IMPACT OF SOME CLIMATIC AND PHENOLOGICAL PARAMETERS ON THE CALLOGENESIS AND SOMATIC EMBRYOGENESIS VARIATIONS IN COCOA

Callogenesis and somatic embryogenesis (SE) are influenced by several factors including climate and phenology. To assess such an influence, the percentage of callogenesis and SE variations depending on five climatic and two phenological parameters was measured for 2 years. Staminodes and petals from six hybrids and two clones as controls were cultured in bulk, onto three distinct calli induction media only differing in hormonal concentrations. From the results, it emerged that sole leaves flush does not vary from year to year. Maximal temperature and flowering level are the most stably linked. Non-linear regression provides the best R2-values of fitted curves. This shows that the link among climate, phenology, callogenesis and SE is not linear. In the first year, in control clones, climatic and phenological parameters explain 52.80% callogenesis variations, against 31.50% for SE. Therefore, climate and phenology significantly influence callogenesis, but not SE. For further industrial production of secondary metabolites such as butter, theobromin and chocolate aroma from calli, it would be desirable also to identify the favourable periods for calli production. Nevertheless, somatic embryos will continue to be produced all the year irrespective of period.