Silicon (Ca, K & Mg) Induced Resistance in Two Contrasting Rice Genotypes Against Phloem Feeding Pest, Brown Planthopper, Nilaparvata lugens (Stal.) through Modulation of Defense Responses

Abstract

Rice crop is often attacked by several insect pests during its growth stages. Brown planthopper, BPH, is the most serious pest of rice which can cause epidemic losses. Though deployment of durable resistant variety is the safest and economic method of management, the breakdown of resistance is commonly being observed in several cases forcing farmers to use chemical pesticides. Under the negative effects of these chemical pesticides, Silicon provides a promising option as it is beneficial to plants, in alleviating the biotic and abiotic stress by imparting resistance. In the present investigation, attempt was made to manage the pest using different sources of Silicon mainly, Ca₂SiO₄, KSiO₃ and MgSiO₃. All the three forms of Si were applied as seed priming and soil application at 50 and 100 mg/kg of soil. The results showed that, application of Silicon sources enhanced plant growth promoting traits like germination (7–11.50%), seedling length (29.62–45.42%), seedling vigor (35.25–53.28%), seedling weight (33.57–56.19%), number of tillers (40.66–54.79%), number of grains (12.77–20.69%) and grain yield (32.20–49.67%). Significant reduction in pest incidence was recorded evidenced by lowest nymphs settled/plant, lowest nymphal survival, lowest fecundity, increased developmental period, lowest feeding area, maximum probing marks, lowest Functional Plant Loss Index and lowest percent wilted plants. Similarly, enhanced activities of Peroxidase, Polyphenol oxidase, Catalase and Super oxide dismutase were recorded in Silicon treated plants. Proteomic analysis using SDS-PAGE clearly produced thick bands at 43, 66 and 97.40 kDa range in all the Silicon treated plants. Among the Silicon sources, it was Potassium silicate performed better compared to Ca and Mg silicates. The results of the present investigation provided additional insights into the Induced Systemic Resistance activities of the Silicon sources in two contrasting genotypes and provided clues for the researchers to formulate suitable eco-friendly management measures.