This study represents the first nationwide survey regarding the distribution of Cd content in cacao-growing soils in Colombia. The soil Cd distribution was analyzed using a cold/hotspots model. Moreover, both descriptive and predictive analytical tools were used to assess the key factors regulating the Cd concentration, considering Cd content and eight soil variables in the cacao systems. A critical discussion was performed in four main cacao-growing districts. Our results suggest that the performance of a model using all the variables will always be superior to the one using Zn alone. The analyzed variables featured an appropriate predictive performance, nonetheless, that performance has to be improved to develop a prediction method that might be used nationwide. Results from the fitted graphical models showed that the largest associations (as measured by the partial correlation coefficients) were those between Cd and Zn. Ca had the second-largest partial correlation with Cd and its predictive performance ranked second. Interestingly, it was found that there was a high variability in the factors correlated with Cd in cacao growing soils at a national level. Therefore, this study constitutes a baseline for the forthcoming studies in the country and should be reinforced with an analysis of cadmium content in cacao beans.

The in vitro establishment of Persea americana embryonic axes is critical for micropropagation and biotechnological applications, particularly following seed storage. This study aimed to evaluate the effects of seed storage duration and culture media composition on the in vitro development of P. americana (‘Toro Canyon’ and ‘Duke 7’ cultivars) embryonic axes in MS ( Murashige & Skoog 1962 ), MSm (30 % of macronutrient reduction) or SHm (modified from Schenk & Hildebrandt 1972 ) media. Morphological parameters, including embryo and embryonic axis length, width and mass, were recorded. The in vitro assessments included survival, rooting and rosette formation. The experiment followed a completely randomized design, with four replicates. The ‘Duke 7’ seeds were longer and heavier than the ‘Toro Canyon’ seeds, but did not produce significantly larger embryos. Without storage, ‘Duke 7’ exhibited a higher survival in SHm and lower rooting in MS, while ‘Toro Canyon’ showed no significant differences in survival or development among the media, except for lower rooting in SHm. Storage duration and packaging type did not significantly affect survival or rooting percentages, but influenced the rosette explant formation, which was lower in MS. After six months of storage, the ‘Duke 7’ embryonic axes maintained 93 % of viability, with 31 % forming rosettes and 69 % rooting. These findings suggest that the storage viability depends more on culture medium composition than seed biometry.