The use of zygotic embryos as explants for in vitro propagation: an overview

Plant propagation in vitro via somatic embryogenesis or organogenesis is a complicated process requiring the proper execution of several steps, which are affected by culture conditions and environment. A key element for a successful outcome is the choice of the explants. Several studies have shown that factors such as age, ontogenic and physiological conditions, and degree of differentiation affect the response of the explants to culture conditions. As a general rule, younger tissues, such as zygotic embryos, are the preferred choice for tissue culturists as they have better potential and competence to produce embryos and organs compared to more differentiated and mature tissues. This chapter focuses on how competence and commitment to regenerate embryos and organs in cultures are acquired by somatic cells and why zygotic embryos are so often utilized for propagation practices.