Impact of Rhizophagus irregularis and Trichoderma sp. Inoculation on Cassava (Manihot esculenta Crantz) Agronomic Parameters

Abstract

Background: In Côte d’Ivoire, cassava (Manihot esculenta Crantz) is cultivated throughout the country and represents an important source of income and food security. However, its production commonly involves chemical inputs that may contribute to declining soil fertility. Aims: This study evaluated the effects of Rhizophagus irregularis and Trichoderma sp. on cassava growth and yield. Place and Duration of Study: The study was conducted in two stages: a two-month in vivo cultivation phase at the Ecology Research Centre in Abidjan, southern Côte d’Ivoire, followed by a 10-month field phase in Azaguié, south-eastern Côte d’Ivoire. Methodology: The Yacé and TMS30572 cultivars were grown in vivo and under field conditions and inoculated at planting with R. irregularis (RI) and Trichoderma sp. (TRI). The fungi were applied separately and in combination (RI + TRI). Under field conditions, NPK (10-18-18) fertiliser served as the positive control for yield evaluation. Results: After two months, stem diameter, plant height, number of leaves, and leaf area were enhanced by RI and RI + TRI, whereas the effect of TRI varied with the plant organ and cultivar. For each cultivar, mycorrhizal colonisation intensity and frequency did not differ significantly between the RI and RI + TRI treatments, confirming the mycotrophic response of cassava. The RI, NPK, and RI + TRI treatments produced statistically comparable yields within each cultivar. For Yacé, yields were 18.56 t/ha with RI, 18.87 t/ha with NPK, and 19.07 t/ha with RI + TRI. The corresponding yields for TMS30572 were 28.76, 28.96, and 29.22 t/ha, respectively. Conclusion: Under the tested conditions, RI alone and RI + TRI produced cassava yields comparable to those obtained with NPK fertiliser and therefore showed potential for supporting more sustainable cassava production.