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The detailed description of growth stages of useful plants followed by adequate codification facilitates communication between scientists and practicians if, for example, new findings of science have to be transferred to management procedures or if experiences made at one growing site have to be adapted to another. We describe the growth stages of the worldwide species of cacao trees (Theobroma sp.) to prepare the basis for production management, comparisons of epidemiological studies of disease, of growth patterns under different environmental factors and of genetically clone specific parameters. The codification follows the ‘extended BBCH (BBCH, Biologische Bundesantalt, Bundessortenamt and CHemische Industrie, Germany) scale’, a numerical system that differentiates between principal, secondary and tertiary growth stages. Each growth stage presented from seed germination to crown development and harvest is correlated with general management practices. This scale will be of great help to cacao growers and scientists around the world for better communication, more efficient planning of management practices and experiments.

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The present study aimed at developing temporary immersion bioreactor techniques for multiplication of cacao somatic embryos. Temporary Immersion System (TIS), i.e. flooding of plant tissue at regular time intervals provides an efficient way to propagate plants. Somatic embryos were regenerated in twin flask bioreactors. The TIS proved to be suitable for mass regeneration of somatic embryos and for their subsequent direct sowing. The number of embryos after 3 months of culture was significantly higher in TIS cultures than in the solid medium variant. TIS also improved embryo development regarding the conversion to torpedo shaped forms. Matured embryos derived from TIS and pre-treated with 6% sucrose were converted into plants after direct sowing. Additionally to the influence of culture conditions on the development of somatic embryogenesis the content and composition of free amino acids were analysed. The content of free amino acids in somatic embryos rose as immersion frequency increased. The endogenous free GABA content in embryogenic callus was significantly higher than in non-embryogenic callus.

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The cocoa relatives T grandiflorum (cupuaçu) and T bicolor (macambo) are promising crop plants for sustainable agroforestry in the Amazon region of South America. The market for cupuaçu is expanding since the fruit flesh is utilised by the foodstuffs industry. Attempts to commercialise chocolatelike wares from the seeds have failed so far because of unreliable product quality. It is not known whether this is due to an insufficient aroma potential of cupuaçu seeds. We therefore investigated the proteolytic enzymes and the seed storage globulins which are both decisive for the formation of aroma precursors in cocoa. We found that the activities of the aspartic endopeptidase and the carboxypeptidase in T bicolor and T grandiflorum differed slightly from those in cocoa. The specificity of the carboxypeptidase for hydrophobic amino acids was quite similar across the three species, while the optimal pH of the T grandiflorum enzyme was lower than that of the other species. The qualitative and quantitative differences between the globulins indicate a lower maximum yield of aroma precursors in T grandiflorum and a higher maximum yield of aroma precursors in T bicolor, compared to cocoa. We conclude that the quality of chocolate-like products made from the studied cocoa relatives can be improved by adapting fermentation procedures to particular biochemical features of these seeds.

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