(300-59) Effect of Arbuscular Mycorrhizal Fungi and oyster’s shells powder on cocoa seedlings growth and resistance against Phytophthora megakarya (causal agent of black pod disease) in nursery
Professionnal Researcher Bioetchnology Center of the University of Yaounde 1 Yaounde, Centre, Cameroon
Body of Abstract: Application of organic amendments such as arbuscular mycorrhizal fungi (AMF) as well as chitinous sources have been proposed as a strategy for the management of diseases caused by soil borne pathogens. The aim of this study was to evaluate the combined effect of AMF and oyster shell powder soil amendment to enhance cocoa seedling growth and induce resistance against Phytophthora megakarya under nursery conditions. The results showed that AMF combined with oyster shells powder soil amendment significantly increased plant height, leaf number, leaf area, dry shoot and root weight more than chemical fungicide treatment after five months of growth. This treatment raised soil pH significantly and decrease Phytophthora megakarya load of the soil suspension by 82 %. Leaf inoculation showed the weakest disease severity index (highest level of resistance) recorded in plants treated either with AMF and oyster shell powder combined. Moreover, this resistance was correlated with the increased expression level TcPer-1, TcGlu1, TcChiB and TcMYBPA genes before and after infection. These findings demonstrated that AMF and oyster shell powder combined could be used as biofertilizer and biofungicide to improve the quality of cocoa seedling production and their resistance against Phytophthora megakarya.