (Pasternak, 2002). Picloram (4-amino-3,5,6-trichloropicolonic acid), a synthetic auxin, is particularly effective for induction of cell division, proliferation, and further regeneration such as somatic embryogenesis in a range of plant species (Barro et al., 1999;Sanchez-Romero, 2005;Gomes et al., 2006). It acts by inducing auxin sensitivity in nondividing cells that are arrested in G1 (growth phase), enabling them to reenter the S phase (DNA replication) and mitosis (He et al., 2010).Regarding intrinsic factors, genotype is the most determinant in embryogenic competence (Fehér, 2008;Ochatt et al., 2010;Isah, 2016). Various groups, families, and genera are still regarded as recalcitrant to embryogenesis, like Prunus (Druart, 1999). Such recalcitrance has handicapped and delayed the exploitation of biotechnology approaches for breeding in many species and was and still is the subject of research in many laboratories (Ochatt et al., 2010).