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Cacao (Theobroma cacao L.) is an important commercial crop and agricultural commodity worldwide; for some Latin American countries, it is an essential part of export products. In Colombia, this crop has promising conditions to extend and strengthen this agriculture sector. However, their productivity is low under current agricultural practices, mainly due to insufficient modernization and inadequate or no management of their nutritional schemes. This publication reviewed the different findings currently in the scientific literature regarding the factors that determine the nutritional status of cacao plants, such as the function and distribution of minerals, nutritional efficiency, soil properties, establishment systems, organic and organic and inorganic sources examined. Additionally, it highlighted the importance of using and expanding diagnostic tools to determine nutritional needs and the design of effective programs according to the particular conditions of each region and the genotypes planted. This conceptual journey highlights the existing theoretical and experimental gap in the identification of the factors that determine the nutritional status of the plantations and their effect on the implementation of the fertilization programs used today. Information together provides elements to adequately address this agronomic practice and the economic impact on farmers and the cacao production chain.

One major problem with cacao crops is the variability of plantings obtained from seeds. This has led to considering somatic embryogenesis (SE), a means of obtaining stable clones with minimal somaclonal variation; however, achieving this has not been possible with many genotypes. In this work, we used IMC67 genotype (rootstock in the traditional grafting process) to evaluated various SE protocols; four culture media for induction and expression primary embryogenesis (PSE): induction medium (INDI), expression medium (INDIEXP), primary callus induction medium (PCG), and secondary callus growth medium (SCG), as well as two explants (petal and staminode). Different culture times for PSE (15, 25, 35, 45, 55, 65 days) and SSE (10, 20, 30, 40, 50, 70, 80 days) were evaluated in terms of callus formation, PSE, and SSE. For acclimation, seven substrates were evaluated for plantlet survival. One hundred percent callogenesis was achieved at 50 days with the staminode in INDI, and the most PSE per explant (8) in INDIexp was achieved at 45 days. Secondary somatic embryogenesis (SSE) obtained the most globular and cotyledonary embryos (30) at 30 days in callus multiplication (CM2). The embryos achieved conversion and development into plantlets in maturation medium (MM6). Embryogenic efficiency from explants was 11.7 for PSE, and 15.2 for SSE. Acclimation obtained a 42.1% survival rate in the 70% sand- 30% soil substrate. This work reports a complete regeneration protocol via somatic embryogenesis up to plantlet development in a nursey for the IMC67 rootstock genotype; contributing to standardizing a high-quality plant production system.

In order to understand the causes of lack of regeneration in cacao somatic embryos, two cacao varieties with different responses to regeneration potential were described based on their capacity to store different compounds. It is well known that seed reserves play a central role in the regenerative capability of somatic embryos; thus, we followed histochemical changes and reserve fluctuations of proteins, polysaccharides and polyphenols during somatic embryogenesis (SE) in the two cacao varieties. The study showed that, in somatic embryos of the regenerating variety, polyphenols were localized mainly in the periphery of the embryo (epidermal cells) and proteins were the main storage substance in the embryo expression medium, while the non-regenerating variety had a high presence of polysaccharides with random distribution of polyphenols at the end of the embryo induction step.