The potential use of Arbuscular Mycorrhizal Fungi (AMF) to improve cocoa seedlings growth performance under environmental stress conditions

Environmental stresses provide the biggest challenges to cocoa sustainability. The potential benefit of arbuscular mycorrhizal fungi (AMF) to support the cocoa seedlings growth subjected to environmental stresses was evaluated. To do so, three months greenhouse study was conducted to examine the response of morphological performances, such as the quantity of leaves, stem diameter, plant height, and chlorophyll content. A glass box, with 100 x 60 x 80 cm³ dimension, equipped with an artificial heater was installed to modify the ambient microclimate provide different environmental conditions, i.e. inside and outside the glass box. Three levels of AMF dosages, i.e. 0, 5, and 10 g/pot, were evaluated. Data record suggest the higher stress condition of inside box environment, with air temperature of 35 - 40°C and relative humidity from 52 – 60%, than outside the box. The two-way analysis of variance revealed a negligible difference in the impact of AMF applications to number of leaves, and plant height. Yet, the stem diameter, with average value of ca. 6 mm, was significantly higher for cocoa seedlings growing outside the box implying the lower stress condition. Its improvement was observed inside the box with highest AMF dosage. However, the chlorophyll content was not significantly different among treatments, but with slight increase at the highest AMF level inside the box. This may suggest an improvement in terms of crop performance, subjected to environmental stress, resulting from AMF application.