Evaluation of the Inoculation Effect of Arbuscular Mycorrhizal Fungi on the Growth of Cocoa Seedlings (Theobroma cacao L.) in the Nursery

Abstract

Cocoa farmers face many problems related to the acquisition of quality planting material for their farms to guarantee a good annual yield of cocoa beans. This is justified by the multiple constraints to which the cocoa tree is subjected to from the nursery. Faced with this, research is based on the diversification of production systems to reverse this trend. One of the promising methods is the promotion of the use of mycelial microorganisms such as Mycorrhizae to obtain vigorous plants resistant to various pathogens in the nursery. To achieve these objectives, the microbiological characterization of the different substrates used by nurserymen and the impact of fertilizers on the development parameters of young cocoa plants of the Tafo 79/501 variety were evaluated in the nursery. The results obtained indicate that the substrates used by nurserymen contain the AMF spores. However, the germination of these spores and the survival of mycorrhizal structures are compromised by the regular use of pesticides. Also, the height of the stem, the diameter at the collar of the stem, the fresh and dry biomass, the chlorophyll rate as well as the rate of root colonization of AMF are higher in cocoa plants whose substrate has been inoculated with AMF compared to other pots. Overall, biofertilizers are conducive to the harmonious development of cocoa seedlings in the nursery, which guarantees good productivity.