The browning of plant tissue and organs is a major constraint in tissue culture of cocoa (Theobroma cacao L.). This study aims to evaluate callogenic and embryogenic potentialities of three genotypes cocoa on culture media supplemented with different types and concentrations of antioxidants. Polyvinylpyrrolidone (PVP), ascorbic acid, silver nitrate and cysteine were used as antioxidant agents. The explants staminode and petal were excised from immature buds of the flowers of genotypes cocoa C1, C8 and C14. The results showed that the induction rate of callus derived from the petal and the staminode varied with the genotypes tested. Except 21 mg/l of silver nitrate, the others antioxidants used namely ascorbic acid, PVP and cysteine have enhanced the callus induction of the genotype C8. In comparison with the control, the callus browning of the three genotypes was reduced two to three times when the culture media were supplemented with various concentrations of the silver nitrate. After 72 days of culture, somatic embryos were induced on callus derived from the petal explants with all the studied genotypes. Addition of PVP (300 mg/l) in the induction medium improved the rate of somatic embryos of the genotypes C1 and C14. The improvement of responses to somatic embryogenesis in reducing the rate of browning of cultures will allow a mass production of the high-yield cocoa genotypes.

Objective: In cocoa tree (Theobroma cacao L.), some elite genotypes have shown, in standard study conditions, an absence or a very weak response to induction of somatic embryos. This is the case of the original C8 genotype Trinidad. This study aims to improve the production of somatic embryos in this genotype Methodology and results: To do this, staminodes and petals excised from immature buds of genotypes C1, C8 and C14 were used. Genotypes C1 and C14 are embryogenic under standard conditions. These floral explants were cultured on induction media differing by the type and concentration of auxins. Callus induction obtained in the three studied genotypes ranged from 80% to 90% with the petal explants and from 70% to 80% with the staminodes regardless of the type and concentration of auxins. Transfer of callogenic explants to DKW (Driver & Kuniyuki, 1984) medium supplemented with sucrose and glucose allowed the induction of somatic embryos at mean rates varying from 5% to 20% after only 84 days with petal explants and media supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) and 2, 4, 5-trichlorophenoxyacetic acid (2,4,5-T). No induction of somatic embryos was observed on the control medium with the C1, C8 and C14 genotypes. The C1 genotype induced somatic embryos in the presence of all concentrations of auxins. The highest rate of embryogenic callus and somatic embryo induction was obtained with 18 μM of 2, 4, 5-T in all C1 genotypes (39.29 ± 0.28; 17.98 ± 0.10), C8 (36.29% ± 0.26 and 15.01 ± 0.07) and C14 (33.92% ± 0.26 and 14.50 ± 0.16). The 2, 4, 5-trichlorophenoxyacetic acid (2, 4, 5-T). at 18 μM is the most appropriate auxin to remove recalcitrance in cocoa genotype C8. The use of higher 18 μM concentrations of 2, 4, 5-trichlorophenoxyacetic acid (2, 4, 5-T). and its application to other recalcitrant genotypes could confirm its beneficial effect on the removal of recalcitrance to somatic embryogenesis in cocoa. Conclusion and application of results: 18 μM concentration of 2, 4, 5-trichlorophenoxyacetic acid (2, 4, 5-T) gave the best percentage of embryogenic explants and the highest average number of embryos in the three genotypes tested. Therefore, this protocol using 18 μM of 2, 4, 5-trichlorophenoxyacetic acid (2, 4, 5-T) could be used to overcome recalcitrance to somatic embryogenesis in cocoa.

Climate change, coupled with insufficient and irregular rains, led to a decline in the productivity of Ivorian cocoa production. The present study aimed to screen three cocoa (Theobroma cacao L.) genotypes in order to evaluate their response to water stress at callus and somatic embryos induction and proliferation stages. Staminode and petal explants of the genotypes C1, C14 and C16 from the collection of National Center of Agronomic Research (CNRA) of Ivory Coast, were placed on medium DKW (Driver & Kuniyuki Walnut) in the presence of different concentrations of Polyethylene glycol (PEG) 6000 (0, 25, 50, 75, 100 and 125 g/l). This polymer was used as osmoticum to stimulate water stress. Data were recorded for callus induction frequency, callus fresh weight, embryogenic callus percentage and average number of somatic embryos. The results obtained showed that intensity of callus proliferation decreased with increasing concentration of PEG 6000. In all genotypes tested, only the petal explants underwent somatic embryogenesis. The induction rates and average number of somatic embryos per explant were reduced with the increase in the concentration of PEG 6000. Among the tested genotypes, C1 produced somatic embryos with all concentrations of PEG 6000 and expressed highest frequencies of induction (62%) and average number of somatic embryos per explant (6.22). This genotype would be the most tolerant to water stress. Somatic embryos obtained with high concentrations of PEG 6000 in this study provide an important basis for the selection and further production of water stress-tolerant varieties of cocoa.

The current state of cassava production and technology level as well as commercialization and consumption aspects were studied in Côte d’Ivoire. The study involved a sample of 570 actors of the value chain randomly selected in three (3) agro ecological regions (south, west and centre). Using a baseline survey questionnaire, 150 producers, 195 transformers and 195 consumers were interviewed. Results showed that farmers and consumers households are in majority led by men (80 and 61%) while transformers households are led by women (81%). Concerning the level of adoption of cassava technologies, it was found that about 35% of cassava growers are aware about the new cassava varieties and more than 80% agreed to use them. The analysis performed in agro ecological regions revealed that traditional varieties are preferred (40 % to 90 %) to improved varieties. Improved varieties, Bocou 1 (10.67%), TMS4 (2)1425 (0.67%) and Bocou 2 (0.67%) are less preferred for cultivation in spite of high yields, food processing or taste qualities, respectively mentioned by farmers. More than 50 % of farmers agreed to adopt the Rapid Seed Multiplication technique. Contrary to the localities of Man (West) and Bonoua (South) where pounded cassava is more consumed (89.29% and 66%), dehydrated cassava (Attieke) food is the most consumed in other localities surveyed. In spite of the high yield of improved varieties and the desire of cassava growers to adopt new cassava technologies, research and extension services should be reinforced taking into account agro ecological specificities of production, commercialization and consumption.

This work was carried out in collaboration between all authors. Author Kouassi Konan Marius designed the study, performed the statistical analysis, wrote the protocol and wrote the first draft of the manuscript.