Author(s)

Manlé Tokpapon Eliane^1,2*, Kouassi Kan Modeste³, Soumahoro Brahima André⁴, Koffi Kouablan Edmond¹, Koné Mongomaké²

¹Laboratoire Central de Biotechnologie (LCB), Centre National de Recherche Agronomique (CNRA), Abidjan, Côte d’Ivoire.
²Laboratoire de Biologie et Amélioration des Productions Végétales, UFR Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d’Ivoire.
³Laboratoire de Physiologie Végétale, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire.
⁴Section SVT, Département des Sciences et Technologies, Ecole Normale Supérieure d’Abidjan, Abidjan, Côte d’Ivoire.

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.

Water Stress, Cocoa, PEG 6000, Somatic Embryogenesis, Selection

Eliane, M. , Modeste, K. , André, S. , Edmond, K. and Mongomaké, K. (2019) Effect of Water Stress Induced by Polyethylene Glycol 6000 on Somatic Embryogenesis in Cocoa (Theobroma cacao L.). Agricultural Sciences, 10, 1240-1254. doi: 10.4236/as.2019.109092.