Characterization and Induction of Biochar Induced Capsicum annumm Defense Against Bacterial Wilt

Abstract

Biochar is considered to have the potential of managing plant diseases by activating plant defense response and influencing the soil-plant-microbe interactions. Therefore, in this study we assessed the soil biochar amendments against bacterial wilt of chilies (Ralstonia solanacearum). Cultivar specific response of chilies to biochar was characterized with reference to physiological and biochemical alterations of the plants. The biochar prepared from leaf waste (LWB) of Syzygium cumini, was applied as a soil amendment at 3 and 6% concentrations along with compost (20%) and the plants were inoculated with or without R. solanacearum. All the cultivars of chilli (Capsicum annumm L.) i.e., F1 Zenia, Desi Chilli and F1 green queen showed a positive impact of biochar amendment on plant growth even under bacterial wilt stress. Although, the reduction in percentage disease index (PDI) and disease incidence (DI) was significant for all cultivars in biochar amended treatments but resistant plant response against wilt was only recorded in cultivar F1 green queen with 6% biochar. The disease response of chili cultivars was not only dependent upon the concentration of biochar in soil but also on the phenolics, catalases and flavonoid contents of the cultivars used. Different chilli cultivars exhibited varied defense response under different biochar concentration. Different chilli cultivars showed variable plant growth in response to the leaf waste biochar amendment. Plant response to disease stress depends not only on the concentration and source of biochar but also on the cultivar. These findings will certainly add to our existing understanding of biochar induced plant resistance as well as cultivar specific chilies defense response against R. solanacearum.