Somatic Embryogenesis in Theobroma cacao L.

Abstract

Theobroma cacao L. is a tropical tree originating in the Amazon, where it grows naturally in the shade of tropical rainforests. Cacao sub-products, such as butter and powder, are produced as principal components of chocolate and contain important nutritional compounds such as polyphenols and flavonoids. However, bean production is decreasing because plantations are antiquated and unproductive. Cacao propagation has been traditionally performed through classical propagation methods, such as grafting or rooted cuttings, but those methods are not sufficient to obtain large quantities of planting material with the desired genetic quality and optimal plant health. In the search for solutions to this problem, somatic embryogenesis (SE) is a vegetative method used for cacao propagation that has the potential to be explored. SE is a type of clonal propagation by which totipotent cells in the somatic tissue can develop into embryos and subsequently convert into plants.This method offers significant technological advantages because it is possible to obtain a large quantity of disease-free planting material with good agronomic characteristics and genetic stability. In T. cacao, tow techniques of in vitro micropropagation have been reported as direct and indirect SE. Indirect SE requires the additional step of cell dedifferentiation, unlike direct SE, which does not require this step. Here, we report a protocol using direct and indirect SE techniques using two types of culture methodologies-solid and liquid culture media.