Effects of silicon on biochemical and physiological aspects in Theobroma cacao under inoculation with Moniliophthora perniciosa

This study aimed to verify the efficiency of silicon leaf application in the physiological and biochemical characteristics in a Theobroma cacao genotype inoculated with Moniliophthora perniciosa fungus, which causes the witches’ broom disease, important cocoa disease in Brazil and worldwide. Seedlings of Catongo genotype were used.  The experimental design used was a randomized block design with four replicates, including two inoculation factors (inoculated and non-inoculated plants), each one with two levels of silicon application (0.0 mg and 1.0 mg mL-1 with AgriSil containing 98% of SiO2). We observed that plants that were inoculated with M. perniciosa and subjected to leaf application with silicon presented enhanced photosynthesis, peroxidases, chitinase, polyphenoloxidases activities and stomatal density. Results have shown that silicon application is beneficial and increases the defenses against Moniliophthora perniciosa in cocoa seedlings.