ISSN: 1659-2751



Effect of Arbuscular Mycorrhizal Fungi on the Development of Cocoa in the Greenhouse


Arbuscular mycorrhizal fungi (AMF) contribute to the mineral nutrition of plants, especially for those nutrients that are not mobile in the soil, as in the case of P. The nutrients that are extracted by the external mycelium of the fungus from impenetrable microsites are absorbed by the root hairs. This research studied the cross inoculation of different clones of Theobroma cacao with inoculated cacao clones to determine if specificity exists between the AMF of those clones, as well as to quantify the effect on the growth of T. cacao in greenhouse conditions. The experiment was conducted with a random factorial design of 3 x 4 (host x inoculum) using 12 treatments and four repetitions. The structure of the factorial arrangement consisted of cross inoculation of AMF colonized roots from three clones of T. cacao (CC-246, IMC-67 and EET-184). The inoculation of the T. cacao plants with AMF was successful. All inoculated plants showed colonization by AMF with an average of 42.0 %. The relative dependence of the T. cacao plants on AMF varied by clone for each plant inoculated with a resulting range of between 4.85 % and 46.0 %. Plants inoculated with AMF had a greater diameter, higher biomass, and root biomass and total biomass production. All clones inoculated with AMF fixed more C than the control treatment and absorbed a higher concentration of N, P, K, Mg, Cu, and Zn. There was no particular specificity of the inoculated clones. Rather, the inoculation itself was important. The carbon fixation and nutrient absorption by the clones inoculated with AMF was reflected in an increased biomass, root biomass and total biomass production, which demonstrated that the practice of inoculating T. cacao plants in the greenhouse is a practice that would produce better plants to be taken to the field.

Key words: absorption of nutrients, cocoa, arbuscular mycorrhizal fungi, inoculation.

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