Effect of two biocontrols on the accumulation of phenolic compounds and leaf pigments in sorghum [Sorghum bicolor (L.) Moench] leaves in northern Côte d'Ivoire

Abstract

The aim of this study was to find an alternative to chemical control by improving sorghum's natural defense system. The effect of two  biocontrols, Vacciplant and Calliet, on phenolic compound and leaf pigment levels was evaluated. Vacciplant was prepared at  concentrations of 0.675; 0.9; 1.125; 1.35 and 1.575 mg/mL, while Calliet was prepared at concentrations of 4 ; 8 ; 12 ; 16 and 20 mg/mL.  After preparation, the biocontrol solutions were sprayed onto sorghum leaves 60 days old. Incubation times of 24, 48, 72 and 96 hours  were observed after spraying. The sorghum leaves were then harvested and freeze-dried for quantification of total phenols and leaf  pigments. Results showed that Vacciplant at a concentration of 1.125 mg/mL after 72 hours of incubation allowed to have the highest  contents of total phenols (76.63 mg/g MF), while Calliet at concentration of 4.00 mg/mL after 24 hours of incubation allowed to have the  highest contents of total phenols (67.28 mg/g MF). With regard to photosynthetic activity, the results also showed an increase in leaf  pigment content following the application of biocontrols. The use of biocontrols could therefore be an interesting alternative to chemical  control in sorghum.